/* OpenAI Math manuscript index */

:root {
  --bg: #fbfaf7;
  --surface: #ffffff;
  --surface-2: #f3f1ec;
  --ink: #1d1c1a;
  --ink-2: #4a4843;
  --ink-3: #7a776f;
  --line: #e4e0d7;
  --line-2: #d3cec2;
  --accent: #275b59;
  --accent-ink: #ffffff;
  --focus: #2f7d79;
  --lean: #3d6b2f;
  --lean-bg: #e6f0df;
  --trace: #6a4a8c;
  --trace-bg: #efe8f6;
  --shadow: 0 1px 2px rgb(40 30 10 / .05), 0 2px 8px rgb(40 30 10 / .04);
  --l-tint: 96%;
  --l-mark: 52%;
  --c-tint: .025;
  --c-mark: .12;
  --serif: "Source Serif 4", "Iowan Old Style", Georgia, serif;
  --sans: Inter, system-ui, -apple-system, "Segoe UI", sans-serif;
  --radius: 10px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #151514;
    --surface: #1d1d1b;
    --surface-2: #262523;
    --ink: #ece9e2;
    --ink-2: #c3bfb5;
    --ink-3: #908c83;
    --line: #2f2e2b;
    --line-2: #3f3d39;
    --accent: #7cc4bf;
    --accent-ink: #0f1f1e;
    --focus: #7cc4bf;
    --lean: #a7d48f;
    --lean-bg: #24331d;
    --trace: #c9a9ec;
    --trace-bg: #2e2539;
    --shadow: none;
    --l-tint: 24%;
    --l-mark: 72%;
    --c-tint: .03;
    --c-mark: .11;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #151514; --surface: #1d1d1b; --surface-2: #262523;
  --ink: #ece9e2; --ink-2: #c3bfb5; --ink-3: #908c83;
  --line: #2f2e2b; --line-2: #3f3d39;
  --accent: #7cc4bf; --accent-ink: #0f1f1e; --focus: #7cc4bf;
  --lean: #a7d48f; --lean-bg: #24331d; --trace: #c9a9ec; --trace-bg: #2e2539;
  --shadow: none; --l-tint: 24%; --l-mark: 72%; --c-tint: .03; --c-mark: .11;
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-padding-top: 72px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 15px/1.55 var(--sans);
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; border-radius: 4px; }
[hidden] { display: none !important; }

/* Per-subject colour from a single hue */
[style*="--hue"] {
  --tint: oklch(var(--l-tint) var(--c-tint) var(--hue));
  --mark: oklch(var(--l-mark) var(--c-mark) var(--hue));
}

/* ---------- Top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 12px clamp(16px, 4vw, 40px);
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--line);
}
.brand { color: var(--ink); text-decoration: none; font-weight: 600; letter-spacing: -.01em; white-space: nowrap; }
.brand-mark { font-family: var(--serif); color: var(--accent); font-size: 1.25em; margin-right: 2px; }
.brand-sub { color: var(--ink-3); font-weight: 400; margin-left: 4px; }
.topnav { display: flex; gap: 20px; }
.topnav a { color: var(--ink-2); text-decoration: none; font-size: 14px; }
.topnav a:hover { color: var(--ink); }
@media (max-width: 560px) { .brand-sub { display: none; } }

/* ---------- Home ---------- */
.home { max-width: 1180px; margin: 0 auto; padding: 0 clamp(16px, 4vw, 40px); }
.hero { padding: clamp(40px, 8vw, 88px) 0 32px; max-width: 820px; }
.hero h1 {
  font: 600 clamp(30px, 5vw, 48px)/1.08 var(--serif);
  letter-spacing: -.02em; margin: 0 0 16px; text-wrap: balance;
}
.lede { color: var(--ink-2); font-size: 17px; margin: 0 0 24px; max-width: 64ch; }
.hero-search {
  display: flex; align-items: center; gap: 8px;
  background: var(--surface); border: 1px solid var(--line-2); border-radius: 999px;
  padding: 6px 6px 6px 18px; box-shadow: var(--shadow);
}
.hero-search:focus-within { border-color: var(--focus); }
.hero-search svg, .search svg { width: 18px; height: 18px; flex: none; fill: none; stroke: var(--ink-3); stroke-width: 2; stroke-linecap: round; }
.hero-search input { flex: 1; min-width: 0; border: 0; background: none; font: inherit; font-size: 16px; color: var(--ink); padding: 8px 0; outline: none; }
.hero-search button {
  border: 0; border-radius: 999px; background: var(--accent); color: var(--accent-ink);
  font: 500 14px var(--sans); padding: 10px 18px; cursor: pointer;
}
.stats { display: flex; flex-wrap: wrap; gap: 12px 36px; margin: 28px 0 0; }
.stats div { display: flex; flex-direction: column-reverse; }
.stats dt { color: var(--ink-3); font-size: 12px; text-transform: uppercase; letter-spacing: .06em; }
.stats dd { margin: 0; font: 600 24px/1.2 var(--serif); font-variant-numeric: tabular-nums; }

