/* BEX — design tokens. Cool, technical, dual-theme. */

:root {
  /* Type */
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, monospace;
  --font-sans: "Inter Tight", "Inter", system-ui, -apple-system, sans-serif;

  /* Spacing scale (8pt-ish) */
  --s-1: 4px;  --s-2: 8px;  --s-3: 12px; --s-4: 16px;
  --s-5: 24px; --s-6: 32px; --s-7: 48px; --s-8: 64px;
  --s-9: 96px; --s-10: 128px; --s-11: 160px;

  /* Radius */
  --r-1: 4px; --r-2: 8px; --r-3: 14px; --r-4: 20px; --r-pill: 999px;

  /* Motion */
  --ease-out: cubic-bezier(.22,.61,.36,1);
  --ease-in-out: cubic-bezier(.65,0,.35,1);
  --dur-fast: 180ms;
  --dur-med: 320ms;
  --dur-slow: 600ms;

  /* Layout */
  --page-max: 1440px;
  --gutter: clamp(20px, 4vw, 56px);
}

/* DARK — default */
:root, :root[data-theme="dark"] {
  --bg: oklch(0.16 0.012 240);
  --bg-elev: oklch(0.195 0.014 240);
  --surface: oklch(0.225 0.015 240);
  --surface-2: oklch(0.26 0.016 240);
  --line: oklch(0.34 0.018 240 / 0.55);
  --line-soft: oklch(0.34 0.018 240 / 0.22);
  --text: oklch(0.97 0.005 240);
  --text-dim: oklch(0.75 0.012 240);
  --text-mute: oklch(0.55 0.014 240);
  --accent: #2563EB;
  --accent-2: #60A5FA;
  --accent-dim: rgba(37,99,235,0.55);
  --accent-glow: rgba(37,99,235,0.35);
  --warn: oklch(0.82 0.14 75);
  --bad: oklch(0.7 0.17 25);

  --grad-hero: radial-gradient(ellipse 60% 45% at 25% 20%, rgba(37,99,235,0.35), transparent 60%),
               radial-gradient(ellipse 50% 35% at 80% 80%, rgba(96,165,250,0.22), transparent 60%);

  --grid-line: oklch(0.34 0.018 240 / 0.18);
  --noise-op: 0.06;
  color-scheme: dark;
}

:root[data-theme="light"] {
  --bg: oklch(0.985 0.004 240);
  --bg-elev: oklch(0.965 0.006 240);
  --surface: oklch(0.94 0.008 240);
  --surface-2: oklch(0.91 0.01 240);
  --line: oklch(0.55 0.014 240 / 0.35);
  --line-soft: oklch(0.55 0.014 240 / 0.15);
  --text: oklch(0.17 0.015 240);
  --text-dim: oklch(0.38 0.014 240);
  --text-mute: oklch(0.55 0.012 240);
  --accent: #2563EB;
  --accent-2: #7AA5FF;
  --accent-dim: rgba(37,99,235,0.45);
  --accent-glow: rgba(37,99,235,0.18);
  --warn: oklch(0.62 0.16 60);
  --bad: oklch(0.58 0.2 25);

  --grid-line: oklch(0.5 0.014 240 / 0.12);
  --noise-op: 0.035;
  color-scheme: light;
}

/* Accent tweaks */
:root {
  --fv-green:  oklch(0.7 0.17 150);
  --fv-yellow: oklch(0.82 0.14 85);
  --fv-red:    oklch(0.72 0.17 25);
}
:root[data-theme="light"] {
  --fv-green:  oklch(0.55 0.17 150);
  --fv-yellow: oklch(0.62 0.16 75);
  --fv-red:    oklch(0.55 0.2 25);
}
:root[data-accent="cyan"]   { --accent: #2563EB; --accent-2: #60A5FA; --accent-dim: rgba(37,99,235,0.55); --accent-glow: rgba(37,99,235,0.35); }
:root[data-accent="lime"]   { --accent: oklch(0.86 0.18 130); --accent-dim: oklch(0.86 0.18 130 / 0.55); --accent-glow: oklch(0.86 0.18 130 / 0.35); }
:root[data-accent="amber"]  { --accent: oklch(0.82 0.16 75);  --accent-dim: oklch(0.82 0.16 75 / 0.55);  --accent-glow: oklch(0.82 0.16 75 / 0.35); }
:root[data-accent="magenta"]{ --accent: oklch(0.72 0.2 330);  --accent-dim: oklch(0.72 0.2 330 / 0.55);  --accent-glow: oklch(0.72 0.2 330 / 0.35); }

