/* ============================================================================
   云瞰 YUNKAN · 宣传官网样式
   方案 A「云端科技蓝」  主色 #014DB2  亮蓝 #1E6FE8  深蓝 #013A85
   零外部依赖：不使用任何 CDN、网络字体或外部图片。
   ============================================================================ */

:root {
  --brand: #014DB2;
  --brand-2: #1E6FE8;
  --brand-deep: #013A85;
  --brand-soft: #E8F0FE;
  --brand-line: #CFE0F7;

  --ink: #0F172A;
  --ink-2: #5A6B85;
  --ink-3: #64748B;
  --ink-4: #8A97AD;

  --white: #FFFFFF;
  --bg: #F7F8FA;
  --bg-2: #EEF3FA;
  --line: #E4EAF3;
  --navy: #0B1B33;

  --ok: #10B981;
  --warn: #F59E0B;
  --danger: #EF4444;

  --grad: linear-gradient(135deg, #013A85 0%, #014DB2 52%, #1E6FE8 100%);
  --grad-soft: linear-gradient(180deg, #EAF1FB 0%, #F7F8FA 100%);

  --shadow-sm: 0 4px 16px rgba(1, 77, 178, .08);
  --shadow-md: 0 10px 28px rgba(1, 77, 178, .12);
  --shadow-lg: 0 20px 50px rgba(1, 20, 60, .28);

  --r-sm: 8px;
  --r-md: 12px;
  --r-lg: 16px;

  --font: 'PingFang SC', 'HarmonyOS Sans SC', 'Microsoft YaHei', 'Source Han Sans SC', 'Hiragino Sans GB', sans-serif;
  --font-num: Inter, 'Segoe UI', system-ui, -apple-system, sans-serif;

  --wrap: 1160px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-2);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1, h2, h3, b { color: var(--ink); }
h1, h2, h3 { margin: 0; line-height: 1.3; }
h1 { font-size: clamp(30px, 4.2vw, 50px); font-weight: 800; letter-spacing: -1px; line-height: 1.16; }
h2 { font-size: clamp(23px, 2.5vw, 34px); font-weight: 700; letter-spacing: -.6px; }
h3 { font-size: 17px; font-weight: 600; letter-spacing: -.2px; }
p { margin: 0; }
a { color: inherit; text-decoration: none; }
ul, ol { margin: 0; padding: 0; list-style: none; }
svg { display: block; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 24px; }
.wrap-narrow { max-width: 840px; }

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 999;
  background: var(--brand); 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;
  height: 42px; padding: 0 20px; border: 1px solid transparent; border-radius: var(--r-sm);
  font-size: 14px; font-weight: 600; font-family: inherit; cursor: pointer;
  transition: background .18s ease, color .18s ease, border-color .18s ease, box-shadow .18s ease, transform .18s ease;
  white-space: nowrap;
}
.btn-sm { height: 36px; padding: 0 16px; font-size: 13.5px; }
.btn-lg { height: 48px; padding: 0 26px; font-size: 15px; }

.btn-primary { background: var(--grad); color: #fff; box-shadow: 0 6px 18px rgba(1, 77, 178, .28); }
.btn-primary:hover { box-shadow: 0 10px 26px rgba(1, 77, 178, .34); transform: translateY(-1px); }

.btn-ghost { background: #fff; color: var(--brand); border-color: var(--brand-line); }
.btn-ghost:hover { background: var(--brand-soft); border-color: var(--brand-2); }

/* ============================ 顶栏 ============================ */
.topnav {
  position: sticky; top: 0; z-index: 60;
  background: rgba(255, 255, 255, .86);
  backdrop-filter: saturate(160%) blur(12px);
  -webkit-backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.topnav-inner { display: flex; align-items: center; gap: 28px; height: 66px; }

.brand { display: flex; align-items: center; gap: 10px; flex: none; }
.brand-mark { width: 34px; height: 34px; flex: none; }
.brand-mark svg { width: 100%; height: 100%; }
.brand-mark.sm { width: 38px; height: 38px; }
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-text b { font-size: 16px; font-weight: 700; letter-spacing: -.2px; }
.brand-text i {
  font-style: normal; font-size: 10.5px; letter-spacing: 2.2px;
  color: var(--ink-4); font-family: var(--font-num); font-weight: 600;
}

