/* =========================================================
   荷气AI 官网样式
   配色：深色科技底 #060B18 / 主蓝 #2B6CB0 / 青 #22D3EE / 青绿 #00A896
   断点：≥1200 桌面 / 768–1199 平板 / <768 移动
   ========================================================= */

:root {
  --bg: #060B18;
  --bg-soft: #0A1424;
  --bg-elev: #0E1B30;

  --primary: #2B6CB0;
  --primary-light: #4C8FD6;
  --cyan: #22D3EE;
  --teal: #00A896;

  --text: #E8EEF8;
  --text-mid: #A9B7CE;
  --text-dim: #7488A5;

  --line: rgba(255, 255, 255, 0.09);
  --line-strong: rgba(255, 255, 255, 0.16);

  --glass: rgba(255, 255, 255, 0.045);
  --glass-strong: rgba(255, 255, 255, 0.07);

  --grad: linear-gradient(120deg, #4C8FD6 0%, #22D3EE 55%, #00A896 100%);
  --grad-soft: linear-gradient(135deg, rgba(43, 108, 176, 0.22), rgba(34, 211, 238, 0.12));

  --radius: 18px;
  --radius-sm: 12px;
  --shadow: 0 24px 60px -28px rgba(0, 0, 0, 0.85);
  --shadow-glow: 0 18px 50px -20px rgba(34, 211, 238, 0.35);

  --container: 1200px;
  --header-h: 72px;

  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC",
    system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-h) + 16px); }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

body.nav-open { overflow: hidden; }

img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }
h1, h2, h3, h4 { margin: 0 0 .5em; line-height: 1.25; font-weight: 700; letter-spacing: -0.01em; }
p { margin: 0 0 1em; }
ul { margin: 0; padding: 0; list-style: none; }
button { font-family: inherit; }

.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 24px; }

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

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 200;
  background: var(--primary); color: #fff; padding: 10px 16px; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* ---------------- 按钮 ---------------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 14px 26px; border-radius: 999px; border: 1px solid transparent;
  font-size: 15px; font-weight: 600; cursor: pointer; white-space: nowrap;
  transition: transform .22s ease, box-shadow .22s ease, background .22s ease, border-color .22s ease;
}
.btn-sm { padding: 9px 18px; font-size: 14px; }
.btn-block { width: 100%; }

.btn-primary {
  background: var(--grad);
  color: #04121F;
  box-shadow: var(--shadow-glow);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 22px 56px -18px rgba(34, 211, 238, 0.5); }

.btn-ghost {
  background: rgba(255, 255, 255, 0.05);
  border-color: var(--line-strong);
  color: var(--text);
}
.btn-ghost:hover { background: rgba(255, 255, 255, 0.1); transform: translateY(-2px); }

/* ---------------- 头部导航 ---------------- */
.site-header {
  position: fixed; inset: 0 0 auto 0; z-index: 100;
  height: var(--header-h);
  display: flex; align-items: center;
  background: rgba(6, 11, 24, 0.6);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid transparent;
  transition: background .3s ease, border-color .3s ease;
}
.site-header.is-scrolled {
  background: #070D1B;
  border-bottom-color: var(--line);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; gap: 20px; }

.brand { display: inline-flex; align-items: center; gap: 10px; flex: none; }
.brand-mark { display: inline-flex; }
.brand-text { font-size: 20px; font-weight: 800; letter-spacing: -0.02em; }

.nav { display: flex; align-items: center; gap: 6px; }
.nav > a {
  position: relative;
  padding: 8px 14px; border-radius: 10px;
  font-size: 15px; color: var(--text-mid);
  transition: color .2s ease, background .2s ease;
}
.nav > a:hover { color: var(--text); background: rgba(255, 255, 255, 0.05); }
.nav > a.nav-cta { margin-left: 10px; color: #04121F; }
.nav > a.nav-cta:hover { color: #04121F; background: none; }

