main.css

html, body {
    margin: 0;
    padding: 0;
    background: #faf8ef;
    color: #776e65;
    font-family: "Clear Sans", "Helvetica Neue", Arial, sans-serif;
    font-size: 18px;
  }
  
  body {
    margin: 20px 0;  
  }
  
  .heading:after {
    content: "";
    display: block;
    clear: both;
  }
  
  h1.title {
    font-size: 80px;
    font-weight: bold;
    margin: 0;
    display: block;
    float: left;
  }
  
  @-webkit-keyframes move-up {
    0% {
      top: 25px;
      opacity: 1;
    }
  
    100% {
      top: -50px;
      opacity: 0;
    }
  }
  @-moz-keyframes move-up {
    0% {
      top: 25px;
      opacity: 1;
    }
  
    100% {
      top: -50px;
      opacity: 0;
    }
  }
  @keyframes move-up {
    0% {
      top: 25px;
      opacity: 1;
    }
  
    100% {
      top: -50px;
      opacity: 0;
    }
  }
  .score-container {
    position: relative;
    float: right;
    background: #bbada0;
    padding: 15px 25px;
    font-size: 25px;
    height: 25px;
    line-height: 47px;
    font-weight: bold;
    border-radius: 3px;
    color: white;
    margin-top: 8px;
  }
  .score-container:after {
    position: absolute;
    width: 100%;
    top: 10px;
    left: 0;
    content: "Score";
    text-transform: uppercase;
    font-size: 13px;
    line-height: 13px;
    text-align: center;
    color: #eee4da;
  }
  .score-container .score-addition {
    position: absolute;
    right: 30px;
    color: red;
    font-size: 25px;
    line-height: 25px;
    font-weight: bold;
    color: rgba(119, 110, 101, 0.9);
    z-index: 100;
    -webkit-animation: move-up 600ms ease-in;
    -moz-animation: move-up 600ms ease-in;
    -webkit-animation-fill-mode: both;
    -moz-animation-fill-mode: both;
  }
  
  p {
    margin-top: 0;
    margin-bottom: 10px;
    line-height: 1.65;
  }
  
  a {
    color: #776e65;
    font-weight: bold;
    text-decoration: underline;
    cursor: pointer;
  }
  
  strong.important {
    text-transform: uppercase;
  }
  
  hr {
    border: none;
    border-bottom: 1px solid #d8d4d0;
    margin-top: 20px;
    margin-bottom: 30px;
  }
  
  .container {
    width: 500px;
    margin: 0 auto;
  }
  
  @-webkit-keyframes fade-in {
    0% {
      opacity: 0;
    }
  
    100% {
      opacity: 1;
    }
  }
  @-moz-keyframes fade-in {
    0% {
      opacity: 0;
    }
  
    100% {
      opacity: 1;
    }
  }
  @keyframes fade-in {
    0% {
      opacity: 0;
    }
  
    100% {
      opacity: 1;
    }
  }
  .game-container {
    margin-top: 10px;
    position: relative;
    padding: 15px;
    cursor: default;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    background: #bbada0;
    border-radius: 6px;
    width: 500px;
    height: 500px;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
  }
  .game-container .game-message {
    display: none;
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background: rgba(238, 228, 218, 0.5);
    z-index: 100;
    text-align: center;
    -webkit-animation: fade-in 800ms ease 1200ms;
    -moz-animation: fade-in 800ms ease 1200ms;
    -webkit-animation-fill-mode: both;
    -moz-animation-fill-mode: both;
  }
  .game-container .game-message p {
    font-size: 60px;
    font-weight: bold;
    height: 60px;
    line-height: 60px;
    margin-top: 222px;
  }
  .game-container .game-message .lower {
    display: block;
    margin-top: 59px;
  }
  .game-container .game-message a {
    display: inline-block;
    background: #8f7a66;
    border-radius: 3px;
    padding: 0 20px;
    text-decoration: none;
    color: #f9f6f2;
    height: 40px;
    line-height: 42px;
    margin-left: 9px;
  }
  .game-container .game-message.game-won {
    background: rgba(237, 194, 46, 0.5);
    color: #f9f6f2;
  }
  .game-container .game-message.game-won, .game-container .game-message.game-over {
    display: block;
  }

