diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 0000000..9fa9757
--- /dev/null
+++ b/.github/workflows/test.yml
@@ -0,0 +1,36 @@
+name: tests
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  site-checks:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      # Stdlib only (minitest + yaml) — no `bundle install` needed,
+      # so this stays fast.
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: "3.4"
+      - run: ruby -Itests tests/test_site.rb
+
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: "3.4"
+          bundler-cache: true
+      # --strict-front-matter fails on YAML errors; --future also
+      # compiles scheduled posts so broken Liquid/post_url in them
+      # surfaces now instead of on their go-live date.
+      - run: bundle exec jekyll build --strict-front-matter --future
+      # Internal links, images, and alt text only — external URLs are
+      # left out to keep PR checks deterministic (no network flakiness).
+      # Installed outside the Gemfile on purpose: production (GitHub
+      # Pages) must keep the exact github-pages gem set.
+      - run: gem install html-proofer --no-document
+      - run: htmlproofer ./_site --disable-external --allow-hash-href
diff --git a/.gitignore b/.gitignore
index f40fbd8..1960d5a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,5 @@ _site
 .jekyll-cache
 .jekyll-metadata
 vendor
+.DS_Store
+__pycache__/
diff --git a/404.html b/404.html
index 086a5c9..a00cd00 100644
--- a/404.html
+++ b/404.html
@@ -22,4 +22,6 @@ <h1>404</h1>
 
