/* ============================================================
   Book Library — Full-page reader  (green & white theme)
   Layout: header | sidebar + pdf-viewer + info-panel | toolbar
   ============================================================ */

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

:root {
  --green-900: #1b4332;
  --green-800: #2d6a4f;
  --green-700: #40916c;
  --green-600: #52b788;
  --green-200: #d8f3dc;
  --green-100: #eaf7ec;
  --green-50 : #f4fdf6;
  --border   : #cde8d2;
  --text-dark : #0f2518;
  --text-mid  : #3a6349;
  --text-light: #6b9e80;
  --white     : #ffffff;
  --bg-viewer : #e8f5ea;
}

/* dark mode vars */
body.dark-mode {
  --white     : #1a2e1c;
  --bg-viewer : #111d13;
  --border    : #2d4a32;
  --text-dark : #e2f0e6;
  --text-mid  : #93c4a5;
  --text-light: #6b9e80;
  --green-50  : #1e3322;
  --green-100 : #1e3322;
}

html, body {
  height: 100%;
  overflow: hidden;
  font-family: 'Inter', 'Segoe UI', Roboto, system-ui, sans-serif;
  font-size: 14px;
  color: var(--text-dark);
  background: var(--green-50);
  transition: background 0.25s, color 0.25s;
}

/* ================================================================
   GRID LAYOUT
   ================================================================ */
.reader-app {
  display: grid;
  grid-template-columns: 260px 1fr 240px;
  grid-template-rows: 58px 1fr 54px;
  height: 100vh;
  transition: grid-template-columns 0.2s;
}
.reader-app.sidebar-collapsed { grid-template-columns: 0 1fr 240px; }
.reader-app.info-collapsed     { grid-template-columns: 260px 1fr 0; }
.reader-app.sidebar-collapsed.info-collapsed { grid-template-columns: 0 1fr 0; }

/* ================================================================
   HEADER
   ================================================================ */
.reader-header {
  grid-column: 1 / -1;
  grid-row: 1 / 2;
  display: flex;
  align-items: center;
  padding: 0 18px;
  background: var(--green-900);
  border-bottom: 1px solid var(--green-800);
  gap: 14px;
  z-index: 20;
  box-shadow: 0 1px 4px rgba(0,0,0,0.2);
}

.header-logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: #fff;
  display: flex;
  align-items: center;
  gap: 8px;
  white-space: nowrap;
}
.header-logo i { color: var(--green-600); }

.header-title {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  line-height: 1.25;
}
.header-title .book-name {
  font-weight: 600;
  font-size: 0.95rem;
  color: #fff;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.header-title .book-author {
  font-size: 0.72rem;
  color: var(--green-600);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
}

.btn-back {
  background: rgba(255,255,255,0.12);
  border: 1px solid rgba(255,255,255,0.2);
  padding: 5px 14px;
  border-radius: 30px;
  font-weight: 500;
  font-size: 0.82rem;
  gap: 6px;
  cursor: pointer;
  color: #fff;
  display: flex;
  align-items: center;
  transition: 0.15s;
}
.btn-back:hover { background: rgba(255,255,255,0.22); }

.btn-icon {
  background: transparent;
  border: none;
  font-size: 1rem;
  padding: 7px 9px;
  border-radius: 8px;
  cursor: pointer;
  color: #c8e6c9;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: 0.15s;
}
.btn-icon:hover { background: rgba(255,255,255,0.12); color: #fff; }

/* ================================================================
   SIDEBAR
   ================================================================ */
.sidebar {
  grid-column: 1 / 2;
  grid-row: 2 / 3;
  background: var(--white);
  border-right: 1px solid var(--border);
  padding: 14px 10px;
  overflow-y: auto;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  gap: 18px;
  transition: all 0.2s;
}

.sidebar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 4px;
}
.sidebar-header h4 {
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--text-dark);
  display: flex;
  align-items: center;
  gap: 7px;
}
.sidebar-header h4 i { color: var(--green-700); }

.sidebar-close {
  background: none;
  border: none;
  font-size: 1rem;
  cursor: pointer;
  color: var(--text-light);
  padding: 4px;
  border-radius: 6px;
  transition: 0.15s;
}
.sidebar-close:hover { color: var(--text-dark); background: var(--green-100); }

.sidebar-nav { display: flex; flex-direction: column; gap: 2px; }

.sidebar-item {
  padding: 9px 10px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  color: var(--text-dark);
  transition: 0.12s;
}
.sidebar-item i { width: 18px; color: var(--green-700); font-size: 0.9rem; }
.sidebar-item:hover { background: var(--green-100); color: var(--green-900); }

.sidebar-progress {
  margin-top: auto;
  border-top: 1px solid var(--border);
  padding-top: 14px;
}
.progress-label { font-size: 0.72rem; font-weight: 600; color: var(--text-light); text-transform: uppercase; letter-spacing: 0.5px; }
.progress-bar { height: 6px; background: var(--green-200); border-radius: 12px; margin: 8px 0 5px; overflow: hidden; }
.progress-fill { height: 100%; background: var(--green-700); border-radius: 12px; width: 0%; transition: width 0.4s; }
.progress-pct { font-size: 0.72rem; color: var(--text-light); font-weight: 500; }

/* Scrollbar */
.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--green-200); border-radius: 8px; }

/* ================================================================
   PDF VIEWER  (scrollable, all pages)
   ================================================================ */
.pdf-viewer {
  grid-column: 2 / 3;
  grid-row: 2 / 3;
  background: var(--bg-viewer);
  overflow-y: auto;
  overflow-x: auto;
  padding: 24px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
}

.pdf-viewer::-webkit-scrollbar { width: 7px; }
.pdf-viewer::-webkit-scrollbar-thumb { background: var(--green-200); border-radius: 10px; }
body.dark-mode .pdf-viewer::-webkit-scrollbar-thumb { background: #2d4a32; }

.pdf-page-container {
  width: 100%;
  max-width: 900px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
  padding-bottom: 20px;
}

.pdf-page {
  background: #fff;
  box-shadow: 0 6px 24px rgba(27,67,50,0.12), 0 2px 6px rgba(0,0,0,0.04);
  border-radius: 4px;
  width: 100%;
}
.pdf-page canvas {
  display: block;
  width: 100% !important;
  height: auto !important;
  border-radius: 4px;
}

.pdf-loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 60vh;
  gap: 14px;
  color: var(--text-light);
}
.pdf-loading i { font-size: 2.2rem; color: var(--green-700); }
.pdf-loading span { font-weight: 500; font-size: 0.9rem; }

.pdf-error {
  color: #b91c1c;
  background: #fee2e2;
  padding: 18px 28px;
  border-radius: 14px;
  font-weight: 500;
  margin-top: 30px;
  display: none;
}

/* ================================================================
   INFO PANEL
   ================================================================ */
.info-panel {
  grid-column: 3 / 4;
  grid-row: 2 / 3;
  background: var(--white);
  border-left: 1px solid var(--border);
  padding: 18px 14px;
  overflow-y: auto;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: all 0.2s;
}

.info-panel::-webkit-scrollbar { width: 4px; }
.info-panel::-webkit-scrollbar-thumb { background: var(--green-200); border-radius: 8px; }

.info-cover {
  width: 100%;
  aspect-ratio: 3/4;
  background: var(--green-100);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
  color: var(--green-700);
  overflow: hidden;
  border: 1px solid var(--border);
}
.info-cover img { width: 100%; height: 100%; object-fit: cover; border-radius: 10px; }

.info-field {
  display: flex;
  justify-content: space-between;
  font-size: 0.82rem;
  border-bottom: 1px solid var(--green-100);
  padding-bottom: 8px;
  gap: 8px;
  align-items: flex-start;
}
.info-label { color: var(--text-light); font-weight: 500; flex-shrink: 0; }
.info-value { font-weight: 600; color: var(--text-dark); text-align: right; }

.info-actions { display: flex; flex-direction: column; gap: 8px; margin-top: 6px; }

.btn-primary {
  background: var(--green-800);
  color: #fff;
  border: none;
  padding: 10px;
  border-radius: 30px;
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: 0.15s;
}
.btn-primary:hover { background: var(--green-900); }

