/* ============================================================
   PRo3D — Planetary Robotics 3D Viewer
   ============================================================ */

:root {
  --bg:            #0a0c11;
  --bg-alt:        #0e1119;
  --surface:       #151a24;
  --surface-2:     #1b2130;
  --border:        #262d3d;
  --border-soft:   #1e2431;

  --text:          #e9edf3;
  --text-muted:    #98a2b3;
  --text-dim:      #6b7688;

  --accent:        #e2724f;   /* mars rust */
  --accent-soft:   #f0916f;
  --accent-dim:    rgba(226, 114, 79, 0.14);
  --accent-line:   rgba(226, 114, 79, 0.35);

  --radius:        14px;
  --radius-lg:     20px;
  --wrap:          1160px;
  --wrap-narrow:   760px;

  --ease:          cubic-bezier(0.22, 1, 0.36, 1);

  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto,
          "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
          "Liberation Mono", monospace;
}

/* ── Reset ─────────────────────────────────────────────── */

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 90px; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

img { max-width: 100%; height: auto; display: block; }

a { color: var(--accent-soft); text-decoration: none; }
a:hover { color: var(--accent); }

h1, h2, h3 { line-height: 1.15; letter-spacing: -0.022em; margin: 0; text-wrap: balance; }

p { margin: 0 0 1.1em; }
p:last-child { margin-bottom: 0; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.skip-link {
  position: absolute; left: -9999px;
  background: var(--accent); color: #fff;
  padding: 12px 20px; z-index: 200; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; top: 0; color: #fff; }

/* ── Layout ────────────────────────────────────────────── */

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: 24px;
}
.wrap.narrow { max-width: var(--wrap-narrow); }
.center { text-align: center; }

.section { padding: 104px 0; position: relative; }
.section-alt { background: var(--bg-alt); border-block: 1px solid var(--border-soft); }

.section-head { margin-bottom: 64px; max-width: 720px; }
.center .section-head { margin-inline: auto; }

.section-title {
  font-size: clamp(1.85rem, 3.6vw, 2.6rem);
  font-weight: 640;
  margin-bottom: 0.5em;
}
.section-sub { color: var(--text-muted); margin: 0; }

.eyebrow {
  font-size: 0.775rem;
  font-weight: 650;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 14px;
}

.prose-lg { font-size: 1.115rem; color: var(--text-muted); }
.prose-lg strong, .prose-lg b { color: var(--text); font-weight: 600; }
.muted { color: var(--text-muted); font-size: 0.95rem; }

/* ── Header ────────────────────────────────────────────── */

.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(10, 12, 17, 0.72);
  backdrop-filter: saturate(160%) blur(14px);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s, background 0.3s;
}
.site-header.is-stuck {
  border-bottom-color: var(--border-soft);
  background: rgba(10, 12, 17, 0.9);
}

.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 24px; height: 68px;
}

.brand { display: inline-flex; align-items: center; gap: 11px; color: var(--text); }
.brand:hover { color: var(--text); }
.brand-mark {
  width: 13px; height: 13px; border-radius: 50%;
  background: radial-gradient(circle at 32% 30%, var(--accent-soft), #8f3a20 72%);
  box-shadow: 0 0 0 4px var(--accent-dim);
}
.brand-name { font-weight: 700; letter-spacing: -0.02em; font-size: 1.12rem; }

.site-nav { display: flex; align-items: center; gap: 4px; }
.site-nav a {
  color: var(--text-muted);
  font-size: 0.925rem; font-weight: 500;
  padding: 8px 13px; border-radius: 8px;
  transition: color 0.18s, background 0.18s;
}
.site-nav a:hover { color: var(--text); background: var(--surface); }
.site-nav a.is-active { color: var(--text); }

.site-nav .nav-cta {
  margin-left: 10px;
  background: var(--accent);
  color: #180a06;
  font-weight: 620;
}
.site-nav .nav-cta:hover { background: var(--accent-soft); color: #180a06; }

.nav-toggle {
  display: none;
  background: none; border: 0; cursor: pointer;
  width: 42px; height: 42px; padding: 10px;
  flex-direction: column; justify-content: space-between;
}
.nav-toggle span {
  display: block; height: 2px; width: 100%;
  background: var(--text); border-radius: 2px;
  transition: transform 0.3s var(--ease), opacity 0.2s;
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(9px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-9px) rotate(-45deg); }

/* ── Buttons ───────────────────────────────────────────── */

.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 24px; border-radius: 10px;
  font-size: 0.95rem; font-weight: 600;
  border: 1px solid transparent;
  transition: transform 0.18s var(--ease), background 0.18s, border-color 0.18s;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn-sm { padding: 9px 17px; font-size: 0.875rem; }

.btn-primary { background: var(--accent); color: #180a06; }
.btn-primary:hover { background: var(--accent-soft); color: #180a06; }

.btn-ghost { border-color: var(--border); color: var(--text); background: var(--surface); }
.btn-ghost:hover { border-color: var(--accent-line); color: var(--text); }
.btn-ghost svg {
  width: 13px; height: 13px; fill: none;
  stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round;
  opacity: 0.6;
}

