:root {
  --bg: #f4f8fc;
  --ink: #12263a;
  --muted: #5a7188;
  --line: #c9dae8;
  --cloud: #ffffff;
  --sky: #2f80ed;
  --cyan: #22b8cf;
  --navy: #1b3a57;
  --soft: #e8f2fb;
  --ok: #12b886;
  --warn: #f59f00;
  --shadow: 0 14px 36px rgba(27, 58, 87, 0.1);
  --radius: 16px;
  --font-display: "Segoe UI Variable Display", "Bahnschrift", "PingFang SC", "Microsoft YaHei UI", sans-serif;
  --font-body: "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-body);
  background:
    radial-gradient(circle at 12% 0%, rgba(47, 128, 237, 0.12), transparent 28%),
    radial-gradient(circle at 88% 8%, rgba(34, 184, 207, 0.12), transparent 30%),
    linear-gradient(180deg, #eef5fb 0%, var(--bg) 40%, #edf3f9 100%);
  line-height: 1.65;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button { font: inherit; cursor: pointer; }

.container {
  width: min(1140px, calc(100% - 2rem));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(244, 248, 252, 0.88);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(12px);
}

.nav {
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  font-family: var(--font-display);
  font-weight: 700;
}

.logo-mark {
  width: 38px;
  height: 38px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  color: #fff;
  background: linear-gradient(135deg, var(--sky), var(--cyan));
  box-shadow: 0 8px 18px rgba(47, 128, 237, 0.28);
}

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

.nav-links {
  display: flex;
  gap: 0.2rem;
  flex-wrap: wrap;
}

.nav-links a {
  padding: 0.45rem 0.75rem;
  border-radius: 999px;
  color: var(--muted);
  font-size: 0.95rem;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--navy);
  background: var(--soft);
}

.lang-switch {
  display: flex;
  gap: 0.3rem;
  padding: 0.2rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
}

.lang-switch button {
  border: 0;
  background: transparent;
  color: var(--muted);
  padding: 0.3rem 0.65rem;
  border-radius: 999px;
}

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

.hero {
  padding: 3.2rem 0 2.4rem;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 10% 5% auto;
  height: 280px;
  background:
    linear-gradient(90deg, transparent, rgba(47, 128, 237, 0.12), transparent),
    radial-gradient(circle at 30% 50%, rgba(34, 184, 207, 0.16), transparent 40%),
    radial-gradient(circle at 70% 50%, rgba(47, 128, 237, 0.14), transparent 42%);
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 2rem;
  align-items: center;
  position: relative;
}

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

.tag {
  padding: 0.28rem 0.7rem;
  border-radius: 999px;
  border: 1px solid #b7d4f2;
  background: #fff;
  color: var(--sky);
  font-size: 0.82rem;
  font-weight: 600;
}

.hero h1 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3rem);
  line-height: 1.18;
  color: var(--navy);
}

.hero h1 em {
  font-style: normal;
  background: linear-gradient(90deg, var(--sky), var(--cyan));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-lead {
  margin: 1rem 0 1.4rem;
  color: var(--muted);
  font-size: 1.05rem;
  max-width: 36rem;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.65rem 1.15rem;
  border-radius: 12px;
  border: 1px solid transparent;
  font-weight: 650;
  transition: transform .2s ease, box-shadow .2s ease;
}

.btn:hover { transform: translateY(-2px); }

.btn-primary {
  color: #fff;
  background: linear-gradient(135deg, var(--sky), #1f6fd8);
  box-shadow: 0 10px 22px rgba(47, 128, 237, 0.28);
}

.btn-secondary {
  color: var(--navy);
  background: #fff;
  border-color: var(--line);
}

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

.trust-item {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 0.85rem 0.9rem;
  box-shadow: var(--shadow);
}

.trust-item strong {
  display: block;
  font-size: 1.05rem;
  color: var(--navy);
}

