/* ═══ 知衡 AI · 产品官网 · 高亮白 + AI 科技风 ═══ */
:root {
  /* 品牌色：深蓝渐变 */
  --brand: #1e40af;
  --brand-2: #1e3a8a;
  --brand-dark: #172554;
  --accent: #1e3a8a;
  --accent-2: #38bdf8;
  --brand-soft: #dbeafe;
  --ok: #059669;    --ok-bg: #ecfdf5;
  --warn: #d97706;
  --err: #dc2626;
  --bg: #f5f8fc;
  --card: #ffffff;
  --line: #dbe3f0;
  --text: #0b1526;
  --text-2: #1e293b;
  --text-3: #51607a;
  --muted: #94a3b8;
  --shadow: 0 1px 2px rgba(11,21,38,.06), 0 4px 16px rgba(11,21,38,.08);
  --shadow-lg: 0 8px 32px rgba(30,64,175,.20), 0 2px 8px rgba(11,21,38,.06);
  --glow: 0 0 22px rgba(30,64,175,.28);
  --radius: 16px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text); background: var(--bg); font-size: 15px; line-height: 1.6;
}
a { color: inherit; }
.grad-text {
  background: linear-gradient(90deg, var(--brand), var(--accent-2));
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.muted { color: var(--text-3); }

/* 页面下方浅色区柔和光晕 */
body { background: var(--bg); }
body > * { position: relative; z-index: 1; }

.container { max-width: 1120px; margin: 0 auto; padding: 0 24px; }
.container.narrow { max-width: 760px; }

/* ═══ 按钮 ═══ */
.btn-primary {
  display: inline-block; background: linear-gradient(135deg, var(--brand), var(--accent));
  color: #fff; border: none; border-radius: 12px; font-size: 14px; font-weight: 600;
  padding: 12px 28px; cursor: pointer; text-decoration: none;
  box-shadow: 0 4px 16px rgba(30,64,175,.38); transition: all .18s;
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 28px rgba(30,64,175,.5); }
.btn-ghost {
  display: inline-block; background: var(--card); border: 1px solid var(--line);
  color: var(--text-2); border-radius: 12px; font-size: 14px; font-weight: 500;
  padding: 12px 28px; cursor: pointer; text-decoration: none; transition: all .18s;
}
.btn-ghost:hover { border-color: var(--brand); color: var(--brand); background: var(--brand-soft); }
.btn-lg { padding: 14px 34px; font-size: 15px; }
.btn-block { display: block; text-align: center; width: 100%; }
button.ghost { background: #fff; border: 1px solid var(--line); color: var(--text-3); border-radius: 8px; padding: 8px 16px; font-size: 12.5px; cursor: pointer; }
button.ghost:hover { color: var(--brand); border-color: var(--brand); background: var(--brand-soft); }
button.ghost.sm { padding: 5px 12px; font-size: 11.5px; }

/* ═══ 导航（深色首屏之上，深色毛玻璃）═══ */
#nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(10,20,45,.72); backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(56,189,248,.14);
}
.nav-inner { max-width: 1120px; margin: 0 auto; padding: 0 24px; height: 64px; display: flex; align-items: center; gap: 20px; }
.logo { display: flex; align-items: center; gap: 10px; text-decoration: none; }
.logo-mark {
  background: linear-gradient(135deg, var(--accent-2), #60a5fa);
  color: #fff; font-weight: 700; font-size: 15px; letter-spacing: 1px;
  padding: 5px 12px; border-radius: 9px;
  box-shadow: 0 0 18px rgba(56,189,248,.45);
}
.logo-mark.sm { font-size: 13px; padding: 4px 10px; border-radius: 7px; }
.logo-text { font-size: 14px; font-weight: 600; color: #cbd5e1; }
.nav-links { flex: 1; display: flex; gap: 6px; justify-content: center; flex-wrap: wrap; }
.nav-links a {
  text-decoration: none; color: #94a3b8; font-size: 13.5px; font-weight: 500;
  padding: 8px 14px; border-radius: 9px; transition: all .15s;
}
.nav-links a:hover { background: rgba(56,189,248,.10); color: #e2e8f0; }
.nav-links a.active { background: rgba(56,189,248,.14); color: #7dd3fc; font-weight: 600; }
.btn-light {
  display: inline-block; background: linear-gradient(135deg, var(--accent-2), #60a5fa);
  color: #061426; font-weight: 700; border: none; border-radius: 10px;
  font-size: 13px; padding: 9px 20px; cursor: pointer; text-decoration: none;
  box-shadow: 0 4px 16px rgba(56,189,248,.4); transition: all .18s;
}
.btn-light:hover { transform: translateY(-1px); box-shadow: 0 6px 24px rgba(56,189,248,.55); }
.nav-cta { padding: 9px 22px; }