   <p><strong>Page not found :(</strong></p>
   <p>The requested page could not be found.</p>
+  <p><a href="{{ "/" | relative_url }}">Back to home</a></p>
+  <p>Or browse the <a href="{{ "/archive/" | relative_url }}">archive</a> and <a href="{{ "/tags/" | relative_url }}">tags</a>.</p>
 </div>
diff --git a/Gemfile.lock b/Gemfile.lock
index 517ecf2..d92ba50 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -225,7 +225,7 @@ GEM
       gemoji (>= 3, < 5)
       html-pipeline (~> 2.2)
       jekyll (>= 3.0, < 5.0)
-    json (2.21.2)
+    json (3.0.0)
     kramdown (2.4.0)
       rexml
     kramdown-parser-gfm (1.1.0)
@@ -386,7 +386,7 @@ CHECKSUMS
   jekyll-titles-from-headings (0.5.3) sha256=77366754e361ea7b5d87881f5b1380835f5ce910c240a4d9ac2d7afe86d28481
   jekyll-watch (2.2.1) sha256=bc44ed43f5e0a552836245a54dbff3ea7421ecc2856707e8a1ee203a8387a7e1
   jemoji (0.13.0) sha256=5d4c3e8e2cbbb2b73997c31294f6f70c94e4d4fade039373e86835bcf5529e7c
-  json (2.21.2) sha256=1f1d3b7cf2b3ba1a69beca0bb6db13d5438b80bff3cd54cdaaa620b9b07c1c6a
+  json (3.0.0) sha256=1ff82a28c05c5cc7b646f3e3a3ac710e4ae2aa933690cba12f1f650b0ecdeb99
   kramdown (2.4.0) sha256=b62e5bcbd6ea20c7a6730ebbb2a107237856e14f29cebf5b10c876cc1a2481c5
   kramdown-parser-gfm (1.1.0) sha256=fb39745516427d2988543bf01fc4cf0ab1149476382393e0e9c48592f6581729
   liquid (4.0.4) sha256=4fcfebb1a045e47918388dbb7a0925e7c3893e58d2bd6c3b3c73ec17a2d8fdb3
diff --git a/LICENSE.md b/LICENSE.md
new file mode 100644
index 0000000..1020e2b
--- /dev/null
+++ b/LICENSE.md
@@ -0,0 +1,694 @@
+# License
+
+## Site code and code examples: GNU GPLv3 or later
+
+The site machinery in this repository — layouts, includes, stylesheets,
+scripts, and configuration — and fenced code blocks inside blog posts are
+© David Budzyński and licensed under the GNU General Public License,
+either version 3 of the License, or (at your option) any later version.
+The full text follows below.
+
+## Prose and images: CC BY-NC-ND 4.0
+
+Blog post prose and images (`_posts/`, `_drafts/`, `assets/images/`) are
+© David Budzyński and shared under
+[CC BY-NC-ND 4.0](https://creativecommons.org/licenses/by-nc-nd/4.0/):
+you may share verbatim copies for non-commercial purposes with attribution,
+but do not adapt them or use them commercially without permission — ask via
+[GitHub](https://github.com/davidbudzynski) first.
+
+---
+
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
+
+  The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works.  By contrast,
+the GNU General Public License is intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users.  We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors.  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+  To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights.  Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received.  You must make sure that they, too, receive
+or can get the source code.  And you must show them these terms so they
+know their rights.
+
+  Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
+
+  For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software.  For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+  Some devices are designed to deny users access to install or run
+modified versions of the software inside them, although the manufacturer
+can do so.  This is fundamentally incompatible with the aim of
+protecting users' freedom to change the software.  The systematic
+pattern of such abuse occurs in the area of products for individuals to
+use, which is precisely where it is most unacceptable.  Therefore, we
+have designed this version of the GPL to prohibit the practice for those
+products.  If such problems arise substantially in other domains, we
+stand ready to extend this provision to those domains in future versions
+of the GPL, as needed to protect the freedom of users.
+
+  Finally, every program is threatened constantly by software patents.
+States should not allow patents to restrict development and use of
+software on general-purpose computers, but in those that do, we wish to
+avoid the special danger that patents applied to a free program could
+make it effectively proprietary.  To prevent this, the GPL assures that
+patents cannot be used to render the program non-free.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                       TERMS AND CONDITIONS
+
+  0. Definitions.
+
+  "This License" refers to version 3 of the GNU General Public License.
+
+  "Copyright" also means copyright-like laws that apply to other kinds of
+works, such as semiconductor masks.
+
+  "The Program" refers to any copyrightable work licensed under this
+License.  Each licensee is addressed as "you".  "Licensees" and
+"recipients" may be individuals or organizations.
+
+  To "modify" a work means to copy from or adapt all or part of the work
+in a fashion requiring copyright permission, other than the making of an
+exact copy.  The resulting work is called a "modified version" of the
+earlier work or a work "based on" the earlier work.
+
+  A "covered work" means either the unmodified Program or a work based
+on the Program.
+
+  To "propagate" a work means to do anything with it that, without
+permission, would make you directly or secondarily liable for
+infringement under applicable copyright law, except executing it on a
+computer or modifying a private copy.  Propagation includes copying,
+distribution (with or without modification), making available to the
+public, and in some countries other activities as well.
+
+  To "convey" a work means any kind of propagation that enables other
+parties to make or receive copies.  Mere interaction with a user through
+a computer network, with no transfer of a copy, is not conveying.
+
+  An interactive user interface displays "Appropriate Legal Notices"
+to the extent that it includes a convenient and prominently visible
+feature that (1) displays an appropriate copyright notice, and (2)
+tells the user that there is no warranty for the work (except to the
+extent that warranties are provided), that licensees may convey the
+work under this License, and how to view a copy of this License.  If
+the interface presents a list of user commands or options, such as a
+menu, a prominent item in the list meets this criterion.
+
+  1. Source Code.
+
+  The "source code" for a work means the preferred form of the work
+for making modifications to it.  "Object code" means any non-source
+form of a work.
+
+  A "Standard Interface" means an interface that either is an official
+standard defined by a recognized standards body, or, in the case of
+interfaces specified for a particular programming language, one that
+is widely used among developers working in that language.
+
+  The "System Libraries" of an executable work include anything, other
+than the work as a whole, that (a) is included in the normal form of
+packaging a Major Component, but which is not part of that Major
+Component, and (b) serves only to enable use of the work with that
+Major Component, or to implement a Standard Interface for which an
+implementation is available to the public in source code form.  A
+"Major Component", in this context, means a major essential component
+(kernel, window system, and so on) of the specific operating system
+(if any) on which the executable work runs, or a compiler used to
+produce the work, or an object code interpreter used to run it.
+
+  The "Corresponding Source" for a work in object code form means all
+the source code needed to generate, install, and (for an executable
+work) run the object code and to modify the work, including scripts to
+control those activities.  However, it does not include the work's
+System Libraries, or general-purpose tools or generally available free
+programs which are used unmodified in performing those activities but
+which are not part of the work.  For example, Corresponding Source
+includes interface definition files associated with source files for
+the work, and the source code for shared libraries and dynamically
+linked subprograms that the work is specifically designed to require,
+such as by intimate data communication or control flow between those
+subprograms and other parts of the work.
+
+  The Corresponding Source need not include anything that users
+can regenerate automatically from other parts of the Corresponding
+Source.
+
+  The Corresponding Source for a work in source code form is that
+same work.
+
+  2. Basic Permissions.
+
+  All rights granted under this License are granted for the term of
+copyright on the Program, and are irrevocable provided the stated
+conditions are met.  This License explicitly affirms your unlimited
+permission to run the unmodified Program.  The output from running a
+covered work is covered by this License only if the output, given its
+content, constitutes a covered work.  This License acknowledges your
+rights of fair use or other equivalent, as provided by copyright law.
+
+  You may make, run and propagate covered works that you do not
+convey, without conditions so long as your license otherwise remains
+in force.  You may convey covered works to others for the sole purpose
+of having them make modifications exclusively for you, or provide you
+with facilities for running those works, provided that you comply with
+the terms of this License in conveying all material for which you do
+not control copyright.  Those thus making or running the covered works
+for you must do so exclusively on your behalf, under your direction
+and control, on terms that prohibit them from making any copies of
+your copyrighted material outside their relationship with you.
+
+  Conveying under any other circumstances is permitted solely under
+the conditions stated below.  Sublicensing is not allowed; section 10
+makes it unnecessary.
+
+  3. Protecting Users' Legal Rights From Anti-Circumvention Law.
+
+  No covered work shall be deemed part of an effective technological
+measure under any applicable law fulfilling obligations under article
+11 of the WIPO copyright treaty adopted on 20 December 1996, or
+similar laws prohibiting or restricting circumvention of such
+measures.
+
+  When you convey a covered work, you waive any legal power to forbid
+circumvention of technological measures to the extent such circumvention
+is effected by exercising rights under this License with respect to
+the covered work, and you disclaim any intention to limit operation or
+modification of the work as a means of enforcing, against the work's
+users, your or third parties' legal rights to forbid circumvention of
+technological measures.
+
+  4. Conveying Verbatim Copies.
+
+  You may convey verbatim copies of the Program's source code as you
+receive it, in any medium, provided that you conspicuously and
+appropriately publish on each copy an appropriate copyright notice;
+keep intact all notices stating that this License and any
+non-permissive terms added in accord with section 7 apply to the code;
+keep intact all notices of the absence of any warranty; and give all
+recipients a copy of this License along with the Program.
+
+  You may charge any price or no price for each copy that you convey,
+and you may offer support or warranty protection for a fee.
+
+  5. Conveying Modified Source Versions.
+
+  You may convey a work based on the Program, or the modifications to
+produce it from the Program, in the form of source code under the
+terms of section 4, provided that you also meet all of these conditions:
+
+    a) The work must carry prominent notices stating that you modified
+    it, and giving a relevant date.
+
+    b) The work must carry prominent notices stating that it is
+    released under this License and any conditions added under section
+    7.  This requirement modifies the requirement in section 4 to
+    "keep intact all notices".
+
+    c) You must license the entire work, as a whole, under this
+    License to anyone who comes into possession of a copy.  This
+    License will therefore apply, along with any applicable section 7
+    additional terms, to the whole of the work, and all its parts,
+    regardless of how they are packaged.  This License gives no
+    permission to license the work in any other way, but it does not
+    invalidate such permission if you have separately received it.
+
+    d) If the work has interactive user interfaces, each must display
+    Appropriate Legal Notices; however, if the Program has interactive
+    interfaces that do not display Appropriate Legal Notices, your
+    work need not make them do so.
+
+  A compilation of a covered work with other separate and independent
+works, which are not by their nature extensions of the covered work,
+and which are not combined with it such as to form a larger program,
+in or on a volume of a storage or distribution medium, is called an
+"aggregate" if the compilation and its resulting copyright are not
+used to limit the access or legal rights of the compilation's users
+beyond what the individual works permit.  Inclusion of a covered work
+in an aggregate does not cause this License to apply to the other
+parts of the aggregate.
+
+  6. Conveying Non-Source Forms.
+
+  You may convey a covered work in object code form under the terms
+of sections 4 and 5, provided that you also convey the
+machine-readable Corresponding Source under the terms of this License,
+in one of these ways:
+
+    a) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by the
+    Corresponding Source fixed on a durable physical medium
+    customarily used for software interchange.
+
+    b) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by a
+    written offer, valid for at least three years and valid for as
+    long as you offer spare parts or customer support for that product
+    model, to give anyone who possesses the object code either (1) a
+    copy of the Corresponding Source for all the software in the
+    product that is covered by this License, on a durable physical
+    medium customarily used for software interchange, for a price no
+    more than your reasonable cost of physically performing this
+    conveying of source, or (2) access to copy the
+    Corresponding Source from a network server at no charge.
+
+    c) Convey individual copies of the object code with a copy of the
+    written offer to provide the Corresponding Source.  This
+    alternative is allowed only occasionally and noncommercially, and
+    only if you received the object code with such an offer, in accord
+    with subsection 6b.
+
+    d) Convey the object code by offering access from a designated
+    place (gratis or for a charge), and offer equivalent access to the
+    Corresponding Source in the same way through the same place at no
+    further charge.  You need not require recipients to copy the
+    Corresponding Source along with the object code.  If the place to
+    copy the object code is a network server, the Corresponding Source
+    may be on a different server (operated by you or a third party)
+    that supports equivalent copying facilities, provided you maintain
+    clear directions next to the object code saying where to find the
+    Corresponding Source.  Regardless of what server hosts the
+    Corresponding Source, you remain obligated to ensure that it is
+    available for as long as needed to satisfy these requirements.
+
+    e) Convey the object code using peer-to-peer transmission, provided
+    you inform other peers where the object code and Corresponding
+    Source of the work are being offered to the general public at no
+    charge under subsection 6d.
+
+  A separable portion of the object code, whose source code is excluded
+from the Corresponding Source as a System Library, need not be
+included in conveying the object code work.
+
+  A "User Product" is either (1) a "consumer product", which means any
+tangible personal property which is normally used for personal, family,
+or household purposes, or (2) anything designed or sold for incorporation
+into a dwelling.  In determining whether a product is a consumer product,
+doubtful cases shall be resolved in favor of coverage.  For a particular
+product received by a particular user, "normally used" refers to a
+typical or common use of that class of product, regardless of the status
+of the particular user or of the way in which the particular user
+actually uses, or expects or is expected to use, the product.  A product
+is a consumer product regardless of whether the product has substantial
+commercial, industrial or non-consumer uses, unless such uses represent
+the only significant mode of use of the product.
+
+  "Installation Information" for a User Product means any methods,
+procedures, authorization keys, or other information required to install
+and execute modified versions of a covered work in that User Product from
+a modified version of its Corresponding Source.  The information must
+suffice to ensure that the continued functioning of the modified object
+code is in no case prevented or interfered with solely because
+modification has been made.
+
+  If you convey an object code work under this section in, or with, or
+specifically for use in, a User Product, and the conveying occurs as
+part of a transaction in which the right of possession and use of the
+User Product is transferred to the recipient in perpetuity or for a
+fixed term (regardless of how the transaction is characterized), the
+Corresponding Source conveyed under this section must be accompanied
+by the Installation Information.  But this requirement does not apply
+if neither you nor any third party retains the ability to install
+modified object code on the User Product (for example, the work has
+been installed in ROM).
+
+  The requirement to provide Installation Information does not include a
+requirement to continue to provide support service, warranty, or updates
+for a work that has been modified or installed by the recipient, or for
+the User Product in which it has been modified or installed.  Access to a
+network may be denied when the modification itself materially and
+adversely affects the operation of the network or violates the rules and
+protocols for communication across the network.
+
+  Corresponding Source conveyed, and Installation Information provided,
+in accord with this section must be in a format that is publicly
+documented (and with an implementation available to the public in
+source code form), and must require no special password or key for
+unpacking, reading or copying.
+
+  7. Additional Terms.
+
+  "Additional permissions" are terms that supplement the terms of this
+License by making exceptions from one or more of its conditions.
+Additional permissions that are applicable to the entire Program shall
+be treated as though they were included in this License, to the extent
+that they are valid under applicable law.  If additional permissions
+apply only to part of the Program, that part may be used separately
+under those permissions, but the entire Program remains governed by
+this License without regard to the additional permissions.
+
+  When you convey a copy of a covered work, you may at your option
+remove any additional permissions from that copy, or from any part of
+it.  (Additional permissions may be written to require their own
+removal in certain cases when you modify the work.)  You may place
+additional permissions on material, added by you to a covered work,
+for which you have or can give appropriate copyright permission.
+
+  Notwithstanding any other provision of this License, for material you
+add to a covered work, you may (if authorized by the copyright holders of
+that material) supplement the terms of this License with terms:
+
+    a) Disclaiming warranty or limiting liability differently from the
+    terms of sections 15 and 16 of this License; or
+
+    b) Requiring preservation of specified reasonable legal notices or
+    author attributions in that material or in the Appropriate Legal
+    Notices displayed by works containing it; or
+
+    c) Prohibiting misrepresentation of the origin of that material, or
+    requiring that modified versions of such material be marked in
+    reasonable ways as different from the original version; or
+
+    d) Limiting the use for publicity purposes of names of licensors or
+    authors of the material; or
+
+    e) Declining to grant rights under trademark law for use of some
+    trade names, trademarks, or service marks; or
+
+    f) Requiring indemnification of licensors and authors of that
+    material by anyone who conveys the material (or modified versions of
+    it) with contractual assumptions of liability to the recipient, for
+    any liability that these contractual assumptions directly impose on
+    those licensors and authors.
+
+  All other non-permissive additional terms are considered "further
+restrictions" within the meaning of section 10.  If the Program as you
+received it, or any part of it, contains a notice stating that it is
+governed by this License along with a term that is a further
+restriction, you may remove that term.  If a license document contains
+a further restriction but permits relicensing or conveying under this
+License, you may add to a covered work material governed by the terms
+of that license document, provided that the further restriction does
+not survive such relicensing or conveying.
+
+  If you add terms to a covered work in accord with this section, you
+must place, in the relevant source files, a statement of the
+additional terms that apply to those files, or a notice indicating
+where to find the applicable terms.
+
+  Additional terms, permissive or non-permissive, may be stated in the
+form of a separately written license, or stated as exceptions;
+the above requirements apply either way.
+
+  8. Termination.
+
+  You may not propagate or modify a covered work except as expressly
+provided under this License.  Any attempt otherwise to propagate or
+modify it is void, and will automatically terminate your rights under
+this License (including any patent licenses granted under the third
+paragraph of section 11).
+
+  However, if you cease all violation of this License, then your
+license from a particular copyright holder is reinstated (a)
+provisionally, unless and until the copyright holder explicitly and
+finally terminates your license, and (b) permanently, if the copyright
+holder fails to notify you of the violation by some reasonable means
+prior to 60 days after the cessation.
+
+  Moreover, your license from a particular copyright holder is
+reinstated permanently if the copyright holder notifies you of the
+violation by some reasonable means, this is the first time you have
+received notice of violation of this License (for any work) from that
+copyright holder, and you cure the violation prior to 30 days after
+your receipt of the notice.
+
+  Termination of your rights under this section does not terminate the
+licenses of parties who have received copies or rights from you under
+this License.  If your rights have been terminated and not permanently
+reinstated, you do not qualify to receive new licenses for the same
+material under section 10.
+
+  9. Acceptance Not Required for Having Copies.
+
+  You are not required to accept this License in order to receive or
+run a copy of the Program.  Ancillary propagation of a covered work
+occurring solely as a consequence of using peer-to-peer transmission
+to receive a copy likewise does not require acceptance.  However,
+nothing other than this License grants you permission to propagate or
+modify any covered work.  These actions infringe copyright if you do
+not accept this License.  Therefore, by modifying or propagating a
+covered work, you indicate your acceptance of this License to do so.
+
+  10. Automatic Licensing of Downstream Recipients.
+
+  Each time you convey a covered work, the recipient automatically
+receives a license from the original licensors, to run, modify and
+propagate that work, subject to this License.  You are not responsible
+for enforcing compliance by third parties with this License.
+
+  An "entity transaction" is a transaction transferring control of an
+organization, or substantially all assets of one, or merging organizations.
+If propagation of a covered work results from an entity transaction, each
+party to that transaction who receives a copy of the work also receives
+whatever licenses to the work the party's predecessor in interest had or
+could give under the previous paragraph, plus a right to possession of the
+Corresponding Source of the work from the predecessor in interest, if
+the predecessor has it or can get it with reasonable efforts.
+
+  You may not impose any further restrictions on the exercise of the
+rights granted or affirmed under this License.  For example, you may
+not impose a license fee, royalty, or other charge for exercise of
+rights granted under this License, and you may not initiate litigation
+(including a cross-claim or counterclaim in a lawsuit) alleging that
+any patent claim is infringed by making, using, selling, offering for
+sale, or importing the Program or any portion of it.
+
+  11. Patents.
+
+  A "contributor" is a copyright holder who authorizes use under this
+License of the Program or a work on which the Program is based.  The
+work thus licensed is called the contributor's "contributor version".
+
+  A contributor's "essential patent claims" are all patent claims
+owned or controlled by the contributor, whether already acquired or
+hereafter acquired, that would be infringed by some manner, permitted
+by this License, of making, using, or selling its contributor version,
+but do not include claims that would be infringed only as a
+consequence of further modification of the contributor version.  For
+purposes of this definition, "control" includes the right to grant
+patent sublicenses in a manner consistent with the requirements of
+this License.
+
+  Each contributor grants you a non-exclusive, worldwide, royalty-free
+patent license under the contributor's essential patent claims, to
+make, use, sell, offer for sale, import and otherwise run, modify and
+propagate the contents of its contributor version.
+
+  In the following three paragraphs, a "patent license" is any express
+agreement or commitment, however denominated, not to enforce a patent
+(such as an express permission to practice a patent or covenant not to
+sue for patent infringement).  To "grant" such a patent license to a
+party means to make such an agreement or commitment not to enforce a
+patent against the party.
+
+  If you convey a covered work, knowingly relying on a patent license,
+and the Corresponding Source of the work is not available for anyone
+to copy, free of charge and under the terms of this License, through a
+publicly available network server or other readily accessible means,
+then you must either (1) cause the Corresponding Source to be so
+available, or (2) arrange to deprive yourself of the benefit of the
+patent license for this particular work, or (3) arrange, in a manner
+consistent with the requirements of this License, to extend the patent
+license to downstream recipients.  "Knowingly relying" means you have
+actual knowledge that, but for the patent license, your conveying the
+covered work in a country, or your recipient's use of the covered work
+in a country, would infringe one or more identifiable patents in that
+country that you have reason to believe are valid.
+
+  If, pursuant to or in connection with a single transaction or
+arrangement, you convey, or propagate by procuring conveyance of, a
+covered work, and grant a patent license to some of the parties
+receiving the covered work authorizing them to use, propagate, modify
+or convey a specific copy of the covered work, then the patent license
+you grant is automatically extended to all recipients of the covered
+work and works based on it.
+
+  A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License.  You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all.  For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+  13. Use with the GNU Affero General Public License.
+
+  Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.
diff --git a/README.md b/README.md
index 5a20180..a2488f6 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,13 @@ It's a simple Jekyll-powered site, that I deploy on GitHub pages.
 