.nav { display: flex; align-items: center; gap: 26px; margin-left: auto; }
.nav a { font-size: 14px; color: var(--ink-2); font-weight: 500; position: relative; padding: 4px 0; }
.nav a::after {
  content: ''; position: absolute; left: 0; right: 100%; bottom: 0; height: 2px;
  background: var(--brand); border-radius: 2px; transition: right .2s ease;
}
.nav a:hover { color: var(--ink); }
.nav a:hover::after { right: 0; }

.topnav-actions { display: flex; align-items: center; gap: 10px; flex: none; }
.nav-toggle {
  display: none; width: 40px; height: 40px; border: 1px solid var(--line);
  border-radius: var(--r-sm); background: #fff; color: var(--ink); cursor: pointer;
  align-items: center; justify-content: center;
}
.nav-toggle svg { width: 20px; height: 20px; }

/* ============================ Hero ============================ */
.hero { position: relative; overflow: hidden; background: var(--grad); color: #fff; }
.hero-bg { position: absolute; inset: 0; pointer-events: none; }
.hero-bg::before {
  content: ''; position: absolute; inset: 0;
  background:
    radial-gradient(900px 420px at 12% 8%, rgba(56, 189, 248, .30), transparent 62%),
    radial-gradient(700px 460px at 88% 96%, rgba(124, 58, 237, .16), transparent 66%);
}
/* 文字区压暗遮罩：保证白色文字在渐变最亮处也满足对比度要求 */
.hero-bg::after {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(100deg, rgba(1, 20, 60, .40) 0%, rgba(1, 20, 60, .18) 52%, rgba(1, 20, 60, .04) 100%);
}
.hero-inner {
  position: relative; z-index: 1;
  display: grid; grid-template-columns: 1.02fr .98fr; gap: 56px; align-items: center;
  padding-top: 76px; padding-bottom: 84px;
}
.hero-copy h1 { color: #fff; }
.hero-sub { margin-top: 20px; font-size: 16px; line-height: 1.85; color: rgba(255, 255, 255, .88); max-width: 32em; }
.hero-cta { display: flex; gap: 12px; margin-top: 30px; flex-wrap: wrap; }
.hero .btn-primary { background: #fff; color: var(--brand); box-shadow: 0 10px 28px rgba(0, 20, 60, .3); }
.hero .btn-primary:hover { background: #F2F7FF; }
.hero .btn-ghost { background: rgba(255, 255, 255, .12); color: #fff; border-color: rgba(255, 255, 255, .42); }
.hero .btn-ghost:hover { background: rgba(255, 255, 255, .2); border-color: rgba(255, 255, 255, .7); }

.pill {
  display: inline-flex; align-items: center; gap: 8px; height: 32px; padding: 0 14px;
  border-radius: 999px; background: rgba(255, 255, 255, .14); border: 1px solid rgba(255, 255, 255, .3);
  font-size: 12.5px; font-weight: 600; color: #fff; margin-bottom: 20px;
}
.pill svg { width: 15px; height: 15px; }

.hero-trust { display: flex; flex-wrap: wrap; gap: 10px 24px; margin-top: 30px; }
.hero-trust li { display: flex; align-items: center; gap: 7px; font-size: 13.5px; color: rgba(255, 255, 255, .9); }
.hero-trust svg { width: 16px; height: 16px; color: #7FE3B8; flex: none; }

.hero-visual { position: relative; }
.hv-frame {
  background: #fff; border-radius: var(--r-lg); padding: 12px;
  box-shadow: var(--shadow-lg);
}
.hv-bar { display: flex; align-items: center; gap: 6px; padding: 2px 6px 12px; }
.hv-dot { width: 9px; height: 9px; border-radius: 50%; background: #DDE5F0; }
.hv-bar-title { font-size: 12px; font-weight: 600; color: var(--ink-2); margin-left: 8px; }
.hv-live { margin-left: auto; display: inline-flex; align-items: center; gap: 5px; font-size: 11px; font-weight: 700; color: var(--ok); letter-spacing: .06em; }
.hv-live i { width: 7px; height: 7px; border-radius: 50%; background: var(--ok); display: block; }

.hv-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.hv-tile { position: relative; border-radius: var(--r-sm); overflow: hidden; aspect-ratio: 16 / 9; background: #0B1B33; }
.hv-tile svg { width: 100%; height: 100%; }
.hv-tag {
  position: absolute; left: 8px; bottom: 7px; font-size: 11px; font-weight: 600; color: #fff;
  background: rgba(1, 20, 60, .62); border-radius: 4px; padding: 2px 7px;
}
.hv-tag-warn { background: rgba(239, 68, 68, .82); }

