/* ═══════════════════════════════════════════════════════════════
   Academic Project Page — Style Sheet
   ═══════════════════════════════════════════════════════════════ */

/* ── CSS Custom Properties (easy theming) ──────────────────── */
:root {
  /* Colors — monochrome palette */
  --primary:      #222;
  --primary-dark: #000;
  --primary-light:#f0f0f0;
  --accent:       #555;

  --bg:           #ffffff;
  --bg-alt:       #fafafa;
  --bg-hero:      #ffffff;
  --text:         #1a1a1a;
  --text-muted:   #777;
  --text-light:   #999;
  --text-on-dark: #1a1a1a;
  --border:       #e0e0e0;
  --shadow:       none;
  --shadow-lg:    none;

  /* Typography */
  --font-sans:  'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono:  'JetBrains Mono', 'Fira Code', monospace;

  /* Layout */
  --max-width:        1100px;
  --max-width-medium:  900px;
  --max-width-narrow:  760px;
  --section-padding:   2.5rem 0;
  --radius:            4px;
  --radius-lg:         4px;
}

/* ── Reset & Base ──────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
}

a { color: var(--text); text-decoration: underline; text-decoration-color: var(--border); text-underline-offset: 2px; transition: text-decoration-color .15s; }
a:hover { text-decoration-color: var(--text); }

img, video, iframe { max-width: 100%; display: block; border: none; }
figure { margin: 0; }

/* Lazy-load iframe placeholder */
iframe[data-src] {
  background: linear-gradient(110deg, #f5f5f5 8%, #e8e8e8 18%, #f5f5f5 33%);
  background-size: 200% 100%;
  animation: lazy-iframe-shimmer 1.5s linear infinite;
}
@keyframes lazy-iframe-shimmer {
  to { background-position-x: -200%; }
}

code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--bg-alt);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  border: 1px solid var(--border);
}
pre code { background: none; padding: 0; border: none; }

/* ── Layout ────────────────────────────────────────────────── */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}
.container-narrow {
  max-width: var(--max-width-narrow);
  margin: 0 auto;
}

.container-medium {
  max-width: var(--max-width-medium);
  margin: 0 auto;
}

.section {
  padding: var(--section-padding);
}
.section.alt-bg {
  background: var(--bg);
}

/* Video label - subtle standalone label, not a section heading */
.video-label {
  font-size: 0.875rem;
  font-weight: 500;
  color: #666;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.75rem;
  text-align: center;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.video-label::before,
.video-label::after {
  content: '';
  flex: 1;
  height: 1px;
  background: #ccc;
}

.section h2 {
  font-size: 1.725rem;
  font-weight: 600;
  text-align: left;
  margin-bottom: 1.25rem;
  color: var(--text);
  letter-spacing: 0.01em;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.section h2::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

.section h3 {
  font-size: 1.35rem;
  font-weight: 600;
  text-align: left;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  color: var(--text);
  letter-spacing: 0.01em;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.section h3::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

/* Two-column layout helper */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
  align-items: start;
}
@media (max-width: 768px) {
  .two-col { grid-template-columns: 1fr; }
}

/* ── Hero ──────────────────────────────────────────────────── */
.hero {
  background: #f7f8fa;
  color: var(--text);
  padding: 2.75rem 1.5rem 2rem;
  text-align: center;
  border-bottom: 1px solid var(--border);
}

.venue-badge {
  margin-bottom: 0.75rem;
}
.badge {
  display: inline-block;
  background: transparent;
  color: var(--text);
  font-size: 0.75rem;
  font-weight: 500;
  padding: 0.25em 0.85em;
  border-radius: 999px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin: 0 0.25rem;
  border: 1px solid var(--border);
}
.badge.accent {
  background: transparent;
  color: var(--text);
  border-color: var(--text);
}

.paper-title {
  font-size: clamp(1.5rem, 3.5vw, 2.3rem);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}
.paper-title .subtitle {
  font-weight: 400;
  opacity: 0.85;
  font-size: 0.85em;
}

/* Authors */
.author-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.3rem 1.5rem;
  margin-bottom: 0.75rem;
  font-size: 1.05rem;
}
.author a {
  color: var(--text);
  font-weight: 500;
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-color: var(--border);
}
.author a:hover { text-decoration-color: var(--text); }
.author sup {
  font-size: 0.7em;
  margin-left: 1px;
  opacity: 0.7;
}

.affiliations {
  font-size: 0.9rem;
  opacity: 0.75;
  margin-bottom: 0.35rem;
}
.affiliations span { margin: 0 0.6rem; }

.equal-contrib {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
  font-weight: 500;
  letter-spacing: 0.02em;
}

/* Link buttons */
.link-buttons {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.6rem;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.45rem 1rem;
  border-radius: var(--radius);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text);
  background: transparent;
  border: 1px solid var(--border);
  transition: border-color .15s;
  text-decoration: none;
}
.btn:hover {
  border-color: var(--text);
  text-decoration: none;
  color: var(--text);
}

/* ── Teaser ────────────────────────────────────────────────── */
.teaser-section {
  padding-top: 0;
  margin-top: 0;
  position: relative;
  z-index: 2;
}
.teaser {
  background: var(--bg);
  border-radius: 0;
  border: 1px solid var(--border);
  overflow: hidden;
}
.teaser img {
  width: 100%;
  display: block;
}
.teaser figcaption {
  padding: 0.6rem 1.25rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: center;
  border-top: 1px solid var(--border);
}

/* ── Abstract ──────────────────────────────────────────────── */
.abstract-text {
  font-size: 1rem;
  line-height: 1.65;
  text-align: justify;
}

