fathom/assets/sass/_util.scss

.pull-right {
  float: right;
}

.pull-left {
  float: left;
}

.cf:before,
.cf:after {
    content: " "; /* 1 */
    display: table; /* 2 */
}

.cf:after {
    clear: both;
}

.small-margin {
  margin-top: 20px;
  margin-bottom: 20px;
}

.medium-margin {
  margin-top: 40px;
  margin-bottom: 40px;
}

.clear {
  clear: both;
}

.muted {
  color: #888;
}