.nav-toggle {
  display: none; width: 42px; height: 42px; border-radius: 12px;
  background: rgba(255, 255, 255, 0.05); border: 1px solid var(--line);
  cursor: pointer; padding: 0; position: relative;
}
.nav-toggle span {
  position: absolute; left: 50%; width: 18px; height: 2px; border-radius: 2px;
  background: var(--text); transform: translateX(-50%);
  transition: transform .3s ease, opacity .3s ease, top .3s ease;
}
.nav-toggle span:nth-child(1) { top: 15px; }
.nav-toggle span:nth-child(2) { top: 20px; }
.nav-toggle span:nth-child(3) { top: 25px; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { top: 20px; transform: translateX(-50%) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { top: 20px; transform: translateX(-50%) rotate(-45deg); }

/* ---------------- 通用区块 ---------------- */
.section { position: relative; padding: 104px 0; }
.section-alt { background: linear-gradient(180deg, rgba(10, 20, 36, 0.85), rgba(6, 11, 24, 0.2)); }
.section-alt::before {
  content: ""; position: absolute; inset: 0 0 auto 0; height: 1px;
  background: linear-gradient(90deg, transparent, var(--line-strong), transparent);
}

.section-head { max-width: 760px; margin: 0 auto 56px; text-align: center; }
.section-head h2 { font-size: clamp(26px, 3.4vw, 40px); }
.section-desc { color: var(--text-mid); font-size: 16.5px; margin: 0; }

.eyebrow {
  display: inline-flex; align-items: center; gap: 9px;
  margin: 0 0 16px; padding: 7px 16px;
  border: 1px solid var(--line-strong); border-radius: 999px;
  background: rgba(255, 255, 255, 0.04);
  font-size: 13.5px; font-weight: 600; letter-spacing: .04em; color: var(--text-mid);
}
.eyebrow .dot {
  width: 7px; height: 7px; border-radius: 50%; background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(34, 211, 238, 0.16);
}

/* 玻璃卡片 */
.glass {
  background: var(--glass);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.card {
  background: linear-gradient(160deg, rgba(255, 255, 255, 0.06), rgba(255, 255, 255, 0.02));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px;
  transition: transform .3s ease, border-color .3s ease, box-shadow .3s ease;
}
.card:hover { transform: translateY(-4px); border-color: rgba(34, 211, 238, 0.35); box-shadow: var(--shadow); }

/* ---------------- Hero ---------------- */
.hero { position: relative; padding: calc(var(--header-h) + 72px) 0 72px; overflow: hidden; }
.hero-bg { position: absolute; inset: 0; pointer-events: none; overflow: hidden; }
.hero-bg::after {
  content: ""; position: absolute; inset: 0;
  background:
    radial-gradient(120% 80% at 50% -10%, rgba(43, 108, 176, 0.28), transparent 60%),
    linear-gradient(180deg, transparent 45%, var(--bg) 100%);
}
.grid-mask {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.045) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(90% 70% at 50% 20%, #000 20%, transparent 75%);
  -webkit-mask-image: radial-gradient(90% 70% at 50% 20%, #000 20%, transparent 75%);
}
.orb { position: absolute; border-radius: 50%; filter: blur(70px); opacity: .5; }
.orb-1 { width: 460px; height: 460px; top: -120px; left: -80px; background: rgba(43, 108, 176, 0.75); }
.orb-2 { width: 380px; height: 380px; top: 60px; right: -60px; background: rgba(34, 211, 238, 0.4); }
.orb-3 { width: 300px; height: 300px; bottom: -140px; left: 40%; background: rgba(0, 168, 150, 0.32); }

.hero-inner {
  position: relative; z-index: 2;
  display: grid; grid-template-columns: 1.05fr 1fr; gap: 56px; align-items: center;
}

.hero-copy h1 { font-size: clamp(32px, 4.6vw, 56px); margin-bottom: 20px; }
.hero-sub { color: var(--text-mid); font-size: 17px; max-width: 560px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin: 28px 0 26px; }

.hero-trust { display: flex; flex-wrap: wrap; gap: 10px 22px; }
.hero-trust li {
  position: relative; padding-left: 18px;
  font-size: 14px; color: var(--text-dim);
}
.hero-trust li::before {
  content: ""; position: absolute; left: 0; top: 50%; transform: translateY(-50%);
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--grad); box-shadow: 0 0 10px rgba(34, 211, 238, 0.6);
}