/* ── Hero ──────────────────────────────────────────────── */

.hero { position: relative; padding: 90px 0 104px; overflow: hidden; }

.hero-glow {
  position: absolute; inset: auto 0 auto 50%;
  top: -280px; transform: translateX(-50%);
  width: 1100px; height: 700px;
  background: radial-gradient(ellipse at center, rgba(226,114,79,0.16), transparent 62%);
  pointer-events: none; z-index: 0;
  filter: blur(20px);
}

.hero-grid {
  position: relative; z-index: 1;
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 64px; align-items: center;
}

.hero h1 {
  font-size: clamp(2.3rem, 4.4vw, 3.4rem);
  font-weight: 680;
  letter-spacing: -0.035em;
  margin-bottom: 24px;
  text-wrap: balance;
}

.lede {
  font-size: 1.16rem;
  color: var(--text-muted);
  max-width: 46ch;
  margin-bottom: 34px;
  text-wrap: pretty;
}

.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }

.hero-figure {
  margin: 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: 0 40px 80px -30px rgba(0,0,0,0.85),
              0 0 0 1px rgba(255,255,255,0.03) inset;
}
.hero-figure img { width: 100%; }

/* ── Features ──────────────────────────────────────────── */

.feature {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 72px;
  align-items: center;
  padding: 56px 0;
}
.feature + .feature { border-top: 1px solid var(--border-soft); }
.feature-reverse .feature-media { order: 2; }

.feature-media {
  margin: 0;
  position: relative;
  display: flex; align-items: center; justify-content: center;
  padding: 20px;
  border-radius: var(--radius-lg);
  background:
    radial-gradient(ellipse at 50% 45%, rgba(226,114,79,0.08), transparent 68%),
    linear-gradient(180deg, var(--surface), var(--bg-alt));
  border: 1px solid var(--border-soft);
}
.feature-media img {
  max-height: 400px;
  width: auto;
  filter: drop-shadow(0 24px 48px rgba(0,0,0,0.6));
}

.feature-index {
  display: block;
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--accent);
  letter-spacing: 0.1em;
  margin-bottom: 12px;
}
.feature-copy h3 {
  font-size: clamp(1.5rem, 2.6vw, 1.95rem);
  font-weight: 640;
  margin-bottom: 18px;
}
.feature-copy p { color: var(--text-muted); }

.chips { display: flex; flex-wrap: wrap; gap: 8px; list-style: none; padding: 0; margin: 24px 0 0; }
.chips li {
  font-size: 0.83rem; font-weight: 500;
  padding: 6px 13px; border-radius: 100px;
  background: var(--accent-dim);
  color: var(--accent-soft);
  border: 1px solid var(--accent-line);
}

.stats {
  display: flex; gap: 32px; flex-wrap: wrap;
  list-style: none; padding: 0; margin: 28px 0 0;
}
.stats li { display: flex; flex-direction: column; }
.stats b {
  font-size: 1.5rem; font-weight: 680; letter-spacing: -0.02em;
  color: var(--text); line-height: 1.2;
}
.stats span { font-size: 0.82rem; color: var(--text-dim); }

/* ── Steps ─────────────────────────────────────────────── */

.steps {
  list-style: none; padding: 0; margin: 0;
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}
.steps li {
  background: var(--surface);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 32px 28px;
  display: flex; flex-direction: column; align-items: flex-start;
}
.steps h3 { font-size: 1.16rem; font-weight: 620; margin-bottom: 10px; }
.steps p { color: var(--text-muted); font-size: 0.945rem; }

.step-num {
  display: grid; place-items: center;
  width: 34px; height: 34px; margin-bottom: 20px;
  border-radius: 50%;
  background: var(--accent-dim);
  border: 1px solid var(--accent-line);
  color: var(--accent-soft);
  font-size: 0.875rem; font-weight: 680;
}

.datasets { list-style: none; padding: 0; margin: 4px 0 0; width: 100%; }
.datasets li {
  display: block;
  padding: 9px 0;
  border-top: 1px solid var(--border-soft);
  font-size: 0.925rem;
}
.datasets li:first-child { border-top: 0; }
.datasets a { font-weight: 560; }
.datasets span { display: block; color: var(--text-dim); font-size: 0.8rem; line-height: 1.4; }
.datasets sup { font-size: 0.62rem; }
.datasets sup a { color: var(--text-dim); }
.datasets sup a:hover { color: var(--accent); }

.code {
  font-family: var(--mono);
  font-size: 0.83rem;
  background: var(--bg);
  border: 1px solid var(--border-soft);
  border-radius: 8px;
  padding: 12px 14px;
  margin: 6px 0 0;
  color: var(--text-muted);
  width: 100%;
  overflow-x: auto;
}

/* ── Callout + refs ────────────────────────────────────── */

.callout {
  margin-top: 40px;
  padding: 32px 36px;
  border-radius: var(--radius);
  background: linear-gradient(180deg, var(--surface-2), var(--surface));
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
}
.callout p { color: var(--text-muted); }
.contacts { display: flex; flex-wrap: wrap; gap: 10px 40px; font-size: 0.92rem; margin-top: 18px; }
.contacts > span { display: block; color: var(--text-dim); }
.contacts a { white-space: nowrap; }
.at { color: var(--text-dim); }

