/* ============================================================
   WisdomStar 星智创享 | 企业官网样式
   结构：变量 → 基础 → 组件 → 区块 → 响应式 → 动效与可访问性
   ============================================================ */

:root {
  --ink: #0b1220;
  --ink-2: #1c2637;
  --body: #4b5565;
  --muted: #7b8595;
  --line: #e5e9ef;
  --bg: #ffffff;
  --bg-soft: #f5f7fa;
  --accent: #ff6a00;
  --accent-dark: #e25c00;
  --accent-soft: #fff1e6;
  --navy: #0c1626;
  --navy-2: #142235;
  --white: #ffffff;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow-sm: 0 2px 10px rgba(12, 22, 38, .05);
  --shadow-md: 0 14px 40px rgba(12, 22, 38, .09);
  --shadow-lg: 0 26px 70px rgba(12, 22, 38, .16);
  --maxw: 1200px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", "Noto Sans", Arial, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 84px; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
h1, h2, h3, p, figure, ul { margin-top: 0; }
ul { padding: 0; list-style: none; }

.container { width: min(100% - 48px, var(--maxw)); margin-inline: auto; }
.svg-sprite { position: absolute; width: 0; height: 0; overflow: hidden; }

.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}

.skip-link {
  position: fixed; top: -100px; left: 16px; z-index: 999;
  padding: 12px 18px; background: var(--accent); color: #fff; border-radius: 0 0 8px 8px;
}
.skip-link:focus { top: 0; }

:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 10px;
  padding: 13px 24px; border: 1px solid transparent; border-radius: 999px;
  font-weight: 600; font-size: 15px; line-height: 1.3; text-align: center;
  transition: transform .2s ease, box-shadow .2s ease, background-color .2s ease, border-color .2s ease;
  white-space: nowrap;
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }
.btn-primary { background: var(--accent); color: #fff; box-shadow: 0 8px 22px rgba(255, 106, 0, .26); }
.btn-primary:hover { background: var(--accent-dark); box-shadow: 0 12px 28px rgba(255, 106, 0, .34); }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn-ghost:hover { border-color: var(--ink); background: var(--bg-soft); }
.btn-sm { padding: 9px 18px; font-size: 14px; }
.btn-lg { padding: 15px 30px; font-size: 16px; }

.text-link { display: inline-flex; align-items: center; gap: 8px; color: var(--accent-dark); font-weight: 650; }
.text-link:hover { gap: 14px; }

/* ---------- 页头 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255, 255, 255, .88);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: box-shadow .25s ease, border-color .25s ease;
}
.site-header.is-scrolled { box-shadow: var(--shadow-sm); border-bottom-color: var(--line); }
.header-inner { display: flex; align-items: center; gap: 28px; min-height: 76px; }

.brand { display: inline-flex; align-items: center; flex-shrink: 0; }
.brand-logo { display: block; width: 168px; height: auto; }
.brand-light .brand-logo { width: 180px; }

.nav { display: flex; align-items: center; gap: 26px; margin-left: auto; }
.nav a { font-size: 14.5px; font-weight: 550; color: var(--ink-2); position: relative; padding: 6px 0; }
.nav a::after {
  content: ""; position: absolute; left: 0; bottom: 0; width: 0; height: 2px;
  background: var(--accent); transition: width .22s ease;
}
.nav a:hover::after, .nav a.is-current::after { width: 100%; }
.nav a:hover { color: var(--accent-dark); }

.header-actions { display: flex; align-items: center; gap: 14px; flex-shrink: 0; }
.lang-switch { display: inline-flex; padding: 3px; background: var(--bg-soft); border: 1px solid var(--line); border-radius: 999px; }
.lang-btn {
  border: 0; background: transparent; color: var(--muted);
  padding: 5px 13px; border-radius: 999px; font-size: 13px; font-weight: 700; line-height: 1.4;
  transition: background-color .2s ease, color .2s ease;
}
.lang-btn.is-active { background: var(--ink); color: #fff; }
.lang-btn:not(.is-active):hover { color: var(--ink); }

