/* App Shell */
.app-shell {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* Toolbar */
.toolbar {
  display: flex;
  align-items: center;
  height: var(--toolbar-height);
  padding: 0 var(--space-4);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  z-index: var(--z-toolbar);
  gap: var(--space-3);
  flex-shrink: 0;
}

.toolbar-left {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex: 1;
  min-width: 0;
}

.toolbar-center {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.toolbar-right {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.project-name {
  font-size: 15px;
  font-weight: 600;
  border: 1px solid transparent;
  border-radius: 4px;
  padding: 2px 6px;
  background: transparent;
  min-width: 120px;
  max-width: 300px;
  transition: all var(--transition-fast);
}

.project-name:hover {
  border-color: var(--color-border);
}

.project-name:focus {
  border-color: var(--color-accent);
  background: var(--color-surface);
  box-shadow: 0 0 0 3px var(--color-accent-light);
  outline: none;
}

/* Zoom Controls */
.zoom-controls {
  display: flex;
  background: var(--color-bg);
  border-radius: 8px;
  padding: 2px;
  gap: 1px;
}

.zoom-btn {
  padding: 4px 10px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.zoom-btn:hover {
  color: var(--color-text-primary);
  background: var(--color-surface);
}

.zoom-btn.active {
  background: var(--color-surface);
  color: var(--color-text-primary);
  box-shadow: var(--shadow-sm);
}

/* Toolbar buttons */
.toolbar-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 6px;
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

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

.toolbar-btn-text {
  width: auto;
  padding: 0 var(--space-2);
  font-size: 12px;
  font-weight: 500;
}

/* Main content area */
.main-content {
  display: flex;
  flex: 1;
  overflow: hidden;
  position: relative;
}

/* Task list sidebar */
.task-list-panel {
  width: var(--task-list-width);
  min-width: 200px;
  max-width: 500px;
  display: flex;
  flex-direction: column;
  border-right: 1px solid var(--color-border);
  background: var(--color-surface);
  flex-shrink: 0;
  position: relative;
}

.task-list-header {
  display: flex;
  align-items: center;
  height: var(--timeline-header-height);
  min-height: var(--timeline-header-height);
  padding: 0 var(--space-3);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
  font-weight: 600;
  font-size: 12px;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  flex-shrink: 0;
}

.task-list-body {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
}

.task-list-footer {
  flex-shrink: 0;
  border-top: 1px solid var(--color-border);
}

/* Resize handle for task list */
.task-list-resize {
  position: absolute;
  right: -3px;
  top: 0;
  bottom: 0;
  width: 6px;
  cursor: col-resize;
  z-index: 10;
}

.task-list-resize:hover,
.task-list-resize.active {
  background: var(--color-accent);
  opacity: 0.3;
}

/* Timeline panel */
.timeline-panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  position: relative;
}

.timeline-header {
  height: var(--timeline-header-height);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
  overflow: hidden;
  flex-shrink: 0;
  position: sticky;
  top: 0;
  z-index: var(--z-header);
}

.timeline-body {
  flex: 1;
  overflow: auto;
  position: relative;
}

/* Empty state */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  padding: var(--space-8);
  text-align: center;
  color: var(--color-text-secondary);
}

.empty-state-icon {
  font-size: 48px;
  margin-bottom: var(--space-4);
  opacity: 0.3;
}

.empty-state-title {
  font-size: 17px;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--space-2);
}

.empty-state-text {
  font-size: 13px;
  max-width: 320px;
  line-height: 1.5;
  margin-bottom: var(--space-6);
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--color-accent);
  color: white;
  border-radius: 8px;
  font-size: 13px;
  font-weight: 500;
  transition: background var(--transition-fast);
}

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

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--color-bg);
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 13px;
  font-weight: 500;
  transition: all var(--transition-fast);
}

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

/* Save indicator */
.save-indicator {
  font-size: 11px;
  color: var(--color-text-tertiary);
  opacity: 0;
  transition: opacity var(--transition-normal);
}

.save-indicator.visible {
  opacity: 1;
}