body {
    background-color: #f5f5f5;
    color: #333;
}

h1 {
    font-size: 2em;
    font-weight: normal;
    margin: 0.67em 0;
    color: black;
    font-weight: bold;
}

#application {
    width: 100%;
    height: 100%;
    background-color: #f0f0f0;
    position: relative;
    overflow: hidden;
    text-align: center;
}

#display {
    border: 1px solid #000;
    background-color: white;
}

#buttons {
    text-align: center;
}

table {
    background-color: black;
    border: 1px solid #000;
    border-collapse: collapse;
    margin: 0 auto;
    width: 25%;
}

td {
    height: 0.2em;
    width: 0.25em;
}

.function {
    background-color: yellow;
    border: 1px solid #000;
    border-collapse: collapse;
    margin: 0 auto;
}

.number {
    background-color: blue;
    border: 1px solid #000;
    border-collapse: collapse;
    margin: 0 auto;
}

.operation {
    background-color: red;
    border: 1px solid #000;
    border-collapse: collapse;
    margin: 0 auto;
}

button {
    background-color: #f0f0f0;
    border: 1px solid #000;
    border-collapse: collapse;
    margin: 0 auto;
    width: 25%;
}

button:hover {
    background-color: #000;
    color: #f0f0f0;
}