.menu-toggle { display: none; width: 42px; height: 42px; border: 1px solid var(--line); border-radius: 10px; background: #fff; padding: 11px 9px; }
.menu-toggle span { display: block; height: 2px; background: var(--ink); border-radius: 2px; margin: 4px 0; transition: transform .25s ease, opacity .2s ease; }
.menu-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.menu-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.menu-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* ---------- 首屏 ---------- */
.hero {
  position: relative; overflow: hidden;
  background:
    radial-gradient(900px 520px at 88% 8%, rgba(255, 106, 0, .10), transparent 65%),
    radial-gradient(700px 460px at 4% 90%, rgba(24, 56, 96, .07), transparent 70%),
    linear-gradient(180deg, #fff 0%, #fafbfd 100%);
}
.hero::before {
  content: ""; position: absolute; inset: 0; pointer-events: none; opacity: .45;
  background-image: linear-gradient(rgba(12, 22, 38, .045) 1px, transparent 1px), linear-gradient(90deg, rgba(12, 22, 38, .045) 1px, transparent 1px);
  background-size: 56px 56px; mask-image: linear-gradient(to bottom, #000, transparent 85%);
}
.hero-grid { position: relative; display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.02fr); gap: 48px; align-items: center; padding-block: 84px 72px; }
.hero-copy { max-width: 580px; }

.eyebrow { display: inline-flex; align-items: center; gap: 9px; font-size: 12.5px; font-weight: 750; letter-spacing: .13em; text-transform: uppercase; color: var(--accent-dark); margin-bottom: 22px; }
.eyebrow-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 0 5px rgba(255, 106, 0, .16); }

.hero-title { font-size: clamp(34px, 4.4vw, 60px); line-height: 1.22; letter-spacing: -.02em; font-weight: 800; margin-bottom: 24px; }
.hero-title span { display: block; }
.hero-title .accent { color: var(--accent); }
.hero-sub { color: var(--body); font-size: 16.5px; line-height: 1.9; margin-bottom: 32px; }
.hero-buttons { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 30px; }
.hero-tagline { font-size: 13px; color: var(--muted); letter-spacing: .04em; margin-bottom: 0; }

.hero-visual { position: relative; }
.hero-image-wrap { position: relative; border-radius: 24px; background: #fff; padding: 16px; box-shadow: var(--shadow-lg); }
.hero-image-wrap picture, .hero-image-wrap img { width: 100%; height: auto; border-radius: 14px; }
.hero-badge {
  position: absolute; display: flex; align-items: center; gap: 9px;
  background: rgba(255, 255, 255, .95); backdrop-filter: blur(8px);
  border: 1px solid var(--line); border-radius: 999px; padding: 9px 16px;
  box-shadow: var(--shadow-md); font-size: 12.5px; font-weight: 650; white-space: nowrap;
}
.hero-badge-top { top: 24px; left: -22px; }
.hero-badge-bottom { bottom: 24px; right: -18px; flex-direction: column; align-items: flex-start; gap: 1px; border-radius: 14px; }
.hero-badge-bottom strong { font-size: 19px; color: var(--accent); line-height: 1.2; }
.hero-badge-bottom span { font-size: 11.5px; color: var(--muted); font-weight: 550; }
.badge-dot { width: 7px; height: 7px; border-radius: 50%; background: #22b573; flex-shrink: 0; }
.scroll-hint { display: inline-flex; align-items: center; gap: 9px; margin-top: 22px; font-size: 12px; letter-spacing: .1em; color: var(--muted); }
.scroll-hint:hover { color: var(--accent-dark); }

/* ---------- 数据条 ---------- */
.stats { background: var(--navy); color: #fff; }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); }
.stat { padding: 34px 18px; text-align: center; border-right: 1px solid rgba(255, 255, 255, .1); }
.stat:last-child { border-right: 0; }
.stat strong { display: block; font-size: clamp(30px, 3.2vw, 44px); font-weight: 800; line-height: 1.15; letter-spacing: -.02em; color: #fff; }
.stat strong span { font-size: .42em; font-weight: 650; margin-left: 5px; color: var(--accent); }
.stat > span { display: block; font-size: 13px; color: rgba(255, 255, 255, .65); margin-top: 8px; }

