:root {
  --bg: #f4f7fb;
  --ink: #142033;
  --muted: #5d6b82;
  --line: #d7e0ee;
  --panel: #ffffff;
  --brand: #1f6fff;
  --brand-2: #0ea5a5;
  --soft: #eaf1ff;
  --ok: #0f9f6e;
  --shadow: 0 14px 34px rgba(20, 32, 51, 0.08);
  --radius: 18px;
  --font-display: "Segoe UI Variable Display", "Avenir Next", "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:
    linear-gradient(180deg, #eef4ff 0%, var(--bg) 28%, #f7f9fc 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(1160px, calc(100% - 2rem));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(255, 255, 255, 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(--brand), var(--brand-2));
  box-shadow: 0 8px 18px rgba(31, 111, 255, 0.28);
}

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

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

.nav-links a {
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  color: var(--muted);
  font-size: 0.94rem;
}

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

.lang-switch {
  display: flex;
  gap: 0.25rem;
  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(--brand);
  color: #fff;
  font-weight: 700;
}

.hero {
  padding: 3.2rem 0 2.2rem;
}

.split {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 1.6rem;
  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;
  border: 1px solid #c9dbff;
  background: #f3f7ff;
  color: var(--brand);
  font-size: 0.82rem;
  font-weight: 700;
}

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

.hero h1 em {
  font-style: normal;
  color: var(--brand);
}

.hero-lead {
  margin: 1rem 0 1.35rem;
  color: var(--muted);
  font-size: 1.04rem;
  max-width: 36rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1.3rem;
}

.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: 700;
  transition: transform .2s ease, box-shadow .2s ease;
}

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

.btn-primary {
  color: #fff;
  background: linear-gradient(135deg, var(--brand), #3b82f6);
  box-shadow: 0 10px 22px rgba(31, 111, 255, 0.25);
}

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

.trust-row {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.7rem;
}

.trust-item {
  background: var(--panel);
  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;
}

.trust-item span {
  color: var(--muted);
  font-size: 0.85rem;
}

.hero-visual {
  position: relative;
  min-height: 420px;
  border-radius: 28px;
  border: 1px solid var(--line);
  background:
    radial-gradient(circle at 20% 20%, rgba(31, 111, 255, 0.12), transparent 40%),
    radial-gradient(circle at 80% 70%, rgba(14, 165, 165, 0.12), transparent 42%),
    #fff;
  box-shadow: var(--shadow);
  overflow: hidden;
  padding: 1.2rem;
  display: grid;
  align-content: center;
  gap: 0.9rem;
}

.hero-visual img {
  width: 100%;
  height: 250px;
  object-fit: cover;
  border-radius: 16px;
  border: 1px solid var(--line);
}

.visual-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.7rem;
}

.visual-card div {
  background: var(--soft);
  border: 1px solid #d7e4ff;
  border-radius: 12px;
  padding: 0.75rem;
}

.visual-card strong {
  display: block;
  font-size: 0.9rem;
}

.visual-card span {
  color: var(--muted);
  font-size: 0.8rem;
}

.section { padding: 3rem 0; }

.section-head {
  margin-bottom: 1.35rem;
  max-width: 42rem;
}

.section-kicker {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--brand);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: 0.5rem;
}

.section-kicker::before {
  content: "";
  width: 10px;
  height: 10px;
  border-radius: 3px;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
}

.section-head h2 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 2.6vw, 2.1rem);
}

.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,
.feature-row {
  background: var(--panel);
  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:hover,
.recommend-card:hover,
.feature-row:hover {
  border-color: #b8cdff;
  transform: translateY(-2px);
  transition: transform .2s ease, border-color .2s ease;
}

.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,
.feature-row h3 {
  margin: 0 0 0.4rem;
  font-family: var(--font-display);
}

.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,
.feature-row p {
  margin: 0;
  color: var(--muted);
  font-size: 0.94rem;
}

.feature-stack {
  display: grid;
  gap: 1rem;
}

.feature-row {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 0;
  overflow: hidden;
  min-height: 210px;
}

.feature-row.reverse .feature-copy { order: 2; }
.feature-row.reverse .feature-media { order: 1; }

.feature-copy {
  padding: 1.4rem 1.5rem;
  display: grid;
  align-content: center;
  gap: 0.55rem;
}

.feature-media {
  background:
    linear-gradient(160deg, #eef4ff, #f3fffc);
  border-left: 1px solid var(--line);
  display: grid;
  place-items: center;
  padding: 1rem;
}

.feature-row.reverse .feature-media {
  border-left: 0;
  border-right: 1px solid var(--line);
}

