:root {
  --bg-color: #fcfbf7;
  --text-color: #333333;
  --accent-color: #7a8a9e;
  --gold-color: #c5a059;
  --card-shadow: 0 10px 25px rgba(0, 0, 0, 0.08);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: 'Shippori Mincho', serif, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding: 20px;
}

.container {
  max-width: 480px;
  width: 100%;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.header {
  margin-bottom: 24px;
}

.sub-title {
  font-size: 0.95rem;
  letter-spacing: 0.1em;
  color: var(--accent-color);
  margin-bottom: 6px;
}

.main-title {
  font-size: 1.8rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  margin-bottom: 8px;
}

.instruction {
  font-size: 0.85rem;
  color: #666;
  letter-spacing: 0.05em;
}

/* カードの立体設定 */
.card-container {
  width: 260px;
  height: 460px;
  perspective: 1000px;
  cursor: pointer;
  margin-bottom: 24px;
}

.card {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
  border-radius: 12px;
  box-shadow: var(--card-shadow);
}

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

.card-face {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 12px;
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
}

/* 表面 */
.card-front img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

/* 裏面 */
.card-back {
  background-color: #ffffff;
  transform: rotateY(180deg);
  border: 1px solid #eae6df;
  padding: 28px 20px;
}

.card-content {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  height: 100%;
  width: 100%;
}

.quote {
  font-size: 1.08rem;
  line-height: 1.8;
  text-align: left;
  color: #2c2c2c;
  word-break: break-all;
  margin-top: 10px;
}

.source {
  font-size: 0.7rem;
  color: #888;
  text-align: center;
  margin-bottom: 12px;
}

.note-btn {
  display: inline-block;
  padding: 10px 16px;
  background-color: transparent;
  border: 1px solid var(--gold-color);
  color: var(--gold-color);
  text-decoration: none;
  font-size: 0.85rem;
  border-radius: 20px;
  transition: all 0.3s ease;
  letter-spacing: 0.05em;
}

.note-btn:hover {
  background-color: var(--gold-color);
  color: #ffffff;
}

.note-btn.disabled {
  border-color: #ccc;
  color: #999;
  pointer-events: none;
}

.reset-btn {
  background: none;
  border: none;
  color: var(--accent-color);
  font-family: inherit;
  font-size: 0.9rem;
  cursor: pointer;
  padding: 8px 16px;
  border-bottom: 1px solid var(--accent-color);
  transition: opacity 0.3s;
}

.reset-btn:hover {
  opacity: 0.7;
}