/* ============================================================
   AI生图工作台 · 全站样式（全新设计，勿与他站雷同）
   主题色：靛紫渐变 + 玻璃拟态 · 响应式适配手机/电脑端
   ============================================================ */
:root{
  --bg:#f6f5ff;
  --surface:#ffffff;
  --ink:#1c1a2e;
  --ink-soft:#5c5878;
  --brand:#5b3df5;
  --brand-deep:#3a1fb8;
  --brand-2:#9a6bff;
  --accent:#ff7a45;
  --line:#e6e2ff;
  --radius:18px;
  --shadow:0 10px 30px rgba(91,61,245,.12);
  --maxw:1180px;
  --header-h:64px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  font-family:"PingFang SC","Microsoft YaHei","Noto Sans SC","Source Han Sans SC",system-ui,-apple-system,sans-serif;
  background:var(--bg);color:var(--ink);line-height:1.7;font-size:16px;
}
img,svg{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
ul,ol{list-style:none}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 20px}

/* ---------- 顶部导航：下滚隐藏 / 上滚显示 ---------- */
.nav{
  position:fixed;top:0;left:0;right:0;z-index:100;height:var(--header-h);
  background:rgba(255,255,255,.86);backdrop-filter:blur(14px);
  border-bottom:1px solid var(--line);
  transition:transform .28s ease;
}
.nav.nav--hide{transform:translateY(-100%)}
.nav__inner{max-width:var(--maxw);margin:0 auto;padding:0 20px;height:100%;
  display:flex;align-items:center;justify-content:space-between;gap:16px}
.logo{display:flex;align-items:center;gap:10px;font-weight:800;font-size:19px;color:var(--brand-deep);white-space:nowrap}
.logo__mark{width:32px;height:32px;border-radius:9px;flex:0 0 auto;
  background:linear-gradient(135deg,var(--brand),var(--brand-2));
  display:flex;align-items:center;justify-content:center;color:#fff;font-size:15px;font-weight:800}
.nav__links{display:flex;align-items:center;gap:4px}
.nav__links a{padding:8px 12px;border-radius:10px;font-size:14.5px;color:var(--ink-soft);transition:.2s;white-space:nowrap}
.nav__links a:hover{color:var(--brand);background:rgba(91,61,245,.08)}
.nav__links a.is-active{color:var(--brand);font-weight:700;background:rgba(91,61,245,.1)}
.nav__cta{background:linear-gradient(135deg,var(--brand),var(--brand-2));color:#fff !important;
  padding:9px 18px !important;border-radius:12px;font-weight:700;box-shadow:0 6px 16px rgba(91,61,245,.3)}
.nav__cta:hover{filter:brightness(1.08)}
.nav__burger{display:none;width:42px;height:42px;border:1px solid var(--line);border-radius:11px;
  background:#fff;cursor:pointer;position:relative}
.nav__burger span{position:absolute;left:10px;right:10px;height:2px;border-radius:2px;background:var(--ink);
  transition:.25s}
.nav__burger span:nth-child(1){top:13px}
.nav__burger span:nth-child(2){top:20px}
.nav__burger span:nth-child(3){top:27px}
.nav__burger.is-open span:nth-child(1){top:20px;transform:rotate(45deg)}
.nav__burger.is-open span:nth-child(2){opacity:0}
.nav__burger.is-open span:nth-child(3){top:20px;transform:rotate(-45deg)}
.nav__mobile{display:none;position:fixed;top:var(--header-h);left:0;right:0;z-index:99;
  background:#fff;border-bottom:1px solid var(--line);box-shadow:0 18px 30px rgba(28,26,46,.1);
  padding:10px 20px 16px;transform-origin:top;animation:dropIn .22s ease}
@keyframes dropIn{from{opacity:0;transform:translateY(-8px)}to{opacity:1;transform:none}}
.nav__mobile a{display:block;padding:12px 8px;border-bottom:1px dashed var(--line);font-size:15px;color:var(--ink)}
.nav__mobile a.is-active{color:var(--brand);font-weight:700}
.nav__mobile .nav__cta{display:block;text-align:center;margin-top:12px;border-bottom:none}
body.menu-open{overflow:hidden}

