How can I create a document that adheres to the OS font?

With CSS3, I am able to specify system-ui, where required. However, all browser stylesheets default to that, regardless. Typst appears to provide no equivalent.

Worse, typst fonts fails to enumerate all FontConfig aliases:

  1. import subprocess
    import xml.etree.ElementTree as ET
    from pathlib import Path
    
    
    def resolve_fontconfig_files(seed: Path, visited: set[Path] | None = None) -> list[Path]:
        """Recursively resolve all FontConfig config files via <include> directives."""
        if visited is None:
            visited = set()
    
        seed = seed.resolve()
        if not seed.exists() or seed in visited:
            return []
        visited.add(seed)
    
        files: list[Path] = [seed]
    
        try:
            tree = ET.parse(seed)
        except ET.ParseError:
            return files
    
        for include in tree.getroot().iter("include"):
            text = (include.text or "").strip()
            if not text:
                continue
            target = (seed.parent / text).resolve()
            if target.is_dir():
                for child in sorted(target.glob("*.conf")):
                    files.extend(resolve_fontconfig_files(child, visited))
            else:
                files.extend(resolve_fontconfig_files(target, visited))
    
        return files
    
    
    def collect_alias_names() -> list[str]:
        """Extract declared alias names from FontConfig XML config files."""
        roots: list[Path] = [
            Path("/etc/fonts/fonts.conf"),
            Path.home() / ".config/fontconfig/fonts.conf",
            Path.home() / ".fonts.conf",
        ]
    
        names: list[str] = []
        seen: set[str] = set()
        visited: set[Path] = set()
    
        for root in roots:
            for path in resolve_fontconfig_files(root, visited):
                try:
                    tree = ET.parse(path)
                except ET.ParseError:
                    continue
                for alias_el in tree.getroot().iter("alias"):
                    family_el = alias_el.find("family")
                    if family_el is None or not (family_el.text or "").strip():
                        continue
    
                    # Skip reverse mappings (real font → generic); they only have
                    # <accept> or <default>, never <prefer>.
                    if alias_el.find("prefer") is None:
                        continue
    
                    name = family_el.text.strip()
                    if name not in seen:
                        seen.add(name)
                        names.append(name)
    
        return names
    
    
    def resolve_alias(alias: str) -> list[str]:
        """Use fc-match to resolve an alias to its ordered list of families."""
        result = subprocess.run(
            ["fc-match", "--sort", "--format=%{family}\\n", alias],
            capture_output=True,
            text=True,
        )
        families: list[str] = []
        seen: set[str] = set()
        for line in result.stdout.splitlines():
            name = line.strip()
            if name and name not in seen:
                seen.add(name)
                families.append(name)
        return families
    
    
    def enumerate_fontconfig_aliases() -> dict[str, list[str]]:
        """Return a mapping of alias name → resolved font families via fc-match."""
        return {alias: resolve_alias(alias) for alias in collect_alias_names()}
    
    
    if __name__ == "__main__":
        import pprint
        pprint.pprint(collect_alias_names())
    
  2. ['system-ui',
     'sans-serif',
     'monospace',
     'FontAwesome',
     'emoji',
     'math',
     'serif',
     'fantasy',
     'cursive']
    

Consequently, I can’t even revert to kcm_fonts’s typeface:

  1. #!/usr/bin/env bash
    grep -i font $HOME/.config/kdeglobals | jc --ini | jq | yq -P
    
  2. font: Monospace,10,-1,5,400,0,0,0,0,0,0,0,0,0,0,1
    menuFont: Monospace,10,-1,5,400,0,0,0,0,0,0,0,0,0,0,1
    smallestReadableFont: Monospace,10,-1,5,400,0,0,0,0,0,0,0,0,0,0,1
    toolBarFont: Monospace,10,-1,5,400,0,0,0,0,0,0,0,0,0,0,1
    activeFont: Monospace,10,-1,5,400,0,0,0,0,0,0,0,0,0,0,1
    

I don’t understand how one is supposed to create accessible markup, if the document cannot dynamically adhere to the DE’s typeface, and the size thereof.

Context

My sole interest in Typst is that it resolves what github.com/whatwg/html/issues/8751#issuecomment-2676253060 describes.