Enclose

Frame, highlight, cancel, or strike through a math operand.

Property	Default	Meaning
children	Empty	TeX or an element.
notation	"box"	"box", "colorbox", "cancel", "bcancel", "xcancel", or "sout".
background	Absent	Background paint for box/colorbox.
border-color	Inherited color	Border or cancellation paint.
padding	em(0.3)	Space inside a box, in addition to its border.
thickness	TeX rule, or em(0.046) for cancellation	Border/line thickness.

Boxes enlarge the logical dimensions and preserve the body's baseline with padding. Cancellation and strikeout retain the original dimensions; their lines draw over the body and can extend beyond it. A single-character cancel extends vertically; a compound cancel extends horizontally. The result is an ordinary atom.

TeX forms include \boxed, \fbox, \colorbox, \fcolorbox, \cancel, \bcancel, \xcancel, and text-mode \sout. The text-box forms accept math between $…$. \phase, \angl, and \angln remain unsupported.