.btn-secondary {
  background: var(--green-100);
  border: 1px solid var(--border);
  padding: 10px;
  border-radius: 30px;
  font-weight: 500;
  font-size: 0.85rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  color: var(--green-900);
  transition: 0.15s;
}
.btn-secondary:hover { background: var(--green-200); }

/* ================================================================
   TOOLBAR (bottom bar)
   ================================================================ */
.toolbar {
  grid-column: 1 / -1;
  grid-row: 3 / 4;
  background: var(--white);
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  padding: 0 14px;
  flex-wrap: nowrap;
  box-shadow: 0 -1px 3px rgba(27,67,50,0.05);
}

.toolbar-btn {
  background: transparent;
  border: none;
  padding: 7px 12px;
  border-radius: 30px;
  font-size: 0.82rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 5px;
  cursor: pointer;
  color: var(--text-dark);
  transition: 0.12s;
  white-space: nowrap;
}
.toolbar-btn:hover { background: var(--green-100); color: var(--green-900); }
.toolbar-btn i { font-size: 0.82rem; }

.toolbar-page {
  font-weight: 600;
  font-size: 0.88rem;
  min-width: 90px;
  text-align: center;
  color: var(--text-dark);
}
.toolbar-sep {
  width: 1px;
  height: 22px;
  background: var(--border);
  margin: 0 2px;
  flex-shrink: 0;
}

/* ================================================================
   DARK MODE overrides
   ================================================================ */
body.dark-mode .reader-header { background: #0f2518; border-color: #1b3a20; }
body.dark-mode .sidebar,
body.dark-mode .info-panel,
body.dark-mode .toolbar { background: #1a2e1c; border-color: #2d4a32; }
body.dark-mode .pdf-page { background: #f4fdf6; box-shadow: 0 8px 24px rgba(0,0,0,0.55); }
body.dark-mode .sidebar-item:hover { background: #253d29; }
body.dark-mode .info-field { border-color: #253d29; }
body.dark-mode .btn-secondary { background: #253d29; border-color: #2d4a32; color: #c8e6c9; }
body.dark-mode .btn-icon { color: #93c4a5; }
body.dark-mode .toolbar-btn { color: #c8e6c9; }
body.dark-mode .toolbar-btn:hover { background: #253d29; color: #fff; }
body.dark-mode .toolbar-page { color: #c8e6c9; }
body.dark-mode .sidebar-header h4 { color: #c8e6c9; }
body.dark-mode .info-value { color: #c8e6c9; }
body.dark-mode .info-cover { background: #253d29; border-color: #2d4a32; }
body.dark-mode .pdf-error { background: #332222; color: #fca5a5; }

/* ================================================================
   RESPONSIVE
   ================================================================ */
@media (max-width: 900px) {
  .reader-app {
    grid-template-columns: 220px 1fr 200px;
  }
}
@media (max-width: 820px) {
  .reader-app {
    grid-template-columns: 1fr;
    grid-template-rows: 58px 1fr 54px;
  }
  .sidebar, .info-panel { display: none; }
  .pdf-viewer { grid-column: 1 / 2; }
  .toolbar { grid-column: 1 / 2; }
}
@media (max-width: 480px) {
  .header-title .book-name { font-size: 0.82rem; }
  .toolbar-btn span { display: none; }
  .toolbar-btn { padding: 6px 9px; }
}

/* ── Lazy-render placeholder shells ── */
.pdf-page-shell {
  display: flex;
  align-items: center;
  justify-content: center;
  background: #fff;
  border-radius: 4px;
  box-shadow: 0 6px 24px rgba(27,67,50,0.10), 0 2px 6px rgba(0,0,0,0.04);
  max-width: 900px;
  width: 100%;
}

.pdf-page-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  color: #b0ccb8;
  height: 100%;
  width: 100%;
}
.pdf-page-placeholder i   { font-size: 2.2rem; }
.pdf-page-placeholder span { font-size: 0.82rem; font-weight: 500; letter-spacing: 0.3px; }

body.dark-mode .pdf-page-shell        { background: #f4fdf6; }
body.dark-mode .pdf-page-placeholder  { color: #6b9e80; }