/* 听潮 TideSignal 官网 —— 与客户端同一套视觉语言（珊瑚→品红→紫） */
:root{
  --brand:#FF4D4D; --brand-2:#FF8A5B; --brand-ink:#DE3232; --brand-soft:#FFEDEC;
  --violet:#7C5CFF; --teal:#0FB5A5; --amber:#FFB020;
  --grad:linear-gradient(135deg,#FF8A5B 0%,#FF3D4E 100%);
  --grad-hero:linear-gradient(125deg,#FF7A4D 0%,#FF3D6E 48%,#7C5CFF 100%);
  --ink:#171A26; --ink-2:#5A6072; --ink-3:#9AA0B4;
  --line:#EBEBF2; --bg:#FFFFFF; --bg-alt:#F7F7FB; --dark:#0E1017;
  --r:18px; --r-lg:26px;
  --maxw:1120px;
  --ease:cubic-bezier(.2,.8,.2,1);
  --font:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei","Segoe UI",system-ui,sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{font-family:var(--font);color:var(--ink);background:var(--bg);line-height:1.6;
  -webkit-font-smoothing:antialiased;overflow-x:hidden}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}

/* 导航 */
.nav{position:sticky;top:0;z-index:100;background:rgba(255,255,255,.72);backdrop-filter:saturate(180%) blur(20px);
  -webkit-backdrop-filter:saturate(180%) blur(20px);border-bottom:1px solid transparent;transition:border-color .3s,background .3s}
.nav.stuck{border-bottom-color:var(--line)}
.nav-in{max-width:var(--maxw);margin:0 auto;padding:0 24px;height:56px;display:flex;align-items:center;gap:28px}
.brand{display:flex;align-items:center;gap:9px;font-weight:700;font-size:16px;letter-spacing:.02em}
.links{display:flex;gap:26px;margin-left:auto;font-size:13.5px;color:var(--ink-2)}
.links a{transition:color .2s}
.links a:hover{color:var(--ink)}

/* 按钮 */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;height:46px;padding:0 26px;
  border-radius:999px;font-size:15px;font-weight:600;transition:transform .2s var(--ease),box-shadow .2s,filter .2s;white-space:nowrap}
.btn-sm{height:34px;padding:0 16px;font-size:13px}
.btn-primary{background:var(--grad);color:#fff;box-shadow:0 6px 20px rgba(255,61,78,.28)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 12px 28px rgba(255,61,78,.36)}
.btn-ghost{background:#fff;color:var(--ink);border:1px solid var(--line)}
.btn-ghost:hover{border-color:var(--ink-3);transform:translateY(-2px)}
.btn-ghost.light{background:rgba(255,255,255,.12);color:#fff;border-color:rgba(255,255,255,.3)}
.btn-block{width:100%}

/* Hero */
.hero{max-width:var(--maxw);margin:0 auto;padding:88px 24px 0;text-align:center}
.eyebrow{font-size:13px;font-weight:700;letter-spacing:.18em;text-transform:uppercase;color:var(--brand-ink);margin-bottom:18px}
.h1{font-size:clamp(38px,6.4vw,72px);line-height:1.08;font-weight:700;letter-spacing:-.025em}
.h2{font-size:clamp(28px,4.2vw,46px);line-height:1.18;font-weight:700;letter-spacing:-.02em;margin-bottom:14px}
.h3{font-size:19px;font-weight:700}
.grad-text{background:var(--grad-hero);-webkit-background-clip:text;background-clip:text;color:transparent}
.lede{margin:22px auto 0;max-width:660px;font-size:clamp(16px,1.7vw,19px);color:var(--ink-2);line-height:1.75}
.cta-row{margin-top:34px;display:flex;gap:14px;justify-content:center;flex-wrap:wrap}
.cta-row.center{margin-top:30px}
.fine{margin-top:22px;font-size:12.5px;color:var(--ink-3)}
.fine.center{text-align:center;margin-top:26px}

