#container {
    width: 400px;
    display: flex;
    position: relative;
    margin: auto;
    padding: 30px;
    background: #a9a9a9;
    border-radius: 30px;
    margin-top: 30px;
}

button {
    height: 70px;
    border: none;
    border-radius: 10px;
    margin: 3px;
    font-size: large;
}

#buttongrid{
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    width: 100%;
    grid-gap: 10px;
}

#clear{
    grid-column: 1/3;
}

#backspace{
    grid-column: 3/5;
}

#screen {
    margin: 3px;
    text-align: right;
    vertical-align: auto;
    margin-bottom: 10px;
    height: 100px;
    border-radius: 10px;
    background-color: aliceblue;
    grid-column: 1/5;
    font-family: Arial, Helvetica, sans-serif;
}

#history{
    height: 26px;
    margin: 0px;
    margin-top: 10px;
    margin-right: 10px;
    font-size: 20px;
}

#display{
    margin: 0px;
    font-size: 50px;
    margin-right: 10px;
}

.keydown{
    background-color: #585858;
}