+.Ss ASCII Output
+Output produced by
+.Fl T Ns Cm ascii ,
+which is the default, is rendered in standard 7-bit ASCII documented in
+.Xr ascii 7 .
+.Pp
+Font styles are applied by using back-spaced encoding such that an
+underlined character
+.Sq c
+is rendered as
+.Sq _ Ns \e[bs] Ns c ,
+where
+.Sq \e[bs]
+is the back-space character number 8.
+Emboldened characters are rendered as
+.Sq c Ns \e[bs] Ns c .
+.Pp
+The special characters documented in
+.Xr mandoc_char 7
+are rendered best-effort in an ASCII equivalent.
+If no equivalent is found,
+.Sq \&?
+is used instead.
+.Pp
+Output width is limited to 78 visible columns unless literal input lines
+exceed this limit.
+.Pp
+The following
+.Fl O
+arguments are accepted:
+.Bl -tag -width Ds
+.It Cm indent Ns = Ns Ar indent
+The left margin for normal text is set to
+.Ar indent
+blank characters instead of the default of five for
+.Xr mdoc 7
+and seven for
+.Xr man 7 .
+Increasing this is not recommended; it may result in degraded formatting,
+for example overfull lines or ugly line breaks.
+.It Cm width Ns = Ns Ar width
+The output width is set to
+.Ar width ,
+which will normalise to \(>=60.
+.El
+.Ss HTML Output
+Output produced by
+.Fl T Ns Cm html
+conforms to HTML-4.01 strict.
+.Pp
+The
+.Pa example.style.css
+file documents style-sheet classes available for customising output.
+If a style-sheet is not specified with
+.Fl O Ns Ar style ,
+.Fl T Ns Cm html
+defaults to simple output readable in any graphical or text-based web
+browser.
+.Pp
+Special characters are rendered in decimal-encoded UTF\-8.
+.Pp
+The following
+.Fl O
+arguments are accepted: