:root {
  --clr-txt: #fff;
  --clr-background:#000;
  --game-width: 640px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  user-select: none;
}

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: 'Orbitron', sans-serif;
  color: var(--clr-txt);
  background-color: var(--clr-background);
  margin: 0;
}

.game-area {
  width: var(--game-width);
  height: 480px;
  position: relative;
  background: var(--clr-background) url(/imgs/space-bg.jpg) no-repeat center;
  overflow: hidden;
}

.ship {
  --width: 60px;
  width: var(--width);
  height: 50px;
  position: absolute;
  bottom: 2%;
  left: 290px;
}

.alien {
  width: 40px;
  height: 40px;
  position: absolute;
  top: 0;
}

.laser-beam {
  width: 10px;
  height: 30px;
  position: absolute;
  bottom: 65px;
  left: 315px;
}

.dead-alien {
  width: 40px;
  height: auto;
  position: absolute;
  opacity: 1;
}

.score {
  position: absolute;
  top: 0;
  right: 3%;
  font-size: 1rem;
}

.container {
  position: absolute;
  top: 40%;
  left: 50%;
  transform: translate(-50%, -50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.instruction {
  font-size: 1rem;
  text-transform: lowercase;
}

.title {
  font-size: 2.5rem;
  font-weight: 700;
  text-transform: uppercase;
  margin: 0;
}

.hide {
  display: none;
}