Cascading Style Sheets (CSS)

Monday May 14, GTC West, Class P20

CSS Cascade

Rules effect things below them:
<body> rules effect <p>

When Rules Fight...

  • Closer is stronger
  • #id is stronger than .class is stronger than tag
  • Last rule wins

More CSS Syntax

  • /* comment */
  • ',' means 'and'
  • ' ' means 'descendent'
  • '*' means 'everything'
  • '>' means 'child'
  • '+' means 'sibling'
  • :link, :visited
  • :hover, :focus, :active

Right Column

CSS Cascade: More Syntax

  • Comments:
    • /* This is a CSS Comment */
  • Select Multiples
    • h1, h2, h3 { font-family: arial; }
    • <h1>'s and <h2>'s and <h3>'s are arial
  • Select Descendents
    • div p { color: red}
    • Note the ' ' (space)
      • div [space] p
    • <p>'s that are inside <div>'s are red
    • Question: What's This:
      div h1 h2 h3 { font-weight: bold; }
    • And this?
      div h1, div h2, div h3 { font-weight: bold; }
  • Select Everything
    • * { background-color: white }
    • everything is on white
    • rarely used
  • Select Immediate Child
    • div > ol { color: orange }
      • Only <ol>'s that are directly inside <div>'s
    • div#navigation > ul.topNav { color: white; }
      • Only an <ul> with class "topNav" inside of a <div> with id "navigation"
  • Select Sibling
    • h1 + p { margin-top: 0px; }
      • Only a <p> right after an <h1>
    • h3.sideBar + p { margin-top: 0px; }
      • Only a <p> right after an <h3> with class "sideBar"
  • Psuedo-Selectors
    • :link and :visited (<a> tags)
    • :hover (mouse moves over)
      • a:hover { }
      • a.mainNav:hover { }
    • :focus (element with focus)
    • :active (element that has been activated - e.g. a link while being clicked down)
      • Usually <a>
      • a:active { color: #FF0000; }