body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  line-height: 1.6;
  margin: 0;
  color: #222;
  background: #f9f9fc;
}
.container { max-width: 960px; margin: 0 auto; padding: 0 1rem; }

header {
  background: linear-gradient(90deg, #004b8d, #0074d9);
  color: #fff;
  padding: 1rem 0;
  text-align: center;
}
header h1 { margin: 0; font-size: 1.6rem; }
header h1 a { color: #fff; text-decoration: none; }
nav ul {
  list-style: none; padding: 0; margin: 0.5rem 0 0;
  display: flex; flex-wrap: wrap; gap: 1rem;
}
nav a { color: #fff; text-decoration: none; }
nav a:hover { text-decoration: underline; }

.breadcrumbs { font-size: 0.9em; margin: 1rem 0; color: #555; }
.breadcrumbs a { color: #004b8d; text-decoration: none; }

.content-text, .book-detail, .featured-book, .recent-books {
  background: #fff;
  margin: 1rem 0;
  padding: 1rem 1.5rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.content-text h2, .featured-book h2, .recent-books h2 { color: #004b8d; }

.book-card {
  display: flex; flex-wrap: wrap;
  align-items: flex-start; gap: 1rem;
  background: #f8f8ff;
  border: 1px solid #ddd;
  border-radius: 8px;
  padding: 1rem;
}
.book-card img {
  border-radius: 4px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  transition: transform 0.2s;
}
.book-card img:hover { transform: scale(1.04); }

.book-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
  gap: 0.8rem;
  margin-top: 0.5rem;
}
.book-thumb img {
  width: 100%; border-radius: 6px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.15);
  transition: transform 0.2s;
}
.book-thumb img:hover { transform: scale(1.05); }

.isbn-form {
  margin-top: 2rem;
  display: flex; flex-wrap: wrap; gap: 0.5rem; align-items: center;
}
.isbn-form input {
  flex: 1; min-width: 200px;
  padding: 0.5rem;
  border: 1px solid #ccc;
  border-radius: 4px;
}
.isbn-form button {
  background: #004b8d; color: #fff;
  border: none; border-radius: 4px;
  padding: 0.55rem 1rem; cursor: pointer;
}
.isbn-form button:hover { background: #003366; }

footer {
  text-align: center;
  font-size: 0.85em;
  color: #eee;
  background: #004b8d;
  padding: 1rem 0;
}
footer a { color: #fff; text-decoration: none; }
footer a:hover { text-decoration: underline; }

@media (max-width: 700px) {
  nav ul { flex-direction: column; gap: 0.4rem; }
  .book-card { flex-direction: column; align-items: center; text-align: center; }
  .book-card img { width: 60%; height: auto; }
  .isbn-form { flex-direction: column; align-items: stretch; }
}