style.css

#window {
  background: black;
  height: 400px;
  width: 400px;
  border-radius:20px;
}

#ingameText {
  position:absolute;
  font-family:tahoma;
  color:white;
  top:45%;
  left:50%;
  transform:translate(-50%,-50%);
  -ms-transform:translate(-50%,-50%);
  text-align:center;
  font-size:25px;
  font-weight:bold;
}

#messageText {
  position:absolute;
  font-family:tahoma;
  font-weight:bold;
  font-size:15px;
  left:1%;
  bottom:1%;
}

#restartButton {
  color:black;
  background:orange;
  font-family:monospace;
  font-size:25px;
  position:absolute;
  top:2.5%;
  right:2.5%;
  cursor:pointer;
  padding-left:10px;
  padding-right:10px;
  border-radius:25px;
  font-weight:bold;
  box-shadow:0 0 4px orange;
}

#scoreDisplayer{
  font-family:monospace;
  font-weight:bold;
  font-size:25px;
  background:none;
  border:0;
  color:white;
  position:absolute;
  top:1%;
  left:1%;
  width:50%;
}

#scoreDisplayer:focus{
  outline:none;
}

.center {
  position: absolute;
  transform: translate(-50%, -50%);
  -ms-transform: translate(-50%, -50%);
  top: 50%;
  left: 50%;
  margin: 0;
}

.square {
  position: absolute;
  width: 50px;
  height: 50px;
  transform: translate(-50%, -50%);
  -ms-transform: translate(-50%, -50%);
  margin: 0;
}

#player {
  background: white;
  top: 90%;
  left: 50%;
}

.playerJumping {
  animation-name: jumpAni;
  animation-duration: 0.75s;
}
@keyframes jumpAni {
  0% {
    top:90%;
  }
  50% {
    top: 50%;
  }
  100% {
    top:90%;
  }
}

#block {
  background: red;
  top: 90%;
  left: 10%;
}
@keyframes blockAni {
  0% {
    left: 10%;
  }
  50% {
    left: 90%;
  }
  100% {
    left: 10%;
  }
}

.blockStartMoving {
  animation-name: blockAni;
  animation-duration:2s;
  animation-iteration-count: infinite;
  animation-timing-function:ease-in;
}