:root {
  --bg: #f5f6fa;
  --card: #ffffff;
  --text: #1f2430;
  --muted: #667085;
  --brand: #0B66C3;
  --accent: #F4A93B;
  --primary: #2f5bea;
  --primary-text: #ffffff;
  --border: #dfe3ec;
  --ok: #1a8f4c;
  --warn: #c77700;
  --bad: #c62828;
  --ts-accent: #0B66C3;
  --ts-accent-soft: #eff6fc;
  --ts-surface: #ffffff;
  --ts-surface-2: #faf9f8;
  --ts-canvas-bg: #f3f2f1;
  --ts-hover: #f1f5f9;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12151c;
    --card: #1b2030;
    --text: #e8ebf3;
    --muted: #9aa3b8;
    --border: #2b3248;
    --brand: #6cb0f5;
    --primary: #6b8cff;
    --primary-text: #0d1020;
    --ts-accent: #6cb0f5;
    --ts-accent-soft: #1e293b;
    --ts-surface: #1b2030;
    --ts-surface-2: #161b26;
    --ts-canvas-bg: #12151c;
    --ts-hover: #22293d;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0; font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg); color: var(--text); line-height: 1.5;
}
#topbar {
  display: flex; flex-wrap: wrap; gap: 12px; align-items: center;
  padding: 10px 16px; background: var(--card); border-bottom: 1px solid var(--border);
}
#topbar[hidden] { display: none; }
.brand {
  display: inline-flex; align-items: center; gap: 8px; text-decoration: none;
  font-family: "Quicksand", system-ui, sans-serif; font-weight: 700; font-size: 20px;
  color: var(--brand); line-height: 1;
}
.brand b { color: var(--accent); font-weight: 700; }
#nav { display: flex; gap: 4px; flex-wrap: wrap; flex: 1; }
#nav a { padding: 6px 10px; border-radius: 6px; color: var(--text); text-decoration: none; }
#nav a.active, #nav a:hover { background: var(--bg); }
.who { display: flex; gap: 8px; align-items: center; color: var(--muted); font-size: 14px; }
main { max-width: 1000px; margin: 0 auto; padding: 16px; }
h1 { font-size: 22px; margin: 8px 0 16px; }
h2 { font-size: 17px; margin: 0 0 10px; }
.card {
  background: var(--card); border: 1px solid var(--border); border-radius: 10px;
  padding: 16px; margin-bottom: 16px;
}
.grid { display: grid; gap: 12px; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
a.tile {
  display: block; padding: 18px; border-radius: 10px; background: var(--card);
  border: 1px solid var(--border); color: var(--text); text-decoration: none;
}
a.tile:hover { border-color: var(--primary); }
a.tile strong { display: block; margin-bottom: 4px; }
a.tile span { color: var(--muted); font-size: 14px; }
label { display: block; font-size: 14px; color: var(--muted); margin: 8px 0 4px; }
input, select, textarea {
  width: 100%; padding: 8px 10px; border: 1px solid var(--border); border-radius: 6px;
  background: var(--bg); color: var(--text); font: inherit;
}
button {
  padding: 8px 14px; border: 1px solid var(--border); border-radius: 6px;
  background: var(--card); color: var(--text); font: inherit; cursor: pointer;
}
button.primary { background: var(--primary); color: var(--primary-text); border-color: var(--primary); }
button.danger { color: var(--bad); }
button:disabled { opacity: .5; cursor: not-allowed; }
.row { display: flex; gap: 8px; flex-wrap: wrap; align-items: end; }
.row > * { flex: 1; min-width: 140px; }
.row > button { flex: 0 0 auto; }
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { text-align: left; padding: 8px; border-bottom: 1px solid var(--border); vertical-align: top; }
th { color: var(--muted); font-weight: 600; }
.badge { padding: 2px 8px; border-radius: 99px; font-size: 12px; border: 1px solid var(--border); }
.badge.done { color: var(--ok); border-color: var(--ok); }
.badge.planned { color: var(--primary); border-color: var(--primary); }
.badge.cancelled { color: var(--muted); }
.badge.absent { color: var(--bad); border-color: var(--bad); }
.muted { color: var(--muted); }
.empty { color: var(--muted); padding: 12px 0; }
.narrow { max-width: 380px; margin: 40px auto; }
.tabs { display: flex; gap: 8px; margin-bottom: 8px; }
.tabs button.on { background: var(--primary); color: var(--primary-text); border-color: var(--primary); }
#toast {
  position: fixed; left: 50%; bottom: 20px; transform: translateX(-50%);
  background: var(--text); color: var(--bg); padding: 10px 16px; border-radius: 8px; z-index: 10;
}
#toast[hidden] { display: none; }
@media (max-width: 600px) {
  th:nth-child(n+4), td:nth-child(n+4) { font-size: 13px; }
}

