/* ============================================================
   ChangelessSaaS — 平台官网设计系统 platform.css
   v2026-08-30 · 暗色科技风（与现有 accent 令牌一致）
   配套：app/home/HomeLayout.php
   ============================================================ */

:root{
  --bg:#0F0F1A;
  --bg-2:#14142A;
  --bg-3:#1A1A2E;
  --surface:rgba(255,255,255,.04);
  --surface-2:rgba(255,255,255,.065);
  --border:rgba(255,255,255,.08);
  --border-strong:rgba(255,255,255,.16);
  --text:#ECECF1;
  --text-dim:#B6B6C8;
  --muted:#8B8B9E;
  --accent:#6C63FF;
  --accent-2:#00D2FF;
  --accent-grad:linear-gradient(135deg,#6C63FF 0%,#00D2FF 100%);
  --success:#10B981;
  --warn:#F59E0B;
  --danger:#EF4444;
  --radius:16px;
  --radius-sm:10px;
  --shadow:0 18px 50px rgba(0,0,0,.45);
  --shadow-sm:0 8px 24px rgba(0,0,0,.35);
  --maxw:1180px;
  --ease:cubic-bezier(.22,.61,.36,1);
}

/* ---------- reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;font-family:system-ui,-apple-system,"Segoe UI",Roboto,"PingFang SC","Microsoft YaHei",sans-serif;
  background:var(--bg);color:var(--text);line-height:1.65;overflow-x:hidden;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
button{font-family:inherit}
h1,h2,h3,h4{margin:0;font-weight:700;line-height:1.25;letter-spacing:-.01em}
p{margin:0}
ul{margin:0;padding:0;list-style:none}

/* ---------- a11y ---------- */
:focus-visible{outline:2px solid var(--accent-2);outline-offset:3px;border-radius:4px}
.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}

/* ---------- layout ---------- */
.container{width:100%;max-width:var(--maxw);margin:0 auto;padding:0 24px}
.section{padding:96px 0}
.section--tight{padding:64px 0}
.section__head{max-width:760px;margin:0 auto 56px;text-align:center}
.section__title{font-size:clamp(26px,3.4vw,38px);margin-bottom:14px}
.section__title .grad{background:var(--accent-grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.section__subtitle{color:var(--text-dim);font-size:clamp(15px,1.6vw,17px)}

/* ---------- buttons ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:12px 26px;border-radius:var(--radius-sm);font-size:15px;font-weight:600;
  border:1px solid transparent;cursor:pointer;transition:transform .2s var(--ease),box-shadow .2s var(--ease),background .2s,border-color .2s;white-space:nowrap}
.btn--primary{background:var(--accent-grad);color:#fff;box-shadow:0 10px 30px rgba(108,99,255,.35)}
.btn--primary:hover{transform:translateY(-2px);box-shadow:0 16px 40px rgba(108,99,255,.5)}
.btn--ghost{background:var(--surface);border-color:var(--border);color:var(--text)}
.btn--ghost:hover{border-color:var(--accent);background:rgba(108,99,255,.1)}
.btn--light{background:#fff;color:#14142A}
.btn--light:hover{transform:translateY(-2px);box-shadow:0 12px 30px rgba(255,255,255,.18)}
.btn--lg{padding:15px 34px;font-size:16px}
.btn--block{width:100%}

