/* tailOS — global styles */
:root {
  --bg: #0a0b0d;
  --bg-1: #0e1014;
  --bg-2: #14171c;
  --bg-3: #1b1f26;
  --line: #23272f;
  --line-soft: #1a1d23;
  --ink: #f4f4f5;
  --ink-2: #c8ccd3;
  --ink-3: #8b9099;
  --ink-4: #5a606b;
  --accent: #22c5a8;        /* tailOS mint */
  --accent-soft: rgba(34, 197, 168, 0.12);
  --accent-line: rgba(34, 197, 168, 0.32);
  --warm: #f59e0b;
  --warm-soft: rgba(245, 158, 11, 0.14);
  --rose: #f87171;
  --blue: #60a5fa;
  --violet: #a78bfa;
  --serif: "Noto Serif TC", "Source Han Serif TC", "Songti TC", "PingFang TC", serif;
  --sans: "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", system-ui, -apple-system, sans-serif;
  --mono: "JetBrains Mono", "SF Mono", ui-monospace, monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; }

::selection { background: var(--accent); color: #08130f; }

/* layout primitives */
.shell {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 48px;
}
@media (max-width: 720px) {
  .shell { padding: 0 24px; }
}

.eyebrow {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.eyebrow .dot {
  display: inline-block;
  width: 6px; height: 6px;
  border-radius: 999px;
  background: var(--accent);
  margin-right: 8px;
  vertical-align: 1px;
}

.serif {
  font-family: var(--serif);
  font-weight: 500;
  letter-spacing: -0.01em;
}

/* nav */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  background: rgba(10, 11, 13, 0.72);
  border-bottom: 1px solid var(--line-soft);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 48px;
  max-width: 1440px;
  margin: 0 auto;
}
.nav-brand {
  display: flex; align-items: center; gap: 10px;
  font-weight: 600; letter-spacing: -0.01em;
}
.nav-brand img {
  width: 32px; height: 32px;
  filter: brightness(0) invert(1);
}
.nav-brand .brand-name {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro", "Segoe UI", system-ui, sans-serif;
  font-weight: 600;
  font-size: 19px;
  letter-spacing: -0.02em;
}
.nav-brand .brand-os {
  color: var(--accent);
  font-weight: 600;
}
.nav-brand .dot { color: var(--accent); }
.nav-links {
  display: flex; gap: 32px;
  font-size: 14px; color: var(--ink-2);
}
.nav-links a:hover { color: var(--ink); }
.nav-cta {
  display: flex; gap: 10px; align-items: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  transition: all 160ms ease;
  white-space: nowrap;
}
.btn:hover { border-color: var(--ink-3); }
.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #08130f;
}
.btn-primary:hover {
  background: #2dd6b8;
  border-color: #2dd6b8;
}
.btn-lg { padding: 14px 22px; font-size: 15px; }

/* section primitives */
section {
  position: relative;
  padding: 120px 0;
  border-bottom: 1px solid var(--line-soft);
}
@media (max-width: 720px) {
  section { padding: 80px 0; }
}

.section-head {
  display: flex;
  flex-direction: column;
  gap: 18px;
  margin-bottom: 64px;
  max-width: 820px;
}
.section-head h2 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(36px, 5vw, 64px);
  line-height: 1.05;
  letter-spacing: -0.015em;
  margin: 0;
}
.section-head h2 em {
  font-style: italic;
  color: var(--accent);
  font-weight: 500;
}
.section-head p {
  font-size: 18px;
  color: var(--ink-2);
  line-height: 1.55;
  max-width: 680px;
  margin: 0;
}

/* card primitives */
.card {
  background: var(--bg-1);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 28px;
  transition: border-color 200ms, transform 200ms, background 200ms;
}
.card:hover {
  border-color: var(--ink-4);
  background: var(--bg-2);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--ink-3);
  background: var(--bg-1);
}
.tag.tag-accent { color: var(--accent); border-color: var(--accent-line); background: var(--accent-soft); }
.tag.tag-warm { color: var(--warm); border-color: rgba(245,158,11,0.3); background: var(--warm-soft); }

/* utility */
.grid-bg {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(to right, rgba(255,255,255,0.025) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255,255,255,0.025) 1px, transparent 1px);
  background-size: 64px 64px;
  pointer-events: none;
  mask-image: radial-gradient(ellipse at center, black 30%, transparent 75%);
}

.fade-in {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 700ms ease, transform 700ms ease;
}
.fade-in.in {
  opacity: 1;
  transform: translateY(0);
}

/* animations */
@keyframes pulse-soft {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}
.pulse { animation: pulse-soft 2.4s ease-in-out infinite; }

@keyframes slide-in-up {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}

/* scrollbar styling on dark */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--bg-3); border-radius: 999px; }
::-webkit-scrollbar-thumb:hover { background: var(--line); }