/* Link the AI public site. Follows docs/DESIGN.md:
   dark hero and footer, white body sections, Signal Green accent, 2px radius, Inter. */
:root {
  --primary: #76b900;
  --primary-dark: #5a8d00;
  --ink: #000000;
  --body: #1a1a1a;
  --mute: #757575;
  --canvas: #ffffff;
  --soft: #f7f7f7;
  --dark: #000000;
  --elevated: #1a1a1a;
  --on-dark: #ffffff;
  --on-dark-mute: rgba(255, 255, 255, 0.7);
  --hairline: #cccccc;
  --hairline-strong: #5e5e5e;
  --link: #0046a4;
  --error: #e52020;
  --radius: 2px;
  --font: "Inter", Arial, Helvetica, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body { margin: 0; font: 400 16px/1.5 var(--font); color: var(--body); background: var(--canvas); }
a { color: var(--link); }
:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }
.wrap { width: min(1280px, 100% - 48px); margin: 0 auto; }

/* Nav */
.nav { position: sticky; top: 0; z-index: 10; background: var(--dark); color: var(--on-dark); box-shadow: 0 0 5px 0 rgba(0, 0, 0, 0.3); }
.nav .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; min-height: 64px; }
.brand { display: inline-flex; align-items: center; gap: 12px; color: var(--on-dark); text-decoration: none; font: 700 18px/1.25 var(--font); }
.brand img { height: 36px; width: auto; display: block; background: var(--canvas); padding: 3px 6px; border-radius: var(--radius); }
.nav ul { display: flex; align-items: center; gap: 24px; list-style: none; margin: 0; padding: 0; }
.nav ul a { color: var(--on-dark); text-decoration: none; font-weight: 700; padding: 8px 0; border-bottom: 2px solid transparent; }
.nav ul a:hover { color: var(--primary); }

/* Buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; padding: 11px 24px; background: var(--primary); color: #000; border: 2px solid var(--primary); border-radius: var(--radius); font: 700 16px/1.25 var(--font); text-decoration: none; cursor: pointer; }
.btn:hover { background: var(--primary-dark); border-color: var(--primary-dark); color: #000; }
.btn.outline { background: transparent; color: var(--on-dark); border-color: var(--on-dark); }
.btn.outline:hover { background: rgba(255, 255, 255, 0.12); border-color: var(--on-dark); color: var(--on-dark); }
.btn.lg { font-size: 18px; padding: 14px 28px; }
.nav .btn { min-height: 40px; padding: 8px 18px; font-size: 15px; color: #000; }
.nav .btn:hover { color: #000; }

/* Sections */
section { padding: 64px 0; }
.eyebrow { font: 700 14px/1.43 var(--font); text-transform: uppercase; letter-spacing: 0.04em; color: var(--primary-dark); margin: 0 0 8px; }
h1 { font: 700 48px/1.25 var(--font); margin: 0 0 16px; }
h2 { font: 700 36px/1.25 var(--font); margin: 0 0 12px; color: var(--ink); }
h3 { font: 700 20px/1.25 var(--font); margin: 0 0 8px; color: var(--ink); }
.lead { font-size: 20px; line-height: 1.6; max-width: 62ch; margin: 0; }

.hero { background: var(--dark); color: var(--on-dark); padding: 96px 0 88px; position: relative; }
.hero::after { content: ""; position: absolute; left: max(24px, calc((100% - 1280px) / 2 + 24px)); bottom: 0; width: 12px; height: 12px; background: var(--primary); }
.hero h1 { color: var(--on-dark); max-width: 18ch; }
.hero .lead { color: var(--on-dark-mute); }
.hero .actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 32px; }

.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; margin-top: 32px; padding: 0; list-style: none; counter-reset: step; }
.steps li { counter-increment: step; border: 1px solid var(--hairline); border-radius: var(--radius); padding: 24px; }
.steps li::before { content: counter(step); display: block; font: 700 36px/1.25 var(--font); color: var(--primary-dark); margin-bottom: 8px; }
.steps p, .card p { margin: 0; color: var(--body); }

.alt { background: var(--soft); border-top: 1px solid var(--hairline); border-bottom: 1px solid var(--hairline); }
.grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; margin-top: 32px; }
.card { position: relative; background: var(--canvas); border: 1px solid var(--hairline); border-radius: var(--radius); padding: 32px 24px 24px; }
.card::before { content: ""; position: absolute; top: -1px; left: -1px; width: 12px; height: 12px; background: var(--primary); }

.split { display: grid; grid-template-columns: 3fr 2fr; gap: 48px; align-items: start; }
.split p { max-width: 62ch; }
.fact { border: 1px solid var(--hairline); border-radius: var(--radius); padding: 24px; background: var(--canvas); }
.fact strong { display: block; font: 700 36px/1.25 var(--font); color: var(--primary-dark); }

.cta { background: var(--dark); color: var(--on-dark); }
.cta h2 { color: var(--on-dark); }
.cta p { color: var(--on-dark-mute); max-width: 60ch; margin: 0 0 24px; }
.cta a.mail { color: var(--primary); font-weight: 700; }

footer { background: var(--dark); color: var(--on-dark-mute); padding: 32px 0; border-top: 1px solid var(--hairline-strong); font-size: 14px; }
footer .wrap { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }

/* Admin login page */
.login { max-width: 420px; margin: 64px auto; position: relative; border: 1px solid var(--hairline); border-radius: var(--radius); padding: 32px; }
.login::before { content: ""; position: absolute; top: -1px; left: -1px; width: 12px; height: 12px; background: var(--primary); }
.login h1 { font-size: 24px; margin-bottom: 4px; }
.login p { color: var(--mute); margin: 0 0 16px; font-size: 15px; }
.login label { display: block; font-weight: 700; font-size: 14px; margin: 16px 0 6px; }
.login input { width: 100%; height: 44px; padding: 12px 16px; border: 1px solid var(--hairline); border-radius: var(--radius); font: inherit; }
.login input:focus { outline: none; border-color: var(--primary); box-shadow: inset 0 0 0 1px var(--primary); }
.login button { width: 100%; margin-top: 24px; }
.login .err { color: var(--error); font-size: 14px; margin-top: 12px; min-height: 20px; }

@media (max-width: 1024px) { .grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 768px) {
  h1 { font-size: 34px; }
  h2 { font-size: 28px; }
  .hero { padding: 64px 0 56px; }
  .nav ul li:not(:last-child) { display: none; }
  .steps, .grid, .split { grid-template-columns: 1fr; }
  .split { gap: 24px; }
}