You can register and use [custom theme CSS for Marpit](https://marpit.marp.app/theme-css) / [Marp Core](https://github.com/marp-team/marp-core/tree/main/themes#readme) by setting `ThemePath`, that includes relative paths to local files in the current vault.
The registered theme can use by specifying theme name in [`theme` global directive](https://marpit.marp.app/directives?id=theme).
Theme.css:
```css
/* @theme your-theme */
@import'default';
section{
background:#fc9;
}
```
Slides.md:
```markdown
---
theme:your-theme
---
# Use your own theme
---
# Second Slide
```
Markdown preview will reload updated theme CSS automatically when you edited the registered local CSS file.
