Buttons are the soul of an interactive Web Application. Buttons
allow users to take actions, and make choices, with a single tap.
Contained buttons are high-emphasis, distinguished by their use of
elevation and fill. They contain actions that are primary to your
app.
In need of a button, but not the hefty background colors they
bring? Replace '.btn-variant' with '.simple-variant'.
Want to attach a link action, at a button tap? Use Link Button
Icon Buttons can be created, by using a SVGor i tags as a child to
parent button. Use the 'btn' class followed by 'simple btn-icon'.
Icons are also appropriate for toggle buttons that allow a single
choice to be selected or deselected, such as adding or removing a
star to an item.
