/* ==========================================================================
   CRYSTAL DRIFT — static landing + game
   Design direction: retro-futuristic astro-editorial, deep-space navy,
   amber signal + teal crystal accents. No glassmorphism, no card-soup.
   ========================================================================== */

:root {
  /* Deep-space navy, tinted toward violet-blue */
  --bg:      oklch(0.21 0.035 258);
  --bg-2:    oklch(0.25 0.04 258);
  --bg-3:    oklch(0.3 0.045 258);
  --surface: oklch(0.27 0.035 258);
  --line:    oklch(0.42 0.05 258 / 0.55);

  --ink:     oklch(0.94 0.012 258);
  --ink-2:   oklch(0.78 0.02 258);
  --ink-3:   oklch(0.6 0.02 258);

  --amber:   oklch(0.8 0.135 75);
  --amber-d: oklch(0.62 0.13 75);
  --teal:    oklch(0.78 0.11 190);
  --violet:  oklch(0.68 0.13 285);

  --font-display: "Space Grotesk", "Avenir Next", "Segoe UI", system-ui, sans-serif;
  --font-body: "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4.5rem;
  --space-9: 6.5rem;

  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

body::before {
  /* faint astro-noise / star wash */
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background:
    radial-gradient(1px 1px at 12% 22%, oklch(1 0 0 / 0.5) 0, transparent 60%),
    radial-gradient(1px 1px at 78% 12%, oklch(1 0 0 / 0.4) 0, transparent 60%),
    radial-gradient(2px 2px at 33% 64%, oklch(0.8 0.11 190 / 0.5) 0, transparent 70%),
    radial-gradient(2px 2px at 88% 72%, oklch(0.8 0.135 75 / 0.4) 0, transparent 70%),
    radial-gradient(1px 1px at 55% 42%, oklch(1 0 0 / 0.35) 0, transparent 60%),
    radial-gradient(1px 1px at 8% 88%, oklch(1 0 0 / 0.45) 0, transparent 60%),
    radial-gradient(1px 1px at 66% 90%, oklch(1 0 0 / 0.3) 0, transparent 60%);
}

img, canvas, video { max-width: 100%; display: block; }
a { color: var(--teal); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--amber); }

.container {
  width: min(1120px, 92vw);
  margin-inline: auto;
  position: relative;
  z-index: 1;
}

/* ---------- header / nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in oklch, var(--bg) 78%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid transparent;
}

.site-header.scrolled { border-bottom-color: var(--line); }

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: var(--space-4);
}

.brand {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.brand .tag { color: var(--amber); font-weight: 500; }

.nav-links { display: flex; gap: var(--space-5); align-items: center; list-style: none; margin: 0; padding: 0; }
.nav-links a { color: var(--ink-2); text-decoration: none; font-size: 0.95rem; font-weight: 500; }
.nav-links a:hover { color: var(--amber); }

.btn { display:inline-block; font-family: var(--font-display); font-weight: 600; text-transform: uppercase; letter-spacing: 0.08em; font-size: 0.85rem; padding: 0.7rem 1.3rem; color: var(--bg); background: var(--amber); border-radius: 999px; text-decoration: none; transition: transform 0.18s var(--ease-out-expo), background 0.18s; }
.btn:hover { transform: translateY(-2px); background: color-mix(in oklch, var(--amber) 88%, white); color: var(--bg); }
.btn.btn-ghost { background: transparent; color: var(--teal); border: 1px solid color-mix(in oklch, var(--teal) 55%, transparent); }
.btn.btn-ghost:hover { background: color-mix(in oklch, var(--teal) 12%, transparent); }

/* ---------- hero ---------- */
.hero {
  padding: clamp(4rem, 10vw, 8rem) 0 var(--space-8);
  position: relative;
}
.eyebrow {
  font-family: var(--font-display);
  text-transform: uppercase;
  letter-spacing: 0.28em;
  font-size: 0.78rem;
  color: var(--teal);
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}
.eyebrow::before { content: ""; width: 2.2rem; height: 1px; background: currentColor; }

.hero h1 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2.6rem, 7vw, 5.2rem);
  line-height: 0.98;
  letter-spacing: -0.02em;
  margin: var(--space-5) 0 var(--space-4);
  max-width: 15ch;
  text-wrap: balance;
}
.hero h1 .hl { color: var(--amber); }
.hero .lede {
  font-size: clamp(1.05rem, 2vw, 1.3rem);
  color: var(--ink-2);
  max-width: 52ch;
  margin: 0 0 var(--space-6);
  text-wrap: pretty;
}
.hero-meta { display: flex; gap: var(--space-6); flex-wrap: wrap; margin-bottom: var(--space-6); }
.hero-meta .stat b { display: block; font-family: var(--font-display); font-size: 1.5rem; color: var(--amber); }
.hero-meta .stat span { color: var(--ink-3); font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.12em; }