.abstract-findings {
  font-size: 1rem;
  line-height: 1.65;
  text-align: justify;
  margin: 0.75rem 0 0.75rem 1.5rem;
  padding-left: 0.5rem;
}

.abstract-findings li {
  margin-bottom: 0.35rem;
}

/* ── Video Embed ───────────────────────────────────────────── */
.video-container {
  position: relative;
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
  padding-bottom: 56.25%; /* 16:9 */
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
}
.video-container iframe {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
}

.media-video {
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
}

/* Replay button (top-right, outside content) */
.replay-btn {
  position: absolute;
  top: -0.2rem;
  right: -0.2rem;
  padding: 0.3rem 0.9rem;
  border-radius: 999px;
  border: none;
  background: rgba(0, 0, 0, 0.15);
  color: rgba(0, 0, 0, 0.45);
  font-family: var(--font-sans);
  font-size: 0.7rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
}
.replay-btn:hover {
  background: rgba(0, 0, 0, 0.25);
  color: rgba(0, 0, 0, 0.7);
}
.replay-btn i {
  margin-right: 0.3rem;
  font-size: 0.6rem;
}

/* Section kicker — gray label above a heading */
.section-kicker {
  font-size: 1.05rem;
  color: var(--text-muted, #888);
  font-weight: 500;
  letter-spacing: 0.02em;
  margin-bottom: 0;
}
.section-kicker + h2 {
  margin-top: -0.25rem;
}

/* ── Inline citations with hover tooltip ──────────────────── */
body {
  counter-reset: cite-counter;
}
.cite {
  counter-increment: cite-counter;
  display: inline;
  position: relative;
  color: #4f46e5;
  font-size: 0.85em;
  font-weight: 500;
  cursor: pointer;
  text-decoration: none;
  border-bottom: 1px dashed rgba(79, 70, 229, 0.3);
}
.cite::before {
  content: '[' counter(cite-counter) ']';
}
.cite:hover {
  color: #3730a3;
}
.cite .cite-tooltip {
  display: none;
  position: absolute;
  bottom: calc(100% + 6px);
  left: 50%;
  transform: translateX(-50%);
  background: #1e1e2e;
  color: #e0e0e0;
  font-size: 0.75rem;
  font-weight: 400;
  line-height: 1.5;
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  white-space: nowrap;
  min-width: 300px;
  max-width: 450px;
  white-space: normal;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
  z-index: 100;
  pointer-events: none;
}
.cite .cite-tooltip::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 5px solid transparent;
  border-top-color: #1e1e2e;
}
.cite:hover .cite-tooltip {
  display: block;
}

/* ── Figures ───────────────────────────────────────────────── */
.figure-full {
  margin: 1.25rem 0;
  text-align: center;
}
.figure-full img {
  width: 100%;
  border-radius: var(--radius);
}
.figure-full figcaption,
.figure-grid figcaption {
  margin-top: 0.5rem;
  margin-bottom: 0.5rem;
  font-size: 1rem;
  color: var(--text-muted);
  text-align: center;
}

.figure-grid {
  display: grid;
  gap: 1rem;
}
.figure-grid.cols-2 { grid-template-columns: 1fr 1fr; }
.figure-grid.cols-3 { grid-template-columns: 1fr 1fr 1fr; }
.figure-grid.cols-4 { grid-template-columns: 1fr 1fr 1fr 1fr; }
@media (max-width: 768px) {
  .figure-grid.cols-3,
  .figure-grid.cols-4 { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 480px) {
  .figure-grid.cols-3,
  .figure-grid.cols-4 { grid-template-columns: 1fr; }
  .figure-grid.cols-2 { gap: 0.5rem; }
  .figure-grid.cols-2 figcaption { font-size: 0.75rem; }
}

/* Simulation scene tabs */
.sim-tabs {
  margin: 1.5rem 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--bg);
}
.sim-tab-bar {
  display: flex;
  flex-wrap: wrap;
  background: #f7f8fa;
  border-bottom: 1px solid var(--border);
  gap: 0;
}
.sim-tab-btn {
  flex: 1 1 auto;
  padding: 0.55rem 0.9rem;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
  white-space: nowrap;
  text-align: center;
}
.sim-tab-btn:hover {
  color: var(--text);
  background: rgba(0,0,0,0.02);
}
.sim-tab-btn.active {
  color: var(--text);
  border-bottom-color: var(--text);
  background: var(--bg);
}
.sim-tab-viewport {
  position: relative;
  width: 100%;
  height: 520px;
  background: #f0f2f5;
}
.sim-tab-viewport iframe {
  width: 100%;
  height: 100%;
  border: none;
  display: block;
}
.sim-tab-viewport .sim-tab-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  color: var(--text-light);
  font-size: 0.85rem;
}
@media (max-width: 768px) {
  .sim-tab-btn { font-size: 0.72rem; padding: 0.45rem 0.55rem; }
  .sim-tab-viewport { height: 380px; }
}
@media (max-width: 480px) {
  .sim-tab-viewport { height: 320px; }
}

/* ── Viewer Mode Toggle (Dataset / Policy) ─────────────────── */
.viewer-mode-toggle {
  display: flex;
  justify-content: center;
  gap: 0;
  margin-bottom: 1rem;
}
.vmt-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 10px 24px;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  background: #f7f8fa;
  border: 1px solid var(--border);
  cursor: pointer;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.vmt-btn:first-child {
  border-radius: var(--radius-lg) 0 0 var(--radius-lg);
  border-right: none;
}
.vmt-btn:last-child {
  border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
}
.vmt-btn:hover {
  background: #fff;
}
.vmt-btn.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}
.vmt-btn .vmt-icon {
  font-size: 1rem;
}
.viewer-panel.hidden {
  display: none;
}