 Feel free to send PRs addressing typos, bad grammar, visual glitches, etc.
 
+## License
+
+Site code and fenced code examples in posts are [GPLv3 or later](LICENSE.md).
+Post prose and images are © David Budzyński, shared under
+[CC BY-NC-ND 4.0](https://creativecommons.org/licenses/by-nc-nd/4.0/).
+See [LICENSE.md](LICENSE.md) for details.
+
 To run the site locally, you need to have Ruby installed (macOS and Linux are
 both supported). Then run the following commands:
 
diff --git a/_config.yml b/_config.yml
index 107c2c2..ad5a79d 100644
--- a/_config.yml
+++ b/_config.yml
@@ -20,6 +20,8 @@
 
 title: David Budzyński
 author: David Budzyński
+lang: en-GB
+timezone: Europe/London
 # email: your-email@example.com
 description: >- # this means to ignore newlines until "baseurl:"
   This is my blog where I share my thoughts on statistics, computer science, software, and technology.
@@ -28,12 +30,42 @@ url: "https://davidbudzynski.github.io" # the base hostname & protocol for your
 github_username: davidbudzynski
 rss: RSS
 
+# Explicit permalink without :categories so URLs stay stable even if a
+# category ever slips back into front matter.
+permalink: /:year/:month/:day/:title.html
+# Scheduled posts (future-dated) stay hidden until their date — intentional.
+future: false
+excerpt_separator: <!--more-->
+show_excerpts: true
+
+header_pages:
+  - about.md
+  - projects.md
+  - archive.md
+  - tags.html
+  - search.md
+
+minima:
+  # NOTE: github-pages pins minima 2.5.1, which ignores `skin`.
+  # Kept as forward-compat for minima 3.x (auto = light/dark by OS setting).
+  skin: auto
+  # Social icons on minima 2.5.x come from the legacy `github_username` /
+  # `rss` keys above via _includes/social.html, not from social_links.
+
+defaults:
+  - scope:
+      path: ""
+      type: posts
+    values:
+      layout: post
+
 # Build settings
 theme: minima
 plugins:
   - jekyll-feed
   - jekyll-sitemap
   - jekyll-seo-tag
+  - jekyll-redirect-from
 # Exclude from processing.
 # The following items will not be processed, by default.
 # Any item listed under the `exclude:` key here will be automatically added to
@@ -49,6 +81,7 @@ exclude:
   - Gemfile
   - Gemfile.lock
   - node_modules/
+  - tests/
   - vendor/bundle/
   - vendor/cache/
   - vendor/gems/
diff --git a/_drafts/agent-skills-i-like-using.md b/_drafts/agent-skills-i-like-using.md
index 6488be4..35d7f84 100644
--- a/_drafts/agent-skills-i-like-using.md
+++ b/_drafts/agent-skills-i-like-using.md
@@ -5,4 +5,6 @@ tags   : [AI, Software, Tooling]
 ---
 
 A tour of the skills, tools, and capabilities I enable for my coding agent, and
-which ones I keep disabled.
\ No newline at end of file
+which ones I keep disabled.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/automating-boring-tasks.md b/_drafts/automating-boring-tasks.md
index e67c5ce..30bc166 100644
--- a/_drafts/automating-boring-tasks.md
+++ b/_drafts/automating-boring-tasks.md
@@ -5,4 +5,6 @@ tags   : [Linux, Shell, Tooling]
 ---
 
 How I stop repeating myself: scripts and Makefiles for the chores that used to
-waste my time.
\ No newline at end of file
+waste my time.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/browser-extensions-that-respect-privacy.md b/_drafts/browser-extensions-that-respect-privacy.md
index a27a58d..2bf419e 100644
--- a/_drafts/browser-extensions-that-respect-privacy.md
+++ b/_drafts/browser-extensions-that-respect-privacy.md
@@ -4,4 +4,6 @@ title  : "Browser extensions that respect your privacy"
 tags   : [Web, Privacy]
 ---
 
-The extensions I trust and use, and the ones I avoid.
\ No newline at end of file
+The extensions I trust and use, and the ones I avoid.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/firefox-customization-part-2.md b/_drafts/firefox-customization-part-2.md
index 03dac61..6779e29 100644
--- a/_drafts/firefox-customization-part-2.md
+++ b/_drafts/firefox-customization-part-2.md
@@ -5,4 +5,6 @@ tags   : [Web, Software, Privacy]
 ---
 
 A deeper dive into Firefox customization with userChrome.css examples, following
-up on the earlier Firefox post.
\ No newline at end of file
+up on the earlier Firefox post.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/five-years-in-linux.md b/_drafts/five-years-in-linux.md
index c83d39a..b6b5bc5 100644
--- a/_drafts/five-years-in-linux.md
+++ b/_drafts/five-years-in-linux.md
@@ -5,4 +5,6 @@ tags   : [Linux]
 ---
 
 A retrospective on the original "Two Years in Linux" post, updated with what
-changed over the following years.
\ No newline at end of file
+changed over the following years.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/how-i-use-an-agent-day-to-day.md b/_drafts/how-i-use-an-agent-day-to-day.md
index 1f31839..a44e3cc 100644
--- a/_drafts/how-i-use-an-agent-day-to-day.md
+++ b/_drafts/how-i-use-an-agent-day-to-day.md
@@ -5,4 +5,6 @@ tags   : [AI, Software, Tooling]
 ---
 
 A realistic walkthrough of a session with my agent: from prompt to a reviewed,
-committed change, including where it shines and where it trips up.
\ No newline at end of file
+committed change, including where it shines and where it trips up.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/lessons-from-10-years-of-r.md b/_drafts/lessons-from-10-years-of-r.md
index cb92bd8..4c8ba9a 100644
--- a/_drafts/lessons-from-10-years-of-r.md
+++ b/_drafts/lessons-from-10-years-of-r.md
@@ -5,4 +5,6 @@ tags   : [R, Data Science]
 ---
 
 What a decade of R taught me about statistics, coding, and tooling. Advice I
-would give my younger self.
\ No newline at end of file
+would give my younger self.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/my-dotfiles-setup.md b/_drafts/my-dotfiles-setup.md
index b6c6c41..fb8fbae 100644
--- a/_drafts/my-dotfiles-setup.md
+++ b/_drafts/my-dotfiles-setup.md
@@ -4,4 +4,6 @@ title  : "My dotfiles setup and how I manage them"
 tags   : [Linux, Tooling]
 ---
 
-How I structure, version, and sync my dotfiles across machines.
\ No newline at end of file
+How I structure, version, and sync my dotfiles across machines.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/my-python-setup-in-2026.md b/_drafts/my-python-setup-in-2026.md
index f539f2c..572e8e3 100644
--- a/_drafts/my-python-setup-in-2026.md
+++ b/_drafts/my-python-setup-in-2026.md
@@ -5,4 +5,6 @@ tags   : [Python, Tooling]
 ---
 
 uv, ruff, pyright. Why I stopped caring about pip and venv, and how a modern
-Python setup looks in practice.
\ No newline at end of file
+Python setup looks in practice.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/program-spotlight-cli-tools.md b/_drafts/program-spotlight-cli-tools.md
index eebbc01..56d67ca 100644
--- a/_drafts/program-spotlight-cli-tools.md
+++ b/_drafts/program-spotlight-cli-tools.md
@@ -5,4 +5,6 @@ tags   : [Software, CLI]
 ---
 
