Mixins

Snippets of reusable CSS to develop faster and keep code readable

Utility mixins

Clearfix

For clearing floats like a boss h5bp.com/q

Webkit-style focus

Center-align a block level element

IE7 inline-block

IE7 likes to collapse whitespace on either side of the inline-block elements. Ems because we're attempting to match the width of a space character. Left version is for form buttons, which typically come after other elements, and right version is for icons, which come before. Applying both is ok, but it will mean that space between those elements will be .6em (~2 space characters) in IE7, instead of the 1 space in other browsers.

Sizing shortcuts

Placeholder text

Text overflow

Requires inline-block or block for proper styling

.clearfix {
  *zoom: 1;
  &:before,
  &:after {
    display: table;
    content: "";
  }
  &:after {
    clear: both;
  }
}

.tab-focus() {
  // Default
  outline: thin dotted #333;
  // Webkit
  outline: 5px auto -webkit-focus-ring-color;
  outline-offset: -2px;
}

.center-block() {
  display: block;
  margin-left: auto;
  margin-right: auto;
}

.ie7-inline-block() {
  *display: inline; /* IE7 inline-block hack */
  *zoom: 1;
}

.ie7-restore-left-whitespace() {
  *margin-left: .3em;

  &:first-child {
    *margin-left: 0;
  }
}

.ie7-restore-right-whitespace() {
  *margin-right: .3em;

  &:last-child {
    *margin-left: 0;
  }
}

.size(@height: 5px, @width: 5px) {
  width: @width;
  height: @height;
}
.square(@size: 5px) {
  .size(@size, @size);
}

.placeholder(@color: @placeholderText) {
  :-moz-placeholder {
    color: @color;
  }
  ::-webkit-input-placeholder {
    color: @color;
  }
}

.text-overflow() {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

Fonts

#font {
  #family {
    .serif() {
      font-family: Georgia, "Times New Roman", Times, serif;
    }
    .sans-serif() {
      font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    }
    .monospace() {
      font-family: Menlo, Monaco, "Courier New", monospace;
    }
  }
  .shorthand(@size: @baseFontSize, @weight: normal, @lineHeight: @baseLineHeight) {
    font-size: @size;
    font-weight: @weight;
    line-height: @lineHeight;
  }
  .serif(@size: @baseFontSize, @weight: normal, @lineHeight: @baseLineHeight) {
    #font > #family > .serif;
    #font > .shorthand(@size, @weight, @lineHeight);
  }
  .sans-serif(@size: @baseFontSize, @weight: normal, @lineHeight: @baseLineHeight) {
    #font > #family > .sans-serif;
    #font > .shorthand(@size, @weight, @lineHeight);
  }
  .monospace(@size: @baseFontSize, @weight: normal, @lineHeight: @baseLineHeight) {
    #font > #family > .monospace;
    #font > .shorthand(@size, @weight, @lineHeight);
  }
}

Grid System

Site container

Le grid system

Fluid grid system

Input grid system

Make a Grid

Use .makeRow and .makeColumn to assign semantic layouts grid system behavior

Form field states (used in forms.less)

Mixin for form field states

.container-fixed() {
  width: @gridRowWidth;
  margin-left: auto;
  margin-right: auto;
  .clearfix();
}

