.box.box--100vw 
  .box__text
    p #[b F]ull width
.box.box--100p
  .box__text
    p Centered #[b C]olumn
.box.box--divide.box--divide-left 
  .box__text
    p #[b L]eft #[b O]ffset
.box.box--divide.box--divide-right 
  .box__text
    p #[b R]ight #[b O]ffset
.legend
  .legend__row
    p LO = (F - C) / -2
    p RO = (F - C) / -2
  .legend__row
    p LO - Left Offset
    p RO - Right Offset
    p F - Full-width (100wv)
    p C - Content (100%)

:root {
  --width-100vw: 100vw;
  --width-100p: 60vw;
}

body {
  min-height: 100vh;
  padding: 0;
  margin: 0;
  position: relative;
}

.box {
  will-change: true;
  position: absolute;
  top: 0;
  bottom: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  margin-left: auto;
  margin-right: auto;
  opacity: 0;
  animation-fill-mode: forwards;
  animation-duration: 9s;
  animation-iteration-count: infinite;
}

.box--100vw {
  background-color: #4158D0;
  backdrop-filter: rotate-hue(10%);
  width: var(--width-100vw);
  left: 50%;
  transform: translateX(-50%);
  animation-name: revealvw;
}

.box--100p {
  background-color: #C850C0;
  backdrop-filter: rotate-hue(20%);
  width: var(--width-100p);
  left: 50%;
  transform: translateX(-50%);
  animation-name: revealp;
}

.box--divide {
  background-color: #FFCC70;
  backdrop-filter: rotate-hue(30%);
  width: calc((var(--width-100vw) - var(--width-100p)) / 2);
}

.box--divide-left {
  left: 0;
  animation-name: reveall;
}

.box--divide-right {
  right: 0;
  animation-name: revealr;
}

.box__text {
  text-align: center;
  
  @media screen and (max-width: 600px) {
    writing-mode: vertical-rl;
    transform: rotate(180deg);
  }
}

p {
  margin: 0;
  line-height: 2;
}

.legend {
  background-color: #FFFB7D;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0; 
}

.legend__row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  
  p {
    padding-left: .5em;
    padding-right: .5em;
  }
}

@keyframes revealvw {
  0% {
    opacity: 0;
  }
  5%,
  100% {
    opacity: 1;
  }
}

@keyframes revealp {
  0%,
  20% {
    opacity: 0;
  }
  25%,
  100% {
    opacity: 1;
  }
}

@keyframes reveall {
  0%,
  40% {
    opacity: 0;
  }
  45%,
  100% {
    opacity: 1;
  }
}

@keyframes revealr {
  0%,
  60% {
    opacity: 0;
  }
  65%,
  100% {
    opacity: 1;
  }
}