:root {
  --bg: #f3f6fa;
  --bg-soft: #ffffff;
  --ink: #142033;
  --muted: #5b6b80;
  --line: #d7e0ec;
  --brand: #0b6bcb;
  --brand-2: #0a8f7a;
  --accent: #e85d04;
  --ok: #1f9d55;
  --shadow: 0 10px 30px rgba(20, 32, 51, 0.08);
  --radius: 16px;
  --font-display: "Candara", "Segoe UI Variable", "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, #eaf1f8 0, var(--bg) 220px),
    var(--bg);
  line-height: 1.65;
}

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

.container {
  width: min(1120px, calc(100% - 2rem));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.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;
  font-size: 1.15rem;
}

.logo-mark {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  color: #fff;
  background: linear-gradient(145deg, var(--brand), var(--brand-2));
  box-shadow: 0 8px 18px rgba(11, 107, 203, 0.25);
  font-size: 0.78rem;
}

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

.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem 1.1rem;
  color: var(--muted);
}

.nav-links a:hover,
.nav-links a.active { color: var(--brand); font-weight: 600; }

.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);
  border-radius: 999px;
  padding: 0.3rem 0.7rem;
}

.lang-switch button.active {
  background: #eaf3ff;
  color: var(--brand);
}

.hero {
  padding: 3.4rem 0 2.4rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 2rem;
  align-items: center;
}

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

.tag {
  display: inline-flex;
  padding: 0.28rem 0.7rem;
  border-radius: 999px;
  background: #fff;
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.84rem;
}

.hero h1 {
  margin: 0 0 0.9rem;
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3.1rem);
  line-height: 1.18;
  max-width: 14ch;
}

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

.hero-lead {
  margin: 0 0 1.4rem;
  color: var(--muted);
  max-width: 40rem;
  font-size: 1.05rem;
}

.hero-actions,
.cta-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: 46px;
  padding: 0.7rem 1.25rem;
  border-radius: 12px;
  border: 1px solid transparent;
  font-family: var(--font-display);
  font-weight: 700;
  transition: transform 0.18s ease, box-shadow 0.18s ease, background 0.18s ease;
}

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

.btn-primary {
  background: linear-gradient(180deg, #1a7de0, var(--brand));
  color: #fff;
  box-shadow: 0 10px 22px rgba(11, 107, 203, 0.28);
}

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

.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 0.95rem;
  box-shadow: var(--shadow);
}

.trust-item strong {
  display: block;
  font-family: var(--font-display);
  font-size: 1.1rem;
}

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

.hero-panel {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: 1rem;
  box-shadow: var(--shadow);
  position: relative;
}

.hero-panel::before {
  content: "Official Download Portal";
  position: absolute;
  top: 1.1rem;
  left: 1.1rem;
  z-index: 2;
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.25rem 0.7rem;
  font-size: 0.78rem;
  color: var(--brand);
  font-family: var(--font-display);
}

.hero-panel img {
  border-radius: 16px;
  aspect-ratio: 4/3;
  object-fit: cover;
}

.dl-chip-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.55rem;
  margin-top: 0.8rem;
}

.dl-chip {
  text-align: center;
  padding: 0.55rem 0.4rem;
  border-radius: 12px;
  background: #f5f8fc;
  border: 1px solid var(--line);
  font-size: 0.82rem;
  color: var(--muted);
}

.section { padding: 3.4rem 0; }

.section-head {
  margin-bottom: 1.5rem;
  max-width: 44rem;
}

.section-kicker {
  display: inline-block;
  margin-bottom: 0.45rem;
  color: var(--brand);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.9rem;
  letter-spacing: 0.04em;
}

.section-head h2 {
  margin: 0 0 0.55rem;
  font-family: var(--font-display);
  font-size: clamp(1.55rem, 2.8vw, 2.1rem);
  line-height: 1.25;
}

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

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

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

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

.platform-card,
.feature-card,
.recommend-card,
.scene-card,
.faq-item,
.step-card,
.compat-item,
.hint-box,
.docs-panel {
  padding: 1.2rem 1.25rem;
}

.platform-card h3,
.feature-card h3,
.recommend-card h3,
.scene-card h3,
.faq-item h3,
.step-card h3,
.docs-panel h3 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-size: 1.12rem;
}

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

.meta-list {
  list-style: none;
  margin: 0.8rem 0 1rem;
  padding: 0;
  display: grid;
  gap: 0.4rem;
  color: var(--muted);
  font-size: 0.93rem;
}

.meta-list li {
  display: flex;
  gap: 0.45rem;
}

.meta-list li::before {
  content: "•";
  color: var(--brand);
  font-weight: 700;
}