#gridSystem {
  // Setup the mixins to be used
  .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, @columns) {
    width: (@gridColumnWidth * @columns) + (@gridGutterWidth * (@columns - 1));
  } 
  .offset(@gridColumnWidth, @gridGutterWidth, @columns) {
    margin-left: (@gridColumnWidth * @columns) + (@gridGutterWidth * (@columns - 1)) + (@gridGutterWidth * 2);
  }
  .gridColumn(@gridGutterWidth) {
    float: left;
    margin-left: @gridGutterWidth;
  }
  // Take these values and mixins, and make 'em do their thang
  .generate(@gridColumns, @gridColumnWidth, @gridGutterWidth) {
    // Row surrounds the columns
    .row {
      margin-left: @gridGutterWidth * -1;
      .clearfix();
    }
    // Find all .span# classes within .row and give them the necessary properties for grid columns (supported by all browsers back to IE7, thanks @dhg)
    [class*="span"] {
      #gridSystem > .gridColumn(@gridGutterWidth);
    }
    // Default columns
    .span1     { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 1); }
    .span2     { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 2); }
    .span3     { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 3); }
    .span4     { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 4); }
    .span5     { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 5); }
    .span6     { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 6); }
    .span7     { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 7); }
    .span8     { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 8); }
    .span9     { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 9); }
    .span10    { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 10); }
    .span11    { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 11); }
    .span12,
    .container { #gridSystem > .columns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 12); }
    // Offset column options
    .offset1   { #gridSystem > .offset(@gridColumnWidth, @gridGutterWidth, 1); }
    .offset2   { #gridSystem > .offset(@gridColumnWidth, @gridGutterWidth, 2); }
    .offset3   { #gridSystem > .offset(@gridColumnWidth, @gridGutterWidth, 3); }
    .offset4   { #gridSystem > .offset(@gridColumnWidth, @gridGutterWidth, 4); }
    .offset5   { #gridSystem > .offset(@gridColumnWidth, @gridGutterWidth, 5); }
    .offset6   { #gridSystem > .offset(@gridColumnWidth, @gridGutterWidth, 6); }
    .offset7   { #gridSystem > .offset(@gridColumnWidth, @gridGutterWidth, 7); }
    .offset8   { #gridSystem > .offset(@gridColumnWidth, @gridGutterWidth, 8); }
    .offset9   { #gridSystem > .offset(@gridColumnWidth, @gridGutterWidth, 9); }
    .offset10  { #gridSystem > .offset(@gridColumnWidth, @gridGutterWidth, 10); }
    .offset11  { #gridSystem > .offset(@gridColumnWidth, @gridGutterWidth, 11); }
  }
}

#fluidGridSystem {
  // Setup the mixins to be used
  .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, @columns) {
    width: 1% * (@fluidGridColumnWidth * @columns) + (@fluidGridGutterWidth * (@columns - 1));
  }
  .gridColumn(@fluidGridGutterWidth) {
    float: left;
    margin-left: @fluidGridGutterWidth;
  }
  // Take these values and mixins, and make 'em do their thang
  .generate(@gridColumns, @fluidGridColumnWidth, @fluidGridGutterWidth) {
    // Row surrounds the columns
    .row-fluid {
      width: 100%;
      .clearfix();

      // Find all .span# classes within .row and give them the necessary properties for grid columns (supported by all browsers back to IE7, thanks @dhg)
      > [class*="span"] {
        #fluidGridSystem > .gridColumn(@fluidGridGutterWidth);
      }
      > [class*="span"]:first-child {
        margin-left: 0;
      }
      // Default columns
      > .span1     { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 1); }
      > .span2     { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 2); }
      > .span3     { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 3); }
      > .span4     { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 4); }
      > .span5     { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 5); }
      > .span6     { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 6); }
      > .span7     { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 7); }
      > .span8     { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 8); }
      > .span9     { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 9); }
      > .span10    { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 10); }
      > .span11    { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 11); }
      > .span12    { #fluidGridSystem > .columns(@fluidGridGutterWidth, @fluidGridColumnWidth, 12); }
    }
  }
}

#inputGridSystem {
  .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, @columns) {
    width: ((@gridColumnWidth) * @columns) + (@gridGutterWidth * (@columns - 1)) - 10;
  }
  .generate(@gridColumns, @gridColumnWidth, @gridGutterWidth) {
    input,
    textarea,
    .uneditable-input {
      &.span1     { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 1); }
      &.span2     { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 2); }
      &.span3     { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 3); }
      &.span4     { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 4); }
      &.span5     { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 5); }
      &.span6     { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 6); }
      &.span7     { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 7); }
      &.span8     { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 8); }
      &.span9     { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 9); }
      &.span10    { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 10); }
      &.span11    { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 11); }
      &.span12    { #inputGridSystem > .inputColumns(@gridGutterWidth, @gridColumnWidth, @gridRowWidth, 12); }
    }
  }
}