/* ═══ Hero（深色科技蓝）═══ */
.hero {
  position: relative;
  padding: 84px 0 0; overflow: hidden;
  background:
    radial-gradient(ellipse 1000px 520px at 22% -6%, rgba(30,64,175,.55), transparent 62%),
    radial-gradient(ellipse 760px 480px at 92% 2%, rgba(14,116,144,.45), transparent 60%),
    linear-gradient(180deg, #0a1428 0%, #0e1b3a 52%, #0a1428 100%);
  color: #fff;
  border-bottom: 1px solid rgba(56,189,248,.15);
}
/* 光斑：随滚动漂移 */
.hero-orb { position: absolute; z-index: 0; border-radius: 50%; pointer-events: none; filter: blur(70px); will-change: transform; }
.hero-orb-1 { width: 460px; height: 460px; top: -140px; left: 8%; background: rgba(37,99,235,.4); }
.hero-orb-2 { width: 380px; height: 380px; top: 60px; right: 6%; background: rgba(56,189,248,.32); }
/* 顶部流光带 */
.hero-band {
  position: absolute; top: 0; left: 0; right: 0; height: 3px; z-index: 1;
  background: linear-gradient(90deg, transparent, #38bdf8 30%, #60a5fa 50%, #38bdf8 70%, transparent);
  background-size: 200% 100%;
  animation: bandSlide 4s linear infinite;
}
@keyframes bandSlide { to { background-position: 200% 0; } }

.hero-inner { position: relative; z-index: 2; display: grid; grid-template-columns: 1.05fr .95fr; gap: 48px; align-items: center; }
.hero-copy h1 { font-size: 54px; line-height: 1.12; font-weight: 800; margin: 0 0 20px; letter-spacing: 1px; color: #fff; }
/* 纯 CSS 入场：即使 JS 未执行也保证首屏可见 + 深色科技风 */
.hero-copy .hero-badge, .hero-copy h1, .hero-copy .hero-sub, .hero-copy .hero-actions, .hero-copy .hero-trust, .hero-visual {
  animation: heroIn .8s cubic-bezier(.2,.7,.3,1) both;
}
.hero-copy h1 { animation-delay: .1s; }
.hero-copy .hero-sub { animation-delay: .2s; }
.hero-copy .hero-actions { animation-delay: .3s; }
.hero-copy .hero-trust { animation-delay: .4s; }
.hero-visual { animation-delay: .25s; }
@keyframes heroIn { from { opacity: 0; transform: translateY(30px); } to { opacity: 1; transform: none; } }
.hero-copy .grad-text {
  background: linear-gradient(90deg, #60a5fa, #38bdf8, #67e8f9);
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.hero-badge {
  display: inline-block; font-size: 12.5px; font-weight: 600; color: #7dd3fc;
  background: rgba(56,189,248,.10); border: 1px solid rgba(56,189,248,.35);
  padding: 6px 14px; border-radius: 20px; margin-bottom: 22px;
}
.hero-sub { font-size: 16.5px; color: #b6c6e0; margin: 0 0 30px; max-width: 480px; }
.hero-sub b { color: #e2e8f0; }
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 32px; }
.btn-hero {
  display: inline-block; background: linear-gradient(135deg, #38bdf8, #60a5fa);
  color: #061426; font-weight: 700; border: none; border-radius: 12px;
  font-size: 15px; padding: 14px 32px; cursor: pointer; text-decoration: none;
  box-shadow: 0 6px 24px rgba(56,189,248,.4); transition: all .18s;
}
.btn-hero:hover { transform: translateY(-2px); box-shadow: 0 10px 32px rgba(56,189,248,.55); }
.btn-hero-ghost {
  display: inline-block; background: rgba(255,255,255,.06); border: 1px solid rgba(148,163,184,.35);
  color: #e2e8f0; font-weight: 600; border-radius: 12px;
  font-size: 15px; padding: 14px 32px; cursor: pointer; text-decoration: none; transition: all .18s;
}
.btn-hero-ghost:hover { border-color: #38bdf8; color: #7dd3fc; background: rgba(56,189,248,.10); }
.hero-trust { font-size: 13px; color: #64748b; }
.hero-trust b { color: #cbd5e1; }