/* ---------- header ---------- */
.site-header{position:sticky;top:0;z-index:200;background:rgba(15,15,26,.82);
  backdrop-filter:blur(18px);-webkit-backdrop-filter:blur(18px);border-bottom:1px solid var(--border)}
.site-header__inner{max-width:var(--maxw);margin:0 auto;display:flex;align-items:center;justify-content:space-between;padding:14px 24px}
.brand{display:flex;align-items:center;gap:10px;font-size:19px;font-weight:800;color:var(--text)}
.brand__mark{width:30px;height:30px;border-radius:8px;background:var(--accent-grad);
  display:grid;place-items:center;color:#fff;font-size:15px;font-weight:900;box-shadow:0 4px 14px rgba(108,99,255,.4)}
.brand span{background:var(--accent-grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.nav{display:flex;align-items:center;gap:4px}
.nav a{color:var(--text-dim);padding:8px 14px;border-radius:8px;font-size:14.5px;font-weight:500;transition:color .2s,background .2s}
.nav a:hover{color:var(--text);background:var(--surface)}
.nav a.active{color:#fff;background:rgba(108,99,255,.14)}
.nav__cta{margin-left:8px}
.nav-toggle{display:none;width:42px;height:42px;border:1px solid var(--border);border-radius:10px;
  background:var(--surface);cursor:pointer;position:relative}
.nav-toggle span,.nav-toggle span::before,.nav-toggle span::after{content:'';position:absolute;left:11px;width:20px;height:2px;background:var(--text);border-radius:2px;transition:.25s var(--ease)}
.nav-toggle span{top:20px}
.nav-toggle span::before{top:-6px}
.nav-toggle span::after{top:6px}
.nav-toggle.open span{background:transparent}
.nav-toggle.open span::before{top:0;transform:rotate(45deg)}
.nav-toggle.open span::after{top:0;transform:rotate(-45deg)}
.nav-mobile{display:none;flex-direction:column;gap:4px;padding:12px 16px 20px;border-bottom:1px solid var(--border);background:var(--bg-2)}
.nav-mobile a{padding:12px 14px;border-radius:10px;color:var(--text-dim);font-weight:500}
.nav-mobile a.active{color:#fff;background:rgba(108,99,255,.14)}
.nav-mobile .btn{margin-top:8px}

/* ---------- hero ---------- */
.hero{position:relative;text-align:center;padding:110px 24px 90px;overflow:hidden}
.hero__glow{position:absolute;inset:0;pointer-events:none;z-index:0}
.hero__glow::before{content:'';position:absolute;top:-260px;left:50%;transform:translateX(-50%);
  width:760px;height:760px;background:radial-gradient(circle,rgba(108,99,255,.16),transparent 62%)}
.hero__glow::after{content:'';position:absolute;bottom:-220px;right:-120px;width:480px;height:480px;
  background:radial-gradient(circle,rgba(0,210,255,.1),transparent 62%)}
.hero__inner{position:relative;z-index:1;max-width:880px;margin:0 auto}
.hero__badge{display:inline-flex;align-items:center;gap:8px;padding:7px 16px;border-radius:999px;
  background:var(--surface-2);border:1px solid var(--border);color:var(--text-dim);font-size:13px;margin-bottom:26px}
.hero__badge .dot{width:7px;height:7px;border-radius:50%;background:var(--success);box-shadow:0 0 10px var(--success)}
.hero h1{font-size:clamp(32px,5.4vw,56px);line-height:1.12;margin-bottom:22px}
.hero h1 .grad{background:var(--accent-grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero__sub{font-size:clamp(15px,2vw,19px);color:var(--text-dim);max-width:660px;margin:0 auto 38px;line-height:1.7}
.hero__cta{display:flex;gap:14px;justify-content:center;flex-wrap:wrap}
.hero__note{margin-top:20px;font-size:13px;color:var(--muted)}

/* ---------- stats ---------- */
.stats{border-top:1px solid var(--border);border-bottom:1px solid var(--border);background:var(--bg-2)}
.stats__grid{max-width:var(--maxw);margin:0 auto;display:grid;grid-template-columns:repeat(4,1fr)}
.stat{padding:40px 24px;text-align:center;border-right:1px solid var(--border)}
.stat:last-child{border-right:none}
.stat__num{font-size:clamp(30px,4vw,44px);font-weight:800;background:var(--accent-grad);
  -webkit-background-clip:text;background-clip:text;color:transparent}
.stat__label{font-size:13px;color:var(--muted);margin-top:6px;letter-spacing:.4px}

/* ---------- grids / cards ---------- */
.grid{display:grid;gap:22px}
.grid--2{grid-template-columns:repeat(2,1fr)}
.grid--3{grid-template-columns:repeat(3,1fr)}
.grid--4{grid-template-columns:repeat(4,1fr)}
.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:28px;
  transition:transform .25s var(--ease),border-color .25s,box-shadow .25s}
.card:hover{transform:translateY(-5px);border-color:var(--border-strong);box-shadow:var(--shadow-sm)}
.card__icon{width:52px;height:52px;border-radius:14px;display:grid;place-items:center;font-size:26px;
  background:rgba(108,99,255,.12);border:1px solid rgba(108,99,255,.25);margin-bottom:18px}
.card__title{font-size:18px;margin-bottom:10px}
.card__desc{color:var(--text-dim);font-size:14.5px;line-height:1.7}

