* {
    margin: 0;
    font-family: Arial
}

/* Make calc and history sections side by side */
main {
    display: flex;
    gap: 40px;
    margin: 10px;
}


#display {
    margin-top: 5px;
    height: 25px;
    padding: 3px;
    margin-bottom: 20px;
    border: 2px solid black;
    box-sizing: border-box;
    text-align: right;
}

#button-grid {
    display: grid;
    grid-template-columns: repeat(4, 25px);
    gap: 15px;
}

#button-grid button {
    width: 25px;
    height: 25px;
    padding: 0;
    background-color: white;
    border: 2px solid black;
    box-shadow: 2px 2px 0 black;
}

/* long button */
#equals {
    width: 145px;
    height: 30px;
    margin-top: 15px;
    background-color: white;
    border: 2px solid black;
    box-shadow: 2px 2px 0 black;
}

/* History */
#history {
    width: 160px;
}

#history-box {
    height: 170px;
    border: 2px solid black;
    box-sizing: border-box;
    overflow-y: scroll;
}

.history-entry {
    height: 20px;
    padding-left: 5px;
    box-sizing: border-box;
}

.history-entry:nth-child(odd) {
    background-color: lightgray;
}

.history-entry:nth-child(even) {
    background-color: white;
}

#clear-history {
    height: 25px;
    margin-top: 15px;
    margin-left: 30px;
    background-color: white;
    border: 2px solid black;
    box-shadow: 2px 2px 0 black;
}