style.css

body{
    display: flex;
    justify-content: center;
    font-family: 'Manrope', sans-serif;
    background-color: #323638;
}
section#calculator{
    width: 400px;
    box-shadow: 2px 2px 2px rgba(30, 35, 38, 0.686);
    background-color: #f0f0f0;
}
.format{
    width: 88%;
    text-align: end;
    margin-left: 5%;
    outline: none;
}
div#results{
    font-size: 45px;
    height: 70px;
    overflow: auto;
    padding-bottom: 12px;
}
div#calc{
    font-size: 22px;
    padding-top: 10px;
    overflow: auto;
    height: 45px;
}
div#line{
    display: flex;
    flex-direction: row;
}
.btn{
    color: white;
    width: 100px;
    font-size: 25px;
    font-weight: lighter;
    height: 99px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    -webkit-user-select: none;
}
.btn:hover{
    background-color: rgb(211, 210, 210);
    color: black;
}

.btn:active{
    background-color: #fff;
    color: black;
}
.grey{
    background-color: #1e2326;
    border: 1px solid #282d30;
}
.blue{
    background-color: #247BA0;
    border: 1px solid #1d98cc;
}
.orange{
    background-color: #ff8a15;
    border: 1px solid #ff9c39;
}

button{
    cursor: pointer;
    border: transparent;
    background: transparent;
    padding: 0;
    outline: 0;
}