editor/style.css

body,
html {
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #fff;
    font-family: sans-serif;
}

canvas {
    width: 100vw;
    height: 100vh;
}

dialog {
    width: 100%;
    text-align: center;
    max-width: 20em;
    color: white;
    background-color: #000;
    border: none;
    position: relative;
    transform: translate(-50%, -50%);
}

#progress-container {
    position: absolute;
    top: 50%;
    left: 50%;
}

progress {
    width: 100%;
    height: 1em;
    border: none;
    background-color: #fff;
    color: #eee;
}

progress::-webkit-progress-bar {
    background-color: #333;
}

progress::-webkit-progress-value {
    background-color: #eee;
}

progress::-moz-progress-bar {
    background-color: #eee;
}

#download-button {
    position: absolute;
    top: 8px;
    right: 8px;
    background-color: #000000cc;
    border: none;
    padding: 6px;
    margin: 0;
    border-radius: 2px;
    cursor: pointer;
}

#download-button:hover {
    background-color: #000000ee;
}

#download-button:active {
    background-color: #000000cc;
}

#download-button:focus {
    outline: none;
}