/* ==============================
   CSS VARIABLES — Default Theme
   ============================== */
:root {
  --bg: #f4f6fb;
  --card-bg: #fff;
  --text: #222;
  --text-muted: #777;
  --text-subtle: #888;
  --accent: #1a73e8;
  --accent-shadow: rgba(26,115,232,0.18);
  --accent-shadow-hover: rgba(26,115,232,0.15);
  --header-bg: #1a73e8;
  --header-text: #fff;
  --border: #e8ecf4;
  --shadow: rgba(0,0,0,0.08);
  --footer-bg: #fff;
  --footer-border: #e0e0e0;
  --footer-text: #888;
  --search-bg: #fff;
  --search-shadow: rgba(0,0,0,0.07);
  --section-title-color: #333;
  --book-bg: #fff;
  --book-border: #e8ecf4;
  --book-title: #1a73e8;
  --book-divider: #e8f0fe;
  --back-btn-bg: rgba(255,255,255,0.2);
  --back-btn-hover: rgba(255,255,255,0.35);
  --transition: 0.3s ease;
}

/* ==============================
   Dark Mode Theme
   ============================== */
[data-theme="dark"] {
  --bg: #0f1117;
  --card-bg: #1e2130;
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --text-subtle: #64748b;
  --accent: #60a5fa;
  --accent-shadow: rgba(96,165,250,0.2);
  --accent-shadow-hover: rgba(96,165,250,0.2);
  --header-bg: #1e2130;
  --header-text: #e2e8f0;
  --border: #2d3748;
  --shadow: rgba(0,0,0,0.4);
  --footer-bg: #1e2130;
  --footer-border: #2d3748;
  --footer-text: #64748b;
  --search-bg: #1e2130;
  --search-shadow: rgba(0,0,0,0.25);
  --section-title-color: #cbd5e1;
  --book-bg: #252a3d;
  --book-border: #2d3748;
  --book-title: #60a5fa;
  --book-divider: #2d3748;
  --back-btn-bg: rgba(255,255,255,0.1);
  --back-btn-hover: rgba(255,255,255,0.18);
}

/* ==============================
   iOS Style Theme (Glassmorphism)
   ============================== */
[data-theme="ios"] {
  --bg: #f2f2f7;
  --card-bg: rgba(255,255,255,0.82);
  --text: #1c1c1e;
  --text-muted: #8e8e93;
  --text-subtle: #aeaeb2;
  --accent: #007aff;
  --accent-shadow: rgba(0,122,255,0.2);
  --accent-shadow-hover: rgba(0,122,255,0.18);
  --header-bg: rgba(242,242,247,0.85);
  --header-text: #1c1c1e;
  --border: rgba(60,60,67,0.12);
  --shadow: rgba(0,0,0,0.05);
  --footer-bg: rgba(255,255,255,0.82);
  --footer-border: rgba(60,60,67,0.12);
  --footer-text: #aeaeb2;
  --search-bg: rgba(255,255,255,0.82);
  --search-shadow: rgba(0,0,0,0.04);
  --section-title-color: #3a3a3c;
  --book-bg: rgba(255,255,255,0.75);
  --book-border: rgba(60,60,67,0.1);
  --book-title: #007aff;
  --book-divider: rgba(0,122,255,0.1);
  --back-btn-bg: rgba(60,60,67,0.1);
  --back-btn-hover: rgba(60,60,67,0.18);
}

/* ==============================
   Minimal Grayscale Theme
   ============================== */
[data-theme="grayscale"] {
  --bg: #f0f0f0;
  --card-bg: #fff;
  --text: #111;
  --text-muted: #666;
  --text-subtle: #888;
  --accent: #333;
  --accent-shadow: rgba(0,0,0,0.12);
  --accent-shadow-hover: rgba(0,0,0,0.14);
  --header-bg: #222;
  --header-text: #fff;
  --border: #d0d0d0;
  --shadow: rgba(0,0,0,0.07);
  --footer-bg: #fff;
  --footer-border: #d0d0d0;
  --footer-text: #888;
  --search-bg: #fff;
  --search-shadow: rgba(0,0,0,0.06);
  --section-title-color: #333;
  --book-bg: #fff;
  --book-border: #d0d0d0;
  --book-title: #333;
  --book-divider: #eee;
  --back-btn-bg: rgba(255,255,255,0.15);
  --back-btn-hover: rgba(255,255,255,0.28);
}