/* ── Policy Grid Task Tabs (match sim-tab-bar style) ───────── */
.pgw-task-tabs {
  display: flex;
  flex-wrap: wrap;
  background: #f7f8fa;
  border: 1px solid var(--border);
  border-bottom: none;
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
  gap: 0;
  margin-bottom: 0;
}
.pgw-task-btn {
  flex: 1 1 auto;
  padding: 0.55rem 0.9rem;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
  white-space: nowrap;
  text-align: center;
}
.pgw-task-btn:hover {
  color: var(--text);
  background: rgba(0,0,0,0.02);
}
.pgw-task-btn.active {
  color: var(--text);
  border-bottom-color: var(--text);
  background: var(--bg);
}
.pgw-task-tabs + .policy-grid-widget {
  border-top-left-radius: 0;
  border-top-right-radius: 0;
  margin-top: 0;
  border-top: none;
}

/* ── Policy Grid Widget (BC live rollout) ──────────────────── */
.policy-grid-widget {
  position: relative;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: #f0f2f5;
  margin: 1.5rem 0;
  height: 560px;
}
.policy-grid-widget > iframe {
  width: 100%;
  height: 100%;
  border: none;
  display: block;
}
.pgw-placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-light);
  font-size: 0.85rem;
  pointer-events: none;
}
.pgw-placeholder.hidden { display: none; }

/* Floating gain grid overlay */
.pgw-float {
  position: absolute;
  top: 10px;
  left: 10px;
  z-index: 30;
  width: 180px;
  background: none;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 11px;
  color: #444;
  user-select: none;
}
.pgw-float-title {
  font-weight: 600;
  font-size: 10px;
  letter-spacing: 0.3px;
  text-transform: uppercase;
  color: #888;
  margin-bottom: 4px;
}
.pgw-float canvas {
  width: 100%;
  aspect-ratio: 1;
  display: block;
  border-radius: 4px;
  cursor: pointer;
}
.pgw-gain-vals {
  display: flex;
  justify-content: space-between;
  font-size: 10px;
  color: #888;
  padding: 2px 0 0;
}
.pgw-gain-vals b {
  color: #444;
  font-weight: 600;
}

@media (max-width: 768px) {
  .policy-grid-widget { height: 420px; }
  .pgw-float { width: 140px; padding: 6px 8px; }
}
@media (max-width: 480px) {
  .policy-grid-widget { height: 360px; }
  .pgw-float { width: 120px; top: 6px; left: 6px; }
}

/* Placeholder images (remove when replacing with real images) */
.placeholder-img {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  background: #f5f5f5;
  border-radius: var(--radius);
  color: #bbb;
  font-size: 0.8rem;
  text-align: center;
  padding: 1rem;
}
.placeholder-img i {
  font-size: 1.5rem;
  opacity: 0.4;
}

/* ── Tabs ──────────────────────────────────────────────────── */
.tab-nav {
  display: flex;
  gap: 0.25rem;
  justify-content: center;
  margin-bottom: 1rem;
  border-bottom: 2px solid var(--border);
  padding-bottom: 0;
}
.tab-btn {
  background: none;
  border: none;
  padding: 0.65rem 1.5rem;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all .2s;
  font-family: var(--font-sans);
}
.tab-btn:hover { color: var(--text); }
.tab-btn.active {
  color: var(--text);
  border-bottom-color: var(--text);
}

/* Sim / Real badges inside tab buttons */
.tab-badge {
  display: block;
  font-size: 0.6rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  line-height: 1;
  margin-bottom: 0.25rem;
  padding: 0.15rem 0.4rem;
  border-radius: 3px;
  width: fit-content;
  margin-left: auto;
  margin-right: auto;
}
.tab-badge.real {
  background: #dbeafe;
  color: #1e40af;
}
.tab-badge.sim {
  background: #fef3c7;
  color: #92400e;
}

.tab-content {
  display: none;
  animation: fadeIn .3s ease;
}
.tab-content.active { display: block; }

@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: translateY(0); } }

/* ── Gain Table ────────────────────────────────────────────── */
.gain-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}
.gain-table th,
.gain-table td {
  text-align: left;
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border);
}
.gain-table thead th {
  font-weight: 600;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
}
.gain-table code {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  background: var(--bg-alt);
  padding: 0.15rem 0.4rem;
  border-radius: 3px;
}

/* ── GitHub Embed ──────────────────────────────────────────── */
.github-embed {
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin: 0.75rem 0;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.55;
}
.github-embed-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.85rem;
  background: var(--bg-alt);
  border-bottom: 1px solid var(--border);
  font-family: var(--font-sans);
  font-size: 0.78rem;
  color: var(--text-muted);
}
.github-embed-header i {
  font-size: 0.95rem;
  color: var(--text-muted);
}
.github-embed-header a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
}
.github-embed-header a:hover {
  text-decoration: underline;
}
.github-embed-header .gh-lines {
  margin-left: auto;
  font-size: 0.72rem;
  color: var(--text-light);
}
.github-embed-code {
  display: flex;
  overflow-x: auto;
  background: #fafbfc;
}
.github-embed-lines {
  display: flex;
  flex-direction: column;
  padding: 0.65rem 0;
  text-align: right;
  user-select: none;
  background: var(--bg-alt);
  border-right: 1px solid var(--border);
  min-width: 2.5rem;
}
.github-embed-lines span {
  padding: 0 0.6rem;
  color: var(--text-light);
  font-size: 0.75rem;
  line-height: 1.55;
}
.github-embed-lines span.gh-highlight {
  background: #fff8c5;
}
.github-embed-pre {
  flex: 1;
  margin: 0;
  padding: 0.65rem 1rem;
  background: transparent;
  white-space: pre;
  overflow-x: auto;
}
.github-embed-pre .gh-highlight {
  background: #fff8c5;
  display: inline-block;
  width: 100%;
  margin: 0 -1rem;
  padding: 0 1rem;
}

