:root{--primary:#1677ff;--primary-dark:#0f5fd1;--bg:#f5f7fb;--card:#fff;--text:#1f2329;--sub:#6b7280;--border:#e5e7eb;--success:#16a34a;--warning:#f59e0b;--danger:#ef4444;--shadow:0 8px 24px #0f172a14;--radius:16px}*{box-sizing:border-box}body{max-width:750px;color:var(--text);background:linear-gradient(#eaf2ff 0%,#f5f7fb 18% 100%);margin:0 auto;font-family:-apple-system,BlinkMacSystemFont,PingFang SC,Microsoft YaHei,sans-serif}.app{background:var(--bg);position:relative}