Very good Sketch skills. I've recently been using the Sketch app for wireframing as then the wireframes can directly be used by our Graphic Designers thus cutting down on unnecessary steps in our process.
Using linked SmartObjects in combination with Layercomps in Photoshop CC
Web designers use CSS sprites to reduce the number of requests made by a web page. Essentially a composite image, made up of many smaller images, is used as a common background for a slew of elements, and then the relevant image is ‘revealed’ using CSS.
KSS · Knyle Style Sheets - is intended to help automate the creation of a living styleguide. A styleguide serves as a place to publish KSS documentation and visualize different states of UI elements defined in your CSS.