/* Shared styles for Youdao-inspired static site */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei","Segoe UI",Roboto,Helvetica,Arial,sans-serif;color:#222;background:#fff;line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none;transition:color .2s}
a:hover{color:#d8272d}
img{max-width:100%;display:block}
ul{list-style:none}
.container{max-width:1200px;margin:0 auto;padding:0 24px}

/* Header */
.site-header{position:sticky;top:0;z-index:50;background:#fff;border-bottom:1px solid #eee;backdrop-filter:blur(8px)}
.nav{display:flex;align-items:center;justify-content:space-between;height:64px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:20px;color:#d8272d}
.brand img{width:36px;height:36px}
.nav-links{display:flex;gap:32px;align-items:center}
.nav-links a{font-size:15px;font-weight:500;color:#333}
.nav-links a.active{color:#d8272d}
.nav-right{display:flex;align-items:center;gap:16px}
.lang-switch a{font-size:14px;color:#666;padding:4px 8px;border-radius:4px}
.lang-switch a.active{background:#fff5f5;color:#d8272d}
.btn{display:inline-block;padding:10px 22px;border-radius:999px;font-weight:600;font-size:14px;cursor:pointer;transition:all .2s;border:none}
.btn-primary{background:linear-gradient(135deg,#ff5a3c,#d8272d);color:#fff;box-shadow:0 4px 14px rgba(216,39,45,.3)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 6px 20px rgba(216,39,45,.4);color:#fff}
.btn-outline{background:#fff;color:#d8272d;border:1.5px solid #d8272d}
.btn-outline:hover{background:#d8272d;color:#fff}
.btn-lg{padding:14px 32px;font-size:16px}

/* Hero */
.hero{padding:80px 0;background:linear-gradient(135deg,#fff8f6 0%,#ffece8 100%);overflow:hidden}
.hero-grid{display:grid;grid-template-columns:1fr 1fr;gap:60px;align-items:center}
.hero h1{font-size:52px;font-weight:800;line-height:1.15;letter-spacing:-.02em;margin-bottom:20px;color:#1a1a1a}
.hero h1 span{color:#d8272d}
.hero p.lead{font-size:19px;color:#555;margin-bottom:32px;max-width:520px}
.hero-cta{display:flex;gap:14px;flex-wrap:wrap}
.hero-img{border-radius:20px;overflow:hidden;box-shadow:0 20px 60px rgba(216,39,45,.15)}

/* Search bar */
.search-bar{display:flex;background:#fff;border-radius:999px;padding:8px;box-shadow:0 10px 40px rgba(0,0,0,.08);max-width:560px;margin-top:28px}
.search-bar input{flex:1;border:none;outline:none;padding:14px 24px;font-size:16px;background:transparent}
.search-bar button{padding:12px 28px;border-radius:999px;background:#d8272d;color:#fff;border:none;font-weight:600;cursor:pointer}

/* Sections */
.section{padding:80px 0}
.section-alt{background:#fafafa}
.section-title{text-align:center;margin-bottom:56px}
.section-title h2{font-size:38px;font-weight:800;margin-bottom:12px;letter-spacing:-.01em}
.section-title p{color:#666;font-size:17px;max-width:600px;margin:0 auto}

/* Feature grid */
.feature-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.feature-card{background:#fff;border:1px solid #eee;border-radius:16px;padding:32px 24px;transition:all .3s;text-align:left}
.feature-card:hover{transform:translateY(-6px);box-shadow:0 20px 40px rgba(0,0,0,.08);border-color:#ffd6d0}
.feature-icon{width:56px;height:56px;border-radius:14px;background:linear-gradient(135deg,#ff5a3c,#d8272d);display:flex;align-items:center;justify-content:center;color:#fff;font-size:26px;font-weight:700;margin-bottom:20px}
.feature-card h3{font-size:19px;font-weight:700;margin-bottom:10px}
.feature-card p{color:#666;font-size:14.5px}

/* Product row (alternating) */
.product-row{display:grid;grid-template-columns:1fr 1fr;gap:60px;align-items:center;margin-bottom:80px}
.product-row.reverse{direction:rtl}
.product-row.reverse>*{direction:ltr}
.product-row h2{font-size:36px;font-weight:800;margin-bottom:16px;letter-spacing:-.01em}
.product-row .tag{display:inline-block;padding:6px 14px;border-radius:999px;background:#fff5f5;color:#d8272d;font-size:13px;font-weight:600;margin-bottom:16px}
.product-row p{color:#555;font-size:16px;margin-bottom:20px}
.product-row ul.checks{margin-bottom:24px}
.product-row ul.checks li{padding:6px 0 6px 28px;position:relative;color:#333}
.product-row ul.checks li::before{content:"✓";position:absolute;left:0;color:#d8272d;font-weight:800}
.product-row .visual{border-radius:20px;overflow:hidden;box-shadow:0 20px 50px rgba(0,0,0,.1)}

/* Stats */
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;text-align:center}
.stat h3{font-size:44px;font-weight:800;color:#d8272d;letter-spacing:-.02em}
.stat p{color:#666;margin-top:6px}

/* CTA banner */
.cta-banner{background:linear-gradient(135deg,#d8272d 0%,#ff5a3c 100%);color:#fff;padding:64px 32px;border-radius:24px;text-align:center;margin:40px auto}
.cta-banner h2{font-size:34px;font-weight:800;margin-bottom:12px}
.cta-banner p{opacity:.95;margin-bottom:28px;font-size:17px}
.cta-banner .btn{background:#fff;color:#d8272d}
.cta-banner .btn:hover{background:#fff;color:#d8272d;transform:translateY(-2px)}

/* Footer */
.site-footer{background:#1a1a1a;color:#aaa;padding:60px 0 30px;margin-top:40px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:40px;margin-bottom:40px}
.footer-brand{display:flex;align-items:center;gap:10px;color:#fff;font-weight:700;font-size:20px;margin-bottom:14px}
.footer-brand img{width:32px;height:32px}
.footer-col h4{color:#fff;font-size:15px;font-weight:600;margin-bottom:16px}
.footer-col ul li{margin-bottom:10px;font-size:14px}
.footer-col a:hover{color:#fff}
.footer-bottom{border-top:1px solid #333;padding-top:24px;text-align:center;font-size:13px}

/* Sub-page hero */
.subhero{padding:64px 0 40px;background:linear-gradient(135deg,#fff8f6,#ffece8)}
.subhero h1{font-size:44px;font-weight:800;letter-spacing:-.02em;margin-bottom:14px}
.subhero p{font-size:18px;color:#555;max-width:640px}

/* Responsive */
@media (max-width:900px){
  .hero-grid,.product-row,.footer-grid{grid-template-columns:1fr;gap:32px}
  .feature-grid{grid-template-columns:repeat(2,1fr)}
  .stats{grid-template-columns:repeat(2,1fr)}
  .hero h1{font-size:36px}
  .nav-links{display:none}
  .section{padding:56px 0}
  .hero{padding:56px 0}
}