*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;background:#f0f2f5;min-height:100vh;display:flex;align-items:flex-start;justify-content:center;padding:40px 16px;color:#1a1a2e}.container{background:#fff;border-radius:16px;box-shadow:0 4px 24px #00000014;padding:32px;width:100%;max-width:520px}header{margin-bottom:28px}h1{font-size:2rem;font-weight:700;color:#1a1a2e;letter-spacing:-.5px}.subtitle{margin-top:4px;font-size:.9rem;color:#6b7280}.add-form{display:flex;gap:8px;margin-bottom:24px}.todo-input{flex:1;padding:10px 14px;border:2px solid #e5e7eb;border-radius:10px;font-size:.95rem;outline:none;transition:border-color .2s;background:#f9fafb}.todo-input:focus{border-color:#6366f1;background:#fff}.add-btn{padding:10px 20px;background:#6366f1;color:#fff;border:none;border-radius:10px;font-size:.95rem;font-weight:600;cursor:pointer;transition:background .2s,opacity .2s}.add-btn:hover:not(:disabled){background:#4f46e5}.add-btn:disabled{opacity:.4;cursor:not-allowed}.error{display:flex;align-items:center;justify-content:space-between;background:#fef2f2;border:1px solid #fecaca;color:#dc2626;padding:10px 14px;border-radius:10px;margin-bottom:16px;font-size:.875rem;gap:12px}.error button{background:none;border:none;color:#dc2626;cursor:pointer;font-size:.8rem;text-decoration:underline;white-space:nowrap}.loading{text-align:center;color:#9ca3af;padding:32px 0;font-size:.95rem}.todo-list{list-style:none;display:flex;flex-direction:column;gap:8px}.empty{text-align:center;color:#9ca3af;padding:32px 0;font-size:.95rem}.todo-item{display:flex;align-items:center;gap:12px;padding:12px 14px;border-radius:10px;border:1px solid #e5e7eb;background:#fff;transition:background .15s,border-color .15s}.todo-item:hover{background:#f9fafb;border-color:#d1d5db}.todo-item.completed .todo-text{text-decoration:line-through;color:#9ca3af}.checkbox{width:22px;height:22px;border-radius:6px;border:2px solid #d1d5db;background:#fff;cursor:pointer;flex-shrink:0;display:flex;align-items:center;justify-content:center;font-size:.75rem;font-weight:700;color:#fff;transition:background .15s,border-color .15s}.todo-item.completed .checkbox{background:#6366f1;border-color:#6366f1}.checkbox:hover{border-color:#6366f1}.todo-text{flex:1;font-size:.95rem;line-height:1.4;word-break:break-word}.delete-btn{background:none;border:none;color:#d1d5db;font-size:1.3rem;line-height:1;cursor:pointer;flex-shrink:0;padding:2px 4px;border-radius:4px;transition:color .15s,background .15s}.delete-btn:hover{color:#ef4444;background:#fef2f2}