.hero-visual { position: relative; }
.hero-card { padding: 12px; box-shadow: var(--shadow), var(--shadow-glow); }

/* 媒体容器：内联 SVG 打底，远程图片加载成功后覆盖其上 */
.svg-sprite { position: absolute; width: 0; height: 0; overflow: hidden; }

.media {
  position: relative; overflow: hidden; border-radius: 12px;
  aspect-ratio: 16 / 9; background: #08111F;
}
.media .art, .scene-media .art {
  position: absolute; inset: 0; z-index: 0;
  width: 100%; height: 100%; display: block;
}
.media img {
  position: relative; z-index: 1;
  width: 100%; height: 100%; object-fit: cover; display: block;
  opacity: 0; transition: opacity .45s ease;
}
.media img.is-loaded { opacity: 1; }
.media img.is-broken, .scene-media img.is-broken { display: none; }

.float-chip {
  position: absolute; display: inline-flex; align-items: center; gap: 8px;
  padding: 10px 16px; border-radius: 999px;
  background: rgba(10, 20, 36, 0.88);
  border: 1px solid var(--line-strong);
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  font-size: 13.5px; color: var(--text-mid); white-space: nowrap;
  box-shadow: var(--shadow);
  animation: floaty 6s ease-in-out infinite;
}
.chip-a { top: 14px; left: -26px; }
.chip-b { bottom: 18px; right: -18px; animation-delay: -3s; }
.chip-dot { width: 8px; height: 8px; border-radius: 50%; }
.c-cyan { background: var(--cyan); box-shadow: 0 0 10px var(--cyan); }
.c-teal { background: var(--teal); box-shadow: 0 0 10px var(--teal); }

@keyframes floaty {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

/* 数据条 */
.stats {
  position: relative; z-index: 2;
  margin-top: 72px; padding: 30px 20px;
  display: grid; grid-template-columns: repeat(4, 1fr);
}
.stat { text-align: center; padding: 6px 16px; border-right: 1px solid var(--line); }
.stat:last-child { border-right: none; }
.stat-num {
  display: block; font-size: clamp(26px, 3vw, 38px); font-weight: 800; letter-spacing: -0.02em;
  background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent;
}
.stat-label { display: block; margin-top: 6px; font-size: 13.5px; color: var(--text-dim); }

/* ---------------- 产品功能 ---------------- */
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }

.card-icon {
  display: inline-flex; align-items: center; justify-content: center;
  width: 46px; height: 46px; margin-bottom: 18px; border-radius: 13px;
  background: var(--grad-soft); border: 1px solid var(--line-strong);
  color: var(--cyan);
}
.feature-card h3 { font-size: 19px; margin-bottom: 10px; }
.feature-card p { color: var(--text-mid); font-size: 14.8px; margin-bottom: 16px; }

.tag-list { display: flex; flex-wrap: wrap; gap: 8px; }
.tag-list li {
  padding: 5px 12px; border-radius: 999px;
  background: rgba(255, 255, 255, 0.05); border: 1px solid var(--line);
  font-size: 12.5px; color: var(--text-mid);
}

/* ---------------- 技术优势 ---------------- */
.tech-layout { display: grid; grid-template-columns: 1.5fr 1fr; gap: 32px; align-items: start; }

.tech-list { display: grid; gap: 6px; }
.tech-list li {
  display: flex; gap: 20px;
  padding: 22px 20px; border-radius: var(--radius-sm);
  border: 1px solid transparent;
  transition: background .25s ease, border-color .25s ease;
}
.tech-list li:hover { background: rgba(255, 255, 255, 0.04); border-color: var(--line); }
.tech-idx {
  flex: none; font-size: 14px; font-weight: 800; letter-spacing: .06em;
  background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent;
  padding-top: 3px;
}
.tech-list h3 { font-size: 17.5px; margin-bottom: 6px; }
.tech-list p { color: var(--text-mid); font-size: 14.8px; margin: 0; }

