#avf-flashcards {
  max-width: 500px; margin: auto;
}
.avf-selector {
  text-align: center; margin-bottom: 15px;
}
.avf-selector label {
  margin-right: 5px; font-size: 1.1em;
}
#avf-timer {
  text-align: center; font-size: 1.2em; margin-bottom: 15px;
}
.avf-card-front,
.avf-card-back {
  font-family: 'Arial','Tahoma',sans-serif;
  font-size: 2em; text-align: center; margin: 0 auto 20px;
  width: 80%; border: 2px solid #ddd;
  padding: 20px; border-radius: 10px;
}
.avf-controls {
  text-align: center;
}
.avf-controls button {
  margin: 0 10px; padding: 10px 20px; font-size: 1em;
}
#avf-score {
  text-align: center; font-size: 1.2em; margin-top: 15px;
}