:root {
  --bg: #f4f7fb;
  --surface: #ffffff;
  --ink: #0f172a;
  --muted: #64748b;
  --line: #e2e8f0;
  --brand: #2563eb;
  --brand-2: #0ea5e9;
  --brand-ink: #1e3a8a;
  --ok: #059669;
  --warn: #d97706;
  --shadow: 0 12px 40px rgba(15, 23, 42, 0.08);
  --radius: 18px;
  --radius-sm: 12px;
  --max: 1120px;
  --font: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background:
    radial-gradient(900px 420px at 10% -10%, rgba(37, 99, 235, 0.12), transparent 60%),
    radial-gradient(700px 360px at 90% 0%, rgba(14, 165, 233, 0.1), transparent 55%),
    var(--bg);
  line-height: 1.6;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { margin: 0; padding: 0; list-style: none; }
button { font: inherit; }

.container { width: min(100% - 2rem, var(--max)); margin-inline: auto; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(14px);
  background: rgba(244, 247, 251, 0.86);
  border-bottom: 1px solid rgba(226, 232, 240, 0.9);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 72px;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.logo-mark {
  width: 38px;
  height: 38px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  color: #fff;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  box-shadow: 0 8px 18px rgba(37, 99, 235, 0.28);
  font-size: 0.85rem;
}

.logo-text span { color: var(--brand); }

.nav-links {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
}

.nav-links a {
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  color: var(--muted);
  font-size: 0.95rem;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--brand-ink);
  background: #e8f0ff;
}

.lang-switch {
  display: inline-flex;
  padding: 0.2rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
}

.lang-switch button {
  border: 0;
  background: transparent;
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  color: var(--muted);
  cursor: pointer;
}

.lang-switch button.active {
  background: var(--brand);
  color: #fff;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  min-height: 48px;
  padding: 0.75rem 1.25rem;
  border-radius: 14px;
  border: 1px solid transparent;
  font-weight: 700;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
}

.btn:hover { transform: translateY(-1px); }

.btn-primary {
  color: #fff;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  box-shadow: 0 12px 24px rgba(37, 99, 235, 0.28);
}

.btn-secondary {
  color: var(--brand-ink);
  background: #fff;
  border-color: #bfd3ff;
}

.btn-ghost {
  color: var(--ink);
  background: #f8fafc;
  border-color: var(--line);
}

.hero {
  padding: 3.2rem 0 2rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 1.5rem;
  align-items: center;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.tag {
  padding: 0.28rem 0.7rem;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--brand-ink);
  background: #eaf2ff;
  border: 1px solid #cfe0ff;
}

.hero h1 {
  margin: 0 0 0.9rem;
  font-size: clamp(2rem, 4vw, 3.1rem);
  line-height: 1.15;
  letter-spacing: -0.03em;
}

.hero h1 em {
  font-style: normal;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-lead {
  margin: 0 0 1.4rem;
  color: var(--muted);
  font-size: 1.05rem;
  max-width: 54ch;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1.4rem;
}

.trust-row {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.75rem;
}

.trust-item {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 0.85rem 0.95rem;
  box-shadow: var(--shadow);
}

.trust-item strong {
  display: block;
  font-size: 1.05rem;
}

.trust-item span {
  color: var(--muted);
  font-size: 0.86rem;
}

.cta-panel {
  position: relative;
  overflow: hidden;
  background: linear-gradient(160deg, #102a56 0%, #1d4ed8 55%, #0284c7 100%);
  color: #fff;
  border-radius: 28px;
  padding: 1.4rem;
  box-shadow: 0 24px 50px rgba(29, 78, 216, 0.28);
  min-height: 420px;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.cta-panel::before {
  content: "";
  position: absolute;
  inset: auto -20% -30% 20%;
  height: 220px;
  background: radial-gradient(circle, rgba(255,255,255,0.22), transparent 70%);
  pointer-events: none;
}

