tetris.js/style.css

body {
    overflow: hidden;
    margin: 0;
    padding: 0;
    background: #202028;
    color: #fff;
    font-family: Roboto, Helvetica, Arial, sans-serif;
    font-size: 2.5em;
}

.menu {
    position: absolute;
    -moz-transform: scale(.5);
    -ms-transform: scale(.5);
    -o-transform: scale(.5);
    -webkit-transform: scale(.5);
    transform: scale(.5);
    z-index: 1;
    width: 3.5rem;
    height: 2.7rem;
    padding: 0;
    border: 0;
    background: 0;
    outline: 0;
    -webkit-transition: 0.1s -webkit-transform linear;
    transition: 0.1s -webkit-transform linear;
    transition: 0.1s transform linear;
    transition: 0.1s transform linear, 0.1s -webkit-transform linear;
    float: left;
}

#menu {
    position: fixed;
    top: 0;
    transform: translateX(-100%);
    z-index: 100;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, .75);
    -moz-transition: transform .5s;
    -ms-transition: transform .5s;
    -o-transition: transform .5s;
    -webkit-transition: transform .5s;
    transition: transform .5s;
}

#menu-content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    overflow: auto;
    width: 375px;
    max-width: 100%;
    max-height: 90%;
    font-size: .6em;
}

#menu-content > * {
    padding: 20px;
    border-bottom: 1px solid #444;
}

#menu-content > *:last-child {
    border: none;
}

#menu-content h3 {
    margin: 0 0 15px;
}

#help-controls dl {
    height: 273px;
    margin: 0;
}

#help-controls dt {
    width: 30%;
    margin-bottom: 10px;
    float: left;
}

#help-controls dt code {
    padding: 5px 10px;
    border-radius: 5px;
    background: rgba(255, 255, 255, 1);
    color: #000;
}

#help-controls dd {
    width: 70%;
    margin: 0 0 10px;
    float: left;
}

.menu-open #menu {
    transform: none;
}

#menu-opener {
    position: absolute;
    top: 10px;
    left: 10px;
    z-index: 101;
}

.lang {
    display: inline;
    margin-left: 10px;
    padding: 4px 8px;
    border-radius: 2px;
    cursor: pointer;
}

.lang.active {
    background-color: #3877FF;
}

#game-title {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -25%) translateY(-200px);
    opacity: 1;
    transition: opacity .5s;
}

#game-play, #game-reset {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 300px;
    height: 75px;
    border: 0 !important;
    border-radius: 0 !important;
    background: #3877FF !important;
    color: #ffff !important;
    box-shadow: none;
    opacity: 1;
    font-size: 30px;
    cursor: pointer;
    transition: box-shadow .2s, opacity .5s;
    -webkit-text-fill-color: #fff;
}

#game-reset {
    transform: translate(-50%, -50%) translateY(85px);
    display: none;
    background-color: #FF0D72 !important;
    opacity: 0;
}

#game-play {
    z-index: 10;
}

#game-play:hover, #game-play:active, #game-play:focus {
    box-shadow: 3px 4px 0 3px rgba(0, 0, 0, 0.2) !important;
    outline: none !important;
}

#background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    filter: url(#f2);
}

.blurred {
    filter: url(#f1);
}

#canvas-container {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 761px;
    height: 936px;
}

#tetris, #tetris-background {
    position: absolute;
    top: 50%;
    left: 50%;
    -moz-transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    -o-transform: translate(-50%, -50%);
    -webkit-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
    z-index: 1;
    border: solid .2em #fff;
    background: transparent;
}

#tetris-background {
    z-index: 0;
    border: none;
}

#tetris-hold {
    position: absolute;
    left: 50%;
    border: solid .2em #fff;
}

#tetris-upcoming {
    position: absolute;
    right: 50%;
    border: solid .2em #fff;
}

/*.game-stats {*/
/*    position: absolute;*/
/*    bottom: 3.75vh;*/
/*    left: 50%;*/
/*    transform: translateX(-50%);*/
/*    font-size: 2.5vh;*/
/*}*/
/**/
/*#score {*/
/*    top: 2.5vh;*/
/*    bottom: initial;*/
/*    font-size: 5vh;*/
/*    font-weight: 900;*/
/*}*/
/**/
#score.update {
    animation: scoreUpdate .5s;
}

@keyframes scoreUpdate {
    0% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.5);
    }

    100% {
        transform: scale(1);
    }
}

#time:before, #score:before {
    content: attr(data-prefix);
}

#controls {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) translateX(30vw);
    max-width: 20vw;
    font-size: 20px;
}

