Catppuccin, Gruvbox, Solarized and High contrast themes

Each in light and dark. The published palettes missed AA in 19 places,
mostly Solarized and Catppuccin Latte, so each failing colour is moved
the least distance, toward black or white, that clears every pair it is
drawn in. Solarized dark's base0 had to rise to base1 to read on base02,
so its dim sits between base2 and base1 to keep three steps of type.

tests/contrast.js checks every palette against the pairs the page draws,
and a border that matches the ground it sits on. Its first run caught
Classic's links at 3.7:1 on the source list and Modern's faint at 4.3:1
on inputs; both are tuned. A failed toast moves to --panel, since the
error colours are tuned for the page's grounds, not --raise.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/contrast.js

@@ -0,0 +1,62 @@
+// Every theme's palette, checked against WCAG AA for the pairs the page actually draws. The
+// published palettes ipx borrows (Flat Remix, Paper, Adwaita...) fell short in places: an unread
+// count at 2.6:1, tags at 3.2:1. Each was tuned by hand; this keeps a new or edited theme honest.
+//
+//   node tests/contrast.js
+const fs = require('fs');
+const path = require('path');
+
+const css = fs.readFileSync(path.join(__dirname, '../web/app.css'), 'utf8');
+const blocks = {};
+for (const m of css.matchAll(/^(:root(?:\[[^\]]+\])*)\s*\{([^}]*)\}/gm)) {
+  const vars = {};
+  for (const v of m[2].matchAll(/--(\w+):\s*(#[0-9a-f]{6})\b/gi)) vars[v[1]] = v[2].toLowerCase();
+  if (Object.keys(vars).length) blocks[m[1]] = vars;
+}
+
+const lum = h => {
+  const c = [1, 3, 5].map(i => parseInt(h.slice(i, i + 2), 16) / 255)
+    .map(c => c <= .03928 ? c / 12.92 : ((c + .055) / 1.055) ** 2.4);
+  return .2126 * c[0] + .7152 * c[1] + .0722 * c[2];
+};
+const ratio = (a, b) => { const x = lum(a), y = lum(b); return (Math.max(x, y) + .05) / (Math.min(x, y) + .05); };
+
+// [colour, grounds it is drawn on, minimum]. 4.5 for text, 3 for an icon, dot or bar.
+const RULES = [
+  ['fg', ['bg', 'panel', 'panel2', 'raise'], 4.5],
+  ['dim', ['bg', 'panel', 'panel2'], 4.5],       // metadata, labels
+  ['faint', ['bg', 'panel', 'panel2'], 4.5],     // hints, column headings, the status bar
+  ['accent', ['bg', 'panel'], 4.5],              // links, in the list and the reader
+  ['ink', ['accent'], 4.5],                      // a primary button's label
+  ['ink', ['accent2'], 4.5],                     // the unread count on its badge
+  ['accent2', ['bg', 'panel', 'raise'], 3],      // the unread dot, the EQ bars, download bars
+  ['bad', ['bg', 'panel'], 4.5],                 // error text, the Error tag, a failed toast
+  ['warn', ['bg', 'panel'], 4.5],                // the Gone tag, log warnings
+  ['good', ['bg', 'panel', 'panel2'], 3],        // the downloaded and subscribed icons
+];
+
+const base = blocks[':root'];
+const themes = {};
+for (const sel of Object.keys(blocks)) {
+  const t = sel.match(/data-theme="(\w+)"/);
+  if (!t) continue;
+  const light = /data-mode="light"/.test(sel);
+  // A theme's dark half is :root under its own block; its light half adds the light block.
+  const name = `${t[1]}${light ? ' light' : ''}`;
+  themes[name] = light
+    ? { ...base, ...blocks[`:root[data-theme="${t[1]}"]`], ...blocks[sel] }
+    : { ...base, ...blocks[sel] };
+}
+themes['modern'] = base;
+
+let bad = 0;
+for (const [name, p] of Object.entries(themes)) {
+  for (const [fg, grounds, min] of RULES) for (const g of grounds) {
+    const r = ratio(p[fg], p[g]);
+    if (r < min) { bad++; console.log(`FAIL ${name}: --${fg} on --${g} is ${r.toFixed(2)}:1, needs ${min}`); }
+  }
+  // A border the same colour as the ground it is drawn on does not show (Nordic, once).
+  if (p.line === p.panel2) { bad++; console.log(`FAIL ${name}: --line is --panel2, so borders on it vanish`); }
+}
+if (bad) process.exit(1);
+console.log(`OK: ${Object.keys(themes).length} palettes clear AA for every pair the page draws`);