.interface {
  position: relative;
  background-color: grey;
}

.chooser {
  /* flex container */
  display: flex;
  align-items: center;
  justify-content: center;

  height: 100vh;
}

.answer {
  /*border: 3px solid red;*/

  /* flex container */
  display: flex;
  align-items: center;
  justify-content: center;

  /* flex item */
  flex: 2;

  height: 100%;

  color: white;
  font-size: 25px;
  font-weight: bold;
  line-height: 90%;
  text-align: center;
}

.exhibit {
  /*border: 3px solid goldenrod;*/

  /* flex container */
  display: flex;
  justify-content: center;
  height: 100%;

  /* flex item */
  flex: 8;
}

.exhibit img {
  width: 100%;
  object-fit: contain;
}

.indicator {
  /*border: 3px solid lightgreen;*/

  position: absolute;
  left: 0;
  top: 0;

  display: flex;
  align-items: center;
  justify-content: center;

  height: 100%;
  width: 100%;

  flex: 1 auto;

  font-size: 100px;
  font-weight: bold;
  color: gold;
}


.interface {
  position: relative;
  background-color: grey;
}

.chooser {
  /* flex container */
  display: flex;
  align-items: center;
  justify-content: center;

  height: 100vh;
}

.answer {
  /*border: 3px solid red;*/

  /* flex container */
  display: flex;
  align-items: center;
  justify-content: center;

  /* flex item */
  flex: 2;

  height: 100%;

  color: white;
  font-size: 25px;
  font-weight: bold;
  line-height: 90%;
  text-align: center;
}

.exhibit {
  /*border: 3px solid goldenrod;*/

  /* flex container */
  display: flex;
  justify-content: center;
  height: 100%;

  /* flex item */
  flex: 8;
}

.exhibit img {
  width: 100%;
  object-fit: contain;
}

.indicator {
  /*border: 3px solid lightgreen;*/

  position: absolute;
  left: 0;
  top: 0;

  display: flex;
  align-items: center;
  justify-content: center;

  height: 100%;
  width: 100%;

  flex: 1 auto;

  font-size: 100px;
  font-weight: bold;
  text-shadow: 0 0 10px black;
  color: white;
}


Make indicator text white with black shadow
Make indicator text white with black shadow

Make it easier to read over any background image.
