/* ── Reset & base ────────────────────────────────────────────── */
* {
  box-sizing: border-box;
  text-shadow: none !important;
  -webkit-text-stroke: 0 !important;
}

body {
  margin: 0;
  color: #1a1a2e;
  background: #fff;
  font-family: "Segoe UI", Arial, Helvetica, sans-serif;
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: geometricPrecision;
}

main {
  width: min(980px, calc(100% - 36px));
  margin: 0 auto;
  padding: 38px 0 80px;
}

/* ── Section backgrounds ─────────────────────────────────────── */
.section-alt {
  background: #f5f8fd;
  margin-left: calc(-50vw + 50%);
  margin-right: calc(-50vw + 50%);
  padding-left: calc(50vw - 50%);
  padding-right: calc(50vw - 50%);
}
.section-alt > * {
  max-width: 980px;
  margin-left: auto;
  margin-right: auto;
}

/* ── Inline colour highlights ────────────────────────────────── */
.hl-red,
.hl-blue,
.hl-green {
  font-weight: 650;
}

.hl-red {
  color: #C41230;
}

.hl-blue {
  color: #0b5cab;
}

.hl-green {
  color: #2d7a2d;
}

/* ── Tags / badges ───────────────────────────────────────────── */
.tag {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 12px;
  font-size: 0.82rem;
  font-weight: 600;
  margin: 2px 3px;
}
.tag-gray  { background: #eee;    color: #444; }
.tag-blue  { background: #ddeeff; color: #0b5cab; }
.tag-green { background: #e4f5e4; color: #2d7a2d; }
.tag-red   { background: #fde8ec; color: #C41230; }

/* ── Header ──────────────────────────────────────────────────── */
.page-header { margin: 0 auto 34px; }

.header-main {
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}

.venue {
  margin: 0 0 10px;
  font-size: 0.9rem;
  color: #888;
  letter-spacing: 0.03em;
}

h1 {
  max-width: 800px;
  margin: 0 auto 0;
  font-size: clamp(1.65rem, 3.4vw, 2.5rem);
  line-height: 1.15;
  font-weight: 650;
  color: #000;
}

.authors {
  margin: 20px auto 6px;
  max-width: 820px;
  font-size: 1.05rem;
  color: #333;
}

.affiliation {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  color: #555;
}

.cmu-logo {
  height: 35px;
  width: auto;
  max-width: none;
  object-fit: contain;
  display: inline;
  vertical-align: middle;
}

.note { margin: 4px 0; color: #888; font-size: 0.9rem; }

/* ── Link buttons ────────────────────────────────────────────── */
.links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin: 22px 0 10px;
}

.links a {
  display: inline-block;
  padding: 8px 18px;
  border: 1.5px solid #b9c9d8;
  border-radius: 6px;
  text-decoration: none;
  background: #f8fbfd;
  color: #0b5cab;
  font-size: 0.95rem;
  font-weight: 500;
  transition: background 0.15s, border-color 0.15s;
}
.links a:hover { background: #e8f2ff; border-color: #0b5cab; }

/* ── TOC nav ─────────────────────────────────────────────────── */
.toc {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 6px;
  margin: 14px auto 6px;
  font-size: 0.9rem;
}
.toc a {
  color: #555;
  text-decoration: none;
  padding: 3px 10px;
  border-radius: 4px;
  transition: background 0.15s;
}
.toc a:hover { background: #f0f0f0; color: #C41230; }

/* ── Section headings ────────────────────────────────────────── */
section { margin-top: 52px; padding-top: 8px; }
.section-alt { padding-top: 40px; padding-bottom: 40px; margin-top: 52px; }

h2 {
  margin: 0 0 6px;
  font-size: 1.75rem;
  font-weight: 700;
  color: #0f0f23;
  padding-bottom: 10px;
  border-bottom: 3px solid #C41230;
  display: inline-block;
}

/* force h2 to block so border spans full line */
h2 { display: block; border-bottom: none; position: relative; }
h2::after {
  content: "";
  display: block;
  width: 52px;
  height: 3px;
  background: #C41230;
  margin-top: 6px;
  border-radius: 2px;
}

.section-sub {
  margin: 26px 0 6px;
  font-size: 1.12rem;
  font-weight: 600;
  color: #1a1a2e;
  padding-left: 12px;
  border-left: 3px solid #0b5cab;
}

h4 {
  margin: 20px 0 4px;
  font-size: 0.98rem;
  font-weight: 600;
  color: #333;
}

.improvement-heading {
  margin: 22px 0 6px;
  font-size: 1.08rem;
  font-weight: 600;
  color: #333;
}

h3 { margin: 22px 0 6px; font-size: 1.08rem; color: #333; }

p { margin: 0 0 14px; }

a { color: #0b5cab; }

/* ── Video section ───────────────────────────────────────────── */
.video-section { margin-top: 28px; padding-top: 0; }

video {
  display: block;
  width: 90%;
  max-width: 840px;
  max-height: min(480px, 52vh);
  aspect-ratio: 16 / 9;
  margin: 16px auto;
  background: #000;
  border: 1px solid #ddd;
  border-radius: 6px;
  object-fit: contain;
}

/* ── Stats grid ──────────────────────────────────────────────── */
.stat-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0;
  margin: 28px 0 8px;
  border: 1px solid #dde6f0;
  border-radius: 10px;
  overflow: hidden;
  background: #f0f6ff;
}