.game-over #score {
    top: 50%;
}

#footer {
    position: absolute;
    right: 2.5%;
    bottom: 10px;
    left: 2.5%;
    width: 95%;
    color: rgba(255, 255, 255, .5);
    font-size: 12px;
}

#version-author {
    display: inline-block;
}

#corner-buttons {
    position: absolute;
    right: 0;
    display: inline-block;
}

#corner-buttons > a {
    left: 10px;
    display: inline-block;
    color: rgba(255, 255, 255, .5);
    -moz-transition: color .2s;
    -ms-transition: color .2s;
    -o-transition: color .2s;
    -webkit-transition: color .2s;
    transition: color .2s;
    text-decoration: none;
}

#corner-buttons > a:hover, #corner-buttons > a:active {
    color: rgba(255, 255, 255, 1);
}

.bar, .bar::before, .bar::after {
    position: absolute;
    top: 50%;
    left: 0;
    width: 100%;
    height: 0.3rem;
    margin: auto;
    background: #fff;
    content: '';
    -webkit-transition: 0.2s background linear 0.1s, 0.2s top linear 0.2s, 0.2s -webkit-transform linear;
    transition: 0.2s background linear 0.1s, 0.2s top linear 0.2s, 0.2s transform linear;
}

.bar {
    margin-top: -0.2rem;
}

.bar::before {
    top: -1.2rem;
}

.bar::after {
    top: 1.2rem;
}

.bar::before, .bar::after {
    -webkit-transform: rotate(0deg);
    transform: rotate(0deg);
}

.active .bar {
    background: 0;
}

.active .bar::before {
    -webkit-transform: rotate(45deg);
    transform: rotate(45deg);
}

.active .bar::after {
    -webkit-transform: rotate(-45deg);
    transform: rotate(-45deg);
}

.active .bar::before, .active .bar::after {
    top: 0;
}

.active .bar, .active .bar::before, .active .bar::after {
    -webkit-transition: 0.2s background linear 0.1s, 0.2s top linear, 0.2s -webkit-transform linear 0.2s;
    transition: 0.2s background linear 0.1s, 0.2s top linear, 0.2s -webkit-transform linear 0.2s;
    transition: 0.2s background linear 0.1s, 0.2s top linear, 0.2s transform linear 0.2s;
    transition: 0.2s background linear 0.1s, 0.2s top linear, 0.2s transform linear 0.2s, 0.2s -webkit-transform linear 0.2s;
}

/*
Radio Buttons
 */

.radio {
    margin: 0.5rem;
}

.radio input[type="radio"] {
    position: absolute;
    opacity: 0;
}

.radio input[type="radio"] + .radio-label:before {
    position: relative;
    top: -0.2em;
    display: inline-block;
    width: 1.4em;
    height: 1.4em;
    margin-right: 1em;
    border: 1px solid #b4b4b4;
    border-radius: 100%;
    background: #f4f4f4;
    content: '';
    text-align: center;
    cursor: pointer;
    -webkit-transition: all 250ms ease;
    transition: all 250ms ease;
    vertical-align: top;
}

.radio input[type="radio"]:checked + .radio-label:before {
    background-color: #3197EE;
    -webkit-box-shadow: inset 0 0 0 4px #f4f4f4;
    box-shadow: inset 0 0 0 4px #f4f4f4;
}

.radio input[type="radio"]:focus + .radio-label:before {
    border-color: #3197EE;
    outline: none;
}

.radio input[type="radio"]:disabled + .radio-label:before {
    border-color: #b4b4b4;
    background: #b4b4b4;
    -webkit-box-shadow: inset 0 0 0 4px #f4f4f4;
    box-shadow: inset 0 0 0 4px #f4f4f4;
}

.radio input[type="radio"] + .radio-label:empty:before {
    margin-right: 0;
}

/* Game */
.game-container {
    display: flex;
    height: calc(100vh - 40px);
}

.game-instance {
    flex-grow: 1;
}

.score {
    margin: 10px 0;
    font-size: 40px;
    text-align: center;
}

.score.update {
    animation: scoreUpdate .5s;
}

.time {
    font-size: 25px;
    text-align: center;
    margin: 10px 0;
}

.canvas-container {
    position: relative;
    display: block;
    width: 80%;
    margin: 0 auto;
}

.tetris-hold {
    position: absolute;
    top: 0;
    left: 0;
    width: 20%;
}

.tetris-arena, .tetris-background {
    position: absolute;
    top: 0;
    left: 20%;
    width: 60%;
    height: 100%;
}

.tetris-upcoming {
    position: absolute;
    top: 0;
    right: 0;
    width: 20%;
}