.feature-media img {
  width: 100%;
  height: 170px;
  object-fit: cover;
  border-radius: 14px;
  border: 1px solid var(--line);
}

.feature-index,
.os-badge,
.badge,
.step-label,
.compat-dot,
.status {
  display: inline-flex;
  align-items: center;
  padding: 0.22rem 0.6rem;
  border-radius: 999px;
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.03em;
}

.os-badge,
.badge,
.feature-index {
  color: var(--brand);
  background: var(--soft);
  border: 1px solid #cfe0ff;
  margin-bottom: 0.55rem;
  width: fit-content;
}

.meta-list {
  list-style: none;
  margin: 0.65rem 0 1rem;
  padding: 0;
  display: grid;
  gap: 0.32rem;
}

.meta-list li {
  color: var(--muted);
  font-size: 0.9rem;
  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);
}

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

.flow-panel,
.preview-panel {
  padding: 1.15rem;
}

.flow-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.85rem;
}

.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: 800;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
}

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

.flow-list p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.preview-panel img {
  width: 100%;
  height: 205px;
  object-fit: cover;
  border-radius: 14px;
  border: 1px solid var(--line);
  margin-bottom: 0.85rem;
}

.code-box {
  margin: 0;
  padding: 0.95rem 1rem;
  border-radius: 12px;
  background: #132033;
  color: #d7e8ff;
  font-size: 0.84rem;
  overflow: auto;
  line-height: 1.55;
}

.ability-row {
  margin-top: 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.ability-row span {
  padding: 0.42rem 0.78rem;
  border-radius: 999px;
  background: #fff;
  border: 1px solid var(--line);
  color: var(--ink);
  font-size: 0.86rem;
  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(--brand), var(--brand-2));
}

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

.step-label {
  color: var(--brand-2);
  background: #e9fbf8;
  border: 1px solid #b9ebe3;
  margin-bottom: 0.6rem;
  width: fit-content;
}

.hint-box {
  margin-top: 1rem;
  padding: 1rem 1.1rem;
  border-left: 4px solid var(--brand);
}

.hint-box strong {
  display: block;
  margin-bottom: 0.25rem;
}

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

.inline-img {
  margin-top: 1.15rem;
  width: 100%;
  max-height: 280px;
  object-fit: cover;
  border-radius: 16px;
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}

.cta-band {
  margin: 0.4rem 0 2.8rem;
  padding: 2rem;
  border-radius: 24px;
  border: 1px solid #c9dbff;
  background:
    radial-gradient(circle at 15% 20%, rgba(31, 111, 255, 0.12), transparent 40%),
    radial-gradient(circle at 85% 80%, rgba(14, 165, 165, 0.12), transparent 42%),
    #fff;
  box-shadow: var(--shadow);
  text-align: center;
}

.cta-band h2 {
  margin: 0 0 0.45rem;
  font-family: var(--font-display);
}

.cta-band p {
  margin: 0 0 1.05rem;
  color: var(--muted);
}

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

.site-footer {
  background: #101a2b;
  color: #c7d3e8;
  padding: 2.5rem 0 1.3rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr repeat(4, 1fr);
  gap: 1.15rem;
}

.site-footer h3,
.site-footer h4 {
  margin: 0 0 0.65rem;
  color: #fff;
  font-family: var(--font-display);
}

.site-footer p,
.site-footer li {
  color: #91a1bb;
  font-size: 0.9rem;
}

.site-footer ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.32rem;
}

.site-footer a:hover { color: #9ec1ff; }

.footer-bottom {
  margin-top: 1.5rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(145, 161, 187, 0.22);
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  font-size: 0.86rem;
  color: #7d8eaa;
}

.page-hero {
  padding: 2.5rem 0 1rem;
}

.page-hero h1 {
  margin: 0.35rem 0 0.65rem;
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3.1vw, 2.45rem);
}

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

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

.download-card {
  display: grid;
  grid-template-columns: 1.3fr 1fr auto;
  gap: 1rem;
  align-items: center;
  padding: 1.1rem 1.2rem;
}

.status {
  color: var(--ok);
  background: #e9fbf3;
  border: 1px solid #b7ecd5;
  margin-bottom: 0.4rem;
  width: fit-content;
}

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

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

  .feature-row.reverse .feature-copy,
  .feature-row.reverse .feature-media { order: initial; }

  .feature-media,
  .feature-row.reverse .feature-media {
    border: 0;
    border-top: 1px solid var(--line);
  }

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

  .nav-links { display: none; }
  .hero-visual { min-height: auto; }
}

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

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