[KevinH]

Hi BeckyEbook
Thank you! I already found your FindReplace font family and size one and added it to the new Advanced Topics chapter but will add the others.

Originally Posted by BeckyEbook

My experiments don't always lend themselves to wider use, and then I'm the only person in the world who uses such non-standard settings, because, after all, it's mostly about individual taste.
I work in Sigil practically every day, so my preferences are simply due to the mode of this work, which is why, among other things, I have a validation results box above Code View, because I mostly analyze the results of validation plugins.
It is also important to note that my changes are more about Windows in a Classic Sigil Dark Theme.

/* Setting the monotype font in the Find and Replace fields */
/* Instead of "Consolas" use your favorite font, preferably the one you use in Code View. */
#cbFind, #cbReplace {font-family: "Consolas"; font-size: 12px;}

/* Change the default selection color to a similar green color scheme for the new logo/icon. */ 
*,
*::separator,
*::handle,
*::tab-bar,
*::tab,
*::section {
  selection-background-color: #00404a;
  selection-color: white;
}

/* Sigil version number in About box in different color */
QLabel#lbVersionDisplay {color: #FFA000;}

/* Gray background in About box on Authors tab */
QTextEdit#creditsDisplay {background-color: #323232;}

/* Gray background of the BookBrowser panel */
#bookbrowser {background-color: #323232;}

/* No BookBrowser panel borders  */
#bookbrowser {border: 1px solid #323232;}

/* No Find&Replace panel borders */
QFrame {border: 1px solid #323232;}