The Structurizr software architecture modelling language enables the creation of multiple software architectural diagrams from textually defined C4 models. Structurizr has been implemented from scratch instead of reusing existing modelling technologies, which would have allowed for leveraging existing work on automated validation and model transformation. This untapped potential motivates the need to reimplement Structurizr as a hybrid graphical-textual DSL, with the intent of integrating C4 models in MDE processes. We have developed a hybrid DSL and its supporting editor for a subset of Structurizr, providing a tree-based graphical syntax for the definition of C4 models and a diagram-based graphical syntax for the architectural diagram views. Moreover, the hybrid DSL editor provides a smart textual editor with syntax-aware editing features, for specifying inclusion expressions. Our partial reimplementation of Structurizr comprises C4 elements such as software systems, containers, components, persons, and relationships, and additionally, architectural diagrams for system and container contexts, that can be filtered based on inclusion expressions.