Form control
Give textual form controls like <input> and <textarea> styling and focus states with .form-control.
Example
Sizing
Set heights using classes like .form-control-lg and .form-control-sm.
Password / text buttons
Fewer CSS is needed for these; pair inputs with .input-group for prepended buttons (see Input group).
File input
File inputs are fully styled out of the box, with a hover state for the "select file" button.
Color
Plain text
Use .form-control-plaintext to strip the input chrome while keeping the layout: