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

:root {
  --bg-primary: #f5f5f5;
  --bg-secondary: #ffffff;
  --bg-toolbar: #2c3e50;
  --text-primary: #333333;
  --text-secondary: #666666;
  --text-light: #ffffff;
  --accent: #3498db;
  --accent-hover: #2980b9;
  --danger: #e74c3c;
  --danger-hover: #c0392b;
  --border: #e0e0e0;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background-color: var(--bg-primary);
  overflow: hidden;
  height: 100vh;
}

.app {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.session-id {
  font-size: 0.875rem;
  color: var(--text-secondary);
  background-color: var(--bg-primary);
  padding: 0.25rem 0.75rem;
  border-radius: 4px;
  font-family: monospace;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.user-count {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.btn {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: 6px;
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-share {
  background-color: var(--accent);
  color: var(--text-light);
}

.btn-share:hover {
  background-color: var(--accent-hover);
}

.btn-primary {
  background-color: var(--accent);
  color: var(--text-light);
}

.btn-primary:hover {
  background-color: var(--accent-hover);
}

.btn-cancel {
  background-color: var(--bg-primary);
  color: var(--text-primary);
}

.btn-cancel:hover {
  background-color: var(--border);
}

.btn-danger {
  background-color: var(--danger);
  color: var(--text-light);
}

.btn-danger:hover {
  background-color: var(--danger-hover);
}

/* Header with dual toolbar rows */
.header {
  display: flex;
  flex-direction: column;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow);
  z-index: 100;
}

/* Toolbar rows */
.toolbar-row {
  display: flex;
  align-items: center;
  padding: 0.5rem 1rem;
  gap: 0.5rem;
}

.primary-toolbar {
  border-bottom: 1px solid var(--border);
}

.options-bar {
  background-color: var(--bg-primary);
  padding: 0.375rem 1rem;
}

/* Toolbar groups */
.toolbar-group {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.toolbar-group.brand {
  gap: 0.75rem;
}

/* Dividers and spacers */
.toolbar-divider {
  width: 1px;
  height: 24px;
  background-color: var(--border);
  margin: 0 0.5rem;
}

.toolbar-spacer {
  flex: 1;
}

/* Tool buttons (horizontal layout) */
.tool-btn {
  width: 36px;
  height: 36px;
  border: none;
  border-radius: 6px;
  background-color: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
}

.tool-btn svg {
  width: 20px;
  height: 20px;
}

.tool-btn:hover {
  background-color: var(--bg-primary);
  color: var(--text-primary);
}

.tool-btn.active {
  background-color: var(--accent);
  color: var(--text-light);
}

.tool-btn.danger:hover {
  background-color: var(--danger);
  color: var(--text-light);
}

.tool-btn.disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.tool-btn.disabled:hover {
  background-color: transparent;
  color: var(--text-secondary);
}

/* Option labels */
.option-label {
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-right: 0.5rem;
  font-weight: 500;
}

/* Color palette (horizontal) */
.color-palette {
  display: flex;
  gap: 4px;
}

.color-btn {
  width: 22px;
  height: 22px;
  border: 2px solid transparent;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.15s;
}

.color-btn:hover {
  transform: scale(1.15);
}

.color-btn.active {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.3);
}

/* Stroke options (horizontal) */
.stroke-options {
  display: flex;
  gap: 4px;
}

.stroke-btn {
  width: 40px;
  height: 28px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background-color: var(--bg-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 6px;
  transition: all 0.15s;
}

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

.stroke-btn.active {
  border-color: var(--accent);
  background-color: rgba(52, 152, 219, 0.1);
}

.stroke-preview {
  width: 100%;
  background-color: var(--text-primary);
  border-radius: 2px;
}

/* Arrow style options (horizontal) */
.arrow-style-options {
  display: flex;
  gap: 4px;
}

.arrow-style-btn {
  width: 36px;
  height: 28px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
}

.arrow-style-btn svg {
  width: 18px;
  height: 18px;
}

.arrow-style-btn:hover {
  border-color: var(--accent);
  color: var(--text-primary);
}

.arrow-style-btn.active {
  border-color: var(--accent);
  background-color: rgba(52, 152, 219, 0.1);
  color: var(--accent);
}

/* Contextual options - hidden by default */
.context-options {
  display: none;
}

