* { box-sizing: border-box; }
body {
  font-family: system-ui, sans-serif;
  margin: 0;
  padding: 0;
  background: #f5f6fa;
  color: #2c3e50;
}
h1 { margin: 0; }
#topAppBar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: #2c3e50;
  color: white;
  padding: 0.7rem 1rem;
}
#topAppBar button {
  background: none;
  border: none;
  color: white;
  font-size: 1.25rem;
  cursor: pointer;
  padding: 0.2rem 0.4rem;
  line-height: 1;
}
#appBarTitle { flex: 1; font-size: 1.1rem; text-align: left; }
.topbar-icons { display: flex; gap: 0.3rem; }
.page-content { padding: 0 1rem 5rem; }
.drawer-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  z-index: 30;
}
.drawer-overlay[hidden] { display: none; }
.side-drawer {
  position: fixed;
  top: 0; left: 0; bottom: 0;
  width: 260px;
  max-width: 80%;
  background: white;
  z-index: 31;
  box-shadow: 2px 0 8px rgba(0,0,0,0.2);
  display: flex;
  flex-direction: column;
  padding: 1rem;
  overflow-y: auto;
}
.side-drawer[hidden] { display: none; }
.drawer-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: bold;
  margin-bottom: 1rem;
}
.drawer-header button { background: none; border: none; font-size: 1.2rem; cursor: pointer; }
.drawer-section { margin-bottom: 0.5rem; }
.drawer-label { font-size: 0.78rem; color: #888; margin-bottom: 0.4rem; }
.drawer-item {
  display: block;
  width: 100%;
  text-align: left;
  padding: 0.65rem 0.3rem;
  border: none;
  background: none;
  border-top: 1px solid #eee;
  font-size: 0.95rem;
  color: #2c3e50;
  cursor: pointer;
}
.drawer-item:hover { background: #f5f6fa; }
.lang-dropdown { position: relative; display: inline-block; }
#langToggle {
  padding: 0.4rem 0.9rem;
  border: 1px solid #2c3e50;
  border-radius: 6px;
  background: white;
  color: #2c3e50;
  font-size: 0.9rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}
#langToggle:hover { background: #ecf0f1; }
#langToggle .arrow { font-size: 0.7rem; }
#langMenu {
  position: absolute;
  top: calc(100% + 4px);
  left: 0;
  background: white;
  border: 1px solid #ccc;
  border-radius: 6px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
  min-width: 140px;
  z-index: 32;
  overflow: hidden;
}
#langMenu[hidden] { display: none; }
.lang-option {
  display: block;
  width: 100%;
  padding: 0.5rem 0.9rem;
  border: none;
  background: white;
  color: #2c3e50;
  font-size: 0.9rem;
  text-align: left;
  cursor: pointer;
}
.lang-option:hover { background: #ecf0f1; }
.lang-option.active { font-weight: bold; background: #f5f6fa; }
#statsBar {
  display: flex;
  justify-content: center;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin: 1rem 0 0.75rem;
}
.stat-box {
  background: white;
  border-radius: 8px;
  padding: 0.6rem 1.1rem;
  min-width: 90px;
  text-align: center;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}
.stat-box .stat-number { display: block; font-size: 1.4rem; font-weight: bold; }
.stat-box .stat-label { font-size: 0.75rem; color: #666; }
#mainTabs {
  display: flex;
  max-width: 600px;
  margin: 0.5rem auto 0;
  gap: 0.4rem;
}
.tab-btn {
  flex: 1;
  padding: 0.6rem;
  border: none;
  background: #ecf0f1;
  color: #2c3e50;
  font-size: 0.95rem;
  cursor: pointer;
  border-radius: 6px 6px 0 0;
}
.tab-btn.active { background: white; font-weight: bold; box-shadow: 0 -2px 0 #2c3e50 inset; }
#pathRow {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  max-width: 600px;
  margin: 0 auto;
  padding: 0.55rem 0.25rem;
  font-size: 0.85rem;
  color: #666;
  border-bottom: 1px solid #ddd;
  background: white;
}
#breadcrumb { flex: 1; }
#filterBtn { background: none; border: none; font-size: 1.05rem; cursor: pointer; color: #2c3e50; }
.tab-view { max-width: 600px; margin: 0 auto; padding-top: 0.75rem; }
.tab-view[hidden] { display: none; }
#shelfAddRow { display: flex; gap: 0.5rem; margin-bottom: 0.75rem; }
#newShelfInput {
  flex: 1;
  padding: 0.5rem;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: 0.95rem;
}
#addShelfBtn {
  padding: 0.5rem 0.9rem;
  border: none;
  border-radius: 6px;
  background: #2c3e50;
  color: white;
  cursor: pointer;
}
#addShelfBtn:hover { background: #34495e; }
#shelfList { list-style: none; margin: 0; padding: 0; }
.shelf-row {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  background: white;
  border-radius: 8px;
  padding: 0.6rem 0.9rem;
  margin-bottom: 0.5rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  position: relative;
}
.shelf-thumb { font-size: 1.3rem; cursor: pointer; }
.shelf-main { flex: 1; min-width: 0; cursor: pointer; padding: 0.1rem 0.2rem; border-radius: 4px; }