/* ---------- Hero ---------- */
.hero{padding:calc(var(--header-h) + 56px) 0 60px;position:relative;overflow:hidden}
.hero::before{content:"";position:absolute;inset:-40% -10% auto;height:130%;z-index:-1;
  background:radial-gradient(600px 300px at 18% 20%,rgba(154,107,255,.18),transparent 60%),
             radial-gradient(520px 280px at 85% 12%,rgba(255,122,69,.14),transparent 60%)}
.hero__grid{display:grid;grid-template-columns:1.05fr .95fr;gap:44px;align-items:center}
.tagline{display:inline-flex;align-items:center;gap:8px;background:rgba(91,61,245,.09);color:var(--brand-deep);
  border:1px solid var(--line);padding:6px 14px;border-radius:999px;font-size:13.5px;font-weight:600;margin-bottom:18px}
.hero h1{font-size:clamp(26px,4vw,42px);line-height:1.32;font-weight:800;letter-spacing:.5px}
.hero h1 em{font-style:normal;background:linear-gradient(120deg,var(--brand),var(--accent));
  -webkit-background-clip:text;background-clip:text;color:transparent}
.hero__desc{margin:16px 0 26px;color:var(--ink-soft);font-size:16.5px;max-width:560px}
.btn-row{display:flex;flex-wrap:wrap;gap:14px}
.btn{display:inline-flex;align-items:center;gap:8px;padding:13px 26px;border-radius:14px;font-weight:700;font-size:15.5px;transition:.2s}
.btn--primary{background:linear-gradient(135deg,var(--brand),var(--brand-2));color:#fff;box-shadow:0 10px 24px rgba(91,61,245,.32)}
.btn--primary:hover{transform:translateY(-2px);filter:brightness(1.06)}
.btn--ghost{border:1.5px solid var(--brand);color:var(--brand);background:#fff}
.btn--ghost:hover{background:rgba(91,61,245,.07)}
.hero__facts{display:flex;gap:26px;margin-top:30px;flex-wrap:wrap}
.hero__facts div strong{display:block;font-size:22px;color:var(--brand-deep);font-weight:800}
.hero__facts div span{font-size:13px;color:var(--ink-soft)}
.hero__art{background:var(--surface);border:1px solid var(--line);border-radius:24px;padding:22px;box-shadow:var(--shadow)}

/* ---------- 通用区块 ---------- */
section.block{padding:64px 0}
.sec-head{text-align:center;max-width:760px;margin:0 auto 42px}
.sec-head h2{font-size:clamp(22px,3vw,30px);font-weight:800;margin-bottom:12px}
.sec-head p{color:var(--ink-soft)}
.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.grid-2{display:grid;grid-template-columns:repeat(2,1fr);gap:22px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:24px;
  box-shadow:0 4px 16px rgba(28,26,46,.05);transition:.25s}
.card:hover{transform:translateY(-4px);box-shadow:var(--shadow)}
.card h3{font-size:18px;margin:14px 0 8px}
.card p{color:var(--ink-soft);font-size:14.5px}
.card .illus{border-radius:12px;overflow:hidden;background:linear-gradient(150deg,#f1eeff,#fdf3ec)}
.steps{counter-reset:step;display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.step{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:24px;position:relative}
.step::before{counter-increment:step;content:"0" counter(step);position:absolute;top:-14px;left:20px;
  width:44px;height:44px;border-radius:12px;background:linear-gradient(135deg,var(--brand),var(--brand-2));
  color:#fff;font-weight:800;display:flex;align-items:center;justify-content:center;font-size:16px}
.step h3{font-size:16.5px;margin:14px 0 6px}
.step p{font-size:14px;color:var(--ink-soft)}

/* FAQ */
.faq{max-width:820px;margin:0 auto}
.faq details{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:18px 22px;margin-bottom:14px}
.faq summary{font-weight:700;cursor:pointer;font-size:15.5px;list-style:none;display:flex;justify-content:space-between;align-items:center}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";color:var(--brand);font-size:20px;font-weight:700}
.faq details[open] summary::after{content:"−"}
.faq details p{margin-top:10px;color:var(--ink-soft);font-size:14.5px}

/* CTA 横幅 */
.cta-band{margin:0 20px;border-radius:26px;padding:56px 30px;text-align:center;color:#fff;
  background:linear-gradient(120deg,var(--brand-deep),var(--brand) 55%,var(--brand-2));box-shadow:var(--shadow)}
.cta-band h2{font-size:clamp(22px,3vw,30px);margin-bottom:12px}
.cta-band p{opacity:.92;margin-bottom:24px}
.cta-band .btn{background:#fff;color:var(--brand-deep)}

/* 页脚 */
.footer{margin-top:70px;border-top:1px solid var(--line);background:#fff}
.footer__inner{max-width:var(--maxw);margin:0 auto;padding:34px 20px;display:flex;flex-wrap:wrap;
  gap:18px;justify-content:space-between;align-items:center}
.footer__links{display:flex;flex-wrap:wrap;gap:6px 18px}
.footer__links a{font-size:14px;color:var(--ink-soft)}
.footer__links a:hover{color:var(--brand)}
.footer__copy{font-size:13px;color:#9a96b5;width:100%}

/* ---------- 响应式 ---------- */
@media (max-width:960px){
  .hero__grid{grid-template-columns:1fr;gap:30px}
  .grid-3{grid-template-columns:repeat(2,1fr)}
  .steps{grid-template-columns:repeat(2,1fr)}
}
@media (max-width:768px){
  .nav__links{display:none}
  .nav__burger{display:block}
  body{font-size:15px}
  section.block{padding:44px 0}
  .hero{padding:calc(var(--header-h) + 34px) 0 40px}
  .grid-3,.grid-2{grid-template-columns:1fr}
  .steps{grid-template-columns:1fr}
  .footer__inner{flex-direction:column;align-items:flex-start}
  .cta-band{margin:0 12px;padding:40px 20px}
}
@media (max-width:420px){
  .hero__facts{gap:16px}
  .hero__facts div strong{font-size:18px}
}