 Part of the Program Spotlight series (following rclone and file managers). Covers
-fzf, ripgrep, tmux, zoxide, and bat.
\ No newline at end of file
+fzf, ripgrep, tmux, zoxide, and bat.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/program-spotlight-paperless-ngx.md b/_drafts/program-spotlight-paperless-ngx.md
index 723b12e..404914b 100644
--- a/_drafts/program-spotlight-paperless-ngx.md
+++ b/_drafts/program-spotlight-paperless-ngx.md
@@ -5,4 +5,6 @@ tags   : [Software, Self-hosting]
 ---
 
 Document management done right: OCR, tagging, and search. Part of the Program
-Spotlight series.
\ No newline at end of file
+Spotlight series.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/python-packages-beyond-pandas-numpy.md b/_drafts/python-packages-beyond-pandas-numpy.md
index bdcb4c5..fe9f723 100644
--- a/_drafts/python-packages-beyond-pandas-numpy.md
+++ b/_drafts/python-packages-beyond-pandas-numpy.md
@@ -5,4 +5,6 @@ tags   : [Python, Data Science]
 ---
 
 A personal list of the Python packages I reach for constantly that most people
-never hear about.
\ No newline at end of file
+never hear about.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/self-hosting-paperless-ngx.md b/_drafts/self-hosting-paperless-ngx.md
index 4edcb51..a812722 100644
--- a/_drafts/self-hosting-paperless-ngx.md
+++ b/_drafts/self-hosting-paperless-ngx.md
@@ -5,4 +5,6 @@ tags   : [Self-hosting, Privacy]
 ---
 
 Paperless-ngx as a gateway into self-hosting: the setup, the payoff, and what
-came after.
\ No newline at end of file
+came after.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/using-rss-and-why-its-good.md b/_drafts/using-rss-and-why-its-good.md
index 386762b..429782b 100644
--- a/_drafts/using-rss-and-why-its-good.md
+++ b/_drafts/using-rss-and-why-its-good.md
@@ -5,4 +5,6 @@ tags   : [RSS, Web, Privacy]
 ---
 
 Why RSS is still the best way to follow what matters, and how to set up a
-reader that actually fits your life.
\ No newline at end of file
+reader that actually fits your life.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/what-is-agentic-coding.md b/_drafts/what-is-agentic-coding.md
index 1b7016a..66dc11b 100644
--- a/_drafts/what-is-agentic-coding.md
+++ b/_drafts/what-is-agentic-coding.md
@@ -5,4 +5,6 @@ tags   : [AI, Software, Tooling]
 ---
 
 A grounded introduction to agentic coding: what the tools actually do, their
-limits, and the hype vs. reality.
\ No newline at end of file
+limits, and the hype vs. reality.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/why-i-keep-this-blog.md b/_drafts/why-i-keep-this-blog.md
index b54ddaa..6005808 100644
--- a/_drafts/why-i-keep-this-blog.md
+++ b/_drafts/why-i-keep-this-blog.md
@@ -5,4 +5,6 @@ tags   : [Meta, Writing]
 ---
 
 Reflections on running a small Jekyll blog on GitHub Pages: the writing
-pipeline, what I get out of it, and why I keep going.
\ No newline at end of file
+pipeline, what I get out of it, and why I keep going.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/why-i-moved-my-r-workflow-to-python.md b/_drafts/why-i-moved-my-r-workflow-to-python.md
index 3ea3021..7a3061c 100644
--- a/_drafts/why-i-moved-my-r-workflow-to-python.md
+++ b/_drafts/why-i-moved-my-r-workflow-to-python.md
@@ -5,4 +5,6 @@ tags   : [R, Python, Data Science]
 ---
 
 Follow-up to "R is a Terrible Programming Language". What drove the migration,
-what I kept in R, and how the transition went in practice.
\ No newline at end of file
+what I kept in R, and how the transition went in practice.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/why-i-still-read-diffs.md b/_drafts/why-i-still-read-diffs.md
index c063154..025852b 100644
--- a/_drafts/why-i-still-read-diffs.md
+++ b/_drafts/why-i-still-read-diffs.md
@@ -5,4 +5,6 @@ tags   : [AI, Software, Tooling]
 ---
 
 Agent-generated code still needs review. What I auto-accept, what I always
-rewrite, and how I keep my git hygiene intact.
\ No newline at end of file
+rewrite, and how I keep my git hygiene intact.
+
+<!--more-->
\ No newline at end of file
diff --git a/_drafts/why-i-use-a-tiling-window-manager.md b/_drafts/why-i-use-a-tiling-window-manager.md
index 6315d3b..a5344ba 100644
--- a/_drafts/why-i-use-a-tiling-window-manager.md
+++ b/_drafts/why-i-use-a-tiling-window-manager.md
@@ -5,4 +5,6 @@ tags   : [Linux, WM]
 ---
 
 The workflow and productivity argument for tiling window managers, based on my
-own daily setup.
\ No newline at end of file
+own daily setup.
+
+<!--more-->
\ No newline at end of file
diff --git a/_includes/footer.html b/_includes/footer.html
index 041b48a..31fd5f1 100644
--- a/_includes/footer.html
+++ b/_includes/footer.html
@@ -30,6 +30,13 @@
       </div>
     </div>
 
+    <div class="footer-license">
+      <p>© 2021–2026 David Budzyński. Prose and images:
+      <a href="https://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND 4.0</a>.
+      Site code and code examples:
+      <a href="{{ "/LICENSE.md" | relative_url }}">GPLv3 or later</a>.</p>
+    </div>
+
   </div>
 
 </footer>
diff --git a/_includes/head.html b/_includes/head.html
index 23eeba0..15e6116 100644
--- a/_includes/head.html
+++ b/_includes/head.html
@@ -3,7 +3,10 @@
   <meta http-equiv="X-UA-Compatible" content="IE=edge">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   {%- seo -%}
+  <meta name="theme-color" content="#fdfdfd" media="(prefers-color-scheme: light)">
+  <meta name="theme-color" content="#1a1a1a" media="(prefers-color-scheme: dark)">
   <link rel="stylesheet" href="{{ "/assets/main.css" | relative_url }}">
   <link rel="icon" href="{{ "/favicon.ico" | relative_url }}">
+  <link rel="apple-touch-icon" href="{{ "/favicon.ico" | relative_url }}">
   {%- feed_meta -%}
 </head>
diff --git a/_includes/utterances.html b/_includes/utterances.html
index 757eeec..0643721 100644
--- a/_includes/utterances.html
+++ b/_includes/utterances.html
@@ -1,41 +1,20 @@
-<!-- 
-    check this link for how to use utterances: each github repo has to be set up
-    initially when using utterances, so keep that in mind for any new projects
-
-    The label argument takes only lables which are already created in the github
-    repo. comment is not a default label, so it has to be created in the github
-    repo first
-
-    https://utteranc.es/
-
-
-    some of the code below is also inspired by the following link:
-    https://gist.github.com/mwt/7b747b45d5e28e7a943490d7a3b8a4ff
-
-    It didn't initially work for me, but I think it was because I didn't have
-    the the _layouts/post.html file set up correctly. I had to add it. If you
-    don't have this file you need to create it with the existing html for your
-    current theme. I use the default one (minima) so I just copied the html from
-    here:
-    https://github.com/jekyll/minima/blob/38a84a949f9753c4542e25f422935f59b4913053/_layouts/post.html
-
-    and replaced the disquss code with the utterances code My actual title page
-    contains got each post is the title followed by " | David Budzynski's Blog",
-    so to make github issues title cleaner, I decided to remove the main title
-    of the blog  and prepend it with "Comments: " so it looks nicer and it more
-    intuitive to me.
-
-    If you do not want to have the _layouts/post.html file, you can just add the
-    ruby code to add comments to the bottom of each post. I think it's better to
-    have the _layouts/post.html file because it's cleaner and more organized,
-    but removing it is an option.
- -->
+<!--
+    Utterances comments (GitHub issues based). Uses pathname so renaming a
+    post title does not orphan its comment thread.
+    See https://utteranc.es/
+-->
 <script
   src="https://utteranc.es/client.js"
   repo="davidbudzynski/davidbudzynski.github.io"
-  issue-term="{{ include.issue-term | default: site.utterances.issue-term | default: 'title' }}"
+  issue-term="{{ include.issue-term | default: site.utterances.issue-term | default: 'pathname' }}"
   label="comment"
   theme="{{ include.theme | default: site.utterances.theme | default: 'github-light' }}"
   crossorigin="anonymous"
   async
 ></script>
+<noscript>
+  <p>
+    Comments require JavaScript. You can also comment via
+    <a href="https://github.com/davidbudzynski/davidbudzynski.github.io/issues">GitHub issues</a>.
+  </p>
+</noscript>
diff --git a/_layouts/home.html b/_layouts/home.html
new file mode 100644
index 0000000..6752e66
--- /dev/null
+++ b/_layouts/home.html
@@ -0,0 +1,47 @@
+---
+layout: default
+---
+
+<!--
+  Override of minima 2.5.1's home.html (github-pages pinned).
+  Only change: the preview under each post prefers the hand-written
+  `description` front matter (a 1-2 sentence teaser) and falls back to
+  the auto excerpt, so drafts and posts without a description still
+  render something. If minima is ever upgraded, diff against the new
+  theme's home.html.
+-->
+
+<div class="home">
+  {%- if page.title -%}
+    <h1 class="page-heading">{{ page.title }}</h1>
+  {%- endif -%}
+
+  {{ content }}
+
+  {%- if site.posts.size > 0 -%}
+    <h2 class="post-list-heading">{{ page.list_title | default: "Posts" }}</h2>
+    <ul class="post-list">
+      {%- for post in site.posts -%}
+      <li>
+        {%- assign date_format = site.minima.date_format | default: "%b %-d, %Y" -%}
+        <span class="post-meta">{{ post.date | date: date_format }}</span>
+        <h3>
+          <a class="post-link" href="{{ post.url | relative_url }}">
+            {{ post.title | escape }}
+          </a>
+        </h3>
+        {%- if site.show_excerpts -%}
+          {%- if post.description -%}
+            <p>{{ post.description | escape }}</p>
+          {%- else -%}
+            {{ post.excerpt }}
+          {%- endif -%}
+        {%- endif -%}
+      </li>
+      {%- endfor -%}
+    </ul>
+
+    <p class="rss-subscribe">subscribe <a href="{{ "/feed.xml" | relative_url }}">via RSS</a></p>
+  {%- endif -%}
+
+</div>
diff --git a/_layouts/post.html b/_layouts/post.html
index 2d7ea18..3fa5129 100644
--- a/_layouts/post.html
+++ b/_layouts/post.html
@@ -47,11 +47,46 @@ <h1 class="post-title p-name" itemprop="name headline">
 
