gistfile1.coffee

  # setup variables 
  $window = $ window
  $section = $ '.tour-section'
  $intro = $ '.tour-intro'

  adjustWindow = ->

    winH = $window.height()
    win2 = winH * 2

    winH = 550 if winH <= 550

    $intro.height winH
    $section.height winH * 2
  
    $body = $ "body"

    $body.attr "data-#{winH}", $body.attr("data-intro")

    for i in [1..8]
      $body.attr "data-#{win2 * i}", $body.attr "data-section-#{i}"
      $body.removeAttr "data-section-#{i}"
      
    $body.attr "data-#{winH}", $body.attr 'data-intro'
    $body.removeAttr 'data-intro'
      
  adjustWindow()

  $window.on "resize", -> 
    adjustWindow()

gistfile2.haml

%body{"data-intro" => "background: rgb(81, 86, 109)",
  "data-section-1" => "background: rgb(69, 82, 121)",
  "data-section-2" => "background: rgb(94, 107, 151)",
  "data-section-3" => "background: rgb(68, 74, 100)",
  "data-section-4" => "background: rgb(94, 108, 154)",
  "data-section-5" => "background: rgb(67, 72, 95)",
  "data-section-6" => "background: rgb(65, 73, 104)",
  "data-section-7" => "background: rgb(41, 50, 71)",
  "data-section-8" => "background: rgb(94, 109, 157)"}