/* ==============================
   Soft Pastel Theme
   ============================== */
[data-theme="pastel"] {
  --bg: #fdf6f0;
  --card-bg: #fff8fc;
  --text: #3d2b3d;
  --text-muted: #9b7faa;
  --text-subtle: #b89fbe;
  --accent: #9c6fcd;
  --accent-shadow: rgba(156,111,205,0.18);
  --accent-shadow-hover: rgba(156,111,205,0.15);
  --header-bg: #e8d5f5;
  --header-text: #3d2b3d;
  --border: #f0dff8;
  --shadow: rgba(156,111,205,0.08);
  --footer-bg: #fff8fc;
  --footer-border: #f0dff8;
  --footer-text: #b89fbe;
  --search-bg: #fff8fc;
  --search-shadow: rgba(156,111,205,0.06);
  --section-title-color: #5b2d8e;
  --book-bg: #fff8fc;
  --book-border: #f0dff8;
  --book-title: #7c3aed;
  --book-divider: #f0dff8;
  --back-btn-bg: rgba(156,111,205,0.12);
  --back-btn-hover: rgba(156,111,205,0.22);
}

/* ==============================
   Reset & Base
   ============================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color var(--transition), color var(--transition);
}

/* ==============================
   Header
   ============================== */
header {
  background: var(--header-bg);
  color: var(--header-text);
  padding: 1.2rem 2rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  box-shadow: 0 2px 6px var(--shadow);
  transition: background-color var(--transition), color var(--transition), box-shadow var(--transition);
}

[data-theme="ios"] header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  box-shadow: none;
}

header h1 {
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: 0.5px;
}

header a {
  color: var(--header-text);
  text-decoration: none;
}

header a:hover {
  text-decoration: underline;
}

.back-btn {
  background: var(--back-btn-bg);
  border: none;
  color: var(--header-text);
  padding: 0.4rem 0.9rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.9rem;
  text-decoration: none;
  transition: background var(--transition);
}

.back-btn:hover {
  background: var(--back-btn-hover);
  text-decoration: none;
}

/* ==============================
   Main
   ============================== */
main {
  flex: 1;
  padding: 2rem;
  max-width: 1100px;
  margin: 0 auto;
  width: 100%;
}

/* ==============================
   Hero
   ============================== */
.hero {
  text-align: center;
  margin-bottom: 2.5rem;
}

.hero h2 {
  font-size: 2rem;
  color: var(--accent);
  margin-bottom: 0.5rem;
  transition: color var(--transition);
}

.hero p {
  color: var(--text-muted);
  font-size: 1.05rem;
  transition: color var(--transition);
}

/* ==============================
   Subject Cards
   ============================== */
.subjects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-top: 1rem;
}

.subject-card {
  background: var(--card-bg);
  border-radius: 14px;
  padding: 2rem 1.5rem;
  text-align: center;
  text-decoration: none;
  color: var(--text);
  box-shadow: 0 2px 10px var(--shadow);
  transition: transform 0.2s, box-shadow 0.2s, background-color var(--transition), color var(--transition), border-color var(--transition);
  border: 2px solid transparent;
}

[data-theme="ios"] .subject-card {
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.subject-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 20px var(--accent-shadow);
  border-color: var(--accent);
  color: var(--accent);
}

.subject-card .icon {
  font-size: 3rem;
  margin-bottom: 0.8rem;
  display: block;
}

.subject-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
}

.subject-card p {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.3rem;
  transition: color var(--transition);
}

/* ==============================
   Search Bar
   ============================== */
.search-bar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
  background: var(--search-bg);
  border-radius: 10px;
  padding: 0.5rem 1rem;
  box-shadow: 0 2px 8px var(--search-shadow);
  transition: background-color var(--transition), box-shadow var(--transition);
}

[data-theme="ios"] .search-bar {
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.search-bar input {
  flex: 1;
  border: none;
  outline: none;
  font-size: 1rem;
  color: var(--text);
  background: transparent;
  transition: color var(--transition);
}

.search-bar .search-icon {
  color: var(--text-subtle);
  font-size: 1.1rem;
}

/* ==============================
   File List
   ============================== */
.section-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--section-title-color);
  border-left: 4px solid var(--accent);
  padding-left: 0.75rem;
  transition: color var(--transition), border-color var(--transition);
}

.appwrite-divider {
  margin-top: 2rem;
}

.file-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1rem;
  justify-content: center;
  justify-items: center;
}

