KNACSS/sass/utilities/_layout.scss

/* ----------------------------- */
/* ==Global Layout               */
/* ----------------------------- */

/* module, gains superpower "BFC" Block Formating Context */
.mod,
.bfc {
  overflow: hidden;
}

/* blocks that needs to be placed under floats */
.clear {
  clear: both;
}

/* blocks that must contain floats */
.clearfix {
  &::after {
    content: "";
    display: table;
    clear: both;
    border-collapse: collapse;
  }
}

/* simple blocks alignment */
.#{$kna-namespace}left {
  margin-right: auto;
}

.#{$kna-namespace}right {
  margin-left: auto;
}

.#{$kna-namespace}center {
  margin-left: auto;
  margin-right: auto;
}

/* text and contents alignment */
.#{$kna-namespace}txtleft {
  text-align: left;
}

.#{$kna-namespace}txtright {
  text-align: right;
}

.#{$kna-namespace}txtcenter {
  text-align: center;
}

/* floating elements */
.#{$kna-namespace}fl {
  float: left;
}

img.#{$kna-namespace}fl {
  margin-right: $small-value;
}

.#{$kna-namespace}fr {
  float: right;
}

img.#{$kna-namespace}fr {
  margin-left: $small-value;
}

img.#{$kna-namespace}fl,
img.#{$kna-namespace}fr {
  margin-bottom: $tiny-value;
}

/* inline-block */
.#{$kna-namespace}inbl {
  display: inline-block;
  vertical-align: top;
}

/* flexbox layout
http://www.alsacreations.com/tuto/lire/1493-css3-flexbox-layout-module.html
*/

[class*="#{$kna-namespace}flex-container"],
.#{$kna-namespace}flex-container,
.d-flex {
  display: flex;
  flex-wrap: wrap;
}

.#{$kna-namespace}flex-container-h,
.flex-row {
  flex-direction: row;
}

.#{$kna-namespace}flex-container-v,
.flex-column {
  flex-direction: column;
}

.#{$kna-namespace}flex-item-fluid {
  flex: 1;
  min-width: 0;
}

.#{$kna-namespace}flex-item-first,
.#{$kna-namespace}item-first {
  order: -1;
}

.#{$kna-namespace}flex-item-medium,
.#{$kna-namespace}item-medium {
  order: 0;
}

.#{$kna-namespace}flex-item-last,
.#{$kna-namespace}item-last {
  order: 1;
}

.#{$kna-namespace}flex-item-center,
.#{$kna-namespace}item-center,
.mr-auto {
  margin: auto;
}