.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  height: 100vh;
  width: var(--sidebar-width);
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  z-index: 100;
  transition: width var(--transition-base), transform var(--transition-base);
  overflow: hidden;
  will-change: transform;
  backface-visibility: hidden;
}

.sidebar.collapsed {
  width: var(--sidebar-collapsed);
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px;
  height: var(--header-height);
  border-bottom: 1px solid var(--border-color);
  flex-shrink: 0;
}

.sidebar-logo {
  height: 32px;
  transition: opacity var(--transition-fast);
}

.collapsed .sidebar-logo {
  opacity: 0;
  width: 0;
}

.sidebar-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.sidebar-toggle:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.collapsed .sidebar-toggle {
  margin: 0 auto;
}

.collapsed .sidebar-toggle svg {
  transform: rotate(180deg);
}

.sidebar-nav {
  flex: 1;
  padding: 12px 8px;
  display: flex;
  flex-direction: column;
  gap: 2px;
  overflow-y: auto;
}

.sidebar-section-label {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-tertiary);
  padding: 12px 12px 6px;
  transition: opacity var(--transition-fast);
}

.collapsed .sidebar-section-label {
  opacity: 0;
  height: 0;
  padding: 0;
  overflow: hidden;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 12px;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  text-decoration: none;
  transition: all var(--transition-fast);
  position: relative;
  white-space: nowrap;
}

.nav-item:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.nav-item.active {
  background: var(--accent-light);
  color: var(--accent);
}

.nav-item.active::before {
  content: '';
  position: absolute;
  left: -8px;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 20px;
  background: var(--accent);
  border-radius: 0 3px 3px 0;
}

.nav-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

.nav-text {
  flex: 1;
  font-size: 14px;
  font-weight: 500;
  transition: opacity var(--transition-fast);
}

.collapsed .nav-text {
  opacity: 0;
  width: 0;
  overflow: hidden;
}

.nav-badge {
  font-size: 11px;
  font-weight: 600;
  background: var(--accent);
  color: white;
  padding: 2px 7px;
  border-radius: 10px;
  min-width: 20px;
  text-align: center;
  transition: opacity var(--transition-fast);
}

.collapsed .nav-badge {
  opacity: 0;
}

.sidebar-footer {
  padding: 8px;
  border-top: 1px solid var(--border-color);
  flex-shrink: 0;
}