Apply Material Design to Chrome extension UI

We are seeking a designer with significant experience in UI design and with simple, minimalist, highly-usable interfaces in particular. Expert-level proficiency with HTML and CSS is required. Specific experience with Material Design would be ideal. Experience with Chrome extensions helpful, but not required, as the UI is implemented with HTML and CSS. We have Chrome extension in the beta stage. It is relatively simple, inserting various elements in two different areas of pages matching a regex. The Options panel currently includes five tabs for the configuration of various settings. Most tabs have only three or four elements, currently consisting of checkboxes, radio buttons, and text entry areas. One tab contains about a dozen elements. Prior to launch (and if necessary, before the designer begins work), we will establish "Basic" and "Advanced" modes, with most settings hidden unless "Advanced" mode is enabled. The elements inserted in the pages include a table, conditional and dynamic links, and a set of filters including a calendar widget (for defining a date) which we would like to replace. We would like to overhaul the interface, mainly the Options panel, but also the new elements inserted in pages, to provide a simpler, cleaner design. For the Options UI, we would like to implement Google's Material Design guidelines. For the elements inserted in the pages, we want to match the look of the native page elements, with Material Design as a fallback where appropriate. We have another front end developer who has created the rest of the extension and will continue to work on functional improvements and bug fixes. Deliverables would consist of wireframes or mockups, followed by HTML and CSS to be applied by the other developer. Ideas are welcome, but anything that requires rewriting code (except for bug fixes) would need to wait for a later version. We will provide an extension icon, and possibly some additional hex values, to guide the palette choices. A text logo will follow shortly thereafter.