.refs {
  margin-top: 40px;
  padding-top: 26px;
  border-top: 1px solid var(--border-soft);
}
.refs p {
  font-size: 0.8rem;
  line-height: 1.6;
  color: var(--text-dim);
  margin-bottom: 14px;
}
.refs sup { color: var(--accent); font-weight: 700; margin-right: 3px; }
.refs:target, .refs p:target { color: var(--text-muted); }

/* ── Citation ──────────────────────────────────────────── */

.citation {
  margin: 0 0 1.6em;
  padding: 24px 28px;
  background: var(--surface);
  border: 1px solid var(--border-soft);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  font-size: 0.96rem;
  color: var(--text-muted);
}
.citation-quote { font-style: italic; }
.citation-quote a { font-style: normal; word-break: break-word; }

/* ── Tutorials ─────────────────────────────────────────── */

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(290px, 1fr));
  gap: 26px;
}
.video-card h3 { font-size: 1.06rem; font-weight: 600; margin: 18px 0 6px; }
.video-card p { color: var(--text-muted); font-size: 0.925rem; }

.video-embed {
  position: relative;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--border-soft);
  display: grid; place-items: center;
}
.video-embed iframe {
  position: absolute; inset: 0;
  width: 100%; height: 100%; border: 0;
}

.is-placeholder .video-embed {
  background-image:
    repeating-linear-gradient(-45deg,
      transparent 0 11px,
      rgba(255,255,255,0.018) 11px 22px);
}
.is-placeholder h3, .is-placeholder p { color: var(--text-dim); }

.play {
  width: 54px; height: 54px; border-radius: 50%;
  background: var(--accent-dim);
  border: 1px solid var(--accent-line);
  display: grid; place-items: center;
}
.play::after {
  content: "";
  border-style: solid;
  border-width: 8px 0 8px 13px;
  border-color: transparent transparent transparent var(--accent);
  margin-left: 3px;
}

/* ── Logo chips (dark-ink logos need a light plate) ────── */

.logo-chip {
  display: inline-grid; place-items: center;
  background: #fff;
  border-radius: 10px;
  padding: 14px 20px;
  transition: transform 0.2s var(--ease), box-shadow 0.2s;
  box-shadow: 0 8px 24px -12px rgba(0,0,0,0.7);
}
.logo-chip:hover { transform: translateY(-2px); box-shadow: 0 14px 32px -12px rgba(0,0,0,0.8); }
.logo-chip img { height: 34px; width: auto; }

.logo-chip-lg { margin: 8px 0 34px; padding: 20px 30px; }
.logo-chip-lg img { height: 42px; }

/* ── Footer ────────────────────────────────────────────── */

.site-footer {
  background: var(--bg-alt);
  border-top: 1px solid var(--border-soft);
  padding: 64px 0 40px;
}

.footer-top {
  display: flex; justify-content: space-between;
  align-items: flex-start; gap: 40px; flex-wrap: wrap;
  padding-bottom: 44px;
}
.footer-brand p { color: var(--text-dim); font-size: 0.9rem; margin: 4px 0 0; }

.footer-links { display: flex; gap: 26px; flex-wrap: wrap; }
.footer-links a { color: var(--text-muted); font-size: 0.925rem; }
.footer-links a:hover { color: var(--text); }

.partners {
  display: flex; align-items: center; gap: 20px; flex-wrap: wrap;
  padding: 36px 0;
  border-top: 1px solid var(--border-soft);
  border-bottom: 1px solid var(--border-soft);
}

.colophon {
  margin-top: 32px;
  font-size: 0.8rem;
  color: var(--text-dim);
}

/* ── Reveal animation ──────────────────────────────────── */

.reveal { opacity: 0; transform: translateY(18px); }
.reveal.is-visible {
  opacity: 1; transform: none;
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}

/* ── Responsive ────────────────────────────────────────── */

@media (max-width: 940px) {
  .hero-grid { grid-template-columns: 1fr; gap: 48px; }
  .hero-figure { order: -1; }
  .lede { max-width: none; }

  .feature { grid-template-columns: 1fr; gap: 36px; padding: 48px 0; }
  .feature-reverse .feature-media { order: 0; }
  .feature-media img { max-height: 320px; }

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

@media (max-width: 780px) {
  body { font-size: 16px; }
  .section { padding: 76px 0; }
  .section-head { margin-bottom: 44px; }

  .nav-toggle { display: flex; }

  .site-nav {
    position: absolute; top: 68px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 2px;
    padding: 14px 20px 22px;
    background: var(--bg-alt);
    border-bottom: 1px solid var(--border);
    transform-origin: top;
    display: none;
  }
  .site-nav.is-open { display: flex; }
  .site-nav a { padding: 12px 14px; font-size: 1rem; }
  .nav-cta { margin: 8px 0 0; justify-content: center; display: flex; }

  .callout { padding: 26px 22px; }
  .contacts { flex-direction: column; gap: 10px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}