trusted-setup-server/assets/styles/components/_icon.scss

.icon {
  background-position: center;
  background-repeat: no-repeat;
  background-size: contain;

  &-emoticon-sad {
    background-image: url('../img/icons/emoticon-sad.svg');
  }

  &.icon-48px {
    height: 48px;
    width: 48px;
  }

  &-twitter {
    background-image: url('../img/icons/tw.svg');
  }

  &-github {
    background-image: url('../img/icons/git.svg');
  }

  &-anonymous {
    background-image: url('../img/icons/anonymous.svg');
  }

  &-link {
    background-image: url('../img/icons/link.svg');
  }

  &-save {
    background-image: url('../img/icons/save.svg');
  }
}

.contribution-hash {
  .icon {
    background-image: url('../img/icons/copy.svg');
    background-size: 16px 16px;
  }
}