learning-playground

Chapter 1: CSS Fundamentals

• History
  • First proposed in 1994
  • CSS1 in 1996
  • CSS2 in 1998
  • CSS3 in 1999 (not explicitly mentioned in the book..?)

• Stylesheet contents consist of rules

  • Rules: <selector> <declaration-block>
    • declaration-block: one or more declarations
    • Declarations: <property>: <value>
    • Vendor prefixing as of this book (2023) is effectively dead (…technically some out there, but not really)
  • Whitespace is ignored/collapsed by parsers
  • Comments - Only /* */ supported, no “end-of-line” (// comment)
  • Elements
    • Two forms:
      • Replaced - content replaced by something (e.g., <img> replaced with an actual…image)
      • Non-replaced - content as-is (e.g., <p>, <span>)
    • Display Roles - block formatting context, inline formatting context
      • block
        • Fill its parent’s content area / cannot have element at its side
        • E.g., <div>, <p>
      • inline
        • Don’t generate a break
        • E.g., <a>, <strong>, <em>
• Ways to define stylesheets
  • Persistent - <link rel="stylesheet">
    • rel="stylesheet" without a title
    • Always used/included regardless of user changing
  • Preferred - <link rel="stylesheet" title="Some Title">
    • `rel=”stylesheet” with a title
    • Used as the default behavior if the user doesn’t switch it
  • Alternate <link rel="alternate stylesheet" title="Other">
    • `rel=”alternate stylesheet” with a title
    • Used only if user changes it, overriding preferred
    • Can only use one at a time
• Apparently, HTTP headers can return stylesheets (Firefox/Opera really only support it?)
• Inline `style=”color: red;” is discouraged by book/authors

Examples

• Alternative Stylesheets