/* ── Image Comparison Slider ───────────────────────────────── */
.comparison-slider {
  position: relative;
  max-width: 800px;
  margin: 1.25rem auto 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  cursor: col-resize;
  user-select: none;
  -webkit-user-select: none;
}

.comparison-before,
.comparison-after {
  width: 100%;
}
.comparison-before { clip-path: inset(0 50% 0 0); position: absolute; top: 0; left: 0; z-index: 2; }
.comparison-after  { position: relative; z-index: 1; }

.comparison-label {
  position: absolute;
  top: 10px;
  z-index: 10;
  background: rgba(0,0,0,.5);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 500;
  padding: 0.2em 0.65em;
  border-radius: 999px;
  pointer-events: none;
}
.left-label  { left:  12px; }
.right-label { right: 12px; }

.comparison-handle {
  position: absolute;
  top: 0; bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  z-index: 5;
  display: flex;
  flex-direction: column;
  align-items: center;
  pointer-events: none;
}
.handle-line {
  flex: 1;
  width: 2px;
  background: #fff;
}
.handle-circle {
  width: 36px; height: 36px;
  border-radius: 50%;
  background: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 0.85rem;
  flex-shrink: 0;
}

/* ── Video Grid ────────────────────────────────────────────── */
.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
}
.video-card {
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--bg);
  border: 1px solid var(--border);
}
.video-card:hover {
  background: var(--bg-alt);
}
.video-card video, .video-card img {
  width: 100%;
  display: block;
}
.video-caption {
  padding: 0.5rem 0.75rem;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text);
  text-align: center;
}

/* ── Carousel ──────────────────────────────────────────────── */
.gallery-carousel {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
}

.carousel-track-container {
  overflow: hidden;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
}

.carousel-track {
  display: flex;
  transition: transform .4s ease;
}

.carousel-slide {
  min-width: 100%;
  flex-shrink: 0;
}
.carousel-slide img {
  width: 100%;
  display: block;
}
.slide-caption {
  padding: 0.6rem 1.25rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: center;
  background: var(--bg);
}

.carousel-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-70%);
  z-index: 10;
  width: 36px; height: 36px;
  border-radius: 50%;
  background: rgba(255,255,255,.9);
  border: 1px solid var(--border);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background .15s;
  color: var(--text);
  font-size: 0.9rem;
}
.carousel-btn:hover { background: #fff; }
.carousel-btn.prev { left: -20px; }
.carousel-btn.next { right: -20px; }
@media (max-width: 960px) {
  .carousel-btn.prev { left: 8px; }
  .carousel-btn.next { right: 8px; }
}

.carousel-dots {
  display: flex;
  justify-content: center;
  gap: 0.4rem;
  margin-top: 0.75rem;
}
.carousel-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--border);
  border: none;
  cursor: pointer;
  transition: background .2s;
}
.carousel-dot.active { background: var(--text); }

/* ── Results Table ─────────────────────────────────────────── */
.table-wrapper {
  max-width: 800px;
  margin: 0 auto;
  overflow-x: auto;
}
.results-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}
.results-table th,
.results-table td {
  padding: 0.5rem 1rem;
  text-align: center;
  border-bottom: 1px solid var(--border);
}
.results-table th {
  background: var(--bg-alt);
  font-weight: 600;
  color: var(--text);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.results-table td:first-child,
.results-table th:first-child {
  text-align: left;
}
.results-table .highlight-row {
  background: var(--primary-light);
}
.results-table .highlight-row td {
  color: var(--text);
}
.table-caption {
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: center;
}

/* ── Embed Container ───────────────────────────────────────── */
.embed-container {
  max-width: 900px;
  margin: 1rem auto 0;
}

/* ── BibTeX ────────────────────────────────────────────────── */
.bibtex-block {
  position: relative;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  overflow-x: auto;
}
.bibtex-block pre {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.6;
  color: var(--text);
  white-space: pre-wrap;
  word-break: break-word;
}
.copy-btn {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 0.3rem 0.75rem;
  border-radius: var(--radius);
  font-size: 0.75rem;
  cursor: pointer;
  transition: border-color .15s;
  font-family: var(--font-sans);
}
.copy-btn:hover { border-color: var(--text); color: var(--text); }
.copy-btn.copied {
  background: #22c55e;
  border-color: #22c55e;
  color: #fff;
}

/* ── Gain-Tuning Poll ───────────────────────────────────────── */
#poll,
#learning-poll {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.04) 0%, rgba(139, 92, 246, 0.06) 100%);
  border-top: 1px solid rgba(99, 102, 241, 0.08);
  border-bottom: 1px solid rgba(99, 102, 241, 0.08);
  padding: 1.5rem 0;
}
/* Poll section background pulse (before any selection) */
/* Poll section — flowing gradient of all three option colors */
@keyframes pollGradientFlow {
  0%   { background-position: 0% 50%; }
  50%  { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}
#poll,
#learning-poll {
  position: relative;
  overflow: hidden;
}
#poll {
  background: linear-gradient(
    135deg,
    rgba(123, 63, 141, 0.14),
    rgba(74, 127, 181, 0.14),
    rgba(74, 122, 62, 0.14),
    rgba(74, 127, 181, 0.14),
    rgba(123, 63, 141, 0.14)
  );
  background-size: 300% 300%;
  animation: pollGradientFlow 6s ease-in-out infinite;
}
#poll.poll-chosen {
  animation: none;
  background: transparent;
}

