:root{--bg: #f6f7fb;--surface: #ffffff;--text: #1f2430;--text-dim: #6b7280;--primary: #4f46e5;--primary-soft: #eef2ff;--border: #e6e8ef;--shadow: 0 1px 3px rgba(20, 24, 40, .06), 0 8px 24px rgba(20, 24, 40, .06);--radius: 14px}*{box-sizing:border-box}html,body{margin:0;padding:0;background:var(--bg);color:var(--text);font-family:system-ui,-apple-system,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif;line-height:1.6;-webkit-font-smoothing:antialiased}a{color:var(--primary);text-decoration:none}.wrap{max-width:1040px;margin:0 auto;padding:0 20px}.site-header{background:var(--surface);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:20}.site-header .wrap{display:flex;align-items:center;justify-content:space-between;gap:12px;height:62px}.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:18px}.brand .logo{width:30px;height:30px;border-radius:9px;background:linear-gradient(135deg,#6366f1,#22d3ee);display:grid;place-items:center;color:#fff;font-size:16px}.brand small{display:block;font-weight:400;font-size:12px;color:var(--text-dim)}.nav-back{font-size:14px;color:var(--text-dim)}.grid-tip{font-size:13px;color:var(--text-dim)}button{font-family:inherit;font-size:14px;font-weight:600;cursor:pointer;border:none;border-radius:10px;padding:10px 16px;background:var(--primary);color:#fff;transition:opacity .15s}button:hover{opacity:.9}button.ghost{background:var(--primary-soft);color:var(--primary)}button:disabled{opacity:.5;cursor:not-allowed}footer.site-footer{text-align:center;color:var(--text-dim);font-size:12.5px;padding:24px 0 40px}.lang-switch{font-family:inherit;font-size:13px;color:var(--text-dim);padding:5px 8px;border-radius:8px;border:1px solid var(--border);background:var(--surface);cursor:pointer}.lang-switch:hover{opacity:.85}