/* Κουμπί-σύνδεσμος (π.χ. «Σύνδεση» στο δωμάτιο) */
a.btn {
  display: inline-block; padding: 8px 14px; border: 1px solid var(--border); border-radius: 6px;
  background: var(--card); color: var(--text); text-decoration: none; font: inherit;
}
a.btn.primary { background: var(--primary); color: var(--primary-text); border-color: var(--primary); }
label.check { display: flex; gap: 8px; align-items: center; color: var(--text); margin: 4px 0; }
label.check input { width: auto; }
.badge.pending { color: var(--warn); border-color: var(--warn); }
.badge.approved, .badge.accepted { color: var(--ok); border-color: var(--ok); }
.badge.rejected, .badge.declined { color: var(--bad); border-color: var(--bad); }
.badge.draft { color: var(--muted); }
.spaced > * + * { margin-top: 8px; }
label.field { display: block; }
label.field input, label.field textarea, label.field select { margin-top: 4px; }
.row-line { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; margin: 2px 0; }
.row-line select { width: auto; }
.error { color: #b00020; font-weight: 600; }

/* ---------- Τετράδια Πολλών Θεμάτων, Καμβάς Γραφίδας & Jitsi ---------- */
main { max-width: 1220px; }
.nb-shell {
  background: var(--card); border: 1px solid var(--border); border-radius: 10px;
  overflow: hidden; margin-bottom: 20px;
}
.nb-sections-bar {
  display: flex; gap: 4px; flex-wrap: wrap; padding: 8px 10px 0;
  background: var(--bg); border-bottom: 1px solid var(--border);
}
.nb-section-tab {
  border-radius: 8px 8px 0 0; border-bottom: none; font-weight: 600;
  padding: 8px 14px; background: var(--card); opacity: 0.78;
}
.nb-section-tab.active {
  opacity: 1; background: var(--card); box-shadow: 0 -2px 6px rgba(0,0,0,0.05);
}
.nb-section-add {
  border-style: dashed; padding: 6px 12px; font-size: 13px; margin-bottom: 4px;
}
.nb-pages-bar {
  display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap;
  gap: 8px; padding: 8px 12px; border-bottom: 1px solid var(--border); background: var(--card);
}
.nb-page-tab {
  padding: 5px 11px; font-size: 13px; border-radius: 6px;
}
.nb-page-tab.active {
  background: var(--primary); color: var(--primary-text); border-color: var(--primary); font-weight: 600;
}
.nb-toolbar {
  display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap;
  gap: 8px; padding: 8px 12px; background: var(--bg); border-bottom: 1px solid var(--border);
}
.nb-toolbar button { padding: 5px 10px; font-size: 13px; }
.nb-workspace-layout { display: block; }
.nb-workspace-layout.with-jitsi {
  display: grid; grid-template-columns: 360px 1fr; gap: 0;
}
@media (max-width: 900px) {
  .nb-workspace-layout.with-jitsi { grid-template-columns: 1fr; }
}
.nb-editors-grid {
  flex: 1; min-height: 0;
}
.nb-editors-grid.mode-split {
  display: grid; grid-template-columns: 1fr 1.2fr; border-top: 1px solid var(--border);
}
@media (max-width: 800px) {
  .nb-editors-grid.mode-split { grid-template-columns: 1fr; }
}
.nb-doc-wrap { border-right: 1px solid var(--border); background: var(--card); overflow: auto; min-height: 0; }
.nb-doc-surface {
  min-height: 540px; padding: 18px; outline: none; font-size: 15px; line-height: 1.65;
}
.nb-doc-surface:empty:before {
  content: attr(placeholder); color: var(--muted);
}
.nb-formula {
  display: inline-block; padding: 2px 8px; margin: 0 2px; border-radius: 4px;
  background: rgba(47, 91, 234, 0.1); font-family: "Cambria Math", Georgia, serif; font-weight: 600;
}
.nb-canvas-stage {
  position: relative; flex: 1; min-height: 0; display: flex; overflow: hidden;
}
.nb-canvas-wrap {
  position: relative; width: 100%; height: 100%; min-height: 0; overflow: auto; background: #ffffff; color: #1f2430; outline: none;
}
.nb-canvas-wrap canvas {
  display: block; width: 100%; height: auto; touch-action: none; cursor: crosshair;
}
.nb-bg-grid {
  background-color: #ffffff;
  background-image:
    linear-gradient(to right, rgba(148, 163, 184, 0.28) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(148, 163, 184, 0.28) 1px, transparent 1px);
  background-size: 24px 24px;
}
.nb-bg-lined {
  background-color: #ffffff;
  background-image: linear-gradient(to bottom, rgba(100, 116, 139, 0.28) 1px, transparent 1px);
  background-size: 100% 28px;
}
.nb-bg-blank { background-color: #ffffff; }
.nb-shapes-grid {
  display: grid; gap: 10px; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  margin-top: 8px;
}
.nb-shape-item {
  border: 1px solid var(--border); border-radius: 8px; padding: 8px;
  text-align: center; background: var(--bg); cursor: pointer;
}
.nb-shape-item:hover { border-color: var(--primary); }
.nb-shape-thumb {
  height: 80px; display: flex; align-items: center; justify-content: center;
  background: #ffffff; border-radius: 6px; padding: 4px; overflow: hidden;
}
.nb-shape-thumb svg { max-width: 100%; max-height: 72px; height: auto; }
.nb-modal-backdrop {
  position: fixed; inset: 0; background: rgba(0,0,0,0.65);
  display: flex; align-items: center; justify-content: center; z-index: 50; padding: 16px;
}
.nb-modal-backdrop[hidden] { display: none; }
.nb-modal-card {
  background: var(--card); color: var(--text); padding: 16px;
  border-radius: 10px; max-width: 920px; width: 100%;
}
.nb-text-overlay {
  position: absolute; z-index: 25;
  background: rgba(255, 255, 255, 0.97); color: #1e293b;
  border: 2px solid #2f5bea; border-radius: 8px;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.18);
  padding: 6px; min-width: 280px; max-width: 92%;
}
.nb-text-overlay[hidden] { display: none; }
.nb-text-mini-bar {
  display: flex; flex-wrap: wrap; gap: 4px; align-items: center;
  padding-bottom: 6px; margin-bottom: 6px;
  border-bottom: 1px solid #cbd5e1;
}
.nb-text-mini-bar button {
  padding: 3px 7px; font-size: 12px; line-height: 1.2;
  background: #f8fafc; color: #1e293b; border: 1px solid #cbd5e1; border-radius: 5px;
  cursor: pointer;
}
.nb-text-mini-bar button:hover, .nb-text-mini-bar button.active {
  background: #2f5bea; color: #ffffff; border-color: #2f5bea;
}
.nb-text-mini-bar select {
  width: auto; padding: 2px 6px; font-size: 12px; height: 26px;
  background: #f8fafc; color: #1e293b; border: 1px solid #cbd5e1; border-radius: 5px;
}
.nb-tb-editor {
  min-width: 240px; min-height: 54px; width: 320px;
  padding: 6px 8px; outline: none; resize: both; overflow: auto;
  border: 1px dashed #94a3b8; border-radius: 5px;
  background: #ffffff; color: #1e293b;
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 18px; line-height: 1.4;
}
.nb-tb-editor:empty:before {
  content: attr(placeholder); color: #94a3b8;
}

