/* ==========================================================
   BookShelf — Base styles
   ========================================================== */

:root {
  --bg: #f7f6f3;
  --text: #1a1a1a;
  --text-muted: #5f5f5f;
  --card-bg: #ffffff;
  --card-border: #e5e3dd;
  --accent: #d97706;
  --accent-hover: #b45309;
  --header-bg: #ffffff;
  --shadow: 0 2px 8px rgba(0,0,0,0.06);
  --shadow-hover: 0 8px 24px rgba(0,0,0,0.12);
  --radius: 14px;
  --transition: 0.25s ease;
}

[data-theme="dark"] {
  --bg: #111214;
  --text: #f2f2f2;
  --text-muted: #a3a3a3;
  --card-bg: #1b1c1f;
  --card-border: #2b2c30;
  --accent: #f5b942;
  --accent-hover: #ffcf6b;
  --header-bg: #17181b;
  --shadow: 0 2px 8px rgba(0,0,0,0.4);
  --shadow-hover: 0 10px 28px rgba(0,0,0,0.55);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Segoe UI', Roboto, system-ui, sans-serif;
  transition: background var(--transition), color var(--transition);
  line-height: 1.5;
}

a { color: inherit; text-decoration: none; }

/* ===== Header ===== */
.site-header {
  background: var(--header-bg);
  border-bottom: 1px solid var(--card-border);
  position: sticky;
  top: 0;
  z-index: 50;
  transition: background var(--transition), border-color var(--transition);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.logo {
  font-size: 1.4rem;
  font-weight: 700;
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.search-wrap {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

#searchInput, #categoryFilter {
  padding: 9px 12px;
  border-radius: 8px;
  border: 1px solid var(--card-border);
  background: var(--card-bg);
  color: var(--text);
  font-size: 0.95rem;
  outline: none;
  transition: border-color var(--transition);
}

#searchInput:focus, #categoryFilter:focus {
  border-color: var(--accent);
}

.theme-toggle {
  border: 1px solid var(--card-border);
  background: var(--card-bg);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1.1rem;
  transition: transform var(--transition), border-color var(--transition);
}

.theme-toggle:hover {
  transform: scale(1.08);
  border-color: var(--accent);
}

.theme-toggle.spin {
  animation: spinIcon 0.4s ease;
}

@keyframes spinIcon {
  from { transform: rotate(0deg) scale(1); }
  50% { transform: rotate(180deg) scale(1.15); }
  to { transform: rotate(360deg) scale(1); }
}

.icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: inline; }

/* ===== Hero ===== */
.hero {
  max-width: 1200px;
  margin: 0 auto;
  padding: 40px 20px 10px;
  text-align: center;
}

.hero h1 {
  font-size: 2rem;
  margin-bottom: 6px;
}

.hero p {
  color: var(--text-muted);
  margin-top: 0;
}

/* ===== Books grid ===== */
.books-grid {
  max-width: 1200px;
  margin: 0 auto;
  padding: 30px 20px 60px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 24px;
}

.book-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  overflow: hidden;
  cursor: pointer;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.5s ease,
              transform 0.4s cubic-bezier(0.22, 1, 0.36, 1),
              box-shadow 0.3s cubic-bezier(0.22, 1, 0.36, 1);
}

.book-card.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.book-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.book-cover {
  width: 100%;
  aspect-ratio: 2 / 3;
  object-fit: cover;
  background: var(--card-border);
}

.book-info {
  padding: 12px 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
}

.book-title {
  font-size: 1rem;
  font-weight: 600;
  margin: 0;
}

.book-author {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin: 0;
}

.book-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: auto;
  padding-top: 8px;
}

.book-category {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  background: var(--accent);
  color: #1a1a1a;
  padding: 3px 8px;
  border-radius: 999px;
  font-weight: 600;
}

.book-year {
  font-size: 0.82rem;
  color: var(--text-muted);
}

.no-results {
  text-align: center;
  color: var(--text-muted);
  padding: 40px 20px;
}

body.modal-open {
  overflow: hidden;
}

/* ===== Modal ===== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 20px;
  opacity: 0;
  transition: opacity 0.25s ease;
}

.modal-overlay[hidden] { display: none; }

.modal-overlay.is-open {
  opacity: 1;
}

.modal {
  background: var(--card-bg);
  border-radius: var(--radius);
  max-width: 640px;
  width: 100%;
  max-height: 85vh;
  overflow-y: auto;
  position: relative;
  padding: 30px;
  box-shadow: var(--shadow-hover);
  transform: scale(0.94) translateY(10px);
  transition: transform 0.25s cubic-bezier(0.22, 1, 0.36, 1);
}

.modal-overlay.is-open .modal {
  transform: scale(1) translateY(0);
}

.modal-close {
  position: absolute;
  top: 14px;
  right: 16px;
  background: none;
  border: none;
  font-size: 1.6rem;
  cursor: pointer;
  color: var(--text-muted);
  line-height: 1;
}

.modal-close:hover { color: var(--text); }

.modal-body {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}

.modal-cover {
  width: 160px;
  flex-shrink: 0;
  border-radius: 8px;
  box-shadow: var(--shadow);
  aspect-ratio: 2 / 3;
  object-fit: cover;
}

.modal-details {
  flex: 1;
  min-width: 200px;
}

.modal-details h2 {
  margin: 0 0 6px;
  font-size: 1.4rem;
}

.modal-details .modal-author {
  color: var(--text-muted);
  margin: 0 0 12px;
}

.modal-details .modal-meta-row {
  display: flex;
  gap: 10px;
  align-items: center;
  margin-bottom: 16px;
}

.modal-details .modal-description {
  line-height: 1.6;
  color: var(--text);
}

@media (max-width: 480px) {
  .modal-body { flex-direction: column; }
  .modal-cover { width: 120px; }
}

/* ===== Request a book ===== */
.request-section {
  max-width: 640px;
  margin: 0 auto;
  padding: 40px 20px 60px;
  text-align: center;
}

.request-form {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 20px;
  text-align: left;
}

.request-form input,
.request-form textarea {
  padding: 11px 14px;
  border-radius: 8px;
  border: 1px solid var(--card-border);
  background: var(--card-bg);
  color: var(--text);
  font-family: inherit;
  font-size: 0.95rem;
  outline: none;
  transition: border-color var(--transition);
}

.request-form input:focus,
.request-form textarea:focus {
  border-color: var(--accent);
}

.request-form button {
  background: var(--accent);
  color: #1a1a1a;
  border: none;
  padding: 12px;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition);
}

.request-form button:hover {
  background: var(--accent-hover);
}

.form-success {
  color: var(--accent);
  font-weight: 600;
  margin-top: 14px;
}

.form-error {
  color: #d64545;
  font-weight: 600;
  margin-top: 14px;
}

.request-form button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* ===== Footer ===== */
.site-footer {
  text-align: center;
  padding: 24px 20px;
  color: var(--text-muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--card-border);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .header-inner { flex-direction: column; align-items: stretch; }
  .header-controls { justify-content: space-between; }
  .search-wrap { flex: 1; }
  #searchInput { flex: 1; }
  .hero h1 { font-size: 1.6rem; }
}

@media (max-width: 480px) {
  .books-grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 16px; }
  .modal { padding: 22px; }
}

/* ===== Reduced motion ===== */
@media (prefers-reduced-motion: reduce) {
  .book-card,
  .theme-toggle,
  .theme-toggle.spin,
  .modal,
  .modal-overlay {
    animation: none !important;
    transition: none !important;
  }

  .book-card {
    opacity: 1 !important;
    transform: none !important;
  }
}