/* BIT1 company site. Same approach as the product sites: plain files, no
   build step, no framework, no script. One accent, the blue the app icons
   share. Light and dark follow the system. */
:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --line: rgba(15, 23, 42, 0.10);
  --ink: #0f172a;
  --ink-soft: #55607a;
  --accent: #0b63f6;
  --accent-text: #0b5ce0;
  --accent-ink: #ffffff;
  --accent-soft: rgba(11, 99, 246, 0.10);
  --glow: radial-gradient(55% 60% at 80% 0%, rgba(11, 99, 246, 0.14), transparent 70%),
          radial-gradient(45% 55% at 5% 10%, rgba(124, 196, 255, 0.16), transparent 70%);
  --shadow: 0 1px 2px rgba(15, 23, 42, 0.06), 0 12px 32px rgba(15, 23, 42, 0.08);
  --radius: 18px;
  --pill: 980px;
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --bg: #0a0c11;
    --surface: #141821;
    --line: rgba(255, 255, 255, 0.10);
    --ink: #f3f5f9;
    --ink-soft: #a0a9bb;
    --accent: #3b82f6;
    --accent-text: #8fbcff;
    --accent-soft: rgba(96, 156, 255, 0.14);
    --glow: radial-gradient(55% 60% at 80% 0%, rgba(59, 130, 246, 0.20), transparent 70%),
            radial-gradient(45% 55% at 5% 10%, rgba(124, 196, 255, 0.08), transparent 70%);
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 16px 40px rgba(0, 0, 0, 0.45);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 72px; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.55 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI",
    Roboto, "Helvetica Neue", Arial, "Hiragino Sans", "PingFang SC",
    "Noto Sans CJK", sans-serif;
  letter-spacing: -0.01em;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 24px; }

a { color: var(--accent-text); text-decoration: none; }
a:hover { text-decoration: underline; }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }

h1, h2, h3 { margin: 0; letter-spacing: -0.025em; line-height: 1.1; text-wrap: balance; }
p { margin: 0; }

/* Header */
header.site {
  position: sticky; top: 0; z-index: 10;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(180%) blur(16px);
  -webkit-backdrop-filter: saturate(180%) blur(16px);
  border-bottom: 1px solid var(--line);
}
header.site .wrap { display: flex; align-items: center; justify-content: space-between; height: 56px; }
.brand { font-size: 24px; font-weight: 800; letter-spacing: -0.05em; color: var(--ink); }
.brand:hover { text-decoration: none; }
.brand span { color: var(--accent); }
header.site nav { display: flex; gap: 24px; font-size: 15px; }
header.site nav a { color: var(--ink-soft); }
header.site nav a:hover { color: var(--ink); text-decoration: none; }

/* Hero */
.hero { background: var(--glow); padding: 104px 0 96px; }
.eyebrow { font-size: 14px; font-weight: 600; color: var(--accent-text); letter-spacing: 0.02em; }
.hero h1 { font-size: clamp(40px, 7vw, 76px); font-weight: 800; margin: 0; }
.lede { font-size: clamp(18px, 2.2vw, 21px); color: var(--ink-soft); max-width: 58ch; }
.btn {
  display: inline-block; margin-top: 36px; padding: 13px 24px;
  background: var(--accent); color: var(--accent-ink);
  border-radius: var(--pill); font-weight: 600;
}
.btn:hover { text-decoration: none; filter: brightness(1.08); }

/* Sections */
section h2 { font-size: clamp(28px, 4vw, 40px); font-weight: 750; margin-bottom: 32px; }
.apps, .studio, .contact { padding: 80px 0; }
.studio { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }

/* App cards */
.grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.card {
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 28px; display: flex; flex-direction: column;
}
.card img { border-radius: 16px; display: block; margin-bottom: 22px; }
.question { font-size: 14px; font-weight: 600; color: var(--accent-text); margin-bottom: 6px; }
.card h3 { font-size: 26px; font-weight: 750; margin-bottom: 12px; display: flex; align-items: center; gap: 10px; }
.card > p:not(.question):not(.links) { color: var(--ink-soft); }
.tag {
  font-size: 12px; font-weight: 650; letter-spacing: 0.02em;
  color: var(--accent-text); background: var(--accent-soft);
  padding: 3px 10px; border-radius: var(--pill);
}
.links { margin-top: auto; padding-top: 22px; display: flex; flex-wrap: wrap; gap: 8px 20px; font-size: 15px; font-weight: 600; }
.links a::after { content: " →"; }
.soon { color: var(--ink-soft); font-weight: 500; }

/* Principles */
.principles { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 36px; }
.principles h3 { font-size: 19px; font-weight: 700; margin-bottom: 10px; }
.principles p { color: var(--ink-soft); font-size: 16px; }

/* Contact */
.contact p { font-size: 19px; color: var(--ink-soft); }
.contact a { font-weight: 600; }

/* Footer */
footer.site { border-top: 1px solid var(--line); padding: 28px 0 40px; font-size: 14px; color: var(--ink-soft); }
footer.site .wrap { display: flex; flex-wrap: wrap; gap: 8px 22px; align-items: center; }
footer.site .spacer { flex: 1; }
footer.site a { color: var(--ink-soft); }

/* Documents (product help, privacy) */
.doc { padding: 64px 0 88px; }
.doc .wrap { max-width: 760px; }
.doc h1 { font-size: clamp(34px, 5vw, 48px); font-weight: 800; margin: 6px 0 10px; }
.doc h2 { font-size: 22px; font-weight: 700; margin: 40px 0 12px; }
.doc p, .doc li, .doc dd { color: var(--ink-soft); }
.doc p + p { margin-top: 12px; }
.doc ul { margin: 0; padding-left: 22px; }
.doc li + li { margin-top: 8px; }
.doc strong, .doc dt { color: var(--ink); font-weight: 650; }
.doc dl { margin: 0; }
.doc dt + dd { margin: 4px 0 0; }
.doc dd + dt { margin-top: 18px; }
.doc .updated { font-size: 15px; margin-bottom: 28px; }
.doc .lede { margin-top: 4px; }
.doc .appicon { border-radius: 16px; display: block; margin-bottom: 18px; }
.doc .more { margin-top: 24px; font-weight: 600; }
header.site nav a[aria-current="page"] { color: var(--ink); }

/* 404 */
.notfound { padding: 140px 0; text-align: left; }
.notfound h1 { font-size: clamp(36px, 6vw, 60px); font-weight: 800; margin-bottom: 16px; }
.notfound p { color: var(--ink-soft); font-size: 19px; }

@media (max-width: 760px) {
  .wrap { padding: 0 16px; }
  .hero { padding: 64px 0 56px; }
  .apps, .studio, .contact { padding: 56px 0; }
  .grid, .principles { grid-template-columns: 1fr; }
  .principles { gap: 28px; }
  header.site nav { gap: 18px; }
  .card { padding: 22px; }
}

@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }