Header Side Rotated
A TB section whose trunk drops through the top edge and exits the bottom edge blocks the header on both horizontal edges. The title rotates and runs down the clear left edge instead of crossing the line.
Mermaid source
%%metro title: Header Rotated Onto Side%%metro style: dark%%metro line: a | A | #e63946
%%metro grid: src_sec | 0,0%%metro grid: tgt_sec | 0,1%%metro grid: snk_sec | 0,2
graph LR subgraph src_sec [Up] %%metro direction: TB %%metro exit: bottom | a s1[One] end
subgraph tgt_sec [Align] %%metro direction: TB %%metro entry: top | a %%metro exit: bottom | a t1[Two] t2[Three] t1 -->|a| t2 end
subgraph snk_sec [Down] %%metro direction: TB %%metro entry: top | a k1[Four] end
s1 -->|a| t1 t2 -->|a| k1CLI command
nf-metro render examples/topologies/header_side_rotated.mmd -o header_side_rotated.svg