.hv-foot {
  display: flex; justify-content: space-between; padding: 12px 6px 2px;
  font-size: 11.5px; color: var(--ink-3); font-family: var(--font-num);
}

.hv-cloud {
  position: absolute; left: -22px; top: -22px; width: 62px; height: 62px;
  border-radius: 18px; box-shadow: 0 12px 30px rgba(0, 20, 60, .34);
}
.hv-cloud svg { width: 100%; height: 100%; }

/* ============================ 能力条 ============================ */
.strip { background: var(--white); border-bottom: 1px solid var(--line); }
.strip-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 28px; padding: 34px 24px; }
.strip-item b { display: block; font-size: 15px; font-weight: 600; margin-bottom: 4px; }
.strip-item b::before {
  content: ''; display: inline-block; width: 6px; height: 6px; border-radius: 50%;
  background: var(--brand); margin-right: 8px; vertical-align: 2px;
}
.strip-item span { font-size: 13.5px; color: var(--ink-3); line-height: 1.6; }

/* ============================ 区块 ============================ */
.sec { padding: 84px 0; }
.sec-alt { background: var(--bg); }
.sec-head { max-width: 720px; margin-bottom: 46px; }
.eyebrow {
  display: inline-block; font-size: 12.5px; font-weight: 700; letter-spacing: .14em;
  color: var(--brand); margin-bottom: 12px;
}
.eyebrow-light { color: rgba(255, 255, 255, .82); }
.sec-sub { margin-top: 14px; font-size: 15px; line-height: 1.85; color: var(--ink-2); }

/* ============================ 能力卡 ============================ */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--r-md);
  padding: 26px 24px; box-shadow: var(--shadow-sm);
  transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: var(--brand-line); }
.card-ico {
  display: grid; place-items: center; width: 44px; height: 44px; border-radius: var(--r-sm);
  background: var(--brand-soft); color: var(--brand); margin-bottom: 18px;
}
.card-ico svg { width: 22px; height: 22px; }
.card p { margin-top: 10px; font-size: 14px; line-height: 1.8; color: var(--ink-2); }

/* ============================ 架构 ============================ */
.arch { display: grid; gap: 0; max-width: 880px; }
.arch-tier {
  display: grid; grid-template-columns: 132px 1fr; gap: 20px; align-items: center;
  background: #fff; border: 1px solid var(--line); border-radius: var(--r-md);
  padding: 20px 22px; box-shadow: var(--shadow-sm);
}
.arch-label { display: flex; align-items: center; gap: 9px; font-size: 14px; font-weight: 600; color: var(--ink); }
.arch-no {
  display: grid; place-items: center; width: 26px; height: 26px; border-radius: 7px;
  background: var(--grad); color: #fff; font-size: 11.5px; font-weight: 700; font-family: var(--font-num);
}
.arch-box { display: flex; gap: 14px; align-items: flex-start; }
.arch-box > svg { width: 24px; height: 24px; flex: none; margin-top: 4px; color: var(--brand); }
.arch-box b { font-size: 15px; font-weight: 600; }
.arch-box p { margin-top: 5px; font-size: 13.5px; line-height: 1.75; color: var(--ink-3); }

.arch-arrow { display: grid; justify-items: center; gap: 2px; padding: 8px 0; color: var(--brand-2); }
.arch-arrow svg { width: 20px; height: 20px; }
.arch-arrow span { font-size: 11.5px; color: var(--ink-4); letter-spacing: .04em; }

.arch-notes { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin-top: 44px; }
.note { background: #fff; border: 1px solid var(--line); border-left: 3px solid var(--brand); border-radius: var(--r-sm); padding: 20px 22px; }
.note p { margin-top: 8px; font-size: 13.5px; line-height: 1.8; color: var(--ink-3); }

/* ============================ 行业 ============================ */
.ind-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.ind {
  background: #fff; border: 1px solid var(--line); border-radius: var(--r-md);
  padding: 24px; box-shadow: var(--shadow-sm); transition: transform .2s ease, box-shadow .2s ease;
}
.ind:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.ind-ico { display: grid; place-items: center; width: 40px; height: 40px; border-radius: var(--r-sm); background: var(--grad-soft); color: var(--brand); border: 1px solid var(--brand-line); margin-bottom: 16px; }
.ind-ico svg { width: 21px; height: 21px; }
.ind p { margin-top: 9px; font-size: 13.5px; line-height: 1.78; color: var(--ink-3); }

