* {
  box-sizing: border-box;
}

body {
  margin: 0;
}

.clickable-area {
  height: 100vh;
  width: 100%;
  cursor: pointer;
  background: limegreen;
  display: grid;
  place-items: center;
  font-size: 32px;
  font-family: "Roboto", sans-serif;
  color: #fff;
}

.end-screen,
.main-menu {
  display: none;
  position: fixed;
  height: 100vh;
  width: 100%;
  top: 0;
  left: 0;
  background: #0d3b66;
  color: #fff;
  font-family: "Roboto", sans-serif;
  text-align: center;
}

.main-menu.active,
.end-screen.active {
  display: grid;
  place-items: center;
}

.main-menu {
  cursor: pointer;
}

.container {
  max-width: 700px;
  padding: 0 32px;
}

.main-menu h1 {
  font-size: 70px;
  margin: 8px 0;
}

.container p {
  font-size: 20px;
  line-height: 2;
  font-weight: 800;
  margin: 0;
}

.end-screen h1 {
  font-size: 30px;
}

.reaction-time-text {
  font-size: 100px;
  font-weight: 900;
}

.end-screen .play-again-btn {
  border: none;
  background: #faf0ca;
  font-size: 20px;
  padding: 8px 32px;
  margin-top: 20px;
  text-transform: uppercase;
  font-weight: 900;
  letter-spacing: 4px;
  cursor: pointer;
}