/* ============================================================
   YHDDWD 产品展示站 — 样式
   无外部依赖（不加载任何 CDN / 字体 / 图标库），纯静态可直接部署
   ============================================================ */

:root{
  --brand:#0b5fff;
  --brand-dark:#0843b8;
  --accent:#00b8a9;
  --ink:#0f172a;
  --body:#41506b;
  --muted:#78879d;
  --line:#e3e9f2;
  --bg:#ffffff;
  --bg-alt:#f5f8fd;
  --radius:14px;
  --shadow:0 10px 30px rgba(15,23,42,.07);
  --shadow-lg:0 20px 50px rgba(15,23,42,.12);
  --wrap:1140px;
}

*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:system-ui,-apple-system,"Segoe UI",Roboto,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  color:var(--body);
  background:var(--bg);
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
h1,h2,h3,h4{color:var(--ink);line-height:1.25;margin:0 0 .6em;font-weight:700}
h1{font-size:clamp(1.9rem,4vw,3rem);letter-spacing:-.02em}
h2{font-size:clamp(1.5rem,2.6vw,2.1rem);letter-spacing:-.01em}
h3{font-size:1.15rem}
p{margin:0 0 1em}
ul{margin:0;padding:0;list-style:none}

/* ---------- 语言切换：中文 .zh / 英文 .en ---------- */
html[data-lang="zh"] .en{display:none!important}
html[data-lang="en"] .zh{display:none!important}

/* ---------- 布局 ---------- */
.wrap{max-width:var(--wrap);margin:0 auto;padding:0 22px}
.section{padding:88px 0}
.section.alt{background:var(--bg-alt)}
.section-head{max-width:720px;margin:0 auto 52px;text-align:center}
.section-head p{color:var(--muted);margin:0}
.eyebrow{
  display:inline-block;font-size:.78rem;font-weight:700;letter-spacing:.14em;
  text-transform:uppercase;color:var(--brand);margin-bottom:14px;
}
.grid{display:grid;gap:22px}
.g2{grid-template-columns:repeat(auto-fit,minmax(320px,1fr))}
.g3{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}
.g4{grid-template-columns:repeat(auto-fit,minmax(230px,1fr))}

/* ---------- 顶部导航 ---------- */
.site-header{
  position:sticky;top:0;z-index:50;background:rgba(255,255,255,.9);
  backdrop-filter:blur(10px);border-bottom:1px solid var(--line);
}
.header-inner{display:flex;align-items:center;gap:18px;height:68px}
.logo{display:flex;align-items:center;gap:10px;font-weight:800;color:var(--ink);font-size:1.12rem;letter-spacing:-.01em;flex:none}
.logo-mark{
  width:30px;height:30px;border-radius:9px;flex:none;
  background:linear-gradient(135deg,var(--brand),var(--accent));
  display:grid;place-items:center;color:#fff;font-size:.82rem;font-weight:800;
}
.nav{display:flex;gap:4px;margin-left:auto;flex-wrap:wrap}
.nav a{
  padding:8px 12px;border-radius:9px;font-size:.93rem;font-weight:500;
  color:var(--body);transition:.18s;
}
.nav a:hover{background:var(--bg-alt);color:var(--brand)}
.header-actions{display:flex;align-items:center;gap:10px;flex:none}
.lang-switch{display:flex;border:1px solid var(--line);border-radius:9px;overflow:hidden;background:#fff}
.lang-switch button{
  border:0;background:transparent;padding:7px 11px;cursor:pointer;
  font:inherit;font-size:.84rem;font-weight:600;color:var(--muted);transition:.18s;
}
.lang-switch button.active{background:var(--brand);color:#fff}
.nav-toggle{display:none;border:1px solid var(--line);background:#fff;border-radius:9px;padding:8px 10px;cursor:pointer;font:inherit}

/* ---------- 按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:13px 24px;border-radius:11px;font-weight:600;font-size:.95rem;
  border:1px solid transparent;cursor:pointer;transition:.2s;font-family:inherit;
}
.btn-primary{background:var(--brand);color:#fff;box-shadow:0 6px 18px rgba(11,95,255,.25)}
.btn-primary:hover{background:var(--brand-dark);transform:translateY(-1px)}
.btn-ghost{background:#fff;color:var(--ink);border-color:var(--line)}
.btn-ghost:hover{border-color:var(--brand);color:var(--brand)}
.btn-sm{padding:9px 16px;font-size:.88rem;border-radius:9px}

