From http://stackoverflow.com/questions/19695784/how-can-i-make-bootstrap-columns-all-the-same-height

bootstrap_equal_height.css

/** http://getbootstrap.com.vn/examples/equal-height-columns/ **/
/** http://getbootstrap.com.vn/examples/equal-height-columns/equal-height-columns.css **/

/*
 * Row with equal height columns
 * --------------------------------------------------
 */
.row-eq-height {
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display:         flex;
}

/*
 * Styles copied from the Grid example to make grid rows & columns visible.
 */
.container {
  padding-right: 15px;
  padding-left: 15px;
}

h4 {
  margin-top: 25px;
}
.row {
  margin-bottom: 20px;
}
.row .row {
  margin-top: 10px;
  margin-bottom: 0;
}
[class*="col-"] {
  padding-top: 15px;
  padding-bottom: 15px;
  background-color: #eee;
  background-color: rgba(86,61,124,.15);
  border: 1px solid #ddd;
  border: 1px solid rgba(86,61,124,.2);
}

/*
 * Callout styles copied from Bootstrap's main docs.
 */
/* Common styles for all types */
.bs-callout {
  padding: 20px;
  margin: 20px 0;
  border-left: 3px solid #eee;
}
.bs-callout h4 {
  margin-top: 0;
  margin-bottom: 5px;
}
.bs-callout p:last-child {
  margin-bottom: 0;
}
.bs-callout code {
  background-color: #fff;
  border-radius: 3px;
}
/* Variations */
.bs-callout-danger {
  background-color: #fdf7f7;
  border-color: #d9534f;
}
.bs-callout-danger h4 {
  color: #d9534f;
}
.bs-callout-warning {
  background-color: #fcf8f2;
  border-color: #f0ad4e;
}
.bs-callout-warning h4 {
  color: #f0ad4e;
}
.bs-callout-info {
  background-color: #f4f8fa;
  border-color: #5bc0de;
}
.bs-callout-info h4 {
  color: #5bc0de;
}

css_equal_height_flex.css

.row {
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display:         flex;
  flex-wrap: wrap;
}
.row > [class*='col-'] {
  display: flex;
  flex-direction: column;
}

css_equal_height_negative_margins.css

.row{
    overflow: hidden; 
}

[class*="col-"]{
    margin-bottom: -99999px;
    padding-bottom: 99999px;
}

css_equal_height_table.css

.row {
    display: table;
}

[class*="col-"] {
    float: none;
    display: table-cell;
    vertical-align: top;
}