/* ---------- templates ---------- */
.tpl-card{position:relative;overflow:hidden;display:flex;flex-direction:column}
.tpl-card::before{content:'';position:absolute;top:0;left:0;right:0;height:3px;background:var(--accent-grad);opacity:0;transition:opacity .25s}
.tpl-card:hover::before{opacity:1}
.tpl-card__icon{font-size:34px;margin-bottom:12px}
.tpl-card__title{font-size:17px;font-weight:600;margin-bottom:6px}
.tpl-card__desc{font-size:13.5px;color:var(--text-dim);line-height:1.6;flex:1}
.tpl-card__link{display:inline-block;margin-top:14px;font-size:13.5px;font-weight:600;color:var(--accent-2)}

/* ---------- pricing ---------- */
.pricing{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;align-items:stretch}
.plan{position:relative;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:30px 26px;display:flex;flex-direction:column;transition:transform .25s var(--ease),border-color .25s,box-shadow .25s}
.plan:hover{transform:translateY(-5px);box-shadow:var(--shadow-sm)}
.plan--featured{border-color:rgba(108,99,255,.5);background:linear-gradient(180deg,rgba(108,99,255,.1),var(--surface));box-shadow:0 20px 50px rgba(108,99,255,.2)}
.plan__ribbon{position:absolute;top:16px;right:-34px;transform:rotate(45deg);background:var(--accent-grad);
  color:#fff;font-size:11px;font-weight:700;padding:5px 40px;letter-spacing:.5px}
.plan__name{font-size:17px;font-weight:700;margin-bottom:6px}
.plan__tagline{font-size:13px;color:var(--muted);min-height:38px;margin-bottom:16px}
.plan__price{font-size:34px;font-weight:800;line-height:1.1;margin-bottom:4px}
.plan__price .cur{font-size:20px;vertical-align:super;margin-right:2px}
.plan__billing{font-size:13px;color:var(--text-dim);margin-bottom:20px}
.plan__points{display:flex;flex-direction:column;gap:11px;margin-bottom:26px;flex:1}
.plan__points li{display:flex;gap:9px;font-size:14px;color:var(--text-dim);align-items:flex-start}
.plan__points li::before{content:'✓';color:var(--success);font-weight:800;flex-shrink:0}
.plan .btn{margin-top:auto}

/* ---------- cases ---------- */
.cases{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.case{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:28px;
  transition:transform .25s var(--ease),border-color .25s}
.case:hover{transform:translateY(-5px);border-color:var(--border-strong)}
.case__logo{width:48px;height:48px;border-radius:12px;background:var(--accent-grad);display:grid;place-items:center;
  color:#fff;font-weight:800;font-size:18px;margin-bottom:16px}
.case__title{font-size:17px;margin-bottom:8px}
.case__desc{font-size:14px;color:var(--text-dim);line-height:1.7;margin-bottom:14px}
.case__tag{display:inline-block;font-size:12px;color:var(--accent-2);background:rgba(0,210,255,.1);
  border:1px solid rgba(0,210,255,.22);padding:3px 10px;border-radius:999px}

/* ---------- FAQ ---------- */
.faq{max-width:820px;margin:0 auto;display:flex;flex-direction:column;gap:12px}
.faq__item{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-sm);overflow:hidden}
.faq__item summary{list-style:none;cursor:pointer;padding:18px 22px;font-size:16px;font-weight:600;
  display:flex;justify-content:space-between;align-items:center;gap:14px}
.faq__item summary::-webkit-details-marker{display:none}
.faq__item summary::after{content:'+';font-size:22px;color:var(--muted);transition:transform .2s var(--ease);flex-shrink:0}
.faq__item[open] summary::after{transform:rotate(45deg);color:var(--accent-2)}
.faq__body{padding:0 22px 20px;color:var(--text-dim);font-size:14.5px;line-height:1.8}