.makeRow() {
  margin-left: @gridGutterWidth * -1;
  .clearfix();
}
.makeColumn(@columns: 1) {
  float: left;
  margin-left: @gridGutterWidth;
  width: (@gridColumnWidth * @columns) + (@gridGutterWidth * (@columns - 1));
}




.formFieldState(@textColor: #555, @borderColor: #ccc, @backgroundColor: #f5f5f5) {
  // Set the text color
  > label,
  .help-block,
  .help-inline {
    color: @textColor;
  }
  // Style inputs accordingly
  input,
  select,
  textarea {
    color: @textColor;
    border-color: @borderColor;
    &:focus {
      border-color: darken(@borderColor, 10%);
      .box-shadow(0 0 6px lighten(@borderColor, 20%));
    }
  }
  // Give a small background color for input-prepend/-append
  .input-prepend .add-on,
  .input-append .add-on {
    color: @textColor;
    background-color: @backgroundColor;
    border-color: @textColor;
  }
}

CSS3 properties

Border Radius

Drop shadows

Transitions

Transformations

Background clipping Heads up: FF 3.6 and under need "padding" instead of "padding-box"

Background sizing

Box sizing

User select For selecting text on the page

Resize anything

CSS3 Content Columns

Opacity

.border-radius(@radius: 5px) {
  -webkit-border-radius: @radius;
     -moz-border-radius: @radius;
          border-radius: @radius;
}

.box-shadow(@shadow: 0 1px 3px rgba(0,0,0,.25)) {
  -webkit-box-shadow: @shadow;
     -moz-box-shadow: @shadow;
          box-shadow: @shadow;
}

.transition(@transition) {
  -webkit-transition: @transition;
     -moz-transition: @transition;
      -ms-transition: @transition;
       -o-transition: @transition;
          transition: @transition;
}

.rotate(@degrees) {
  -webkit-transform: rotate(@degrees);
     -moz-transform: rotate(@degrees);
      -ms-transform: rotate(@degrees);
       -o-transform: rotate(@degrees);
          transform: rotate(@degrees);
}
.scale(@ratio) {
  -webkit-transform: scale(@ratio);
     -moz-transform: scale(@ratio);
      -ms-transform: scale(@ratio);
       -o-transform: scale(@ratio);
          transform: scale(@ratio);
}
.translate(@x: 0, @y: 0) {
  -webkit-transform: translate(@x, @y);
     -moz-transform: translate(@x, @y);
      -ms-transform: translate(@x, @y);
       -o-transform: translate(@x, @y);
          transform: translate(@x, @y);
}
.skew(@x: 0, @y: 0) {
  -webkit-transform: skew(@x, @y);
     -moz-transform: skew(@x, @y);
      -ms-transform: skew(@x, @y);
       -o-transform: skew(@x, @y);
          transform: skew(@x, @y);
}
.translate3d(@x: 0, @y: 0, @z: 0) {
  -webkit-transform: translate(@x, @y, @z);
     -moz-transform: translate(@x, @y, @z);
      -ms-transform: translate(@x, @y, @z);
       -o-transform: translate(@x, @y, @z);
          transform: translate(@x, @y, @z);
}

.background-clip(@clip) {
  -webkit-background-clip: @clip;
     -moz-background-clip: @clip;
          background-clip: @clip;
}

.background-size(@size){
  -webkit-background-size: @size;
     -moz-background-size: @size;
       -o-background-size: @size;
          background-size: @size;
}


.box-sizing(@boxmodel) {
  -webkit-box-sizing: @boxmodel;
     -moz-box-sizing: @boxmodel;
          box-sizing: @boxmodel;
}

.user-select(@select) {
  -webkit-user-select: @select;
     -moz-user-select: @select;
       -o-user-select: @select;
          user-select: @select;
}

.resizable(@direction: both) {
  resize: @direction; // Options: horizontal, vertical, both
  overflow: auto; // Safari fix
}

.content-columns(@columnCount, @columnGap: @gridColumnGutter) {
  -webkit-column-count: @columnCount;
     -moz-column-count: @columnCount;
          column-count: @columnCount;
  -webkit-column-gap: @columnGap;
     -moz-column-gap: @columnGap;
          column-gap: @columnGap;
}

