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HTML

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CSS

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JavaScript

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HTML 

              
                <!--example of left sidebar with content on right side-->
.cols
  .col_one_third.media_xs_order_two
    %div [sidebar]
    
  .col_two_thirds.media_xs_order_one
    %div [main]

<!--three equal columns-->
.cols
  .col_one_third.media_xs_order_two
    %div 1
    
  .col_one_third.media_xs_order_three
    %div 2
  
  .col_one_third.media_xs_order_one
    %div 3
!

CSS 

              
                @import compass

// The CSS is written as Sass to abstract the vendor prefixes into mixins.

$app-media-xs: 767px // For narrow/mobile media query

// browser prefixes for flexbox container
@mixin flexbox
  display: -webkit-box
  display: -moz-box
  display: -ms-flexbox
  display: -webkit-flex
  display: flex

// browser prefixes for direction
@mixin flex-direction
  -moz-box-orient: vertical
  -webkit-box-orient: vertical
  -ms-box-orient: vertical
  -webkit-flex-direction: column
  flex-direction: column

// browser prefixes for ordering
@mixin flex-order($val)
  -webkit-box-ordinal-group: $val+1
  -moz-box-ordinal-group: $val+1
  -ms-flex-order: $val
  -webkit-order: $val
  order: $val

// basic columns
.cols
  clear: both
    
  // clearfix
  &:after
    visibility: hidden
    display: block
    font-size: 0
    content: " "
    clear: both
    height: 0
    
  > div
    @include box-sizing(border-box)
    min-height: 1px
    
  // switch cols to flexbox with a media query
  @media screen and (max-width: $app-media-xs)
    @include flexbox
    @include flex-direction
    > div
      float: none !important
      width: 100%
      padding-left: 0 !important
      padding-right: 0 !important

// three equal columns
.col_one_third
  float: left
  width: 33.33%
  padding: 0 1em

// combine with .col_one_third
.col_two_thirds
  float: left
  width: 66.67%
  padding: 0 1em

// fixes the first and last column
.col_one_third
  &:first-of-type
    clear: left
    padding: 0 2.077em 0 0

  &:last-of-type
    clear: right
    padding: 0 0 0 2.077em

// fixes the first and last column for columns that will always be in the first or last position
.col_two_thirds
  &:first-of-type
    clear: left
    padding-left: 0

  &:last-of-type
    clear: right
    padding-right: 0

// add these classes to change the order of content
@media screen and (max-width: $app-media-xs)
  .media_xs_order_one
    @include flex-order(0)

  .media_xs_order_two
    @include flex-order(1)

  .media_xs_order_three
    @include flex-order(2)
      
// the following CSS is just for displaying the demo
body
  padding: 2em 2em 0 // demo
  background-color: #e6e5df // demo
  font-family: Georgia, serif // demo
  font-size: 1.5em // demo
  text-align: center // demo
  
.cols > div div
  margin-bottom: 2em // demo
  padding: 1.5em // demo
  background-color: #f8ca00 // demo
!

JS
!
999px

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