.lab-shell {
  display: grid;
  grid-template-columns: 188px minmax(0, 1fr);
  min-height: calc(100vh - 64px);
}

.lab-sidebar {
  border-right: 1px solid var(--border-soft);
  background: var(--bg-soft);
}

.lab-sidebar-inner {
  position: sticky;
  top: 63px;
  padding: 32px 20px;
}

.lab-label {
  margin: 0 10px 12px;
  color: var(--muted-2);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.lab-menu {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.lab-menu a {
  display: flex;
  align-items: center;
  min-height: 38px;
  padding: 0 10px;
  border-radius: 6px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 550;
}

.lab-menu a:hover {
  background: var(--surface);
  color: var(--text);
  text-decoration: none;
}

.lab-menu a.active {
  background: var(--accent-dim);
  color: var(--accent);
}

.lab-content { min-width: 0; }
.lab-content .source-toolbar { top: 63px; }

@media (max-width: 760px) {
  .lab-shell { display: block; }
  .lab-sidebar {
    position: sticky;
    top: 63px;
    z-index: 30;
    border-right: 0;
    border-bottom: 1px solid var(--border-soft);
  }
  .lab-sidebar-inner {
    position: static;
    display: flex;
    align-items: center;
    min-width: 0;
    gap: 14px;
    padding: 10px 18px;
  }
  .lab-label { margin: 0; }
  .lab-menu { flex: 1; min-width: 0; flex-direction: row; overflow-x: auto; scrollbar-width: none; }
  .lab-menu::-webkit-scrollbar { display: none; }
  .lab-menu a { flex: 0 0 auto; min-height: 34px; padding: 0 12px; }
  .lab-content .source-toolbar { top: 118px; }
}