   <div class="post-content e-content" itemprop="articleBody">{{ content }}</div>
 
-  {%- assign issue-term = page.title |
-    remove: " | David Budzyński" |
-    prepend: 'Comments: ' -%} 
-    
-  {% include utterances.html issue-term=issue-term %}
+  <nav class="post-nav" aria-label="Post navigation">
+    <div>
+      {% if page.previous %}
+      <span>← Older:</span>
+      <a href="{{ page.previous.url | relative_url }}">{{ page.previous.title | escape }}</a>
+      {% endif %}
+    </div>
+    <div>
+      {% if page.next %}
+      <span>Newer →:</span>
+      <a href="{{ page.next.url | relative_url }}">{{ page.next.title | escape }}</a>
+      {% endif %}
+    </div>
+  </nav>
+
+  {% assign related_count = 0 %}
+  <div class="related-posts">
+    <h2>Related posts</h2>
+    <ul>
+      {% for p in site.posts %}
+        {% if p.url != page.url and related_count < 3 %}
+          {% assign common = 0 %}
+          {% for tag in p.tags %}
+            {% if page.tags contains tag %}
+              {% assign common = common | plus: 1 %}
+            {% endif %}
+          {% endfor %}
+          {% if common > 0 %}
+            <li><a href="{{ p.url | relative_url }}">{{ p.title | escape }}</a></li>
+            {% assign related_count = related_count | plus: 1 %}
+          {% endif %}
+        {% endif %}
+      {% endfor %}
+      {% if related_count == 0 %}
+        <li><a href="{{ "/archive/" | relative_url }}">Browse the archive</a></li>
+      {% endif %}
+    </ul>
+  </div>
+
+  {% include utterances.html issue-term="pathname" %}
 
   <a class="u-url" href="{{ page.url | relative_url }}" hidden></a>
 </article>
diff --git a/_posts/2021-10-25-two-years-in-linux.md b/_posts/2021-10-25-two-years-in-linux.md
index 47d4913..3ff25b9 100644
--- a/_posts/2021-10-25-two-years-in-linux.md
+++ b/_posts/2021-10-25-two-years-in-linux.md
@@ -1,9 +1,11 @@
 ---
-layout   : post
+layout : post
 title    : "Two years in Linux"
 date     :   2021-10-25 21:50
-category : general
 tags     : [Linux, Hardware]
+description: "What two years of daily-driving Linux taught me after a lifetime of Windows — from a beer-fried laptop to a custom-built PC."
+redirect_from:
+  - /general/2021/10/25/two-years-in-linux.html
 ---
 
 ## Interactions with other operating systems
@@ -19,6 +21,8 @@ I was happy, although I became more aware about embedded telemetry and privacy
 concerns expressed by other people on the Internet around the time when Windows
 10 was announced.
 
+<!--more-->
+
 Around that time I also bought my first iPhone and I immediately fell in love
 with it. I decided to try out one of the iMacs in the university library and I
 decided to give a hackintosh route a try. Somehow I managed to get it installed
diff --git a/_posts/2022-04-23-r-native-placeholder.md b/_posts/2022-04-23-r-native-placeholder.md
index 47f931e..8761e6c 100644
--- a/_posts/2022-04-23-r-native-placeholder.md
+++ b/_posts/2022-04-23-r-native-placeholder.md
@@ -1,15 +1,19 @@
 ---
-layout   : post
+layout : post
 title    : "R 4.2.0 Native Placeholder"
 date     :   2022-04-23 21:00
-category : general
-tags     : R
+tags     : [R]
+description: "R 4.2.0 improved the native pipe and introduced the underscore placeholder — what it does and how it compares to magrittr."
+redirect_from:
+  - /general/2022/04/23/r-native-placeholder.html
 ---
 
 Yesterday (that is on April 22, 2022) R 4.2.0 was released and among
 other things, this release brought major improvements when using the
 native pipe operator (`|>`).
 
+<!--more-->
+
 You might be wondering: what is the native pipe anyways? Well, it's the
 base equivalent of `%>%` pipe from the `magrittr` package, heavily
 endorsed and used across `tidyverse` packages. It pipes a value forward
diff --git a/_posts/2024-03-10-split-keyboard.md b/_posts/2024-03-10-split-keyboard.md
index 3bdcf0b..5c421d9 100644
--- a/_posts/2024-03-10-split-keyboard.md
+++ b/_posts/2024-03-10-split-keyboard.md
@@ -1,12 +1,14 @@
 ---
-layout   : post
+layout : post
 title    : "Split Ergonomic Keyboards and Touch Typing"
 date     : 2024-03-10 10:00
-category : general
-tags     : Hardware
+tags     : [Hardware]
+description: "After hand fatigue from long typing days, I switched to a Cantor split ergonomic keyboard and relearned touch typing — here is what changed."
+redirect_from:
+  - /general/2024/03/10/split-keyboard.html
 ---
 
-![Cantor split keyboard left side](/assets/images/IMG_20240310_073808.jpg)
+![Cantor split keyboard left side](/assets/images/IMG_20240310_073808.jpg){: loading="lazy" }
 
 In July last year I started thinking about getting an ergonomic split keyboard.
 Many people choose to get a split keyboard because they are more comfortable to
@@ -19,6 +21,8 @@ about split keyboards before, but I had never really considered them. I thought
 that they would be very complicated to put together and too much trouble
 overall.
 
+<!--more-->
+
 I started to do some research and I found that there were many different types
 of split keyboards, some of them were very expensive and required many parts,
 and some of them were very cheap (relatively speaking), designed specifically to
@@ -86,7 +90,7 @@ The entire build process took me about 6 hours. Fortunately, Cantor's build
 guide is very straightforward and easy to follow. Once you do one part, the
 other one is much easier.
 
-![Cantor split keyboard right side](/assets/images/IMG_0173.JPG)
+![Cantor split keyboard right side](/assets/images/IMG_0173.JPG){: loading="lazy" }
 
 ### Flashing the firmware
 
@@ -127,13 +131,13 @@ into your computer and use the GUI or a chromium-based browser
 After few trials and errors, I ended up with a layout that I was happy with. It
 looks like this (each picture is a different layer):
 
-![keyboard layout layer zero](/assets/images/2024-03-09_15-56_keeb-layout-layer-0.png)
+![keyboard layout layer zero](/assets/images/2024-03-09_15-56_keeb-layout-layer-0.png){: loading="lazy" }
 
-![keyboard layout layer one](/assets/images/2024-03-09_16-02-keyboard-layout-layer-1.png)
+![keyboard layout layer one](/assets/images/2024-03-09_16-02-keyboard-layout-layer-1.png){: loading="lazy" }
 
-![keyboard layout layer one](/assets/images/2024-03-09_16-03-keyboard-layout-layer-2.png)
+![keyboard layout layer two](/assets/images/2024-03-09_16-03-keyboard-layout-layer-2.png){: loading="lazy" }
 
-![keyboard layout layer one](/assets/images/2024-03-09_16-04-keyboard-layout-layer-3.png)
+![keyboard layout layer three](/assets/images/2024-03-09_16-04-keyboard-layout-layer-3.png){: loading="lazy" }
 
 ## Learning to touch type
 
@@ -158,7 +162,7 @@ doing these exercises now because I feel like typing on this keyboard is
 actually more comfortable than on a traditional one. Here is the graph of my
 progress. It took me about two months to get to 40 words per minute.
 
-![typing speed graph](/assets/images/2024-03-09_18-31-typing-overall.png)
+![typing speed graph](/assets/images/2024-03-09_18-31-typing-overall.png){: loading="lazy" }
 
 ## Conclusions
 
diff --git a/_posts/2024-04-15-cpp-notebooks-org-mode.md b/_posts/2024-03-15-cpp-notebooks-org-mode.md
similarity index 93%
rename from _posts/2024-04-15-cpp-notebooks-org-mode.md
rename to _posts/2024-03-15-cpp-notebooks-org-mode.md
index 4512167..55b4c1b 100644
--- a/_posts/2024-04-15-cpp-notebooks-org-mode.md
+++ b/_posts/2024-03-15-cpp-notebooks-org-mode.md
@@ -2,7 +2,8 @@
 layout : post
 title  : "C++ Notebooks in Emacs' Org Mode"
 date   : 2024-03-15 19:00
-tags   : [Emacs, org-mode, C++, Software]
+tags   : [Emacs, Org-Mode, C++, Software]
+description: "Writing C++ documentation as executable notebooks in Emacs Org mode for readers coming from other languages."
 ---
 
 I recently had to write some documentation for people who are not familiar with
@@ -11,6 +12,8 @@ inside notebooks. I thought to myself that org mode could be a good tool for
 this, as it can compile the code and put the output right next to it in an HTML
 or PDF format.
 
+<!--more-->
+
 ## What is Org Mode
 
 [Org mode][1] is a major mode for [GNU Emacs][2]. It is used for keeping notes,
diff --git a/_posts/2024-04-13-firefox-customization.md b/_posts/2024-04-13-firefox-customization.md
index 9c2d2d0..f60bb39 100644
--- a/_posts/2024-04-13-firefox-customization.md
+++ b/_posts/2024-04-13-firefox-customization.md
@@ -1,9 +1,11 @@
 ---
-layout   : post
+layout : post
 title    : "Why I use Firefox as my default browser"
 date     : 2024-04-13 18:00
-category : general
 tags     : [Web, Software, Privacy]
+description: "Why Firefox is still my default browser: speed, customization, and privacy without Big Tech lock-in."
+redirect_from:
+  - /general/2024/04/13/firefox-customization.html
 ---
 
 ## Firefox's popularity around 2010's
@@ -17,6 +19,8 @@ Fast forward to 2024, and Firefox's usage has been declining for years and years
 and its users are often seen as a dying breed. But I still use Firefox as my
 default browser. Why?
 