.section-h {
  font: 600 13px var(--sans); text-transform: uppercase; letter-spacing: .08em;
  color: var(--ink-3); margin: 40px 0 16px;
}
.tiles { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 14px; }
.tile {
  position: relative; display: flex; flex-direction: column; gap: 6px;
  padding: 18px 18px 16px 20px; border-radius: var(--radius);
  background: var(--surface); border: 1px solid var(--line);
  color: var(--ink); text-decoration: none; box-shadow: var(--shadow);
  transition: transform .15s ease, border-color .15s ease, background .15s ease;
  overflow: hidden;
}
.tile::before { content: ""; position: absolute; inset: 0 auto 0 0; width: 4px; background: var(--mark); }
.tile:hover { transform: translateY(-2px); border-color: var(--mark); background: var(--tint); }
.tile h3 { font: 600 19px/1.25 var(--serif); margin: 0; letter-spacing: -.01em; }
.tile p { margin: 0; color: var(--ink-2); font-size: 13.5px; line-height: 1.45; flex: 1; }
.tile-stats { display: flex; gap: 14px; margin-top: 8px; color: var(--ink-3); font-size: 12.5px; }
.tile-stats b { color: var(--ink); font-weight: 600; font-variant-numeric: tabular-nums; }
.recent .papers { display: grid; grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); gap: 14px; }
@media (max-width: 420px) { .recent .papers { grid-template-columns: 1fr; } }
.see-all { margin: 20px 0 0; font-weight: 500; }

/* ---------- Subject layout ---------- */
.layout {
  display: grid; grid-template-columns: 270px minmax(0, 1fr); gap: 48px;
  max-width: 1240px; margin: 0 auto; padding: 0 clamp(16px, 4vw, 40px);
}
.sidebar {
  position: sticky; top: 61px; align-self: start;
  max-height: calc(100vh - 61px); overflow-y: auto;
  padding: 28px 4px 40px 0; font-size: 13.5px;
  scrollbar-width: thin;
}
.sidebar h2 {
  font: 600 11.5px var(--sans); text-transform: uppercase; letter-spacing: .08em;
  color: var(--ink-3); margin: 0 0 8px;
}
.subjects-nav ul, .toc ol { list-style: none; margin: 0; padding: 0; }
.subjects-nav a {
  display: flex; align-items: center; gap: 9px; padding: 5px 8px; border-radius: 6px;
  color: var(--ink-2); text-decoration: none;
}
.subjects-nav a:hover { background: var(--surface-2); color: var(--ink); }
.subjects-nav a[aria-current] { background: var(--tint); color: var(--ink); font-weight: 600; }
.subjects-nav .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--mark); flex: none; }
.subjects-nav .n, .group-h .n { margin-left: auto; color: var(--ink-3); font-size: 12px; font-variant-numeric: tabular-nums; font-weight: 400; }
.toc { margin-top: 28px; }
.toc a {
  display: flex; gap: 10px; padding: 4px 8px; border-radius: 6px;
  color: var(--ink-2); text-decoration: none; line-height: 1.35;
}
.toc a:hover { background: var(--surface-2); color: var(--ink); }
.toc a.active { color: var(--ink); background: var(--tint); }
.toc-num { color: var(--ink-3); font-variant-numeric: tabular-nums; font-size: 12px; padding-top: 1px; flex: none; }
.toc li.dim { opacity: .35; }

.content { min-width: 0; padding: 28px 0 64px; max-width: 860px; }
.content.wide { max-width: 1000px; margin: 0 auto; padding-left: clamp(16px, 4vw, 40px); padding-right: clamp(16px, 4vw, 40px); }
.crumbs { margin: 0 0 4px; font-size: 13px; color: var(--ink-3); }
.crumbs a { color: var(--ink-3); }
.subject-head h1 {
  font: 600 clamp(28px, 4.5vw, 40px)/1.1 var(--serif); letter-spacing: -.02em; margin: 0 0 8px;
}
.subject-head h1::after {
  content: ""; display: block; width: 48px; height: 4px; border-radius: 2px;
  margin-top: 14px; background: var(--mark, var(--accent));
}
.subject-head .lede { font-size: 15.5px; margin-bottom: 20px; }

@media (max-width: 900px) {
  .layout { grid-template-columns: minmax(0, 1fr); gap: 0; }
  .sidebar { min-width: 0; position: static; max-height: none; padding: 16px 0 0; overflow: visible; }
  .subjects-nav ul { display: flex; gap: 6px; overflow-x: auto; padding-bottom: 6px; scrollbar-width: none; }
  .subjects-nav li { flex: none; }
  .subjects-nav a { border: 1px solid var(--line); white-space: nowrap; padding: 4px 10px; }
  .subjects-nav .n { display: none; }
  .subjects-nav h2, .toc { display: none; }
}

/* ---------- Controls ---------- */
.controls {
  position: sticky; top: 53px; z-index: 5;
  background: var(--bg); padding: 10px 0 12px; margin-bottom: 8px;
  border-bottom: 1px solid var(--line);
}
.search {
  display: flex; align-items: center; gap: 10px;
  background: var(--surface); border: 1px solid var(--line-2); border-radius: 8px; padding: 0 10px 0 12px;
}
.search:focus-within { border-color: var(--focus); box-shadow: 0 0 0 3px color-mix(in srgb, var(--focus) 18%, transparent); }
.search input {
  flex: 1; min-width: 0; border: 0; background: none; outline: none;
  font: inherit; font-size: 15px; color: var(--ink); padding: 10px 0;
}
.search kbd {
  font: 500 11px var(--sans); color: var(--ink-3); border: 1px solid var(--line-2);
  border-radius: 4px; padding: 1px 6px;
}
@media (hover: none) { .search kbd { display: none; } }
.control-row { display: flex; flex-wrap: wrap; align-items: center; gap: 10px 18px; margin-top: 10px; font-size: 13.5px; color: var(--ink-2); }
.seg { display: inline-flex; border: 1px solid var(--line-2); border-radius: 7px; overflow: hidden; }
.seg button {
  border: 0; background: var(--surface); color: var(--ink-2); font: inherit; padding: 5px 11px; cursor: pointer;
}
.seg button + button { border-left: 1px solid var(--line-2); }
.seg button[aria-pressed="true"] { background: var(--ink); color: var(--bg); }
.chk { display: inline-flex; align-items: center; gap: 6px; cursor: pointer; }
.chk input { accent-color: var(--accent); margin: 0; }
.sel select {
  margin-left: 6px; font: inherit; color: var(--ink); background: var(--surface);
  border: 1px solid var(--line-2); border-radius: 6px; padding: 4px 6px;
}
.status { margin-left: auto; color: var(--ink-3); font-variant-numeric: tabular-nums; }

.chips { display: flex; flex-wrap: wrap; gap: 6px; margin: 4px 0 8px; }
.chip {
  font: 500 12.5px var(--sans); color: var(--ink-2); background: var(--surface);
  border: 1px solid var(--line-2); border-radius: 999px; padding: 4px 11px 4px 9px; cursor: pointer;
  display: inline-flex; align-items: center; gap: 6px;
}
.chip::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--mark); }
.chip:hover { border-color: var(--mark); }
.chip[aria-pressed="true"] { background: var(--tint); border-color: var(--mark); color: var(--ink); }