  .game-container .game-message.game-won, .game-container .game-message.game-over .lower {
    display: none;
  }
  
  .grid-container {
    position: absolute;
    z-index: 1;
  }
  
  .grid-row {
    margin-bottom: 15px;
  }
  .grid-row:last-child {
    margin-bottom: 0;
  }
  .grid-row:after {
    content: "";
    display: block;
    clear: both;
  }
  
  .grid-cell {
    width: 106.25px;
    height: 106.25px;
    margin-right: 15px;
    float: left;
    border-radius: 3px;
    background: rgba(238, 228, 218, 0.35);
  }
  .grid-cell:last-child {
    margin-right: 0;
  }
  
  .tile-container {
    position: absolute;
    z-index: 2;
  }
  
  .tile {
    width: 106.25px;
    height: 106.25px;
    line-height: 116.25px;
  }
  .tile.tile-position-1-1 {
    position: absolute;
    left: 0px;
    top: 0px;
  }
  .tile.tile-position-1-2 {
    position: absolute;
    left: 0px;
    top: 121px;
  }
  .tile.tile-position-1-3 {
    position: absolute;
    left: 0px;
    top: 243px;
  }
  .tile.tile-position-1-4 {
    position: absolute;
    left: 0px;
    top: 364px;
  }
  .tile.tile-position-2-1 {
    position: absolute;
    left: 121px;
    top: 0px;
  }
  .tile.tile-position-2-2 {
    position: absolute;
    left: 121px;
    top: 121px;
  }
  .tile.tile-position-2-3 {
    position: absolute;
    left: 121px;
    top: 243px;
  }
  .tile.tile-position-2-4 {
    position: absolute;
    left: 121px;
    top: 364px;
  }
  .tile.tile-position-3-1 {
    position: absolute;
    left: 243px;
    top: 0px;
  }
  .tile.tile-position-3-2 {
    position: absolute;
    left: 243px;
    top: 121px;
  }
  .tile.tile-position-3-3 {
    position: absolute;
    left: 243px;
    top: 243px;
  }
  .tile.tile-position-3-4 {
    position: absolute;
    left: 243px;
    top: 364px;
  }
  .tile.tile-position-4-1 {
    position: absolute;
    left: 364px;
    top: 0px;
  }
  .tile.tile-position-4-2 {
    position: absolute;
    left: 364px;
    top: 121px;
  }
  .tile.tile-position-4-3 {
    position: absolute;
    left: 364px;
    top: 243px;
  }
  .tile.tile-position-4-4 {
    position: absolute;
    left: 364px;
    top: 364px;
  }
  
  .tile {
    border-radius: 3px;
    background: #eee4da;
    text-align: center;
    font-weight: bold;
    z-index: 10;
    font-size: 55px;
    -webkit-transition: 100ms ease-in-out;
    -moz-transition: 100ms ease-in-out;
    -webkit-transition-property: top, left;
    -moz-transition-property: top, left;
  }
  .tile.tile-2 {
    background: #eee4da;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0), inset 0 0 0 1px rgba(255, 255, 255, 0);
  }
  .tile.tile-4 {
    background: #ede0c8;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0), inset 0 0 0 1px rgba(255, 255, 255, 0);
  }
  .tile.tile-8 {
    color: #f9f6f2;
    background: #f2b179;
  }
  .tile.tile-16 {
    color: #f9f6f2;
    background: #f59563;
  }
  .tile.tile-32 {
    color: #f9f6f2;
    background: #f67c5f;
  }
  .tile.tile-64 {
    color: #f9f6f2;
    background: #f65e3b;
  }
  .tile.tile-128 {
    color: #f9f6f2;
    background: #edcf72;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.2381), inset 0 0 0 1px rgba(255, 255, 255, 0.14286);
    font-size: 45px;
  }
  @media screen and (max-width: 480px) {
    .tile.tile-128 {
      font-size: 25px;
    }
  }
  .tile.tile-256 {
    color: #f9f6f2;
    background: #edcc61;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.31746), inset 0 0 0 1px rgba(255, 255, 255, 0.19048);
    font-size: 45px;
  }
  @media screen and (max-width: 480px) {
    .tile.tile-256 {
      font-size: 25px;
    }
  }
  .tile.tile-512 {
    color: #f9f6f2;
    background: #edc850;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.39683), inset 0 0 0 1px rgba(255, 255, 255, 0.2381);
    font-size: 45px;
  }
  @media screen and (max-width: 480px) {
    .tile.tile-512 {
      font-size: 25px;
    }
  }
  .tile.tile-1024 {
    color: #f9f6f2;
    background: #edc53f;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.47619), inset 0 0 0 1px rgba(255, 255, 255, 0.28571);
    font-size: 35px;
  }
  @media screen and (max-width: 480px) {
    .tile.tile-1024 {
      font-size: 15px;
    }
  }
  .tile.tile-2048 {
    color: #f9f6f2;
    background: #edc22e;
    box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.55556), inset 0 0 0 1px rgba(255, 255, 255, 0.33333);
    font-size: 35px;
  }
  @media screen and (max-width: 480px) {
    .tile.tile-2048 {
      font-size: 15px;
    }
  }
  
