:root {
  --bg: #0a0c10;
  --bg-2: #12161d;
  --surface: rgba(255, 255, 255, 0.04);
  --surface-strong: rgba(255, 255, 255, 0.08);
  --ink: #f3f5f7;
  --muted: #9aa3ad;
  --line: rgba(255, 255, 255, 0.12);
  --metal-1: #e8eef5;
  --metal-2: #8b97a6;
  --metal-3: #c5d0dc;
  --accent: #7dd3fc;
  --accent-2: #a5b4fc;
  --ok: #6ee7b7;
  --shadow: 0 20px 50px rgba(0, 0, 0, 0.45);
  --radius: 20px;
  --radius-sm: 14px;
  --max: 1140px;
  --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 480px at 12% -8%, rgba(165, 180, 252, 0.16), transparent 55%),
    radial-gradient(700px 420px at 88% 0%, rgba(125, 211, 252, 0.12), transparent 50%),
    linear-gradient(180deg, #0b0e14 0%, #0a0c10 40%, #10151c 100%);
  line-height: 1.65;
}

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; }

.metal-text {
  background: linear-gradient(120deg, #ffffff 0%, #b8c2ce 28%, #f5f7fa 52%, #8e9aab 78%, #e7eef6 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(16px);
  background: rgba(10, 12, 16, 0.78);
  border-bottom: 1px solid var(--line);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 74px;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.logo-mark {
  width: 40px;
  height: 40px;
  border-radius: 13px;
  display: grid;
  place-items: center;
  font-size: 0.85rem;
  color: #0b0e14;
  background: linear-gradient(145deg, #f8fafc 0%, #aeb8c6 40%, #f1f5f9 60%, #7f8b99 100%);
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.75),
    0 10px 24px rgba(148, 163, 184, 0.25);
}

.logo-text span {
  background: linear-gradient(120deg, #dbeafe, #a5b4fc);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.nav-links {
  display: flex;
  gap: 0.3rem;
  flex-wrap: wrap;
}

.nav-links a {
  padding: 0.45rem 0.85rem;
  border-radius: 999px;
  color: var(--muted);
  font-size: 0.94rem;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--ink);
  background: var(--surface-strong);
  border: 1px solid var(--line);
}

.lang-switch {
  display: inline-flex;
  padding: 0.2rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255,255,255,0.03);
}

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

.lang-switch button.active {
  color: #0b0e14;
  background: linear-gradient(135deg, #f8fafc, #9aa8b8);
}

.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, filter .2s ease;
}

.btn:hover { transform: translateY(-1px); filter: brightness(1.05); }

.btn-primary {
  color: #0b0e14;
  background: linear-gradient(135deg, #f8fafc 0%, #c5d0dc 35%, #f1f5f9 55%, #8b97a6 100%);
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.7),
    0 14px 30px rgba(148, 163, 184, 0.22);
}

.btn-secondary {
  color: var(--ink);
  background: rgba(255,255,255,0.04);
  border-color: rgba(255,255,255,0.18);
}

.hero {
  padding: 3.4rem 0 2.2rem;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 8% 42% auto auto;
  width: 420px;
  height: 420px;
  border-radius: 50%;
  background:
    radial-gradient(circle at 30% 30%, rgba(255,255,255,0.55), transparent 28%),
    radial-gradient(circle at 70% 65%, rgba(125,211,252,0.35), transparent 40%),
    linear-gradient(145deg, #dbe3ec, #6b7787 45%, #eef2f7 70%, #8d98a7);
  filter: blur(2px);
  opacity: 0.55;
  animation: metal-float 8s ease-in-out infinite;
  pointer-events: none;
}

@keyframes metal-float {
  0%, 100% { transform: translateY(0) scale(1); }
  50% { transform: translateY(-14px) scale(1.03); }
}

.hero-grid {
  position: relative;
  z-index: 1;
  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;
  font-size: 0.82rem;
  font-weight: 700;
  color: #dbeafe;
  background: rgba(125, 211, 252, 0.1);
  border: 1px solid rgba(125, 211, 252, 0.28);
}

.hero h1 {
  margin: 0 0 0.9rem;
  font-size: clamp(2rem, 4vw, 3.2rem);
  line-height: 1.14;
  letter-spacing: -0.03em;
}

.hero h1 em {
  font-style: normal;
  background: linear-gradient(120deg, #ffffff, #9fb0c3 40%, #e8eef6 70%, #7dd3fc);
  -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: linear-gradient(180deg, rgba(255,255,255,0.08), rgba(255,255,255,0.03));
  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;
}

.metal-stage {
  position: relative;
  min-height: 430px;
  border-radius: 28px;
  padding: 1.2rem;
  overflow: hidden;
  background:
    linear-gradient(160deg, rgba(255,255,255,0.12), rgba(255,255,255,0.02)),
    #151a22;
  border: 1px solid rgba(255,255,255,0.16);
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.2),
    var(--shadow);
}

