style.css

*{
    padding:0;
    margin:0;
}

html, body #fullheight{
    min-height: 100% !important;
    height: 100%;
    font-family: Arial, Helvetica, sans-serif;
    background: black;
}
.conatiner{
    height: 100%;
    background-color: black;
}
.result{
    display: flex;
    justify-content: flex-end;
    align-items: flex-end;
    color: white;
    height: 39%;
}
.result span{
    margin-top: 300px;
    margin-right: 20px;
    font-size: 105px;
    justify-content: flex-end;
}
.buttons{
    width: 100%;
    height: 60%;
    background-color: black;
    display: grid;
    grid-template-columns: 25% 25% 25% 25%;
}
.item{
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 37px;
    color: white;
    border-radius: 100%;
    width: 80px;
    height: 80px;
    padding: 10px;
    cursor: pointer;
    align-self: center;
    justify-self: center;
    margin-top: 10px;
}
.percent{
    background-color: #A5A5A5;
    border: none;
    color: black;
}
.item1 {
    background-color: #A5A5A5;
    border: none;
}
.item3{
    background-color: #FF9F0A;
    border: none;
}
button.item.equals{
    background-color: #FF9F0A;
    border: none;
}
.numbers, .comma{
    background-color: #343434;
    border: none;
}

.negative, .clear{
    color: black;
}
.itemZero{
    background-color: #343434;
    border-radius: 135px;
    grid-column: span 2;
    border: none;
    width: 170px;
}