/* ---------- 通用区块 ---------- */
.section { padding-block: 96px; }
.section-soft { background: var(--bg-soft); }
.section-dark { background: var(--navy); color: #fff; }
.section-head { max-width: 720px; margin: 0 auto 52px; text-align: center; }
.section-head h2 { font-size: clamp(28px, 3.2vw, 40px); line-height: 1.3; letter-spacing: -.015em; font-weight: 800; margin-bottom: 16px; }
.section-lead { color: var(--body); font-size: 16px; line-height: 1.85; margin-bottom: 0; }
.section-head-light h2 { color: #fff; }
.section-head-light .section-lead { color: rgba(255, 255, 255, .7); }
.section-head-light .eyebrow { color: #ff9448; }

/* ---------- 关于我们 ---------- */
.about-grid { display: grid; grid-template-columns: minmax(0, .85fr) minmax(0, 1.15fr); gap: 56px; align-items: start; }
.about-text p { color: var(--body); line-height: 1.95; margin-bottom: 20px; }
.about-text .text-link { margin-top: 8px; }
.value-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.value-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 26px 22px; box-shadow: var(--shadow-sm); transition: transform .25s ease, box-shadow .25s ease; }
.value-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); }
.value-icon, .feature-icon, .system-icon, .app-icon {
  display: inline-flex; align-items: center; justify-content: center;
  width: 46px; height: 46px; border-radius: 12px; background: var(--accent-soft); color: var(--accent-dark); margin-bottom: 18px;
}
.value-icon svg, .feature-icon svg, .system-icon svg, .app-icon svg {
  width: 24px; height: 24px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round;
}
.value-card h3 { font-size: 18px; font-weight: 750; margin-bottom: 10px; }
.value-card p { font-size: 13.5px; line-height: 1.8; color: var(--body); margin-bottom: 0; }

/* ---------- 产品图集 ---------- */
.gallery { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.gallery-item { margin: 0; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow-sm); cursor: zoom-in; transition: transform .25s ease, box-shadow .25s ease; }
.gallery-item:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); }
.gallery-item picture { display: block; aspect-ratio: 4 / 3; background: #fff; overflow: hidden; }
.gallery-item img { width: 100%; height: 100%; object-fit: contain; }
.gallery-item figcaption { display: flex; justify-content: space-between; align-items: center; gap: 10px; padding: 15px 18px; border-top: 1px solid var(--line); font-size: 14px; font-weight: 650; }
.gallery-index { font-size: 11.5px; color: var(--muted); letter-spacing: .08em; }
.gallery-hint { text-align: center; color: var(--muted); font-size: 13px; margin: 22px 0 0; }

/* ---------- 技术优势 ---------- */
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.feature-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 30px 26px; transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease; }
.feature-card:hover { transform: translateY(-6px); border-color: rgba(255, 106, 0, .35); box-shadow: var(--shadow-md); }
.feature-card h3 { font-size: 18px; font-weight: 750; margin-bottom: 12px; }
.feature-card p { color: var(--body); font-size: 14px; line-height: 1.85; margin-bottom: 0; }

/* ---------- 技术参数 ---------- */
.spec-tabs { display: flex; flex-wrap: wrap; justify-content: center; gap: 8px; margin-bottom: 28px; }
.spec-tab { border: 1px solid var(--line); background: #fff; color: var(--body); padding: 9px 20px; border-radius: 999px; font-size: 14px; font-weight: 650; transition: background-color .2s ease, color .2s ease, border-color .2s ease; }
.spec-tab:hover { border-color: var(--accent); color: var(--accent-dark); }
.spec-tab.is-active { background: var(--ink); border-color: var(--ink); color: #fff; }
.spec-panels { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow-sm); padding: 10px 30px 24px; }
.spec-panel[hidden] { display: none; }
.spec-table { width: 100%; border-collapse: collapse; font-size: 14.5px; }
.spec-table thead th { text-align: left; font-size: 12.5px; letter-spacing: .06em; color: var(--muted); font-weight: 700; padding: 16px 10px; border-bottom: 2px solid var(--line); }
.spec-table thead th:first-child { width: 38%; }
.spec-table tbody tr { border-bottom: 1px solid var(--line); }
.spec-table tbody tr:last-child { border-bottom: 0; }
.spec-table tbody td { padding: 14px 10px; vertical-align: top; }
.spec-table tbody td:first-child { color: var(--body); }
.spec-table tbody td:last-child { font-weight: 650; color: var(--ink); }
.spec-note { text-align: center; color: var(--muted); font-size: 12.5px; margin: 20px 0 0; }