/* Learning poll section — flowing gradient */
#learning-poll {
  background: linear-gradient(
    135deg,
    rgba(217, 119, 6, 0.14),
    rgba(13, 148, 136, 0.14),
    rgba(99, 102, 241, 0.14),
    rgba(13, 148, 136, 0.14),
    rgba(217, 119, 6, 0.14)
  );
  background-size: 300% 300%;
  animation: pollGradientFlow 6s ease-in-out infinite;
}
#learning-poll.lp-chosen {
  animation: none;
  background: transparent;
}

/* ── Color spill effect (expands from clicked card) ──────────── */
@keyframes colorSpill {
  0%   { transform: translate(-50%, -50%) scale(0); opacity: 0.6; }
  60%  { opacity: 0.5; }
  100% { transform: translate(-50%, -50%) scale(1); opacity: 0.45; }
}
#poll::after,
#learning-poll::after {
  content: '';
  position: absolute;
  /* Size large enough to cover the section from any origin */
  width: 200%;
  height: 500%;
  border-radius: 50%;
  pointer-events: none;
  top: var(--spill-y, 50%);
  left: var(--spill-x, 50%);
  transform: translate(-50%, -50%) scale(0);
  opacity: 0;
  z-index: 0;
}
#poll.poll-chosen::after {
  animation: colorSpill 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94) forwards;
}
#poll.poll-chosen-a::after { background: radial-gradient(circle, rgba(123, 63, 141, 0.35), rgba(123, 63, 141, 0.10) 70%); }
#poll.poll-chosen-b::after { background: radial-gradient(circle, rgba(74, 127, 181, 0.35), rgba(74, 127, 181, 0.10) 70%); }
#poll.poll-chosen-c::after { background: radial-gradient(circle, rgba(74, 122, 62, 0.35), rgba(74, 122, 62, 0.10) 70%); }

#learning-poll.lp-chosen::after {
  animation: colorSpill 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94) forwards;
}
#learning-poll.lp-chosen-bc::after       { background: radial-gradient(circle, rgba(217, 119, 6, 0.35), rgba(217, 119, 6, 0.10) 70%); }
#learning-poll.lp-chosen-rl::after       { background: radial-gradient(circle, rgba(13, 148, 136, 0.35), rgba(13, 148, 136, 0.10) 70%); }
#learning-poll.lp-chosen-sim2real::after { background: radial-gradient(circle, rgba(99, 102, 241, 0.35), rgba(99, 102, 241, 0.10) 70%); }

/* Hover overlay — set via --hover-color JS variable, fades gently */
#poll::before,
#learning-poll::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--hover-color, transparent);
  opacity: var(--hover-opacity, 0);
  transition: opacity 0.6s ease, background 0.6s ease;
  pointer-events: none;
  z-index: 0;
}

/* Keep poll content above the pseudo-elements */
#poll > *,
#learning-poll > * {
  position: relative;
  z-index: 1;
}

/* "Take me to" jump button */
.poll-jump-btn {
  display: block;
  margin: 1rem auto 0;
  padding: 0.6rem 1.5rem;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text);
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1.5px solid rgba(0, 0, 0, 0.1);
  border-radius: 999px;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.2s, opacity 0.3s;
  opacity: 0;
  z-index: 2;
  position: relative;
}
.poll-jump-btn.visible {
  opacity: 1;
}
.poll-jump-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}
.poll-jump-btn em {
  font-style: italic;
}
.poll-jump-btn i {
  margin-left: 0.4rem;
  font-size: 0.75rem;
  opacity: 0.5;
}

.poll-box {
  text-align: center;
  padding: 0.5rem 0 0.5rem;
}
.poll-onboarding {
  font-size: 0.95rem;
  color: var(--text);
  letter-spacing: 0.01em;
  margin-bottom: -0.1rem;
}
.poll-question {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
  /* Override default h2 flex heading line */
  display: block;
  text-align: center;
  justify-content: center;
}
.poll-question::after { display: none; }
.poll-subtitle {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-top: 1rem;
  margin-bottom: 0.5rem;
}
.poll-options {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.75rem;
  max-width: 960px;
  margin: 0 auto;
}
.poll-card {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 1rem;
  background: var(--bg);
  border: 2px solid var(--border);
  border-radius: 12px;
  padding: 1rem 1.25rem;
  width: 100%;
  cursor: pointer;
  transition: border-color .4s ease, transform .15s, box-shadow .2s, background .4s ease;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.4;
  color: var(--text);
}

/* Card hover / selected states */
.poll-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 4px 16px rgba(0,0,0,.08);
}
.poll-card.selected {
  transform: translateY(-3px);
  box-shadow: 0 4px 16px rgba(0,0,0,.08);
}
.poll-card[data-poll="a"]:hover,
.poll-card[data-poll="a"].selected { border-color: #7b3f8d; }
.poll-card[data-poll="b"]:hover,
.poll-card[data-poll="b"].selected { border-color: #4a7fb5; }
.poll-card[data-poll="c"]:hover,
.poll-card[data-poll="c"].selected { border-color: #4a7a3e; }
.poll-card[data-poll="d"]:hover,
.poll-card[data-poll="d"].selected { border-color: #888; }
.poll-options.has-selection .poll-card:not(.selected) {
  opacity: 0.5;
}