/* ==========================================================================
   Teacher Studio: Office Ribbon, OneNote Multi-Column & Infinite Canvas UI
   ========================================================================== */

/* Edge-to-Edge Full-Width Mode for Teacher Studio */
body.ts-studio-mode {
  margin: 0 !important;
  padding: 0 !important;
  background: var(--ts-canvas-bg) !important;
  overflow: hidden !important;
}
body.ts-studio-mode #topbar {
  display: none !important;
}
body.ts-studio-mode main {
  max-width: 100% !important;
  width: 100% !important;
  margin: 0 !important;
  padding: 0 !important;
}
body.ts-studio-mode .ts-studio {
  width: 100vw;
  max-width: 100%;
  height: 100dvh;
  margin: 0 !important;
  border-radius: 0 !important;
  border: none !important;
  box-shadow: none !important;
}

/* Γενικές γραμματοσειρές και σκιές Studio */
.ts-studio {
  display: flex; flex-direction: column; width: 100%;
  background: var(--card); border: 1px solid var(--border);
  border-radius: 10px; overflow: hidden; margin-bottom: 24px;
  box-shadow: 0 4px 18px rgba(0, 0, 0, 0.05);
}

/* 1. Header Bar Τετραδίου */
.ts-header {
  display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center;
  padding: 8px 16px; background: #0B66C3; color: #ffffff; gap: 10px; min-height: 44px;
  flex-shrink: 0;
}
.ts-header a.ts-back {
  color: #ffffff; text-decoration: none; font-size: 13px; font-weight: 500; opacity: 0.9;
}
.ts-header a.ts-back:hover { opacity: 1; text-decoration: underline; }
.ts-header .ts-title-box { display: flex; align-items: center; gap: 10px; }
.ts-header h1.ts-title { margin: 0; font-size: 16px; font-weight: 700; color: #ffffff; }
.ts-header .ts-sync-badge {
  font-size: 12px; background: rgba(255, 255, 255, 0.18);
  padding: 2px 10px; border-radius: 99px; display: inline-flex; align-items: center; gap: 6px;
}
.ts-access-panel-wrap {
  padding: 12px 16px; background: var(--bg); flex-shrink: 0; max-height: 40vh; overflow: auto;
}

.ts-tool-btn {
  padding: 5px 10px; font-size: 12px; font-weight: 500;
  border: 1px solid var(--border); border-radius: 6px;
  background: var(--card); color: var(--text); cursor: pointer;
  display: inline-flex; align-items: center; gap: 5px;
}
.ts-tool-btn:hover { border-color: var(--ts-accent); }
.ts-tool-btn.active {
  background: var(--ts-accent-soft); border-color: var(--ts-accent); color: var(--ts-accent); font-weight: 600;
}
.ts-color-swatches { display: flex; gap: 5px; align-items: center; }
.ts-color-swatch {
  width: 28px; height: 28px; border-radius: 50%; border: 1px solid rgba(0,0,0,0.15);
  cursor: pointer; padding: 0; outline: none;
}
.ts-color-swatch.active {
  box-shadow: 0 0 0 2px var(--ts-surface), 0 0 0 4px var(--ts-accent);
}

/* Minimalist Single-Row Icon Toolbar & Dropdown Menus */
.ts-icon-toolbar {
  display: flex; align-items: center; gap: 6px;
  padding: 6px 14px; background: var(--card);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
  position: relative; z-index: 100; min-height: 48px; box-sizing: border-box;
  flex-shrink: 0;
}
.ts-tb-group { display: inline-flex; align-items: center; gap: 4px; }
.ts-tb-sep { display: inline-block; width: 1px; height: 24px; background: var(--border); margin: 0 4px; }
.ts-icon-btn {
  width: 40px; height: 40px; border-radius: 6px; border: 1px solid transparent;
  background: transparent; color: var(--text); display: inline-flex;
