Text alignment and float utility classes

Utility classes for floats and text alignment now have responsive ranges. Bootstrap 4 has dropped nonresponsive text alignment and float classes.

Responsive text alignment classes are of the text-[xs/sm/md/lg/xl]-[left/right/center] format. For example, the text-lg-left class left aligns text on viewports sized lg or wider.

Classes of the format pull-[xs/sm/md/lg/xl]-[left/right/none] float an element to the left or right or disable floating based on the current viewport size. For example, the pull-xs-left class floats the element left on all viewport sizes.