/* Avatar icon (matching the provided image) */
.poll-avatar {
  position: relative;
  width: 52px;
  height: 52px;
  min-width: 52px;
  border-radius: 50%;
  border: 2.5px solid currentColor;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-end;
  overflow: hidden;
}
.poll-avatar.purple { color: #7b3f8d; }
.poll-avatar.blue   { color: #4a7fb5; }
.poll-avatar.green  { color: #4a7a3e; }
.poll-avatar.gray   { color: #888; }
.poll-avatar .avatar-head {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: currentColor;
  position: absolute;
  top: 10px;
}
.poll-avatar .avatar-body {
  width: 30px;
  height: 16px;
  border-radius: 15px 15px 0 0;
  background: currentColor;
  position: absolute;
  bottom: 3px;
}
.poll-avatar .avatar-label {
  position: absolute;
  top: 12px;
  font-size: 0.55rem;
  font-weight: 700;
  color: #fff;
  z-index: 1;
}

.poll-card-text {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  min-width: 0;
}
.poll-card-title {
  font-weight: 600;
  font-size: 1.0rem;
  display: block;
  text-align: left;
}
.poll-card[data-poll="a"] .poll-card-title { color: #7b3f8d; }
.poll-card[data-poll="b"] .poll-card-title { color: #4a7fb5; }
.poll-card[data-poll="c"] .poll-card-title { color: #4a7a3e; }
.poll-card[data-poll="d"] .poll-card-title { color: #888; }
.poll-card-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.45;
  text-align: left;
}

/* Reset / change answer link */
.poll-reset {
  display: none;
  margin: 1rem auto 0;
  background: none;
  border: none;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  color: var(--text-light);
  cursor: pointer;
  padding: 0.25rem 0.5rem;
  transition: color .15s;
}
.poll-reset:hover {
  color: var(--text);
}
.poll-reset.visible {
  display: block;
}

/* Copy-link / share button */
.poll-share-btn {
  display: none;
  margin: 0.35rem auto 0;
  background: none;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  color: var(--text-light);
  cursor: pointer;
  padding: 0.3rem 0.85rem;
  transition: color .15s, border-color .15s, background .15s;
}
.poll-share-btn:hover {
  color: var(--text);
  border-color: var(--text-muted);
}
.poll-share-btn.visible {
  display: block;
}
.poll-share-btn.copied {
  color: #16a34a;
  border-color: #16a34a;
}

/* Response panels */
.poll-response {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transition: max-height .5s ease, opacity .4s ease, margin .4s ease;
  margin-top: 0;
  border-left: 3px solid var(--border);
  padding: 0 1.25rem;
}
.poll-response.visible {
  max-height: 400px;
  opacity: 1;
  margin-top: 1.75rem;
  padding: 1rem 1.25rem;
}
.poll-response-header {
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
}
.poll-response-header.purple { color: #7b3f8d; }
.poll-response-header.blue   { color: #4a7fb5; }
.poll-response-header.green  { color: #4a7a3e; }
.poll-response-header.gray   { color: #888; }
.poll-response.visible { border-left-color: var(--border); }
#poll-response-a.visible { border-left-color: #7b3f8d; }
#poll-response-b.visible { border-left-color: #4a7fb5; }
#poll-response-c.visible { border-left-color: #4a7a3e; }
#poll-response-d.visible { border-left-color: #888; }
.poll-response p {
  font-size: 1.0rem;
  line-height: 1.65;
  color: var(--text);
}

/* ── Poll Vote Bars (live Supabase results) ────────────────── */
.poll-vote-bar {
  display: none;
  margin-top: 0.5rem;
  position: relative;
  height: 22px;
  background: #f0f0f0;
  border-radius: 11px;
  overflow: hidden;
}
.poll-vote-bar.visible {
  display: block;
}
.poll-vote-fill {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  border-radius: 11px;
  width: 0;
  transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1);
  background: rgba(0, 0, 0, 0.06);
}
.poll-vote-label {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  height: 100%;
  padding: 0 0.75rem;
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--text-muted);
  white-space: nowrap;
}
/* Per-option fill colors (gain poll) */
.poll-card[data-poll="a"] .poll-vote-fill { background: rgba(123, 63, 141, 0.15); }
.poll-card[data-poll="b"] .poll-vote-fill { background: rgba(74, 127, 181, 0.15); }
.poll-card[data-poll="c"] .poll-vote-fill { background: rgba(74, 122, 62, 0.15); }
/* Per-option fill colors (learning poll) */
.lp-card[data-lp="bc"]       .poll-vote-fill { background: rgba(217, 119, 6, 0.15); }
.lp-card[data-lp="rl"]       .poll-vote-fill { background: rgba(13, 148, 136, 0.15); }
.lp-card[data-lp="sim2real"]  .poll-vote-fill { background: rgba(99, 102, 241, 0.15); }

/* ── Poll Locked Mode (after voting — unclickable) ─────────── */
.poll-locked .poll-card {
  pointer-events: none;
  cursor: default;
  opacity: 0.45;
  animation: none !important;
  transform: none !important;
  box-shadow: none !important;
}
.poll-locked .poll-card.selected {
  opacity: 1;
  border-width: 2.5px;
}

@media (max-width: 640px) {
  .poll-options { grid-template-columns: 1fr; }
  .poll-card { padding: 0.85rem 1rem; }
}

