* {
  box-sizing: border-box;
}

:root {
  --poster-background: url('/hero-desktop.png');
}

html,
body {
  margin: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #000;
  font-family: Arial, Helvetica, sans-serif;
}

.poster {
  position: fixed;
  inset: 0;
  background-color: #000;
  background-image: var(--poster-background);
  background-size: 100% 100%;
  background-position: center center;
  background-repeat: no-repeat;
}

@media (orientation: portrait) {
  :root {
    --poster-background: url('/hero-mobile.jpg');
  }

  .poster {
    background-size: 100% 100%;
    background-position: center top;
  }
}