/* ============================================================
   ISO: An RLVR-Native Optimization Stack — project page styles
   ============================================================ */

:root {
  --ink: #1b1f24;
  --ink-2: #3f4854;
  --muted: #6b7280;
  --border: #e5e7eb;
  --surface: #ffffff;
  --bg-soft: #f7f8fa;
  --accent: #d9530b;          /* ISO orange (paper wordmark) */
  --accent-soft: #fdf1e7;
  --green: #1a7f37;           /* ISO green (method curves)  */
  --green-soft: #e9f5ec;
  --gray-mark: #5f6b7a;       /* base-model reference        */
  --link: #2563eb;
  --radius: 10px;
  --maxw: 920px;
  --maxw-wide: 1100px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: 'Noto Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--surface);
  -webkit-font-smoothing: antialiased;
}

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }
.container.wide { max-width: var(--maxw-wide); }

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3 { font-family: 'Castoro', Georgia, 'Times New Roman', serif; font-weight: 400; line-height: 1.25; }
h2 { font-size: 2rem; margin: 0 0 0.6em; }
h3 { font-size: 1.35rem; margin: 1.6em 0 0.5em; }

section { padding: 44px 0 10px; }
section + section { border-top: 1px solid var(--border); margin-top: 34px; }

.section-kicker {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 6px;
}

/* ---------- hero ---------- */
.hero { text-align: center; padding: 64px 0 18px; }
.hero .title {
  font-size: clamp(1.6rem, 3.7vw, 2.75rem);
  margin: 0 0 10px;
}
@media (min-width: 1000px) {
  .hero .title { white-space: nowrap; }
}
.hero .title .iso-mark { color: var(--accent); }
.hero .title-icon { height: 0.82em; width: auto; vertical-align: -0.08em; margin-right: 0.14em; }
.hero .subtitle {
  font-size: 1.22rem;
  color: var(--ink-2);
  font-family: 'Castoro', Georgia, serif;
  font-style: italic;
  margin: 0 0 26px;
}
.authors { font-size: 1.02rem; margin: 0 auto 8px; max-width: 860px; }
.authors a { color: var(--link); }
.authors sup { font-size: 0.7em; }
.affils { font-size: 0.92rem; color: var(--muted); max-width: 800px; margin: 0 auto 4px; }
.author-note { font-size: 0.82rem; color: var(--muted); margin-bottom: 26px; }

.hero-links { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; margin-bottom: 8px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 9px 20px;
  border-radius: 999px;
  background: #222831;
  color: #fff !important;
  font-size: 0.95rem;
  font-weight: 600;
  transition: background 0.15s ease;
}
.btn:hover { background: #000; text-decoration: none; }
.btn svg { width: 16px; height: 16px; fill: currentColor; }
.btn.btn-accent { background: var(--accent); }
.btn.btn-accent:hover { background: #b84508; }

/* ---------- teaser ---------- */
.teaser { padding-top: 26px; }
.teaser img { width: 100%; height: auto; border-radius: var(--radius); }
.figure-caption {
  font-size: 0.92rem;
  color: var(--muted);
  margin: 10px auto 0;
  max-width: 860px;
  text-align: left;
}
.figure-caption b { color: var(--ink-2); }
.teaser-fallback {
  display: none;
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 60px 24px;
  text-align: center;
  color: var(--muted);
  background: var(--bg-soft);
  font-size: 0.95rem;
}
.teaser-wrap.missing img { display: none; }
.teaser-wrap.missing .teaser-fallback { display: block; }

/* ---------- tldr / takeaway boxes ---------- */
.tldr {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
  margin: 26px 0;
}
.tldr .label {
  font-weight: 800;
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  display: block;
  margin-bottom: 6px;
}

.takeaway {
  background: var(--accent-soft);
  border: 1px solid #f3d7bd;
  border-left: 4px solid var(--accent);
  border-radius: var(--radius);
  padding: 18px 22px;
  margin: 26px 0;
  font-size: 1.02rem;
}
.takeaway .takeaway-title { font-weight: 700; color: #9a3d05; }