/* ── Learning-Algorithm Poll (second poll, shared) ─────────── */
/* Three-column grid for 3 options */
.lp-options {
  grid-template-columns: 1fr 1fr 1fr !important;
}
@media (max-width: 780px) {
  .lp-options { grid-template-columns: 1fr !important; }
}

/* Avatar & title colors */
.poll-avatar.lp-orange  { color: #d97706; }
.poll-avatar.lp-teal    { color: #0d9488; }
.poll-avatar.lp-indigo  { color: #6366f1; }

.lp-card-no-avatar {
  padding: 1.25rem 1.5rem;
}

.lp-title-bc       { color: #d97706 !important; }
.lp-title-rl       { color: #0d9488 !important; }
.lp-title-sim2real  { color: #6366f1 !important; }



/* Card border colors on hover */
.lp-card[data-lp="bc"]:hover       { border-color: #d97706; }
.lp-card[data-lp="rl"]:hover       { border-color: #0d9488; }
.lp-card[data-lp="sim2real"]:hover { border-color: #6366f1; }
/* Selected: colored border + subtle tinted background */
.lp-card[data-lp="bc"].selected       { border-color: #d97706; background: rgba(217, 119, 6, 0.05); }
.lp-card[data-lp="rl"].selected       { border-color: #0d9488; background: rgba(13, 148, 136, 0.05); }
.lp-card[data-lp="sim2real"].selected { border-color: #6366f1; background: rgba(99, 102, 241, 0.05); }

/* Response header colors */
.lp-header-orange { color: #d97706; }
.lp-header-teal   { color: #0d9488; }
.lp-header-indigo { color: #6366f1; }

/* Response border colors */
#lp-response-bc.visible       { border-left-color: #d97706; }
#lp-response-rl.visible       { border-left-color: #0d9488; }
#lp-response-sim2real.visible { border-left-color: #6366f1; }

/* ── Dynamic content containers ────────────────────────────── */
#lp-dynamic-content,
#poll-dynamic-content {
  overflow-anchor: none;
}

/* "What if you relied on …" subtle label above next section */
.lp-also-label,
.choice-also-label {
  max-width: var(--max-width-medium);
  margin: 2.5rem auto -2rem;
  padding: 0 1.5rem;
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text-light);
  letter-spacing: 0.02em;
}

/* ── Footer ────────────────────────────────────────────────── */
.footer {
  padding: 1.25rem 1.5rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-light);
  border-top: 1px solid var(--border);
}

/* ── Sticky Header ─────────────────────────────────────────── */
.sticky-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 200;
  background: #f7f8fa;
  border-bottom: 1px solid var(--border);
  transform: translateY(-100%);
  opacity: 0;
  transition: transform .35s ease, opacity .35s ease;
  pointer-events: none;
}
.sticky-header.visible {
  transform: translateY(0);
  opacity: 1;
  pointer-events: auto;
}
.sticky-header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0.5rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.sticky-title {
  font-size: 0.82rem;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  line-height: 1.4;
}
.sticky-title strong {
  font-weight: 600;
}
.sticky-sep {
  color: var(--text-light);
  margin: 0 0.25rem;
}
.sticky-authors {
  color: var(--text-muted);
  font-weight: 400;
}
.sticky-venue {
  color: var(--text-light);
  font-weight: 400;
}
.sticky-links {
  display: flex;
  gap: 0.35rem;
  flex-shrink: 0;
}
.sticky-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.75rem;
  text-decoration: none;
  transition: border-color .15s, color .15s;
}
.sticky-btn:hover {
  border-color: var(--text);
  color: var(--text);
  text-decoration: none;
}

@media (max-width: 640px) {
  .sticky-authors, .sticky-venue, .sticky-sep:nth-child(n+3) {
    display: none;
  }
}

/* ── Table of Contents — floating card on right ────────────── */
.dynamic-toc {
  position: fixed;
  top: 58%;
  right: 1.5rem;
  transform: translateY(-50%);
  z-index: 100;
  max-height: 75vh;
  overflow-y: auto;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(0, 0, 0, 0.08);
  border-radius: 0.75rem;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.07), 0 1px 4px rgba(0, 0, 0, 0.04);
  padding: 0.75rem 0;
  min-width: 13rem;
}
.dynamic-toc .toc-title {
  display: block;
  padding: 0.15rem 1rem 0.55rem;
  font-size: 0.6rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-lighter, #999);
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
  margin-bottom: 0.35rem;
}
.dynamic-toc ul {
  list-style: none;
  margin: 0;
  padding: 0;
}
.dynamic-toc li {
  margin: 0;
}
.dynamic-toc a {
  display: block;
  padding: 0.35rem 1rem 0.35rem 0.85rem;
  font-size: 0.73rem;
  color: var(--text-light);
  text-decoration: none;
  line-height: 1.4;
  transition: color .2s, background .2s, border-color .2s;
  border-left: 2.5px solid transparent;
}
.dynamic-toc a:hover {
  color: var(--text);
  background: rgba(99, 102, 241, 0.06);
  text-decoration: none;
}
.dynamic-toc a.active {
  color: #4f46e5;
  border-left-color: #4f46e5;
  font-weight: 600;
  background: rgba(99, 102, 241, 0.08);
}
.dynamic-toc .toc-sub a {
  font-size: 0.73rem;
  padding-left: 1.6rem;
  color: var(--text-lighter, #aaa);
}
.dynamic-toc .toc-sub a:hover {
  color: var(--text-light);
  background: rgba(99, 102, 241, 0.04);
}
.dynamic-toc .toc-sub a.active {
  color: #4f46e5;
  border-left-color: #4f46e5;
  font-weight: 600;
  background: rgba(99, 102, 241, 0.08);
}
/* Collapsed placeholder sub-items (hidden until user makes a choice) */
.dynamic-toc .toc-collapsed {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  margin: 0;
  padding: 0;
  pointer-events: none;
  user-select: none;
  transition: filter 0.4s ease, opacity 0.4s ease;
}