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

.arch-stage {
  position: relative;
  min-height: 390px;
  border-radius: 24px;
  border: 1px solid #bfd4ea;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.95), rgba(236, 245, 252, 0.95)),
    repeating-linear-gradient(90deg, rgba(47, 128, 237, 0.05) 0 1px, transparent 1px 28px),
    repeating-linear-gradient(0deg, rgba(47, 128, 237, 0.05) 0 1px, transparent 1px 28px);
  box-shadow: var(--shadow);
  overflow: hidden;
  padding: 1.2rem;
}

.arch-stage img {
  width: 100%;
  height: 210px;
  object-fit: cover;
  border-radius: 16px;
  border: 1px solid #d3e4f4;
}

.cloud-nodes {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.node {
  position: absolute;
  min-width: 88px;
  padding: 0.45rem 0.65rem;
  border-radius: 999px;
  background: #fff;
  border: 1px solid #b7d4f2;
  color: var(--navy);
  font-size: 0.78rem;
  font-weight: 700;
  box-shadow: 0 8px 16px rgba(27, 58, 87, 0.08);
  text-align: center;
}

.node-a { left: 8%; top: 62%; }
.node-b { left: 38%; top: 74%; }
.node-c { right: 8%; top: 62%; }
.node-d { left: 24%; top: 18%; }
.node-e { right: 18%; top: 18%; }

.link-line {
  position: absolute;
  height: 2px;
  background: linear-gradient(90deg, rgba(47, 128, 237, 0.15), rgba(34, 184, 207, 0.7), rgba(47, 128, 237, 0.15));
}

.line-1 { left: 18%; top: 68%; width: 28%; transform: rotate(8deg); }
.line-2 { right: 18%; top: 68%; width: 28%; transform: rotate(-8deg); }
.line-3 { left: 30%; top: 40%; width: 18%; transform: rotate(-48deg); }
.line-4 { right: 28%; top: 40%; width: 18%; transform: rotate(48deg); }

.section { padding: 3.2rem 0; }

.section-head {
  margin-bottom: 1.5rem;
  max-width: 42rem;
}

.section-kicker {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--sky);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 0.5rem;
}

.section-kicker::before {
  content: "";
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--sky), var(--cyan));
  box-shadow: 0 0 0 4px rgba(47, 128, 237, 0.15);
}

.section-head h2 {
  margin: 0 0 0.55rem;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 2.6vw, 2.1rem);
  color: var(--navy);
}

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

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

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

.compat-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

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

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

.platform-card h3,
.feature-card h3,
.recommend-card h3,
.step-card h3,
.scene-card h3,
.faq-item h3,
.compat-item h3,
.docs-panel h3,
.download-card h3 {
  margin: 0 0 0.45rem;
  font-family: var(--font-display);
  color: var(--navy);
}

.platform-card p,
.feature-card p,
.recommend-card p,
.step-card p,
.scene-card p,
.faq-item p,
.compat-item p,
.docs-panel p,
.download-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.os-badge,
.badge,
.step-label,
.feature-index,
.compat-dot,
.status {
  display: inline-flex;
  align-items: center;
  padding: 0.22rem 0.6rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.03em;
}

.os-badge,
.badge {
  color: var(--sky);
  background: var(--soft);
  border: 1px solid #c7def5;
  margin-bottom: 0.65rem;
}

.feature-index {
  color: #fff;
  background: linear-gradient(135deg, var(--sky), var(--cyan));
  margin-bottom: 0.7rem;
}

.meta-list {
  list-style: none;
  margin: 0.7rem 0 1rem;
  padding: 0;
  display: grid;
  gap: 0.35rem;
}

.meta-list li {
  color: var(--muted);
  font-size: 0.92rem;
  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(--cyan);
}

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

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

.flow-list {
  list-style: none;
  margin: 0;
  padding: 0;
  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;
  color: #fff;
  font-weight: 700;
  background: linear-gradient(135deg, var(--sky), var(--cyan));
}