.context-options.visible {
  display: flex;
}

/* Zoom level */
.zoom-level {
  font-size: 0.75rem;
  color: var(--text-secondary);
  min-width: 45px;
  text-align: center;
}

/* Main content - full width without sidebar */
.main {
  display: flex;
  flex: 1;
  overflow: hidden;
}

.canvas-container {
  flex: 1;
  width: 100%;
  position: relative;
  overflow: hidden;
  background-color: var(--bg-secondary);
  background-image: 
    linear-gradient(rgba(0, 0, 0, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 0, 0, 0.03) 1px, transparent 1px);
  background-size: 20px 20px;
}

#whiteboard {
  position: absolute;
  top: 0;
  left: 0;
  cursor: crosshair;
}

/* Modals */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 1000;
  align-items: center;
  justify-content: center;
}

.modal.active {
  display: flex;
}

.modal-content {
  background-color: var(--bg-secondary);
  padding: 1.5rem;
  border-radius: 12px;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
  max-width: 400px;
  width: 90%;
}

.modal-content h3 {
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.modal-content p {
  margin-bottom: 1.5rem;
  color: var(--text-secondary);
}

.modal-content textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.875rem;
  resize: vertical;
  margin-bottom: 1rem;
  font-family: inherit;
}

.modal-content textarea:focus {
  outline: none;
  border-color: var(--accent);
}

.modal-content .text-input {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 1rem;
  margin-bottom: 1rem;
  font-family: inherit;
}

.modal-content .text-input:focus {
  outline: none;
  border-color: var(--accent);
}

.font-size-selector {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.font-size-selector label {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.font-size-selector select {
  flex: 1;
  padding: 0.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.875rem;
  background-color: var(--bg-secondary);
  cursor: pointer;
}

.font-size-selector select:focus {
  outline: none;
  border-color: var(--accent);
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
}

/* Toast notification */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background-color: var(--bg-toolbar);
  color: var(--text-light);
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
  opacity: 0;
  transition: all 0.3s;
  z-index: 1001;
}

.toast.active {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* Sticky notes on canvas */
.sticky-note {
  position: absolute;
  min-width: 150px;
  min-height: 100px;
  padding: 10px;
  background-color: #fff9c4;
  border: 1px solid #f0e68c;
  border-radius: 4px;
  box-shadow: 2px 2px 8px rgba(0, 0, 0, 0.1);
  font-size: 14px;
  word-wrap: break-word;
  cursor: move;
  user-select: none;
}

.sticky-note:hover {
  box-shadow: 4px 4px 12px rgba(0, 0, 0, 0.15);
}

/* Eraser cursor */
.canvas-container.eraser-mode #whiteboard {
  cursor: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="black" stroke-width="2"><path d="M20 20H7L3 16c-.8-.8-.8-2 0-2.8L14.8 1.4c.8-.8 2-.8 2.8 0l5 5c.8.8.8 2 0 2.8L11 20"/></svg>') 12 12, crosshair;
}

/* Select mode cursor */
.canvas-container.select-mode #whiteboard {
  cursor: default;
}

.canvas-container.select-mode.dragging #whiteboard {
  cursor: move;
}

/* Pan mode cursor */
.canvas-container.pan-mode,
.canvas-container.pan-mode #whiteboard {
  cursor: grab;
}

.canvas-container.pan-mode.panning,
.canvas-container.pan-mode.panning #whiteboard,
.canvas-container.panning,
.canvas-container.panning #whiteboard {
  cursor: grabbing;
}

/* Resize cursor */
.canvas-container.resizing #whiteboard {
  cursor: nwse-resize;
}

/* Responsive adjustments */
@media (max-width: 768px) {
  .toolbar-row {
    padding: 0.375rem 0.5rem;
    flex-wrap: wrap;
  }
  
  .toolbar-group.brand .logo {
    font-size: 1rem;
  }
  
  .session-id {
    display: none;
  }
  
  .tool-btn {
    width: 32px;
    height: 32px;
  }
  
  .tool-btn svg {
    width: 18px;
    height: 18px;
  }
  
  .option-label {
    display: none;
  }
  
  .toolbar-divider {
    height: 20px;
  }
}

@media (max-width: 480px) {
  .options-bar {
    overflow-x: auto;
    flex-wrap: nowrap;
  }
  
  .toolbar-group.export {
    display: none;
  }
  
  .toolbar-group.zoom .tool-btn:not(#zoomInBtn):not(#zoomOutBtn) {
    display: none;
  }
}