/* Lyon Regular (best effort). If you have the actual font file, replace this with a real src:url(...) */
@font-face{
  font-family: "Lyon";
  src: local("Lyon Text Regular"), local("Lyon Regular"), local("Lyon");
  font-weight: 400;
  font-style: normal;
}

:root{
  /* safe zones so atoms never cover the 4 texts */
  --padTop: 90px;
  --padBottom: 90px;
  --padLeft: 150px;
  --padRight: 150px;
}

body{
  margin: 0;
  height: 100vh;
  overflow: hidden;
  font-family: "Lyon", Georgia, "Times New Roman", serif;
  background: var(--bg);
  color: var(--text);
  transition: background-color .25s ease, color .25s ease;
}

/* modes */
body.light{
  --bg: #ffffff;
  --text: #111111;
  --muted: #8a8a8a;
  --glow: rgba(0,0,0,.18);
}

body.dark{
  --bg: #000000;
  --text: #f2f2f2;
  --muted: #8a8a8a;
  --glow: rgba(255,255,255,.18);
}

/* layers */
#scene{
  position: fixed;
  inset: 0;
  z-index: 1;
}

#ui{
  position: fixed;
  inset: 0;
  z-index: 2;
  pointer-events: none; /* UI text doesn't block atoms; buttons re-enable below */
}

/* side texts */
.sideText{
  position: fixed;
  left: 0;
  top: 50%;
  transform-origin: center;
  letter-spacing: .2px;
  font-size: 28px;
  line-height: 1;
  opacity: .95;
  user-select: none;
  pointer-events: none;
}

.sideText.left{
  left: 24px;
  transform: translateY(-50%) rotate(-90deg);
}

.sideText.right{
  right: 24px;
  left: auto;
  transform: translateY(-50%) rotate(90deg);
}

/* mode buttons */
.modeBtn{
  position: fixed;
  left: 50%;
  transform: translateX(-50%);
  background: none;
  border: none;
  padding: 10px 14px;
  font: inherit;
  font-size: 30px;
  color: var(--text);
  cursor: pointer;
  pointer-events: auto; /* clickable */
  user-select: none;
}

.modeBtn.top{ top: 18px; }
.modeBtn.bottom{ bottom: 18px; }

.modeBtn.active{
  color: var(--muted);
}

/* atoms */
.atom{
  position: absolute;
  display: block;
  width: var(--size);
  height: var(--size);
  transform: translate3d(0,0,0);
  will-change: transform;
}

.atom { transition: transform 0.02s linear; }

.atom img{
  width: 100%;
  height: 100%;
  display: block;
  user-select: none;
  -webkit-user-drag: none;
  filter: none; /* no drop shadow */
}