* {
    box-sizing: border-box;
}

body {
    min-height: 100vh;
}

body:not(.iframe-game-page) {
    padding-top: 48px;
}

.back-home {
    position: fixed;
    top: 12px;
    left: 12px;
    z-index: 10;
    color: #fff;
    text-decoration: none;
    font: 600 14px Arial, sans-serif;
    padding: 8px 10px;
    border-radius: 6px;
    background: rgba(0, 0, 0, 0.72);
}

.back-home:hover,
.back-home:focus {
    background: #00a6d6;
    color: #000;
}

.iframe-game-page {
    margin: 0;
    background: #000;
    color: #fff;
    overflow: hidden;
}

.iframe-game-page h1 {
    position: fixed;
    top: 52px;
    left: 12px;
    z-index: 2;
    margin: 0;
    font: 700 18px Arial, sans-serif;
    color: #fff;
    text-shadow: 0 2px 8px #000;
}

.iframe-game-page iframe {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    border: none;
}