.principle {
  text-align: center;
  font-family: 'Castoro', Georgia, serif;
  font-size: 1.5rem;
  margin: 30px 0;
  color: var(--ink);
}
.principle .em { color: var(--accent); font-style: italic; }

/* ---------- inline math ---------- */
.math { font-family: Georgia, 'Times New Roman', serif; font-style: italic; white-space: nowrap; }
.math .rm { font-style: normal; }
.math sub, .math sup { font-size: 0.72em; }

/* ---------- alpha lab (interactive) ---------- */
.alpha-lab {
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--surface);
  box-shadow: 0 1px 3px rgba(16, 24, 40, 0.06), 0 8px 24px rgba(16, 24, 40, 0.05);
  padding: 26px 28px 20px;
  margin: 30px 0 12px;
}
.alpha-lab .lab-title {
  font-weight: 700;
  font-size: 1.05rem;
  margin-bottom: 2px;
}
.alpha-lab .lab-sub { font-size: 0.9rem; color: var(--muted); margin-bottom: 18px; }

.alpha-formula {
  text-align: center;
  font-family: Georgia, 'Times New Roman', serif;
  font-size: clamp(1.05rem, 2.6vw, 1.45rem);
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 10px;
  margin-bottom: 20px;
  overflow-x: auto;
}
.alpha-formula .coef {
  display: inline-block;
  min-width: 2.6em;
  text-align: center;
  font-weight: 700;
  font-style: normal;
  border-radius: 6px;
  padding: 0 4px;
}
.alpha-formula .coef-base { background: #eef1f4; color: var(--gray-mark); }
.alpha-formula .coef-rl { background: var(--accent-soft); color: var(--accent); }

.alpha-controls { display: flex; align-items: center; gap: 16px; margin: 6px 2px 4px; flex-wrap: wrap; }
.alpha-readout {
  font-family: Georgia, serif;
  font-size: 1.25rem;
  min-width: 5.2em;
  font-variant-numeric: tabular-nums;
}
.alpha-slider { flex: 1 1 300px; -webkit-appearance: none; appearance: none; height: 6px; border-radius: 3px;
  background: linear-gradient(90deg, #cfd6dd, #f5c9a8); outline: none; }
.alpha-slider::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 22px; height: 22px; border-radius: 50%;
  background: var(--accent); border: 3px solid #fff;
  box-shadow: 0 1px 4px rgba(0,0,0,0.35); cursor: pointer;
}
.alpha-slider::-moz-range-thumb {
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--accent); border: 3px solid #fff;
  box-shadow: 0 1px 4px rgba(0,0,0,0.35); cursor: pointer;
}
.play-btn {
  border: 1px solid var(--border); background: var(--surface); color: var(--ink-2);
  border-radius: 999px; padding: 7px 16px; font-size: 0.88rem; font-weight: 600; cursor: pointer;
}
.play-btn:hover { background: var(--bg-soft); }

.alpha-endpoints { display: flex; justify-content: space-between; font-size: 0.82rem; color: var(--muted); margin: 2px 2px 18px; }
.alpha-endpoints .rl-end { color: var(--accent); }

.alpha-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-bottom: 20px; }
.stat-tile {
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 12px 16px; background: var(--bg-soft);
}
.stat-tile.primary { background: var(--green-soft); border-color: #cfe7d6; }
.stat-tile .stat-label { font-size: 0.78rem; font-weight: 700; letter-spacing: 0.05em; text-transform: uppercase; color: var(--muted); }
.stat-tile .stat-label .no-tt { text-transform: none; }
.stat-tile.primary .stat-label { color: var(--green); }
.stat-tile .stat-value { font-size: 1.75rem; font-weight: 700; font-variant-numeric: tabular-nums; line-height: 1.2; }
.stat-tile.primary .stat-value { color: var(--green); }
.stat-tile .stat-note { font-size: 0.8rem; color: var(--muted); }

#alpha-chart { width: 100%; height: auto; display: block; }
#alpha-chart text { font-family: 'Noto Sans', sans-serif; }

