/* ============================================================
   KaiLab — landing site styles
   Palette: warm cream + ink + coral/indigo accents
   BRAND rename: change --brand / wordmark colors here.
   ============================================================ */

:root {
  --bg: #fdfaf6;
  --bg-alt: #f5efe7;
  --card: #ffffff;
  --ink: #23252e;
  --ink-soft: #5b5f6b;
  --line: #ece4d8;
  --accent: #ff6b4a;      /* warm coral — primary CTA */
  --accent-ink: #ffffff;
  --accent-2: #4f46e5;    /* indigo — links / secondary */
  --accent-2-soft: #eef0ff;
  --radius: 16px;
  --shadow: 0 1px 2px rgba(35,37,46,.05), 0 8px 24px rgba(35,37,46,.06);
  --shadow-hover: 0 2px 6px rgba(35,37,46,.08), 0 16px 40px rgba(35,37,46,.10);
  --maxw: 1080px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

/* ---------- avatar ---------- */
.avatar {
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  background: var(--bg);
}
.avatar-sm {
  width: 44px;
  height: 44px;
  border: 2px solid var(--line);
}
.avatar-card {
  width: 72px;
  height: 72px;
  margin-bottom: 10px;
  border: 2px solid var(--line);
}

/* ---------- wordmark ---------- */
.brand-kai {
  font-family: "Caveat", "Comic Sans MS", cursive;
  font-weight: 700;
  font-size: 1.5rem;
  color: var(--accent);
  letter-spacing: .5px;
}
.brand-home {
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--ink);
  letter-spacing: -.5px;
}

/* ---------- nav ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(253,250,246,.82);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  gap: 20px;
}
.nav-links {
  display: flex;
  gap: 22px;
  margin-left: 8px;
  font-size: .95rem;
  color: var(--ink-soft);
}
.nav-links a:hover { color: var(--ink); }
.nav-gh {
  padding: 4px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--ink) !important;
}
.nav-gh:hover { border-color: var(--ink-soft); }
.nav-cta { margin-left: auto; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: .95rem;
  padding: 11px 20px;
  border-radius: 999px;
  cursor: pointer;
  transition: transform .12s ease, box-shadow .12s ease, background .12s ease;
  white-space: nowrap;
}
.btn-lg { padding: 14px 28px; font-size: 1.02rem; }
.btn-primary {
  background: var(--accent);
  color: var(--accent-ink);
  box-shadow: 0 6px 18px rgba(255,107,74,.30);
}
.btn-primary:hover { transform: translateY(-1px); box-shadow: 0 10px 26px rgba(255,107,74,.38); }
.btn-ghost {
  background: transparent;
  color: var(--ink);
  border: 1.5px solid var(--line);
}
.btn-ghost:hover { border-color: var(--ink-soft); transform: translateY(-1px); }

/* ---------- hero ---------- */
.hero {
  padding: 84px 24px 72px;
  background:
    radial-gradient(1200px 420px at 50% -10%, rgba(255,107,74,.10), transparent 60%),
    var(--bg);
}
.hero-inner {
  max-width: 760px;
  margin: 0 auto;
  text-align: center;
}
.badge {
  display: inline-block;
  font-size: .85rem;
  font-weight: 600;
  color: var(--accent-2);
  background: var(--accent-2-soft);
  padding: 6px 14px;
  border-radius: 999px;
  margin-bottom: 22px;
}
.hero h1 {
  font-size: clamp(2.2rem, 6vw, 3.6rem);
  line-height: 1.12;
  margin: 0 0 18px;
  letter-spacing: -.5px;
  font-weight: 800;
}
.lede {
  font-size: clamp(1.02rem, 2.4vw, 1.22rem);
  color: var(--ink-soft);
  margin: 0 auto 30px;
  max-width: 620px;
}
.lede strong { color: var(--ink); font-weight: 700; }
.cta-row {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}
.hero-sub {
  margin-top: 20px;
  font-size: .85rem;
  color: var(--ink-soft);
  opacity: .85;
}