:root[data-theme="light"][data-accent="cyan"]    { --accent: #2563EB; --accent-2: #7AA5FF; --accent-dim: rgba(37,99,235,0.45); --accent-glow: rgba(37,99,235,0.18); }
:root[data-theme="light"][data-accent="lime"]    { --accent: oklch(0.55 0.17 135); --accent-dim: oklch(0.55 0.17 135 / 0.5); --accent-glow: oklch(0.55 0.17 135 / 0.2); }
:root[data-theme="light"][data-accent="amber"]   { --accent: oklch(0.58 0.16 60);  --accent-dim: oklch(0.58 0.16 60 / 0.5);  --accent-glow: oklch(0.58 0.16 60 / 0.2); }
:root[data-theme="light"][data-accent="magenta"] { --accent: oklch(0.5 0.22 330);  --accent-dim: oklch(0.5 0.22 330 / 0.5);  --accent-glow: oklch(0.5 0.22 330 / 0.2); }

/* Global */
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-feature-settings: "ss01", "cv11";
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background var(--dur-med) var(--ease-out), color var(--dur-med) var(--ease-out);
  overflow-x: hidden;
}
* { transition: border-color var(--dur-med) var(--ease-out), background-color var(--dur-med) var(--ease-out); }

::selection { background: var(--accent-glow); color: var(--text); }

a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }

.mono { font-family: var(--font-mono); font-feature-settings: "zero"; }
.sans { font-family: var(--font-sans); }

.container {
  width: 100%;
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-mute);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.eyebrow::before {
  content: "";
  display: inline-block;
  width: 6px; height: 6px;
  background: var(--accent);
  border-radius: 50%;
  box-shadow: 0 0 12px var(--accent-glow);
}

.h1 { font-size: clamp(44px, 7vw, 96px); line-height: 0.98; letter-spacing: -0.03em; font-weight: 500; }
.h2 { font-size: clamp(32px, 4.4vw, 64px); line-height: 1.02; letter-spacing: -0.025em; font-weight: 500; }
.h3 { font-size: clamp(22px, 2.2vw, 30px); line-height: 1.15; letter-spacing: -0.015em; font-weight: 500; }
.lead { font-size: clamp(16px, 1.2vw, 19px); line-height: 1.55; color: var(--text-dim); max-width: 62ch; }
.mono-label { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.08em; color: var(--text-mute); text-transform: uppercase; }

/* Button */
.btn {
  --bg-btn: var(--accent);
  --fg-btn: #fff;
  display: inline-flex; align-items: center; gap: 10px;
  height: 48px; padding: 0 20px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2, var(--accent)));
  color: var(--fg-btn);
  border-radius: var(--r-pill);
  font-family: var(--font-mono); font-size: 13px;
  letter-spacing: 0.04em; text-transform: uppercase;
  position: relative; overflow: hidden;
  transition: transform var(--dur-fast) var(--ease-out), box-shadow var(--dur-med) var(--ease-out);
  box-shadow: 0 0 0 1px var(--accent-dim), 0 10px 30px -10px var(--accent-glow);
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 0 0 1px var(--accent), 0 20px 40px -12px var(--accent-glow), 0 0 0 1px color-mix(in oklch, var(--accent-2, var(--accent)) 50%, transparent); }
.btn .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--fg-btn); }
.btn.ghost {
  background: transparent;
  color: var(--text);
  box-shadow: inset 0 0 0 1px var(--line);
}
.btn.ghost:hover { box-shadow: inset 0 0 0 1px var(--text); }

/* Tag / chip */
.chip {
  display: inline-flex; align-items: center; gap: 6px;
  height: 24px; padding: 0 10px;
  border-radius: var(--r-pill);
  border: 1px solid var(--line-soft);
  background: var(--surface);
  font-family: var(--font-mono); font-size: 11px; color: var(--text-dim);
  letter-spacing: 0.04em;
}

/* Grid background helper */
.grid-bg {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 40%, #000 30%, transparent 80%);
  pointer-events: none;
}

/* Section base */
section {
  position: relative;
  padding: var(--s-10) 0;
  border-top: 1px solid var(--line-soft);
}
section:first-of-type { border-top: 0; }

.section-head {
  display: block;
  margin-bottom: var(--s-8);
  max-width: 900px;
}
.section-head .h2 { margin: 0; }
@media (max-width: 720px) {
  .section-head { margin-bottom: var(--s-6); }
}
.section-index {
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: var(--s-4);
  padding-bottom: var(--s-3);
  border-bottom: 1px solid var(--line-soft);
}
.section-index::before {
  content: "";
  width: 28px;
  height: 1px;
  background: var(--accent);
  flex-shrink: 0;
}

/* Reveal */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity 700ms var(--ease-out), transform 700ms var(--ease-out); }
.reveal.in { opacity: 1; transform: none; }

/* Utility */
.sr-only { position:absolute; width:1px; height:1px; padding:0; margin:-1px; overflow:hidden; clip:rect(0 0 0 0); white-space:nowrap; border:0; }