/* 产品截图 */
.shot{margin:64px auto 0;max-width:1180px;padding:0 24px;perspective:1600px}
.shot-frame{border-radius:16px;overflow:hidden;border:1px solid var(--line);
  box-shadow:0 40px 90px rgba(23,26,38,.22),0 4px 14px rgba(23,26,38,.08);background:#fff}
.shot-frame img{display:block;width:100%}
.shot-2{margin-top:56px}

/* 数字条 */
.strip{margin-top:88px;background:var(--bg-alt);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.strip-in{max-width:var(--maxw);margin:0 auto;padding:44px 24px;display:grid;grid-template-columns:repeat(4,1fr);gap:24px;text-align:center}
.stat b{display:block;font-size:clamp(30px,4vw,44px);font-weight:700;letter-spacing:-.02em;
  background:var(--grad-hero);-webkit-background-clip:text;background-clip:text;color:transparent;font-variant-numeric:tabular-nums}
.stat span{display:block;margin-top:6px;font-size:13px;color:var(--ink-3)}

/* 通用区块 */
.sec{max-width:var(--maxw);margin:0 auto;padding:104px 24px}
.sec.alt{max-width:none;background:var(--bg-alt);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.sec.alt>*{max-width:var(--maxw);margin-left:auto;margin-right:auto}
.kicker{font-size:12.5px;font-weight:700;letter-spacing:.16em;text-transform:uppercase;color:var(--brand-ink);margin-bottom:12px}
.sub{font-size:17px;color:var(--ink-2);max-width:640px;margin-bottom:44px}

/* 功能卡片 */
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:44px}
.card{padding:30px 28px;border:1px solid var(--line);border-radius:var(--r-lg);background:#fff;
  transition:transform .3s var(--ease),box-shadow .3s,border-color .3s}
.card:hover{transform:translateY(-6px);box-shadow:0 22px 50px rgba(23,26,38,.1);border-color:#E3E3EE}
.card .ic{width:44px;height:44px;border-radius:13px;background:var(--brand-soft);display:flex;align-items:center;justify-content:center;margin-bottom:18px}
.card .ic img{width:22px;height:22px}
.card h3{font-size:17px;font-weight:700;margin-bottom:8px}
.card p{font-size:14.5px;color:var(--ink-2);line-height:1.75}

/* 深色流程区 */
.sec.dark{max-width:none;background:var(--dark);color:#fff;padding:104px 24px}
.sec.dark>.kicker{color:var(--brand-2)}
.sec.dark>.h2,.sec.dark .steps{max-width:var(--maxw);margin-left:auto;margin-right:auto}
.sec.dark .step p{color:rgba(255,255,255,.66)}
.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:28px;margin-top:48px}
.step .sn{display:inline-flex;width:38px;height:38px;border-radius:12px;background:var(--grad-hero);
  color:#fff;font-weight:700;align-items:center;justify-content:center;margin-bottom:14px;font-size:15px}
.step h3{font-size:17px;font-weight:700;margin-bottom:8px}
.step p{font-size:14.5px;color:var(--ink-2);line-height:1.75}

/* 价格 */
.price-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;align-items:stretch}
.plan{position:relative;padding:34px 28px;border:1px solid var(--line);border-radius:var(--r-lg);background:#fff;display:flex;flex-direction:column}
.plan.best{border-color:transparent;background:linear-gradient(#fff,#fff) padding-box,var(--grad-hero) border-box;border:1.5px solid transparent;
  box-shadow:0 24px 60px rgba(255,61,110,.16);transform:translateY(-8px)}
.plan .tag{position:absolute;top:-12px;left:50%;transform:translateX(-50%);background:var(--grad-hero);color:#fff;
  font-size:11.5px;font-weight:700;padding:4px 14px;border-radius:999px;white-space:nowrap}
.plan h3{font-size:16px;font-weight:700}
.p-price{font-size:40px;font-weight:700;letter-spacing:-.03em;margin:12px 0 2px;font-variant-numeric:tabular-nums}
.p-price b{font-weight:700}
.p-price span{font-size:14px;font-weight:500;color:var(--ink-3);margin-left:4px}
.p-note{font-size:13px;color:var(--ink-3);margin-bottom:22px}
.plan ul{list-style:none;margin-bottom:26px;flex:1}
.plan li{font-size:14px;color:var(--ink-2);padding:7px 0 7px 24px;position:relative;line-height:1.6}
.plan li::before{content:"";position:absolute;left:0;top:14px;width:14px;height:14px;border-radius:50%;
  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='%23DE3232' stroke-width='3.4' stroke-linecap='round'%3E%3Cpath d='M20 6 9 17l-5-5'/%3E%3C/svg%3E") center/9px no-repeat}