.tech-panel { padding: 28px; position: sticky; top: calc(var(--header-h) + 24px); }
.panel-title { font-size: 16px; font-weight: 700; margin: 0 0 6px; }
.panel-sub { font-size: 14px; color: var(--text-dim); margin-bottom: 18px; }
.spec-list { margin: 0 0 16px; }
.spec-list > div {
  display: flex; justify-content: space-between; gap: 16px;
  padding: 11px 0; border-bottom: 1px dashed var(--line);
}
.spec-list > div:last-child { border-bottom: none; }
.spec-list dt { color: var(--text-dim); font-size: 14px; }
.spec-list dd { margin: 0; font-size: 14.5px; font-weight: 600; color: var(--text); text-align: right; }
.panel-note { font-size: 13px; color: var(--text-dim); margin: 0; }

/* ---------------- 应用场景 ---------------- */
.scene-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.scene-card {
  overflow: hidden; border-radius: var(--radius);
  border: 1px solid var(--line);
  background: linear-gradient(160deg, rgba(255, 255, 255, 0.055), rgba(255, 255, 255, 0.015));
  transition: transform .3s ease, border-color .3s ease, box-shadow .3s ease;
}
.scene-card:hover { transform: translateY(-4px); border-color: rgba(34, 211, 238, 0.32); box-shadow: var(--shadow); }
.scene-media { position: relative; aspect-ratio: 16 / 10; overflow: hidden; background: #08111F; }
.scene-media::after {
  content: ""; position: absolute; inset: 0; z-index: 2;
  background: linear-gradient(180deg, rgba(6, 11, 24, 0.05), rgba(6, 11, 24, 0.85));
}
.scene-media img {
  position: relative; z-index: 1;
  width: 100%; height: 100%; object-fit: cover;
  opacity: 0; transition: opacity .45s ease, transform .5s ease;
}
.scene-media img.is-loaded { opacity: 1; }
.scene-card:hover .scene-media img { transform: scale(1.05); }
.scene-body { padding: 24px 26px 28px; }
.scene-tag {
  display: inline-block; margin-bottom: 10px; padding: 4px 12px; border-radius: 999px;
  background: var(--grad-soft); border: 1px solid var(--line-strong);
  font-size: 12.5px; color: var(--cyan); font-weight: 600;
}
.scene-body h3 { font-size: 20px; }
.scene-body p { color: var(--text-mid); font-size: 14.8px; }
.scene-path {
  margin: 0; padding-top: 14px; border-top: 1px dashed var(--line);
  font-size: 13.5px !important; color: var(--text-dim) !important;
}
.scene-path b { color: var(--text); margin-right: 8px; }

/* ---------------- 案例 ---------------- */
.case-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.case-meta {
  display: inline-block; margin-bottom: 12px; font-size: 12.5px; letter-spacing: .05em;
  color: var(--teal); font-weight: 600;
}
.case-card h3 { font-size: 18.5px; }
.case-card > p { color: var(--text-mid); font-size: 14.8px; }
.case-points { display: grid; gap: 8px; padding-top: 14px; border-top: 1px dashed var(--line); }
.case-points li { font-size: 13.5px; color: var(--text-dim); }
.case-points b { color: var(--text-mid); margin-right: 8px; font-weight: 600; }
.case-note { margin: 34px 0 0; text-align: center; font-size: 14px; color: var(--text-dim); }

/* ---------------- 关于我们 ---------------- */
.about-layout { display: grid; grid-template-columns: 1.35fr 1fr; gap: 40px; align-items: start; }
.about-copy h2 { font-size: clamp(24px, 3vw, 36px); }
.about-copy > p { color: var(--text-mid); }
.about-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; margin-top: 26px; }
.about-item {
  padding: 16px 18px; border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.04); border: 1px solid var(--line);
}
.about-item b { display: block; font-size: 14.5px; margin-bottom: 4px; }
.about-item span { font-size: 13.3px; color: var(--text-dim); line-height: 1.6; }