  align-items: center; justify-content: center; font-size: 14px;
  cursor: pointer; transition: all 0.12s ease;
}
.ts-icon-btn:hover { background: var(--bg); border-color: var(--border); color: var(--ts-accent); }
.ts-icon-btn.active { background: var(--ts-accent-soft); border-color: var(--ts-accent); color: var(--ts-accent); }
.ts-size-btn {
  width: 40px; height: 40px; border-radius: 6px; border: 1px solid var(--border);
  background: var(--bg); color: var(--text); cursor: pointer;
  display: inline-flex; align-items: center; justify-content: center;
  transition: all 0.12s ease; padding: 0;
}
.ts-size-btn:hover { border-color: var(--ts-accent); background: var(--card); }
.ts-size-btn.active {
  background: var(--ts-accent-soft); border-color: var(--ts-accent);
}
.ts-size-dot {
  display: inline-block; border-radius: 50%; background: currentColor;
}
.ts-size-dot.s-sm { width: 6px; height: 6px; }
.ts-size-dot.s-md { width: 10px; height: 10px; }
.ts-size-dot.s-lg { width: 14px; height: 14px; }
.ts-size-wrap {
  display: inline-flex; align-items: center; position: relative; margin-left: 2px;
}
.ts-size-input {
  width: 56px; height: 40px; padding: 2px 22px 2px 8px; font-size: 12px; font-weight: 600;
  border: 1px solid var(--border); border-radius: 6px; background: var(--bg); color: var(--text);
  text-align: right; box-sizing: border-box;
}
.ts-size-input:focus {
  outline: 2px solid var(--ts-accent); outline-offset: 1px; border-color: var(--ts-accent);
}
.ts-size-unit {
  position: absolute; right: 6px; font-size: 12px; color: var(--muted); pointer-events: none; font-weight: 500;
}
.ts-color-picker-input {
  width: 24px; height: 24px; padding: 0; border: 1px solid var(--border);
  border-radius: 50%; cursor: pointer; background: none;
}
.ts-dropdown { position: relative; }
.ts-dropdown-btn {
  height: 40px; padding: 0 12px; border-radius: 6px; border: 1px solid var(--border);
  background: var(--bg); color: var(--text); font-size: 12px; font-weight: 500;
  cursor: pointer; display: inline-flex; align-items: center; gap: 6px;
  transition: all 0.12s ease;
}
.ts-dropdown-btn:hover { border-color: var(--ts-accent); background: var(--card); }
.ts-dd-arrow { font-size: 12px; opacity: 0.7; }
.ts-dropdown-menu {
  position: absolute; top: calc(100% + 6px); left: 0; min-width: 220px;
  background: var(--card); border: 1px solid var(--border); border-radius: 8px;
  box-shadow: 0 10px 25px -5px rgba(0,0,0,0.15), 0 8px 10px -6px rgba(0,0,0,0.1);
  padding: 6px 0; z-index: 1000; display: flex; flex-direction: column;
}
.ts-dropdown-menu[hidden] { display: none !important; }
.ts-dd-title {
  padding: 6px 12px 4px; font-size: 12px; font-weight: 700;
  text-transform: uppercase; color: var(--muted); letter-spacing: 0.05em;
}
.ts-dd-item {
  display: flex; align-items: center; gap: 9px; width: 100%;
  padding: 7px 12px; border: none; background: transparent;
  color: var(--text); font-size: 13px; text-align: left; cursor: pointer;
  transition: background 0.1s ease;
}
.ts-dd-item:hover { background: var(--ts-hover); color: var(--ts-accent); }
.ts-dd-item.active { background: var(--ts-accent-soft); color: var(--ts-accent); font-weight: 600; }
.ts-dd-divider { height: 1px; background: var(--border); margin: 4px 0; }
.ts-dd-label {
  display: flex; align-items: center; gap: 8px; padding: 6px 12px;
  font-size: 12px; font-weight: 500; color: var(--text); cursor: pointer;
}
.ts-dd-label:hover { background: var(--ts-hover); }

