/* ============================================================
   玄乾科技官网样式 Xuanqian Tech
   深色科技风 · 简约大气 · 无外部依赖（适合境内部署）
   ============================================================ */

:root {
  --bg: #070b14;
  --bg-alt: #0a101e;
  --surface: rgba(255, 255, 255, 0.035);
  --surface-hover: rgba(255, 255, 255, 0.06);
  --border: rgba(255, 255, 255, 0.09);
  --text: #e8ecf4;
  --text-muted: #94a0b8;
  --accent-1: #3b82f6;
  --accent-2: #22d3ee;
  --grad: linear-gradient(120deg, var(--accent-1), var(--accent-2));
  --radius: 16px;
  --nav-h: 72px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI",
          "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei",
          "Noto Sans SC", "Noto Sans CJK SC", "Source Han Sans SC", "WenQuanYi Micro Hei",
          "Helvetica Neue", Arial, sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

::selection { background: rgba(59, 130, 246, 0.35); }

.container {
  width: min(1160px, 92%);
  margin: 0 auto;
}

img, svg { display: block; }

a { color: inherit; text-decoration: none; }

/* ---------- 通用按钮 ---------- */
.btn {
  display: inline-block;
  padding: 0.8em 2em;
  border-radius: 999px;
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: transform 0.25s ease, box-shadow 0.25s ease, background 0.25s ease;
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--grad);
  color: #fff;
  box-shadow: 0 8px 28px rgba(34, 211, 238, 0.22);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 36px rgba(34, 211, 238, 0.34);
}

.btn-ghost {
  border: 1px solid var(--border);
  color: var(--text);
  background: rgba(255, 255, 255, 0.02);
}
.btn-ghost:hover {
  background: var(--surface-hover);
  transform: translateY(-2px);
}

.btn-sm { padding: 0.5em 1.4em; font-size: 0.88rem; }

.grad {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

/* ---------- 导航 ---------- */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  height: var(--nav-h);
  transition: background 0.3s ease, border-color 0.3s ease, backdrop-filter 0.3s ease;
  border-bottom: 1px solid transparent;
}
.nav.scrolled {
  background: rgba(7, 11, 20, 0.78);
  -webkit-backdrop-filter: blur(16px);
  backdrop-filter: blur(16px);
  border-bottom-color: var(--border);
}

.nav-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand { display: flex; align-items: center; }
.brand-name { font-size: 0.98rem; font-weight: 700; letter-spacing: 0.03em; white-space: nowrap; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 30px;
  font-size: 0.93rem;
}
.nav-links > a:not(.nav-cta) {
  color: var(--text-muted);
  transition: color 0.2s ease;
  position: relative;
  padding: 4px 0;
}
.nav-links > a:not(.nav-cta):hover,
.nav-links > a.active { color: var(--text); }
.nav-links > a:not(.nav-cta)::after {
  content: "";
  position: absolute;
  left: 0; bottom: -2px;
  width: 0; height: 2px;
  background: var(--grad);
  border-radius: 2px;
  transition: width 0.25s ease;
}
.nav-links > a:not(.nav-cta):hover::after,
.nav-links > a.active::after { width: 100%; }

.nav-actions { display: flex; align-items: center; gap: 14px; }

.lang-switch {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-muted);
  font-size: 0.85rem;
  font-family: inherit;
  cursor: pointer;
  transition: border-color 0.2s ease;
}
.lang-switch:hover { border-color: rgba(255, 255, 255, 0.25); }
.lang-opt { transition: color 0.2s ease; }
.lang-opt.active { color: var(--text); font-weight: 700; }
.lang-divider { opacity: 0.4; }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px; height: 40px;
  background: none;
  border: 1px solid var(--border);
  border-radius: 10px;
  cursor: pointer;
  padding: 9px;
}
.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.3s ease, opacity 0.3s ease;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- 首屏 ---------- */
.hero {
  position: relative;
  min-height: 100vh; /* 旧内核回退（微信 X5 等不支持 svh） */
  min-height: 100svh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  overflow: hidden;
  padding: calc(var(--nav-h) + 40px) 0 80px;
}

