/* 99Pages base.css — vars, reset, typography, layout primitives, nav, footer.
   Apple 极简 + 暖白底（feedback_design.md）。 */

:root {
  --bg: #FAF8F3;
  --bg-soft: #F2EFE7;
  --bg-card: #FFFFFF;
  --ink: #1A1A1A;
  --ink-soft: #4A4A4A;
  --muted: #8A8680;
  --accent: #D9624A;
  --accent-soft: #F4D9CF;
  --line: #E8E3D6;
  --radius: 16px;
  --radius-lg: 24px;
  --shadow: 0 1px 2px rgba(0,0,0,0.04), 0 8px 24px rgba(0,0,0,0.04);
  --shadow-hover: 0 2px 4px rgba(0,0,0,0.06), 0 16px 40px rgba(0,0,0,0.08);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  letter-spacing: 0.01em;
}

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

/* === Nav === */
.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 22px 48px;
  max-width: 1200px;
  margin: 0 auto;
}
.brand {
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.02em;
}
.nav-links { display: flex; gap: 28px; align-items: center; }
.nav-links a { font-size: 15px; color: var(--ink-soft); transition: color 0.2s; }
.nav-links a:hover { color: var(--ink); }
.nav-links .muted { color: var(--muted); }

/* === Buttons === */
.btn {
  display: inline-block;
  padding: 16px 32px;
  border-radius: 999px;
  font-size: 16px;
  font-weight: 500;
  transition: all 0.2s;
  cursor: pointer;
  border: 1px solid transparent;
}
.btn-primary { background: var(--ink); color: var(--bg); }
.btn-primary:hover { background: var(--accent); transform: translateY(-1px); }
.btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--line);
}
.btn-ghost:hover { border-color: var(--ink); }
.btn-link {
  padding: 0;
  background: transparent;
  color: var(--accent);
  font-weight: 500;
}
.btn-link:hover { text-decoration: underline; }

/* === Section common === */
section { padding: 100px 48px; max-width: 1200px; margin: 0 auto; }
.section-title {
  font-size: 40px;
  font-weight: 700;
  letter-spacing: -0.02em;
  text-align: center;
  margin-bottom: 16px;
  line-height: 1.2;
}
.section-sub {
  font-size: 18px;
  color: var(--ink-soft);
  text-align: center;
  margin-bottom: 64px;
}
.muted { color: var(--muted); }
.accent { color: var(--accent); }

/* === Footer === */
.footer {
  background: var(--bg-soft);
  padding: 64px 48px 32px;
  margin-top: 80px;
}
.footer-cols {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 48px;
}
.footer-cols h4 {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--ink);
}
.footer-cols a {
  display: block;
  color: var(--ink-soft);
  font-size: 14px;
  padding: 4px 0;
  transition: color 0.2s;
}
.footer-cols a:hover { color: var(--accent); }
.footer-bottom {
  max-width: 1200px;
  margin: 48px auto 0;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  text-align: center;
}

/* === Responsive === */
@media (max-width: 768px) {
  .nav { padding: 16px 24px; }
  .nav-links { gap: 16px; }
  .nav-links a:not(.brand) { font-size: 13px; }
  section { padding: 64px 24px; }
  .section-title { font-size: 28px; }
  .section-sub { font-size: 16px; margin-bottom: 40px; }
  .footer-cols { grid-template-columns: 1fr 1fr; gap: 32px; }
}