You can use this regular expression (any whitespace or any non-whitespace) as many times as possible down to and including 0.
[\s\S]*
This expression will match as few as possible, but as many as necessary for the rest of the expression.
[\s\S]*?
For example, in this regex [\s\S]*?B
will match aB
in aBaaaaB
. But in this regex [\s\S]*B
will match aBaaaaB
in aBaaaaB
.