/* 模拟对话窗（深色玻璃拟态）*/
.hero-visual { position: relative; }
.mock-chat {
  position: relative;
  background: rgba(255,255,255,.05); border: 1px solid rgba(148,163,184,.25);
  border-radius: var(--radius); backdrop-filter: blur(10px);
  box-shadow: 0 24px 64px rgba(2,8,23,.6), 0 0 0 1px rgba(56,189,248,.08);
  overflow: hidden;
  animation: floaty 5.5s ease-in-out infinite;
}
@keyframes floaty { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-12px); } }
.mock-glow {
  position: absolute; inset: -1px; border-radius: var(--radius); pointer-events: none;
  background: radial-gradient(ellipse 300px 160px at 85% 10%, rgba(56,189,248,.18), transparent 70%);
}
.mock-bar {
  display: flex; align-items: center; gap: 6px; padding: 13px 18px;
  background: rgba(255,255,255,.05); border-bottom: 1px solid rgba(148,163,184,.18);
}
.mock-bar i { width: 9px; height: 9px; border-radius: 50%; background: rgba(148,163,184,.4); }
.mock-bar i:first-child { background: #38bdf8; box-shadow: 0 0 8px #38bdf8; }
.mock-bar span { margin-left: 8px; font-size: 12px; color: #94a3b8; letter-spacing: .5px; }
.mock-body { padding: 22px; display: flex; flex-direction: column; gap: 12px; }
.m-user, .m-ai { max-width: 84%; padding: 12px 16px; border-radius: 13px; font-size: 13.5px; line-height: 1.6; }
.m-user {
  align-self: flex-end; color: #eaf2ff; border-bottom-right-radius: 4px;
  background: linear-gradient(135deg, #1d4ed8, #2563eb);
  box-shadow: 0 6px 20px rgba(29,78,216,.45);
}
.m-ai {
  align-self: flex-start; color: #dbe7f8; border-bottom-left-radius: 4px;
  background: rgba(30,58,138,.35); border: 1px solid rgba(96,165,250,.28);
}
.m-ai-tag { font-size: 11px; font-weight: 700; color: #7dd3fc; margin-bottom: 5px; letter-spacing: 1px; }
.m-cite { display: inline-block; margin-top: 8px; font-size: 11px; color: #67e8f9; background: rgba(56,189,248,.14); padding: 2px 10px; border-radius: 10px; }
.m-chips { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 9px; }
.m-chips span {
  font-size: 11px; font-weight: 600; color: #bae6fd;
  background: rgba(37,99,235,.4); border: 1px solid rgba(96,165,250,.4);
  padding: 3px 10px; border-radius: 11px;
}

/* 数据条（深蓝渐变小卡）*/
.metrics { position: relative; z-index: 2; padding: 56px 0 72px; }
.metrics-inner { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.metric-card {
  background: linear-gradient(150deg, rgba(30,58,138,.55), rgba(15,23,42,.35));
  border: 1px solid rgba(96,165,250,.22); border-radius: var(--radius);
  padding: 26px 20px; text-align: center;
  backdrop-filter: blur(6px);
}
.metric-card b {
  display: block; font-size: 34px; font-weight: 800; line-height: 1.1; margin-bottom: 6px;
  background: linear-gradient(90deg, #93c5fd, #38bdf8, #67e8f9);
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.metric-card span { font-size: 13px; color: #94a3b8; letter-spacing: .5px; }

/* ═══ 通用 section ═══ */
.section { padding: 72px 0; }
.section-alt { background: rgba(255,255,255,.6); }
.sec-head { text-align: center; max-width: 620px; margin: 0 auto 44px; }
.sec-tag {
  display: inline-block; font-size: 12px; font-weight: 700; letter-spacing: 1.5px;
  color: var(--brand); background: var(--brand-soft); border: 1px solid rgba(30,64,175,.25);
  padding: 4px 14px; border-radius: 14px; margin-bottom: 14px;
}
.sec-head h2 { font-size: 32px; font-weight: 800; margin: 0 0 10px; letter-spacing: .5px; }
.sec-head p { color: var(--text-3); margin: 0; }