.file-card {
  background: var(--card-bg);
  border-radius: 10px;
  padding: 1rem 1.2rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text);
  box-shadow: 0 2px 8px var(--shadow);
  transition: transform 0.15s, box-shadow 0.15s, border-color var(--transition), background-color var(--transition), color var(--transition);
  border: 1.5px solid var(--border);
  width: 100%;
}

[data-theme="ios"] .file-card {
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.file-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 5px 16px var(--accent-shadow-hover);
  border-color: var(--accent);
  color: var(--accent);
}

.file-card .pdf-icon {
  font-size: 1.6rem;
  flex-shrink: 0;
}

.file-card .file-name {
  font-size: 0.95rem;
  font-weight: 500;
  line-height: 1.3;
}

.file-count-label {
  font-size: 0.85rem;
  font-weight: 400;
  color: var(--text-subtle);
  margin-left: 0.5rem;
}

/* ==============================
   Empty / Loading
   ============================== */
.status-msg {
  text-align: center;
  color: var(--text-subtle);
  padding: 3rem 1rem;
  font-size: 1rem;
}

.no-results {
  text-align: center;
  color: var(--text-muted);
  padding: 2rem 1rem;
  font-size: 0.95rem;
}

/* ==============================
   Book Sections
   ============================== */
.sections-container {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.book-section {
  background: var(--book-bg);
  border-radius: 12px;
  padding: 1.25rem 1.5rem;
  box-shadow: 0 2px 8px var(--shadow);
  border: 1px solid var(--book-border);
  transition: background-color var(--transition), border-color var(--transition), box-shadow var(--transition);
}

[data-theme="ios"] .book-section {
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.book-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--book-title);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--book-divider);
  letter-spacing: 0.2px;
  transition: color var(--transition), border-color var(--transition);
}

/* ==============================
   Footer
   ============================== */
footer {
  background: var(--footer-bg);
  border-top: 1px solid var(--footer-border);
  text-align: center;
  padding: 1rem;
  color: var(--footer-text);
  font-size: 0.85rem;
  transition: background-color var(--transition), border-color var(--transition), color var(--transition);
}

/* ==============================
   Settings Button (in header)
   ============================== */
.settings-btn {
  margin-left: auto;
  background: var(--back-btn-bg);
  border: none;
  color: var(--header-text);
  width: 2.2rem;
  height: 2.2rem;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: background var(--transition), color var(--transition);
  line-height: 1;
}

.settings-btn:hover {
  background: var(--back-btn-hover);
}

/* ==============================
   Settings Overlay
   ============================== */
.settings-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.35);
  z-index: 998;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

.settings-overlay.open {
  opacity: 1;
  pointer-events: auto;
}

/* ==============================
   Settings Panel
   ============================== */
.settings-panel {
  position: fixed;
  top: 0;
  right: 0;
  width: 300px;
  max-width: 90vw;
  height: 100vh;
  height: 100dvh;
  background: var(--card-bg);
  border-left: 1px solid var(--border);
  box-shadow: -4px 0 28px rgba(0,0,0,0.14);
  z-index: 999;
  display: flex;
  flex-direction: column;
  transform: translateX(100%);
  transition: transform 0.3s ease, background-color var(--transition), border-color var(--transition);
}

[data-theme="ios"] .settings-panel {
  background: rgba(242,242,247,0.88);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
}

.settings-panel.open {
  transform: translateX(0);
}

.settings-panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.2rem 1.5rem;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  transition: border-color var(--transition);
}

.settings-panel-header h2 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text);
  transition: color var(--transition);
}

.settings-close-btn {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 1rem;
  line-height: 1;
  padding: 0.3rem 0.5rem;
  border-radius: 6px;
  transition: background 0.2s, color 0.2s;
}

.settings-close-btn:hover {
  background: var(--border);
  color: var(--text);
}

.settings-panel-body {
  flex: 1;
  padding: 1.5rem;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
}

.settings-section-label {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  color: var(--text-muted);
  transition: color var(--transition);
}

/* ==============================
   Theme Buttons
   ============================== */
.theme-list {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.settings-theme-btn {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  width: 100%;
  background: var(--bg);
  border: 2px solid var(--border);
  border-radius: 10px;
  padding: 0.6rem 0.85rem;
  cursor: pointer;
  color: var(--text);
  font-size: 0.9rem;
  font-weight: 500;
  text-align: left;
  transition: border-color 0.2s, background-color 0.2s, color 0.2s;
}

.settings-theme-btn:hover {
  border-color: var(--accent);
}

.settings-theme-btn.active {
  border-color: var(--accent);
  background: var(--card-bg);
  color: var(--accent);
}

