*,
*::before,
*::after {
    box-sizing: border-box
}

html,
body {
    min-height: 100vh;
    padding: 0;
    margin: 0
}

body {
    color: #222;
    line-height: 1.2
}

#welcome-message {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 640px;
    max-width: 100%;
    padding: 48px;

    z-index: 20;
    opacity: 1;
    transition: opacity .2s ease;
}

#welcome-message.hidden {
    pointer-events: none;
    opacity: 0;
}

.container {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 640px;
    max-width: 100%;
    padding: 48px;
    text-align: center;
}

canvas#result {
    /* needs position: absolute so it's rendered above the video */
    position: absolute;
    z-index: 10;
}

video#capture {
    max-width: 100%;
    height: auto;
}

canvas#result,
video#capture {
    transform: scale(-1, 1)
}