body {
  margin: 0;
  color: gainsboro;
  background-color: black;
}

header {
  position: absolute;  top: 0; /* stay on top of 3D canvas */
  width: 100%;
  text-align: center;
}
header>div {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  padding: 0 1em;
  background-color: rgba(0,0,0, 0.75);
}
header h1 {
  margin: 0 0 10px 0;
  text-shadow: 0 0 15px #FFF, 0 0 20px #49ff18, 0 0 30px #49FF18, 0 0 40px #49FF18, 0 0 55px #49FF18, 0 0 75px #49ff18;
}
header #controls {
  display: inline-flex;
  justify-content: center;
  align-items: center;
}
header #optRadio {
  margin-right: 1em;
}
header #infoBtn {
  align-self: flex-end;
  cursor: pointer;
  margin-bottom: 0.5em;
}

button.bigRed {
  margin: 1em;
  width: 40px;  height: 40px;
  background: radial-gradient(#b00, #c00);
  font-weight: bold;
  cursor: pointer;
  border-width: 0;
  border-radius: 50%;
  box-shadow: 0 0 0 5px #900, /* bevel */
    -1px -1px 0 5px rgb(225, 0, 0), /* bevel highlight */
    4px 5px 5px rgba(0,0,0,0.5), /* bevel shadow */
    inset -10px -15px 45px rgba(255, 255, 255, .25), /* button inner highlight */
    inset 0 0 0 2px rgb(250, 55, 55), /* button outer edge */
    inset 2px 3px 0 0 rgba(255, 255, 255, 0.8), /* top-left highlight */
    inset -2px -3px 0 0 rgba(255, 255, 255, 0.8); /* bottom-right highlight */
}
button.bigRed:focus { outline:none; }
button.bigRed:active, button.bigRed.pressed {
  background: radial-gradient(#700, #900);
  box-shadow: 0 0 0 5px #900,
    inset -10px -15px 45px rgba(255, 185, 185, .25),
    inset 1px 1px 4px 1px rgba(0, 0, 0, .85),
    inset -1px -1px 0 0 rgba(250, 100, 100, .75),
    -1px -1px 0 5px rgb(225, 0, 0),
    4px 5px 5px rgba(0,0,0,0.5);
}


#info {
  position: absolute;  top: 130px; /* stay on top of 3D canvas */
  width: 100%;
  user-select: none;
  pointer-events: none; /* ignore clicks so they go to renderer */
}
#info>div {
  margin: 0 auto;
  width: 350px;
  padding: 1em;
  background-color: rgba(0,0,0, 0.75);
}
#infoClose {
  float: right;
  pointer-events: auto; /* stop ignoring clicks */
  font-size: 14pt;
  color: white;
  background: hsl(210, 100%, 20%);
  border:  1px solid midnightblue;
  border-radius: 50%;
  cursor: pointer;
}