/* ---------- 系统组成 ---------- */
.system-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.system-card { background: var(--bg-soft); border: 1px solid var(--line); border-radius: var(--radius); padding: 28px 24px; transition: transform .25s ease, background-color .25s ease; }
.system-card:hover { transform: translateY(-5px); background: #fff; box-shadow: var(--shadow-md); }
.system-card h3 { font-size: 17px; font-weight: 750; margin-bottom: 10px; letter-spacing: .01em; }
.system-card p { color: var(--body); font-size: 13.5px; line-height: 1.8; margin-bottom: 16px; }
.chip { display: inline-block; background: var(--accent-soft); color: var(--accent-dark); font-size: 11.5px; font-weight: 700; letter-spacing: .03em; padding: 5px 12px; border-radius: 999px; }

/* ---------- 应用场景 ---------- */
.app-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.app-card { background: rgba(255, 255, 255, .045); border: 1px solid rgba(255, 255, 255, .12); border-radius: var(--radius); padding: 28px 24px; transition: transform .25s ease, background-color .25s ease, border-color .25s ease; }
.app-card:hover { transform: translateY(-5px); background: rgba(255, 255, 255, .08); border-color: rgba(255, 148, 72, .55); }
.app-icon { background: rgba(255, 106, 0, .16); color: #ff9448; }
.app-card h3 { font-size: 17px; font-weight: 700; margin-bottom: 10px; color: #fff; }
.app-card p { font-size: 13.5px; line-height: 1.8; color: rgba(255, 255, 255, .66); margin-bottom: 0; }

/* ---------- 解决方案流程 ---------- */
.flow-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; position: relative; }
.flow-step { position: relative; border-top: 3px solid var(--accent); padding: 26px 22px 22px; background: var(--bg-soft); border-radius: 0 0 var(--radius) var(--radius); }
.flow-num { display: block; font-size: 30px; font-weight: 800; color: var(--accent); line-height: 1; margin-bottom: 14px; letter-spacing: -.03em; }
.flow-step h3 { font-size: 16px; font-weight: 750; margin-bottom: 10px; }
.flow-step p { font-size: 13.5px; line-height: 1.8; color: var(--body); margin-bottom: 0; }
.sol-note { display: flex; align-items: center; gap: 14px; margin-top: 28px; padding: 18px 24px; border-radius: var(--radius); background: var(--accent-soft); color: var(--accent-dark); }
.sol-note svg { width: 22px; height: 22px; flex-shrink: 0; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.sol-note p { margin: 0; font-size: 14.5px; font-weight: 600; }

/* ---------- 行动号召 ---------- */
.cta-band { background: linear-gradient(115deg, var(--navy) 0%, var(--navy-2) 55%, #23364f 100%); color: #fff; padding-block: 58px; }
.cta-inner { display: flex; align-items: center; justify-content: space-between; gap: 30px; flex-wrap: wrap; }
.cta-inner h2 { font-size: clamp(24px, 2.6vw, 32px); font-weight: 800; margin-bottom: 8px; }
.cta-inner p { color: rgba(255, 255, 255, .7); margin-bottom: 0; font-size: 15px; }

/* ---------- 联系我们 ---------- */
.contact-grid { display: grid; grid-template-columns: minmax(0, .85fr) minmax(0, 1.15fr); gap: 48px; align-items: start; }
.contact-info h3 { font-size: 19px; font-weight: 750; margin-bottom: 22px; }
.contact-list li { display: flex; align-items: flex-start; gap: 13px; margin-bottom: 16px; font-size: 14.5px; color: var(--body); }
.contact-list svg { width: 19px; height: 19px; flex-shrink: 0; margin-top: 3px; color: var(--accent); fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.contact-list a:hover { color: var(--accent-dark); text-decoration: underline; }
.contact-hours { font-size: 13px; color: var(--muted); margin: 24px 0 0; padding-top: 20px; border-top: 1px solid var(--line); }

