## Guiding principles
-Beyond what Bootstrap does, here's _why_ we do it—our philosophy for building on the web. At a high level, here's what guides our approach:
+Beyond what Bootstrap does, here's *why* we do it—our philosophy for building on the web. At a high level, here's what guides our approach:
- Components should be responsive and mobile-first
- Components should be built with a base class and extended via modifier classes
Some components in Bootstrap are built with overlapping elements to prevent double borders without modifying the `border` property. For example, button groups, input groups, and pagination. These components share a standard `z-index` scale of `0` through `3`, matching our expectations of highest user priority.
- `0` is for default states (initial, not actually set)
-- `1` is for `:hover`, lowest because while it indicates user intent, nearly _anything_ can be hovered.
+- `1` is for `:hover`, lowest because while it indicates user intent, nearly *anything* can be hovered.
- `2` is for `:active`/`.active`, second highest because they indicate state.
- `3` is for `:focus`, highest because focused elements are in view and at the user’s attention.
</html>
```
-2. **Include Bootstrap’s CSS and JS.** Place the `<link>` tag in the `<head>` for our CSS, and the `<script>` tag for our JavaScript bundle (including Popper for positioning dropdowns, popovers, and tooltips) before the closing `</body>`. Learn more about our [CDN links](#cdn-links).
+2. **Include Bootstrap’s CSS and JS.** Place the `<link>` tag in the `<head>` for our CSS, and the `<script>` tag for our JavaScript bundle (including Popper for positioning dropdowns, popovers, and tooltips) before the closing `</body>`. Learn more about our [CDN links]([[docsref:/getting-started/install#cdn]]).
```html
<!doctype html>
projects / thirdparty / bootstrap.git / commitdiff
