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

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background-color: #f5f5f5;
  color: #333;
  line-height: 1.6;
  padding: 20px;
  min-height: 100vh;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 30px;
  padding-bottom: 20px;
  border-bottom: 2px solid #e0e0e0;
}

header h1 {
  color: #2c3e50;
  font-size: 2.2rem;
}

header h1 i {
  margin-right: 10px;
  color: #3498db;
}

.btn-primary {
  background-color: #3498db;
  color: white;
  border: none;
  padding: 12px 24px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 600;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 8px;
}

.btn-primary:hover {
  background-color: #2980b9;
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.btn-secondary {
  background-color: #95a5a6;
  color: white;
  border: none;
  padding: 10px 20px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: all 0.3s ease;
}

.btn-secondary:hover {
  background-color: #7f8c8d;
}

.btn-danger {
  background-color: #e74c3c;
  color: white;
  border: none;
  padding: 8px 16px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: all 0.3s ease;
}

.btn-danger:hover {
  background-color: #c0392b;
}

.btn-success {
  background-color: #2ecc71;
  color: white;
  border: none;
  padding: 8px 16px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: all 0.3s ease;
}

.btn-success:hover {
  background-color: #27ae60;
}

.books-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 25px;
  margin-top: 20px;
}

.empty-library {
  grid-column: 1 / -1;
  text-align: center;
  padding: 60px 20px;
  color: #7f8c8d;
}

.empty-library i {
  font-size: 4rem;
  margin-bottom: 20px;
  color: #bdc3c7;
}

.empty-library h3 {
  font-size: 1.8rem;
  margin-bottom: 10px;
}

.empty-library p {
  font-size: 1.1rem;
  max-width: 500px;
  margin: 0 auto;
}

.book-card {
  background-color: white;
  border-radius: 10px;
  padding: 25px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
  transition: all 0.3s ease;
  display: flex;
  flex-direction: column;
  border-left: 5px solid #3498db;
}

.book-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
}

.book-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 15px;
}

.book-title {
  font-size: 1.4rem;
  color: #2c3e50;
  margin-bottom: 5px;
  flex: 1;
}

.book-author {
  color: #7f8c8d;
  font-style: italic;
  margin-bottom: 15px;
}

.book-details {
  margin-bottom: 20px;
  flex: 1;
}

.book-detail {
  display: flex;
  margin-bottom: 8px;
}

.book-detail-label {
  font-weight: 600;
  min-width: 100px;
  color: #34495e;
}

.book-detail-value {
  color: #2c3e50;
}

.book-status {
  display: inline-block;
  padding: 5px 12px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 20px;
  align-self: flex-start;
}

.status-read {
  background-color: #d5f4e6;
  color: #27ae60;
}

.status-unread {
  background-color: #fdebd0;
  color: #e67e22;
}

.book-actions {
  display: flex;
  gap: 10px;
  margin-top: auto;
}

/* Modal Styles */
#book-form-modal {
  border: none;
  border-radius: 12px;
  padding: 0;
  width: 90%;
  max-width: 500px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

#book-form-modal::backdrop {
  background-color: rgba(0, 0, 0, 0.5);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 25px;
  background-color: #3498db;
  color: white;
  border-radius: 12px 12px 0 0;
}

.modal-header h2 {
  font-size: 1.5rem;
}

.close-btn {
  background: none;
  border: none;
  color: white;
  font-size: 2rem;
  cursor: pointer;
  line-height: 1;
  padding: 0;
  width: 30px;
  height: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.close-btn:hover {
  opacity: 0.8;
}

#book-form {
  padding: 25px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 600;
  color: #2c3e50;
}

.form-group input[type="text"],
.form-group input[type="number"] {
  width: 100%;
  padding: 12px 15px;
  border: 2px solid #ddd;
  border-radius: 6px;
  font-size: 1rem;
  transition: border-color 0.3s ease;
}

.form-group input[type="text"]:focus,
.form-group input[type="number"]:focus {
  border-color: #3498db;
  outline: none;
}

.checkbox-group label {
  display: flex;
  align-items: center;
  font-weight: normal;
  cursor: pointer;
}

.checkbox-group input[type="checkbox"] {
  margin-right: 10px;
  width: 18px;
  height: 18px;
  cursor: pointer;
}

.form-buttons {
  display: flex;
  justify-content: flex-end;
  gap: 15px;
  margin-top: 30px;
}

/* Responsive Design */
@media (max-width: 768px) {
  header {
    flex-direction: column;
    gap: 15px;
    align-items: flex-start;
  }

  .books-container {
    grid-template-columns: 1fr;
  }

  .book-actions {
    flex-direction: column;
  }

  .btn-primary,
  .btn-secondary,
  .btn-danger,
  .btn-success {
    width: 100%;
    justify-content: center;
  }
}