/* ============================ 步骤 ============================ */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; counter-reset: s; }
.step { background: #fff; border: 1px solid var(--line); border-radius: var(--r-md); padding: 26px 22px; box-shadow: var(--shadow-sm); position: relative; }
.step::after {
  content: ''; position: absolute; top: 40px; right: -20px; width: 20px; height: 1px;
  background: var(--brand-line);
}
.step:last-child::after { display: none; }
.step-no {
  display: grid; place-items: center; width: 32px; height: 32px; border-radius: 50%;
  background: var(--brand-soft); color: var(--brand); border: 1px solid var(--brand-line);
  font-size: 14px; font-weight: 700; font-family: var(--font-num); margin-bottom: 16px;
}
.step p { margin-top: 9px; font-size: 13.5px; line-height: 1.8; color: var(--ink-3); }

/* ============================ 规格表 ============================ */
.spec-wrap { background: #fff; border: 1px solid var(--line); border-radius: var(--r-md); overflow: hidden; box-shadow: var(--shadow-sm); }
.spec-table { width: 100%; border-collapse: collapse; }
.spec-table th, .spec-table td { text-align: left; padding: 18px 24px; vertical-align: top; border-bottom: 1px solid var(--line); }
.spec-table tr:last-child th, .spec-table tr:last-child td { border-bottom: 0; }
.spec-table th {
  width: 168px; font-size: 14px; font-weight: 600; color: var(--ink);
  background: var(--bg); white-space: nowrap;
}
.spec-table td { font-size: 14px; line-height: 1.8; color: var(--ink-2); }

/* ============================ FAQ ============================ */
.faq { display: grid; gap: 12px; }
.qa {
  background: #fff; border: 1px solid var(--line); border-radius: var(--r-md);
  padding: 0 22px; box-shadow: var(--shadow-sm); transition: border-color .2s ease;
}
.qa[open] { border-color: var(--brand-line); }
.qa summary {
  list-style: none; cursor: pointer; padding: 18px 0; font-size: 15px;
  font-weight: 600; color: var(--ink); display: flex; align-items: center; gap: 12px;
}
.qa summary::-webkit-details-marker { display: none; }
.qa summary::before {
  content: ''; width: 18px; height: 18px; flex: none; border-radius: 5px;
  background: var(--brand-soft) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23014DB2' stroke-width='3' stroke-linecap='round'%3E%3Cpath d='M12 6v12M6 12h12'/%3E%3C/svg%3E") center / 12px no-repeat;
  transition: transform .2s ease;
}
.qa[open] summary::before { transform: rotate(45deg); }
.qa p { padding: 0 0 20px 30px; font-size: 14px; line-height: 1.85; color: var(--ink-2); }

/* ============================ 联系 ============================ */
.contact { padding-top: 20px; }
.contact-card {
  display: grid; grid-template-columns: 1.15fr .85fr; gap: 48px; align-items: center;
  background: var(--grad); border-radius: var(--r-lg); padding: 52px 48px;
  box-shadow: 0 24px 60px rgba(1, 20, 60, .26); color: #fff; position: relative; overflow: hidden;
}
.contact-card::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(100deg, rgba(1, 20, 60, .34) 0%, rgba(1, 20, 60, .12) 55%, rgba(1, 20, 60, .02) 100%);
  pointer-events: none;
}
.contact-copy, .contact-list { position: relative; z-index: 1; }
.contact-copy h2 { color: #fff; }
.contact-copy p { margin-top: 14px; font-size: 15px; line-height: 1.85; color: rgba(255, 255, 255, .88); }

.contact-list { display: grid; gap: 12px; }
.contact-list li {
  display: flex; align-items: center; gap: 14px;
  background: rgba(255, 255, 255, .1); border: 1px solid rgba(255, 255, 255, .24);
  border-radius: var(--r-md); padding: 14px 18px;
}
.ci { display: grid; place-items: center; width: 36px; height: 36px; border-radius: 10px; background: rgba(255, 255, 255, .16); flex: none; }
.ci svg { width: 18px; height: 18px; color: #fff; }
.contact-list b { display: block; font-size: 12px; font-weight: 600; color: rgba(255, 255, 255, .82); margin-bottom: 1px; }
.contact-list span { font-size: 14.5px; font-weight: 600; color: #fff; font-family: var(--font-num); }

