Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.13)
// Compass (v1.0.3)
// ----

.form {
  color: black;
  
  &__label { font-weight: bold; }
  &__input {
    display: block;
    height: 34px;
    padding: 6px 12px;
    font-size: 14px;
    color: #555;
    // more styles
  }
}
 
 .form--participate {
   color: red;
   
    // any style modifications can go right inside this block
    .form {
      &__label { font-weight: normal; }
      &__input { height: 40px; }
    }
 }

SassMeister-output.css

.form {
  color: black;
}
.form__label {
  font-weight: bold;
}
.form__input {
  display: block;
  height: 34px;
  padding: 6px 12px;
  font-size: 14px;
  color: #555;
}

.form--participate {
  color: red;
}
.form--participate .form__label {
  font-weight: normal;
}
.form--participate .form__input {
  height: 40px;
}