.cta-panel-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  position: relative;
  z-index: 1;
}

.cta-kicker {
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  opacity: 0.8;
}

.cta-panel h2 {
  margin: 0.35rem 0 0;
  font-size: 1.55rem;
  line-height: 1.25;
}

.cta-badge {
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  background: rgba(255,255,255,0.14);
  border: 1px solid rgba(255,255,255,0.22);
  font-size: 0.8rem;
  white-space: nowrap;
}

.cta-visual {
  position: relative;
  z-index: 1;
  border-radius: 18px;
  overflow: hidden;
  border: 1px solid rgba(255,255,255,0.18);
  background: rgba(255,255,255,0.08);
}

.cta-visual img {
  width: 100%;
  height: 180px;
  object-fit: cover;
}

.cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
  position: relative;
  z-index: 1;
  margin-top: auto;
}

.cta-actions .btn-primary {
  background: #fff;
  color: var(--brand-ink);
  box-shadow: none;
}

.cta-actions .btn-secondary {
  background: transparent;
  color: #fff;
  border-color: rgba(255,255,255,0.35);
}

.section {
  padding: 3.2rem 0;
}

.section-head {
  margin-bottom: 1.4rem;
}

.section-kicker {
  display: inline-block;
  margin-bottom: 0.45rem;
  color: var(--brand);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.section-head h2 {
  margin: 0 0 0.45rem;
  font-size: clamp(1.55rem, 2.5vw, 2.1rem);
  letter-spacing: -0.02em;
}

.section-head p {
  margin: 0;
  color: var(--muted);
  max-width: 60ch;
}

.comp-card,
.platform-card,
.feature-card,
.recommend-card,
.scene-card,
.faq-item,
.step-card,
.compat-item,
.download-card,
.docs-panel,
.flow-panel,
.preview-panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.platform-grid,
.feature-grid,
.recommend-grid,
.scene-grid,
.faq-grid,
.compat-grid {
  display: grid;
  gap: 1rem;
}

.platform-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.feature-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.recommend-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.scene-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.faq-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.compat-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }

.platform-card,
.feature-card,
.recommend-card,
.scene-card,
.faq-item,
.step-card,
.compat-item,
.docs-panel {
  padding: 1.15rem 1.2rem;
}

.os-badge,
.badge,
.status,
.step-label,
.feature-index,
.compat-dot {
  display: inline-flex;
  align-items: center;
  padding: 0.22rem 0.65rem;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 800;
}

.os-badge,
.badge,
.step-label,
.feature-index {
  color: var(--brand-ink);
  background: #eaf2ff;
}

.status {
  color: #065f46;
  background: #d1fae5;
}

.compat-dot {
  color: #075985;
  background: #e0f2fe;
  margin-bottom: 0.7rem;
}

.platform-card h3,
.feature-card h3,
.recommend-card h3,
.scene-card h3,
.faq-item h3,
.step-card h3,
.compat-item h3,
.docs-panel h3,
.download-card h3 {
  margin: 0.7rem 0 0.45rem;
  font-size: 1.08rem;
}

.meta-list {
  display: grid;
  gap: 0.35rem;
  margin: 0.7rem 0 1rem;
  color: var(--muted);
  font-size: 0.92rem;
}

.meta-list li {
  padding-left: 0.9rem;
  position: relative;
}

.meta-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.55em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--brand-2);
}

.feature-card p,
.scene-card p,
.faq-item p,
.step-card p,
.compat-item p,
.docs-panel p,
.download-card p {
  margin: 0;
  color: var(--muted);
}

.inline-img {
  margin-top: 1.2rem;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  width: 100%;
  max-height: 280px;
  object-fit: cover;
}

.how-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.flow-panel,
.preview-panel { padding: 1.2rem; }

.flow-list {
  display: grid;
  gap: 0.9rem;
}

.flow-list li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.8rem;
  align-items: start;
}

.flow-num {
  width: 34px;
  height: 34px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  color: #fff;
  font-weight: 800;
}

