* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #000;
}

#app {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

#start-btn {
  font-family: Monaco, "SF Mono", "Menlo", "Consolas", monospace;
  font-size: 14px;
  padding: 8px 24px;
  background: #c0c0c0;
  color: #000;
  border: none;
  outline: none;
  cursor: pointer;

  /* Windows 95 3D button effect */
  box-shadow:
    inset -1px -1px 0 0 #000,
    inset 1px 1px 0 0 #fff,
    inset -2px -2px 0 0 #808080,
    inset 2px 2px 0 0 #dfdfdf;
}

#start-btn:active {
  box-shadow:
    inset 1px 1px 0 0 #000,
    inset -1px -1px 0 0 #fff,
    inset 2px 2px 0 0 #808080,
    inset -2px -2px 0 0 #dfdfdf;
  padding: 9px 23px 7px 25px;
}

#start-btn.hidden {
  display: none;
}

#display {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: none;
  align-items: center;
  justify-content: center;
  background: #000;
}

#display.active {
  display: flex;
}

#display img,
#display video {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
}