/* ---------- 首屏 ---------- */
.hero{padding:78px 0 70px;background:
  radial-gradient(900px 420px at 12% -10%,rgba(11,95,255,.09),transparent 60%),
  radial-gradient(700px 380px at 92% 0%,rgba(0,184,169,.10),transparent 60%);
}
.hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:52px;align-items:center}
.hero h1{margin-bottom:18px}
.hero-lead{font-size:1.08rem;max-width:33em}
.hero-cta{display:flex;gap:12px;flex-wrap:wrap;margin:26px 0 30px}
.hero-facts{display:flex;gap:30px;flex-wrap:wrap;border-top:1px solid var(--line);padding-top:22px}
.fact strong{display:block;color:var(--ink);font-size:1.02rem}
.fact span{font-size:.85rem;color:var(--muted)}

/* ---------- 占位图（部署前替换为实拍图） ---------- */
.ph{
  position:relative;border-radius:var(--radius);overflow:hidden;
  background:
    linear-gradient(135deg,rgba(11,95,255,.10),rgba(0,184,169,.12)),
    repeating-linear-gradient(45deg,#eef3fb 0 12px,#e7eef9 12px 24px);
  border:1px solid var(--line);
  display:grid;place-items:center;text-align:center;color:var(--muted);
  font-size:.85rem;font-weight:600;letter-spacing:.02em;
}
.ph::after{content:"";position:absolute;inset:0;box-shadow:inset 0 0 0 1px rgba(255,255,255,.5)}
.ph-hero{aspect-ratio:4/3;box-shadow:var(--shadow-lg)}
.ph-card{aspect-ratio:16/10}
.ph-wide{aspect-ratio:21/9}

/* ---------- 卡片 ---------- */
.card{
  background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  padding:26px;transition:.22s;
}
.card:hover{box-shadow:var(--shadow);transform:translateY(-3px);border-color:#d3ddec}
.card h3{margin-bottom:8px}
.card p{font-size:.94rem;margin:0}
.icon{
  width:44px;height:44px;border-radius:12px;display:grid;place-items:center;
  background:rgba(11,95,255,.08);color:var(--brand);margin-bottom:16px;
}
.icon svg{width:22px;height:22px;stroke:currentColor;fill:none;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}

/* ---------- 产品卡 ---------- */
.product-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;transition:.22s;display:flex;flex-direction:column}
.product-card:hover{box-shadow:var(--shadow);transform:translateY(-3px)}
.product-body{padding:22px;flex:1;display:flex;flex-direction:column}
.product-body ul{margin:12px 0 18px;font-size:.9rem}
.product-body li{padding-left:20px;position:relative;color:var(--body);margin-bottom:6px}
.product-body li::before{content:"";position:absolute;left:4px;top:.62em;width:6px;height:6px;border-radius:50%;background:var(--accent)}
.product-body .btn{margin-top:auto;align-self:flex-start}
.tag{
  display:inline-block;font-size:.74rem;font-weight:700;letter-spacing:.06em;
  color:var(--brand);background:rgba(11,95,255,.08);
  padding:3px 9px;border-radius:999px;margin-bottom:10px;text-transform:uppercase;
}

/* ---------- 表格 ---------- */
.table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:var(--radius);background:#fff}
table{width:100%;border-collapse:collapse;font-size:.92rem;min-width:560px}
th,td{padding:14px 18px;text-align:left;border-bottom:1px solid var(--line)}
th{background:var(--bg-alt);color:var(--ink);font-weight:600}
tbody tr:last-child td{border-bottom:0}
tbody tr:hover{background:#fafcff}

/* ---------- 场景 ---------- */
.scene{padding:24px;border-radius:var(--radius);background:#fff;border:1px solid var(--line)}
.scene h4{margin:0 0 6px;color:var(--ink);font-size:1rem}
.scene p{margin:0;font-size:.9rem;color:var(--muted)}