.about-panel { padding: 26px; }
.boundary-list { display: grid; gap: 10px; margin-bottom: 16px; }
.boundary-list li {
  display: flex; align-items: flex-start; gap: 10px;
  font-size: 14px; color: var(--text-mid);
}
.boundary-list li span {
  flex: none; min-width: 56px; text-align: center;
  padding: 2px 8px; border-radius: 6px; font-size: 12px; font-weight: 600;
}
.boundary-list li.ok span { background: rgba(0, 168, 150, 0.16); color: #37D6C0; border: 1px solid rgba(0, 168, 150, 0.35); }
.boundary-list li.no span { background: rgba(255, 255, 255, 0.06); color: var(--text-dim); border: 1px solid var(--line); }

/* ---------------- 常见问题 ---------------- */
.faq-list { max-width: 900px; margin: 0 auto; display: grid; gap: 12px; }
.faq-item {
  border: 1px solid var(--line); border-radius: 14px;
  background: rgba(255, 255, 255, 0.025);
  transition: border-color .25s ease, background .25s ease;
}
.faq-item[open] { border-color: var(--line-strong); background: var(--glass); }
.faq-item summary {
  list-style: none; cursor: pointer;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 18px 22px;
  font-size: 16px; font-weight: 600; color: var(--text);
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+"; flex: none;
  width: 26px; height: 26px; line-height: 24px; text-align: center;
  border-radius: 8px; border: 1px solid var(--line-strong);
  color: var(--cyan); font-size: 17px; font-weight: 400;
  transition: background .25s ease, transform .25s ease;
}
.faq-item[open] summary::after { content: "−"; background: rgba(34, 211, 238, 0.12); }
.faq-item p {
  margin: 0; padding: 0 22px 20px;
  color: var(--text-mid); font-size: 14.8px; line-height: 1.75;
}

/* ---------------- 联系表单 ---------------- */
.contact-layout { display: grid; grid-template-columns: 1fr 1.25fr; gap: 28px; align-items: start; }
.contact-aside { display: grid; gap: 18px; }
.contact-card { padding: 24px; }
.contact-card h3 { font-size: 17.5px; }
.contact-card > p { color: var(--text-mid); font-size: 14.5px; margin-bottom: 12px; }
.contact-list { display: grid; gap: 8px; }
.contact-list li { position: relative; padding-left: 18px; font-size: 13.6px; color: var(--text-dim); }
.contact-list li::before {
  content: ""; position: absolute; left: 0; top: 9px;
  width: 6px; height: 6px; border-radius: 50%; background: var(--cyan);
}

.form-panel { padding: 28px; }
.form-tabs {
  display: flex; gap: 6px; padding: 5px; margin-bottom: 24px;
  background: rgba(255, 255, 255, 0.04); border: 1px solid var(--line); border-radius: 999px;
}
.form-tab {
  flex: 1; padding: 11px 16px; border: none; border-radius: 999px; cursor: pointer;
  background: transparent; color: var(--text-mid); font-size: 14.5px; font-weight: 600;
  transition: background .25s ease, color .25s ease;
}
.form-tab.is-active { background: var(--grad); color: #04121F; }

.lead-form { display: none; }
.lead-form.is-active { display: block; animation: fadeUp .35s ease both; }

.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.field { margin-bottom: 16px; }
.field label { display: block; margin-bottom: 7px; font-size: 13.8px; color: var(--text-mid); font-weight: 600; }
.field label i { color: #FF7A7A; font-style: normal; }

.field input, .field select, .field textarea {
  width: 100%; padding: 13px 15px;
  background: rgba(255, 255, 255, 0.035);
  border: 1px solid var(--line-strong); border-radius: var(--radius-sm);
  color: var(--text); font-size: 15px; font-family: inherit;
  transition: border-color .2s ease, background .2s ease, box-shadow .2s ease;
}
.field textarea { resize: vertical; min-height: 92px; line-height: 1.6; }
.field input::placeholder, .field textarea::placeholder { color: #5C6E88; }
.field select { appearance: none; -webkit-appearance: none; cursor: pointer; padding-right: 40px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23A9B7CE' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 14px center; background-size: 16px;
}
.field select option { background: #0E1B30; color: var(--text); }
.field input:focus, .field select:focus, .field textarea:focus {
  outline: none; border-color: rgba(34, 211, 238, 0.55);
  background: rgba(255, 255, 255, 0.06);
  box-shadow: 0 0 0 3px rgba(34, 211, 238, 0.12);
}
.field.has-error input, .field.has-error select, .field.has-error textarea { border-color: #FF7A7A; }

