style.css

.menu {
  margin: 5rem auto;
  display: flex;
  flex-direction: column;
  position: relative;
}

.menu a {
  margin: 1rem 0;
}

/* posistion the .home-button class at the top right WITHIN the menu class*/
.home-button {
  position: absolute;
  right: -0.5rem;
  top: -0.5rem;
}

.clicked {
  background-color: #f5f5f5 !important;
}

.game-bar {
  display: flex;
  justify-content: space-between;
}
.game-bar div {
  float: left;
}
.game-bar div:last-child {
  float: right;
  font-size: 2rem;
  align-items: center;
}
/* viewport for smaller than 48rem */
@media (max-width: 48rem) {
  /* set max-width for body and center it */
  .menu {
    max-width: 20rem;
  }

  /* add spacing between buttons */
  .menu a {
    margin: 1rem;
  }

  h1 {
    font-size: 1.5rem;
  }
  .game-bar div:last-child {
    font-size: 1.5rem;
  }
}

/* desktop viewport */
@media (min-width: 48rem) {
  .menu {
    max-width: 40rem;
  }

  h1 {
    font-size: 2rem;
  }
  .home-button {
    right: -0.75rem;
    top: -0.75rem;
  }
}

.transformation-matrix {
  /* 3x3 grid */
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-gap: 1rem;
  /* center the grid */
  justify-items: center;
  align-items: center;
  /* text center */
  text-align: center;
}

#game-subheader {
  display: flex;
  justify-content: space-between;
}

#score {
  font-size: 3rem;
}

#game-over {
  /* center text */
  text-align: center;
}

#game-over > h2 {
  color: red;
  /* set to blinking animation */
  animation: blink 0.5s infinite;
}