/* ---------- FAQ ---------- */
.faq{max-width:820px;margin:0 auto}
.faq details{background:#fff;border:1px solid var(--line);border-radius:12px;padding:0 20px;margin-bottom:12px}
.faq summary{
  cursor:pointer;font-weight:600;color:var(--ink);padding:18px 0;
  list-style:none;display:flex;justify-content:space-between;align-items:center;gap:16px;
}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-size:1.3rem;color:var(--brand);font-weight:400;line-height:1}
.faq details[open] summary::after{content:"–"}
.faq details p{padding-bottom:6px;margin:0 0 14px;font-size:.94rem}

/* ---------- CTA 区块 ---------- */
.cta{
  background:linear-gradient(135deg,#0f172a,#123a7a 60%,#0b5fff);
  color:#fff;border-radius:18px;padding:52px 44px;text-align:center;
}
.cta h2{color:#fff}
.cta p{color:rgba(255,255,255,.8);max-width:44em;margin:0 auto 26px}
.cta .btn-primary{background:#fff;color:var(--brand);box-shadow:none}
.cta .btn-primary:hover{background:#eef4ff}
.cta .btn-ghost{background:transparent;color:#fff;border-color:rgba(255,255,255,.35)}
.cta .btn-ghost:hover{background:rgba(255,255,255,.1);color:#fff}
.cta-actions{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}

/* ---------- 联系页 ---------- */
.contact-grid{display:grid;grid-template-columns:1fr 1fr;gap:44px;align-items:start}
.info-item{display:flex;gap:14px;padding:18px 0;border-bottom:1px solid var(--line)}
.info-item:last-child{border-bottom:0}
.info-item .icon{margin:0;flex:none}
.info-item h4{margin:0 0 4px;font-size:.98rem}
.info-item p{margin:0;font-size:.92rem;color:var(--muted)}
.form-row{margin-bottom:16px}
label{display:block;font-size:.88rem;font-weight:600;color:var(--ink);margin-bottom:6px}
input,textarea,select{
  width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:10px;
  font:inherit;font-size:.94rem;color:var(--ink);background:#fff;transition:.18s;
}
input:focus,textarea:focus,select:focus{outline:0;border-color:var(--brand);box-shadow:0 0 0 3px rgba(11,95,255,.12)}
textarea{min-height:120px;resize:vertical}
.form-note{font-size:.84rem;color:var(--muted);margin-top:12px}

/* ---------- 页脚 ---------- */
.site-footer{background:#0f172a;color:rgba(255,255,255,.62);padding:56px 0 28px;font-size:.9rem}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:36px;margin-bottom:34px}
.site-footer h4{color:#fff;font-size:.95rem;margin-bottom:14px}
.site-footer a:hover{color:#fff}
.site-footer li{margin-bottom:9px}
.footer-bottom{border-top:1px solid rgba(255,255,255,.12);padding-top:22px;display:flex;justify-content:space-between;gap:14px;flex-wrap:wrap;font-size:.84rem}
.logo-inverse{color:#fff}

/* ---------- 页头（内页） ---------- */
.page-head{padding:64px 0 44px;background:var(--bg-alt);border-bottom:1px solid var(--line)}
.page-head p{color:var(--muted);max-width:46em;margin:0}
.crumb{font-size:.85rem;color:var(--muted);margin-bottom:14px}
.crumb a:hover{color:var(--brand)}

/* ---------- 出场动画 ---------- */
.reveal{opacity:0;transform:translateY(16px);transition:opacity .6s ease,transform .6s ease}
.reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){.reveal{opacity:1;transform:none;transition:none}}

/* ---------- 响应式 ---------- */
@media (max-width:900px){
  .hero-grid{grid-template-columns:1fr;gap:36px}
  .contact-grid{grid-template-columns:1fr;gap:30px}
  .footer-grid{grid-template-columns:1fr 1fr}
  .section{padding:64px 0}
}
@media (max-width:720px){
  .nav{
    display:none;position:absolute;top:68px;left:0;right:0;background:#fff;
    border-bottom:1px solid var(--line);flex-direction:column;padding:12px 18px;gap:2px;
  }
  .nav.open{display:flex}
  .nav a{padding:12px}
  .nav-toggle{display:block}
  .header-inner{position:relative}
  .header-actions .btn{display:none}
  .cta{padding:40px 24px}
  .footer-grid{grid-template-columns:1fr}
  .hero-facts{gap:20px}
}