.err { display: none; margin: 6px 0 0; font-size: 12.8px; color: #FF8E8E; }
.err.is-visible { display: block; }

.check { display: flex; align-items: flex-start; gap: 10px; margin: 4px 0 6px; font-size: 13.5px; color: var(--text-dim); cursor: pointer; }
.check input { width: 17px; height: 17px; margin-top: 3px; accent-color: #22D3EE; flex: none; cursor: pointer; }
.check span { line-height: 1.55; }

.form-status { display: none; margin: 14px 0 0; font-size: 14px; }
.form-status.is-visible { display: block; }
.form-status.is-ok { color: #45E0C4; }
.form-status.is-fail { color: #FF8E8E; }

.form-tip { margin: 18px 0 0; font-size: 12.5px; color: var(--text-dim); }
.form-tip code {
  padding: 2px 7px; border-radius: 6px;
  background: rgba(255, 255, 255, 0.06); border: 1px solid var(--line);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 12px;
}

/* ---------------- 页脚 ---------------- */
.site-footer { border-top: 1px solid var(--line); padding: 64px 0 28px; background: rgba(10, 20, 36, 0.6); }
.footer-inner { display: grid; grid-template-columns: 1.1fr 2fr; gap: 48px; }
.footer-brand p { margin-top: 14px; color: var(--text-dim); font-size: 13.8px; }
.footer-nav { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
.footer-nav h4 { font-size: 14.5px; margin-bottom: 14px; color: var(--text); }
.footer-nav a, .footer-nav span {
  display: block; margin-bottom: 10px;
  font-size: 13.8px; color: var(--text-dim);
  transition: color .2s ease;
}
.footer-nav a:hover { color: var(--cyan); }
.footer-bottom {
  display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap;
  margin-top: 48px; padding-top: 22px; border-top: 1px solid var(--line);
}
.footer-bottom p { margin: 0; font-size: 13px; color: var(--text-dim); }
.footer-legal { display: flex; gap: 20px; }
.footer-legal span { cursor: default; }

/* ---------------- 回到顶部 ---------------- */
.back-to-top {
  position: fixed; right: 24px; bottom: 24px; z-index: 90;
  width: 46px; height: 46px; border-radius: 50%;
  display: inline-flex; align-items: center; justify-content: center;
  background: rgba(14, 27, 48, 0.9); border: 1px solid var(--line-strong);
  color: var(--cyan); cursor: pointer;
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  opacity: 0; visibility: hidden; transform: translateY(12px);
  transition: opacity .3s ease, transform .3s ease, visibility .3s ease;
}
.back-to-top.is-visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { border-color: rgba(34, 211, 238, 0.5); box-shadow: var(--shadow-glow); }

/* ---------------- 滚动出现动画 ---------------- */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .7s ease, transform .7s ease; }
.reveal.is-in { opacity: 1; transform: none; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: none; }
}

/* =========================================================
   响应式
   ========================================================= */

/* 平板 768 – 1199 */
@media (max-width: 1199px) {
  .container { padding: 0 20px; }
  .section { padding: 84px 0; }
  .hero { padding-top: calc(var(--header-h) + 56px); }
  .hero-inner { grid-template-columns: 1fr; gap: 44px; }
  .hero-copy { max-width: 720px; }
  .hero-visual { max-width: 720px; }
  .stats { margin-top: 56px; }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .tech-layout { grid-template-columns: 1fr; }
  .tech-panel { position: static; }
  .case-grid { grid-template-columns: repeat(2, 1fr); }
  .case-grid .case-card:last-child { grid-column: 1 / -1; }
  .about-layout { grid-template-columns: 1fr; }
  .contact-layout { grid-template-columns: 1fr; }
  .contact-aside { grid-template-columns: 1fr 1fr; }
  .footer-inner { grid-template-columns: 1fr; gap: 36px; }
  .float-chip { font-size: 12.5px; padding: 8px 13px; }
  .chip-a { left: 8px; }
  .chip-b { right: 8px; }
}