.theme-swatch {
  width: 26px;
  height: 26px;
  border-radius: 6px;
  flex-shrink: 0;
  border: 1px solid rgba(0,0,0,0.08);
}

/* ==============================
   Random Theme Button
   ============================== */
.random-theme-btn {
  width: 100%;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 10px;
  padding: 0.75rem 1rem;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.15s, background-color var(--transition);
  letter-spacing: 0.01em;
  margin-top: 0.3rem;
}

.random-theme-btn:hover {
  opacity: 0.88;
  transform: translateY(-1px);
}

.random-theme-btn:active {
  transform: translateY(0);
}

/* ==============================
   Bulk Open Bar
   ============================== */
.bulk-open-bar {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.bulk-open-scope {
  background: var(--card-bg);
  color: var(--text);
  border: 1.5px solid var(--border);
  border-radius: 8px;
  padding: 0.45rem 0.8rem;
  font-size: 0.9rem;
  cursor: pointer;
  outline: none;
  transition: border-color var(--transition), background-color var(--transition), color var(--transition);
}

.bulk-open-scope:focus,
.bulk-open-scope:hover {
  border-color: var(--accent);
}

.bulk-open-btn {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 0.45rem 1rem;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: opacity 0.2s, transform 0.15s, background-color var(--transition);
}

.bulk-open-btn:hover {
  opacity: 0.88;
  transform: translateY(-1px);
}

.bulk-open-btn:active {
  transform: translateY(0);
}

.bulk-open-status {
  font-size: 0.85rem;
  color: var(--text-muted);
  transition: color var(--transition);
}

/* ==============================
   Timetable Nav Button (index)
   ============================== */
.tt-nav-bar {
  display: flex;
  justify-content: center;
  margin-bottom: 2rem;
}

.tt-nav-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  border-radius: 12px;
  padding: 0.7rem 1.6rem;
  font-size: 1rem;
  font-weight: 600;
  box-shadow: 0 2px 10px var(--accent-shadow);
  transition: opacity 0.2s, transform 0.15s, background-color var(--transition), box-shadow var(--transition);
  letter-spacing: 0.01em;
}

.tt-nav-btn:hover {
  opacity: 0.88;
  transform: translateY(-2px);
  box-shadow: 0 6px 18px var(--accent-shadow-hover);
}

.tt-nav-btn:active {
  transform: translateY(0);
}

/* ==============================
   Timetable Page
   ============================== */
.tt-meta {
  text-align: center;
  margin-bottom: 1.5rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  transition: color var(--transition);
}

.tt-scroll {
  width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border-radius: 14px;
  box-shadow: 0 2px 12px var(--shadow);
}

.tt-table {
  border-collapse: collapse;
  width: 100%;
  table-layout: fixed;
  background: var(--card-bg);
  border-radius: 14px;
  overflow: hidden;
  transition: background-color var(--transition);
}

/* Day label column width */
.tt-table .tt-day-col {
  width: 110px;
  min-width: 90px;
}

/* Header row */
.tt-table thead th {
  background: var(--accent);
  color: #fff;
  padding: 0.5rem 0.2rem;
  font-size: 0.85rem;
  font-weight: 600;
  text-align: center;
  letter-spacing: 0.03em;
  white-space: normal;
  transition: background-color var(--transition);
}

.tt-table thead th:first-child {
  text-align: left;
  padding-left: 1rem;
  border-radius: 0;
}

/* Body cells */
.tt-table tbody tr {
  height: 50px;
}

.tt-table tbody td,
.tt-table tbody th {
  border: 1px solid var(--border);
  padding: 0.55rem 0.3rem;
  text-align: center;
  font-size: 0.82rem;
  line-height: 1.1;
  color: var(--text);
  background: var(--card-bg);
  vertical-align: middle;
  transition: background-color var(--transition), color var(--transition), border-color var(--transition);
  white-space: normal;
  word-wrap: break-word;
}

.tt-table tbody .tt-day-col {
  text-align: left;
  padding-left: 1rem;
  font-weight: 600;
  background: var(--bg);
  min-width: 90px;
}

.tt-table tbody tr:first-child td,
.tt-table tbody tr:first-child th {
  border-top: none;
}

/* Period label + time in column headers */
.tt-period-name {
  display: block;
  font-size: 0.88rem;
  font-weight: 600;
  transition: color var(--transition);
}

.tt-period-time {
  display: block;
  font-size: 0.73rem;
  margin-top: 1px;
  opacity: 0.78;
  transition: color var(--transition);
}

