style.css

#main {
    border: 1px solid black;
    background-color: rgb(101, 178, 24); 
    z-index: 1;
}

canvas {
    pointer-events: none;
}

.main {
    width: 100%;
    height: 100%;
    padding: 0;
    margin: 0;
    zoom: 100%
}

html {
    margin:0;
    padding:0;
}

body {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh;
    margin:0;
    padding:0;
}

#data {
    display: none;
}

#upgrades {
    z-index: 1;
    position: fixed;
    display: none;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 1;
    background-color: rgba(0, 0, 0, 0.3);
    padding: 10px;
    border-radius: 10px;
    color: white;
    font-size: 16px;
    width: 50%;
    height: 75%;
    text-align: left;
    zoom: 200%;
}

#buttonGrid {
    position: relative;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-gap: 10px;
    margin-top: 10px;
    padding: 15px;
    zoom: 100%;
    height: 85%;
    overflow-y: auto;
}

#overlay {
    z-index: 1;
    position: fixed;
    display: none;
    top: 50%;
    left: 50%;
    font-family: 'Courier New', monospace;
    transform: translate(-50%, -50%);
    z-index: 1;
    background-color: rgba(0, 0, 0, 0.3);
    padding: 10px;
    border-radius: 10px;
    color: white;
    font-size: 16px;
    width: 50%;
    height: 75%;
    text-align: center;
    zoom: 100%;
    overflow: auto;
}

.button {
    width: 100%;
    height: 150px;
    padding: 10px;
    color: white;
    text-align: top;
    background-color: rgba(0, 0, 0, 0.5);
    border: none;
    border-radius: 5px;
    white-space: pre-line;
}

#big {
    /* grid display */
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    /* rows */
    grid-template-rows: 1fr 1fr;
    grid-gap: 10px;
    /* height of elements */
    height: 12rem;
    /* padding/margin */
    padding: 10px;
    margin: 10px;
}

#big button {
    border-radius: 5px;
    outline: none;
    /* no button decorations */
    border: none;
    /* background color */
    cursor: pointer;
}

#big button:hover {
    background-color: rgba(0, 0, 0, 0.1);
}