.main {
    display: grid;
    justify-content: center;
}

button {
    width: 100px;
    height: 100px;
    font-size: 24px;
    font-weight: bold;
    background-color: lightblue;
    border: black solid;
    padding: 0;
}

#C, #\= {
    grid-area: span 1 / span 2;
    width: 200px;
}

.zero {
    grid-area: span 1 / span 3;
    width: 300px;
}

button:hover {
    background-color: lightsteelblue;
}

button:active {
    background-color: white;
}

#displayTop {
    border-top: black solid;
}

#displayBottom {
    border-bottom: black solid;
}

#displayTop, #displayBottom {
    grid-area: span 1 / span 5;
    width: 494px;
    height: 47px;
    border-left: black solid;
    border-right: black solid;
    background-color: mintcream;
    font-size: 24px;
    font-weight: bold;
    padding: 0;
}

#equation, #result {
    font-size: 36px;
    font-weight: bold;
}