.shelf-main:hover { background: #ecf0f1; }
.shelf-name { font-weight: 600; }
.shelf-count { display: block; font-size: 0.78rem; color: #888; }
.shelf-edit-input {
  width: 100%;
  padding: 0.3rem 0.4rem;
  border: 1px solid #2c3e50;
  border-radius: 4px;
  font-size: 0.95rem;
}
.shelf-menu-btn {
  background: none;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  color: #666;
  padding: 0.2rem 0.5rem;
}
.shelf-menu {
  position: absolute;
  right: 0.5rem;
  top: 2.6rem;
  background: white;
  border: 1px solid #ccc;
  border-radius: 6px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
  z-index: 5;
  min-width: 140px;
  overflow: hidden;
}
.shelf-menu[hidden] { display: none; }
.shelf-menu button {
  display: block;
  width: 100%;
  text-align: left;
  padding: 0.5rem 0.8rem;
  border: none;
  background: white;
  cursor: pointer;
  font-size: 0.9rem;
  color: #2c3e50;
}
.shelf-menu button:hover { background: #f5f6fa; }
#noShelvesMsg { color: #888; font-size: 0.9rem; }
#booksContent { display: flex; gap: 0.4rem; align-items: flex-start; }
#bookGroups { flex: 1; min-width: 0; }
#azIndex {
  display: flex;
  flex-direction: column;
  align-items: center;
  font-size: 0.7rem;
  color: #ccc;
  padding-top: 0.3rem;
  position: sticky;
  top: 3.2rem;
  user-select: none;
}
#azIndex button {
  background: none;
  border: none;
  padding: 3px 6px;
  cursor: default;
  color: inherit;
  font-size: 0.7rem;
}
#azIndex button.active-letter { color: #2c3e50; font-weight: bold; cursor: pointer; }
.group-heading {
  font-size: 0.8rem;
  font-weight: bold;
  color: #888;
  letter-spacing: 0.05em;
  margin: 1rem 0 0.4rem;
}
.book-row {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  background: white;
  border-radius: 8px;
  padding: 0.5rem 0.75rem;
  margin-bottom: 0.4rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  cursor: pointer;
}
.book-row:hover { background: #f9fafb; }
.book-cover-placeholder {
  width: 32px;
  height: 44px;
  background: #ecf0f1;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  flex-shrink: 0;
}
.book-cover-placeholder img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 4px;
}
.book-row .book-info { flex: 1; min-width: 0; }
.book-row .book-info strong { display: block; font-size: 0.95rem; }
.book-row .book-info .sub { font-size: 0.8rem; color: #666; }
.badges { display: flex; flex-wrap: wrap; gap: 0.3rem; margin-top: 0.25rem; }
.badge {
  background: #ecf0f1;
  color: #2c3e50;
  border-radius: 4px;
  padding: 0.15rem 0.5rem;
  font-size: 0.75rem;
}
#emptyMsg { text-align: center; color: #888; margin-top: 2rem; }
#fabAdd {
  position: fixed;
  right: 1.25rem;
  bottom: 1.25rem;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: #2c3e50;
  color: white;
  font-size: 1.8rem;
  border: none;
  box-shadow: 0 3px 8px rgba(0,0,0,0.3);
  cursor: pointer;
  z-index: 15;
  line-height: 1;
}
#fabAdd:hover { background: #34495e; }
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 1rem;
}
.modal-overlay[hidden] { display: none; }
.modal-box {
  background: white;
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
  max-width: 360px;
  width: 90%;
  box-shadow: 0 4px 16px rgba(0,0,0,0.2);
}
.modal-box h3 { margin: 0 0 0.5rem; }
.modal-box p { margin: 0 0 1rem; color: #444; }
.modal-actions { display: flex; justify-content: flex-end; gap: 0.5rem; }
.modal-actions button {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.9rem;
}
#modalBtnSecondary { background: #ecf0f1; color: #2c3e50; }
#modalBtnSecondary:hover { background: #dfe4e6; }
#modalBtnPrimary { background: #2c3e50; color: white; }
#modalBtnPrimary:hover { background: #34495e; }
.add-panel {
  background: white;
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
  max-width: 480px;
  width: 94%;
  max-height: 85vh;
  overflow-y: auto;
  box-shadow: 0 4px 16px rgba(0,0,0,0.2);
}
.add-panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: bold;
  margin-bottom: 0.75rem;
}
.add-panel-header button { background: none; border: none; font-size: 1.2rem; cursor: pointer; }
.add-panel-tabs {
  display: flex;
  gap: 0.4rem;
  margin-bottom: 0.9rem;
  flex-wrap: wrap;
}
.add-tab-btn {
  padding: 0.4rem 0.85rem;
  border: none;
  border-radius: 6px;
  background: #ecf0f1;
  color: #2c3e50;
  font-size: 0.85rem;
  cursor: pointer;
}
.add-tab-btn.active { background: #2c3e50; color: white; font-weight: bold; }
.add-search-panel { margin-bottom: 0.75rem; }
.search-row { display: flex; gap: 0.5rem; margin-bottom: 0.6rem; }
.search-row input {
  flex: 1;
  padding: 0.5rem;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: 1rem;