+<!--more-->
+
 ## Customization
 
 Firefox is still the most customizable browser out there. You can change almost
diff --git a/_posts/2024-04-20-why-r-is-a-terrible-language.md b/_posts/2024-04-20-why-r-is-a-terrible-language.md
index 601aa44..213c366 100644
--- a/_posts/2024-04-20-why-r-is-a-terrible-language.md
+++ b/_posts/2024-04-20-why-r-is-a-terrible-language.md
@@ -2,7 +2,8 @@
 layout : post
 title  : "R is a Terrible Programming Language"
 date   : 2024-04-20 13:05
-tags   : [R, Software, Data Science] 
+tags   : [R, Software, Data Science]
+description: "A long-time R user's honest critique of R as a programming language — and what keeps me using it anyway."
 ---
 
 Recently I have been contemplating about how I feel about R as a programming
@@ -10,6 +11,8 @@ language. Even though I have been using it for many years now, I have never been
 able to shake the feeling that apart from several nice packages, R is an
 inferior language.
 
+<!--more-->
+
 Over the years there have been many criticisms of R, some of them are valid,
 like the [R Inferno book][1], some of them are not, like many medium articles by
 freshman year data science students who just discovered Python and R. More
diff --git a/_posts/2024-11-17-cli-file-managers.md b/_posts/2024-11-17-cli-file-managers.md
index 24e6ade..d8046a1 100644
--- a/_posts/2024-11-17-cli-file-managers.md
+++ b/_posts/2024-11-17-cli-file-managers.md
@@ -3,6 +3,7 @@ layout : post
 title  : "Program Spotlight: CLI File Managers (Yazi & Midnight Commander)"
 date   : 2024-11-17 17:00
 tags   : [Software]
+description: "Yazi vs Midnight Commander: two very different CLI file managers and where each one shines."
 ---
 
 While graphical file managers dominate desktop workflows, **command-line
@@ -11,6 +12,8 @@ system administrators, and command-line enthusiasts. They offer unparalleled
 speed, flexibility, and efficiency, particularly in environments where graphical
 user interfaces are unavailable or unnecessary.
 
+<!--more-->
+
 Among the diverse options available, **Yazi** and **Midnight Commander (MC)**
 stand out as two of the most interesting choices for very different reasons. In
 this article, we’ll explore their features and delve into why **Midnight
@@ -32,7 +35,7 @@ unique advantages, such as:
 
 ## Yazi: Sleek and Modern with a Familiar Twist
 
-![Yazi](/assets/images/2024-11-17_16-53-yazi.png)
+![Yazi file manager screenshot](/assets/images/2024-11-17_16-53-yazi.png){: loading="lazy" }
 
 **Yazi** is a relatively new CLI file manager that has quickly gained attention
 for its minimalistic yet powerful design. It combines traditional CLI speed with
@@ -67,7 +70,7 @@ through directories and preview files or pictures without opening them.
 
 ## Midnight Commander: A Timeless Workhorse
 
-![Midnight Commander](/assets/images/2024-11-17_16-54-mc.png)
+![Midnight Commander screenshot](/assets/images/2024-11-17_16-54-mc.png){: loading="lazy" }
 
 **Midnight Commander (MC)** has stood the test of time, remaining a favorite
 among CLI enthusiasts for decades. With its **dual-pane interface**, extensive
diff --git a/_posts/2024-11-20-docker-for-R.md b/_posts/2024-11-20-docker-for-R.md
index 45a36fb..a4df6ec 100644
--- a/_posts/2024-11-20-docker-for-R.md
+++ b/_posts/2024-11-20-docker-for-R.md
@@ -3,6 +3,7 @@ layout : post
 title  : "Docker for R projects"
 date   : 2024-11-20 18:08
 tags   : [R, Docker, Reproducibility, Software]
+description: "A practical intro to Docker for R projects: reproducible environments, collaboration, and when containers pay off."
 ---
 
 For years, R users have been known for their knack for analytical thinking, not
@@ -13,6 +14,8 @@ ggplots. But as the complexity of data science workflows has grown, the ability
 to manage environments, ensure reproducibility, and collaborate effectively has
 become critical. That’s where Docker comes in.
 
+<!--more-->
+
 At its core, Docker is a platform that helps you package and run applications in
 isolated environments called containers. A container is like a virtual box that
 holds everything your R project needs to run—R itself, libraries, system
diff --git a/_posts/2024-11-21-mini-pc.md b/_posts/2024-11-21-mini-pc.md
index 4a9efbe..faa9a48 100644
--- a/_posts/2024-11-21-mini-pc.md
+++ b/_posts/2024-11-21-mini-pc.md
@@ -3,6 +3,7 @@ layout : post
 title  :  "Mini PC: a Viable Desktop Replacement in 2024"
 date   :   2024-11-21 08:50
 tags   : [Hardware, Mini PC]
+description: "After testing a mini PC as a TV-box replacement, why I think small-form-factor desktops are viable daily drivers."
 ---
 
 Several months ago I started looking for something that would replace the
@@ -12,6 +13,8 @@ great alternative to traditional desktops and laptops. They are powerful,
 portable, and affordable. In this post, I will discuss the benefits of mini PCs
 and why you should consider getting one.
 
+<!--more-->
+
 ## What is a mini pc
 
 Mini PCs are small form factor computers that are designed to be compact. They
diff --git a/_posts/2024-03-13-program-spotlight-rclone.md b/_posts/2026-08-15-program-spotlight-rclone.md
similarity index 98%
rename from _posts/2024-03-13-program-spotlight-rclone.md
rename to _posts/2026-08-15-program-spotlight-rclone.md
index d03bae4..349f87f 100644
--- a/_posts/2024-03-13-program-spotlight-rclone.md
+++ b/_posts/2026-08-15-program-spotlight-rclone.md
@@ -2,7 +2,8 @@
 layout : post
 title  : "Program Spotlight: Rclone"
 date   : 2026-08-15 10:00
-tags   : [Software, backup, cloud, photography]
+tags   : [Software, Backup, Cloud, Photography]
+description: "Rclone is rsync for cloud storage — plus my favourite offline use case: ingesting photos and videos from a camera."
 ---
 
 **Rclone** is one of those command-line tools that you don't realize you need
@@ -11,6 +12,8 @@ to and from cloud storage, often described as "rsync for cloud storage". It
 supports dozens of providers like Google Drive, OneDrive, Dropbox, and
 S3-compatible storage.
 
+<!--more-->
+
 But my favourite use case for rclone has nothing to do with the cloud at all.
 It's copying photos and videos from a camera to my computer — and doing it
 reliably, which a simple drag and drop often isn't.
diff --git a/_posts/2026-09-01-renv-vs-docker.md b/_posts/2026-09-01-renv-vs-docker.md
index dd0ebb5..d5068c4 100644
--- a/_posts/2026-09-01-renv-vs-docker.md
+++ b/_posts/2026-09-01-renv-vs-docker.md
@@ -3,6 +3,7 @@ layout : post
 title  : "renv vs Docker: when to use each"
 date   : 2026-09-01 10:00
 tags   : [R, Docker, Reproducibility]
+description: "renv and Docker solve different halves of reproducibility — when each is enough and when you need both."
 ---
 
 A while back I wrote about [Docker for R projects][5], and the most common
@@ -13,6 +14,8 @@ problem, and knowing which half you need saves a lot of frustration. In this
 post I want to compare the two tools directly and give some practical guidance
 on when each is the right choice.
 
+<!--more-->
+
 ## What renv locks down
 
 renv works at the **package level**. It gives every project its own private
diff --git a/_posts/2026-09-08-quarto-vs-jupyter.md b/_posts/2026-09-08-quarto-vs-jupyter.md
index 6f28946..620803e 100644
--- a/_posts/2026-09-08-quarto-vs-jupyter.md
+++ b/_posts/2026-09-08-quarto-vs-jupyter.md
@@ -3,6 +3,7 @@ layout : post
 title  : "Quarto for reproducible reports vs Jupyter"
 date   : 2026-09-08 10:00
 tags   : [Quarto, Jupyter, Reproducibility, Data Science]
+description: "Notebooks are great sketchpads and terrible deliverables — why Quarto's plain-text, render-from-clean-state documents beat Jupyter for anything meant to be read."
 ---
 
 Some time ago I wrote about running [C++ notebooks in Emacs' Org mode][3]. That
@@ -13,6 +14,8 @@ results, and prose. In this post I want to apply that same argument to everyday
 data science work and compare [Jupyter][2] notebooks with [Quarto][1] documents
 for anything that deserves to be called a *report*.
 
+<!--more-->
+
 ## The notebook problem
 
 I like Jupyter. For poking at an unfamiliar dataset it is hard to beat: run a
@@ -104,6 +107,6 @@ they are just not the thing I hand over at the end.
 
 [1]: https://quarto.org/
 [2]: https://jupyter.org/
-[3]: https://davidbudzynski.github.io/2024/04/15/cpp-notebooks-org-mode.html
+[3]: {% post_url 2024-03-15-cpp-notebooks-org-mode %}
 [4]: https://rmarkdown.rstudio.com/
 [5]: https://pandoc.org/
diff --git a/_posts/2026-09-15-python-data-work-without-jupyter.md b/_posts/2026-09-15-python-data-work-without-jupyter.md
index d7bd0c4..9cb2f4f 100644
--- a/_posts/2026-09-15-python-data-work-without-jupyter.md
+++ b/_posts/2026-09-15-python-data-work-without-jupyter.md
@@ -3,6 +3,7 @@ layout : post
 title  : "Writing Python for data work without Jupyter"
 date   : 2026-09-15 10:00
 tags   : [Python, Data Science]
+description: "After years of R Markdown and Makefiles, Jupyter never grew on me — the plain-text Python workflow I use instead, from REPL to scripts an AI agent can actually read."
 ---
 
 When I moved most of my work from R to Python, everyone assumed I would live in
@@ -15,6 +16,8 @@ version control, and these days plain text files are something my AI coding
 agent can actually work with — which matters to me quite a lot. This post is the
 workflow I use instead, and why I think notebooks have lost their advantage.
 
+<!--more-->
+
 ## Exploration: the REPL is enough
 
 The first thing people reach for in a notebook is interactivity: run something,
diff --git a/_posts/2026-09-22-handwritten-notes-fountain-pen.md b/_posts/2026-09-22-handwritten-notes-fountain-pen.md
index 768f93f..a8ce909 100644
--- a/_posts/2026-09-22-handwritten-notes-fountain-pen.md
+++ b/_posts/2026-09-22-handwritten-notes-fountain-pen.md
@@ -3,6 +3,7 @@ layout : post
 title  : "Why I still write by hand"
 date   : 2026-09-22 10:00
 tags   : [Productivity, Writing, Tooling]
+description: "In a world of AI meeting transcripts nobody reads, why a fountain pen and two-thirds of a page still wins for thinking."
 ---
 
 In a corporate world every meeting now comes with an AI aide that happily spits
@@ -10,6 +11,8 @@ out four pages of transcript-flavoured "notes" nobody will ever read. I go the
 other way: a fountain pen, decent ink, good paper, and two thirds of a page
 that is actually useful.
 