  @-webkit-keyframes appear {
    0% {
      opacity: 0;
      -webkit-transform: scale(0);
      -moz-transform: scale(0);
    }
  
    100% {
      opacity: 1;
      -webkit-transform: scale(1);
      -moz-transform: scale(1);
    }
  }
  @-moz-keyframes appear {
    0% {
      opacity: 0;
      -webkit-transform: scale(0);
      -moz-transform: scale(0);
    }
  
    100% {
      opacity: 1;
      -webkit-transform: scale(1);
      -moz-transform: scale(1);
    }
  }
  @keyframes appear {
    0% {
      opacity: 0;
      -webkit-transform: scale(0);
      -moz-transform: scale(0);
    }
  
    100% {
      opacity: 1;
      -webkit-transform: scale(1);
      -moz-transform: scale(1);
    }
  }
  .tile-new {
    -webkit-animation: appear 200ms ease 100ms;
    -moz-animation: appear 200ms ease 100ms;
    -webkit-animation-fill-mode: both;
    -moz-animation-fill-mode: both;
  }
  
  @-webkit-keyframes pop {
    0% {
      -webkit-transform: scale(0);
      -moz-transform: scale(0);
    }
  
    50% {
      -webkit-transform: scale(1.2);
      -moz-transform: scale(1.2);
    }
  
    100% {
      -webkit-transform: scale(1);
      -moz-transform: scale(1);
    }
  }
  @-moz-keyframes pop {
    0% {
      -webkit-transform: scale(0);
      -moz-transform: scale(0);
    }
  
    50% {
      -webkit-transform: scale(1.2);
      -moz-transform: scale(1.2);
    }
  
    100% {
      -webkit-transform: scale(1);
      -moz-transform: scale(1);
    }
  }
  @keyframes pop {
    0% {
      -webkit-transform: scale(0);
      -moz-transform: scale(0);
    }
  
    50% {
      -webkit-transform: scale(1.2);
      -moz-transform: scale(1.2);
    }
  
    100% {
      -webkit-transform: scale(1);
      -moz-transform: scale(1);
    }
  }
  .tile-merged {
    z-index: 20;
    -webkit-animation: pop 200ms ease 100ms;
    -moz-animation: pop 200ms ease 100ms;
    -webkit-animation-fill-mode: both;
    -moz-animation-fill-mode: both;
  }
  
  .game-intro {
    margin-bottom: 0;
  }
  
  .game-explanation {
    margin-top: 50px;
  }
  
  @media screen and (max-width: 480px) {
    html, body {
      font-size: 15px;
    }
  
