/* CSS Variables for theming */
:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: #1a1a24;
  --bg-card-hover: #22222e;
  --text-primary: #e8e8ed;
  --text-secondary: #a0a0b0;
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --border-color: #2a2a3a;
  --shadow: rgba(0, 0, 0, 0.4);
  --overlay: rgba(0, 0, 0, 0.85);
}

/* Reset and base styles */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

/* Header */
.header {
  background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
  padding: 2rem 1rem;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
}

.header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  background: linear-gradient(135deg, var(--accent) 0%, #a78bfa 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header p {
  color: var(--text-secondary);
  font-size: 1.1rem;
}

/* Filter controls */
.filters {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
  padding: 1.5rem 1rem;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.filter-group {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.filter-group label {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.filter-group select,
.filter-group input {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.5rem 1rem;
  border-radius: 6px;
  font-size: 0.9rem;
  cursor: pointer;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.filter-group select:hover,
.filter-group input:hover {
  border-color: var(--accent);
}

.filter-group select:focus,
.filter-group input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

/* Main container */
.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

/* Book count display */
.book-count {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
}

/* Books grid */
.books-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 1.5rem;
}

@media (min-width: 640px) {
  .books-grid {
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  }
}

@media (min-width: 1024px) {
  .books-grid {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  }
}

/* Book card */
.book-card {
  background-color: var(--bg-card);
  border-radius: 12px;
  overflow: hidden;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s, background-color 0.2s;
  border: 1px solid var(--border-color);
}

.book-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 24px var(--shadow);
  background-color: var(--bg-card-hover);
}

.book-card:focus {
  outline: none;
  box-shadow: 0 0 0 3px var(--accent);
}

/* Cover image container */
.cover-container {
  position: relative;
  width: 100%;
  padding-top: 150%; /* 2:3 aspect ratio for book covers */
  background-color: var(--bg-secondary);
  overflow: hidden;
}

.cover-container img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: opacity 0.3s;
}

/* Placeholder for missing covers */
.cover-placeholder {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-card) 100%);
  padding: 1rem;
  text-align: center;
}

.cover-placeholder .book-icon {
  font-size: 3rem;
  margin-bottom: 0.5rem;
  opacity: 0.5;
}

.cover-placeholder .placeholder-title {
  font-size: 0.85rem;
  color: var(--text-secondary);
  word-break: break-word;
}

/* Loading spinner for images */
.cover-loading {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 32px;
  height: 32px;
  border: 3px solid var(--border-color);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to { transform: translate(-50%, -50%) rotate(360deg); }
}

/* Card info section */
.card-info {
  padding: 1rem;
}

.card-info h3 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
  color: var(--text-primary);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-info .author {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.card-info .meta {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.format-badge {
  display: inline-block;
  font-size: 0.7rem;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.format-badge.audiobook { background-color: #3730a3; color: #c7d2fe; }
.format-badge.ebook { background-color: #065f46; color: #a7f3d0; }
.format-badge.paperback { background-color: #7c2d12; color: #fed7aa; }

/* Modal overlay */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: var(--overlay);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s;
  padding: 1rem;
  overflow-y: auto;
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

/* Modal content */
.modal-content {
  background-color: var(--bg-secondary);
  border-radius: 16px;
  max-width: 800px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  position: relative;
  transform: scale(0.9);
  transition: transform 0.3s;
  border: 1px solid var(--border-color);
}

.modal-overlay.active .modal-content {
  transform: scale(1);
}

/* Close button */
.modal-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  width: 40px;
  height: 40px;
  border: none;
  background-color: var(--bg-card);
  color: var(--text-primary);
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color 0.2s;
  z-index: 10;
}

.modal-close:hover {
  background-color: var(--bg-card-hover);
}

/* Modal body layout */
.modal-body {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  padding: 1.5rem;
}

@media (min-width: 640px) {
  .modal-body {
    grid-template-columns: 250px 1fr;
    padding: 2rem;
  }
}

/* Modal cover image */
.modal-cover {
  position: relative;
  width: 100%;
  max-width: 250px;
  margin: 0 auto;
}

.modal-cover {
  position: relative;
}

.modal-cover img {
  width: 100%;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 8px 24px var(--shadow);
}

.modal-cover .cover-loading {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 48px;
  height: 48px;
  border: 4px solid var(--border-color);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  z-index: 1;
}

.modal-cover .cover-placeholder {
  position: relative;
  padding-top: 150%;
  border-radius: 8px;
}

/* Modal details */
.modal-details h2 {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.modal-details .author {
  font-size: 1.1rem;
  color: var(--accent);
  margin-bottom: 1rem;
}

.modal-meta {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.meta-item {
  display: flex;
  flex-direction: column;
}

.meta-item .label {
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.meta-item .value {
  font-size: 1rem;
  color: var(--text-primary);
}

/* Summary section */
.modal-summary h3 {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.modal-summary p {
  color: var(--text-primary);
  line-height: 1.7;
  margin-bottom: 1.5em;
}

.modal-summary p:last-of-type {
  margin-bottom: 0;
}

.modal-summary .loading {
  color: var(--text-secondary);
  font-style: italic;
}

.modal-summary .no-summary {
  color: var(--text-secondary);
  font-style: italic;
}

.modal-summary .summary-source {
  margin-top: 1rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
  font-style: italic;
}

/* Loading state for the grid */
.loading-message {
  text-align: center;
  padding: 4rem 2rem;
  color: var(--text-secondary);
}

.loading-message .spinner {
  width: 48px;
  height: 48px;
  border: 4px solid var(--border-color);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin: 0 auto 1rem;
}

/* Error state */
.error-message {
  text-align: center;
  padding: 4rem 2rem;
  color: #ef4444;
}

/* No results state */
.no-results {
  text-align: center;
  padding: 4rem 2rem;
  color: var(--text-secondary);
}

/* Footer */
.footer {
  text-align: center;
  padding: 2rem 1rem;
  color: var(--text-secondary);
  font-size: 0.85rem;
  border-top: 1px solid var(--border-color);
  margin-top: 2rem;
}

.footer a {
  color: var(--accent);
  text-decoration: none;
}

.footer a:hover {
  text-decoration: underline;
}