.underline {
  border-bottom: 2px solid currentColor;
}

.underline--blue {
  border-bottom-color: blue;
}

.underline--dotted {
  border-bottom: 3px red dashed;
}

// ----- Unrelated ----- //

html {
  $square-color: #eee;
  $square-size: 8px;
  line-height: 1;
  padding: 20px;
  background-image:
    linear-gradient(45deg, $square-color 25%, transparent 25%, transparent 75%, $square-color 75%, $square-color), 
    linear-gradient(45deg, $square-color 25%, transparent 25%, transparent 75%, $square-color 75%, $square-color);
  background-position: 0 0, $square-size $square-size;
  background-size: ($square-size * 2) ($square-size * 2);
  font-family: 'Source Sans Pro', sans-serif;
  font-size: 48px;
}

body {
  margin-left: auto;
  margin-right: auto;
  max-width: 600px;
}

p {
  line-height: 1;
  margin-bottom: 30px;
  margin-top: 0;
  
  &:last-child {
    margin-bottom: 0;
  }
}