Other helpers

更多的预设模式

Here are some other helpers shipped with Bulma:

`is-clearfix`	Fixes an element's floating children
`is-pulled-left`	Moves an element to the left
`is-pulled-right`	Moves an element to the right
`is-overlay`	Completely covers the first positioned parent
`is-clipped`	Adds overflow hidden
`is-radiusless`	Removes any radius
`is-shadowless`	Removes any shadow
`is-unselectable`	Prevents the text from being selectable
`is-clickable`	Applies `cursor: pointer !important` to the element.
`is-relative`	Applies `position: relative` to the element.