#particles {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(110px);
  opacity: 0.32;
  pointer-events: none;
}
.hero-glow-a {
  width: 480px; height: 480px;
  background: #1d4ed8;
  top: -120px; left: -100px;
}
.hero-glow-b {
  width: 420px; height: 420px;
  background: #0e7490;
  bottom: -140px; right: -80px;
}

.hero-inner { position: relative; z-index: 2; }

.hero-eyebrow {
  display: inline-block;
  font-size: 0.82rem;
  letter-spacing: 0.28em;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 7px 20px;
  margin-bottom: 30px;
  background: rgba(255, 255, 255, 0.02);
}

.hero-title {
  font-size: clamp(2.3rem, 5.6vw, 4.2rem);
  font-weight: 800;
  line-height: 1.22;
  letter-spacing: 0.02em;
  margin-bottom: 24px;
}

.hero-subtitle {
  max-width: 640px;
  margin: 0 auto 40px;
  color: var(--text-muted);
  font-size: clamp(0.98rem, 1.6vw, 1.12rem);
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 52px;
}

.hero-tags {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 10px 14px;
}
.hero-tags span {
  font-size: 0.82rem;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 5px 16px;
  background: rgba(255, 255, 255, 0.02);
}

.hero-scroll {
  position: absolute;
  bottom: 26px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
}
.hero-scroll-line {
  display: block;
  width: 1px;
  height: 44px;
  background: linear-gradient(to bottom, transparent, var(--accent-2));
  animation: scrollPulse 2s ease-in-out infinite;
}
@keyframes scrollPulse {
  0%, 100% { opacity: 0.25; transform: scaleY(0.7); transform-origin: top; }
  50% { opacity: 1; transform: scaleY(1); }
}

/* ---------- 区块通用 ---------- */
.section { padding: 110px 0; }
.section-alt {
  background:
    radial-gradient(900px 420px at 80% 0%, rgba(34, 211, 238, 0.05), transparent 60%),
    var(--bg-alt);
}

.section-head {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 64px;
}
.section-head-left { text-align: left; margin: 0 0 28px; }

.section-tag {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
  margin-bottom: 14px;
}

.section-title {
  font-size: clamp(1.7rem, 3.4vw, 2.5rem);
  font-weight: 800;
  letter-spacing: 0.02em;
  margin-bottom: 16px;
  line-height: 1.3;
}

.section-desc { color: var(--text-muted); font-size: 1rem; }

/* ---------- 卡片网格 ---------- */
.grid { display: grid; gap: 22px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 34px 28px;
  transition: transform 0.3s ease, background 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}
.card:hover {
  transform: translateY(-6px);
  background: var(--surface-hover);
  border-color: rgba(59, 130, 246, 0.45);
  box-shadow: 0 18px 48px rgba(2, 8, 23, 0.55);
}

.card-badge {
  position: absolute;
  top: 20px; right: 20px;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(34, 211, 238, 0.12);
  border: 1px solid rgba(34, 211, 238, 0.35);
  color: var(--accent-2);
}

.card-icon {
  width: 52px; height: 52px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.16), rgba(34, 211, 238, 0.1));
  border: 1px solid rgba(59, 130, 246, 0.28);
}
.card-icon svg {
  width: 26px; height: 26px;
  fill: none;
  stroke: var(--accent-2);
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.card h3 { font-size: 1.12rem; font-weight: 700; margin-bottom: 10px; }
.card p { color: var(--text-muted); font-size: 0.92rem; }

