Generated by SassMeister.com.

SassMeister-input-HTML.html

<div class="avatar"></div>

SassMeister-input.scss

// ----
// Sass (v3.3.0.rc.5)
// Compass (v1.0.0.alpha.18)
// ----

.avatar {
  background-color: red;
  height: 120px;
  margin: 40px;
  width: 120px;
  
  @at-root {
    @keyframes fade {
      from { transform: scale(1.0); }
      to { transform: scale(1.1); }
    }
  }
  &:hover {
    animation: fade .4s infinite ease-in alternate;
  }
}

SassMeister-output.css

.avatar {
  background-color: red;
  height: 120px;
  margin: 40px;
  width: 120px;
}
@keyframes fade {
  from {
    transform: scale(1);
  }

  to {
    transform: scale(1.1);
  }
}
.avatar:hover {
  animation: fade .4s infinite ease-in alternate;
}

SassMeister-rendered.html

<div class="avatar"></div>