.opacity(@opacity: 100) {
  opacity: @opacity / 100;
   filter: e(%("alpha(opacity=%d)", @opacity));
}

Backgrounds

Add an alphatransparency value to any background or border color (via Elyse Holladay)

Gradient Bar Colors for buttons and alerts

Gradients

Reset filters for IE

Mixin for generating button backgrounds

#translucent {
  .background(@color: @white, @alpha: 1) {
    background-color: hsla(hue(@color), saturation(@color), lightness(@color), @alpha);
  }
  .border(@color: @white, @alpha: 1) {
    border-color: hsla(hue(@color), saturation(@color), lightness(@color), @alpha);
    .background-clip(padding-box);
  }
}

.gradientBar(@primaryColor, @secondaryColor) {
  #gradient > .vertical(@primaryColor, @secondaryColor);
  border-color: @secondaryColor @secondaryColor darken(@secondaryColor, 15%);
  border-color: rgba(0,0,0,.1) rgba(0,0,0,.1) fadein(rgba(0,0,0,.1), 15%);
}

#gradient {
  .horizontal(@startColor: #555, @endColor: #333) {
    background-color: @endColor;
    background-image: -moz-linear-gradient(left, @startColor, @endColor); // FF 3.6+
    background-image: -ms-linear-gradient(left, @startColor, @endColor); // IE10
    background-image: -webkit-gradient(linear, 0 0, 100% 0, from(@startColor), to(@endColor)); // Safari 4+, Chrome 2+
    background-image: -webkit-linear-gradient(left, @startColor, @endColor); // Safari 5.1+, Chrome 10+
    background-image: -o-linear-gradient(left, @startColor, @endColor); // Opera 11.10
    background-image: linear-gradient(left, @startColor, @endColor); // Le standard
    background-repeat: repeat-x;
    filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=1)",@startColor,@endColor)); // IE9 and down
  }
  .vertical(@startColor: #555, @endColor: #333) {
    background-color: mix(@startColor, @endColor, 60%);
    background-image: -moz-linear-gradient(top, @startColor, @endColor); // FF 3.6+
    background-image: -ms-linear-gradient(top, @startColor, @endColor); // IE10
    background-image: -webkit-gradient(linear, 0 0, 0 100%, from(@startColor), to(@endColor)); // Safari 4+, Chrome 2+
    background-image: -webkit-linear-gradient(top, @startColor, @endColor); // Safari 5.1+, Chrome 10+
    background-image: -o-linear-gradient(top, @startColor, @endColor); // Opera 11.10
    background-image: linear-gradient(top, @startColor, @endColor); // The standard
    background-repeat: repeat-x;
    filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=0)",@startColor,@endColor)); // IE9 and down
  }
  .directional(@startColor: #555, @endColor: #333, @deg: 45deg) {
    background-color: @endColor;
    background-repeat: repeat-x;
    background-image: -moz-linear-gradient(@deg, @startColor, @endColor); // FF 3.6+
    background-image: -ms-linear-gradient(@deg, @startColor, @endColor); // IE10
    background-image: -webkit-linear-gradient(@deg, @startColor, @endColor); // Safari 5.1+, Chrome 10+
    background-image: -o-linear-gradient(@deg, @startColor, @endColor); // Opera 11.10
    background-image: linear-gradient(@deg, @startColor, @endColor); // The standard
  }
  .vertical-three-colors(@startColor: #00b3ee, @midColor: #7a43b6, @colorStop: 50%, @endColor: #c3325f) {
    background-color: mix(@midColor, @endColor, 80%);
    background-image: -webkit-gradient(linear, 0 0, 0 100%, from(@startColor), color-stop(@colorStop, @midColor), to(@endColor));
    background-image: -webkit-linear-gradient(@startColor, @midColor @colorStop, @endColor);
    background-image: -moz-linear-gradient(top, @startColor, @midColor @colorStop, @endColor);
    background-image: -ms-linear-gradient(@startColor, @midColor @colorStop, @endColor);
    background-image: -o-linear-gradient(@startColor, @midColor @colorStop, @endColor);
    background-image: linear-gradient(@startColor, @midColor @colorStop, @endColor);
    background-repeat: no-repeat;
    filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=0)",@startColor,@endColor)); // IE9 and down, gets no color-stop at all for proper fallback
  }
  .radial(@innerColor: #555, @outerColor: #333)  {
    background-color: @outerColor;
    background-image: -webkit-gradient(radial, center center, 0, center center, 460, from(@innerColor), to(@outerColor));
    background-image: -webkit-radial-gradient(circle, @innerColor, @outerColor);
    background-image: -moz-radial-gradient(circle, @innerColor, @outerColor);
    background-image: -ms-radial-gradient(circle, @innerColor, @outerColor);
    background-repeat: no-repeat;
    // Opera cannot do radial gradients yet
  }
  .striped(@color, @angle: -45deg) {
    background-color: @color;
    background-image: -webkit-gradient(linear, 0 100%, 100% 0, color-stop(.25, rgba(255,255,255,.15)), color-stop(.25, transparent), color-stop(.5, transparent), color-stop(.5, rgba(255,255,255,.15)), color-stop(.75, rgba(255,255,255,.15)), color-stop(.75, transparent), to(transparent));
    background-image: -webkit-linear-gradient(@angle, rgba(255,255,255,.15) 25%, transparent 25%, transparent 50%, rgba(255,255,255,.15) 50%, rgba(255,255,255,.15) 75%, transparent 75%, transparent);
    background-image: -moz-linear-gradient(@angle, rgba(255,255,255,.15) 25%, transparent 25%, transparent 50%, rgba(255,255,255,.15) 50%, rgba(255,255,255,.15) 75%, transparent 75%, transparent);
    background-image: -ms-linear-gradient(@angle, rgba(255,255,255,.15) 25%, transparent 25%, transparent 50%, rgba(255,255,255,.15) 50%, rgba(255,255,255,.15) 75%, transparent 75%, transparent);
    background-image: -o-linear-gradient(@angle, rgba(255,255,255,.15) 25%, transparent 25%, transparent 50%, rgba(255,255,255,.15) 50%, rgba(255,255,255,.15) 75%, transparent 75%, transparent);
    background-image: linear-gradient(@angle, rgba(255,255,255,.15) 25%, transparent 25%, transparent 50%, rgba(255,255,255,.15) 50%, rgba(255,255,255,.15) 75%, transparent 75%, transparent);
  }
}
.reset-filter() {
  filter: e(%("progid:DXImageTransform.Microsoft.gradient(enabled = false)"));
}