.metal-blob {
  position: absolute;
  width: 220px;
  height: 220px;
  border-radius: 46% 54% 48% 52%;
  background:
    radial-gradient(circle at 28% 28%, rgba(255,255,255,0.85), transparent 26%),
    linear-gradient(145deg, #f8fafc, #8b97a6 40%, #e2e8f0 62%, #64748b);
  filter: blur(0.2px);
  opacity: 0.9;
  animation: blob-morph 10s ease-in-out infinite;
}

.metal-blob.b1 { top: 12%; left: 10%; }
.metal-blob.b2 {
  width: 160px;
  height: 160px;
  right: 8%;
  bottom: 18%;
  animation-delay: -3s;
  opacity: 0.65;
}

@keyframes blob-morph {
  0%, 100% { border-radius: 46% 54% 48% 52%; transform: translateY(0) rotate(0deg); }
  50% { border-radius: 54% 46% 52% 48%; transform: translateY(-10px) rotate(8deg); }
}

.metal-stage img {
  position: relative;
  z-index: 1;
  width: 100%;
  height: 260px;
  object-fit: cover;
  border-radius: 18px;
  border: 1px solid rgba(255,255,255,0.18);
  margin-top: 2.4rem;
}

.metal-label {
  position: relative;
  z-index: 1;
  margin-top: 1rem;
  font-size: 0.78rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: #cbd5e1;
}

.section { padding: 3.2rem 0; }

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

.section-kicker {
  display: inline-block;
  margin-bottom: 0.45rem;
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.section-head h2 {
  margin: 0 0 0.45rem;
  font-size: clamp(1.55rem, 2.5vw, 2.15rem);
  letter-spacing: -0.02em;
}

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

.platform-card,
.feature-card,
.recommend-card,
.scene-card,
.faq-item,
.step-card,
.compat-item,
.download-card,
.docs-panel,
.flow-panel,
.preview-panel {
  background: linear-gradient(180deg, rgba(255,255,255,0.07), rgba(255,255,255,0.025));
  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,
.feature-grid,
.recommend-grid,
.scene-grid,
.compat-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.faq-grid { grid-template-columns: repeat(2, 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: #e2e8f0;
  background: rgba(165, 180, 252, 0.16);
  border: 1px solid rgba(165, 180, 252, 0.28);
}

.status {
  color: #064e3b;
  background: linear-gradient(135deg, #a7f3d0, #6ee7b7);
}

.compat-dot {
  color: #082f49;
  background: linear-gradient(135deg, #bae6fd, #7dd3fc);
  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: linear-gradient(135deg, #f8fafc, #7dd3fc);
}

.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: 11px;
  display: grid;
  place-items: center;
  color: #0b0e14;
  font-weight: 800;
  background: linear-gradient(135deg, #f8fafc, #94a3b8);
}

.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;
  border: 1px solid var(--line);
}

.code-box {
  margin: 0;
  padding: 1rem;
  border-radius: 14px;
  background: #07090d;
  color: #dbeafe;
  font-size: 0.84rem;
  overflow: auto;
  line-height: 1.5;
  border: 1px solid rgba(255,255,255,0.08);
}

.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: rgba(255,255,255,0.04);
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.88rem;
}

.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: rgba(251, 191, 36, 0.08);
  border: 1px solid rgba(251, 191, 36, 0.28);
  color: #fde68a;
}

.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: 2.1rem;
  border-radius: 28px;
  text-align: center;
  color: #0b0e14;
  background:
    radial-gradient(circle at 20% 20%, rgba(255,255,255,0.55), transparent 35%),
    linear-gradient(135deg, #f8fafc 0%, #a8b4c4 35%, #eef2f7 55%, #7c8998 100%);
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.7),
    0 24px 50px rgba(148, 163, 184, 0.2);
}

.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: 0.8;
}

.cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
  justify-content: center;
}

.cta-band .btn-primary {
  background: #0b1220;
  color: #f8fafc;
  box-shadow: none;
}

.cta-band .btn-secondary {
  color: #0b1220;
  border-color: rgba(15, 23, 42, 0.25);
  background: rgba(255,255,255,0.35);
}

.site-footer {
  padding: 2.5rem 0 1.5rem;
  background: #07090d;
  border-top: 1px solid var(--line);
  color: #94a3b8;
}

.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: #f8fafc;
}

.site-footer p {
  margin: 0;
  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, 0.18);
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  font-size: 0.88rem;
}

.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; }
  .hero::before { inset: auto 8% 8% auto; width: 240px; height: 240px; opacity: 0.35; }
}

@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; }
  .metal-stage { min-height: auto; }
}