Typst: resolve CSS generic font families to an installed font

news/changelog-1.11.md

@@ -36,6 +36,7 @@ All changes included in 1.11:
 
 ### `typst`
 
+- ([#11683](https://github.com/quarto-dev/quarto-cli/issues/11683)): Fix `unknown font family` warnings, and wrong fonts, when a `font-family` list or brand typography uses a CSS generic family (`serif`, `sans-serif`, `monospace`, `cursive`, `fantasy`, `math`, `system-ui`, `ui-*`). Typst has no generic families, so each one is now replaced by the first installed font from a list of well-known candidates, and the keyword is no longer passed to Typst. No fonts are bundled.
 - ([#14847](https://github.com/quarto-dev/quarto-cli/pull/14847)): Fix `toc_title` auto-fallback in typst outline template that was ignoring the computed fallback value when `toc_title` is `none`.
 - ([#14947](https://github.com/quarto-dev/quarto-cli/issues/14947)): Fix Typst compilation failing with `invalid number suffix: px` when an image with alt text (`fig-alt`, `alt`, or an inline image caption) has its `width` or `height` in pixels. These images are now written by Pandoc's Typst writer like other images, which also fixes URL-encoded image paths and unsupported size units for them.
 

src/resources/filters/modules/typst_css.lua

@@ -658,11 +658,86 @@ end
 
 local _available_fonts = nil
 local _fonts_initialized = false
-local _generic_families = {
-  ["serif"] = true, ["sans-serif"] = true, ["monospace"] = true,
-  ["cursive"] = true, ["fantasy"] = true, ["math"] = true,
+
+-- Typst has no CSS generic families, so emitting `sans-serif` / `monospace` makes every compile warn
+-- `unknown font family`. Each generic keyword is instead replaced, at its
+-- position in the user's list, by the first *available* font from an ordered
+-- candidate list. The keyword itself is never emitted. No font is bundled.
+--
+-- Sources (fetched 2026-10-03), merged in this order per keyword:
+--   1. Chromium per-OS defaults (chrome/app/resources/locale_settings_{win,mac}.grd)
+--   2. fontconfig conf.d/60-latin.conf (Linux)
+--   3. Modern Font Stacks (github.com/system-fonts/modern-font-stacks, CC0)
+--   4. Bootstrap 5 $font-family-sans-serif / $font-family-monospace
+--   5. Typst's built-in fonts, last, so serif/monospace/math always resolve.
+-- Non-family tokens from those sources (sans-serif-condensed, casual, ...)
+-- are omitted. sans-serif has no built-in target and may resolve to nothing.
+local _generic_candidates = {
+  ["serif"] = {
+    "Times New Roman", "Times",
+    "Noto Serif", "DejaVu Serif", "Thorndale AMT", "Luxi Serif",
+    "Nimbus Roman No9 L", "Nimbus Roman",
+    "Charter", "Bitstream Charter", "Sitka Text", "Cambria", "Georgia",
+    "Libertinus Serif",
+  },
+  ["sans-serif"] = {
+    "Arial", "Helvetica",
+    "Noto Sans", "DejaVu Sans", "Verdana", "Albany AMT", "Luxi Sans",
+    "Nimbus Sans L", "Nimbus Sans", "Lucida Sans Unicode", "Tahoma",
+    "Inter", "Roboto", "Helvetica Neue", "Arial Nova", "Segoe UI",
+    "Liberation Sans", "Ubuntu", "Calibri",
+  },
+  ["monospace"] = {
+    "Courier New", "Menlo",
+    "Noto Sans Mono", "Inconsolata", "Andale Mono", "Cumberland AMT",
+    "Luxi Mono", "Nimbus Mono L", "Nimbus Mono", "Nimbus Mono PS", "Courier",
+    "Cascadia Code", "Source Code Pro", "Consolas",
+    "SFMono-Regular", "Monaco", "Liberation Mono",
+    "DejaVu Sans Mono",
+  },
+  ["cursive"] = {
+    "Comic Sans MS", "Apple Chancery",
+    "ITC Zapf Chancery Std", "Zapfino",
+    "Segoe Print", "Bradley Hand", "Chilanka",
+  },
+  ["fantasy"] = {
+    "Impact", "Papyrus",
+    "Copperplate Gothic Std", "Cooper Std", "Bauhaus Std",
+  },
+  ["math"] = {
+    "Cambria Math", "STIX Two Math",
+    "New Computer Modern Math",
+  },
 }
 
