* {
  box-sizing: border-box;
  color: yellow;
}

body {
  background-color: black;
}

.banner {
  background: linear-gradient(135deg, rgb(200, 0, 0) 30%, rgb(2, 2, 200) 75%);
  border: 2px solid yellow;
  text-align: center;
  width: 100%;
  padding: 10px;
}

.banner h1 {
  font-size: 50px;
  padding: 0;
  margin: 5px;
}

.banner h3 {
  font-size: 25px;
  padding: 0;
  margin: 5px;
}

.nav-bar a {
  display: inline-block;
  border: 2px solid yellow;
  font-size: 18px;
  font-weight: bold;
  text-decoration: none;
  text-align: center;
  width: 33%;
  height: 25px;
  margin-top: 10px;
  margin-bottom: 10px;
  cursor: pointer;
}