.stat-item {
  flex: 1 1 140px;
  text-align: center;
  padding: 20px 14px;
  border-right: 1px solid #dde6f0;
}
.stat-item:last-child { border-right: none; }

.stat-number {
  display: block;
  font-size: 2.3rem;
  font-weight: 700;
  color: #C41230;
  line-height: 1.1;
}

.stat-label {
  display: block;
  font-size: 0.78rem;
  color: #666;
  margin-top: 4px;
  line-height: 1.3;
}

/* ── Contribution list ───────────────────────────────────────── */
.contribution-list {
  list-style: none;
  padding: 0;
  margin: 14px 0 20px;
}
.contribution-list li {
  padding: 9px 12px 9px 34px;
  position: relative;
  border-left: 3px solid #C41230;
  background: #fffafb;
  margin-bottom: 8px;
  border-radius: 0 6px 6px 0;
  font-size: 0.97rem;
}
.contribution-list li::before {
  content: "▶";
  position: absolute;
  left: 10px;
  top: 11px;
  color: #C41230;
  font-size: 0.7rem;
}

/* ── Component cards ─────────────────────────────────────────── */
.component-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 24px 0;
}
.component-card {
  background: #fff;
  border: 1px solid #dde6f0;
  border-radius: 8px;
  padding: 18px 20px;
  position: relative;
}
.component-card h4 {
  margin: 0 0 8px;
  font-size: 1rem;
  color: #0f0f23;
}
.comp-label {
  display: inline-block;
  background: #C41230;
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 1px 7px;
  border-radius: 3px;
  margin-bottom: 8px;
  letter-spacing: 0.05em;
}

/* ── Demo cards ──────────────────────────────────────────────── */
.demo-card {
  background: #fff;
  border: 1px solid #dde6f0;
  border-radius: 10px;
  padding: 24px 26px;
  margin: 20px 0;
}
.demo-card h3 {
  margin: 0 0 12px;
  font-size: 1.08rem;
  font-weight: 700;
  color: #0f0f23;
  padding-bottom: 10px;
  border-bottom: 1px solid #eee;
}

/* ── Result table colours ────────────────────────────────────── */
.result-good { color: #2d7a2d; font-weight: 600; }
.result-bad  { color: #b94a00; }
.method-label { font-weight: 500; font-size: 0.95rem; }
.method-good  { color: #2d7a2d; }

/* ── Figures ─────────────────────────────────────────────────── */
figure { margin: 22px 0 28px; }

img:not(.cmu-logo) {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 0 auto;
}

figcaption {
  margin-top: 10px;
  font-size: 0.9rem;
  text-align: center;
  color: #555;
  line-height: 1.5;
}

/* ── Acknowledgments ─────────────────────────────────────────── */
.ack-logo-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 32px;
  margin-top: 18px;
  padding: 18px 0;
}

.ack-logo-row img {
  max-width: min(260px, 42vw);
  max-height: 96px;
  object-fit: contain;
}

.wide-figure,
section > figure,
.demo-card figure,
.skill-grid figure {
  padding: 10px;
  border: 1px solid #e4e8f0;
  border-radius: 6px;
  background: #fafbfd;
}

.wide-figure { margin-top: 28px; }

.small-figure {
  max-width: 65%;
  margin-left: auto;
  margin-right: auto;
}

/* ── Skill grid ──────────────────────────────────────────────── */
.skill-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin: 20px 0 8px;
}
.skill-grid figure {
  margin: 0;
  padding: 14px;
}
.skill-grid img {
  width: 100%;
  min-height: 190px;
  object-fit: contain;
}
.skill-grid figcaption {
  font-size: 0.98rem;
  font-weight: 600;
}

/* ── Structure grid ──────────────────────────────────────────── */
.structure-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin-top: 18px;
}
.structure-grid figure { margin: 0; }
.structure-grid img {
  width: 100%;
  aspect-ratio: 1;
  object-fit: contain;
}

/* ── Table ───────────────────────────────────────────────────── */
.table-wrap { overflow-x: auto; margin-top: 16px; }

table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
}

th, td {
  padding: 10px 12px;
  border: 1px solid #dde;
  text-align: left;
  vertical-align: middle;
  font-size: 0.95rem;
}

th { background: #f0f4f8; font-weight: 600; color: #0f0f23; }
tr:hover td { background: #f9fbff; }

/* ── Code / citation ─────────────────────────────────────────── */
pre {
  overflow-x: auto;
  padding: 16px;
  border: 1px solid #dde;
  border-radius: 6px;
  background: #f7f8fb;
  font-size: 0.88rem;
  line-height: 1.6;
}

.small { color: #777; font-size: 0.88rem; margin-top: 8px; }

code { font-size: 0.9em; background: #f0f0f0; padding: 1px 4px; border-radius: 3px; }
pre code { background: none; padding: 0; }

/* ── Responsive ──────────────────────────────────────────────── */
@media (max-width: 760px) {
  body { font-size: 16px; }

  main {
    width: min(100% - 24px, 980px);
    padding-top: 24px;
  }

  .component-grid {
    grid-template-columns: 1fr;
  }

  .structure-grid,
  .skill-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .stat-grid { flex-direction: column; }
  .stat-item { border-right: none; border-bottom: 1px solid #dde6f0; }
  .stat-item:last-child { border-bottom: none; }

  .small-figure { max-width: 100%; }

  .demo-card { padding: 16px; }

  .section-alt {
    margin-left: -12px;
    margin-right: -12px;
    padding-left: 12px;
    padding-right: 12px;
  }
}