flowchart LR
    subgraph external
      subgraph internal
          inside
      end
    end
    outside --> inside
    

flowchart LR
    subgraph parent
      subgraph childB
        grandchild
      end
    end
    foo --> childA        

      gantt
        title Style today marker (vertical line should be 5px wide and half-transparent blue)
        dateFormat YYYY-MM-DD
        axisFormat %d
        todayMarker stroke-width:5px,stroke:#00f,opacity:0.5
        section Section1
        Today: 1, -1h