gnus: FAQ 4-16

 
 Question 4.16
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 How can I ensure more contrast when viewing HTML mail?
 
 Answer
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 Gnus’ built-in simple HTML renderer (you use it if the value of
 ‘mm-text-html-renderer’ is ‘shr’) uses the colors which are declared in
 the HTML mail.  However, it adjusts them in order to prevent situations
 like dark gray text on black background.  In case the results still have
 a too low contrast for you, increase the values of the variables
 ‘shr-color-visible-distance-min’ and ‘shr-color-visible-luminance-min’.