body{
font-family:Arial;
background:linear-gradient(135deg,#667eea,#764ba2);
height:100vh;
display:flex;
justify-content:center;
align-items:center;
}

.container{
background:white;
padding:25px;
border-radius:12px;
width:380px;
text-align:center;
box-shadow:0 10px 25px rgba(0,0,0,0.2);
}

input{
padding:10px;
width:65%;
border-radius:6px;
border:1px solid #ccc;
}

button{
padding:10px;
background:#667eea;
color:white;
border:none;
border-radius:6px;
cursor:pointer;
}

li{
list-style:none;
background:#f4f4f4;
padding:10px;
margin-top:10px;
border-radius:6px;
display:flex;
justify-content:space-between;
align-items:center;
}

.completed{
text-decoration:line-through;
color:gray;
}