.flow-list h3 {
  margin: 0 0 0.2rem;
  font-size: 1rem;
}

.flow-list p {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.preview-panel img {
  width: 100%;
  height: 180px;
  object-fit: cover;
  border-radius: 14px;
  margin-bottom: 0.9rem;
}

.code-box {
  margin: 0;
  padding: 1rem;
  border-radius: 14px;
  background: #0b1220;
  color: #dbeafe;
  font-size: 0.84rem;
  overflow: auto;
  line-height: 1.5;
}

.ability-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 1rem;
}

.ability-row span {
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  background: #fff;
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.88rem;
  box-shadow: var(--shadow);
}

.compat-item {
  display: grid;
  gap: 0.2rem;
}

.steps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

.hint-box {
  margin-top: 1rem;
  padding: 1rem 1.1rem;
  border-radius: var(--radius);
  background: #fff7ed;
  border: 1px solid #fed7aa;
  color: #9a3412;
}

.hint-box strong { display: block; margin-bottom: 0.35rem; }
.hint-box p { margin: 0; }

.page-hero {
  padding: 2.6rem 0 1rem;
}

.page-hero h1 {
  margin: 0.35rem 0 0.7rem;
  font-size: clamp(1.8rem, 3vw, 2.5rem);
  letter-spacing: -0.02em;
}

.page-hero p {
  margin: 0;
  color: var(--muted);
  max-width: 62ch;
}

.download-list {
  display: grid;
  gap: 1rem;
}

.download-card {
  display: grid;
  grid-template-columns: 1.3fr 1fr auto;
  gap: 1rem;
  align-items: center;
  padding: 1.2rem;
}

.cta-band {
  margin: 1rem 0 3rem;
  padding: 2rem;
  border-radius: 28px;
  background:
    linear-gradient(135deg, rgba(37,99,235,0.95), rgba(14,165,233,0.92)),
    #1d4ed8;
  color: #fff;
  box-shadow: 0 24px 48px rgba(37, 99, 235, 0.25);
  text-align: center;
}

.cta-band h2 {
  margin: 0 0 0.45rem;
  font-size: clamp(1.5rem, 2.5vw, 2rem);
}

.cta-band p {
  margin: 0 0 1.1rem;
  opacity: 0.92;
}

.cta-band .cta-actions {
  justify-content: center;
}

.cta-band .btn-primary {
  background: #fff;
  color: var(--brand-ink);
  box-shadow: none;
}

.cta-band .btn-secondary {
  background: transparent;
  color: #fff;
  border-color: rgba(255,255,255,0.4);
}

.site-footer {
  padding: 2.5rem 0 1.5rem;
  background: #0f172a;
  color: #cbd5e1;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr repeat(4, 1fr);
  gap: 1.2rem;
}

.site-footer h3,
.site-footer h4 {
  margin: 0 0 0.7rem;
  color: #fff;
}

.site-footer p {
  margin: 0;
  color: #94a3b8;
  font-size: 0.92rem;
}

.site-footer ul {
  display: grid;
  gap: 0.4rem;
}

.site-footer a:hover { color: #fff; }

.footer-bottom {
  margin-top: 1.6rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(148, 163, 184, 0.25);
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  font-size: 0.88rem;
  color: #94a3b8;
}

.tutorial-layout {
  display: grid;
  gap: 1rem;
}

@media (max-width: 980px) {
  .hero-grid,
  .how-grid,
  .download-card {
    grid-template-columns: 1fr;
  }
  .platform-grid,
  .feature-grid,
  .recommend-grid,
  .scene-grid,
  .compat-grid,
  .steps,
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
  .nav-links { display: none; }
}

@media (max-width: 640px) {
  .trust-row,
  .platform-grid,
  .feature-grid,
  .recommend-grid,
  .scene-grid,
  .compat-grid,
  .faq-grid,
  .steps,
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .cta-panel { min-height: auto; }
}