/* ---------- 未来布局 tile ---------- */
.tile {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 30px 26px;
  transition: transform 0.3s ease, border-color 0.3s ease, background 0.3s ease;
}
.tile:hover {
  transform: translateY(-6px);
  border-color: rgba(34, 211, 238, 0.45);
  background: var(--surface-hover);
}
.tile-num {
  display: block;
  font-size: 0.85rem;
  font-weight: 800;
  letter-spacing: 0.18em;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
  margin-bottom: 16px;
}
.tile h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 8px; }
.tile p { color: var(--text-muted); font-size: 0.88rem; }

/* ---------- 关于我们 ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.35fr 1fr;
  gap: 60px;
  align-items: start;
}
.about-text > p {
  color: var(--text-muted);
  margin-bottom: 18px;
  font-size: 0.98rem;
}

.values {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 34px;
}
.value-item {
  border-left: 2px solid;
  border-image: linear-gradient(to bottom, var(--accent-1), var(--accent-2)) 1;
  padding-left: 14px;
}
.value-item h4 { font-size: 0.98rem; margin-bottom: 4px; }
.value-item p { font-size: 0.82rem; color: var(--text-muted); }

.about-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 34px 30px;
  position: sticky;
  top: calc(var(--nav-h) + 24px);
}
.about-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 18px;
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
}
.about-row:last-child { border-bottom: none; }
.about-row dt { color: var(--text-muted); font-size: 0.85rem; flex: none; }
.about-row dd { font-size: 0.9rem; font-weight: 600; text-align: right; }

/* ---------- 合作流程 ---------- */
.steps {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 18px;
  counter-reset: step;
}
.step {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 22px;
  transition: transform 0.3s ease, border-color 0.3s ease;
}
.step:hover { transform: translateY(-5px); border-color: rgba(59, 130, 246, 0.45); }
.step-num {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
  margin-bottom: 14px;
}
.step h3 { font-size: 1rem; font-weight: 700; margin-bottom: 8px; }
.step p { color: var(--text-muted); font-size: 0.84rem; }

/* ---------- 联系我们 ---------- */
.contact-panel {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 56px;
  align-items: center;
  background:
    radial-gradient(620px 300px at 0% 0%, rgba(59, 130, 246, 0.1), transparent 65%),
    var(--surface);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: clamp(34px, 5vw, 64px);
}
.contact-text .section-tag { margin-bottom: 12px; }
.contact-text .section-title { margin-bottom: 14px; }
.contact-text .section-desc { margin-bottom: 30px; }

.contact-list { list-style: none; display: grid; gap: 22px; }
.contact-list li {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border);
}
.contact-list li:last-child { border-bottom: none; padding-bottom: 0; }
.contact-label {
  font-size: 0.78rem;
  letter-spacing: 0.18em;
  color: var(--text-muted);
  text-transform: uppercase;
}
.contact-value { font-size: 0.95rem; font-weight: 600; }
.contact-value a { transition: color 0.2s ease; }
.contact-value a:hover { color: var(--accent-2); }

/* ---------- 页脚 ---------- */
.footer {
  border-top: 1px solid var(--border);
  background: var(--bg-alt);
  padding-top: 64px;
}
.footer-inner {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1.3fr;
  gap: 40px;
  padding-bottom: 48px;
}
.footer-brand p {
  margin-top: 18px;
  color: var(--text-muted);
  font-size: 0.88rem;
  max-width: 260px;
}
.footer-col { display: flex; flex-direction: column; gap: 12px; }
.footer-col h4 {
  font-size: 0.92rem;
  font-weight: 700;
  margin-bottom: 6px;
}
.footer-col a, .footer-col p {
  color: var(--text-muted);
  font-size: 0.86rem;
  transition: color 0.2s ease;
}
.footer-col a:hover { color: var(--text); }

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  padding: 22px 0;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.8rem;
}
.footer-bottom a:hover { color: var(--text); }
.footer-beian { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 16px; }
.gongan-link { display: inline-flex; align-items: center; gap: 5px; }
.gongan-icon { width: 14px; height: auto; display: inline-block; }

