# [Retina], 129 bytes

    \d+
    $* c /
    ^ 
    
    +`^( *) c( +/)
    $1c  $2¶$&
     /$
    _/
    c ( {4})*/
    c $#1/
    \d+
    $*a
    c   ( {4})*/
    c$#1/
    \d+
    $*bb
    a
     |  
    b
    / c 
    m`c /$
    c/
    c
    \

[Try it online!][TIO-j9ec1bog]

[Retina]: https://github.com/m-ender/retina
[TIO-j9ec1bog]: https://tio.run/##TY07DsIwEET7OcVIrCJ/isURx4lC7A1FCigiOuBaOQAXM45o0s3ojd6st@fyyLUOc4QEGhUjgTiNjsHTHKN6SDJS@u8mHaiCq8Lo@Lp8fNijnJLir8it8sAOqBRk8E2iQNsV7pPtNmszDLWm8w8 "Retina – Try It Online"