*,:before,:after{box-sizing:border-box;margin:0;padding:0}:root{--bg-page:#f5f7fb;--bg-card:#fff;--bg-soft:#f8fafc;--bg-muted:#f1f5f9;--border-card:#e2e8f0;--border-soft:#eef2f7;--border-strong:#cbd5e1;--text-primary:#1f2937;--text-secondary:#4b5563;--text-muted:#64748b;--text-faint:#94a3b8;--color-primary:#2563eb;--color-primary-hover:#1d4ed8;--color-primary-soft:#eff6ff;--radius-card:10px;--radius-control:8px;--radius-pill:999px;--shadow-card:0 -1px 0 #0f172a0a, 0 1px 2px #0000000a;--shadow-flat:0 1px 2px #0000000a;--space-page:1.5rem;--page-frame-padding-y:1rem;--page-frame-padding-x:20px;--page-frame-padding-bottom:1.25rem;--page-section-gap:.8rem;--page-section-gap-mobile:1rem;--space-toolbar:.6rem 1rem;--header-height:40px;--font-family:system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;--font-size-base:15px;--font-size-sm:13px;--font-size-lg:16px;--font-size-title:15px;--font-size-toolbar:14px;--font-weight-title:600;font-family:var(--font-family);font-size:var(--font-size-base);color:var(--text-primary);background-color:var(--bg-page);font-synthesis:none;text-rendering:optimizelegibility;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;font-weight:400;line-height:1.5}html,body,#app{width:100%;height:100%;overflow:hidden}a{color:inherit;cursor:pointer;text-decoration:none}img,svg{max-width:100%;height:auto}::-webkit-scrollbar{width:6px;height:6px}::-webkit-scrollbar-track{background:0 0}::-webkit-scrollbar-thumb{background:#cbd5e1;border-radius:3px}::-webkit-scrollbar-thumb:hover{background:#94a3b8}.page-stack{gap:var(--page-section-gap);flex-direction:column;min-width:0;display:flex}.page-fill{flex:1;min-height:0}.page-card{background:var(--bg-card);border:1px solid var(--border-card);border-radius:var(--radius-card);box-shadow:var(--shadow-card)}.page-toolbar{padding:var(--space-toolbar);background:var(--bg-card);border:1px solid var(--border-card);border-radius:var(--radius-card);box-shadow:var(--shadow-card);font-size:var(--font-size-toolbar);flex-wrap:wrap;align-items:center;gap:.75rem;display:flex}.page-pagination{justify-content:flex-end;padding:.5rem 0;display:flex}.btn{border-radius:var(--radius-control);height:36px;font-size:var(--font-size-base);cursor:pointer;white-space:nowrap;-webkit-user-select:none;user-select:none;border:1px solid #0000;justify-content:center;align-items:center;gap:6px;padding:0 14px;font-weight:500;line-height:1;transition:all .15s;display:inline-flex}.btn:disabled{opacity:.5;cursor:not-allowed}.btn-primary{background:var(--color-primary);border-color:var(--color-primary);color:#fff}.btn-primary:hover:not(:disabled){background:var(--color-primary-hover);border-color:var(--color-primary-hover)}.btn-secondary{color:var(--text-secondary);background:#fff;border-color:#d9e2ef}.btn-secondary:hover:not(:disabled){color:var(--color-primary);background:#f8fbff;border-color:#93c5fd}.btn-danger{color:#dc2626;background:#fff;border-color:#fecaca}.btn-danger:hover:not(:disabled){background:#fef2f2;border-color:#fca5a5}.btn-ghost{color:var(--color-primary);background:0 0;border-color:#0000;padding:0 8px}.btn-ghost:hover:not(:disabled){background:var(--color-primary-soft)}.btn-sm{height:30px;font-size:var(--font-size-sm);padding:0 10px}.badge{border-radius:var(--radius-pill);white-space:nowrap;align-items:center;padding:4px 12px;font-size:13px;font-weight:600;line-height:1.4;display:inline-flex}.badge-grade{color:#2177a6;background:#eaf7ff}.badge-period{color:#168096;background:#e9fbff}.badge-subject{color:#19906c;background:#e9f9f2}.badge-difficulty{color:#a57113;background:#fff4d8}.badge-type{color:#7c3faf;background:#f2e9ff}.section-header{height:var(--header-height);border-bottom:1px solid var(--border-soft);font-size:var(--font-size-title);font-weight:var(--font-weight-title);color:var(--text-primary);background:0 0;align-items:center;padding:0 1rem;display:flex}