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How to tweak Reader View to get a darker sepia background

  • I have long wanted to change the far too light "sepia" colour in Reader View (Version 2) by bernarpa - the reader that is a porting of Firefox Reader View.

    Details of how I did this on a PC running Windows 10 Pro are below.

    But it should not have worked! Any change to an extension (other than by updating it) should result in the change being detected and the extension being disabled. This does not happen with this extension, possibly because it is now pretty old.

    Note: the extension folder name is possibly random (in my case gfaafookaidboehhnhojbebjpjbnnfg) but you can identify the correct one by the sub folder name which is the version (in this case 2_0) and by the contents therein.

    Replace the HTML color code #FFFAFD with #e7d9c3 or with any color code you like in the following two files.

    (For color examples, see or

    To change reader view page background colour: content.js located in:

    C:\Users{your user name}\AppData\Roaming\Opera Software\Opera Stable\Extensions/gfaafookaidboehhnhojbebjpjbnnfgl/2_0/js

    search for the phrase color === 'sepia’

    html += " } else if (color === 'sepia') {"
    html += " = '#e7d9c3';";

    To change the Sepia button colour: aboutReaderControls.css located in:

    C:\Users{your user name}\AppData\Roaming\Opera Software\Opera Stable\Extensions/gfaafookaidboehhnhojbebjpjbnnfgl/2_0/css

    search for the text “sepia-button”

    .sepia-button {
    color: black;
    background-color: #e7d9c3;

  • Closed as duplicated.