* { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

:root {
  color-scheme: dark;
}
:root[data-theme="light"] {
  color-scheme: light;
}
@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    color-scheme: light;
  }
}
:root.dark,
:root[data-theme="dark"] {
  color-scheme: dark;
}

body {
  margin: 0;
  background-color: var(--bg);
  color: var(--ink);
  font: 14px/1.55 var(--sans);
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

/* Background Linear Grid Pattern */
.grid-background {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background-image: 
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 220px 220px;
  background-position: center top;
  opacity: 0.65;
}

.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--s-6);
  position: relative;
  z-index: 1;
}

@media (max-width: 719px) {
  .container {
    padding: 0 var(--s-4);
  }
}

.num, .mono, .fig, .stat-n, td.num, th.num {
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1;
}

a {
  color: var(--signal);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease);
}
a:hover {
  color: var(--math-blue);
  text-decoration: underline;
  text-underline-offset: 2px;
}

:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 2px;
  border-radius: var(--r-sm);
}

::selection {
  background: var(--signal);
  color: var(--bg);
}

/* Typography Hierarchy — Fanout Grotesk */
h1 {
  font: 600 clamp(28px, 4vw, 42px)/1.08 var(--sans);
  letter-spacing: -1.5px;
  margin: 0;
  color: var(--ink);
}

.hero-title {
  font-family: var(--sans);
  font-size: clamp(32px, 5.5vw, 64px);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -2px;
  color: var(--ink);
  margin: var(--s-4) 0;
}

.section-title {
  font-family: var(--sans);
  font-size: clamp(22px, 3.5vw, 32px);
  font-weight: 650;
  line-height: 1.2;
  letter-spacing: -1px;
  color: var(--ink);
}

h2 {
  font: 650 11px/1.2 var(--sans);
  text-transform: uppercase;
  letter-spacing: .13em;
  color: var(--muted);
  margin: var(--s-10) 0 var(--s-3);
  display: flex;
  align-items: center;
  gap: var(--s-3);
}
h2::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--line-soft);
}

h3, .card-title {
  font: 600 22px/1.3 var(--sans);
  letter-spacing: -0.5px;
  margin: 0 0 var(--s-2);
  color: var(--ink);
}

.lede {
  color: var(--ink-dim);
  font-size: 15px;
  line-height: 1.6;
  max-width: 72ch;
  margin: 0 0 var(--s-6);
}

.sub {
  color: var(--muted);
  font-size: 12.5px;
  line-height: 1.5;
  max-width: 76ch;
  margin: 0 0 var(--s-5);
}

/* Monospace & Micro Typography */
.mono-tag {
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.72px;
  text-transform: uppercase;
  color: var(--muted);
}

.mono-sub {
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.5px;
  color: var(--faint);
}

.mono-text {
  font-family: var(--mono);
  font-size: 13px;
  line-height: 20px;
}

.text-muted { color: var(--muted); }
.text-faint { color: var(--faint); }
.text-signal { color: var(--signal); }
.text-math { color: var(--math-blue); }

.skip-link {
  position: absolute;
  left: -9999px;
  background: var(--signal);
  color: var(--bg);
  padding: var(--s-2) var(--s-4);
  border-radius: var(--r-button);
  z-index: 200;
  font-weight: 600;
}
.skip-link:focus {
  left: var(--s-4);
  top: var(--s-2);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important;
    transition-duration: .01ms !important;
    scroll-behavior: auto !important;
  }
}