/* RoboPRO project page — engineering classic / CVPR-style aesthetic. */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
  --bg:        #ffffff;
  --bg-soft:   #f7f7f8;
  --bg-rule:   #ececec;
  --ink:       #111315;
  --ink-2:     #2c3033;
  --muted:     #6b7177;
  --rule:      #e3e5e7;
  --rule-2:    #cdd1d4;
  --accent:    #1d4eb8;
  --accent-2:  #15397f;
  --accent-soft:#eaf0fb;
  --warn:      #b03030;
  --sans:  'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  --mono:  'JetBrains Mono', ui-monospace, 'SF Mono', Menlo, Consolas, monospace;
  --maxw: 1600px;
  --shadow-1: 0 1px 0 rgba(0,0,0,0.04), 0 8px 28px -18px rgba(0,0,0,0.18);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 1.75rem;
}

/* ============ Header / Title ============ */

.site-header {
  border-bottom: 1px solid var(--rule);
  padding: 3.25rem 0 1.5rem;
}

.eyebrow {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 0.9rem;
}

h1.title {
  font-family: var(--sans);
  font-weight: 800;
  font-size: clamp(2.25rem, 5vw, 3.6rem);
  line-height: 1.05;
  letter-spacing: -0.02em;
  margin: 0;
  color: var(--ink);
}
h1.title .accent { color: var(--accent); }
h1.title .title-logo {
  display: block;
  max-height: clamp(144px, 15vw, 240px);
  width: auto;
  max-width: 100%;
  height: auto;
}

.tagline {
  margin: 0.6rem 0 0;
  color: var(--ink-2);
  font-size: clamp(1rem, 1.4vw, 1.15rem);
}

.byline {
  margin-top: 1.25rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--muted);
  letter-spacing: 0.04em;
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
}
.byline a { color: var(--ink); }
.byline strong { color: var(--ink); font-weight: 600; }

/* Prominent hero action buttons (Install / Code / Dataset) on their own line */
.hero-actions {
  margin-top: 1.5rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45em;
  padding: 0.65rem 1.25rem;
  border-radius: 8px;
  font-family: var(--sans);
  font-size: 0.98rem;
  font-weight: 600;
  letter-spacing: 0;
  text-decoration: none;
  border: 1px solid transparent;
  transition: background 0.15s ease, border-color 0.15s ease, box-shadow 0.15s ease, transform 0.05s ease;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
  box-shadow: var(--shadow-1);
}
.btn-primary:hover { background: var(--accent-2); color: #fff; }
.btn-ghost {
  background: var(--bg);
  color: var(--ink);
  border-color: var(--rule-2);
}
.btn-ghost:hover { background: var(--bg-soft); border-color: var(--ink); }
.btn:active { transform: translateY(1px); }

/* ============ Abstract ============ */

.abstract {
  padding: 2.5rem 0 1.5rem;
  border-bottom: 1px solid var(--rule);
}
.abstract h2 {
  font-size: 0.78rem;
  font-family: var(--mono);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 0.9rem;
  font-weight: 500;
}
.abstract p {
  font-size: 1.02rem;
  line-height: 1.7;
  color: var(--ink-2);
  margin: 0 0 1rem;
  text-align: justify;
  hyphens: auto;
}

/* ============ Logo ============ */

.logo-block {
  text-align: center;
  padding: 2.25rem 0 1.5rem;
  border-bottom: 1px solid var(--rule);
}
.logo-block img {
  max-width: 100%;
  height: auto;
}
.logo-block .teaser-img {
  width: 100%;
  max-width: 100%;
  border-radius: 6px;
  box-shadow: 0 1px 0 rgba(0,0,0,0.04), 0 18px 38px -22px rgba(0,0,0,0.18);
}
.logo-caption {
  font-family: var(--mono);
  font-size: 0.74rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 0.6rem;
}

/* ============ Intro + stats ============ */

.intro {
  padding: 2.25rem 0 0.5rem;
}
.intro p {
  font-size: 1rem;
  color: var(--ink-2);
  margin: 0 0 1rem;
}

