style.css

body {
    background-color: rgb(43, 43, 43);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 24px;
    color: orange;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}

.calculator {
    width: 360px;
    height: 500px;
    background-color: rgb(66, 66, 66);
    border: solid 5px orange;
    border-radius: 10px;
}

.display {
    width: 100%;
    height: 142px;
    text-align: end;
}

.row {
    display: flex;
}

.btn {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 90px;
    height: 70px;
    background-color: rgb(52, 52, 52);
    border: solid 1px black;
}

.equal {
    
    border-radius: 0px 0px 5px 0px;
}

.dot {
    border-radius: 0px 0px 0px 5px;
}

.head {
    display: flex;
    justify-content: end;
    align-items: center;
    padding-right: 15px;
    padding-top: 5px;
    height: 50px;
    border-radius: 5px 5px 0px 0px;
}

.main {
    display: flex;
    justify-content: end;
    align-items: end;
    height: 83px;
    padding: 0px 15px 0px 0px;
    font-size: 54px;
}
.num{
    background-color: rgb(41, 41, 41);
}