#number-guess,
#result,
#history {
  max-width: 400px;
  margin: 0 auto;
}

#history {
  margin-top: 16px;
}
nav {
  border-radius: 13px;
}
.banner {
  color: #ffd23f;
  font-size: 90px;
  font-family: sans-serif;
}

.navbar-brand {
  margin-left: 25%;
}
main {
  margin-top: 24px;
}

html {
  height: 100%;
}

body {
  margin: 0;
}

.bg {
  animation: slide 3s ease-in-out infinite alternate;
  background-image: linear-gradient(-60deg, #6c3 50%, #09f 50%);
  bottom: 0;
  left: -50%;
  opacity: 0.5;
  position: fixed;
  right: -50%;
  top: 0;
  z-index: -1;
}

.bg2 {
  animation-direction: alternate-reverse;
  animation-duration: 4s;
}

.bg3 {
  animation-duration: 5s;
}

.content {
  background-color: rgba(255, 255, 255, 0.8);
  border-radius: 0.25em;
  box-shadow: 0 0 0.25em rgba(0, 0, 0, 0.25);
  box-sizing: border-box;
  left: 50%;
  padding: 10vmin;
  position: fixed;
  text-align: center;
  top: 50%;
  transform: translate(-50%, -50%);
  width: 700px;
  height: 717px;
  overflow: hidden;
  margin-bottom: 0px;
  border-radius: 32px;
  border: green 3px solid;
}

@keyframes slide {
  0% {
    transform: translateX(-25%);
  }
  100% {
    transform: translateX(25%);
  }
}