.os-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 12px;
  margin-bottom: 0.7rem;
  background: #eaf3ff;
  color: var(--brand);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.78rem;
}

.feature-card {
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.feature-card:hover {
  border-color: #b7cff0;
  transform: translateY(-3px);
}

.feature-index {
  width: 34px;
  height: 34px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  margin-bottom: 0.75rem;
  background: #edf8f4;
  color: var(--brand-2);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.85rem;
}

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

.flow-panel,
.preview-panel {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 1.25rem;
  box-shadow: var(--shadow);
}

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

.flow-list li {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: 0.8rem;
}

.flow-num {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: linear-gradient(145deg, #1a7de0, var(--brand-2));
  color: #fff;
  font-family: var(--font-display);
  font-weight: 700;
}

.flow-list h3 {
  margin: 0 0 0.25rem;
  font-size: 1.02rem;
  font-family: var(--font-display);
}

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

.preview-panel img {
  border-radius: 14px;
  border: 1px solid var(--line);
  margin-bottom: 0.9rem;
}

.code-box {
  margin: 0;
  padding: 0.95rem 1rem;
  border-radius: 12px;
  background: #152033;
  color: #d7f3ec;
  font-size: 0.84rem;
  overflow-x: auto;
  line-height: 1.55;
}

.ability-row {
  margin-top: 1rem;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.75rem;
}

.ability-row span {
  display: block;
  background: #fff;
  border: 1px dashed #c8d5e6;
  border-radius: 12px;
  padding: 0.8rem 0.9rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.compat-item {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 0.85rem;
  align-items: start;
}

.compat-dot {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  background: #fff4ec;
  color: var(--accent);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.75rem;
}

.recommend-card .badge {
  display: inline-flex;
  margin-bottom: 0.65rem;
  padding: 0.22rem 0.65rem;
  border-radius: 999px;
  background: #e8f8ef;
  color: var(--ok);
  font-size: 0.8rem;
  font-weight: 700;
}

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

.step-label {
  display: inline-block;
  margin-bottom: 0.55rem;
  color: var(--brand);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.86rem;
}

.hint-box {
  border-color: #f0c9ad;
  background: #fff8f3;
}

.hint-box strong {
  display: block;
  margin-bottom: 0.4rem;
  color: var(--accent);
  font-family: var(--font-display);
}

.scene-card { min-height: 150px; }

.cta-band {
  margin: 0.5rem 0 3rem;
  padding: 2.2rem;
  border-radius: 22px;
  text-align: center;
  background: linear-gradient(135deg, #0b6bcb, #0a8f7a);
  color: #fff;
  box-shadow: 0 16px 36px rgba(11, 107, 203, 0.25);
}

.cta-band h2 {
  margin: 0 0 0.55rem;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 2.8vw, 2rem);
}

.cta-band p {
  margin: 0 auto 1.2rem;
  max-width: 34rem;
  color: rgba(255, 255, 255, 0.9);
}

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

.cta-band .btn-secondary {
  background: transparent;
  border-color: rgba(255, 255, 255, 0.45);
  color: #fff;
}

.cta-actions { justify-content: center; margin-bottom: 0; }

.site-footer {
  background: #101a29;
  color: #d5deea;
  padding: 2.8rem 0 1.3rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.35fr repeat(4, 1fr);
  gap: 1.1rem;
  margin-bottom: 1.5rem;
}

.site-footer h3,
.site-footer h4 {
  margin: 0 0 0.75rem;
  font-family: var(--font-display);
  color: #fff;
}

.site-footer p,
.site-footer li,
.site-footer a { color: #aeb9c9; }

.site-footer ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.4rem;
}

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

.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  padding-top: 1rem;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  color: #8e9aab;
  font-size: 0.9rem;
}

.page-hero {
  padding: 2.8rem 0 1rem;
}

.page-hero h1 {
  margin: 0 0 0.7rem;
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3.2vw, 2.4rem);
}

.page-hero p {
  margin: 0;
  color: var(--muted);
  max-width: 46rem;
}

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

.download-card {
  display: grid;
  grid-template-columns: 1.25fr 1fr auto;
  gap: 1rem;
  align-items: center;
  padding: 1.2rem 1.3rem;
}

.download-card h3 {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
}

.status {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--ok);
  font-weight: 700;
  font-size: 0.88rem;
}

.status::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--ok);
}

.inline-img {
  border-radius: 16px;
  border: 1px solid var(--line);
  margin: 1rem 0;
  box-shadow: var(--shadow);
}

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

@media (max-width: 980px) {
  .hero-grid,
  .how-grid,
  .download-card,
  .footer-grid {
    grid-template-columns: 1fr;
  }

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

  .nav-links { display: none; }
}

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

  .cta-band { padding: 1.5rem; }
}