body {
  background: #2b2b2b;
  margin: 0;
  height: 100vh;             /* full viewport height */
  display: flex;
  justify-content: center;   /* horizontal centering */
  align-items: center;       /* vertical centering */
  color: #e0e0e0;
  font-family: sans-serif;
}

#main1 {
  text-align: center;
}

#main1 a.link {
  display: block;
  margin: 1px 0;
}

a.link {
  color: #d88933;
  text-decoration: none;
}

a.link:hover {
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 0 auto;
}