/* 下载 */
.dl-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin:44px auto 0}
.dl{padding:26px 22px;border:1px solid var(--line);border-radius:var(--r-lg);background:#fff;
  display:flex;flex-direction:column;gap:6px;transition:transform .25s var(--ease),box-shadow .25s,border-color .25s}
.dl:hover{transform:translateY(-5px);box-shadow:0 18px 40px rgba(23,26,38,.1);border-color:var(--brand)}
.dl-os{font-size:11.5px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--ink-3)}
.dl b{font-size:17px;font-weight:700}
.dl-fmt{font-size:12.5px;color:var(--ink-3)}
.dl-tip{position:absolute;top:14px;right:14px;font-size:11px;font-weight:700;color:var(--ink-3);
  background:var(--bg-alt);border:1px solid var(--line);padding:2px 9px;border-radius:999px}
.ul{text-decoration:underline;text-underline-offset:2px;color:var(--brand-ink);font-weight:600;cursor:pointer}
.req{display:grid;grid-template-columns:repeat(3,1fr);gap:26px;margin:44px auto 0;text-align:left}
.req b{display:block;font-size:14px;margin-bottom:6px}
.req p{font-size:13.5px;color:var(--ink-2);line-height:1.7}

/* FAQ */
.faq{margin-top:40px;border-top:1px solid var(--line)}
.faq details{border-bottom:1px solid var(--line);padding:4px 0}
.faq summary{cursor:pointer;list-style:none;padding:22px 40px 22px 0;font-size:16.5px;font-weight:600;position:relative}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"";position:absolute;right:6px;top:50%;width:11px;height:11px;
  border-right:2px solid var(--ink-3);border-bottom:2px solid var(--ink-3);transform:translateY(-70%) rotate(45deg);transition:transform .25s}
.faq details[open] summary::after{transform:translateY(-25%) rotate(-135deg)}
.faq details p{padding:0 0 22px;font-size:14.5px;color:var(--ink-2);line-height:1.85;max-width:760px}

/* 结尾 CTA */
.cta-band{background:var(--grad-hero);color:#fff;text-align:center;padding:96px 24px}
.cta-band .h2{color:#fff}
.cta-band .btn-ghost{background:rgba(255,255,255,.14);border-color:rgba(255,255,255,.32);color:#fff}

/* 页脚 */
.foot{background:var(--dark);color:rgba(255,255,255,.62);padding:44px 24px}
.foot-in{max-width:var(--maxw);margin:0 auto;display:flex;align-items:center;gap:24px;flex-wrap:wrap}
.fbrand{display:flex;align-items:center;gap:9px;color:#fff;font-weight:700;font-size:14px}
.fcopy{font-size:12.5px;line-height:1.7;flex:1;min-width:280px}
.flinks{display:flex;gap:20px;font-size:13px}
.flinks a:hover{color:#fff}

/* 入场动画 */
.rv{opacity:0;transform:translateY(24px);transition:opacity .7s var(--ease),transform .7s var(--ease)}
.rv.in{opacity:1;transform:none}

@media (max-width:960px){
  .links{display:none}
  .grid,.steps,.price-grid,.dl-grid,.req,.strip-in{grid-template-columns:1fr}
  .strip-in{grid-template-columns:repeat(2,1fr)}
  .grid,.steps{grid-template-columns:repeat(2,1fr)}
  .plan.best{transform:none}
  .sec,.sec.dark{padding:72px 22px}
  .hero{padding-top:56px}
}
@media (max-width:640px){
  .grid,.steps,.dl-grid,.req{grid-template-columns:1fr}
  .strip-in{grid-template-columns:1fr 1fr;gap:28px}
}