    body {
      margin: 20px 0;
      padding: 0 20px;
    }
  
    h1.title {
      font-size: 50px;
    }
  
    .container {
      width: 280px;
      margin: 0 auto;
    }
  
    .score-container {
      margin-top: 0;
    }
  
    .heading {
      margin-bottom: 10px;
    }
  
    .game-container {
      margin-top: 40px;
      position: relative;
      padding: 10px;
      cursor: default;
      -webkit-touch-callout: none;
      -webkit-user-select: none;
      -moz-user-select: none;
      background: #bbada0;
      border-radius: 6px;
      width: 280px;
      height: 280px;
      -webkit-box-sizing: border-box;
      -moz-box-sizing: border-box;
      box-sizing: border-box;
    }
    .game-container .game-message {
      display: none;
      position: absolute;
      top: 0;
      right: 0;
      bottom: 0;
      left: 0;
      background: rgba(238, 228, 218, 0.5);
      z-index: 100;
      text-align: center;
      -webkit-animation: fade-in 800ms ease 1200ms;
      -moz-animation: fade-in 800ms ease 1200ms;
      -webkit-animation-fill-mode: both;
      -moz-animation-fill-mode: both;
    }
    .game-container .game-message p {
      font-size: 60px;
      font-weight: bold;
      height: 60px;
      line-height: 60px;
      margin-top: 222px;
    }
    .game-container .game-message .lower {
      display: block;
      margin-top: 59px;
    }
    .game-container .game-message a {
      display: inline-block;
      background: #8f7a66;
      border-radius: 3px;
      padding: 0 20px;
      text-decoration: none;
      color: #f9f6f2;
      height: 40px;
      line-height: 42px;
      margin-left: 9px;
    }
    .game-container .game-message.game-won {
      background: rgba(237, 194, 46, 0.5);
      color: #f9f6f2;
    }
    .game-container .game-message.game-won, .game-container .game-message.game-over {
      display: block;
    }
  
    .grid-container {
      position: absolute;
      z-index: 1;
    }
  
    .grid-row {
      margin-bottom: 10px;
    }
    .grid-row:last-child {
      margin-bottom: 0;
    }
    .grid-row:after {
      content: "";
      display: block;
      clear: both;
    }
  
    .grid-cell {
      width: 57.5px;
      height: 57.5px;
      margin-right: 10px;
      float: left;
      border-radius: 3px;
      background: rgba(238, 228, 218, 0.35);
    }
    .grid-cell:last-child {
      margin-right: 0;
    }
  
    .tile-container {
      position: absolute;
      z-index: 2;
    }
  
    .tile {
      width: 57.5px;
      height: 57.5px;
      line-height: 67.5px;
    }
    .tile.tile-position-1-1 {
      position: absolute;
      left: 0px;
      top: 0px;
    }
    .tile.tile-position-1-2 {
      position: absolute;
      left: 0px;
      top: 68px;
    }
    .tile.tile-position-1-3 {
      position: absolute;
      left: 0px;
      top: 135px;
    }
    .tile.tile-position-1-4 {
      position: absolute;
      left: 0px;
      top: 203px;
    }
    .tile.tile-position-2-1 {
      position: absolute;
      left: 68px;
      top: 0px;
    }
    .tile.tile-position-2-2 {
      position: absolute;
      left: 68px;
      top: 68px;
    }
    .tile.tile-position-2-3 {
      position: absolute;
      left: 68px;
      top: 135px;
    }
    .tile.tile-position-2-4 {
      position: absolute;
      left: 68px;
      top: 203px;
    }
    .tile.tile-position-3-1 {
      position: absolute;
      left: 135px;
      top: 0px;
    }
    .tile.tile-position-3-2 {
      position: absolute;
      left: 135px;
      top: 68px;
    }
    .tile.tile-position-3-3 {
      position: absolute;
      left: 135px;
      top: 135px;
    }
    .tile.tile-position-3-4 {
      position: absolute;
      left: 135px;
      top: 203px;
    }
    .tile.tile-position-4-1 {
      position: absolute;
      left: 203px;
      top: 0px;
    }
    .tile.tile-position-4-2 {
      position: absolute;
      left: 203px;
      top: 68px;
    }
    .tile.tile-position-4-3 {
      position: absolute;
      left: 203px;
      top: 135px;
    }
    .tile.tile-position-4-4 {
      position: absolute;
      left: 203px;
      top: 203px;
    }
  
    .game-container {
      margin-top: 20px;
    }
  
    .tile {
      font-size: 35px;
    }
  
    .game-message p {
      font-size: 30px !important;
      height: 30px !important;
      line-height: 30px !important;
      margin-top: 90px !important;
    }
    .game-message .lower {
      margin-top: 30px !important;
    }