body {
  background: url("../images/tetris-background.jpeg") no-repeat fixed;
  background-size: cover;
}

#tetris {
  width: 320px;
  margin: 0 auto;
  position: relative;
}

#imagen {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
}

.game-board {
  width: 200px;
  height: 400px;
  position: relative;
  margin-top: 232px;
}

.score {
  position: absolute;
  top: 0;
  left: 47%;
  transform: translateX(-47%);
  margin-top: 128px;
  padding: 10px 20px;
  font-size: 32px;
  font-weight: bold;
  color: #000;
  text-shadow: -1px -1px 0 white, 1px -1px 0 white, -1px 1px 0 white, 1px 1px 0 white;
}

.game-board .cell {
  width: 20px;
  height: 20px;
  background-color: #000;
  border: 1px solid #CCC;
  position: absolute;
}

.game-board .piece-cell {
  background-color: grey;
}

.piece {
  position: absolute;
}

#start-button,
#pausa {
  display: inline-block;
  margin-top: 20px;
  padding: 10px 20px;
  font-size: 18px;
  font-weight: bold;
  color: #fff;
  background-color: #333;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

#start-button:hover,
#pausa:hover {
  background-color: #555;
}

#start-button:focus,
#pausa:focus {
  outline: none;
}

.controls {
  display: none;
  justify-content: space-between;
}
.controls i {
  padding: 25px 0;
  text-align: center;
  font-size: 1.3rem;
  color: #FFF;
  width: calc(100% / 4);
  cursor: pointer;
  border-right: 1px solid #171B26;
}

@media screen and (max-width: 900px) {
  .controls {
    display: flex;
    background-color: #000;
    left: 12%;
    transform: translateX(-12%);
  }
  .controls i {
    padding: 15px 0;
    font-size: 1rem;
  }
}