Default labels - change style and placement

Hello, I am working on a custom UI for bpmn modeler and this is an example how my start action looks like (all actions will have same design). What I am trying to achieve is move “start” label what is by default placed under the action into the box and make it blue and larger.

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I have placed it almost properly, but I dont know how to make it larger with blue color
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I have created a custom renderer where I add this condition for placement

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Thanks for help