*,:before,:after{box-sizing:border-box;margin:0;padding:0}:root{--brand:#2d5be3;--brand-light:#eef2ff;--brand-dark:#1a3ba8;--surface:#fff;--surface-2:#f8f9fc;--surface-3:#f0f2f8;--border:#00000014;--border-strong:#00000029;--text-1:#0f1117;--text-2:#4a5068;--text-3:#8b92a8;--success:#0e7c50;--success-bg:#edfaf4;--danger:#c0392b;--danger-bg:#fef0ee;--warn-bg:#fff8ec;--warn:#9a6200;--radius:10px;--radius-lg:14px;--shadow:0 1px 3px #00000014, 0 1px 2px #0000000a}body{color:var(--text-1);background:var(--surface-2);-webkit-font-smoothing:antialiased;font-family:Inter,system-ui,-apple-system,sans-serif;font-size:15px;line-height:1.6}button{cursor:pointer;background:0 0;border:none;font-family:inherit}input,select,textarea{font-family:inherit;font-size:inherit}.app{flex-direction:column;min-height:100vh;display:flex}.app-header{background:var(--surface);border-bottom:1px solid var(--border);z-index:10;position:sticky;top:0}.header-inner{justify-content:space-between;align-items:center;max-width:960px;height:56px;margin:0 auto;padding:0 1.5rem;display:flex}.logo{color:inherit;align-items:center;gap:10px;display:flex}.logo-mark{background:var(--brand);color:#fff;border-radius:8px;justify-content:center;align-items:center;width:32px;height:32px;font-size:16px;font-weight:700;display:flex}.logo-text{letter-spacing:-.3px;color:var(--text-1);font-size:16px;font-weight:600}.header-nav{gap:4px;display:flex}.nav-btn{color:var(--text-2);border-radius:6px;padding:6px 14px;font-size:14px;font-weight:500;transition:background .15s,color .15s}.nav-btn:hover{background:var(--surface-3);color:var(--text-1)}.nav-btn.active{background:var(--brand-light);color:var(--brand)}.app-main{flex:1;width:100%;max-width:960px;margin:0 auto;padding:2rem 1.5rem}.page-title{letter-spacing:-.5px;color:var(--text-1);margin-bottom:.25rem;font-size:24px;font-weight:700}.page-subtitle{color:var(--text-3);margin-bottom:2rem;font-size:14px}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);box-shadow:var(--shadow);padding:1.5rem}.card-title{color:var(--text-2);text-transform:uppercase;letter-spacing:.5px;margin-bottom:1rem;font-size:14px;font-weight:600}.btn{border-radius:var(--radius);cursor:pointer;align-items:center;gap:6px;padding:9px 18px;font-size:14px;font-weight:500;transition:all .15s;display:inline-flex}.btn-primary{background:var(--brand);color:#fff;border:1px solid #0000}.btn-primary:hover{background:var(--brand-dark)}.btn-primary:disabled{opacity:.45;cursor:not-allowed}.btn-secondary{background:var(--surface);color:var(--text-1);border:1px solid var(--border-strong)}.btn-secondary:hover{background:var(--surface-3)}.btn-ghost{color:var(--text-2);background:0 0;border:1px solid #0000;padding:6px 10px}.btn-ghost:hover{background:var(--surface-3);color:var(--text-1)}.btn-danger{background:var(--danger-bg);color:var(--danger);border:1px solid #0000}.btn-danger:hover{background:#fde0dc}.form-label{color:var(--text-2);margin-bottom:6px;font-size:13px;font-weight:500;display:block}.form-input{border:1px solid var(--border-strong);border-radius:var(--radius);width:100%;color:var(--text-1);background:var(--surface);outline:none;padding:8px 12px;font-size:14px;transition:border-color .15s}.form-input:focus{border-color:var(--brand);box-shadow:0 0 0 3px #2d5be31a}.form-select{border:1px solid var(--border-strong);border-radius:var(--radius);width:100%;color:var(--text-1);background:var(--surface);appearance:none;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%238B92A8' stroke-width='2'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");background-position:right 12px center;background-repeat:no-repeat;outline:none;padding:8px 36px 8px 12px;font-size:14px;transition:border-color .15s}.form-select:focus{border-color:var(--brand);box-shadow:0 0 0 3px #2d5be31a}.badge{border-radius:20px;align-items:center;padding:2px 8px;font-size:12px;font-weight:500;display:inline-flex}.badge-blue{background:var(--brand-light);color:var(--brand)}.badge-green{background:var(--success-bg);color:var(--success)}.badge-warn{background:var(--warn-bg);color:var(--warn)}.badge-danger{background:var(--danger-bg);color:var(--danger)}.difficulty-1{color:#1b6b1b;background:#edf7ed}.difficulty-2{color:#0b5fa5;background:#e8f4fd}.difficulty-3{color:#856404;background:#fff3cd}.difficulty-4{color:#9b1c1c;background:#fde8e8}.difficulty-5{color:#6b21a8;background:#f3e8ff}.error-banner{background:var(--danger-bg);border-radius:var(--radius);color:var(--danger);border:1px solid #fcc;margin-bottom:1rem;padding:12px 16px;font-size:14px}.spinner{border:2px solid #ffffff4d;border-top-color:#fff;border-radius:50%;width:20px;height:20px;animation:.7s linear infinite spin;display:inline-block}.spinner-dark{border-color:#2d5be333;border-top-color:var(--brand)}@keyframes spin{to{transform:rotate(360deg)}}.empty-state{text-align:center;color:var(--text-3);padding:3rem 1rem}.empty-state-icon{opacity:.4;margin-bottom:1rem;font-size:40px}.empty-state h3{color:var(--text-2);margin-bottom:.5rem;font-size:16px;font-weight:600}.empty-state p{font-size:14px}@media (width<=600px){.app-main{padding:1rem}.header-inner{padding:0 1rem}}