The new theme CSS files introduced several patterns that cause
scroll jank and memory pressure, especially on mobile:

- terminal.css: Full-viewport fixed pseudo-element with repeating
  gradient scanlines forced GPU compositing on every scroll frame.
  Now limited to desktop only with will-change layer promotion.
- codex.css/sakura.css: text-rendering: optimizeLegibility on body
  triggered expensive kerning/ligature computation on all text.
- codex.css: font-feature-settings forced text shaper on every glyph.
- codex.css: hyphens: auto required dictionary lookups during layout.
- style.css: transition: all on buttons and sidebar links caused
  unnecessary animation work during scroll hover state changes.
- main.ts: checkReadItems did O(n) individual querySelector calls
  per scroll tick; switched to single querySelectorAll batch query.
- Polling interval reduced from 1s to 3s (scroll handler already
  covers the normal case, polling is just a robustness fallback).

https://claude.ai/code/session_0187FXrbScDSWfbNEk9SfJaj

Refined: softer dark-mode link color (#a0c4e8), fix export button
vertical alignment with inline-flex, tighten settings page spacing
(reduce gaps from 3rem to 1.5rem).

Terminal: switch accent from cyan to green (#4ae54a dark / #1a7a2e
light), add proper light mode with pale steel background, scanlines
only in dark mode.

Sidebar: add quick-access controls in footer — moon/sun icon toggles
light/dark, circle icon cycles through style themes showing current
name. Both update reactively on state change.

Add THEMES.md with full documentation on creating new themes:
variable reference, selector guide, light/dark mode tips, and the
registration process.

https://claude.ai/code/session_01Jv3c8GdaDQMm5WYwHUJMVe

Adds a style theme system that layers additional CSS files on top of the
base stylesheet. Themes are loaded/unloaded dynamically via <link> tags.

- Default: existing look, unchanged
- Refined: typographic rhythm fixes, consistent spacing on settings page
- Terminal: monospace, dark phosphor CRT aesthetic (scanlines, cyan glow)
- Codex: book/Tufte-inspired with warm paper tones, serif type, fleurons
- Sakura: Japanese-inspired calm aesthetic (named for neko = cat)

Each theme supports both light and dark mode. Style selection persists
in localStorage and is independent of the light/dark toggle.

https://claude.ai/code/session_01Jv3c8GdaDQMm5WYwHUJMVe