:root {
 --css-version: 4;
}
span.red {
 color: #ff0000;
}
span.redFb {
 color: #ff0000;
 font-size: 1.5em;
}
span.greenFb {
 color: #00ff00;
 font-size: 1.5em;
}

.fixChar {
  font-size: 1.5em;
}
.prompter {
  font-size: 1.5em;
  color: blue;
}
.stimChar {
  font-size: 10em;
}
.stimulus {
	display: grid;
 place-items: center;
 height: 100dvh;
}