:root{--bg:#f3f5f9;--surface:#fff;--surface-soft:#f7f8fc;--primary:#2563eb;--primary-soft:#dbeafe;--text:#1f2937;--text-muted:#6b7280;--border:#e5e7eb;--danger:#ef4444;--radius-sm:0px;--radius-md:0px;--radius-lg:0px;--shadow-sm:0 1px 2px #00000014;--shadow-md:0 8px 24px #0f172a14}*{box-sizing:border-box}html,body,#root{width:100%;min-height:100vh;margin:0}body{color:var(--text);background:var(--bg);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Hiragino Sans GB,Microsoft YaHei,sans-serif}a{color:inherit;text-decoration:none}button,input{font:inherit}.app-shell{background:var(--surface-soft);width:min(100%,750px);min-height:100vh;margin:0 auto;position:relative}.page-body{padding:0 12px 84px}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);box-shadow:var(--shadow-sm)}.section-title{margin:0;font-size:14px;font-weight:600}.muted{color:var(--text-muted)}.page-placeholder{text-align:center;border:1px dashed var(--border);border-radius:var(--radius-md);background:var(--surface);margin-top:12px;padding:24px 16px}.grid{gap:10px;display:grid}.grid-4{grid-template-columns:repeat(4,minmax(0,1fr))}@media (width<=420px){.grid-4{grid-template-columns:repeat(3,minmax(0,1fr))}}