Want to make text look big ? Think about the reason first, maybe it is a title and <h1-6> should be used. Maybe it is an important word, use <strong>. If it is a subtitle, use body and overline variant. Once the correct semantic is used, you may have a selector ready. Read the full Material Design guideline to design Typography

1. Company CSS (brand, colors, logo, typography)
2. Site CSS (colors, visual design)
3. Site Category CSS (Consistent visual for a site category (news, weather))
4. Page Specific CSS (used only on 1 page)

By putting the most common CSS in company wide css, you get visual consistency for free, and best code reuse. Alternatively with SASS or LESS, one could declare site-wide variables and import those where required.

• 1 Component, 1 CSS

Can be further extended on individual site categories or pages.

One best method to implement subcategorize CSS is to use JSS. JSS stands for Javascript Style sheet. In JSS, CSS is written in a javascript object and then it is parsed by parse in actual css. Write one JSS for one component. Check official documentation of JSS

Should be as short as possible. Use the element selector only when it makes sense (e.g for site wide styles) . Use descendant, and child selector when the associated markup also follows this hierarchy

Put the most important ones first

0. Content
1. Positioning and layout
2. Margin, Border, Padding, Width, Height
3. Font
4. Colors

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