/* 能力卡片 */
.feature-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.f-card {
  position: relative; background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 26px 28px; box-shadow: var(--shadow);
  transition: all .2s; overflow: hidden;
}
.f-card::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--brand), var(--accent-2));
  opacity: 0; transition: opacity .2s;
}
.f-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: rgba(30,64,175,.35); }
.f-card:hover::before { opacity: 1; }
.f-icon {
  width: 48px; height: 48px; border-radius: 12px; font-size: 24px;
  display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, var(--brand-soft), #e0f7fb);
  margin-bottom: 16px;
}
.f-card h3 { font-size: 18px; font-weight: 700; margin: 0 0 8px; }
.f-card p { color: var(--text-3); font-size: 14px; margin: 0 0 14px; }
.f-list { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 7px; }
.f-list li { font-size: 13.5px; color: var(--text-2); padding-left: 22px; position: relative; }
.f-list li::before { content: "✓"; position: absolute; left: 0; color: var(--ok); font-weight: 700; }

/* 行业方案 */
.sol-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.sol-card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 24px 22px; box-shadow: var(--shadow); transition: all .2s;
}
.sol-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: rgba(30,64,175,.3); }
.sol-name {
  font-size: 16px; font-weight: 700; margin-bottom: 10px;
  background: linear-gradient(90deg, var(--brand), var(--accent));
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.sol-card p { font-size: 13.5px; color: var(--text-3); margin: 0; }

/* 三步接入 */
.steps { display: flex; align-items: stretch; gap: 8px; margin-bottom: 30px; }
.step {
  flex: 1; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px 24px; box-shadow: var(--shadow); text-align: center;
}
.step-no {
  font-size: 26px; font-weight: 800;
  background: linear-gradient(90deg, var(--brand), var(--accent));
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
  margin-bottom: 10px;
}
.step h3 { font-size: 16px; margin: 0 0 8px; }
.step p { font-size: 13.5px; color: var(--text-3); margin: 0; }
.step-arrow { align-self: center; font-size: 22px; color: var(--muted); flex-shrink: 0; }

.embed-demo { display: flex; gap: 16px; align-items: center; flex-wrap: wrap; }
.embed-code-box {
  flex: 1; min-width: 320px;
  background: #0f172a; border-radius: 12px; padding: 14px 18px;
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  box-shadow: 0 8px 24px rgba(15,23,42,.25);
}
.embed-code-box code { flex: 1; font-size: 12.5px; color: #a5f3fc; font-family: Consolas, monospace; word-break: break-all; }
.embed-lang { font-size: 11px; font-weight: 700; color: #c7d2fe; letter-spacing: 1px; }
.embed-code-box .ghost { background: rgba(255,255,255,.08); border-color: rgba(255,255,255,.2); color: #e2e8f0; }
.embed-code-box .ghost:hover { background: rgba(255,255,255,.16); color: #fff; }
.channel-chips { display: flex; gap: 10px; flex-wrap: wrap; }
.chip {
  font-size: 13px; font-weight: 600; color: var(--brand-dark);
  background: var(--card); border: 1px solid var(--line); border-radius: 20px;
  padding: 8px 18px; box-shadow: var(--shadow);
}

/* 定价 */
.price-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; align-items: start; }
.price-card {
  position: relative; background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 30px 28px; box-shadow: var(--shadow);
  transition: all .2s;
}
.price-card:hover { box-shadow: var(--shadow-lg); }
.price-card.hot {
  border: 2px solid var(--brand);
  box-shadow: var(--shadow-lg);
  transform: scale(1.03);
}
.hot-tag {
  position: absolute; top: -13px; left: 50%; transform: translateX(-50%);
  background: linear-gradient(135deg, var(--brand), var(--accent)); color: #fff;
  font-size: 12px; font-weight: 700; padding: 4px 16px; border-radius: 12px;
  box-shadow: var(--glow); white-space: nowrap;
}
.price-card h3 { font-size: 16px; margin: 0 0 6px; }
.price { font-size: 40px; font-weight: 800; margin: 8px 0 4px; }
.price sup { font-size: 18px; color: var(--text-3); font-weight: 600; margin-right: 2px; }
.price sub { font-size: 15px; color: var(--text-3); font-weight: 400; }
.price-card > .muted { font-size: 13px; margin: 0 0 18px; }
.price-card ul { list-style: none; padding: 0; margin: 0 0 22px; display: flex; flex-direction: column; gap: 9px; }
.price-card li { font-size: 13.5px; color: var(--text-2); padding-left: 22px; position: relative; }
.price-card li::before { content: "✓"; position: absolute; left: 0; color: var(--ok); font-weight: 700; }

