:root{color-scheme:light dark;--bg:#f5f6f8;--surface:#fff;--border:#e2e4e9;--text:#1a1d23;--text-muted:#6b7280;--accent:#5b8def;--danger:#e5484d}@media (prefers-color-scheme:dark){:root{--bg:#0f1115;--surface:#171a21;--border:#2a2e37;--text:#eceef1;--text-muted:#9aa1ac}}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif}a{color:inherit}.page{max-width:960px;margin:0 auto;padding:32px 20px 64px}.header{display:flex;align-items:center;justify-content:space-between;margin-bottom:28px}.header h1{font-size:1.4rem;margin:0}.button{background:var(--accent);color:#fff;border:none;border-radius:8px;padding:10px 16px;font-size:.9rem;cursor:pointer}.button:disabled{opacity:.6;cursor:default}.button.secondary{background:transparent;color:var(--text-muted);border:1px solid var(--border)}.card-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));grid-gap:16px;gap:16px}.card{display:block;background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:20px;text-decoration:none;transition:transform .1s ease,border-color .1s ease}.card:hover{transform:translateY(-2px);border-color:var(--accent)}.card-dot{width:10px;height:10px;border-radius:50%;margin-bottom:12px}.card h2{font-size:1.05rem;margin:0 0 6px}.card p{margin:0;line-height:1.4}.back-link,.card p{font-size:.85rem;color:var(--text-muted)}.back-link{text-decoration:none;margin-bottom:16px;display:inline-block}.lesson-list{display:flex;flex-direction:column;gap:10px;margin-top:20px}.lesson-row{display:flex;align-items:center;justify-content:space-between;background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:14px 16px}.lesson-when{font-weight:600;font-size:.95rem}.lesson-when small{display:block;font-weight:400;color:var(--text-muted);font-size:.78rem}.lesson-teacher{text-align:right}.lesson-teacher .name{font-weight:600}.lesson-teacher .label{display:block;font-size:.75rem;color:var(--text-muted)}.empty-state{color:var(--text-muted);font-size:.9rem;padding:24px 0}.error-banner{background:rgba(229,72,77,.12);border:1px solid var(--danger);color:var(--danger);padding:10px 14px;border-radius:8px;font-size:.85rem;margin-bottom:16px}.login-wrap{min-height:100vh;display:flex;align-items:center;justify-content:center}.login-card{background:var(--surface);border:1px solid var(--border);border-radius:14px;padding:32px;width:320px}.login-card h1{font-size:1.2rem;margin:0 0 20px}.field{margin-bottom:14px}.field label{display:block;font-size:.8rem;color:var(--text-muted);margin-bottom:6px}.field input{width:100%;padding:10px 12px;border-radius:8px;border:1px solid var(--border);background:var(--bg);color:var(--text);font-size:.9rem}.toolbar{display:flex;gap:10px;align-items:center;margin:20px 0}.sync-result{font-size:.85rem;color:var(--text-muted)}.stats-bar{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));grid-gap:16px;gap:16px;background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:18px 20px;margin-bottom:24px}.stat-item{display:flex;flex-direction:column;gap:6px}.stat-label{font-size:.72rem;color:var(--text-muted);text-transform:uppercase;letter-spacing:.04em}.stat-value{font-size:1rem;font-weight:600}.stat-bar-track{height:4px;background:var(--border);border-radius:2px;overflow:hidden}.stat-bar-fill{height:100%;background:var(--accent);border-radius:2px}.stats-unavailable{font-size:.85rem;color:var(--text-muted);margin-bottom:24px}