* {
  box-sizing: border-box;
}

body {
  font-family: system-ui, sans-serif;
  margin: 0;
  background: #f5f5f5;
  color: #222;
}

.site-header {
  padding: 1rem 1.5rem;
  background: #1e3a5f;
  color: white;
}

.site-header h1 {
  margin: 0 0 0.25rem;
  font-size: 1.4rem;
}

.total-progress {
  margin: 0;
  opacity: 0.85;
  font-size: 0.9rem;
}

.main-nav {
  display: flex;
  gap: 1rem;
  margin: 0.25rem 0 0.5rem;
}

.main-nav a {
  color: white;
  text-decoration: none;
  font-size: 0.9rem;
  opacity: 0.85;
}

.main-nav a:hover {
  opacity: 1;
  text-decoration: underline;
}

#app {
  padding: 1.5rem;
  max-width: 900px;
  margin: 0 auto;
}

.lesson-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.75rem;
}

.lesson-card {
  background: white;
  border: 1px solid #ddd;
  border-radius: 8px;
  padding: 0.75rem 1rem;
  text-align: left;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.lesson-card:hover {
  border-color: #1e3a5f;
}

.lesson-card-main {
  background: none;
  border: none;
  padding: 0;
  text-align: left;
  cursor: pointer;
  font: inherit;
  color: inherit;
}

.lesson-card .lesson-title {
  font-weight: 600;
}

.lesson-card .lesson-progress {
  font-size: 0.85rem;
  color: #555;
}

.quiz-button {
  align-self: flex-start;
  padding: 0.3rem 0.7rem;
  font-size: 0.8rem;
  border-radius: 6px;
  border: 1px solid #1e3a5f;
  background: white;
  color: #1e3a5f;
  cursor: pointer;
}

.quiz-button:hover {
  background: #1e3a5f;
  color: white;
}

.error {
  color: #b00020;
}

.back-link {
  background: none;
  border: none;
  color: #1e3a5f;
  cursor: pointer;
  padding: 0;
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
}

.card-counter {
  font-size: 0.85rem;
  color: #555;
  margin-bottom: 0.5rem;
}

.flashcard {
  background: white;
  border: 1px solid #ddd;
  border-radius: 12px;
  padding: 2rem 1.5rem;
  min-height: 180px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  text-align: center;
}

.card-front .word {
  font-size: 1.6rem;
  font-weight: 700;
}

.card-front .ipa {
  color: #666;
  margin: 0.25rem 0 0.75rem;
}

.play-audio {
  border: 1px solid #1e3a5f;
  background: white;
  color: #1e3a5f;
  border-radius: 6px;
  padding: 0.35rem 0.75rem;
  cursor: pointer;
}

.card-back .example {
  font-style: italic;
  margin-top: 0.75rem;
}

.card-back .example-vi {
  color: #555;
}

.card-nav,
.card-grading {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.75rem;
}

.card-nav button,
.card-grading button {
  flex: 1;
  padding: 0.5rem;
  border-radius: 6px;
  border: 1px solid #ccc;
  background: white;
  cursor: pointer;
}

.card-grading button:first-child {
  border-color: #2e7d32;
  color: #2e7d32;
}

.card-grading button:last-child {
  border-color: #b00020;
  color: #b00020;
}

.grammar-title {
  font-size: 1.2rem;
  margin: 0 0 1rem;
}

.grammar-content {
  background: white;
  border: 1px solid #ddd;
  border-radius: 8px;
  padding: 1rem 1.5rem;
  line-height: 1.5;
  overflow-x: auto;
}

.grammar-content p {
  margin: 0.75rem 0;
}

.grammar-content table {
  width: 100% !important;
  border-collapse: collapse;
  margin: 1rem 0;
}

.grammar-content td,
.grammar-content th {
  border: 1px solid #ddd !important;
  padding: 0.5rem !important;
  width: auto !important;
}

.quiz-prompt {
  font-size: 1.3rem;
  font-weight: 600;
  margin: 1rem 0;
  text-align: center;
}

.quiz-choices {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.quiz-choice {
  padding: 0.75rem 1rem;
  border-radius: 8px;
  border: 1px solid #ccc;
  background: white;
  text-align: left;
  cursor: pointer;
}

.quiz-choice:disabled {
  cursor: default;
}

.quiz-choice.correct {
  border-color: #2e7d32;
  background: #e8f5e9;
  color: #2e7d32;
}

.quiz-choice.incorrect {
  border-color: #b00020;
  background: #fdecea;
  color: #b00020;
}

.quiz-next {
  margin-top: 1rem;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  border: 1px solid #1e3a5f;
  background: #1e3a5f;
  color: white;
  cursor: pointer;
}

.quiz-summary {
  font-size: 1.4rem;
  font-weight: 700;
  text-align: center;
  margin: 2rem 0 1rem;
}