/* ---------- Families & papers ---------- */
.family { padding: 28px 0 8px; border-bottom: 1px solid var(--line); }
.family:last-child { border-bottom: 0; }
.family-num { font: 600 12px var(--sans); color: var(--mark, var(--ink-3)); letter-spacing: .06em; text-transform: uppercase; }
.family-title { font: 600 23px/1.25 var(--serif); letter-spacing: -.01em; margin: 4px 0 8px; text-wrap: balance; }
.family-desc { margin: 0 0 10px; color: var(--ink-2); font-family: var(--serif); font-size: 16.5px; line-height: 1.55; max-width: 70ch; }
.family-links { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; margin-bottom: 14px; }
.count { color: var(--ink-3); font-size: 12.5px; margin-right: 4px; }
.papers { display: flex; flex-direction: column; gap: 10px; }
.view-family .papers { padding-left: 14px; border-left: 2px solid var(--tint, var(--line)); }
.view-flat .family-head, .view-flat .family { border: 0; padding: 0; }
.view-flat .family-head { display: none; }
.view-flat .papers { padding: 0; border: 0; }

.subject-group { padding: 20px 0 8px; }
.group-h { display: flex; align-items: baseline; gap: 10px; font: 600 21px/1.3 var(--serif); margin: 0 0 12px; }
.group-h::before { content: ""; width: 10px; height: 10px; border-radius: 50%; background: var(--mark); align-self: center; }
.group-h a { color: var(--ink); text-decoration: none; }
.group-h a:hover { text-decoration: underline; }

.paper {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 16px 18px 12px; box-shadow: var(--shadow);
  transition: border-color .15s ease;
}
.paper:hover { border-color: var(--line-2); }
.paper-title { font: 600 17.5px/1.35 var(--serif); margin: 0 0 6px; letter-spacing: -.005em; }
.paper-title a { color: var(--ink); text-decoration: none; }
.paper-title a:hover { color: var(--accent); text-decoration: underline; }
.meta { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 8px; font-size: 12.5px; color: var(--ink-3); margin-bottom: 8px; }
.meta time { font-variant-numeric: tabular-nums; margin-right: 2px; }
.badge {
  display: inline-flex; align-items: center; font: 500 11.5px/1 var(--sans);
  padding: 4px 8px; border-radius: 999px; text-decoration: none;
  background: var(--surface-2); color: var(--ink-2); border: 1px solid transparent; white-space: nowrap;
}
a.badge:hover { border-color: var(--line-2); }
.badge.subj { background: var(--tint); color: var(--ink); }
.badge.subj::before { content: ""; width: 6px; height: 6px; border-radius: 50%; background: var(--mark); margin-right: 6px; }
.badge.lean { background: var(--lean-bg); color: var(--lean); }
.badge.trace { background: var(--trace-bg); color: var(--trace); }

.abstract {
  font-family: var(--serif); font-size: 15.5px; line-height: 1.58; color: var(--ink-2);
  display: -webkit-box; -webkit-box-orient: vertical; -webkit-line-clamp: 3; line-clamp: 3; overflow: hidden;
}
.paper.open .abstract { display: block; -webkit-line-clamp: unset; }
.abstract a { color: var(--accent); }
.actions { display: flex; flex-wrap: wrap; align-items: center; gap: 4px; margin-top: 10px; }
.act {
  font: 500 12.5px var(--sans); color: var(--ink-2); background: none; border: 1px solid var(--line);
  border-radius: 6px; padding: 4px 10px; text-decoration: none; cursor: pointer;
}
.act:hover { background: var(--surface-2); color: var(--ink); }
.act.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.act.primary:hover { filter: brightness(1.08); background: var(--accent); color: var(--accent-ink); }
.act.more { margin-left: auto; border-color: transparent; color: var(--ink-3); }
.act.more:hover { color: var(--ink); }
.act.done { border-color: var(--lean); color: var(--lean); }

.empty { color: var(--ink-3); padding: 40px 0; text-align: center; }
.linkish { background: none; border: 0; font: inherit; color: var(--accent); text-decoration: underline; cursor: pointer; padding: 0; }

.katex { font-size: 1.04em; }
.paper-title .katex, .family-title .katex { font-size: 1em; }

/* ---------- Footer ---------- */
.foot {
  border-top: 1px solid var(--line); margin-top: 48px;
  padding: 24px clamp(16px, 4vw, 40px) 40px; color: var(--ink-3); font-size: 13px;
}
.foot p { max-width: 1180px; margin: 0 auto; }
.foot a { color: var(--ink-2); }

@media (max-width: 560px) {
  body { font-size: 14.5px; }
  .paper { padding: 14px 14px 10px; }
  .view-family .papers { padding-left: 0; border-left: 0; }
  .status { width: 100%; margin-left: 0; }
  .controls { top: 49px; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }