* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: arial;
}
html {
  scroll-behavior: smooth;
  font-size: 62.5%;
}
body {
  width: 100vw;
  min-height: 100vh;
  background: grey;
  overflow-x: hidden;
}
#size {
  text-align: center;
  display: none;
  font-weight: bold;
  color:transparent;
  -webkit-text-stroke-color: white;
  -webkit-text-stroke-width: .5rem;
}
#show {
  text-align: center;
  margin-top: 1rem;
  font-size: 1.5rem;
  font-weight: bold;
}
.box {
  width: 20rem;
  height: 8rem;
  background: crimson;
  border: 0.2rem solid white;
  border-radius: 1rem;
  position: fixed;
  left: 50%;
  bottom: 3%;
  transform: translateX(-50%);
}

.box input {
  position: absolute;
  left: 50%;
  bottom: 10%;
  transform: translateX(-50%);
}