/* Break / Lunch columns */
.tt-table tbody td.tt-row-break {
  background: var(--book-divider);
  color: var(--text-muted);
  font-style: italic;
  font-size: 0.82rem;
}

/* Current period column highlight */
.tt-table tbody td.tt-current {
  background: rgba(0, 0, 0, 0.03);
}

.tt-table thead th.tt-current {
  background: color-mix(in srgb, #fff 18%, var(--accent));
}

/* Today row highlight */
.tt-table th.tt-today,
.tt-table td.tt-today {
  background: color-mix(in srgb, var(--accent) 8%, var(--card-bg));
}

.tt-table .tt-today.tt-day-col {
  background: color-mix(in srgb, var(--accent) 8%, var(--bg));
}

/* Today row + break/lunch column */
.tt-table tbody td.tt-today.tt-row-break {
  background: color-mix(in srgb, var(--accent) 8%, var(--book-divider));
}

/* Today row + current period column */
.tt-table tbody td.tt-today.tt-current {
  background: color-mix(in srgb, var(--accent) 18%, var(--card-bg));
}

/* Current-period badge */
.tt-now-badge {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  font-size: 0.6rem;
  font-weight: 700;
  border-radius: 4px;
  padding: 1px 5px;
  margin-left: 4px;
  vertical-align: middle;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

/* Badge is inside a header <th> (blue bg in default/ios themes) — flip to white pill */
.tt-table thead th .tt-now-badge {
  background: rgba(255, 255, 255, 0.9);
  color: var(--accent);
}

/* Minimal tt-theme has a light header — keep blue badge */
[data-tt-theme="minimal"] .tt-table thead th .tt-now-badge {
  background: var(--accent);
  color: #fff;
}

/* ==============================
   Timetable Themes
   ============================== */

/* — iOS (glassmorphism) — */
[data-tt-theme="ios"] .tt-table {
  background: rgba(255, 255, 255, 0.55);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border: 1px solid rgba(60, 60, 67, 0.12);
}

[data-tt-theme="ios"] .tt-table thead th {
  background: rgba(0, 122, 255, 0.82);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

[data-tt-theme="ios"] .tt-table tbody td,
[data-tt-theme="ios"] .tt-table tbody th {
  background: rgba(255, 255, 255, 0.45);
  border-color: rgba(60, 60, 67, 0.1);
}

[data-tt-theme="ios"] .tt-table tbody .tt-day-col {
  background: rgba(242, 242, 247, 0.6);
}

[data-tt-theme="ios"] .tt-table tbody td.tt-row-break {
  background: rgba(0, 122, 255, 0.07);
}

[data-tt-theme="ios"] .tt-table tbody td.tt-current {
  background: rgba(0, 122, 255, 0.13);
}

/* — Minimal — */
[data-tt-theme="minimal"] .tt-table {
  box-shadow: none;
  border: 1px solid var(--border);
}

[data-tt-theme="minimal"] .tt-table thead th {
  background: var(--bg);
  color: var(--text-muted);
  font-weight: 500;
  border-bottom: 2px solid var(--border);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

[data-tt-theme="minimal"] .tt-period-name {
  color: var(--text);
}

[data-tt-theme="minimal"] .tt-period-time {
  color: var(--text-muted);
  opacity: 1;
}

[data-tt-theme="minimal"] .tt-table tbody td,
[data-tt-theme="minimal"] .tt-table tbody th {
  border-color: var(--border);
  font-size: 0.85rem;
}

[data-tt-theme="minimal"] .tt-table tbody td.tt-current {
  background: rgba(0, 0, 0, 0.03);
}

[data-tt-theme="minimal"] .tt-table thead th.tt-current {
  outline: none;
}

/* — Dark (always dark cells) — */
[data-tt-theme="dark"] .tt-scroll {
  box-shadow: 0 2px 16px rgba(0, 0, 0, 0.4);
}

[data-tt-theme="dark"] .tt-table {
  background: #1e2130;
}

[data-tt-theme="dark"] .tt-table thead th {
  background: #252a3d;
  color: #60a5fa;
  border-bottom: 2px solid #2d3748;
}

[data-tt-theme="dark"] .tt-table tbody td,
[data-tt-theme="dark"] .tt-table tbody th {
  background: #1e2130;
  color: #e2e8f0;
  border-color: #2d3748;
}

[data-tt-theme="dark"] .tt-table tbody .tt-day-col {
  background: #161b27;
  color: #94a3b8;
}

