Custom visualizations: css, common code, hovers, & modifying existing visualizations

[ljhaywar]

I’m just diving in to the world of custom visualizations. A few questions:

1. Is it possible to link to css files from a custom visualization?
2. Is it possible to share common code between multiple visualizations? For example, perhaps you have common functionality between 3 different types of bar charts that creates a y-axis. You don’t want to duplicate it in all 3 files. Can you reference a common function that creates a y-axis from various visualization files?
3. Can we leverage Looker’s hovers in our custom visualizations?
4. Rather than starting from scratch, I’d like to edit the existing column chart visualization that Looker provides. Where can I find the code Looker uses for its default visualizations?