In the interest of customization and cross browser consistency, Bootstrap include a handful of customized form elements. They're solid replacements for default form controls as they're built on top of semantic and accessible markup.
Each checkbox and radio is wrapped in a `<label>` for three reasons:
- It provides a larger hit areas for checking the control.
- It provides a helpful and semantic wrapper to help us replace the default `<input>`s.
- It triggers the state of the `<input>` automatically, meaning no JavaScript is required.
We hide the default `<input>` with `opacity` and use the `.c-indicator` to build a new custom form control. We can't build a custom one from just the `<input>` because CSS's `content` doesn't work on that element.
With the sibling selector (`~`), we use the `:checked` state to trigger a makeshift checked state on the custom control.
In the checked states, we use **base64 embedded SVG icons** from [Open Iconic](http://useiconic.com/open). This provides us the best control for styling and positioning across browsers and devices.