/* ---------- CTA band ---------- */
.cta-band{position:relative;overflow:hidden;border-radius:24px;margin:0 auto;max-width:var(--maxw);
  padding:64px 40px;text-align:center;background:linear-gradient(135deg,rgba(108,99,255,.16),rgba(0,210,255,.12));
  border:1px solid var(--border-strong)}
.cta-band::before{content:'';position:absolute;width:400px;height:400px;border-radius:50%;
  background:radial-gradient(circle,rgba(108,99,255,.25),transparent 60%);top:-160px;left:-100px;pointer-events:none}
.cta-band h2{font-size:clamp(24px,3vw,34px);margin-bottom:12px;position:relative}
.cta-band p{color:var(--text-dim);margin-bottom:28px;position:relative}
.cta-band .hero__cta{position:relative}

/* ---------- footer ---------- */
.site-footer{border-top:1px solid var(--border);background:var(--bg-2);margin-top:0}
.site-footer__grid{max-width:var(--maxw);margin:0 auto;padding:56px 24px 32px;display:grid;
  grid-template-columns:1.6fr 1fr 1fr 1fr;gap:32px}
.site-footer__brand .brand{margin-bottom:14px}
.site-footer__brand p{color:var(--muted);font-size:13.5px;line-height:1.7;max-width:280px}
.site-footer__col h4{font-size:14px;color:var(--text);margin-bottom:14px}
.site-footer__col a{display:block;color:var(--muted);font-size:13.5px;padding:5px 0;transition:color .2s}
.site-footer__col a:hover{color:var(--accent-2)}
.site-footer__bottom{border-top:1px solid var(--border);padding:20px 24px;max-width:var(--maxw);margin:0 auto;
  display:flex;justify-content:space-between;align-items:center;gap:16px;flex-wrap:wrap;
  font-size:12.5px;color:var(--muted)}
.site-footer__bottom a{color:var(--muted)}
.site-footer__bottom a:hover{color:var(--accent-2)}
.beian{display:inline-flex;align-items:center;gap:4px}
.beian img{width:14px;height:14px;vertical-align:-2px;border:0}

/* ---------- reveal animation ---------- */
.reveal{opacity:0;transform:translateY(24px);transition:opacity .7s var(--ease),transform .7s var(--ease)}
.reveal.is-visible{opacity:1;transform:none}

/* ---------- misc ---------- */
.eyebrow{display:inline-block;font-size:13px;font-weight:600;letter-spacing:.6px;color:var(--accent-2);
  text-transform:uppercase;margin-bottom:14px}
.lead{font-size:16px;color:var(--text-dim);max-width:680px}
.center{text-align:center}
.mt-s{margin-top:24px}.mt-m{margin-top:40px}.mt-l{margin-top:64px}
.divider{height:1px;background:var(--border);border:0;margin:0}

/* ============ responsive ============ */
@media (max-width:980px){
  .nav{display:none}
  .nav-toggle{display:block}
  .nav-mobile.show{display:flex}
  .grid--4,.grid--3,.pricing{grid-template-columns:repeat(2,1fr)}
  .cases{grid-template-columns:repeat(2,1fr)}
  .stats__grid{grid-template-columns:repeat(2,1fr)}
  .stat:nth-child(2n){border-right:none}
  .stat:nth-child(-n+2){border-bottom:1px solid var(--border)}
  .site-footer__grid{grid-template-columns:1fr 1fr}
}
@media (max-width:620px){
  .section{padding:64px 0}
  .hero{padding:72px 18px 56px}
  .grid--4,.grid--3,.grid--2,.pricing,.cases{grid-template-columns:1fr}
  .stats__grid{grid-template-columns:1fr}
  .stat{border-right:none;border-bottom:1px solid var(--border)}
  .stat:last-child{border-bottom:none}
  .site-footer__grid{grid-template-columns:1fr;gap:24px}
  .hero__cta .btn,.cta-band .hero__cta .btn{width:100%}
  .container{padding:0 18px}
}
@media (prefers-reduced-motion:reduce){
  *{animation-duration:.001ms!important;transition-duration:.001ms!important;scroll-behavior:auto!important}
  .reveal{opacity:1;transform:none}
}