.contact-form { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 30px; box-shadow: var(--shadow-sm); }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.form-field { margin-bottom: 18px; }
.form-field label { display: block; font-size: 13.5px; font-weight: 650; margin-bottom: 8px; color: var(--ink-2); }
.form-field input, .form-field select, .form-field textarea {
  width: 100%; border: 1px solid var(--line); border-radius: var(--radius-sm); background: #fbfcfe;
  padding: 12px 14px; color: var(--ink); font-size: 14.5px; transition: border-color .2s ease, box-shadow .2s ease;
}
.form-field textarea { resize: vertical; min-height: 110px; }
.form-field input:focus, .form-field select:focus, .form-field textarea:focus {
  outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px rgba(255, 106, 0, .13); background: #fff;
}
.form-field :is(input, textarea).invalid { border-color: #d64545; }
.form-note { font-size: 12.5px; color: var(--muted); margin: 14px 0 0; }
.form-status { font-size: 13.5px; font-weight: 600; margin: 10px 0 0; min-height: 1em; }
.form-status.is-ok { color: #16855a; }
.form-status.is-err { color: #d64545; }

/* ---------- 页脚 ---------- */
.site-footer { background: #08111f; color: rgba(255, 255, 255, .72); padding-top: 64px; }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr; gap: 48px; padding-bottom: 48px; }
.footer-brand p { font-size: 13.5px; line-height: 1.85; max-width: 330px; margin: 20px 0 0; }
.footer-slogan { color: #ff9448 !important; font-weight: 650; letter-spacing: .04em; margin-top: 8px !important; }
.footer-col h3 { color: #fff; font-size: 15px; font-weight: 700; margin-bottom: 18px; }
.footer-col li { font-size: 13.5px; margin-bottom: 11px; }
.footer-col a:hover { color: #ff9448; }
.footer-lang { display: inline-flex; gap: 6px; margin-top: 16px; }
.footer-lang .lang-btn { border: 1px solid rgba(255, 255, 255, .2); background: transparent; color: rgba(255, 255, 255, .65); padding: 6px 14px; }
.footer-lang .lang-btn.is-active { background: var(--accent); border-color: var(--accent); color: #fff; }
.footer-bottom { display: flex; justify-content: space-between; gap: 14px; flex-wrap: wrap; border-top: 1px solid rgba(255, 255, 255, .1); padding-block: 22px; font-size: 12.5px; color: rgba(255, 255, 255, .45); }
.footer-bottom p { margin: 0; }

/* ---------- 回到顶部 / 大图 ---------- */
.back-top {
  position: fixed; right: 22px; bottom: 22px; z-index: 90;
  width: 44px; height: 44px; border: 0; border-radius: 50%; background: var(--ink); color: #fff;
  font-size: 19px; line-height: 1; box-shadow: var(--shadow-md);
  opacity: 0; visibility: hidden; transform: translateY(12px);
  transition: opacity .25s ease, transform .25s ease, visibility .25s ease, background-color .2s ease;
}
.back-top.is-visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-top:hover { background: var(--accent); }

.lightbox { border: 0; padding: 18px; background: #fff; border-radius: 18px; box-shadow: 0 30px 90px rgba(0, 0, 0, .35); max-width: min(94vw, 1200px); max-height: 92dvh; }
.lightbox::backdrop { background: rgba(5, 12, 22, .82); backdrop-filter: blur(4px); }
.lightbox img { max-width: 100%; max-height: 72dvh; object-fit: contain; border-radius: 10px; }
.lightbox p { text-align: center; color: var(--body); font-size: 14px; margin: 12px 0 2px; }
.lightbox-close { position: absolute; top: 10px; right: 12px; width: 36px; height: 36px; border: 0; border-radius: 50%; background: var(--bg-soft); color: var(--ink); font-size: 24px; line-height: 1; }
.lightbox-close:hover { background: var(--accent); color: #fff; }

/* ---------- 滚动显现 ---------- */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity .6s ease, transform .6s ease; }
.reveal.is-visible { opacity: 1; transform: none; }

