* {
    margin: 0;
}
.calculator {
    display: flex;
    flex-direction: column;;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    min-width: 100vw;
    background-color: grey;

}
.screen {
    display: flex;
    height: 80px;
    width: 380px;
    padding: 10px;
    background-color: ghostwhite;
    border: 2px solid black;
    border-top-left-radius: 20px;
    border-top-right-radius: 20px;
    font-size: xx-large;
    align-items: flex-end;
    justify-content: flex-end;
    flex-wrap: wrap;
}
.keypad {
    display: flex;
    flex-wrap: wrap;
    height: 500px;
    width: 400px;
    border: 2px solid black;
    border-top: 0px;
    border-bottom-left-radius: 20px;
    border-bottom-right-radius: 20px;
}
button {
    height: 100px;
    width: 100px;
    font-size: xx-large;
    background-color: rgb(255, 199, 95);
}
.equal {
    font-weight: bolder;
    font-size: 50px;
    height: 100px;
    width: 300px;
    background-color: rgb(51, 255, 51);
    border-bottom-right-radius: 20px;
}
.back {
    color: red;
    font-weight: bold;
    font-size: 30px;
}
.clear {
    background-color: rgb(255, 68, 68);
    border-bottom-left-radius: 20px;
    font-size: 30px;
    font-weight: bold;
}