/* Hide TOC when viewport is too narrow for it to not overlap content */
@media (max-width: 1400px) {
  .dynamic-toc { display: none; }
}

/* ── "How?" Button (figcaption) ─────────────────────────────── */
.how-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  margin-left: 0.5rem;
  padding: 0.2rem 0.6rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 1rem;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
  vertical-align: middle;
}
.how-btn:hover {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

/* ── Info Modal ────────────────────────────────────────────── */
.info-modal-overlay {
  position: fixed;
  inset: 0;
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.45);
  backdrop-filter: blur(4px);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.25s, visibility 0.25s;
}
.info-modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.info-modal {
  position: relative;
  background: var(--bg);
  border-radius: var(--radius-lg);
  padding: 2rem 2.25rem;
  max-width: 600px;
  width: 90%;
  max-height: 80vh;
  overflow-y: auto;
  box-shadow: 0 12px 40px rgba(0,0,0,0.15);
  transform: translateY(20px) scale(0.97);
  transition: transform 0.25s;
}
.info-modal-overlay.active .info-modal {
  transform: translateY(0) scale(1);
}

.info-modal h3 {
  margin-bottom: 0.75rem;
  font-size: 1.15rem;
}

.info-modal p {
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 0.75rem;
}

.info-modal-close {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  background: none;
  border: none;
  font-size: 1.2rem;
  color: var(--text-muted);
  cursor: pointer;
  padding: 0.25rem;
  line-height: 1;
  transition: color 0.2s;
}
.info-modal-close:hover {
  color: var(--text);
}

/* ── Responsive ────────────────────────────────────────────── */
@media (max-width: 640px) {
  .hero { padding: 2rem 1rem 1.5rem; }
  .section { padding: 1.75rem 0; }
  .section h2 { font-size: 1.5rem; }
  .section h3 { font-size: 1.1rem; }
  .link-buttons { gap: 0.4rem; }
  .btn { font-size: 0.8rem; padding: 0.45rem 0.9rem; }
  .author-list { font-size: 0.95rem; gap: 0.2rem 1rem; }

  /* Justified text creates huge word-gaps on narrow screens */
  .abstract-text,
  .abstract-findings { text-align: left; }
  .abstract-findings { margin-left: 1.1rem; padding-left: 0.25rem; }

  /* Tighten section container gutters on phones */
  .container { padding: 0 1rem; }

  /* Display math (KaTeX) can overflow the viewport — allow horizontal scroll */
  .katex-display {
    overflow-x: auto;
    overflow-y: hidden;
    padding: 0.25rem 0;
    -webkit-overflow-scrolling: touch;
  }
  .katex-display > .katex { white-space: nowrap; }

  /* YouTube / video summary iframe: use 16:9 instead of fixed height */
  .video-collapse iframe {
    height: auto !important;
    aspect-ratio: 16 / 9;
  }

  /* Interactive widget iframes: trim heights on mobile.
     Internal responsive CSS in each widget handles layout reflow. */
  #mujoco-iframe { height: 440px !important; }
  iframe[src*="pd_response_widget"],
  iframe[data-src*="pd_response_widget"] { height: 340px !important; }

  /* KaTeX's hidden MathML layer can leak a few px past the viewport on
     narrow screens and cause horizontal page scroll — clip it at the root */
  html, body { overflow-x: hidden; }

  /* Replay video wrappers use inline width:80% — expand to full on mobile */
  .replay-video-wrap .replay-video { width: 100% !important; }

  /* MIT logo in affiliations can be a touch smaller */
  .affiliations img { height: 34px !important; }

  /* Library tabs: allow horizontal scroll, tighter padding */
  .tab-nav {
    justify-content: flex-start;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    flex-wrap: nowrap;
    scrollbar-width: none;
  }
  .tab-nav::-webkit-scrollbar { display: none; }
  .tab-btn {
    padding: 0.55rem 0.75rem;
    font-size: 0.82rem;
    white-space: nowrap;
    flex-shrink: 0;
  }
  .tab-badge { font-size: 0.55rem; padding: 0.1rem 0.35rem; }

  /* Poll section: tighten for mobile */
  .poll-box { padding: 0.5rem 0; }
  .poll-onboarding { font-size: 0.85rem; margin-bottom: 0.35rem; }
  .poll-subtitle { font-size: 0.8rem; margin-top: 0.75rem; }
  h2.poll-question { font-size: 1.2rem; line-height: 1.3; margin-bottom: 0.9rem; }
  .poll-options { gap: 0.5rem; }
  .poll-card { padding: 0.6rem 0.85rem; }
  .poll-card-title { font-size: 0.95rem; margin-bottom: 0.2rem; }
  .poll-card-desc { font-size: 0.8rem; line-height: 1.4; }
}

/* ── Print ─────────────────────────────────────────────────── */
@media print {
  .hero { background: #f7f8fa; color: #000; }
  .btn, .copy-btn, .carousel-btn { display: none; }
  .section.alt-bg { background: #fff; }
}

/* ── Utility Classes ───────────────────────────────────────── */
.text-center { text-align: center; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 2rem; }
.hidden { display: none !important; }