:root {
    --header-background-color: #171717;
    --header-text-color: white;
    --header-button-background-color: #676767;
    --header-button-color: #eaeaea;
    --aside-background-color: #dfdfdf;
    --aside-text-color: #000;
    --box-padding: 1em;
}
html, body {
    height: 100%;
}
body {
    display: flex;
    flex-direction: column;
    font-family: sans-serif;
    margin: 0;
    padding: 0;
}
header {
    display: flex;
    background-color: var(--header-background-color);
    color: var(--header-text-color);
    padding: .5em;
}
header h1 {
    margin: 0;
    padding: 0;
    transform: translateY(-.1em);
    user-select: none;
    font-size: 1.1em;
}
header button {
    margin-left: auto;
    background-color: var(--header-button-background-color);
    color: var(--header-button-color);
}
header h1 > span.emoji {
    padding-right: .4em;
}
header h1 > span.emoji:before {
    content: "🍺";
}
.slot {
    display: flex;
    flex-direction: row;
    width: 100%;
    height: 100%;
}
aside.calculator {
    display: flex;
    flex: 1 0 0;
    background-color: var(--aside-background-color);
    height: 100%;
    box-shadow: 0 0 10px rgba(0, 0, 0, .5);
}
main.controls {
    display: flex;
    flex: 4 0 0;
}
aside.calculator > div,
main.controls > div {
    padding: var(--box-padding);
    box-sizing: border-box;
}