[data-tt-theme="dark"] .tt-period-name {
  color: #e2e8f0;
}

[data-tt-theme="dark"] .tt-period-time {
  color: #64748b;
  opacity: 1;
}

[data-tt-theme="dark"] .tt-table tbody td.tt-row-break {
  background: #252a3d;
  color: #64748b;
}

[data-tt-theme="dark"] .tt-table th.tt-today,
[data-tt-theme="dark"] .tt-table td.tt-today {
  background: rgba(96, 165, 250, 0.08);
}

[data-tt-theme="dark"] .tt-table tbody td.tt-current {
  background: rgba(96, 165, 250, 0.12);
}

[data-tt-theme="dark"] .tt-table tbody td.tt-today.tt-current {
  background: rgba(96, 165, 250, 0.2);
}

/* ==============================
   Responsive
   ============================== */
@media (max-width: 600px) {
  main {
    padding: 1.2rem 1rem;
  }

  .hero h2 {
    font-size: 1.5rem;
  }

  .subjects-grid {
    grid-template-columns: 1fr 1fr;
  }
}

/* ==============================
   PDF Viewer Overlay
   ============================== */
.pdf-viewer-overlay {
  position: fixed;
  inset: 0;
  z-index: 1000;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
  background: rgba(0, 0, 0, 0.6);
}

.pdf-viewer-overlay.open {
  opacity: 1;
  pointer-events: auto;
}

/* ==============================
   PDF Viewer Container
   ============================== */
.pdf-viewer-container {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  transition: background-color var(--transition);
}

/* ==============================
   PDF Viewer Toolbar
   ============================== */
.pdf-viewer-toolbar {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.5rem 0.75rem;
  background: var(--header-bg);
  color: var(--header-text);
  flex-shrink: 0;
  box-shadow: 0 2px 6px var(--shadow);
  transition: background-color var(--transition), color var(--transition);
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.pdf-viewer-toolbar::-webkit-scrollbar {
  display: none;
}

/* Generic toolbar button */
.pdf-tb-btn {
  background: transparent;
  border: none;
  color: var(--header-text);
  width: 2rem;
  height: 2rem;
  min-width: 2rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 1rem;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition), color var(--transition);
  padding: 0;
}

.pdf-tb-btn:hover {
  background: var(--back-btn-hover);
}

.pdf-tb-btn.active {
  background: var(--accent);
  color: #fff;
}

/* Close button inherits .pdf-tb-btn */
.pdf-viewer-close-btn {
  background: var(--back-btn-bg);
}

.pdf-viewer-close-btn:hover {
  background: var(--back-btn-hover);
}

/* Separator */
.pdf-tb-sep {
  display: inline-block;
  width: 1px;
  height: 1.4rem;
  background: rgba(255, 255, 255, 0.25);
  flex-shrink: 0;
  margin: 0 0.15rem;
  align-self: center;
}

[data-theme="ios"] .pdf-tb-sep,
[data-theme="grayscale"] .pdf-tb-sep,
[data-theme="pastel"] .pdf-tb-sep {
  background: rgba(0, 0, 0, 0.15);
}

/* Spacer */
.pdf-tb-spacer {
  flex: 1;
  min-width: 0.5rem;
}

/* Page input wrap */
.pdf-tb-page-wrap {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  flex-shrink: 0;
}

/* Shared input style */
.pdf-tb-input {
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.3);
  color: var(--header-text);
  border-radius: 5px;
  padding: 0.2rem 0.35rem;
  font-size: 0.85rem;
  font-family: inherit;
  text-align: center;
  outline: none;
  transition: border-color 0.2s, background 0.2s;
  height: 1.8rem;
}

.pdf-tb-input:focus {
  border-color: rgba(255, 255, 255, 0.7);
  background: rgba(255, 255, 255, 0.25);
}

[data-theme="ios"] .pdf-tb-input,
[data-theme="grayscale"] .pdf-tb-input,
[data-theme="pastel"] .pdf-tb-input {
  background: rgba(0, 0, 0, 0.07);
  border-color: rgba(0, 0, 0, 0.2);
}

[data-theme="ios"] .pdf-tb-input:focus,
[data-theme="grayscale"] .pdf-tb-input:focus,
[data-theme="pastel"] .pdf-tb-input:focus {
  border-color: var(--accent);
}

