Generated by SassMeister.com.

SassMeister-input-HTML.html

<section class="letter__b">
  
  <div class="letter__b__ascender">
    
  </div>
  
  <div class="letter__b__bowl">
    
  </div>
  
  <div class="letter__b--underscore">
    
  </div>
  
</section>

<h1>BEM</h1>

SassMeister-input.scss

// ----
// Sass (v3.3.9)
// Compass (v1.0.0.alpha.20)
// Flint (v1.6.1)
// ----

@import "compass";
@import "flint";

$flint__support-syntax: "BEM";

@include _(foundation);

.letter__b {
  @include _(container);
  
  &__ascender {
    @include _(4, $gutter: omega);
    background: black;
    height: 1000px;
  }
  
  &__bowl {
    @include border-top-right-radius(10em);
    @include border-bottom-right-radius(10em);
    @include _(7, $gutter: row);
    background: black;
    height: 700px;
    margin-top: 300px;
  }
  
  &--underscore {
    @include _(5, $gutter: alpha);
    background: black;
    height: 100px;
    margin-top: 1000px;
  }
}

h1 {
  font: 900 4em "Futura", "Helvetica Neue", Helvetica, Arial, sans-serif;
  margin-top: 0;
}

SassMeister-output.css

*, *:before, *:after {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}
.letter__b {
  display: block;
  float: none;
  max-width: 80em;
  margin-right: auto;
  margin-left: auto;
}
.letter__b__ascender {
  display: block;
  float: left;
  width: 96.875%;
  margin-right: 0;
  margin-left: 3.125%;
  background: black;
  height: 1000px;
}
@media only screen and (min-width: 60.0625em) {
  .letter__b__ascender {
    width: 24.21875%;
    margin-right: 0;
    margin-left: 0.78125%;
  }
}
@media only screen and (min-width: 40.0625em) and (max-width: 60em) {
  .letter__b__ascender {
    width: 32.29167%;
    margin-right: 0;
    margin-left: 1.04167%;
  }
}
@media only screen and (min-width: 20.0625em) and (max-width: 40em) {
  .letter__b__ascender {
    width: 48.4375%;
    margin-right: 0;
    margin-left: 1.5625%;
  }
}
.letter__b__bowl {
  -moz-border-radius-topright: 10em;
  -webkit-border-top-right-radius: 10em;
  border-top-right-radius: 10em;
  -moz-border-radius-bottomright: 10em;
  -webkit-border-bottom-right-radius: 10em;
  border-bottom-right-radius: 10em;
  display: block;
  float: left;
  width: 175%;
  margin-right: 0;
  margin-left: 0;
  background: black;
  height: 700px;
  margin-top: 300px;
}
@media only screen and (min-width: 60.0625em) {
  .letter__b__bowl {
    width: 43.75%;
    margin-right: 0;
    margin-left: 0;
  }
}
@media only screen and (min-width: 40.0625em) and (max-width: 60em) {
  .letter__b__bowl {
    width: 58.33333%;
    margin-right: 0;
    margin-left: 0;
  }
}
@media only screen and (min-width: 20.0625em) and (max-width: 40em) {
  .letter__b__bowl {
    width: 87.5%;
    margin-right: 0;
    margin-left: 0;
  }
}
.letter__b--underscore {
  display: block;
  float: left;
  width: 121.875%;
  margin-right: 3.125%;
  margin-left: 0;
  background: black;
  height: 100px;
  margin-top: 1000px;
}
@media only screen and (min-width: 60.0625em) {
  .letter__b--underscore {
    width: 30.46875%;
    margin-right: 0.78125%;
    margin-left: 0;
  }
}
@media only screen and (min-width: 40.0625em) and (max-width: 60em) {
  .letter__b--underscore {
    width: 40.625%;
    margin-right: 1.04167%;
    margin-left: 0;
  }
}
@media only screen and (min-width: 20.0625em) and (max-width: 40em) {
  .letter__b--underscore {
    width: 60.9375%;
    margin-right: 1.5625%;
    margin-left: 0;
  }
}

h1 {
  font: 900 4em "Futura", "Helvetica Neue", Helvetica, Arial, sans-serif;
  margin-top: 0;
}

SassMeister-rendered.html

<section class="letter__b">
  
  <div class="letter__b__ascender">
    
  </div>
  
  <div class="letter__b__bowl">
    
  </div>
  
  <div class="letter__b--underscore">
    
  </div>
  
</section>

<h1>BEM</h1>