body{font-family:Arial,sans-serif;background:#f9fafb;display:flex;justify-content:center;padding:40px}.app-container{background:#fff;padding:20px 30px;border-radius:8px;width:400px;box-shadow:0 4px 10px #0000001a}h1{text-align:center;margin-bottom:20px}.task-input{display:flex;gap:10px}.task-input input{flex:1;padding:8px}.task-input button{padding:8px 12px;cursor:pointer}.task-list{margin-top:20px;list-style:none;padding:0}.task-item{display:flex;align-items:center;gap:10px;margin-bottom:8px;padding:6px;border-radius:4px;background:#f1f3f4}.task-item.completed span{text-decoration:line-through;color:gray}.task-item button{background:transparent;border:none;cursor:pointer}.empty{text-align:center;margin-top:20px;color:gray}