/* ====== Base ====== */
body {
  font-family: 'Montserrat', Arial, sans-serif;
  background: #f9fafb;
  color: #2F2F2F;
  margin: 0;
  padding: 0;
}

header {
  background: #f0f4f9;
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  box-shadow: 0 2px 6px rgba(0,0,0,0.05);
}

header h1 {
  font-size: 1.8rem;
  margin: 0;
  color: #5B8DEF;
}

header nav {
  margin-left: auto;
}

header nav a {
  text-decoration: none;
  color: #5B8DEF;
  margin: 0 0.5rem;
  font-weight: 600;
}

header nav a:hover {
  color: #F6A800;
}

/* ====== Filter Bar ====== */
#filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 1rem 2rem;
}

.filter-btn, .clear-btn {
  background: #e6ecfa;
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 600;
}

.filter-btn.active {
  background: #5B8DEF;
  color: #fff;
}

.clear-btn {
  background: #F6A800;
  color: #fff;
}

/* ====== Book Grid ====== */
#book-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
  padding: 1.5rem 2rem;
}

.book-card {
  background: #fff;
  border: 1px solid #e3e9f3;
  border-radius: 10px;
  padding: 1rem;
  display: flex;
  flex-direction: column;
  box-shadow: 0 2px 6px rgba(0,0,0,0.04);
  transition: box-shadow 0.2s ease;
}

.book-card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.book-card img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: 8px;
  margin-bottom: 1rem;
}

.book-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin: 0.2rem 0;
  color: #2F2F2F;
}

.book-author {
  font-size: 0.95rem;
  color: #4F4F4F;
  margin-bottom: 0.5rem;
}

.book-rating {
  color: #F6A800;
  font-size: 1rem;
  margin-bottom: 0.5rem;
}

.book-genres {
  margin-bottom: 0.8rem;
}

.genre {
  display: inline-block;
  background: #e6ecfa;
  color: #5B8DEF;
  padding: 0.3em 0.6em;
  margin: 0.2em;
  border-radius: 8px;
  font-size: 0.8rem;
}

/* ====== Buttons ====== */
button, .buy-btn {
  background: #5B8DEF;
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 0.5rem 1rem;
  font-weight: 600;
  cursor: pointer;
  text-align: center;
  margin-top: auto;
  text-decoration: none;
  display: inline-block;
}

button:hover, .buy-btn:hover {
  background: #3d6fd1;
}

/* ====== Book Detail ====== */
#book-detail {
  padding: 2rem;
  max-width: 800px;
  margin: 0 auto;
}

.detail-section img {
  width: 100%;
  height: 300px;
  object-fit: cover;
  border-radius: 10px;
  margin-bottom: 1rem;
}

.detail-section h2 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  color: #2F2F2F;
}

.detail-section .book-author {
  font-size: 1rem;
  margin-bottom: 0.5rem;
}

.detail-section .book-summary {
  font-size: 1.05rem;
  margin: 1rem 0;
}

/* ====== Quizzes ====== */
.quiz-inline {
  margin: 1.5rem 0;
  padding: 1rem;
  background: #f0f4f9;
  border-radius: 8px;
}

.quiz-inline button {
  margin: 0.4em 0;
  background: #e6ecfa;
  border: none;
  padding: 0.5em;
  border-radius: 6px;
  cursor: pointer;
  width: 100%;
  text-align: left;
}

.quiz-inline button:hover {
  background: #5B8DEF;
  color: #fff;
}

.quiz-feedback.correct {
  color: #2e7d32;
  font-weight: bold;
}

.quiz-feedback.incorrect {
  color: #c62828;
  font-weight: bold;
}

/* ====== Footer ====== */
footer {
  padding: 1rem 2rem;
  text-align: center;
  font-size: 0.9rem;
  color: #4F4F4F;
  border-top: 1px solid #e3e9f3;
  margin-top: 2rem;
}