I'm leaning toward an SMACSS approach so we can have a core set of classes that share a base set of styles and different themes can add their "extensions" to overide the original UI.

For instance, a button might be in a .php/.html file as:
```
<button class"btn">My button</button>
```
But then someone comes along and says, "hey, I want this button to have wayyy more spacing than what every other developer has been doing. They could then create `style_my-awesome-theme.scss` which would simply be:
```
@import "core";
.btn {
   padding: 25px;
}
```
So others can see exactly what's different between the original (core) and the extended theme. If you want to bring along some of the in-progress bootstrap styles, you'll have to add the following imports below your custom styles:
```
@import "oe-bootstrap";
@import "oe-common/all-common-import";
```

**Running `npm run build` and/or `npm run dev` will generate a new style_my-awesome-theme.css file that _should_ appear in the theme list in the app settings**