html, body {
  height: 100%;
  margin: 0;
  padding: 0;
  background: #111;
  overflow: hidden; /* Prevents scrollbars */
  color: white;
}

body {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
}

.content {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100vw;
  height: 100vh;
}

#hero {
  display: block;
  box-sizing: border-box;
  border: 1.5em solid;
  max-width: calc(100vw - 3em);
  max-height: calc(100vh - 3em);
  width: auto;
  height: auto;
  background: #000;
}