}
.search-row button {
  padding: 0.5rem 0.9rem;
  border: none;
  border-radius: 6px;
  background: #2c3e50;
  color: white;
  cursor: pointer;
  font-size: 0.9rem;
}
.search-row button:hover { background: #34495e; }
.search-results {
  max-height: 300px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}
.search-result-item {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  background: #f9fafb;
  border-radius: 6px;
  padding: 0.5rem 0.7rem;
  cursor: pointer;
}
.search-result-item:hover { background: #ecf0f1; }
.search-result-cover {
  width: 32px;
  height: 44px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #ecf0f1;
  border-radius: 4px;
  overflow: hidden;
  font-size: 1.1rem;
}
.search-result-cover img { width: 100%; height: 100%; object-fit: cover; }
.search-result-info strong { display: block; font-size: 0.9rem; }
.search-result-info .sub { font-size: 0.78rem; color: #666; }
.search-status, .search-no-results {
  color: #888;
  font-size: 0.85rem;
  text-align: center;
  padding: 0.5rem 0;
}
#scanVideoWrap { display: none; }
#scanVideo {
  width: 100%;
  border-radius: 6px;
  background: #000;
  display: block;
}
#scanStartBtn, #scanStopBtn {
  width: 100%;
  padding: 0.6rem;
  border: none;
  border-radius: 6px;
  color: white;
  cursor: pointer;
  font-size: 0.9rem;
}
#scanStartBtn { background: #2c3e50; }
#scanStartBtn:hover { background: #34495e; }
#scanStopBtn { background: #c0392b; margin-top: 0.5rem; }
#scanStopBtn:hover { background: #a93226; }
#addForm {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  justify-content: center;
  margin: 0;
}
#addForm input,
#addForm select {
  padding: 0.5rem;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: 1rem;
  flex: 1 1 140px;
}
#addForm button {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: 6px;
  background: #2c3e50;
  color: white;
  font-size: 1rem;
  cursor: pointer;
  flex: 1 1 100%;
}
#addForm button:hover { background: #34495e; }
#deleteBookBtn { background: #c0392b; }
#deleteBookBtn:hover { background: #a93226; }

/* --- Step 16: library search box, sort menu, shelf filter chips --- */
#librarySearchRow, #sortMenuRow {
  max-width: 600px;
  margin: 0 auto;
  padding: 0.55rem 0.25rem;
  background: #f5f6fa;
}
#librarySearchRow input {
  width: 100%;
  padding: 0.5rem;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: 0.95rem;
}
#sortMenuRow { display: flex; align-items: center; gap: 0.4rem; flex-wrap: wrap; }
#sortMenuRow[hidden] { display: none; }
#sortByLabel { font-size: 0.82rem; color: #666; margin-right: 0.15rem; }
.sort-opt-btn {
  padding: 0.4rem 0.85rem;
  border: none;
  border-radius: 6px;
  background: #ecf0f1;
  color: #2c3e50;
  font-size: 0.85rem;
  cursor: pointer;
}
.sort-opt-btn:hover { background: #dfe4e6; }
.sort-opt-btn.active { background: #2c3e50; color: white; font-weight: bold; }
#shelfChipsRow {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  max-width: 600px;
  margin: 0 auto;
  padding: 0.5rem 0.25rem;
}
.shelf-chip {
  padding: 0.35rem 0.8rem;
  border: none;
  border-radius: 6px;
  background: #ecf0f1;
  color: #2c3e50;
  font-size: 0.82rem;
  cursor: pointer;
}
.shelf-chip:hover { background: #dfe4e6; }
.shelf-chip.active { background: #2c3e50; color: white; font-weight: bold; }
#shelfChipsRow[hidden] { display: none; }

/* --- Step 17: Android polish — safe-area insets + tap target sizes ---
   env(safe-area-inset-*) resolves to 0 on devices without a notch/gesture
   bar, so this is safe everywhere, not just on modern Android phones. */
#topAppBar {
  padding-top: calc(0.7rem + env(safe-area-inset-top));
  padding-left: calc(1rem + env(safe-area-inset-left));
  padding-right: calc(1rem + env(safe-area-inset-right));
}
.page-content {
  padding-left: calc(1rem + env(safe-area-inset-left));
  padding-right: calc(1rem + env(safe-area-inset-right));
  padding-bottom: calc(5rem + env(safe-area-inset-bottom));
}
.side-drawer {
  padding-top: calc(1rem + env(safe-area-inset-top));
  padding-bottom: calc(1rem + env(safe-area-inset-bottom));
}
#fabAdd {
  right: calc(1.25rem + env(safe-area-inset-right));
  bottom: calc(1.25rem + env(safe-area-inset-bottom));
}

/* Bump small icon-only buttons to the standard 44x44px minimum tap target
   recommended for touchscreens, without changing how big they look
   (the icon itself keeps its original font-size). */
#topAppBar button,
.shelf-menu-btn,
#filterBtn,
.drawer-header button,
.add-panel-header button {
  min-width: 44px;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}