/* === 爱思助手 全局公共样式 shared.css === */
*{margin:0;padding:0;box-sizing:border-box}
:root{
  --bg-primary:#0a0e17;
  --bg-secondary:#111827;
  --bg-card:#1a1f2e;
  --bg-card-hover:#1f2537;
  --accent-blue:#007AFF;
  --accent-purple:#A048ED;
  --accent-gradient:linear-gradient(135deg,#A048ED,#007AFF);
  --text-primary:#e8eaed;
  --text-secondary:#9aa0b0;
  --text-muted:#6b7280;
  --border-color:rgba(255,255,255,0.06);
  --shadow:0 4px 24px rgba(0,0,0,0.4);
}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;background:var(--bg-primary);color:var(--text-primary);line-height:1.7;min-height:100vh}
a{color:var(--accent-blue);text-decoration:none;transition:color .2s}
a:hover{color:#3395ff}
img{max-width:100%;height:auto}
.container{max-width:1200px;margin:0 auto;padding:0 24px}

/* === Header === */
.site-header{background:rgba(10,14,23,0.92);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-bottom:1px solid var(--border-color);position:sticky;top:0;z-index:100}
.header-inner{display:flex;align-items:center;justify-content:space-between;height:64px;max-width:1200px;margin:0 auto;padding:0 24px}
.logo-area{display:flex;align-items:center;gap:12px}
.logo-area img{width:40px;height:40px;border-radius:8px}
.logo-text{font-size:18px;font-weight:700;background:var(--accent-gradient);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.main-nav{display:flex;align-items:center;gap:4px;list-style:none}
.main-nav a{display:block;padding:8px 18px;border-radius:8px;color:var(--text-secondary);font-size:15px;font-weight:500;transition:all .2s}
.main-nav a:hover,.main-nav a.active{color:#fff;background:rgba(0,122,255,0.12)}
.main-nav a.download-btn{background:var(--accent-gradient);color:#fff;font-weight:600;padding:8px 22px;border-radius:20px}
.main-nav a.download-btn:hover{opacity:.9;background:var(--accent-gradient)}

/* === Footer === */
.site-footer{background:var(--bg-secondary);border-top:1px solid var(--border-color);padding:48px 0 24px;margin-top:64px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:40px;margin-bottom:40px}
.footer-col h5{font-size:15px;font-weight:700;margin-bottom:16px}
.footer-col p,.footer-col a{font-size:14px;color:var(--text-muted);line-height:2.2;display:block}
.footer-col a:hover{color:var(--accent-blue)}
.footer-bottom{text-align:center;padding-top:24px;border-top:1px solid var(--border-color);font-size:13px;color:var(--text-muted)}

/* === 键盘可访问性 === */
a:focus-visible,
button:focus-visible,
.btn-primary:focus-visible,
.btn-outline:focus-visible,
.card-link:focus-visible,
.dl-btn:focus-visible,
.main-nav a:focus-visible,
.tab-btn:focus-visible,
.page-num:focus-visible{
  outline:2px solid var(--accent-blue);
  outline-offset:2px;
  border-radius:4px;
}

/* === 全局响应式 === */
@media(max-width:768px){
  .main-nav{display:none}
  .header-inner{justify-content:space-between}
  .footer-grid{grid-template-columns:1fr}
}