.hero-cta { display: flex; gap: var(--space-4); flex-wrap: wrap; }

.hero-visual {
  margin-top: var(--space-7);
  border-radius: 1.2rem;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--bg-2);
  box-shadow: 0 30px 60px -30px oklch(0 0 0 / 0.8);
  position: relative;
}
.hero-visual canvas, .hero-visual iframe { width: 100%; aspect-ratio: 16 / 7; display: block; }
.caption {
  padding: var(--space-3) var(--space-5);
  color: var(--ink-3);
  font-size: 0.82rem;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  gap: var(--space-4);
}

/* ---------- sections ---------- */
section.block { padding-block: var(--space-8); }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: var(--space-5); margin-bottom: var(--space-6); }
.section-head h2 {
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 4vw, 2.6rem);
  margin: var(--space-2) 0 0;
  letter-spacing: -0.01em;
}

/* fact strip (GEO-friendly, machine readable) */
.fact-panel {
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-left: 4px solid var(--amber);
  border-radius: 0.8rem;
  padding: var(--space-5) var(--space-6);
  margin-block: var(--space-6);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-5);
}
.fact-panel dt { font-family: var(--font-display); text-transform: uppercase; letter-spacing: 0.16em; font-size: 0.72rem; color: var(--amber-d); }
.fact-panel dd { margin: var(--space-1) 0 0; font-size: 0.98rem; color: var(--ink-2); }

/* feature grid — deliberately asymmetric, no cards */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--space-5);
}
.feature {
  grid-column: span 4;
  padding-block: var(--space-4);
  border-top: 1px solid var(--line);
}
.feature:nth-child(2) { grid-column: span 5; }
.feature:nth-child(3) { grid-column: span 3; }
.feature .idx { font-family: var(--font-display); color: var(--teal); font-size: 0.85rem; letter-spacing: 0.2em; }
.feature h3 { font-family: var(--font-display); font-size: 1.25rem; margin: var(--space-2) 0 var(--space-1); }
.feature p { color: var(--ink-2); font-size: 0.95rem; margin: 0; }

/* how-to-play step list */
.steps { counter-reset: step; list-style: none; margin: 0; padding: 0; }
.steps li {
  counter-increment: step;
  display: grid;
  grid-template-columns: 3.2rem 1fr;
  gap: var(--space-4);
  padding-block: var(--space-4);
  border-top: 1px solid var(--line);
  align-items: start;
}
.steps li::before {
  content: "0" counter(step);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.3rem;
  color: var(--violet);
}
.steps h3 { margin: 0 0 var(--space-1); font-family: var(--font-display); font-size: 1.15rem; }
.steps p { margin: 0; color: var(--ink-2); max-width: 60ch; }

/* FAQ */
.faq { max-width: 820px; }
.faq details {
  border-top: 1px solid var(--line);
  padding-block: var(--space-4);
}
.faq details:last-of-type { border-bottom: 1px solid var(--line); }
.faq summary {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.1rem;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: var(--space-4);
  align-items: center;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--amber); font-size: 1.4rem; transition: transform 0.2s var(--ease-out-expo); }
.faq details[open] summary::after { transform: rotate(45deg); }
.faq .a { color: var(--ink-2); margin-top: var(--space-3); max-width: 70ch; padding-bottom: var(--space-2); }

/* footer */
.site-footer {
  border-top: 1px solid var(--line);
  margin-top: var(--space-8);
  padding-block: var(--space-7) var(--space-8);
  color: var(--ink-3);
  font-size: 0.9rem;
}
.site-footer .foot-grid { display: flex; justify-content: space-between; gap: var(--space-6); flex-wrap: wrap; }