.chart-legend { display: flex; gap: 22px; flex-wrap: wrap; font-size: 0.86rem; color: var(--ink-2); margin: 8px 2px 2px; }
.chart-legend .key { display: inline-flex; align-items: center; gap: 7px; }
.chart-legend .swatch-bar { width: 18px; height: 10px; border-radius: 3px; background: var(--green); display: inline-block; }
.chart-legend .swatch-dash {
  width: 3px; height: 14px; background: var(--gray-mark); display: inline-block; border-radius: 1px;
}
.chart-legend .swatch-bar.slate { background: var(--gray-mark); }
.chart-legend .swatch-dash.green { background: var(--green); }

.chart-tooltip {
  position: fixed; pointer-events: none; z-index: 50;
  background: #222831; color: #fff; font-size: 0.82rem; line-height: 1.45;
  border-radius: 8px; padding: 8px 12px; box-shadow: 0 4px 14px rgba(0,0,0,0.25);
  opacity: 0; transform: translateY(4px); transition: opacity 0.1s ease;
  max-width: 260px;
}
.chart-tooltip.show { opacity: 1; }
.chart-tooltip .tt-title { font-weight: 700; margin-bottom: 2px; }
.chart-tooltip .tt-dim { color: #aeb6bf; }

details.data-table { margin-top: 14px; font-size: 0.88rem; }
details.data-table summary { cursor: pointer; color: var(--muted); }

/* ---------- static mini bar charts (frames test / merger recovery) ---------- */
.mini-bars { margin: 22px 0; }
.mini-bar-row { display: grid; grid-template-columns: 300px 1fr 70px; align-items: center; gap: 12px; margin: 9px 0; }
.mini-bar-row .mb-label { font-size: 0.92rem; color: var(--ink-2); text-align: right; }
.mini-bar-row .mb-track { background: var(--bg-soft); border-radius: 5px; height: 16px; position: relative; overflow: hidden; }
.mini-bar-row .mb-fill { position: absolute; left: 0; top: 0; bottom: 0; border-radius: 0 4px 4px 0; background: var(--gray-mark); }
.mini-bar-row.highlight .mb-fill { background: var(--green); }
.mini-bar-row .mb-value { font-weight: 700; font-variant-numeric: tabular-nums; font-size: 0.95rem; }
.mini-bar-row.highlight .mb-value { color: var(--green); }
.mini-caption { font-size: 0.88rem; color: var(--muted); margin-top: 8px; }

.recovery-group-title { font-weight: 700; font-size: 0.95rem; margin: 18px 0 4px; color: var(--ink-2); }
.recovery .mini-bar-row { grid-template-columns: 180px 1fr 70px; }
.recovery .mb-track { height: 18px; overflow: visible; }
.recovery .mb-fill { background: var(--green); border-radius: 0 4px 4px 0; }
.recovery .ref-100 { position: absolute; top: -3px; bottom: -3px; width: 2px; background: var(--ink-2); opacity: 0.55; z-index: 1; }

/* ---------- iso principle animation (U rotates, Sigma frozen, V rotates) ---------- */
.iso-anim {
  display: flex; align-items: center; justify-content: center;
  gap: 4px; flex-wrap: wrap;
  margin: 6px 0 34px;
}
.iso-anim-item { text-align: center; }
.iso-anim-item canvas { display: block; margin: 0 auto 2px; }
.iso-anim-op { font-size: 1.6rem; color: var(--muted); padding: 0 6px 34px; }
.iso-anim-label { font-size: 0.86rem; color: var(--muted); }
.iso-anim-label b { color: var(--ink-2); }
.iso-anim-item:first-child .iso-anim-label b,
.iso-anim-item:last-child .iso-anim-label b { color: var(--accent); }

.sigma-matrix { display: flex; align-items: stretch; justify-content: center; margin-bottom: 10px; height: 130px; }
.sigma-matrix .bracket { width: 12px; border: 2.5px solid var(--ink-2); }
.sigma-matrix .bracket.left  { border-right: none; border-radius: 4px 0 0 4px; }
.sigma-matrix .bracket.right { border-left: none;  border-radius: 0 4px 4px 0; }
.sigma-grid {
  display: grid; grid-template-columns: repeat(4, 30px); grid-template-rows: repeat(4, 30px);
  align-items: center; justify-items: center; padding: 2px 6px; align-self: center;
  font-size: 1.02rem; color: var(--ink-2);
}
.sigma-grid .s1 { grid-area: 1 / 1; }
.sigma-grid .s2 { grid-area: 2 / 2; }
.sigma-grid .s3 { grid-area: 3 / 3; }
.sigma-grid .s4 { grid-area: 4 / 4; }