/* Accessibility Focus Rings */
.ts-icon-btn:focus-visible,
.ts-tool-btn:focus-visible,
.ts-dropdown-btn:focus-visible,
.ts-dd-item:focus-visible,
.ts-item-btn:focus-visible,
.ts-dock-tab:focus-visible,
.ts-size-btn:focus-visible,
.ts-color-swatch:focus-visible,
.nb-selection-bar-btn:focus-visible {
  outline: 2px solid var(--ts-accent);
  outline-offset: 2px;
}

/* Floating Selection Bar for Geometric Objects */
.nb-selection-bar {
  position: absolute;
  top: 12px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 50;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 4px 8px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
}
.nb-selection-bar[hidden] {
  display: none !important;
}
.nb-selection-bar-btn {
  width: 32px;
  height: 32px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  transition: all 0.12s ease;
  padding: 0;
}
.nb-selection-bar-btn:hover {
  border-color: var(--ts-accent);
  background: var(--card);
  color: var(--ts-accent);
}
.nb-selection-bar-btn.active {
  background: var(--ts-accent-soft);
  border-color: var(--ts-accent);
  color: var(--ts-accent);
}
.nb-selection-bar-btn.danger {
  color: var(--bad, #dc2626);
}
.nb-selection-bar-btn.danger:hover {
  background: #fee2e2;
  border-color: #dc2626;
}
.nb-selection-bar-sep {
  display: inline-block;
  width: 1px;
  height: 20px;
  background: var(--border);
  margin: 0 2px;
}

/* Sidebar collapse support */
.ts-columns-layout.sidebar-collapsed .ts-col-dock,
.ts-columns-layout.sidebar-collapsed .ts-col-notebooks,
.ts-columns-layout.sidebar-collapsed .ts-col-sections,
.ts-columns-layout.sidebar-collapsed .ts-resizer {
  display: none !important;
}