/* 移动 < 768 */
@media (max-width: 767px) {
  body { font-size: 15.5px; }
  .container { padding: 0 18px; }
  .section { padding: 66px 0; }
  .section-head { margin-bottom: 38px; }
  .hide-sm { display: none; }

  .nav-toggle { display: block; }
  .nav {
    position: fixed; inset: var(--header-h) 0 auto 0;
    flex-direction: column; align-items: stretch; gap: 4px;
    padding: 14px 18px 22px;
    background: #070D1B;
    border-bottom: 1px solid var(--line);
    box-shadow: 0 24px 40px -24px rgba(0, 0, 0, 0.9);
    transform: translateY(-14px); opacity: 0; visibility: hidden;
    transition: transform .28s ease, opacity .28s ease, visibility .28s ease;
    max-height: calc(100vh - var(--header-h)); overflow-y: auto;
  }
  .nav.is-open { transform: none; opacity: 1; visibility: visible; }
  .nav > a { padding: 13px 14px; font-size: 16px; border-radius: 10px; }
  .nav > a.nav-cta { margin: 10px 0 0; text-align: center; }

  .hero { padding-top: calc(var(--header-h) + 40px); padding-bottom: 48px; }
  .hero-inner { gap: 32px; }
  .hero-actions { margin: 22px 0; }
  .hero-actions .btn { width: 100%; }
  .hero-trust { gap: 8px 16px; }
  .hero-trust li { font-size: 13px; }
  .float-chip { display: none; }

  .stats { grid-template-columns: repeat(2, 1fr); padding: 22px 12px; margin-top: 44px; gap: 4px 0; }
  .stat { padding: 10px 12px; border-right: none; }
  .stat:nth-child(odd) { border-right: 1px solid var(--line); }
  .stat:nth-child(-n+2) { padding-bottom: 16px; }
  .stat:nth-child(n+3) { padding-top: 16px; }

  .feature-grid, .scene-grid, .case-grid { grid-template-columns: 1fr; }
  .card { padding: 22px; }
  .scene-grid { gap: 18px; }
  .scene-media { aspect-ratio: 16 / 9; }
  .scene-body { padding: 20px 20px 22px; }

  .tech-list li { padding: 16px 4px; gap: 14px; flex-direction: column; gap: 8px; }
  .tech-idx { padding-top: 0; }
  .tech-panel, .about-panel, .form-panel { padding: 22px; }

  .about-grid { grid-template-columns: 1fr; }
  .contact-aside { grid-template-columns: 1fr; }

  .faq-item summary { padding: 16px 18px; font-size: 15px; gap: 12px; }
  .faq-item p { padding: 0 18px 18px; font-size: 14.2px; }

  .field-row { grid-template-columns: 1fr; gap: 0; }
  .form-tab { font-size: 13.5px; padding: 10px 8px; }

  .footer-nav { grid-template-columns: 1fr 1fr; gap: 22px; }
  .footer-bottom { flex-direction: column; align-items: flex-start; gap: 10px; }
  .footer-legal { flex-wrap: wrap; gap: 14px; }

  .back-to-top { right: 16px; bottom: 16px; width: 42px; height: 42px; }
}

/* 小屏微调 */
@media (max-width: 380px) {
  .hero-actions .btn { padding: 13px 18px; font-size: 14.5px; }
  .section-head h2 { font-size: 24px; }
}

/* 降低动效偏好 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .001ms !important; animation-iteration-count: 1 !important; transition-duration: .001ms !important; }
  .reveal { opacity: 1; transform: none; }
}

/* 打印 */
@media print {
  .site-header, .back-to-top, .hero-bg, .float-chip { display: none !important; }
  body { background: #fff; color: #000; }
}