// proof
#let blue_ = text.with(fill: blue)

#let Assume = text("Assume", fill: blue)
#let imp = blue_[$==>$]
#let iff = text($<==>$, fill: blue)

#let wts = text("Want To Show", fill: blue)

#let If = text("If", fill: blue)
#let Then = text("Then", fill: blue)

#let exist = text(sym.exists, fill: blue)
#let st = text("s.t.", fill: blue)
#let ie = blue_("i.e.")

#let ok = text(fill: green.darken(30%), $checkmark$, weight: "bold")