/* ============================ 页脚 ============================ */
.footer { background: var(--navy); color: rgba(255, 255, 255, .74); margin-top: 84px; }
.footer-inner { display: grid; grid-template-columns: 1.1fr 1fr; gap: 32px 48px; padding: 48px 24px 40px; align-items: start; }
.footer-brand { display: flex; align-items: center; gap: 12px; }
.footer-brand b { display: block; font-size: 15px; font-weight: 600; color: #fff; }
.footer-brand span { font-size: 12.5px; color: rgba(255, 255, 255, .6); }
.footer-nav { display: flex; flex-wrap: wrap; gap: 10px 22px; justify-content: flex-end; padding-top: 6px; }
.footer-nav a { font-size: 13.5px; color: rgba(255, 255, 255, .72); }
.footer-nav a:hover { color: #fff; }
/* 页脚快速入口：管理后台 / 家长端（系统两端登录入口） */
.footer-entries {
  grid-column: 1 / -1; display: flex; flex-wrap: wrap; align-items: center; gap: 12px 14px;
  padding-top: 26px;
}
.fe-label { font-size: 12.5px; color: rgba(255, 255, 255, .62); margin-right: 2px; }
.fe-btn {
  display: inline-flex; align-items: center; gap: 9px;
  padding: 11px 20px; border-radius: 10px;
  border: 1px solid rgba(255, 255, 255, .26);
  background: rgba(255, 255, 255, .08);
  color: #fff; font-size: 13.5px; font-weight: 600;
  transition: background .16s ease, border-color .16s ease, transform .16s ease;
}
.fe-btn:hover { background: rgba(255, 255, 255, .17); border-color: rgba(255, 255, 255, .45); transform: translateY(-1px); }
.fe-btn:focus-visible { outline: 2px solid rgba(255, 255, 255, .8); outline-offset: 2px; }
.fe-btn svg { width: 16px; height: 16px; flex: none; }
.fe-note { font-size: 12px; color: rgba(255, 255, 255, .5); margin-left: 2px; }
.footer-meta {
  grid-column: 1 / -1; display: flex; flex-wrap: wrap; gap: 8px 24px; justify-content: space-between;
  padding-top: 24px; border-top: 1px solid rgba(255, 255, 255, .12); font-size: 12.5px; color: rgba(255, 255, 255, .55);
}

/* ============================ 响应式 ============================ */
@media (max-width: 1080px) {
  .hero-inner { grid-template-columns: 1fr; gap: 48px; padding-top: 60px; padding-bottom: 68px; }
  .hero-visual { max-width: 620px; }
  .cards, .ind-grid { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .step::after { display: none; }
  .contact-card { grid-template-columns: 1fr; gap: 34px; padding: 44px 36px; }
}

@media (max-width: 980px) {
  .nav {
    position: absolute; top: 66px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: #fff; border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow-md); padding: 6px 24px 14px;
    display: none;
  }
  .nav.open { display: flex; }
  .nav a { padding: 12px 0; border-bottom: 1px solid var(--line); font-size: 15px; }
  .nav a:last-child { border-bottom: 0; }
  .nav a::after { display: none; }
  .nav-toggle { display: inline-flex; }
  .topnav-inner { gap: 12px; }
  .topnav-actions { margin-left: auto; }
  .topnav-actions .btn-ghost { display: none; }
}

@media (max-width: 760px) {
  body { font-size: 14.5px; }
  .sec { padding: 60px 0; }
  .strip-grid { grid-template-columns: repeat(2, 1fr); gap: 20px; }
  .cards, .ind-grid, .steps, .arch-notes { grid-template-columns: 1fr; }
  .arch-tier { grid-template-columns: 1fr; gap: 12px; }
  .arch-label { padding-bottom: 2px; }
  .spec-table th, .spec-table td { display: block; width: auto; }
  .spec-table th { padding: 14px 20px 4px; background: transparent; }
  .spec-table td { padding: 0 20px 16px; border-bottom: 1px solid var(--line); }
  .hero-trust { gap: 8px 18px; }
  .hv-cloud { width: 50px; height: 50px; left: -10px; top: -14px; }
  .contact-card { padding: 34px 24px; border-radius: var(--r-md); }
  .footer-inner { grid-template-columns: 1fr; padding: 40px 24px 32px; }
  .footer-nav { justify-content: flex-start; }
  .brand-text i { letter-spacing: 1.6px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}