+<!--more-->
+
 This comes from a long-time Org mode user, not a pen-and-paper romantic. For
 many years I kept my work notes in Org mode and I still think it is great. But
 after moving jobs I ran into the usual corporate friction: different
@@ -98,7 +101,7 @@ hold on to. The pen gives you two thirds of a page you actually thought about
 
 [1]: https://doi.org/10.1007/s10648-024-09914-w
 [2]: {% post_url 2024-03-10-split-keyboard %}
-[3]: {% post_url 2024-04-15-cpp-notebooks-org-mode %}
+[3]: {% post_url 2024-03-15-cpp-notebooks-org-mode %}
 [4]: https://www.lamy.com/en-us/p/lamy-safari-fountain-pen
 [5]: https://www.pilot-custom.jp/en/
 [6]: https://platinumpenusa.com/luxury-writing/3776-collection/
diff --git a/about.md b/about.md
index 0462045..a18f561 100644
--- a/about.md
+++ b/about.md
@@ -19,3 +19,6 @@ keyboards to CLI file managers.
 I'm easy to reach on [GitHub](https://github.com/davidbudzynski). If a post is
 wrong, outdated, or just badly worded, the comments below each article are the
 best place to tell me.
+
+You can browse the [archive](/archive/) and [tags](/tags/), see what I
+[maintain](/projects/), or follow along [via RSS](/feed.xml).
diff --git a/archive.md b/archive.md
new file mode 100644
index 0000000..f8deb2b
--- /dev/null
+++ b/archive.md
@@ -0,0 +1,22 @@
+---
+layout: page
+title: Archive
+permalink: /archive/
+description: "All posts by year."
+---
+
+All posts, newest first. See also [Tags](/tags/).
+
+{% assign posts_by_year = site.posts | group_by_exp: "post", "post.date | date: '%Y'" %}
+{% for year in posts_by_year %}
+## {{ year.name }}
+
+<ul>
+  {% for post in year.items %}
+  <li>
+    <span>{{ post.date | date: "%b %-d" }}</span> —
+    <a href="{{ post.url | relative_url }}">{{ post.title | escape }}</a>
+  </li>
+  {% endfor %}
+</ul>
+{% endfor %}
diff --git a/index.markdown b/index.markdown
index 0671507..7c68c45 100644
--- a/index.markdown
+++ b/index.markdown
@@ -4,3 +4,8 @@
 
