html, body {
  height: 100%;
  margin: 0;
}

body {
  background: #000;
  overflow: hidden;
}

/* Background GIF fades in with first image */
.bg-gif {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  z-index: -2;
  user-select: none;
  pointer-events: none;

  opacity: 0;
  transition: opacity 3000ms linear;

  -webkit-user-drag: none;
}

.bg-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.35);
  z-index: -1;
  pointer-events: none;

  opacity: 0;
  transition: opacity 3000ms linear;
}

body.started .bg-gif,
body.started .bg-overlay {
  opacity: 1;
}

/* INTRO */
.intro {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  background: #000;
  z-index: 10;

  opacity: 1;
  transition: opacity 500ms ease;
  pointer-events: auto;
}

.intro.hidden {
  opacity: 0;
  pointer-events: none;
}

.intro.gone {
  display: none;
}

/* MAIN */
.app {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 24px;
  pointer-events: none;
}

body.started .app {
  pointer-events: auto;
}

/* Frame + WWW = one centered object */
.center-wrap {
  display: grid;
  place-items: center;
  gap: 14px;
}

/* Image box */
.frame {
  width: min(70vw, 520px);
  aspect-ratio: 3 / 4;
  border: 1px solid rgba(255, 255, 255, 0.22);
  box-shadow: 0 18px 60px rgba(0, 0, 0, 0.55);
  background: rgba(0, 0, 0, 0.25);
  overflow: hidden;
  position: relative;
}

/* Slides */
.slideshow {
  position: absolute;
  inset: 0;
}

.slide {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;

  opacity: 0;
  transition: opacity 3000ms linear;
  will-change: opacity;

  user-select: none;
  pointer-events: none;
  -webkit-user-drag: none;
}

.slide.is-active {
  opacity: 1;
}

/* PNG hover swap */
.img-btn {
  position: relative;
  border: 0;
  padding: 0;
  background: transparent;
  cursor: pointer;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}

.img-btn img {
  display: block;
  height: auto;
  user-select: none;
  -webkit-user-drag: none;
  pointer-events: none;
}

/* highlight fades in fast + smooth */
.img-btn .hover {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity 140ms ease-out;
}

.img-btn .base {
  transition: opacity 140ms ease-out;
}

.img-btn:hover .hover {
  opacity: 1;
}

.img-btn:hover .base {
  opacity: 0;
}

/* WWW button fades in with first image */
.www-btn {
  display: grid;
  place-items: center;

  width: fit-content;
  max-width: min(70vw, 520px);

  opacity: 0;
  transition: opacity 3000ms linear;
}

body.started .www-btn {
  opacity: 1;
}

.www-btn img {
  width: auto;
  max-width: min(70vw, 520px);
  height: auto;
}

/* Start button scale (responsive) */
.start-btn img {
  width: min(70vw, 520px);
  max-width: 520px;
}