/* 3. OneNote Multi-Column Workspace & Splitters */
.ts-columns-layout {
  display: flex; width: 100%; flex: 1; min-height: 420px;
  position: relative; overflow: hidden;
}
.ts-col-dock {
  background: var(--bg); border-right: 1px solid var(--border);
  width: 260px; min-width: 200px; max-width: 380px; flex-shrink: 0;
  display: flex; flex-direction: column; overflow: auto;
}
.ts-col-dock.collapsed { display: none !important; }
.ts-dock-tabs {
  display: flex; border-bottom: 1px solid var(--border); background: var(--card);
}
.ts-dock-tab {
  flex: 1; padding: 8px 4px; font-size: 12px; text-align: center;
  border: none; border-bottom: 2px solid transparent; background: transparent;
  cursor: pointer; font-weight: 600; color: var(--muted);
}
.ts-dock-tab.active {
  color: var(--ts-accent); border-bottom-color: var(--ts-accent); background: var(--bg);
}
.ts-col-notebooks {
  background: var(--ts-surface-2); border-right: 1px solid var(--border);
  width: 200px; min-width: 130px; max-width: 280px; flex-shrink: 0;
  display: flex; flex-direction: column; overflow: auto;
}
.ts-col-sections {
  background: var(--ts-surface); border-right: 1px solid var(--border);
  width: 210px; min-width: 160px; max-width: 320px; flex-shrink: 0;
  display: flex; flex-direction: column; overflow: auto;
}
.ts-col-canvas {
  flex: 1; min-width: 320px; min-height: 0; background: var(--ts-canvas-bg);
  display: flex; flex-direction: column; position: relative; overflow: hidden;
}
.ts-col-shapes {
  background: var(--ts-surface); border-left: 1px solid var(--border);
  width: 320px; min-width: 270px; max-width: 440px; flex-shrink: 0;
  display: flex; flex-direction: column; overflow-y: auto; z-index: 15;
}
.ts-shapes-header {
  padding: 10px 14px; font-size: 13px; font-weight: 700;
  display: flex; justify-content: space-between; align-items: center;
  border-bottom: 1px solid var(--border); background: var(--bg);
}
.ts-shape-btn-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 8px; padding: 10px 14px;
}
.ts-shape-tool-btn {
  padding: 8px 6px; font-size: 12px; font-weight: 600; text-align: center;
  border: 1px solid var(--border); background: var(--bg); border-radius: 6px;
  cursor: pointer; transition: all 0.15s ease; color: var(--text);
}
.ts-shape-tool-btn:hover { border-color: var(--ts-accent); background: var(--ts-accent-soft); }
.ts-shape-tool-btn.active {
  background: var(--ts-accent); color: var(--ts-surface); border-color: var(--ts-accent);
}
.ts-shapes-subhead {
  padding: 10px 14px 4px; font-size: 12px; font-weight: 700;
  text-transform: uppercase; color: var(--muted); letter-spacing: 0.05em;
}

/* Resizer Splitter Drag Bars */
.ts-resizer {
  width: 5px; flex-shrink: 0; background: transparent; cursor: col-resize;
  position: relative; transition: background 0.15s ease; z-index: 10;
}
.ts-resizer:hover, .ts-resizer.dragging {
  background: rgba(15, 108, 189, 0.35);
}
.ts-resizer-grip {
  position: absolute; top: 50%; left: 0; transform: translateY(-50%);
  width: 5px; height: 32px; border-radius: 3px; background: rgba(15, 108, 189, 0.4);
}

/* OneNote Column Headers & Items */
.ts-column-header {
  padding: 10px 12px; font-size: 12px; font-weight: 700;
  text-transform: uppercase; color: var(--muted); letter-spacing: 0.05em;
  display: flex; justify-content: space-between; align-items: center;
  border-bottom: 1px solid var(--border);
}
.ts-item-btn {
  display: block; width: 100%; text-align: left; padding: 8px 12px;
  background: transparent; border: none; font-size: 13px; font-weight: 500;
  color: var(--text); cursor: pointer; border-radius: 0;
}
.ts-item-btn:hover { background: rgba(0,0,0,0.04); }
.ts-item-btn.active {
  background: var(--ts-accent-soft); color: var(--ts-accent); font-weight: 600;
}
.ts-section-item {
  border-left: 4px solid #2f5bea; margin: 2px 0;
}
.ts-page-item {
  padding-left: 20px; font-size: 12px;
}
.ts-bottom-action {
  margin-top: auto; padding: 10px; border-top: 1px solid var(--border);
}

/* 4. Infinite Canvas Page Header & Floating Call */
.ts-page-header {
  padding: 14px 20px 8px; border-bottom: 1px solid var(--border); background: var(--ts-surface);
  flex-shrink: 0;
}
.ts-page-title {
  margin: 0 0 4px; font-size: 19px; font-weight: 700; color: #1e293b;
}
.ts-page-meta {
  font-size: 12px; color: var(--muted);
}
.ts-expand-controls {
  display: flex; justify-content: center; align-items: center; gap: 8px;
  padding: 6px 14px 10px; background: var(--ts-surface); border-top: 1px dashed var(--border);
  flex-shrink: 0;
}
.ts-expand-btn {
  padding: 7px 18px; border-radius: 99px; font-size: 13px; font-weight: 600;
  border: 1px solid var(--ts-accent); background: var(--ts-accent-soft); color: var(--ts-accent); cursor: pointer;
  box-shadow: 0 2px 6px rgba(15, 108, 189, 0.12);
}
.ts-expand-btn:hover { background: var(--ts-accent); color: var(--ts-surface); }

