* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

html, body {
  height: 100%;
  background-color: #f5f5f5;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  overflow: hidden;
}

.layout {
  display: flex;
  justify-content: center;
  height: 100vh;
  width: 100%;
}

.column {
  flex: 1;
  max-width: 500px;
  min-width: 0;
  height: 100vh;
}

.container {
  height: 100vh;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  overflow-x: hidden;
  padding: 16px;
  background-color: #f5f5f5;
}

.container.no-scroll {
  overflow: hidden;
}

.word-card {
  position: relative;
  background-color: #fff;
  border-radius: 12px;
  padding: 20px;
  margin-bottom: 16px;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.04);
  overflow: visible;
  will-change: transform;
  user-select: none;
  -webkit-user-select: none;
  touch-action: pan-y;
}

.word-card:active {
  background-color: #f9f9f9;
}

.word-card.card-transition {
  transition: transform 0.35s cubic-bezier(0.22, 1, 0.36, 1);
}

.word-card.card-fill-up {
  transition: transform 0.3s cubic-bezier(0.22, 1, 0.36, 1);
}

.word-card.wordbook-enter {
  animation: wordbookSlideIn 0.3s ease-out;
}

@keyframes wordbookSlideIn {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.word-header {
  margin-bottom: 12px;
}

.word-text {
  font-size: 24px;
  font-weight: 700;
  color: #1a1a1a;
  display: block;
  margin-bottom: 6px;
}

.word-phonetic {
  display: inline-block;
}

.phonetic-text {
  font-size: 14px;
  color: #666;
}

.word-meaning {
  border-top: 1px solid #f0f0f0;
  padding-top: 12px;
}

.meaning-item {
  display: flex;
  align-items: flex-start;
  margin-bottom: 8px;
}

.meaning-item:last-child {
  margin-bottom: 0;
}

.pos-tag {
  flex-shrink: 0;
  font-size: 12px;
  color: #0052d9;
  background-color: #e8f0fe;
  padding: 3px 8px;
  border-radius: 4px;
  margin-right: 8px;
  line-height: 1.4;
}

.meaning-text {
  flex: 1;
  font-size: 15px;
  color: #333;
  line-height: 1.6;
}

.loading-tip {
  text-align: center;
  padding: 16px;
  color: #999;
  font-size: 13px;
}