Firefox 48.x
“Stylish Developer Tool is a free browser add-on for the Firefox web browser that adds Stylish style editing capabilities right into Firefox’s Developer Tools. …”
Source: gHacks Tech News
Details 
Stylish Developer Tool for Firefox
Firefox 48.x
“Stylish Developer Tool is a free browser add-on for the Firefox web browser that adds Stylish style editing capabilities right into Firefox’s Developer Tools. …”
Source: gHacks Tech News
Details Stylish Developer Tool for Firefox