 layout: home
 ---
+
+I write about R and Python workflows, reproducible environments, Linux
+tooling, and self-hosting. Start with the [About](/about/) page, browse by
+[Tags](/tags/) or [Archive](/archive/), [search](/search/) the posts, or
+follow along [via RSS](/feed.xml).
diff --git a/search.json b/search.json
new file mode 100644
index 0000000..ad79ece
--- /dev/null
+++ b/search.json
@@ -0,0 +1,14 @@
+---
+layout: null
+---
+[
+  {% for post in site.posts %}
+  {
+    "title": {{ post.title | jsonify }},
+    "url": {{ post.url | relative_url | jsonify }},
+    "date": {{ post.date | date: "%Y-%m-%d" | jsonify }},
+    "tags": {{ post.tags | jsonify }},
+    "description": {{ post.description | default: post.excerpt | strip_html | strip_newlines | truncate: 160 | jsonify }}
+  }{% unless forloop.last %},{% endunless %}
+  {% endfor %}
+]
diff --git a/search.md b/search.md
new file mode 100644
index 0000000..eb129cc
--- /dev/null
+++ b/search.md
@@ -0,0 +1,57 @@
+---
+layout: page
+title: Search
+permalink: /search/
+description: "Search posts by title, tag, or description."
+---
+
+<input type="search" id="search-input" placeholder="Type to filter posts…" aria-label="Search posts" style="width: 100%; padding: 0.5em;" />
+
+<ul id="search-results"></ul>
+<p id="search-count" aria-live="polite"></p>
+
+<script>
+(function () {
+  var input = document.getElementById('search-input');
+  var results = document.getElementById('search-results');
+  var count = document.getElementById('search-count');
+  var posts = [];
+
+  function render(query) {
+    var q = query.trim().toLowerCase();
+    results.innerHTML = '';
+    if (!q) {
+      count.textContent = posts.length + ' posts. Start typing to filter.';
+      return;
+    }
+    var matches = posts.filter(function (p) {
+      return (p.title + ' ' + p.tags.join(' ') + ' ' + p.description)
+        .toLowerCase().indexOf(q) !== -1;
+    });
+    count.textContent = matches.length + ' match' + (matches.length === 1 ? '' : 'es') + '.';
+    matches.slice(0, 30).forEach(function (p) {
+      var li = document.createElement('li');
+      var a = document.createElement('a');
+      a.href = p.url;
+      a.textContent = p.title;
+      li.appendChild(a);
+      var span = document.createElement('span');
+      span.textContent = ' — ' + p.date;
+      li.appendChild(span);
+      results.appendChild(li);
+    });
+  }
+
+  fetch('{{ "/search.json" | relative_url }}')
+    .then(function (r) { return r.json(); })
+    .then(function (data) {
+      posts = data;
+      render('');
+    })
+    .catch(function () {
+      count.textContent = 'Search index could not be loaded.';
+    });
+
+  input.addEventListener('input', function () { render(input.value); });
+})();
+</script>
diff --git a/tests/test_site.rb b/tests/test_site.rb
new file mode 100644
index 0000000..fed1a3a
--- /dev/null
+++ b/tests/test_site.rb
@@ -0,0 +1,386 @@
+# frozen_string_literal: true
+
+# Static regression tests for the Jekyll blog.
+#
+# Stdlib only (minitest + yaml) so they run with any working Ruby and no
+# `bundle install`:
+#
+#   ruby -Itests tests/test_site.rb
+#
+# They validate front matter consistency, config hardening, navigation
+# pages, and internal links without needing a Jekyll build.
+
+require "minitest/autorun"
+require "yaml"
+require "date"
+require "set"
+
+ROOT = File.expand_path("..", __dir__)
+POSTS_DIR = File.join(ROOT, "_posts")
+DRAFTS_DIR = File.join(ROOT, "_drafts")
+
+def read_file(path)
+  File.read(path, encoding: "utf-8")
+end
+
+# Returns [front_matter_hash, body_string] using a real YAML parser.
+def parse_front_matter(text)
+  lines = text.lines
+  return [{}, text] unless lines.first&.strip == "---"
+
+  closing = lines[1..].index { |line| line.strip == "---" }
+  return [{}, text] if closing.nil?
+
+  fm_text = lines[1, closing].join
+  body = lines[(closing + 2)..]&.join.to_s
+  data = YAML.safe_load(fm_text, permitted_classes: [Date, Time, DateTime]) || {}
+  [data, body]
+end
+
+# Front-matter dates may parse to String, Date, Time, or DateTime.
+# Normalizes all of them to "YYYY-MM-DD".
+def front_date_prefix(value)
+  if value.respond_to?(:strftime)
+    value.strftime("%Y-%m-%d")
+  else
+    value.to_s[0, 10]
+  end
+end
+
+def post_files
+  Dir.children(POSTS_DIR).select { |f| f.end_with?(".md") }.sort
+end
+
+def markdown_files(dir)
+  Dir.children(dir).select { |f| f.end_with?(".md") }.sort
+end
+
+class ConfigTest < Minitest::Test
+  def setup
+    @config = read_file(File.join(ROOT, "_config.yml"))
+  end
+
+  def test_lang
+    assert_includes @config, "lang: en-GB"
+  end
+
+  def test_timezone_uk
+    assert_includes @config, "timezone: Europe/London"
+  end
+
+  def test_permalink_has_no_categories
+    permalink = @config[/^permalink:\s*(.+)$/, 1]
+    refute_nil permalink, "permalink must be explicit"
+    refute_includes permalink, ":categories"
+    assert_includes permalink, ":year"
+    assert_includes permalink, ":title"
+  end
+
+  def test_future_posts_stay_hidden
+    assert_match(/^future:\s*false/, @config)
+  end
+
+  def test_excerpts
+    assert_includes @config, "excerpt_separator:"
+    assert_includes @config, "show_excerpts: true"
+  end
+
+  def test_header_pages
+    %w[about.md projects.md archive.md tags.html search.md].each do |page|
+      assert_includes @config, page, "header_pages missing #{page}"
+    end
+  end
+
+  def test_plugins
+    %w[jekyll-feed jekyll-sitemap jekyll-seo-tag jekyll-redirect-from].each do |plugin|
+      assert_includes @config, plugin, "plugin missing: #{plugin}"
+    end
+  end
+
+  def test_minima_skin
+    assert_includes @config, "skin: auto"
+  end
+
+  def test_url
+    assert_includes @config, "https://davidbudzynski.github.io"
+  end
+
+  def test_tests_dir_excluded_from_build
+    assert_includes @config, "tests/"
+  end
+end
+
+class PostFrontMatterTest < Minitest::Test
+  def test_all_posts
+    files = post_files
+    assert_operator files.length, :>=, 10, "expected at least 10 posts"
+    files.each { |fname| check_post(fname) }
+  end
+
+  def check_post(fname)
+    ctx = "post #{fname}"
+    assert_match(/^\d{4}-\d{2}-\d{2}-.+\.md$/, fname,
+      "#{ctx}: filename must be YYYY-MM-DD-slug.md")
+    fm, = parse_front_matter(read_file(File.join(POSTS_DIR, fname)))
+    assert_equal "post", fm["layout"], "#{ctx}: layout must be post"
+    assert fm["title"] && !fm["title"].to_s.empty?, "#{ctx}: title is required"
+    assert fm["date"], "#{ctx}: date is required"
+    # Filename date must match front-matter date (prevents URL confusion).
+    assert_equal fname[0, 10], front_date_prefix(fm["date"]),
+      "#{ctx}: filename date != front-matter date"
+    # Tags must be a non-empty list (never a bare string).
+    tags = fm["tags"]
+    assert_kind_of Array, tags, "#{ctx}: tags must be a YAML list like [R]"
+    refute_empty tags, "#{ctx}: tags must not be empty"
+    tags.each do |tag|
+      assert !tag.to_s.strip.empty?, "#{ctx}: tags must not contain blanks"
+    end
+    lowered = tags.map { |t| t.to_s.downcase }
+    assert_equal lowered.uniq.length, tags.length, "#{ctx}: duplicate tags"
+    # Legacy single-category URLs are gone; permalink is explicit.
+    refute fm.key?("category"), "#{ctx}: use tags, not category"
+    refute fm.key?("categories"), "#{ctx}: use tags, not categories"
+    # SEO description required.
+    desc = fm["description"]
+    assert_kind_of String, desc, "#{ctx}: description is required"
+    assert_operator desc.length, :>=, 20,
+      "#{ctx}: description should be a full sentence (20+ chars)"
+  end
+
+  def test_legacy_category_urls_preserved
+    expected = {
+      "2021-10-25-two-years-in-linux.md" => "/general/2021/10/25/two-years-in-linux.html",
+      "2022-04-23-r-native-placeholder.md" => "/general/2022/04/23/r-native-placeholder.html",
+      "2024-03-10-split-keyboard.md" => "/general/2024/03/10/split-keyboard.html",
+      "2024-04-13-firefox-customization.md" => "/general/2024/04/13/firefox-customization.html"
+    }
+    expected.each do |fname, old_url|
+      fm, = parse_front_matter(read_file(File.join(POSTS_DIR, fname)))
+      assert_kind_of Array, fm["redirect_from"], "#{fname}: redirect_from required"
+      assert_includes fm["redirect_from"], old_url, fname
+    end
+  end
+
+  def test_renamed_files_match_front_matter
+    assert File.exist?(File.join(POSTS_DIR, "2026-08-15-program-spotlight-rclone.md"))
+    assert File.exist?(File.join(POSTS_DIR, "2024-03-15-cpp-notebooks-org-mode.md"))
+    refute File.exist?(File.join(POSTS_DIR, "2024-03-13-program-spotlight-rclone.md"))
+    refute File.exist?(File.join(POSTS_DIR, "2024-04-15-cpp-notebooks-org-mode.md"))
+  end
+end
+
+class ExcerptMarkerTest < Minitest::Test
+  # Every post/draft must contain the excerpt_separator marker.
+  # With a custom excerpt_separator, Jekyll uses the WHOLE article as the
+  # excerpt when the marker is missing — the home page then renders full
+  # articles instead of previews. These tests make that failure loud.
+  def check_dir(directory)
+    files = markdown_files(directory)
+    refute_empty files, "expected markdown files in #{directory}"
+    files.each do |fname|
+      _, body = parse_front_matter(read_file(File.join(directory, fname)))
+      assert_includes body, "<!--more-->",
+        "#{fname}: missing excerpt marker — home page would show full text"
+    end
+  end
+
+  def test_posts_have_markers
+    check_dir(POSTS_DIR)
+  end
+
+  def test_drafts_have_markers
+    check_dir(DRAFTS_DIR)
+  end
+end
+
+class PostImagesTest < Minitest::Test
+  IMG_RE = %r{!\[([^\]]*)\]\(([^)]+)\)}
+
+  def test_images_exist_lazy_and_descriptive
+    post_files.each do |fname|
+      text = read_file(File.join(POSTS_DIR, fname))
+      _, body = parse_front_matter(text)
+      alts = []
+      body.scan(IMG_RE) do |alt, src|
+        ctx = "post #{fname}, image #{src}"
+        assert_operator alt.strip.length, :>=, 4,
+          "#{ctx}: alt text must be descriptive"
+        alts << alt.strip.downcase
+        if src.start_with?("/assets/")
+          assert File.exist?(File.join(ROOT, src.delete_prefix("/"))),
+            "#{ctx}: missing image file"
+        end
+        line = body.each_line.find { |l| l.include?(src) }
+        assert_includes line, 'loading="lazy"',
+          "#{ctx}: image should lazy-load"
+      end
+      assert_equal alts.uniq.length, alts.length,
+        "#{fname}: duplicate alt text"
+    end
+  end
+end
+
+class PagesTest < Minitest::Test
+  def test_archive
+    fm, body = parse_front_matter(read_file(File.join(ROOT, "archive.md")))
+    assert_equal "/archive/", fm["permalink"]
+    assert_includes body, "group_by_exp"
+  end
+
+  def test_search_page
+    fm, body = parse_front_matter(read_file(File.join(ROOT, "search.md")))
+    assert_equal "/search/", fm["permalink"]
+    assert_includes body, "search.json"
+    assert_includes body, "search-input"
+  end
+
+  def test_search_index
+    fm, text = parse_front_matter(read_file(File.join(ROOT, "search.json")))
+    # `layout: null` parses to nil in real YAML — which is exactly what
+    # Jekyll wants for "no layout".
+    assert_nil fm["layout"]
+    assert_includes text, "site.posts"
+    assert_includes text, "post.description"
+  end
+
+  def test_tags_page
+    fm, = parse_front_matter(read_file(File.join(ROOT, "tags.html")))
+    assert_equal "/tags/", fm["permalink"]
+  end
+
+  def test_404_links_home_archive_tags
+    text = read_file(File.join(ROOT, "404.html"))
+    assert_includes text, '"/" | relative_url'
+    assert_includes text, "/archive/"
+    assert_includes text, "/tags/"
+  end
+
+  def test_home_intro_links
+    text = read_file(File.join(ROOT, "index.markdown"))
+    %w[/about/ /tags/ /archive/ /search/ /feed.xml].each do |link|
+      assert_includes text, link, "home missing link #{link}"
+    end
+  end
+
+  def test_about_crosslinks
+    text = read_file(File.join(ROOT, "about.md"))
+    %w[/archive/ /tags/ /projects/ /feed.xml].each do |link|
+      assert_includes text, link, "about missing link #{link}"
+    end
+  end
+end
+
+class LayoutsTest < Minitest::Test
+  def test_home_prefers_description_over_excerpt
+    text = read_file(File.join(ROOT, "_layouts", "home.html"))
+    assert_includes text, "post.description"
+    assert_includes text, "post.excerpt",
+      "home must fall back to excerpt when description missing"
+    assert_includes text, "post-list"
+    assert_includes text, "rss-subscribe"
+  end
+
+  def test_post_layout_nav_related_comments
+    text = read_file(File.join(ROOT, "_layouts", "post.html"))
+    assert_includes text, "page.previous"
+    assert_includes text, "page.next"
+    # Jekyll: site.posts is newest-first, so previous == older post,
+    # next == newer post. Labels must match that order.
+    prev_block = text.split("page.previous")[1].split("endif").first
+    assert_includes prev_block, "Older"
+    next_block = text.split("page.next")[1].split("endif").first
+    assert_includes next_block, "Newer"
+    assert_includes text, "Related posts"
+    assert_includes text, 'include utterances.html issue-term="pathname"'
+    refute_includes text, "prepend: 'Comments:"
+  end
+
+  def test_utterances_stable_and_accessible
+    text = read_file(File.join(ROOT, "_includes", "utterances.html"))
+    assert_includes text, "default: 'pathname'"
+    assert_includes text, "<noscript>"
+  end
+
+  def test_head_polish
+    text = read_file(File.join(ROOT, "_includes", "head.html"))
+    assert_includes text, "theme-color"
+    assert_includes text, "apple-touch-icon"
+  end
+end
+
+class LinksTest < Minitest::Test
+  def test_post_url_tags_resolve
+    slugs = post_files.map { |f| f[0...-3] }.to_set
+    pages = %w[projects.md about.md archive.md]
+    pages += post_files.map { |f| File.join("_posts", f) }
+    if Dir.exist?(DRAFTS_DIR)
+      pages += markdown_files(DRAFTS_DIR).map { |f| File.join("_drafts", f) }
+    end
+    pages.each do |page|
+      path = File.join(ROOT, page)
+      next unless File.exist?(path)
+
+      read_file(path).scan(/{%\s*post_url\s+(\S+)\s*%}/) do |(slug)|
+        slug = File.basename(slug.delete_prefix("'").delete_suffix("'")
+          .delete_prefix('"').delete_suffix('"'))
+        assert_includes slugs, slug, "#{page}: broken post_url #{slug}"
+      end
+    end
+  end
+
+  def test_no_ds_store
+    offenders = []
+    search_dirs = Dir.glob(File.join(ROOT, "**")).reject do |d|
+      d.include?("/.git/") || d.include?("/vendor/")
+    end
+    search_dirs.each do |dir|
+      next unless File.directory?(dir)
+
+      offenders << dir if File.exist?(File.join(dir, ".DS_Store"))
+    end
+    assert_empty offenders, ".DS_Store found in: #{offenders.join(', ')}"
+    assert_includes read_file(File.join(ROOT, ".gitignore")), ".DS_Store"
+  end
+end
+
+class LicenseTest < Minitest::Test
+  def test_license_gpl_for_code_cc_for_content
+    text = read_file(File.join(ROOT, "LICENSE.md"))
+    assert_includes text, "GNU GENERAL PUBLIC LICENSE"
+    assert_includes text, "Version 3"
+    assert_includes text, "David Budzyński"
+    assert_includes text, "code blocks",
+      "LICENSE must state that post code examples are GPLv3"
+    assert_includes text, "BY-NC-ND",
+      "prose and images must carry the CC BY-NC-ND grant"
+    assert_includes text, "creativecommons.org/licenses/by-nc-nd",
+      "LICENSE must link the CC deed"
+    refute_includes text, "Permission is hereby granted",
+      "code must not carry the MIT grant"
+  end
+
+  def test_footer_shows_rights_notice
+    text = read_file(File.join(ROOT, "_includes", "footer.html"))
+    assert_includes text, "BY-NC-ND"
+    assert_includes text, "LICENSE"
+  end
+
+  def test_readme_points_at_license
+    assert_includes read_file(File.join(ROOT, "README.md")), "LICENSE"
+  end
+end
+
+class DraftsTest < Minitest::Test
+  def test_drafts_have_basics
+    skip "no _drafts dir" unless Dir.exist?(DRAFTS_DIR)
+
+    files = markdown_files(DRAFTS_DIR)
+    refute_empty files, "expected drafts"
+    files.each do |fname|
+      fm, = parse_front_matter(read_file(File.join(DRAFTS_DIR, fname)))
+      assert_equal "post", fm["layout"], "draft #{fname}"
+      assert fm["title"] && !fm["title"].to_s.empty?, "draft #{fname}: title required"
+      assert_kind_of Array, fm["tags"], "draft #{fname}: tags must be a list"
+    end
+  end
+end