.app{background:#fff;border-radius:12px;box-shadow:0 4px 24px #00000014;padding:2rem;width:100%;max-width:480px}h1{font-size:1.8rem;color:#1a1a2e;margin-bottom:1.5rem;text-align:center}.error{color:#e74c3c;margin-bottom:1rem;font-size:.9rem;text-align:center}.add-form{display:flex;gap:.5rem;margin-bottom:1.5rem}.add-form input{flex:1;padding:.6rem .9rem;border:1px solid #ddd;border-radius:8px;font-size:1rem;outline:none;transition:border-color .2s}.add-form input:focus{border-color:#6c63ff}.add-form button{padding:.6rem 1.2rem;background:#6c63ff;color:#fff;border:none;border-radius:8px;font-size:1rem;cursor:pointer;transition:background .2s}.add-form button:hover{background:#574fd6}.todo-list{list-style:none;display:flex;flex-direction:column;gap:.5rem}.todo-list .empty{text-align:center;color:#aaa;padding:1.5rem 0}.todo-list li{display:flex;align-items:center;justify-content:space-between;padding:.7rem 1rem;border:1px solid #eee;border-radius:8px;background:#fafafa;transition:background .15s}.todo-list li:hover{background:#f3f0ff}.todo-list li span{cursor:pointer;flex:1;font-size:1rem;color:#333;-webkit-user-select:none;user-select:none}.todo-list li.completed span{text-decoration:line-through;color:#aaa}.delete-btn{background:none;border:none;color:#ccc;font-size:1rem;cursor:pointer;padding:0 .25rem;transition:color .2s}.delete-btn:hover{color:#e74c3c}*{box-sizing:border-box;margin:0;padding:0}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;background:#f0f2f5;min-height:100vh;display:flex;align-items:flex-start;justify-content:center;padding:3rem 1rem}