.buttonBackground(@startColor, @endColor) {
  // gradientBar will set the background to a pleasing blend of these, to support IE<=9
  .gradientBar(@startColor, @endColor);
  .reset-filter();

  // in these cases the gradient won't cover the background, so we override
  &:hover, &:active, &.active, &.disabled, &[disabled] {
    background-color: @endColor;
  }

  // IE 7 + 8 can't handle box-shadow to show active, so we darken a bit ourselves
  &:active,
  &.active {
    background-color: darken(@endColor, 10%) e("\9");
  }
}

Component mixins

Popover arrows

For tipsies and popovers

#popoverArrow {
  .top(@arrowWidth: 5px) {
    bottom: 0;
    left: 50%;
    margin-left: -@arrowWidth;
    border-left: @arrowWidth solid transparent;
    border-right: @arrowWidth solid transparent;
    border-top: @arrowWidth solid @black;
  }
  .left(@arrowWidth: 5px) {
    top: 50%;
    right: 0;
    margin-top: -@arrowWidth;
    border-top: @arrowWidth solid transparent;
    border-bottom: @arrowWidth solid transparent;
    border-left: @arrowWidth solid @black;
  }
  .bottom(@arrowWidth: 5px) {
    top: 0;
    left: 50%;
    margin-left: -@arrowWidth;
    border-left: @arrowWidth solid transparent;
    border-right: @arrowWidth solid transparent;
    border-bottom: @arrowWidth solid @black;
  }
  .right(@arrowWidth: 5px) {
    top: 50%;
    left: 0;
    margin-top: -@arrowWidth;
    border-top: @arrowWidth solid transparent;
    border-bottom: @arrowWidth solid transparent;
    border-right: @arrowWidth solid @black;
  }
}