style1.css

*{
    margin: 0;
    padding: 0;
    font-family: 'Poppins',sans-serif;
    box-sizing:border-box;
}

.container{
    width:100%;
    min-height:100vh;
   
background-color: #D9AFD9;
background-image: linear-gradient(0deg, #D9AFD9 0%, #97D9E1 100%);

    padding: 10px;
}
.todo-app{
    width:100%;
    max-width: 540px;
    background-color: #fff;
    margin:100px auto 30px;
    padding:40px 30px 70px;
    border-radius: 15px;
}
.todo-app h2{
    color:#002765;
    display:flex;
    align-items:center;
    margin-bottom: 20px;
}
.todo-app h2 img{
    width:31px;
    margin-left:11px;
}
.row{
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: #edeef0;
    border-radius:30px;
    padding-left:20px;
    margin-bottom: 25px;
}
input{
    flex:1;
    border:none;
    outline:none;
    background: transparent;
    padding: 10px;
    font-weight: 14px;
}
button{
    border: none;
    outline:none;
    padding:16px 50px;
   background-color:#7367F0;
  
    color: #fff;
    font-size: 16px ;
    cursor: pointer;
    border-radius: 40px;
}
ul li{
    list-style: none;
    font-size:17px;
    padding:12px 8px 12px 50px;
    user-select: none;
    cursor:pointer;
    position: relative;
}
ul li::before{
    content: '';
    position:absolute;
    height:28px;
    width:28px;
    border-radius:50%;
    background-image: url(To-Do-Img/images/unchecked.png);
    background-size: cover;
    background-position: center;
    top:12px;
    left:8px;
}
ul li.checked{
    color:#11192e;
    text-decoration: line-through;
}
ul li.checked::before{
    background-image: url(To-Do-Img/images/checked.png);
}
ul li span {
    position: absolute;
    right:0;
    top:5px;
    width: 40px;
    height: 40px;
    font-size:22px;
    color: #555;
    line-height: 40px;
    text-align: center;
    border-radius: 50%;

}
ul li span:hover{
    background: #edeef0;
}