/* ---------- method cards ---------- */
.card-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin: 26px 0; }
.method-card {
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 22px; background: var(--bg-soft);
}
.method-card .card-tag {
  display: inline-block; font-size: 0.72rem; font-weight: 800; letter-spacing: 0.1em;
  text-transform: uppercase; color: #fff; background: var(--accent);
  border-radius: 999px; padding: 3px 10px; margin-bottom: 10px;
}
.method-card.online .card-tag { background: var(--green); }
.method-card h4 { margin: 0 0 8px; font-size: 1.12rem; }
.method-card p { margin: 0; font-size: 0.94rem; color: var(--ink-2); }
.method-card .card-claim {
  margin-top: 14px;
  padding: 10px 14px;
  background: var(--accent-soft);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  font-weight: 700;
  font-size: 0.93rem;
  color: #9a3d05;
}
.method-card.online .card-claim {
  background: var(--green-soft);
  border-left-color: var(--green);
  color: var(--green);
}

/* ---------- figures ---------- */
.figure { margin: 30px 0; text-align: center; }
.figure img { max-width: 100%; height: auto; border-radius: 8px; }
.figure.bordered img { border: 1px solid var(--border); padding: 8px; background: #fff; }
.fig-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; margin: 26px 0; }
.fig-grid .figure { margin: 0; }
.fig-grid .figure-caption { text-align: center; }

/* ---------- tables ---------- */
.table-scroll { overflow-x: auto; margin: 22px 0 6px; border: 1px solid var(--border); border-radius: var(--radius); }
table.results {
  border-collapse: collapse; width: 100%; font-size: 0.83rem;
  font-variant-numeric: tabular-nums; white-space: nowrap;
}
table.results th, table.results td { padding: 7px 12px; text-align: center; border-bottom: 1px solid var(--border); }
table.results th { background: var(--bg-soft); font-weight: 700; color: var(--ink-2); }
table.results td:first-child, table.results th:first-child { text-align: left; position: sticky; left: 0; background: inherit; }
table.results th:first-child { background: var(--bg-soft); }
table.results tbody tr { background: #fff; }
table.results tbody tr:last-child td { border-bottom: none; }
table.results tr.expert td { background: #f0f4fa; }
table.results tr.ours td { background: var(--green-soft); font-weight: 600; }
table.results td.best { font-weight: 800; }
table.results .subhead td { background: var(--bg-soft); font-weight: 700; text-align: left; color: var(--ink-2); }
.table-note { font-size: 0.84rem; color: var(--muted); margin: 6px 2px 24px; }

/* ---------- citation ---------- */
.bibtex-wrap { position: relative; margin: 22px 0; }
pre.bibtex {
  background: #22272e; color: #d5dbe1; font-size: 0.83rem; line-height: 1.55;
  border-radius: var(--radius); padding: 20px 22px; overflow-x: auto; margin: 0;
}
.copy-btn {
  position: absolute; top: 10px; right: 10px;
  background: rgba(255,255,255,0.12); color: #fff; border: none; border-radius: 6px;
  font-size: 0.78rem; padding: 6px 12px; cursor: pointer;
}
.copy-btn:hover { background: rgba(255,255,255,0.22); }

/* ---------- footer ---------- */
footer {
  border-top: 1px solid var(--border);
  margin-top: 60px; padding: 30px 0 44px;
  font-size: 0.86rem; color: var(--muted); text-align: center;
}

/* ---------- responsive ---------- */
@media (max-width: 760px) {
  .card-grid, .fig-grid { grid-template-columns: 1fr; }
  .alpha-stats { grid-template-columns: 1fr; }
  .mini-bar-row { grid-template-columns: 1fr; gap: 4px; }
  .mini-bar-row .mb-label { text-align: left; }
  .recovery .mini-bar-row { grid-template-columns: 120px 1fr 60px; }
  body { font-size: 16px; }
}