/* Floating Jitsi Live Video Widget */
.ts-floating-jitsi {
  position: absolute; top: 16px; right: 20px; z-index: 30;
  width: 290px; background: #18181b; color: #ffffff;
  border-radius: 10px; box-shadow: 0 10px 28px rgba(0,0,0,0.3);
  border: 1px solid #3f3f46; overflow: hidden;
}
.ts-jitsi-head {
  display: flex; justify-content: space-between; align-items: center;
  padding: 6px 10px; background: #27272a; font-size: 11px; font-weight: 600;
}
.ts-jitsi-video-container {
  width: 100%; height: 160px; background: #000000; position: relative;
}
.ts-jitsi-controls {
  display: flex; justify-content: space-around; padding: 6px; background: #18181b;
}
.ts-jitsi-controls button {
  padding: 4px 8px; font-size: 11px; border-radius: 4px; border: none;
  background: #27272a; color: #ffffff; cursor: pointer;
}
.ts-jitsi-controls button.danger { background: #c62828; }

/* Responsive Layout for Compact Screens */
@media (max-width: 1100px) {
  .ts-col-dock,
  .ts-col-notebooks {
    display: none !important;
  }
  .ts-col-shapes {
    width: 260px !important;
  }
}

/* ==========================================================================
   Teacher Dashboard: Command Center, Messages Hub & Schedule Grid
   ========================================================================== */

/* Full Width Dynamic Workspace Mode */
body:has(.db-container) main,
main:has(.db-container),
body.db-wide-mode main {
  max-width: 100% !important;
  width: 100% !important;
  padding: 14px 24px !important;
  box-sizing: border-box;
}

.db-container {
  display: flex; flex-direction: column; width: 100%; max-width: 100%; margin: 0; gap: 16px;
}
.db-hero-banner {
  display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center;
  background: linear-gradient(135deg, #0B66C3 0%, #1D4ED8 100%); color: #ffffff;
  padding: 16px 24px; border-radius: 12px; box-shadow: 0 4px 14px rgba(11, 102, 195, 0.2); gap: 14px;
}
.db-hero-banner .db-banner-label {
  font-size: 11px; font-weight: 700; color: #BAE6FD; letter-spacing: 0.05em; text-transform: uppercase;
}
.db-hero-banner .db-banner-title {
  font-size: 17px; font-weight: 700; color: #ffffff; margin-top: 4px;
}
.db-hero-banner .db-banner-actions {
  display: flex; gap: 10px; align-items: center; flex-wrap: wrap;
}
.db-btn-studio {
  background: #ffffff; color: #0B66C3 !important; font-weight: 700; font-size: 13px;
  padding: 8px 18px; border-radius: 8px; border: none; cursor: pointer; text-decoration: none;
  display: inline-flex; align-items: center; gap: 6px; box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}
.db-btn-studio:hover { background: #F8FAFC; }
.db-btn-ghost {
  background: rgba(255, 255, 255, 0.15); color: #ffffff !important; font-weight: 600; font-size: 12px;
  padding: 8px 14px; border-radius: 8px; border: 1px solid rgba(255, 255, 255, 0.3); text-decoration: none;
  cursor: pointer; display: inline-flex; align-items: center; gap: 6px;
}
.db-btn-ghost:hover { background: rgba(255, 255, 255, 0.25); }

/* Modular Dynamic Dashboard Layout (1, 2, or 3 columns) */
.db-grid {
  display: grid; gap: 18px; align-items: start; transition: all 0.2s ease;
}
.db-grid[data-cols="1"] {
  grid-template-columns: minmax(320px, 920px); justify-content: center;
}
.db-grid[data-cols="2"] {
  grid-template-columns: repeat(2, minmax(320px, 1fr));
}
.db-grid[data-cols="3"], .db-grid:not([data-cols]) {
  grid-template-columns: repeat(3, minmax(300px, 1fr));
}
@media (max-width: 1024px) {
  .db-grid[data-cols="2"], .db-grid[data-cols="3"] {
    grid-template-columns: 1fr;
  }
}
.db-col {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 18px; display: flex; flex-direction: column; gap: 12px; min-height: 580px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}
.db-col-header {
  display: flex; justify-content: space-between; align-items: center;
  padding-bottom: 8px; border-bottom: 1px solid var(--border);
}
.db-col-header h2 { margin: 0; font-size: 15px; font-weight: 700; color: var(--text); display: flex; align-items: center; gap: 6px; }
.db-col-controls {
  display: flex; align-items: center; gap: 4px;
}
.db-col-btn {
  background: var(--bg); border: 1px solid var(--border); border-radius: 6px;
  padding: 3px 7px; font-size: 11px; color: var(--muted); cursor: pointer;
  display: inline-flex; align-items: center; justify-content: center;
  transition: all 0.15s ease;
}
.db-col-btn:hover {
  background: var(--card); color: #0B66C3; border-color: #0B66C3;
}
.db-col-btn.close:hover {
  color: #DC2626; border-color: #DC2626; background: #FEF2F2;
}
.db-item-card {
  background: #F8FAFC; border: 1px solid var(--border); border-radius: 10px;
  padding: 12px 14px; display: flex; flex-direction: column; gap: 6px; transition: border-color 0.15s ease;
}
.db-item-card:hover { border-color: #0B66C3; }
.db-item-card.has-changes {
  border-color: #0B66C3; background: #EFF6FC;
}
.db-item-head {
  display: flex; justify-content: space-between; align-items: center; gap: 8px;
}
.db-item-title { font-size: 14px; font-weight: 700; color: #0F172A; }
.db-item-sub { font-size: 12px; color: var(--muted); }
.db-item-meta { font-size: 11px; color: #94A3B8; }

