styles.css

body {
  margin: 0;
  color: white;
}

main {
  position: absolute;
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
  height: 100%;
  background-image: url("../background.webp");
  background-repeat: no-repeat;
  background-size: cover;
  z-index: 12;
}

.score {
  position: absolute;
  top: 10px;
  left: 10px;
  font-size: 2em;
  z-index: 100;
  display: none;
  width: 100%;
  margin: 0;
  font-family: "Bangers", cursive;
}

.score-number {
  display: inline-block;
  margin: 0;
}

.lose {
  right: 1em;
  position: absolute;
  top: 0;
}

.game {
  position: absolute;
  z-index: 100;
  width: 100%;
  height: 100%;
}

video {
  position: absolute;
  z-index: -10;
  width: 100%;
  height: 100%;
  transform: scaleX(-1);
  -moz-transform: scaleX(-1);
  -o-transform: scaleX(-1);
  -webkit-transform: scaleX(-1);
}

canvas#output {
  position: absolute;
  width: 100%;
  height: 100%;
  z-index: 15;
  transform: scaleX(-1);
  -moz-transform: scaleX(-1);
  -o-transform: scaleX(-1);
  -webkit-transform: scaleX(-1);
}

.intro {
  font-family: "Trebuchet MS", "Lucida Sans Unicode", "Lucida Grande",
    "Lucida Sans", Arial, sans-serif;
  display: block;
  z-index: 130;
  text-align: center;
  width: 60%;
}

.intro h1 {
  font-size: 6em;
  color: yellow;
  text-shadow: 3px 3px 3px black;
  font-family: "Bangers", Helvetica;
  letter-spacing: 5px;
  margin: 0;
}

.game-over {
  display: none;
  font-size: 6em;
  text-shadow: 3px 3px 3px black;
  font-family: "Bangers", Helvetica;
  letter-spacing: 5px;
  margin: 0;
  position: absolute;
  justify-content: center;
  align-items: center;
  width: 100%;
  height: 100%;
  z-index: 100;
}

.intro p {
  font-size: 1.4em;
  text-shadow: 1px 1px 3px black;
}

.intro p:last-of-type {
  margin-bottom: 2em;
}

.intro button {
  padding: 0.4em 1em;
  font-size: 1.3em;
  border-radius: 3px;
  border: none;
}

.intro button:hover {
  cursor: pointer;
}

.mobile-intro {
  display: none;
  font-family: Helvetica;
  width: 90%;
  text-align: center;
  line-height: 1.5em;
}