/* ---------- 法律页面（隐私政策等） ---------- */
.legal-main {
  padding: calc(var(--nav-h) + 64px) 0 110px;
  background:
    radial-gradient(800px 360px at 85% 0%, rgba(34, 211, 238, 0.05), transparent 60%),
    var(--bg);
}
.legal-main .container { max-width: 820px; }

.legal-title {
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  font-weight: 800;
  letter-spacing: 0.02em;
  margin-bottom: 10px;
}
.legal-meta {
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-bottom: 42px;
  padding-bottom: 26px;
  border-bottom: 1px solid var(--border);
}
.legal-scope {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent-2);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 18px 22px;
  margin-bottom: 36px;
  color: var(--text-muted);
  font-size: 0.93rem;
}
.legal-body h2 {
  font-size: 1.18rem;
  font-weight: 700;
  margin: 40px 0 14px;
  color: var(--text);
}
.legal-body p, .legal-body li {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 12px;
}
.legal-body ul, .legal-body ol { padding-left: 1.4em; margin-bottom: 14px; }
.legal-body li { margin-bottom: 8px; }
.legal-body a { color: var(--accent-2); }
.legal-body a:hover { text-decoration: underline; }
.legal-body strong { color: var(--text); font-weight: 600; }

.legal-home-link {
  color: var(--text-muted);
  font-size: 0.9rem;
  transition: color 0.2s ease;
}
.legal-home-link:hover { color: var(--text); }

.legal-footer {
  border-top: 1px solid var(--border);
  background: var(--bg-alt);
}

/* 双语切换（法律页面用：整块/行内两种粒度） */
.l-en { display: none; }
body.lang-en .l-zh { display: none; }
body.lang-en span.l-en { display: inline; }
body.lang-en article.l-en, body.lang-en div.l-en, body.lang-en p.l-en { display: block; }

/* ---------- 入场动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .hero-scroll-line { animation: none; }
}

/* ---------- 响应式 ---------- */
@media (max-width: 1024px) {
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .about-grid { grid-template-columns: 1fr; gap: 40px; }
  .about-card { position: static; }
  .footer-inner { grid-template-columns: 1fr 1fr; }

  /* 汉堡菜单在 1024px 即启用：桌面导航最小需宽约 880px，
     721–880px 区间（含 iPad 竖屏）会溢出换行 */
  .nav-toggle { display: flex; }
  .nav-links {
    position: fixed;
    top: var(--nav-h);
    left: 0; right: 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
    background: rgba(7, 11, 20, 0.97);
    -webkit-backdrop-filter: blur(18px);
    backdrop-filter: blur(18px);
    border-bottom: 1px solid var(--border);
    padding: 18px 5vw 26px;
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden; /* 收起时移出焦点链与无障碍树 */
    pointer-events: none;
    transition: opacity 0.25s ease, transform 0.25s ease, visibility 0s linear 0.25s;
  }
  .nav-links.open {
    opacity: 1;
    transform: none;
    visibility: visible;
    pointer-events: auto;
    transition: opacity 0.25s ease, transform 0.25s ease;
  }
  .nav-links > a:not(.nav-cta) {
    width: 100%;
    padding: 12px 0;
    font-size: 1rem;
  }
  .nav-links > a:not(.nav-cta)::after { display: none; }
  .nav-cta { margin-top: 12px; }
}

@media (max-width: 720px) {
  .section { padding: 80px 0; }
  .brand-name { font-size: 0.84rem; letter-spacing: 0.01em; }

  .grid-3, .grid-4, .steps { grid-template-columns: 1fr; }
  .values { grid-template-columns: 1fr; gap: 20px; }
  .contact-panel { grid-template-columns: 1fr; gap: 36px; }
  .footer-inner { grid-template-columns: 1fr; gap: 32px; }
  .footer-bottom { justify-content: center; text-align: center; }
  .about-row { flex-direction: column; gap: 2px; }
  .about-row dd { text-align: left; }
}