.pdf-tb-page-input {
  width: 2.8rem;
}

.pdf-tb-zoom-input {
  width: 3.6rem;
}

.pdf-tb-page-total {
  font-size: 0.85rem;
  color: var(--header-text);
  white-space: nowrap;
  opacity: 0.85;
  flex-shrink: 0;
}

/* ==============================
   PDF Viewer Body
   ============================== */
.pdf-viewer-body {
  flex: 1;
  display: flex;
  overflow: hidden;
}

/* ==============================
   Thumbnail Sidebar
   ============================== */
.pdf-thumbnail-sidebar {
  width: 0;
  overflow: hidden;
  overflow-y: auto;
  background: #1e1e1e;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.6rem;
  padding: 0;
  transition: width 0.2s ease;
  -webkit-overflow-scrolling: touch;
}

.pdf-thumbnail-sidebar.open {
  width: 130px;
  padding: 0.75rem 0.5rem;
}

.pdf-thumb {
  cursor: pointer;
  border: 2px solid transparent;
  border-radius: 4px;
  padding: 2px;
  background: #2b2b2b;
  transition: border-color 0.15s, transform 0.15s;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
  width: 100%;
}

.pdf-thumb:hover {
  border-color: var(--accent);
  transform: scale(1.02);
}

.pdf-thumb.active {
  border-color: var(--accent);
  background: var(--accent-shadow);
}

.pdf-thumb-canvas {
  display: block;
  max-width: 100%;
  border-radius: 2px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.4);
}

.pdf-thumb-label {
  font-size: 0.7rem;
  color: #aaa;
  text-align: center;
  line-height: 1;
}

/* ==============================
   PDF Canvas Area
   ============================== */
.pdf-canvas-wrap {
  flex: 1;
  overflow-y: auto;
  overflow-x: auto;
  background: #2b2b2b;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 1.5rem;
  gap: 1.5rem;
  -webkit-overflow-scrolling: touch;
}

.pdf-page-wrapper {
  position: relative;
  line-height: 0;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.5);
  border-radius: 2px;
  flex-shrink: 0;
}

.pdf-page-canvas {
  display: block;
  pointer-events: none; /* text layer sits on top and handles selection */
}

.pdf-page-placeholder {
  display: block;
  background: #3a3a3a;
  border-radius: 2px;
}

.pdf-thumb-placeholder {
  width: 100%;
  aspect-ratio: 3 / 4;
  background: #3a3a3a;
  border-radius: 2px;
  min-height: 60px;
}

.pdf-page-wrapper .textLayer {
  position: absolute;
  top: 0;
  left: 0;
  overflow: visible;
  pointer-events: all;
  /* width/height are set explicitly in JS to match the canvas */
}

.pdf-page-wrapper .textLayer span {
  cursor: text;
  user-select: text;
}

/* Two-page view rows */
.pdf-pair-row {
  display: flex;
  flex-direction: row;
  align-items: flex-start;
  gap: 1rem;
  flex-shrink: 0;
}

.pdf-pair-row--single {
  justify-content: center;
}

.pdf-load-error {
  color: #f87171;
  font-size: 0.95rem;
  text-align: center;
  padding: 3rem 1rem;
}

.pdf-loading-indicator {
  color: #aaa;
  font-size: 0.9rem;
  text-align: center;
  padding: 1.5rem 1rem;
  align-self: center;
}

/* ==============================
   AI Chat Floating Button
   ============================== */
.pdf-ask-ai-fab {
  position: absolute;
  bottom: 1.5rem;
  right: 1.5rem;
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.28);
  transition: transform 0.2s ease, box-shadow 0.2s ease, background-color var(--transition);
  z-index: 10;
  flex-shrink: 0;
}

.pdf-ask-ai-fab:hover {
  transform: scale(1.1);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.35);
}

/* ==============================
   AI Chat Panel
   ============================== */
@keyframes pdf-msg-fadein {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

.pdf-chat-panel {
  position: absolute;
  top: 1rem;
  right: 1rem;
  bottom: 1rem;
  width: 340px;
  max-width: calc(100vw - 2rem);
  height: auto;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.22);
  display: flex;
  flex-direction: column;
  transform: translateX(calc(100% + 1.5rem));
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), background-color var(--transition), border-color var(--transition);
  z-index: 10;
  overflow: hidden;
}

[data-theme="ios"] .pdf-chat-panel {
  background: rgba(242, 242, 247, 0.9);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

.pdf-chat-panel.open {
  transform: translateX(0);
}

/* Resize handles */
.pdf-chat-resize-left,
.pdf-chat-resize-top {
  position: absolute;
  z-index: 20;
  opacity: 0;
  background: var(--accent);
  transition: opacity 0.2s;
}