/* hero art (CSS starfield + SVG ship) */
.hero-art {
  position: relative;
  aspect-ratio: 16 / 7;
  background:
    radial-gradient(1px 1px at 20% 30%, #fff 0, transparent 60%),
    radial-gradient(1px 1px at 70% 20%, #fff 0, transparent 60%),
    radial-gradient(1.5px 1.5px at 45% 60%, #7dd3fc 0, transparent 70%),
    radial-gradient(1px 1px at 85% 70%, #ffe7b3 0, transparent 60%),
    radial-gradient(1px 1px at 10% 75%, #fff 0, transparent 60%),
    radial-gradient(1.5px 1.5px at 55% 15%, #a78bfa 0, transparent 70%),
    radial-gradient(1px 1px at 92% 35%, #fff 0, transparent 60%),
    radial-gradient(ellipse 60% 45% at 78% 80%, oklch(0.72 0.12 55 / 0.6), transparent 70%),
    linear-gradient(180deg, oklch(0.16 0.04 260) 0%, oklch(0.24 0.045 258) 100%);
  overflow: hidden;
}
.hero-art .s1,.hero-art .s2,.hero-art .s3,.hero-art .s4,.hero-art .s5,.hero-art .s6 {
  position: absolute; border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, #ffe7b3, transparent 70%);
  opacity: 0.85; animation: twinkle 3.2s ease-in-out infinite;
}
.hero-art .s1 { width: 5px; height: 5px; left: 14%; top: 22%; }
.hero-art .s2 { width: 3px; height: 3px; left: 34%; top: 60%; animation-delay: 0.6s; }
.hero-art .s3 { width: 4px; height: 4px; left: 62%; top: 30%; animation-delay: 1.1s; }
.hero-art .s4 { width: 3px; height: 3px; left: 80%; top: 68%; animation-delay: 1.6s; }
.hero-art .s5 { width: 5px; height: 5px; left: 92%; top: 24%; animation-delay: 0.3s; }
.hero-art .s6 { width: 3px; height: 3px; left: 8%; top: 58%; animation-delay: 0.9s; }
@keyframes twinkle { 0%,100% { opacity: 0.25; transform: scale(0.85); } 50% { opacity: 1; transform: scale(1.15); } }
.hero-svg { position: absolute; inset: 0; margin: auto; width: 78%; height: 78%; animation: drift-in 1.1s var(--ease-out-expo) both; }
@keyframes drift-in { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: translateY(0); } }

/* ---------- game page ---------- */
.game-shell { position: fixed; inset: 0; background: #060a12; overflow: hidden; }
#game-canvas { width: 100%; height: 100%; display: block; touch-action: none; }
.hud {
  position: absolute;
  top: var(--space-5);
  left: var(--space-5);
  right: var(--space-5);
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  pointer-events: none;
  z-index: 5;
  font-family: var(--font-display);
}
.hud .score b { font-size: 2rem; color: var(--amber); display: block; line-height: 1; letter-spacing: 0.04em; }
.hud .score span { color: var(--ink-3); text-transform: uppercase; letter-spacing: 0.2em; font-size: 0.7rem; }
.hud .lives { display: flex; gap: var(--space-1); }
.hud .lives i { width: 14px; height: 14px; border-radius: 50%; background: var(--teal); }
.hud .lives i.off { background: color-mix(in oklch, var(--teal) 20%, transparent); }
.hud .back { pointer-events: auto; color: var(--ink-2); text-decoration: none; font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.12em; }
.hud .back:hover { color: var(--amber); }

.overlay {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  text-align: center;
  background: oklch(0.12 0.03 258 / 0.72);
  backdrop-filter: blur(4px);
  z-index: 10;
}
.overlay[hidden] { display: none; }
.overlay .panel { max-width: 520px; padding: var(--space-6); }
.overlay h1, .overlay h2 { font-family: var(--font-display); font-weight: 700; margin: 0 0 var(--space-3); letter-spacing: -0.01em; }
.overlay h1 { font-size: clamp(2rem, 6vw, 3.4rem); }
.overlay p { color: var(--ink-2); margin: 0 0 var(--space-5); }
.overlay .kbd { font-family: var(--font-display); background: var(--bg-3); padding: 0.15rem 0.5rem; border-radius: 0.4rem; border: 1px solid var(--line); }

.controls-hint {
  position: absolute;
  bottom: var(--space-5);
  left: 50%;
  transform: translateX(-50%);
  color: var(--ink-3);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  z-index: 5;
  pointer-events: none;
  opacity: 0.7;
}

/* ---------- responsive ---------- */
@media (max-width: 860px) {
  .nav-links { display: none; }
  .feature, .feature:nth-child(2), .feature:nth-child(3) { grid-column: span 6; }
  .hero-cta { flex-direction: column; align-items: stretch; }
  .hero-cta .btn { text-align: center; }
}
@media (max-width: 560px) {
  .feature, .feature:nth-child(2), .feature:nth-child(3) { grid-column: span 12; }
  .hero-meta { gap: var(--space-4); }
}

/* ---------- motion ---------- */
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}

.skip-link {
  position: absolute; left: -999px; top: 0; z-index: 100;
  background: var(--amber); color: var(--bg); padding: 0.6rem 1rem; border-radius: 0 0 0.5rem 0;
}
.skip-link:focus { left: 0; }