ballz.js/style.css

body {
    width: 100%;
    height: 100%;
    margin: 0;
    background: #333;
}

* {
    color: #fff;
    font-family: Roboto, Arial, sans-serif;
    font-weight: 500;
}

.btn {
    padding: 10px 20px;
    border: none;
    border-radius: 10px;
    background: none;
    color: #fff;
    box-shadow: none;
    font-size: 16px;
    cursor: pointer;
}

.btn.primary {
    background: #2272ff;
}

.btn.danger {
    background: #F72754;
}

.container {
    display: block;
    width: 100%;
    max-width: 500px;
    margin: 10px auto;
}

.details {
    display: grid;
    grid-template-columns: 1fr 2fr 2fr 1fr 1fr;
}

.details h1, .details h3, .details .details-title {
    display: block;
    width: 100%;
    margin: 0;
    text-align: center;
}

.menu-btn-container {
    display: block;
}

.menu-btn-container .play-btn {
    position: relative;
    display: block;
    overflow: hidden;
    width: 20px;
    height: 20px;
    margin: 10px auto;
    cursor: pointer;
}

.menu-btn-container .play-btn::before, .menu-btn-container .play-btn::after {
    position: absolute;
    top: 0;
    z-index: -1;
    width: 51%;
    height: 100%;
    background: #ffffff;
    content: "";
    transition: .3s;
    will-change: transform;
}

.menu-btn-container .play-btn::before {
    left: 0;
}

.menu-btn-container .play-btn::after {
    right: 0;
}

.menu-btn-container .play-btn.paused::before {
    -moz-transform: translateX(-25%);
    -ms-transform: translateX(-25%);
    -o-transform: translateX(-25%);
    -webkit-transform: translateX(-25%);
    transform: translateX(-25%);
}

.menu-btn-container .play-btn.paused::after {
    transform: translateX(25%)
}

.menu-btn-container .play-btn.paused .pause-btn::before, .menu-btn-container .play-btn.paused .pause-btn::after {
    transform: rotate(0);
}

.menu-btn-container .play-btn .pause-btn::before, .menu-btn-container .play-btn .pause-btn::after {
    position: absolute;
    width: 150%;
    height: 100%;
    background: #333;
    outline: 1px solid transparent;
    content: "";
    transition: .3s;
}

.menu-btn-container .play-btn .pause-btn::before {
    top: -100%;
    transform: rotate(26.5deg);
    transform-origin: 0 100%;
}

.menu-btn-container .play-btn .pause-btn::after {
    top: 100%;
    transform: rotate(-26.5deg);
    transform-origin: 0 0;
}

.game-container {
    position: relative;
}

#canvas {
    display: block;
    margin: 20px auto;
    border-radius: 10px;
    background: rgba(255, 255, 255, .2);
}

.game-container .game-overlay {
    position: absolute;
    top: 0;
    left: 0;
    transform: translateY(100%);
    width: 100%;
    height: 100%;
    border-radius: 10px;
    background: #555;
    opacity: 0;
    pointer-events: none;
    transition: .3s;
}

.game-container .game-overlay.shown {
    transform: none;
    opacity: 1;
    pointer-events: all;
}

.game-container .game-overlay .game-overlay-title {
    margin: 45% 25px 50px;
    font-size: 25px;
    text-align: center;
}

.game-container .game-overlay .game-overlay-btns {
    display: block;
    width: 50%;
    margin: 25px auto;
}

.game-container .game-overlay .game-overlay-btns .btn {
    display: block;
    width: 100%;
    margin: 16px 0 0;
}