端の丸いBorder ref: http://qiita.com/gatespace/items/962d8a97555c401ccf0e

round-cap-border.scss

$width__border: 6px;
$color__border: red;
h1 {
  font-size: 18px;
  border-left-style: solid;
  border-left-width: $width__border;
  border-left-color: $color__border;
  position: relative;
  padding-left: 10px;
  &:before,
  &:after {
    content: ' ';
    background-color: $color__border;
    width: $width__border;
    height: $width__border;
    border-radius: ($width__border/2);
    display: block;
    position: absolute;
    left: -($width__border);
  }
  &:before {
    top: -($width__border/2);
  }
  &:after {
    bottom: -($width__border/2);
  }
}