body{margin:0;padding:20px;font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif;transition:background-color .3s,color .3s}.app{max-width:600px;margin:0 auto}input[type=text]{border:1px solid #ccc;border-radius:5px;outline:none;width:70%;padding:10px;transition:border .2s}input[type=text]:focus{border-color:#007bff}button{color:#fff;cursor:pointer;background-color:#007bff;border:none;border-radius:5px;padding:8px 12px;transition:background-color .2s,transform .2s}button:hover{background-color:#0056b3;transform:translateY(-1px)}.todo-item{background-color:#0000000d;border-radius:8px;justify-content:space-between;align-items:center;margin:10px 0;padding:10px 15px;transition:background-color .3s,box-shadow .2s;display:flex;box-shadow:0 2px 5px #0000001a}.todo-item:hover{box-shadow:0 4px 10px #00000026}.todo-item input[type=checkbox]{cursor:pointer;width:18px;height:18px}.todo-item span{word-break:break-word;flex:1;margin-left:10px}body.light{color:#222;background-color:#f9f9f9}body.light .todo-item{background-color:#fff}body.dark{color:#f9f9f9;background-color:#222}body.dark .todo-item{background-color:#333}.theme-switcher{cursor:pointer;z-index:1000;align-items:center;gap:8px;display:flex;position:fixed;top:10px;right:10px}.theme-icon{width:28px;height:28px;transition:transform .3s}.theme-switcher:hover .theme-icon{transform:scale(1.2)}.todo-item span.done{opacity:.6;text-decoration:line-through;transition:opacity .3s}.todo-item{opacity:0;animation:.3s forwards fadeIn;transform:translateY(-10px)}@keyframes fadeIn{to{opacity:1;transform:translateY(0)}}