:root {
  --video-opacity: 0.2;
  --fade-duration: 900ms;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  overflow: hidden;
  background: #fff;
  color: #000;
  font-family: ui-sans-serif, system-ui, -apple-system, "Helvetica Neue", Arial,
    sans-serif;
  -webkit-tap-highlight-color: transparent;
}

/* Full-screen loop sitting behind the logo. */
.backdrop {
  position: fixed;
  inset: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--fade-duration) ease;
}

.backdrop.is-visible {
  opacity: var(--video-opacity);
}

.stage {
  position: relative;
  z-index: 1;
  display: grid;
  place-items: center;
  min-height: 100%;
  min-height: 100svh;
  padding: 6vmin;
}

.logo {
  display: block;
  width: clamp(180px, 34vmin, 380px);
  padding: 0;
  border: 0;
  background: none;
  cursor: pointer;
  -webkit-user-select: none;
  user-select: none;
}

.logo img {
  display: block;
  width: 100%;
  height: auto;
}

.logo:focus {
  outline: none;
}

/* Contour ring, not a box: dilate the logo's alpha into an offset outline. */
.logo.is-keyboard-focus img {
  filter: url("#logo-focus-ring");
}

.filters {
  position: absolute;
  width: 0;
  height: 0;
  overflow: hidden;
}

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

@media (prefers-reduced-motion: reduce) {
  .backdrop {
    transition-duration: 1ms;
  }
}