Generated by SassMeister.com.

SassMeister-input-HTML.haml

%span.required.angle
    %input

SassMeister-input.sass

// ----
// Sass (v3.3.0.rc.1)
// Compass (v0.13.alpha.10)
// ----

$red: red

.required.angle
  position: absolute
  width: 0
  height: 0
  right: 3px
  top: 3px
  border-top: 20px solid $red
  border-left: 20px solid transparent

SassMeister-output.css

.required.angle {
  position: absolute;
  width: 0;
  height: 0;
  right: 3px;
  top: 3px;
  border-top: 20px solid red;
  border-left: 20px solid transparent;
}

SassMeister-rendered.html

<span class='required angle'>
  <input>
</span>