checklist.css

body {
    background: linear-gradient(to right, #6441A5, #2a0845);
    min-height: 100%;
    font-family: sans-serif;
}

.todo{
    width: 480px;
    height: 455px;
    margin-left: 450px;
    margin-top: 220px;
    background-color: white;
    border: 5px solid #000;
}

.header{
    height: 80px;
    text-align: center;
    font-size: 3rem;
    font-weight: 10;
    background-color: orange;
    color: whitesmoke;
    padding-bottom: 10px;
    display: block;
    border-bottom: 5px solid black;
}

.desc{
    margin-top: -16px;
    height: 80%;
    margin-left: -40px;
}

input[type="checkbox"]{
    position: relative;
    top: 32px;
    right: 20px;
    float: right;

}

input[type="checkbox"]:checked+label {
    text-decoration: line-through;
    color: #fff;
    
}

.list{
    font-size: 30px;
    list-style-type: none;
}

.list li{
    float: left;
    width: 100%;
}

label {
    padding: 10px;
    float: left;
    width: 90%;
    
}

.orange{
    background-color: #ff6600;
    color: #ffff;
}

.light-orange{
    background-color: orange;
    color: #fff;
}

.checkbox{
    position: absolute;
    top: 0;
    left: 0;
    height: 25px;
    width: 25px;
    background-color: #eee;
}