* {
  box-sizing: border-box;
  font-family: sans-serif;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

body {
  margin: 0;
  background: #f8f8f8;
}

.retro-page {
  margin: 0 auto;
  max-width: 960px;
  padding: 20px 14px 40px;
}

h1 {
  border: 3px solid;
  border-color: green;
  text-align: center;
  background-color: rgb(224, 247, 228);
  color: rgb(34, 34, 34);
  width: min(680px, 90%);
  margin-left: auto;
  margin-right: auto;
  padding: 10px;
}

h2 {
  text-align: center;
  background-color: rgb(71, 61, 121);
  color: rgb(255, 255, 255);
  width: min(340px, 90%);
  margin-left: auto;
  margin-right: auto;
  padding: 10px;
}

h3 {
  text-align: center;
  background-color: rgb(120, 110, 174);
  color: rgb(255, 255, 255);
  width: min(300px, 90%);
  margin-left: auto;
  margin-right: auto;
  padding: 10px;
}

.box-container {
  border: 2px solid gray; 
  padding: 15px;          
  width: 50%;             
  margin: 10px auto 0;           
  background-color: #f9f9f9;
  width: min(680px, 90%);
}