/* ---------- sections ---------- */
.section { padding: 72px 24px; }
.section-alt { background: var(--bg-alt); }
.section-head {
  max-width: 720px;
  margin: 0 auto 44px;
  text-align: center;
}
.section-head h2 {
  font-size: clamp(1.7rem, 4vw, 2.4rem);
  margin: 0 0 12px;
  font-weight: 800;
  letter-spacing: -.5px;
}
.section-head p { color: var(--ink-soft); margin: 0; font-size: 1.05rem; }
.section-head p strong { color: var(--ink); }
.eyebrow {
  display: inline-block;
  font-size: .8rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 8px;
}

/* ---------- grids & cards ---------- */
.grid { display: grid; gap: 20px; max-width: var(--maxw); margin: 0 auto; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 24px;
  box-shadow: var(--shadow);
  transition: transform .14s ease, box-shadow .14s ease;
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-hover); }
.card-icon { font-size: 1.8rem; margin-bottom: 12px; }
.card h3 { margin: 0 0 8px; font-size: 1.12rem; font-weight: 700; }
.card p { margin: 0; color: var(--ink-soft); font-size: .96rem; }
.card code {
  background: var(--bg-alt);
  padding: 1px 6px;
  border-radius: 6px;
  font-size: .9em;
  color: var(--accent-2);
}
.card-note { border-style: dashed; }
.tag {
  display: inline-block;
  font-size: .7rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 999px;
  vertical-align: middle;
  margin-left: 6px;
  background: var(--bg-alt);
  color: var(--ink-soft);
}
.tag-done { background: #e7f7ec; color: #1a8a4a; }
.tag-plan { background: #fff3e6; color: #c2641a; }

.section-cta {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 40px;
}

/* ---------- opensource (致谢) ---------- */
.oss-body { max-width: 760px; margin: 0 auto; }
.oss-body p {
  color: var(--ink-soft);
  font-size: 1.04rem;
  margin: 0 0 16px;
}
.oss-body p strong { color: var(--ink); }
.oss-chips {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 10px;
}
.oss-chip {
  font-size: .85rem;
  font-weight: 600;
  color: var(--accent-2);
  background: var(--accent-2-soft);
  padding: 6px 14px;
  border-radius: 999px;
}

/* ---------- CTA band ---------- */
.section-cta-band { padding: 80px 24px; }
.cta-band {
  max-width: 760px;
  margin: 0 auto;
  text-align: center;
  background: linear-gradient(135deg, #fff 0%, #fff6f2 100%);
  border: 1px solid var(--line);
  border-radius: 24px;
  padding: 52px 32px;
  box-shadow: var(--shadow);
}
.cta-band h2 { font-size: clamp(1.8rem, 4.5vw, 2.6rem); margin: 0 0 12px; font-weight: 800; }
.cta-band p { color: var(--ink-soft); margin: 0 auto 28px; max-width: 540px; font-size: 1.05rem; }

/* ---------- footer ---------- */
.footer {
  border-top: 1px solid var(--line);
  background: var(--bg-alt);
  padding: 44px 24px 32px;
}
.footer-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 24px;
  flex-wrap: wrap;
}
.footer-tag { margin: 6px 0 0; color: var(--ink-soft); font-size: .9rem; }
.footer-identity {
  display: flex;
  align-items: center;
  gap: 14px;
}
.footer-links { display: flex; gap: 22px; flex-wrap: wrap; }
.footer-links a { color: var(--ink-soft); font-size: .95rem; }
.footer-links a:hover { color: var(--ink); }
.footer-privacy {
  max-width: var(--maxw);
  margin: 28px auto 0;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  font-size: .82rem;
  color: var(--ink-soft);
  text-align: center;
}
.footer-copy {
  text-align: center;
  font-size: .8rem;
  color: var(--ink-soft);
  opacity: .7;
  margin: 8px 0 0;
}

/* ---------- responsive ---------- */
@media (max-width: 860px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .nav-links { display: none; }
  .grid-4 { grid-template-columns: 1fr; }
  .grid-3 { grid-template-columns: 1fr; }
  .hero { padding: 60px 20px 52px; }
  .section { padding: 56px 20px; }
}