:root{
  --intro-bg: #F5F5F5;
  --intro-fill: #FFFEEE;

  --t-intro-fill: 2400ms;
}

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

body.intro{
  background: var(--intro-bg);
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  overflow: hidden;
}

/* Stage */
.intro__stage{
  position: relative;
  height: 100%;
  width: 100%;
}

/* ------------------ */
/* LAYER 1 — CONTENT  */
/* ------------------ */

.intro__content{
  position: absolute;
  inset: 0;
  z-index: 1;

  display: grid;
  place-content: center;
  text-align: center;
  gap: 1.2rem;
}

.intro__title{
  font-size: 2.2rem;
  font-weight: 550;
  letter-spacing: 0.02em;
  margin: 0;
}

.intro__enter{
  border: none;
  background: transparent;
  padding: 0;
  cursor: pointer;
  display: inline-flex;
  justify-content: center;
  align-items: center;
  transition: transform 220ms ease;
}

.intro__enter img{
  width: 7rem;
  height: auto;
  display: block;
}

.intro__enter:hover{
  transform: scale(1.05);
}

.intro__enter:active{
  transform: scale(0.97);
}

.intro__enter:disabled{
  cursor: default;
}

/* ------------------ */
/* LAYER 2 — LIQUID   */
/* ------------------ */

.intro__liquid-layer{
  position: absolute;
  inset: 0;
  z-index: 2;

  pointer-events: none;

  opacity: 0;
  transition: opacity 200ms linear;
}

.intro.is-filling .intro__liquid-layer{
  opacity: 1;
}

#introLiquid{
  width: 100%;
  height: 100%;
  display: block;
}