:root {
  color-scheme: dark;
}

* {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  min-height: 100%;
  margin: 0;
  background: #000;
}

body {
  overflow: hidden;
  font-family: Tahoma, Arial, sans-serif;
}

button {
  font: inherit;
}

.shutdown-screen {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  background: #000;
  isolation: isolate;
}

.shutdown-panel {
  display: grid;
  justify-items: center;
  gap: 30px;
  transform: translateY(-5vh);
  transition:
    opacity 90ms linear,
    visibility 90ms linear;
}

.shutdown-panel h1 {
  transform: translateY(-20px);
  margin: 0;
  color: #e8e8e8;
  font-size: clamp(24px, 3vw, 46px);
  font-weight: 400;
  letter-spacing: .035em;
  text-align: center;
  text-shadow: 0 0 18px rgba(255, 255, 255, .12);
}

.power-button {
  display: block;
  width: min(630px, 72vw);
  padding: 0;
  border: 0;
  background: transparent;
  cursor: pointer;
  transition: transform 90ms ease;
}

.switch-stack {
  position: relative;
  display: block;
  width: 100%;
}

.switch-stack img {
  display: block;
  width: 100%;
  height: auto;
  user-select: none;
  -webkit-user-drag: none;
  pointer-events: none;
}

.switch-base {
  filter: brightness(.75);
}

.switch-light {
  position: absolute;
  inset: 0;
  opacity: .8;
  transition: opacity 70ms linear;
}

/* Das Licht erlischt sofort beim Anklicken. */
.power-button.is-pressed .switch-light,
.shutdown-screen.is-off .switch-light {
  opacity: 0;
}

.power-button:hover .switch-light {
  opacity: 1;
  filter: brightness(1.35);
}

.power-button:focus-visible {
  outline: 3px solid #fff;
  outline-offset: 10px;
}

.power-button:active,
.power-button.is-pressed {
  transform: translateY(3px) scale(.992);
}

.crt-flash {
  position: absolute;
  inset: 0;
  z-index: 3;
  display: grid;
  place-items: center;
  pointer-events: none;
  opacity: 0;
}

.crt-line,
.crt-dot {
  position: absolute;
  display: block;
  background: #fff;
  opacity: 0;
}

.crt-line {
  width: min(88vw, 1450px);
  height: 4px;
  border-radius: 50%;
  box-shadow:
    0 0 5px #fff,
    0 0 14px rgba(255, 255, 255, .95),
    0 0 34px rgba(255, 255, 255, .6);
  transform-origin: center;
}

.crt-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  box-shadow:
    0 0 8px #fff,
    0 0 22px rgba(255, 255, 255, .9);
}

.shutdown-screen.is-shutting-down .shutdown-panel {
  opacity: 0;
  visibility: hidden;
}

.shutdown-screen.is-shutting-down .crt-flash {
  opacity: 1;
}

.shutdown-screen.is-shutting-down .crt-line {
  animation: crt-line-collapse 620ms cubic-bezier(.7, 0, .95, .45) forwards;
}

.shutdown-screen.is-shutting-down .crt-dot {
  animation: crt-dot-fade 620ms linear forwards;
}

@keyframes crt-line-collapse {
  0% {
    opacity: 0;
    transform: translateY(-3px) scaleX(.96) scaleY(7);
  }
  8% {
    opacity: 1;
    transform: translateY(2px) scaleX(1) scaleY(4);
  }
  18% {
    transform: translateY(-2px) scaleX(.97) scaleY(2.5);
  }
  31% {
    transform: translateY(1px) scaleX(.92) scaleY(1.6);
  }
  55% {
    opacity: 1;
    transform: translateY(0) scaleX(.56) scaleY(1);
  }
  78% {
    opacity: .95;
    transform: translateY(0) scaleX(.08) scaleY(.8);
  }
  91% {
    opacity: .75;
    transform: translateY(0) scaleX(.006) scaleY(.7);
  }
  100% {
    opacity: 0;
    transform: translateY(0) scaleX(0) scaleY(0);
  }
}

@keyframes crt-dot-fade {
  0%,
  78% {
    opacity: 0;
    transform: scale(1);
  }
  84% {
    opacity: 1;
    transform: scale(1.7);
  }
  94% {
    opacity: .75;
    transform: scale(.7);
  }
  100% {
    opacity: 0;
    transform: scale(0);
  }
}

.shutdown-screen.is-off {
  background: #000;
}

.shutdown-screen.is-off .shutdown-panel,
.shutdown-screen.is-off .crt-flash {
  display: none;
}

.return-hint {
  position: fixed;
  left: 50%;
  bottom: 18px;
  z-index: 5;
  margin: 0;
  color: rgba(255, 255, 255, .22);
  font-size: 13px;
  letter-spacing: .08em;
  opacity: 0;
  pointer-events: none;
  transform: translateX(-50%);
  transition: opacity .8s ease;
}

.return-hint.visible {
  opacity: 1;
}

@media (prefers-reduced-motion: reduce) {
  .shutdown-screen.is-shutting-down .crt-line,
  .shutdown-screen.is-shutting-down .crt-dot {
    animation-duration: 180ms;
  }
}