style.css

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    height : 100vh;
    display : flex;
}

button {
    border : 15px solid black;
    height: 280px;
    margin: 30px;
    padding : 0px;
}

.container {
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}

.top {
    background-color: black;
    display : flex;
    justify-content: center;
    align-items: center;
}

.content {
    background-color: #ffea00;
    font-size: xx-large;
    text-align: center;
    font-weight: bold;
    padding: 30px;
}

.UI {
    display : flex;
    flex-direction: column;
    background-color: #ffea00;
    height: auto;
    flex:1;
    justify-content: space-evenly;
    align-items: center;
}

#result {
    font-size: x-large;
    font-weight: bold;
    color : black;
}

#headerTitle {
    color : white;
}