/* Filter Tabs & Toggle */
.db-filter-bar {
  display: flex; gap: 4px; background: var(--bg); padding: 4px; border-radius: 8px;
}
.db-filter-btn {
  padding: 5px 10px; font-size: 11px; font-weight: 600; border-radius: 6px; border: none;
  background: transparent; color: var(--muted); cursor: pointer;
}
.db-filter-btn.active {
  background: var(--card); color: #0B66C3; font-weight: 700; box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}
.db-toggle-btn {
  font-size: 11px; font-weight: 700; padding: 3px 10px; border-radius: 99px;
  border: 1px solid #0B66C3; background: #EFF6FC; color: #0B66C3; cursor: pointer;
}
.db-toggle-btn.off {
  border-color: var(--border); background: var(--bg); color: var(--muted);
}

/* Messages Center */
.db-msg-card {
  display: flex; gap: 12px; align-items: flex-start; padding: 12px;
  background: #F8FAFC; border: 1px solid var(--border); border-radius: 10px;
}
.db-msg-card.unread { background: #EFF6FC; border-color: #BFDBFE; }
.db-avatar {
  width: 36px; height: 36px; border-radius: 50%; color: #ffffff;
  display: flex; align-items: center; justify-content: center; font-size: 12px; font-weight: 700; flex-shrink: 0;
}
.db-msg-content { flex: 1; display: flex; flex-direction: column; gap: 3px; min-width: 0; }
.db-msg-head { display: flex; justify-content: space-between; align-items: center; gap: 6px; }
.db-msg-name { font-size: 13px; font-weight: 700; color: #0F172A; }
.db-msg-time { font-size: 11px; color: #94A3B8; }
.db-msg-snippet {
  font-size: 12px; color: #334155; white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}

/* In-Dashboard Column Controller Toolbar (Inverted Layout) */
.db-toolbar-bar {
  display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px;
  background: var(--card); border: 1px solid var(--border); border-radius: 10px;
  padding: 10px 16px; margin-bottom: 2px; box-shadow: 0 1px 3px rgba(0,0,0,0.03);
}
.db-toolbar-left {
  display: flex; align-items: center; gap: 8px; flex-wrap: wrap;
}
.db-toolbar-label {
  font-size: 12px; font-weight: 700; color: var(--muted); margin-right: 4px; display: inline-flex; align-items: center; gap: 4px;
}
.db-col-toggle-btn {
  background: #ffffff; border: 1px solid var(--border); border-radius: 8px;
  padding: 5px 12px; font-size: 12px; font-weight: 600; color: #475569;
  cursor: pointer; display: inline-flex; align-items: center; gap: 6px;
  transition: all 0.15s ease;
}
.db-col-toggle-btn:hover {
  background: #F8FAFC; border-color: #0B66C3; color: #0B66C3;
}
.db-col-toggle-btn.active {
  background: #EFF6FC; border-color: #0B66C3; color: #0B66C3; font-weight: 700;
  box-shadow: 0 1px 3px rgba(11, 102, 195, 0.12);
}
.db-col-toggle-btn .chk {
  background: #0B66C3; color: #ffffff; font-size: 9px; width: 14px; height: 14px;
  border-radius: 50%; display: inline-flex; align-items: center; justify-content: center;
}
.db-toolbar-right {
  display: flex; align-items: center; gap: 8px; text-align: right;
}
.db-greeting-name {
  font-size: 14px; font-weight: 700; color: #0F172A;
}
.db-greeting-date {
  font-size: 12px; color: var(--muted);
}