/* ============ pricing compare table ============ */
.cmp{overflow-x:auto;margin-top:28px;border:1px solid var(--border);border-radius:var(--radius);background:var(--surface)}
.cmp table{width:100%;border-collapse:collapse;min-width:720px}
.cmp th,.cmp td{padding:14px 16px;text-align:center;font-size:14px;border-bottom:1px solid var(--border)}
.cmp th:first-child,.cmp td:first-child{text-align:left;color:var(--text-dim);position:sticky;left:0;background:var(--bg-2);font-weight:500}
.cmp thead th{background:var(--bg-3);font-weight:700;color:var(--text)}
.cmp thead th.feat{background:rgba(108,99,255,.16);color:#fff}
.cmp tbody tr:hover{background:var(--surface-2)}
.cmp .yes{color:var(--success);font-weight:700}
.cmp .no{color:var(--muted)}
.cmp .v{color:var(--text)}

/* ============ feature detail blocks ============ */
.feat-block{display:grid;grid-template-columns:1fr 1fr;gap:44px;align-items:center;padding:52px 0;border-bottom:1px solid var(--border)}
.feat-block:last-child{border-bottom:none}
.feat-block:nth-child(even) .feat-block__media{order:2}
.feat-block__media{height:248px;border-radius:var(--radius);background:linear-gradient(135deg,rgba(108,99,255,.18),rgba(0,210,255,.12));border:1px solid var(--border);display:grid;place-items:center;font-size:64px}
.feat-block h3{font-size:23px;margin-bottom:12px}
.feat-block p{color:var(--text-dim);margin-bottom:16px}
.feat-block ul{display:flex;flex-direction:column;gap:10px}
.feat-block li{display:flex;gap:9px;color:var(--text-dim);font-size:14.5px}
.feat-block li::before{content:'✓';color:var(--success);font-weight:800}

/* ============ about ============ */
.about-hero{text-align:center;padding:96px 24px 36px}
.about-hero h1{font-size:clamp(28px,4vw,46px);margin-bottom:16px}
.about-hero h1 .grad{background:var(--accent-grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.about-hero p{color:var(--text-dim);max-width:700px;margin:0 auto;font-size:16px}
.values{display:grid;grid-template-columns:repeat(3,1fr);gap:22px;margin-top:44px}
.value{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:28px}
.value__icon{font-size:30px;margin-bottom:12px}
.value h3{font-size:17px;margin-bottom:8px}
.value p{color:var(--text-dim);font-size:14px;line-height:1.7}

/* ============ contact ============ */
.contact-wrap{display:grid;grid-template-columns:1fr 1fr;gap:52px;align-items:start}
.contact-info h3{font-size:18px;margin:20px 0 6px}
.contact-info p{color:var(--text-dim);font-size:14.5px;line-height:1.7}
.contact-form{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:30px}
.field{margin-bottom:16px}
.field label{display:block;font-size:13px;color:var(--text-dim);margin-bottom:6px}
.field input,.field textarea{width:100%;padding:11px 13px;border:1px solid var(--border);border-radius:var(--radius-sm);background:var(--bg);color:var(--text);font-size:14.5px;font-family:inherit}
.field input:focus,.field textarea:focus{outline:none;border-color:var(--accent)}
.field textarea{resize:vertical;min-height:120px}
.form-msg{background:rgba(16,185,129,.12);border:1px solid rgba(16,185,129,.3);color:var(--success);padding:12px 14px;border-radius:var(--radius-sm);margin-bottom:16px;font-size:14px}
.form-err{background:rgba(239,68,68,.12);border:1px solid rgba(239,68,68,.3);color:var(--danger);padding:12px 14px;border-radius:var(--radius-sm);margin-bottom:16px;font-size:14px}

/* ============ policy prose ============ */
.prose{max-width:840px;margin:0 auto}
.prose h2{font-size:22px;margin:38px 0 12px}
.prose h3{font-size:17px;margin:24px 0 8px;color:var(--text)}
.prose p{color:var(--text-dim);margin-bottom:14px;line-height:1.85;font-size:15px}
.prose ul{margin:0 0 14px 20px;color:var(--text-dim);line-height:1.85;font-size:15px}
.prose li{margin-bottom:6px}

@media (max-width:820px){
  .feat-block,.contact-wrap{grid-template-columns:1fr;gap:24px}
  .feat-block:nth-child(even) .feat-block__media{order:0}
  .values{grid-template-columns:1fr}
}