/* 기본 글자 크기 증가 */
body {
  font-size: 16px;
  line-height: 1.6;
  font-family: sans-serif;
  padding: 10px;
}

/* 카드 스타일 */
.card-container {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
}

.card {
  width: 280px;
  min-height: 160px;
  border: 1px solid #ccc;
  border-radius: 10px;
  padding: 15px;
  font-size: 18px;
  position: relative;
  background-color: #f9f9f9;
  perspective: 1000px;
  cursor: pointer;
}

.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform 0.6s;
}

/*
.card:hover .card-inner {
  transform: rotateY(180deg);
}
*/

.card.flipped .card-inner {
  transform: rotateY(180deg);
}

/*
.card-front, .card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  background: #f0f0f0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  border: 1px solid #ccc;
  border-radius: 12px;
  backface-visibility: hidden;
}
*/

.card-front, .card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  padding: 10px;
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
}

/*
.card-back {
  background: #d0e8ff;
  transform: rotateY(180deg);
}
*/

.card-front {
  background-color: #ffffff;
}

.card-back {
  transform: rotateY(180deg);
  background-color: #f1f1f1;
}

/* 리스트 항목 */
li {
  margin-bottom: 12px;
  font-size: 18px;
}

/* 암기 체크박스 라벨 */
.check-label {
  font-size: 16px;
  display: block;
  margin-top: 8px;
}

/* 암기된 단어 스타일 */
.memorized {
  opacity: 0.5;
  color: #777;
}

/* 반응형 대응: 모바일 */
@media screen and (max-width: 600px) {
  body {
    font-size: 18px;
  }

  .card {
    width: 90%;
    font-size: 20px;
  }

  li {
    font-size: 20px;
  }

  label {
    font-size: 18px;
  }
}

/* 퀴즈 카드 */
.quiz-card {
  text-align: center;
  font-size: 24px;
  margin-top: 20px;
}

.quiz-question {
  font-size: 32px;
  font-weight: bold;
  margin: 20px 0;
}

.quiz-answer {
  margin: 20px 0;
  font-size: 28px;
  font-weight: bold;
  color: #007bff;
}

.quiz-controls {
  margin-top: 20px;
}

.quiz-controls button {
  font-size: 18px;
  padding: 10px 18px;
  margin: 0 8px;
}

.file-item {
  cursor: pointer;
  text-decoration: underline; /* 밑줄 표시 */
  //margin: 5px 0;
  color: #007bff;
}

.file-item.selected {
  font-weight: bold; /* 굵게 */
  color: #000; /* 선택된 항목은 색 다르게 */
}

.file-item:hover {
  text-decoration: none; /* 선택적으로 hover 시 밑줄 제거 */
}

#clearMemorizedBtn {
  margin-left: 10px;
  padding: 4px 8px;
  font-size: 0.9rem;
  cursor: pointer;
}