+local function concat_lists(...)
+  local out = {}
+  for _, l in ipairs({...}) do
+    for _, v in ipairs(l) do out[#out + 1] = v end
+  end
+  return out
+end
+
+-- CSS Fonts 4 `system-ui` / `ui-*`: platform UI faces first, then the plain
+-- generic they specialise (ui-rounded has no plain fallback).
+_generic_candidates["system-ui"] = concat_lists(
+  { "SF Pro Text", "SF Pro", "Segoe UI", "Cantarell", "Adwaita Sans",
+    "Noto Sans UI", "Ubuntu" },
+  _generic_candidates["sans-serif"])
+_generic_candidates["ui-sans-serif"] = _generic_candidates["system-ui"]
+_generic_candidates["ui-serif"] = concat_lists(
+  { "New York" }, _generic_candidates["serif"])
+_generic_candidates["ui-monospace"] = concat_lists(
+  { "SF Mono", "Cascadia Mono" }, _generic_candidates["monospace"])
+_generic_candidates["ui-rounded"] = {
+  "SF Pro Rounded", "Hiragino Maru Gothic ProN", "Arial Rounded MT Bold",
+  "Arial Rounded MT", "Quicksand", "Comfortaa", "Manjari",
+}
+
+-- Typst's default text font; the last resort when a list resolves to nothing,
+-- since Typst rejects an empty `font: ()`.
+local _terminal_fallback = "Libertinus Serif"
+
 local function init_available_fonts(list)
   _fonts_initialized = true
   if list == nil then
@@ -681,25 +756,58 @@ local function ensure_available_fonts()
   init_available_fonts(param('typst-available-fonts'))
 end
 
+-- Pure resolver: `families` is a list of unquoted CSS family names/keywords,
+-- `available` a set of lower-cased available family names (nil = unknown).
+-- Returns the list of concrete family names to hand to Typst.
+local function resolve_font_families(families, available)
+  local resolved, unavailable, seen = {}, {}, {}
+  local function add(into, name)
+    local k = name:lower()
+    if not seen[k] then
+      seen[k] = true
+      into[#into + 1] = name
+    end
+  end
+  for _, name in ipairs(families) do
+    local key = name:lower()
+    local candidates = _generic_candidates[key]
+    if candidates then
+      -- Without availability data there is no way to choose; drop it.
+      for _, c in ipairs(available and candidates or {}) do
+        if available[c:lower()] then
+          add(resolved, c)
+          break
+        end
+      end
+    elseif key:find('^generic%(') then
+      -- script-specific generics (fangsong, kai, ...) have no Typst analogue
+    elseif not available or available[key] then
+      add(resolved, name)
+    else
+      add(unavailable, name)
+    end
+  end
+  if #resolved > 0 then return resolved end
+  if #unavailable > 0 then return unavailable end
+  return { _terminal_fallback }
+end
+
 local function translate_font_family_list(sl)
   if sl == nil then
     return '()'
   end
   ensure_available_fonts()
-  local all_strings = {}
-  local filtered = {}
+  local families = {}
   for s in sl:gmatch('([^,]+)') do
     s = s:gsub('^%s+', ''):gsub('%s+$', '')
     if s ~= '' then
-      local cleaned = dequote(s)
-      local quoted = quote(cleaned)
-      table.insert(all_strings, quoted)
-      if not _available_fonts or _available_fonts[cleaned:lower()] or _generic_families[cleaned:lower()] then
-        table.insert(filtered, quoted)
-      end
+      families[#families + 1] = (dequote(s))
     end
   end
-  local result = #filtered > 0 and filtered or all_strings
+  local result = {}
+  for i, name in ipairs(resolve_font_families(families, _available_fonts)) do
+    result[i] = quote(name)
+  end
   local trailcomma = #result == 1 and ',' or ''
   return '(' .. table.concat(result, ', ') .. trailcomma .. ')'
 end
@@ -837,6 +945,7 @@ return {
   translate_border_color = translate_border_color,
   translate_font_weight = translate_font_weight,
   translate_font_family_list = translate_font_family_list,
+  resolve_font_families = resolve_font_families,
   init_available_fonts = init_available_fonts,
   consume_width = consume_width,
   consume_style = consume_style,

