Changes

<context>\definepapersize[sheet][width=10.2cm,height=2.2cm]\setuppapersize[sheet]\setuplayout [topspace=1mm, backspace=1mm, header=0pt, headerdistance=0pt, footer=0pt, footerdistance=5mm, width=10cm, heigth=2cm] \setuppagenumbering[none] % page numbers are always useful\showframe[edge] % Draw line around each page. Prevents overzealous cropping \definefontfamily [mainface] [serif] [DejaVu Serif]\definefontfamily [mainface] [sans] [DejaVu Sans]\definefontfamily [mainface] [mono] [DejaVu Sans Mono] [feature=none]\definefontfamily [mainface] [math] [TeX Gyre Pagella Math] \setupbodyfont[mainface]\starttext\startlines\switchtobodyfont[20pt]\rm DejaVu Serif\ss DejaVu Sans\tt DejaVu Sans Mono\m{c^2 = a^2 + b^2}\stoplines\stoptext </context>|[https://www.fontsquirrel.com/fonts/dejavu-sans DejaVu <context>\setupbodyfont[dejavusans]\ss\tfd DejaVu Sans</context>]|[https://www.fontsquirrel.com/fonts/dejavu-sans-mono <context>\setupbodyfont[dejavusansmono]\tt \tfd DejaVu Sans Mono</context>]