.container{max-width:400px;margin:40px auto;padding:30px;background:#fff;border-radius:16px;box-shadow:0 4px 20px #0000001a}.container h1{margin:0 0 20px;text-align:center}.input-box{display:flex;gap:8px;margin-bottom:20px}.input-box input{flex:1;padding:12px;border:2px solid #ddd;border-radius:8px;font-size:14px}.input-box input:focus{outline:none;border-color:#7c3aed}.input-box button{padding:12px 20px;background:#7c3aed;color:#fff;border:none;border-radius:8px;cursor:pointer}.input-box button:hover{background:#6d28d9}.todo-list{list-style:none;padding:0;margin:0}.todo-list li{display:flex;align-items:center;gap:10px;padding:12px;border-bottom:1px solid #eee}.todo-list li span{flex:1}.todo-list li button{background:none;border:none;cursor:pointer;opacity:.5}.todo-list li button:hover{opacity:1}.todo-list li.completed span{color:#999;text-decoration:line-through}