tests/docs/smoke-all/typst/brand-yaml/font-filtering-generics/font-filtering-generics.qmd

@@ -8,13 +8,15 @@ _quarto:
     typst:
       ensureTypstFileRegexMatches:
         -
-          # CSS generic families (sans-serif, monospace) preserved alongside real fonts
-          - 'font: \("Roboto", "sans-serif"\),'
-          - 'codefont: \("Inconsolata", "monospace"\),'
-        - []
+          - 'font: \("[^"]+"'
+          - 'codefont: \("[^"]+"'
+        -
+          - '(font|codefont): \([^)]*"(sans-serif|monospace)"'
 ---
 
-Verifies that CSS generic font family names (sans-serif, monospace, serif,
-cursive, fantasy, math) are preserved during font availability filtering,
-since they are valid fallback specifiers even though they don't appear in
-`typst fonts` output.
+Typst has no CSS generic font families, so a brand family such as
+`Roboto, sans-serif` must not pass the keyword through (Typst would warn
+`unknown font family`). Each generic is replaced by the first available font
+from a candidate list. Which font wins differs per machine, so the test only
+asserts that a concrete family is emitted and no keyword reaches the `.typ`;
+the default warning gate covers the absence of the Typst warning.

tests/docs/smoke-all/typst/brand-yaml/generic-font-families/_brand.yml

@@ -0,0 +1,7 @@
+typography:
+  base:
+    family: serif
+  headings:
+    family: sans-serif
+  monospace:
+    family: monospace

tests/docs/smoke-all/typst/brand-yaml/generic-font-families/generic-font-families.qmd

@@ -0,0 +1,28 @@
+---
+title: "Generic Font Families"
+format:
+  typst:
+    keep-typ: true
+_quarto:
+  tests:
+    typst:
+      ensureTypstFileRegexMatches:
+        -
+          - 'font: \("[^"]+"'
+          - 'codefont: \("[^"]+"'
+        -
+          - '(font|codefont): \([^)]*"(serif|sans-serif|monospace)"'
+---
+
+```{=typst}
+#set text(fallback: false)
+```
+
+The brand sets `serif`, `sans-serif` and `monospace` as the base, heading and
+code families. With `fallback: false` a missing family would show up as
+missing glyphs, so each keyword must resolve to a concrete installed font. The
+font picked differs per machine; only the absence of keywords is asserted.
+
+# Heading
+
+Body text with `inline code`.

tests/docs/smoke-all/typst/css-property-processing/system-ui-table.qmd

@@ -0,0 +1,26 @@
+---
+title: "system-ui in table styling"
+format:
+  typst:
+    keep-typ: true
+_quarto:
+  tests:
+    typst:
+      ensureTypstFileRegexMatches:
+        -
+          - '#set text\(font: \("[^"]+"'
+        -
+          - '#set text\(font: \([^)]*"(system-ui|sans-serif)"'
+---
+
+Regression test for [#11683](https://github.com/quarto-dev/quarto-cli/issues/11683):
+a `system-ui` font stack, as emitted by `gt` tables, must resolve to concrete
+families rather than reaching Typst as keywords.
+
+::: {style='font-family: system-ui, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji"'}
+
+| Col | Num |
+|-----|-----|
+| abc | 123 |
+
+:::