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, 10 insertions, 0 deletions

diff --git a/tests/test_theme.py b/tests/test_theme.py
index c1fe1de..f14b0f1 100644
--- a/tests/test_theme.py
+++ b/tests/test_theme.py
@@ -55,6 +55,16 @@ class Theme(unittest.TestCase):
         for index, value in enumerate(["#111111", "#222222", "#333333"], 1):
             self.assertIn(f"--udt-border-{index}: {value}", out)
 
+    def test_font_size_prefers_override_then_base(self):
+        self.assertEqual(theme.parse_font_size('{"base": 16, "override": {"deckit": 18.6}}'), 19)
+        self.assertEqual(theme.parse_font_size('{"base": 16, "override": {"rofi": 14}}'), 16)
+        for bad in ('{"base": 99}', '{"base": "16"}', "not json", "[]"):
+            self.assertIsNone(theme.parse_font_size(bad))
+
+    def test_css_exposes_font_size(self):
+        self.assertIn("--udt-font-size: 17px", theme.css({}, None, font_size=17))
+        self.assertIn(f"--udt-font-size: {theme.FONT_SIZE}px", theme.css({}, None))
+
     def test_load_falls_back_when_files_are_missing(self):
         saved = (theme.PALETTE_PATH, theme.ACCENT_PATH)
         theme.PALETTE_PATH = Path("/nonexistent/palette.rasi")