styles.css

*{
    background-color: rgb(167, 23, 23);
    height: 100%;
}

.container{
    margin: auto;
    height:300px;
    width:500px;
    background-color: white;
    display: grid;
    grid-template-columns: 100px 1fr;
    grid-template-rows: 75px 75px 75px 75px;
    grid-template-areas: 
    ". bill"
    ". tipPercent"
    ". heads"
    ". sum"
    " button button";
    border-radius: 5 px;
}
.bill{
    grid-area: bill;
    height: 25 px;
    width: 250 px;
}
.tipPercent{
    grid-area: tipPercent;
    height: 25 px;
    width: 250 px;
}
.heads{
    grid-area: heads;
    height: 25 px;
    width: 250 px;
}
.Sum{
    grid-area: sum;
    height: 25 px;
    width: 250 px;
}    
.Submit{
    grid-area: button;
    height:75 px;
    width:auto;
    background-color: red;
    color:white;
    border-radius: 3px;
}