Frontend Mentor - 3-column preview card component solution

This is a solution to the 3-column preview card component challenge on Frontend Mentor.

What I learned

1. 单位
   • rem for font size
   • pixels for borders
   • em for paddings, margins, and border radius
   • percentage for container width when necessary, 有时也用 pixel
2. "learn more"如果在本页展开应使用 button 而非 anchor

Got ACCESSIBILITY ISSUES After First Submission

• Page must have one main landmark 应使用 header, nav, main, and footer 元素，并添加 role="banner", role="navigation", role="main", and role="contentinfo"以方便依赖读屏器的用户

Useful resources

• ARIA Landmarks Example