.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-mobile-trigger { display: none; }
.lab-sidebar-panel { min-width: 0; }

.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-language {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3px;
  margin: 24px 8px 0;
  padding: 3px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
}

.lab-language button {
  min-height: 28px;
  padding: 0 6px;
  border: 0;
  border-radius: 4px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font: 600 10px 'SF Mono', Menlo, monospace;
}

.lab-language button.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: 55px;
    z-index: 45;
    border-right: 0;
    border-bottom: 1px solid var(--border-soft);
    background: rgba(10, 14, 20, .96);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
  }
  .lab-sidebar-inner {
    position: relative;
    padding: 7px 12px;
  }
  .lab-mobile-trigger {
    display: grid;
    width: 100%;
    min-height: 42px;
    grid-template-columns: auto 1fr 20px;
    align-items: center;
    gap: 9px;
    padding: 0 11px;
    border: 1px solid var(--border-soft);
    border-radius: 9px;
    background: var(--surface);
    color: var(--text);
    cursor: pointer;
    text-align: left;
    -webkit-tap-highlight-color: transparent;
  }
  .lab-mobile-trigger span {
    color: var(--accent);
    font: 700 9px 'SF Mono', Menlo, monospace;
    letter-spacing: .08em;
    text-transform: uppercase;
  }
  .lab-mobile-trigger strong {
    overflow: hidden;
    font-size: 13px;
    font-weight: 650;
    text-overflow: ellipsis;
    white-space: nowrap;
  }
  .lab-mobile-trigger svg {
    width: 20px;
    height: 20px;
    fill: none;
    stroke: var(--muted);
    stroke-width: 1.7;
    stroke-linecap: round;
    stroke-linejoin: round;
    transition: transform .16s ease;
  }
  .lab-sidebar.open .lab-mobile-trigger {
    border-color: rgba(88, 166, 255, .45);
    background: var(--accent-dim);
  }
  .lab-sidebar.open .lab-mobile-trigger svg { transform: rotate(180deg); }
  .lab-sidebar-panel {
    position: absolute;
    top: calc(100% + 1px);
    right: 0;
    left: 0;
    display: none;
    max-height: calc(100dvh - 184px);
    padding: 12px;
    border-bottom: 1px solid var(--border);
    background: rgba(13, 17, 23, .99);
    box-shadow: 0 18px 36px rgba(0, 0, 0, .45);
    overflow-y: auto;
    overscroll-behavior: contain;
  }
  .lab-sidebar.open .lab-sidebar-panel { display: block; }
  .lab-label { display: none; }
  .lab-menu {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 6px;
  }
  .lab-menu a {
    min-width: 0;
    min-height: 44px;
    padding: 0 12px;
    border: 1px solid var(--border-soft);
    background: var(--surface);
    font-size: 12px;
  }
  .lab-menu a.active { border-color: rgba(88, 166, 255, .35); }
  .lab-language {
    width: 100%;
    margin: 10px 0 0;
  }
  .lab-language button { min-height: 34px; }
  .lab-content .source-toolbar { top: 112px; }
}