.flow-list h3 {
  margin: 0 0 0.25rem;
  font-size: 1rem;
  color: var(--navy);
}

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

.preview-panel img {
  width: 100%;
  height: 210px;
  object-fit: cover;
  border-radius: 12px;
  border: 1px solid var(--line);
  margin-bottom: 0.85rem;
}

.code-box {
  margin: 0;
  padding: 0.95rem 1rem;
  border-radius: 12px;
  background: #12263a;
  color: #d7ebff;
  font-size: 0.84rem;
  overflow: auto;
  line-height: 1.55;
}

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

.ability-row span {
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  background: #fff;
  border: 1px solid var(--line);
  color: var(--navy);
  font-size: 0.88rem;
  font-weight: 600;
}

.compat-item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.85rem;
  align-items: start;
}

.compat-dot {
  color: #fff;
  background: linear-gradient(135deg, var(--sky), var(--cyan));
}

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

.step-label {
  color: var(--cyan);
  background: #e7f9fc;
  border: 1px solid #b7ebf2;
  margin-bottom: 0.65rem;
}

.hint-box {
  margin-top: 1rem;
  padding: 1rem 1.15rem;
  border-left: 4px solid var(--warn);
}

.hint-box strong {
  display: block;
  margin-bottom: 0.3rem;
  color: var(--navy);
}

.hint-box p {
  margin: 0;
  color: var(--muted);
}

.inline-img {
  margin-top: 1.2rem;
  width: 100%;
  max-height: 280px;
  object-fit: cover;
  border-radius: 16px;
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}

.cta-band {
  margin: 0.5rem 0 3rem;
  padding: 2rem;
  border-radius: 22px;
  border: 1px solid #b7d4f2;
  background:
    radial-gradient(circle at 15% 20%, rgba(34, 184, 207, 0.16), transparent 35%),
    radial-gradient(circle at 85% 80%, rgba(47, 128, 237, 0.18), transparent 38%),
    linear-gradient(135deg, #ffffff, #eaf3fb);
  box-shadow: var(--shadow);
  text-align: center;
}

.cta-band h2 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  color: var(--navy);
}

.cta-band p {
  margin: 0 0 1.1rem;
  color: var(--muted);
}

.cta-actions {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.site-footer {
  background: #12263a;
  color: #d5e4f2;
  padding: 2.6rem 0 1.4rem;
}

.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;
  font-family: var(--font-display);
}

.site-footer p,
.site-footer li {
  color: #9eb4c9;
  font-size: 0.92rem;
}

.site-footer ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.35rem;
}

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

.footer-bottom {
  margin-top: 1.6rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(158, 180, 201, 0.25);
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  font-size: 0.88rem;
  color: #8aa0b6;
}

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

.page-hero h1 {
  margin: 0.4rem 0 0.7rem;
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 3.2vw, 2.5rem);
  color: var(--navy);
}

.page-hero p {
  margin: 0;
  color: var(--muted);
  max-width: 42rem;
}

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

.download-card {
  display: grid;
  grid-template-columns: 1.3fr 1fr auto;
  gap: 1rem;
  align-items: center;
  padding: 1.15rem 1.25rem;
}

.status {
  color: var(--ok);
  background: #e6fcf5;
  border: 1px solid #b2f2bb;
  margin-bottom: 0.45rem;
}

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

@media (max-width: 960px) {
  .hero-grid,
  .how-grid,
  .download-card,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .platform-grid,
  .feature-grid,
  .recommend-grid,
  .scene-grid,
  .faq-grid,
  .steps,
  .compat-grid {
    grid-template-columns: 1fr 1fr;
  }

  .nav-links { display: none; }
  .arch-stage { min-height: 340px; }
}

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

  .cta-band { padding: 1.4rem; }
  .download-card { grid-template-columns: 1fr; }
}