/* Basics */

*, *:before, *:after {
  box-sizing: inherit;
  margin: 0;
  padding: 0;
}

:root {
  box-sizing: border-box;
  line-height: 1.5;
  font-family: sans-serif;
  font-size: calc(2vw + 2em);
}

li {
  list-style: none;
}

code {
  font-family: Consolas, monaco, monospace;
  border: 2px dashed currentcolor;
}

h1 {
  font-size: 1.5rem;
}
h2 {
  font-size: 1rem;
}
h1, h2 {
  font-weight: bold;
}

/* Layout */
body {
  display: flex;
  flex-direction: column;
  padding: 0;
  margin: 0;
  background-color: black;
  color: white;
  overflow: hidden;
}

main {
  margin-top: 0;
  perspective: 100vmin;
  transform-style: preserve-3d;
  height: 100vh;
}

/* Components */
section {
  position: absolute;
  z-index: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 1em;
  overflow: hidden;
  text-align: center;
  background-color: black;
  transition: transform ease 0.5s, opacity ease 0.5s, visibility step-end 0.5s;
  transform-origin: 50% 50%;
}

[janus-timeline='past'] {
  transition: transform ease-in 0.5s, opacity ease-in 0.5s, visibility step-end 0.5s;
}

[janus-timeline='present'] {
  transition: transform ease-out 0.5s, opacity ease-out 0.5s, visibility step-start 0.5s;
}

@media not print {
  [janus-timeline='future'] {
    visibility: hidden;
  }
}

body.show-notes section [janus-timeline='future'] {
  visibility: visible;
  opacity: 0.25;
}

body.show-notes section[janus-timeline='future'] [janus-timeline='future'] {
  opacity: 1;
}

section[janus-timeline='past'] {
  transform: translate3d(0, 0, 0) scale(5);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  z-index: 2;
}

section[janus-timeline='present'] {
  transform: none;
  opacity: 1;
}

section[janus-timeline='future'] {
  transform: translate3d(0, -5vmin, 0) scale(0.8);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

img.cover {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 100%;
  object-fit: cover;
  z-index: -1;
}

body.show-notes section {
  transition: none;
}

body.show-notes section[janus-timeline='present'] + section[janus-timeline='future'] {
  transform: scale(0.25);
  transform-origin: bottom right;
  top: auto;
  left: auto;
  bottom: 0.4rem;
  right: 0.4rem;
  opacity: 0.75;
  visibility: visible;
  outline: 0.2rem solid white;
  z-index: 3;
}