.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.9rem;
  padding: 1.25rem 0 2.25rem;
  border-bottom: 1px solid var(--rule);
}
@media (max-width: 720px) {
  .stats { grid-template-columns: repeat(2, 1fr); }
}
.stat {
  border: 1px solid var(--rule);
  padding: 1.1rem 1.1rem 1rem;
  background: var(--bg);
  border-radius: 4px;
}
.stat .num {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 1.65rem;
  letter-spacing: -0.02em;
  color: var(--accent);
  line-height: 1.05;
}
.stat .lbl {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 0.45rem;
}

/* ============ Tab nav ============ */

.tab-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--bg);
  border-bottom: 1px solid var(--rule);
  margin: 0;
  padding: 0;
}
.tab-nav .tab-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  padding: 0;
  margin: 0;
  list-style: none;
}
.tab-nav a {
  display: inline-block;
  padding: 1rem 1.1rem;
  font-family: var(--sans);
  font-weight: 500;
  font-size: 0.92rem;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: color 120ms ease, border-color 120ms ease;
}
.tab-nav a:hover { color: var(--ink); }
.tab-nav a.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ============ Tab panels ============ */

.tab-panel {
  display: none;
  padding: 2.5rem 0 3rem;
  border-bottom: 1px solid var(--rule);
}
/* Overview wraps prose sections that already have their own padding/borders. */
#overview.tab-panel { padding: 0; border-bottom: 0; }
#overview > section.intro { border-bottom: 1px solid var(--rule); }
.tab-panel.active { display: block; animation: fadeIn 220ms ease both; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }

.panel-head {
  margin-bottom: 1.5rem;
}
.panel-head h2 {
  margin: 0 0 0.5rem;
  font-size: clamp(1.4rem, 2.4vw, 1.85rem);
  font-weight: 700;
  letter-spacing: -0.015em;
  color: var(--ink);
}
.panel-head p {
  margin: 0;
  color: var(--muted);
  font-size: 0.96rem;
}

/* ============ Selectors ============ */

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  align-items: end;
  padding: 1rem 0 1.5rem;
}
.field {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}
.field label {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}
.field select {
  appearance: none;
  -webkit-appearance: none;
  background:
    linear-gradient(45deg, transparent 50%, var(--ink) 50%) calc(100% - 18px) 50% no-repeat,
    linear-gradient(135deg, var(--ink) 50%, transparent 50%) calc(100% - 13px) 50% no-repeat,
    var(--bg);
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
  border: 1px solid var(--rule-2);
  border-radius: 3px;
  padding: 0.5rem 2.1rem 0.5rem 0.7rem;
  font-family: var(--sans);
  font-size: 0.92rem;
  color: var(--ink);
  min-width: 14rem;
  cursor: pointer;
  transition: border-color 120ms ease;
}
.field select:focus {
  outline: 2px solid var(--accent-soft);
  outline-offset: 2px;
  border-color: var(--accent);
}
.field select:hover { border-color: var(--ink-2); }

/* ============ Video card ============ */

.viewer {
  display: grid;
  grid-template-columns: 1.25fr 1fr;
  gap: 2rem;
  align-items: start;
}
@media (max-width: 880px) {
  .viewer { grid-template-columns: 1fr; }
}
.viewer video {
  width: 100%;
  display: block;
  background: #0d0e10;
  border-radius: 4px;
  box-shadow: var(--shadow-1);
}
.viewer .meta {
  font-size: 0.95rem;
  color: var(--ink-2);
}
.viewer .meta h3 {
  margin: 0 0 0.5rem;
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: -0.005em;
  color: var(--ink);
}
.viewer .meta dl {
  margin: 1rem 0 0;
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 0.4rem 1rem;
  font-size: 0.9rem;
}
.viewer .meta dt {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  padding-top: 0.05rem;
}
.viewer .meta dd { margin: 0; color: var(--ink); }
.viewer .meta blockquote {
  margin: 0.85rem 0 0;
  padding: 0.6rem 0.9rem;
  background: var(--accent-soft);
  border-left: 3px solid var(--accent);
  font-style: italic;
  color: var(--ink);
  font-size: 0.92rem;
}
.video-fallback {
  width: 100%;
  aspect-ratio: 4 / 3;
  background: var(--bg-soft);
  border: 1px dashed var(--rule-2);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  text-align: center;
  padding: 1rem;
}

