:root, html[data-theme="dark"] {
  --bg0: #0f1419;
  --bg1: #182029;
  --ink: #e8eef4;
  --muted: #8b9aab;
  --line: #2a3644;
  --accent: #3d9cf0;
  --accent2: #2a7ec4;
  --card: #151c24;
  --ok: #6bcb8a;
  --warn: #e6b35c;
  --btn-fill: #1c2631;
  --guide-glow: rgba(61, 156, 240, 0.16);
  --hero-glow2: rgba(107, 203, 138, 0.08);
  color-scheme: dark;
}

html[data-theme="light"] {
  --bg0: #f4f7fb;
  --bg1: #e8eef6;
  --ink: #142033;
  --muted: #5b6b7c;
  --line: #d5dee8;
  --accent: #1f7fd6;
  --accent2: #1766ad;
  --card: #ffffff;
  --ok: #1f8a4c;
  --warn: #b7791f;
  --btn-fill: #ffffff;
  --guide-glow: rgba(31, 127, 214, 0.12);
  --hero-glow2: rgba(31, 138, 76, 0.08);
  color-scheme: light;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  font: 16px/1.55 "IBM Plex Sans", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background:
    radial-gradient(900px 420px at 12% -10%, var(--guide-glow), transparent 55%),
    radial-gradient(700px 380px at 100% 0%, var(--hero-glow2), transparent 50%),
    linear-gradient(180deg, var(--bg0), var(--bg1));
}

.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  max-width: 1080px;
  margin: 0 auto;
  padding: 20px 20px 0;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: Sora, "IBM Plex Sans", sans-serif;
  font-weight: 700;
  font-size: 18px;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: -0.02em;
}
.brand-logo {
  display: block;
  border-radius: 8px;
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--line) 70%, transparent);
  background: #0b1f3a;
  flex: 0 0 auto;
}
.brand-logo.sm { border-radius: 5px; }
.brand-inline {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.top nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 12px;
  align-items: center;
}
.top nav a:not(.btn) {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
}
.top nav a:not(.btn):hover { color: var(--ink); }

.theme-toggle {
  min-height: 34px;
  padding: 0 12px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--btn-fill);
  color: var(--ink);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}
.theme-toggle:hover { border-color: var(--accent); }

.hero {
  max-width: 1080px;
  margin: 0 auto;
  padding: clamp(48px, 10vh, 96px) 20px 28px;
}
.eyebrow {
  margin: 0 0 12px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: Sora, sans-serif;
  font-size: 13px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
}
.hero h1 {
  margin: 0 0 14px;
  font-family: Sora, sans-serif;
  font-size: clamp(34px, 6vw, 52px);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.12;
  max-width: 12em;
}
.lede {
  margin: 0 0 28px;
  max-width: 34em;
  color: var(--muted);
  font-size: 18px;
}
.cta { display: flex; flex-wrap: wrap; gap: 12px; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 0 14px;
  border-radius: 9px;
  border: 1px solid var(--line);
  background: var(--btn-fill);
  color: var(--ink);
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
}
.btn:hover { border-color: var(--accent); }
.btn.primary {
  background: linear-gradient(180deg, var(--accent), var(--accent2));
  border-color: transparent;
  color: #ffffff;
  text-shadow: 0 1px 0 rgba(0, 0, 0, 0.18);
}
.btn.accent {
  background: linear-gradient(180deg, #3ecf7a, #23a85a);
  border-color: transparent;
  color: #ffffff;
  text-shadow: 0 1px 0 rgba(0, 0, 0, 0.18);
}
.btn.ghost { background: transparent; }
.btn.lg { min-height: 46px; padding: 0 20px; font-size: 15px; }

.section {
  max-width: 1080px;
  margin: 0 auto;
  padding: 28px 20px 12px;
}
.section h2 {
  margin: 0 0 8px;
  font-family: Sora, sans-serif;
  font-size: 24px;
  letter-spacing: -0.02em;
}
.section-lede { margin: 0 0 20px; color: var(--muted); }

.guide-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}
.guide {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  text-decoration: none;
  color: inherit;
  border: 1px solid var(--line);
  background: color-mix(in srgb, var(--card) 92%, transparent);
  border-radius: 16px;
  padding: 18px;
  transition: border-color .15s, transform .12s;
}
.guide:hover { border-color: var(--accent); transform: translateY(-1px); }
.guide.featured {
  border-color: color-mix(in srgb, var(--ok) 45%, var(--line));
  background:
    radial-gradient(420px 160px at 100% 0%, color-mix(in srgb, var(--ok) 16%, transparent), transparent 60%),
    color-mix(in srgb, var(--card) 92%, transparent);
}
.guide-n {
  flex: 0 0 auto;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--accent);
  color: #ffffff;
  font-family: Sora, sans-serif;
  font-weight: 700;
}
.guide.featured .guide-n { background: #23a85a; color: #ffffff; }
.guide h3 {
  margin: 0 0 6px;
  font-family: Sora, sans-serif;
  font-size: 18px;
}
.guide p { margin: 0 0 10px; color: var(--muted); font-size: 14px; }
.guide-cta { color: var(--accent); font-size: 14px; font-weight: 650; }

.plans-wrap { display: grid; gap: 14px; }
.plans {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}
.plans.plans-row2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.plan {
  border: 1px solid var(--line);
  background: color-mix(in srgb, var(--card) 92%, transparent);
  border-radius: 14px;
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.plan.featured { border-color: color-mix(in srgb, var(--accent) 55%, var(--line)); }
.plan .tag {
  align-self: flex-start;
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ok);
}
.plan h3 {
  margin: 0;
  font-family: Sora, sans-serif;
  font-size: 18px;
}
.price {
  font-family: Sora, sans-serif;
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.03em;
}
.price small { font-size: 13px; color: var(--muted); font-weight: 500; }
.meta { margin: 0; color: var(--muted); font-size: 13px; flex: 1; }
.plan .btn { margin-top: 8px; width: 100%; }

.faq {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 14px;
}
.faq article {
  border-top: 1px solid var(--line);
  padding-top: 14px;
}
.faq h3 {
  margin: 0 0 6px;
  font-size: 15px;
  font-family: Sora, sans-serif;
}
.faq p { margin: 0; color: var(--muted); font-size: 14px; }
.faq a { color: var(--accent); }

.foot {
  max-width: 1080px;
  margin: 40px auto 0;
  padding: 24px 20px 48px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px 18px;
  color: var(--muted);
  font-size: 13px;
  border-top: 1px solid var(--line);
}
.foot a { color: var(--accent); text-decoration: none; }

@media (max-width: 860px) {
  .plans,
  .plans.plans-row2,
  .guide-grid {
    grid-template-columns: 1fr;
  }
}
@media (max-width: 720px) {
  .top { flex-direction: column; align-items: flex-start; }
}