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1080px) {
  .nav { gap: 18px; }
  .nav a { font-size: 13.5px; }
  .header-cta { display: none; }
  .hero-badge-top { left: -8px; }
  .hero-badge-bottom { right: -6px; }
  .value-cards, .feature-grid, .system-grid, .app-grid { grid-template-columns: repeat(2, 1fr); }
  .flow-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 900px) {
  .header-inner { min-height: 68px; }
  .menu-toggle { display: block; }
  .nav {
    position: fixed; inset: 68px 0 auto 0; z-index: 99;
    display: none; flex-direction: column; align-items: stretch; gap: 0;
    background: #fff; padding: 12px 24px 24px; border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow-md); max-height: calc(100dvh - 68px); overflow-y: auto;
  }
  .nav.is-open { display: flex; }
  .nav a { font-size: 16px; padding: 13px 4px; border-bottom: 1px solid var(--line); }
  .nav a::after { display: none; }
  .hero-grid { grid-template-columns: 1fr; gap: 40px; padding-block: 60px 56px; }
  .hero-copy { max-width: none; }
  .hero-visual { max-width: 620px; margin-inline: auto; width: 100%; }
  .about-grid, .contact-grid { grid-template-columns: 1fr; gap: 36px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 36px; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 720px) {
  .brand-logo { width: 132px; }
  .brand-light .brand-logo { width: 140px; }
  .container { width: min(100% - 32px, var(--maxw)); }
  html { scroll-padding-top: 68px; }
  .section { padding-block: 68px; }
  .section-head { margin-bottom: 36px; }
  .hero-title { font-size: clamp(30px, 8vw, 42px); }
  .hero-sub { font-size: 15px; }
  .hero-buttons .btn { flex: 1 1 auto; }
  .hero-badge { font-size: 11px; padding: 7px 12px; }
  .hero-badge-bottom strong { font-size: 16px; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .stat { padding: 24px 10px; border-bottom: 1px solid rgba(255, 255, 255, .1); }
  .stat:nth-child(2) { border-right: 0; }
  .stat:nth-child(3), .stat:nth-child(4) { border-bottom: 0; }
  .value-cards, .feature-grid, .system-grid, .app-grid, .flow-grid, .gallery { grid-template-columns: 1fr; }
  .gallery-item picture { aspect-ratio: 16 / 10; }
  .spec-panels { padding: 8px 16px 18px; }
  .spec-table, .spec-table tbody, .spec-table tbody tr, .spec-table tbody td { display: block; width: 100%; }
  .spec-table thead { display: none; }
  .spec-table tbody tr { display: grid; grid-template-columns: minmax(110px, 44%) 1fr; gap: 8px; padding: 12px 0; border-bottom: 1px solid var(--line); }
  .spec-table tbody td { padding: 0; font-size: 13.5px; }
  .spec-table tbody td:first-child { color: var(--muted); }
  .spec-tabs { justify-content: flex-start; flex-wrap: nowrap; overflow-x: auto; padding-bottom: 6px; scrollbar-width: thin; }
  .spec-tab { flex: 0 0 auto; }
  .cta-inner { flex-direction: column; align-items: flex-start; }
  .form-row { grid-template-columns: 1fr; gap: 0; }
  .contact-form { padding: 22px; }
  .footer-grid { grid-template-columns: 1fr; gap: 30px; }
  .footer-brand { grid-column: auto; }
  .footer-bottom { flex-direction: column; }
  .back-top { right: 14px; bottom: 14px; }
}

@media (max-width: 400px) {
  .brand-logo { width: 116px; }
  .brand-light .brand-logo { width: 126px; }
  .lang-btn { padding: 5px 10px; }
  .hero-badge-top { left: 0; top: 12px; }
  .hero-badge-bottom { right: 0; bottom: 12px; }
}

/* ============================================================
   动效偏好与打印
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
  .reveal { opacity: 1; transform: none; }
}

@media print {
  .site-header, .back-top, .cta-band, .lightbox, .hero-buttons, .scroll-hint { display: none !important; }
  .section-dark { background: #fff; color: #000; }
  .app-card { border-color: #ccc; }
  .app-card h3, .app-card p { color: #000; }
}