How can I change the color of the lines between ticks?

[ariehen]

I’d have a good read through this:

Obsidian CSS Inspector Workflow

Obsidian CSS Inspector Workflow This was originally called “Obsidian CSS Quick Guide” but it ended up being more focused on the inspector. As a retrospective change to help people use this as a resource, it has been renamed. – FireIsGood Hi friends! CSS in Obsidian can be confusing to get into, so this is a guide to get you started with information on the tools, methods, and some background knowledge! Let’s get started by looking at how you can look behind the curtain of Obsidian’s visuals. …

and start poking around with the inspector, have a look at Obsidian’s own app.css, the default theme’s custom properties / variables, and other theme.css files. Have fun!