@charset "UTF-8";:root{--primary: #4f7fff;--primary-light: #eef2ff;--primary-dark: #3a65e8;--success: #22c55e;--success-light: #f0fdf4;--danger: #ef4444;--danger-light: #fef2f2;--gray-50: #f9fafb;--gray-100: #f3f4f6;--gray-200: #e5e7eb;--gray-300: #d1d5db;--gray-400: #9ca3af;--gray-500: #6b7280;--gray-600: #4b5563;--gray-700: #374151;--gray-800: #1f2937;--gray-900: #111827;--border-radius: 8px;--border-radius-sm: 4px;--font-sans: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif}*,*:before,*:after{box-sizing:border-box}html,body{margin:0;padding:0;font-family:var(--font-sans);font-size:16px;color:var(--gray-800);background:#fff}h1,h2,h3,h4,h5{margin:0 0 .5rem;line-height:1.25}p{margin:0 0 .75rem}a{color:var(--primary)}input,select,textarea{font-family:inherit;font-size:.9rem;padding:.45rem .65rem;border:1px solid var(--gray-300);border-radius:var(--border-radius-sm);outline:none;transition:border-color .15s,box-shadow .15s;background:#fff;color:var(--gray-800)}input:focus,select:focus,textarea:focus{border-color:var(--primary);box-shadow:0 0 0 3px #4f7fff26}textarea{resize:vertical}button{font-family:inherit;font-size:.875rem;font-weight:500;cursor:pointer;border:none;border-radius:var(--border-radius-sm);padding:.45rem .9rem;transition:background .15s,opacity .15s}button:disabled{opacity:.55;cursor:not-allowed}.btn-primary{background:var(--primary);color:#fff}.btn-primary:hover:not(:disabled){background:var(--primary-dark)}.btn-secondary{background:#fff;color:var(--primary);border:1px solid var(--primary)}.btn-secondary:hover:not(:disabled){background:var(--primary-light)}.btn-ghost{background:transparent;color:var(--gray-600)}.btn-ghost:hover:not(:disabled){background:var(--gray-100)}.btn-danger{background:var(--danger);color:#fff}.btn-danger:hover:not(:disabled){background:#dc2626}.btn-sm{font-size:.8rem;padding:.25rem .6rem}.alert-error{background:var(--danger-light);color:var(--danger);border:1px solid #fecaca;border-radius:var(--border-radius-sm);padding:.6rem .85rem;font-size:.875rem;margin-bottom:1rem}.badge{display:inline-block;padding:.15rem .45rem;border-radius:999px;font-size:.75rem;font-weight:600}.diff-easy{background:#d1fae5;color:#065f46}.diff-medium{background:#fef3c7;color:#92400e}.diff-hard{background:#fee2e2;color:#991b1b}.page{padding:1.5rem;max-width:1100px}@media(max-width:600px){.page{padding:1rem}}.page-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:1.25rem}.page-header h2{margin:0}.loading{color:var(--gray-400);font-size:.9rem}.empty{color:var(--gray-400)}