.pdf-chat-resize-left {
  left: 0;
  top: 0;
  width: 6px;
  height: 100%;
  cursor: ew-resize;
  border-radius: 16px 0 0 16px;
}

.pdf-chat-resize-top {
  top: 0;
  left: 0;
  width: 100%;
  height: 6px;
  cursor: ns-resize;
  border-radius: 16px 16px 0 0;
}

.pdf-chat-panel:hover .pdf-chat-resize-left,
.pdf-chat-panel:hover .pdf-chat-resize-top {
  opacity: 0.25;
}

.pdf-chat-resize-left:hover,
.pdf-chat-resize-top:hover,
.pdf-chat-resize-left:active,
.pdf-chat-resize-top:active {
  opacity: 0.55;
}

.pdf-chat-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1rem 0.85rem;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  transition: border-color var(--transition);
  background: var(--card);
  border-radius: 16px 16px 0 0;
}

.pdf-chat-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  transition: color var(--transition);
}

.pdf-chat-close-btn {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 1rem;
  padding: 0.3rem 0.5rem;
  border-radius: 6px;
  transition: background 0.2s, color 0.2s;
}

.pdf-chat-close-btn:hover {
  background: var(--border);
  color: var(--text);
}

.pdf-chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  -webkit-overflow-scrolling: touch;
}

.pdf-chat-msg {
  padding: 0.6rem 0.85rem;
  border-radius: 16px;
  font-size: 0.9rem;
  line-height: 1.45;
  max-width: 88%;
  white-space: pre-wrap;
  word-break: break-word;
  animation: pdf-msg-fadein 0.22s ease both;
}

.pdf-chat-msg--user {
  background: var(--accent);
  color: #fff;
  align-self: flex-end;
  border-bottom-right-radius: 4px;
}

.pdf-chat-msg--ai {
  background: var(--card);
  color: var(--text);
  align-self: flex-start;
  border-bottom-left-radius: 4px;
  border: 1px solid var(--border);
  transition: background-color var(--transition), color var(--transition), border-color var(--transition);
}

.pdf-chat-input-area {
  display: flex;
  gap: 0.5rem;
  padding: 0.75rem;
  border-top: 1px solid var(--border);
  flex-shrink: 0;
  align-items: flex-end;
  transition: border-color var(--transition);
}

.pdf-chat-input {
  flex: 1;
  background: var(--bg);
  color: var(--text);
  border: 1.5px solid var(--border);
  border-radius: 20px;
  padding: 0.5rem 0.85rem;
  font-size: 0.9rem;
  font-family: inherit;
  resize: none;
  outline: none;
  transition: border-color 0.2s, background-color var(--transition), color var(--transition);
}

.pdf-chat-input:focus {
  border-color: var(--accent);
}

.pdf-chat-send-btn {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 50%;
  width: 36px;
  height: 36px;
  min-width: 36px;
  font-size: 1.05rem;
  cursor: pointer;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: opacity 0.2s, transform 0.15s, background-color var(--transition);
  align-self: flex-end;
}

.pdf-chat-send-btn:hover {
  opacity: 0.88;
  transform: scale(1.1);
}

.pdf-chat-send-btn:active {
  transform: scale(1);
}

.pdf-chat-send-btn:disabled {
  opacity: 0.45;
  cursor: default;
  transform: none;
}

/* ==============================
   Responsive — PDF Viewer
   ============================== */
@media (max-width: 600px) {
  .pdf-viewer-toolbar {
    padding: 0.4rem 0.5rem;
    gap: 0.2rem;
  }

  .pdf-tb-btn {
    width: 1.8rem;
    height: 1.8rem;
    min-width: 1.8rem;
    font-size: 0.9rem;
  }

  .pdf-tb-page-input {
    width: 2.4rem;
  }

  .pdf-tb-zoom-input {
    width: 3rem;
  }

  .pdf-canvas-wrap {
    padding: 0.75rem;
  }

  .pdf-ask-ai-fab {
    bottom: 1rem;
    right: 1rem;
  }

  .pdf-chat-panel {
    left: 0.5rem;
    right: 0.5rem;
    top: auto;
    bottom: 0.5rem;
    width: auto;
    max-width: none;
    height: 72%;
    transform: translateY(calc(100% + 1rem));
    border-radius: 16px;
  }

  .pdf-chat-panel.open {
    transform: translateY(0);
  }
}