style.css

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.container{
    position: relative;
    max-width: 800px;
    height: 80vh;
    margin-top: 7rem;
    margin-left: 20rem;
    
}

h1{
    
    text-align: center;
}

#input-task{
    width: 600px;
    position: absolute;
    top: 70px;
    left: 0;
    padding-top: 2rem;
    border: none;
    border-bottom: 2px solid rgb(114, 71, 114);
    letter-spacing: .5rem;
    font-size: 15px;
    margin-left: 1rem;
}
#add-task-button{
    position: absolute;
    top: 70px;
    right: 60px;
    padding: 1rem;
    color:#fff;
    background-color: rgb(212, 185, 212);
    margin-left: .5rem;
    border: none;


}
.containers{
    position: absolute;
    top: 150px;
    margin-left: 1rem;
}
#task-list{
    list-style: none;
}
#task-list li{
    margin-bottom: 1.5rem;
}
.task{
    margin-left: 1.5rem;
}

.delete-btn{
    background-color: red;
    float: right;
    margin-left: 28rem;
    font-size: 18px;
    font-weight: 500;
    padding: .2rem;
    border: none;
    border-radius: 50%;
    color: #fff;
}
li input[type=checkbox]:checked{
    color: rgb(17, 84, 230);
}
ul li.checked{
    text-decoration: line-through;
}