.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: var(--sidebar-width);
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: var(--space-4) 0;
  z-index: 100;
}

.sidebar-logo {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-6);
}

.sidebar-nav {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.sidebar-nav ul {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.nav-item {
  position: relative;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--text-tertiary);
  transition: all var(--transition-fast);
}

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

.nav-item.active {
  background: var(--brand-gradient);
  color: #fff;
}

.nav-tooltip {
  position: absolute;
  left: calc(100% + 12px);
  top: 50%;
  transform: translateY(-50%);
  background: var(--text-primary);
  color: var(--bg-surface);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-fast);
  z-index: 200;
}

.nav-item:hover .nav-tooltip {
  opacity: 1;
}

.sidebar-bottom {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding-top: var(--space-4);
  border-top: 1px solid var(--border-color);
}

@media (max-width: 780px) {
  .sidebar {
    transform: translateX(-100%);
    transition: transform var(--transition-base);
  }
  .sidebar.open {
    transform: translateX(0);
  }
}