/* ============ Rollouts grid ============ */

.rollouts-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}
@media (max-width: 920px) { .rollouts-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .rollouts-grid { grid-template-columns: 1fr; } }
.rollout {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.rollout video {
  width: 100%;
  background: #0d0e10;
  border-radius: 4px;
  box-shadow: var(--shadow-1);
}
.rollout figcaption {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--ink-2);
}
.rollout figcaption .policy {
  font-family: var(--mono);
  font-size: 0.74rem;
  letter-spacing: 0.12em;
  color: var(--accent);
}
.rollout figcaption .task { color: var(--ink); }
.rollout figcaption .scene {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--muted);
}

/* ============ Tables (booktabs) ============ */

.table-wrap {
  overflow-x: auto;
  margin: 1rem 0 1.75rem;
}
.table-wrap h3 {
  font-size: 0.78rem;
  font-family: var(--mono);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 0.6rem;
  font-weight: 500;
}
table.booktabs {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
  font-variant-numeric: tabular-nums;
}
table.booktabs caption {
  text-align: left;
  caption-side: top;
  font-size: 0.92rem;
  color: var(--ink-2);
  margin-bottom: 0.5rem;
}
table.booktabs thead tr:first-child th { border-top: 2px solid var(--ink); }
table.booktabs thead tr:last-child  th { border-bottom: 1px solid var(--ink); }
table.booktabs tbody tr:last-child  td { border-bottom: 2px solid var(--ink); }
table.booktabs th,
table.booktabs td {
  padding: 0.55rem 0.7rem 0.55rem 0;
  text-align: left;
  border: none;
}
table.booktabs th {
  font-weight: 600;
  font-size: 0.82rem;
  text-transform: none;
  color: var(--ink);
}
table.booktabs th.num,
table.booktabs td.num {
  text-align: right;
  font-family: var(--mono);
  font-feature-settings: "tnum";
}
table.booktabs tbody tr:hover td { background: var(--accent-soft); }
table.booktabs td .delta-down { color: var(--warn); font-size: 0.78em; margin-left: 0.2em; }
table.booktabs td .delta-up   { color: #1d8050; font-size: 0.78em; margin-left: 0.2em; }
table.booktabs td .best { font-weight: 700; }

.table-note {
  font-size: 0.82rem;
  color: var(--muted);
  margin: 0 0 1rem;
  max-width: 80ch;
}

/* ============ Code / pre ============ */

code {
  font-family: var(--mono);
  font-size: 0.88em;
  background: var(--bg-soft);
  padding: 0.1em 0.35em;
  border-radius: 3px;
  color: var(--ink);
}
pre {
  background: #0d0f12;
  color: #e7eaee;
  padding: 1rem 1.15rem;
  border-radius: 4px;
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 0.85rem;
  line-height: 1.55;
  margin: 1rem 0;
  box-shadow: var(--shadow-1);
}
pre code { background: transparent; padding: 0; color: inherit; font-size: 1em; }

/* ============ Links ============ */

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid var(--accent-soft);
  transition: border-color 120ms ease, color 120ms ease;
}
a:hover { color: var(--accent-2); border-bottom-color: var(--accent); }

/* ============ Footer ============ */

footer {
  padding: 2.5rem 0 3.25rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--muted);
  border-top: 2px solid var(--ink);
  margin-top: 1rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}
footer a { color: var(--ink); border-bottom-color: var(--rule-2); }

/* ============ Misc ============ */

::selection { background: var(--accent); color: var(--bg); }
small { color: var(--muted); font-family: var(--mono); font-size: 0.78rem; }
hr { border: 0; border-top: 1px solid var(--rule); margin: 2rem 0; }

/* Inline pill chips for "atomic / compositional" tags */
.chip {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  padding: 0.18rem 0.5rem;
  border-radius: 999px;
  border: 1px solid var(--rule-2);
  color: var(--muted);
  vertical-align: middle;
}
.chip.atomic        { color: var(--accent); border-color: var(--accent-soft); background: var(--accent-soft); }
.chip.compositional { color: #6c4a1f;     border-color: #efe4cd;            background: #f8efd9;            }