*{box-sizing:border-box;margin:0;padding:0;font-family:sans-serif}body{background:#f4f4f4;display:flex;justify-content:center;padding:40px 16px}.container{background:#fff;padding:32px;border-radius:8px;width:100%;max-width:480px;box-shadow:0 2px 8px #0000001a;display:flex;flex-direction:column;gap:16px}.header{display:flex;justify-content:space-between;align-items:center}input[type=text],input[type=password]{width:100%;padding:10px;border:1px solid #ddd;border-radius:4px}button{padding:10px 16px;background:#1976d2;color:#fff;border:none;border-radius:4px;cursor:pointer}button:hover{background:#1565c0}.error{color:red;font-size:14px}.success{color:green;font-size:14px}ul{list-style:none;display:flex;flex-direction:column;gap:8px}li{display:flex;align-items:center;gap:8px;padding:8px;border:1px solid #eee;border-radius:4px}li span{flex:1}.done{text-decoration:line-through;color:#999}.new-task{display:flex;flex-direction:column;gap:8px}