* fix: restructure certifications guide articles * fix: added 3 dashes line before prob expl * fix: added 3 dashes line before hints * fix: added 3 dashes line before solutions
Added hint to Attach a Fallback Value to a CSS Variable (https://guide.freecodecamp.org/certifications/responsive-web-design/basic-css/attach-a-fallback-value-to-a-css-variable/)