fix: follow UDT's font size and live theme changes

UDT gives font sizes to keystone's fonts page, which writes
~/.config/keystone/fonts.json. deck-it hardcoded px sizes, so changing
the size on the fonts page did nothing on the tablet. theme.css now
carries --udt-font-size (override.deckit, else base, 8 to 40px, as
quickshell checks) on html, and deck.css sizes text in rem, scaled from
the old 14px design.

The page loaded theme.css once, so a scheme, wallpaper or size change
reached the tablet only after a reload. The shell now re-reads it every
5s and on visibility, swapping it into a <style> only when it changed,
and sets meta theme-color from --udt-base instead of Macchiato's
hardcoded base.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 24 insertions, 2 deletions

diff --git a/deckit/theme.py b/deckit/theme.py
index 2ed3d51..142a79f 100644
--- a/deckit/theme.py
+++ b/deckit/theme.py
@@ -21,6 +21,7 @@ wallpaper accent to ~/.cache/udt/udt-accent.rasi. deck-it reads both rather
 than restating the colours, so a scheme or wallpaper change reaches the tablet.
 """
 
+import json
 import re
 from pathlib import Path
 
@@ -31,6 +32,9 @@ BORDER = re.compile(r"rgb\(\s*([0-9a-fA-F]{6})\s*\)")
 PALETTE_PATH = Path.home() / ".config" / "rofi" / "udt" / "palette.rasi"
 ACCENT_PATH = Path.home() / ".cache" / "udt" / "udt-accent.rasi"
 BORDER_PATH = Path.home() / ".cache" / "udt" / "udt-border.lua"
+# Keystone's fonts page owns text sizes: deck-it's own override, else the base.
+FONTS_PATH = Path.home() / ".config" / "keystone" / "fonts.json"
+FONT_SIZE = 14  # px, the size deck.css was designed at
 
 # Catppuccin Macchiato, used before UDT has ever generated its files.
 FALLBACK = {
@@ -58,8 +62,22 @@ def parse_border(text: str) -> list[str]:
     return ["#" + value.lower() for value in BORDER.findall(text)]
 
 
-def css(colors: dict, accent: str | None, border: list[str] | None = None) -> str:
+def parse_font_size(text: str) -> int | None:
+    """deck-it's px size from keystone's fonts.json, range-checked as quickshell does."""
+    try:
+        data = json.loads(text)
+        px = (data.get("override") or {}).get("deckit", data.get("base"))
+    except (ValueError, AttributeError):
+        return None
+    if isinstance(px, (int, float)) and not isinstance(px, bool) and 8 <= px <= 40:
+        return round(px)
+    return None
+
+
+def css(colors: dict, accent: str | None, border: list[str] | None = None,
+        font_size: int | None = None) -> str:
     lines = [":root {"]
+    lines.append(f"  --udt-font-size: {font_size or FONT_SIZE}px;")
     lines += [f"  --udt-{name}: {value};" for name, value in colors.items()]
     lines.append(f"  --udt-accent: {accent or FALLBACK['accent']};")
     stops = border if border and len(border) >= 3 else [
@@ -86,4 +104,8 @@ def load() -> str:
         border = parse_border(BORDER_PATH.read_text())
     except OSError:
         border = None
-    return css(colors, accent, border)
+    try:
+        font_size = parse_font_size(FONTS_PATH.read_text())
+    except OSError:
+        font_size = None
+    return css(colors, accent, border, font_size)