/* FAQ */
.faq-list { display: flex; flex-direction: column; gap: 12px; }
.faq {
  background: var(--card); border: 1px solid var(--line); border-radius: 12px;
  overflow: hidden; box-shadow: var(--shadow);
}
.faq-q {
  width: 100%; text-align: left; background: none; border: none;
  font-size: 14.5px; font-weight: 600; color: var(--text);
  padding: 18px 22px; cursor: pointer; display: flex; justify-content: space-between; align-items: center;
}
.faq-q i { font-style: normal; font-size: 20px; color: var(--brand); transition: transform .2s; }
.faq.open .faq-q i { transform: rotate(45deg); }
.faq-a { max-height: 0; overflow: hidden; transition: max-height .3s ease; }
.faq.open .faq-a { max-height: 300px; }
.faq-a p { margin: 0; padding: 0 22px 18px; font-size: 13.5px; color: var(--text-3); line-height: 1.8; }

/* CTA */
.cta { padding-bottom: 90px; }
.cta-card {
  position: relative; text-align: center;
  background: linear-gradient(135deg, #0a1f44, #1e40af 55%, #16567d);
  border-radius: 24px; padding: 56px 40px; color: #fff;
  box-shadow: 0 24px 64px rgba(30,64,175,.35);
  overflow: hidden;
}
.cta-card::before {
  content: ""; position: absolute; inset: 0;
  background-image: linear-gradient(rgba(255,255,255,.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.05) 1px, transparent 1px);
  background-size: 40px 40px; pointer-events: none;
}
.cta-card h2 { position: relative; font-size: 30px; font-weight: 800; margin: 0 0 10px; }
.cta-card > p { position: relative; color: #c7d2fe; margin: 0 0 28px; }
.cta-form {
  position: relative; display: flex; gap: 10px; max-width: 640px; margin: 0 auto; flex-wrap: wrap;
}
.cta-form input {
  flex: 1; min-width: 150px; padding: 13px 16px; border-radius: 11px;
  border: 1px solid rgba(255,255,255,.2); background: rgba(255,255,255,.1);
  color: #fff; font-size: 14px; outline: none; transition: all .15s;
}
.cta-form input::placeholder { color: #a5b4fc; }
.cta-form input:focus { border-color: var(--accent-2); background: rgba(255,255,255,.18); }
.cta-form .btn-primary { position: relative; }
.cta-hint { position: relative; font-size: 12px; color: #a5b4fc; margin: 18px 0 0; }

/* 页脚 */
.footer { background: var(--card); border-top: 1px solid var(--line); padding: 48px 0 20px; }
.footer-inner { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 32px; }
.f-brand p { font-size: 13px; color: var(--text-3); margin: 14px 0 0; line-height: 1.7; }
.f-col h4 { font-size: 13px; font-weight: 700; color: var(--text); margin: 0 0 14px; letter-spacing: .5px; }
.f-col a { display: block; font-size: 13px; color: var(--text-3); text-decoration: none; margin-bottom: 10px; transition: color .15s; }
.f-col a:hover { color: var(--brand); }
.footer-copy { text-align: center; font-size: 12px; color: var(--muted); margin-top: 36px; padding-top: 20px; border-top: 1px solid var(--line); }

/* toast */
.toast {
  position: fixed; bottom: 28px; left: 50%; transform: translateX(-50%);
  background: linear-gradient(135deg, #0a1f44, #1e40af); color: #fff;
  font-size: 13.5px; padding: 12px 24px; border-radius: 11px; z-index: 99;
  box-shadow: 0 10px 32px rgba(30,64,175,.4); border: 1px solid rgba(30,64,175,.4);
  opacity: 0; transition: all .3s;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(-6px); }

/* 滚动进入动画：只在 JS 加 js-enabled 类后才初始隐藏，
   防止 JS 失败/缓存旧版导致整页卡片永久不可见 */
html.js-enabled .reveal { opacity: 0; transform: translateY(24px); transition: all .6s ease; }
html.js-enabled .reveal.in { opacity: 1; transform: none; }

/* ═══ 响应式 ═══ */
@media (max-width: 960px) {
  .hero-inner { grid-template-columns: 1fr; }
  .hero-copy h1 { font-size: 38px; }
  .hero-visual { max-width: 460px; }
  .feature-grid { grid-template-columns: 1fr; }
  .sol-grid { grid-template-columns: repeat(2, 1fr); }
  .steps { flex-direction: column; }
  .step-arrow { transform: rotate(90deg); align-self: center; }
  .price-grid { grid-template-columns: 1fr; }
  .price-card.hot { transform: none; }
  .metrics-inner { grid-template-columns: repeat(2, 1fr); }
  .footer-inner { grid-template-columns: 1fr 1fr; }
  .nav-links { display: none; }
}