/* Denizcilik Lab — black/white, minimal. System fonts only, no external assets. */

:root {
  --bg: #000;
  --surface: #0d0d0f;
  --surface-2: #151518;
  --line: rgba(255, 255, 255, 0.1);
  --text: #f5f5f7;
  --text-2: rgba(245, 245, 247, 0.72);
  --text-3: rgba(245, 245, 247, 0.5);
  --radius: 18px;
  --max: 1080px;
  --prose: 720px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-display: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color-scheme: dark;
}

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

html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a { color: var(--text); text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { color: #fff; }

:focus-visible { outline: 2px solid #fff; outline-offset: 3px; border-radius: 6px; }

.skip-link {
  position: absolute;
  left: 16px;
  top: -48px;
  padding: 8px 14px;
  background: #fff;
  color: #000;
  border-radius: 10px;
  z-index: 10;
  font-weight: 600;
}
.skip-link:focus { top: 12px; }

.container { width: 100%; max-width: var(--max); margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  background: rgba(0, 0, 0, 0.78);
  -webkit-backdrop-filter: saturate(180%) blur(18px);
  backdrop-filter: saturate(180%) blur(18px);
  border-bottom: 1px solid var(--line);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  height: 56px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  letter-spacing: -0.01em;
  text-decoration: none;
}
.brand img { width: 28px; height: 28px; border-radius: 7px; }
.site-nav ul { display: flex; gap: 20px; list-style: none; margin: 0; padding: 0; }
.site-nav a { color: var(--text-2); text-decoration: none; font-size: 14px; }
.site-nav a:hover,
.site-nav a[aria-current="page"] { color: var(--text); }

/* Hero */
.hero { padding: 88px 0 72px; text-align: center; }
.hero-icon {
  width: 128px;
  height: 128px;
  margin: 0 auto 28px;
  border-radius: 28px;
  box-shadow: 0 0 0 1px var(--line), 0 24px 64px rgba(255, 255, 255, 0.08);
}
.eyebrow {
  margin: 0 0 14px;
  color: var(--text-3);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}
.hero h1 {
  margin: 0 auto;
  max-width: 14ch;
  font-family: var(--font-display);
  font-size: clamp(38px, 7vw, 68px);
  line-height: 1.05;
  letter-spacing: -0.035em;
  font-weight: 700;
}
.hero .lead {
  margin: 22px auto 0;
  max-width: 34em;
  color: var(--text-2);
  font-size: clamp(17px, 2.2vw, 20px);
}
.cta { margin-top: 36px; display: flex; flex-direction: column; align-items: center; gap: 12px; }
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 52px;
  padding: 0 26px;
  border-radius: 14px;
  background: #fff;
  color: #000;
  font-weight: 600;
  text-decoration: none;
}
.button:hover { color: #000; background: #e8e8ed; }
.button svg { width: 20px; height: 20px; }
.cta-note { margin: 0; color: var(--text-3); font-size: 14px; }
[hidden] { display: none !important; }

/* Features */
.section { padding: 72px 0; border-top: 1px solid var(--line); }
.section-title {
  margin: 0 0 8px;
  text-align: center;
  font-family: var(--font-display);
  font-size: clamp(28px, 4vw, 40px);
  letter-spacing: -0.025em;
  line-height: 1.15;
}
.section-sub { margin: 0 auto 44px; max-width: 32em; text-align: center; color: var(--text-2); }
.features {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.feature {
  padding: 26px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.feature-icon {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  margin-bottom: 18px;
  border-radius: 12px;
  background: var(--surface-2);
  border: 1px solid var(--line);
}
.feature-icon svg { width: 22px; height: 22px; stroke: #fff; fill: none; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.feature h3 { margin: 0 0 6px; font-size: 17px; letter-spacing: -0.01em; }
.feature p { margin: 0; color: var(--text-2); font-size: 15px; line-height: 1.55; }

/* Prose (legal / support) */
.page-head { padding: 64px 0 28px; }
.page-head h1 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(32px, 5vw, 48px);
  letter-spacing: -0.03em;
  line-height: 1.1;
}
.page-head p { margin: 12px 0 0; color: var(--text-3); font-size: 15px; }
.prose { max-width: var(--prose); padding-bottom: 80px; }
.prose h2 {
  margin: 44px 0 12px;
  font-size: 22px;
  letter-spacing: -0.015em;
  line-height: 1.3;
}
.prose h3 { margin: 26px 0 8px; font-size: 17px; }
.prose p,
.prose li { color: var(--text-2); }
.prose ul { padding-left: 1.25em; }
.prose li { margin: 6px 0; }
.prose strong { color: var(--text); font-weight: 600; }
.prose .toc {
  margin: 8px 0 8px;
  padding: 20px 24px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.prose .toc ol { margin: 0; padding-left: 1.25em; columns: 2; column-gap: 32px; }
.prose .toc li { margin: 4px 0; break-inside: avoid; }
.prose .toc a { color: var(--text-2); text-decoration: none; }
.prose .toc a:hover { color: var(--text); text-decoration: underline; }
.callout {
  margin: 20px 0;
  padding: 18px 20px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
}
.callout p { margin: 0; }

/* Support */
.prose .help-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin: 8px 0 0;
  padding: 0;
  list-style: none;
}
.help-card {
  padding: 22px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.help-card h2 { margin: 0 0 8px; font-size: 17px; }
.help-card p,
.help-card li { margin: 0; color: var(--text-2); font-size: 15px; }
.help-card ol { margin: 8px 0 0; padding-left: 1.2em; }
.help-card li { margin: 4px 0; }
.contact {
  margin-top: 28px;
  padding: 28px;
  text-align: center;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.contact h2 { margin: 0 0 8px; font-size: 22px; }
.contact p { margin: 0 0 18px; color: var(--text-2); }

/* Footer */
.site-footer { border-top: 1px solid var(--line); padding: 32px 0 40px; color: var(--text-3); font-size: 14px; }
.site-footer .container { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 16px; }
.site-footer p { margin: 0; }
.site-footer ul { display: flex; flex-wrap: wrap; gap: 20px; list-style: none; margin: 0; padding: 0; }
.site-footer a { color: var(--text-2); text-decoration: none; }
.site-footer a:hover { color: var(--text); }

@media (max-width: 860px) {
  .features { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 600px) {
  body { font-size: 16px; }
  .site-nav ul { gap: 14px; }
  .site-nav .nav-home { display: none; }
  .hero { padding: 56px 0 56px; }
  .hero-icon { width: 104px; height: 104px; border-radius: 23px; }
  .features,
  .prose .help-grid { grid-template-columns: 1fr; }
  .section { padding: 56px 0; }
  .prose .toc ol { columns: 1; }
  .site-footer .container { flex-direction: column; align-items: flex-start; }
}

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}