.participants {
  margin: 25px 0;
  padding: 10px;
  width: 700px;
  background: #f3f3f3;
  border-top: 1px solid #ddd;
  border-bottom: 1px solid #ddd;
  list-style: none;
}

.participant {
  display: inline-block;
  margin-right: 10px;
}

#participants {
  margin-bottom: 10px;
  > ul {
    padding: 10px;
    width: $message-body-width;
    background: #f3f3f3;
    border-top: 1px solid #ddd;
    border-bottom: 1px solid #ddd;
    list-style: none;
    li {
      display: inline-block;
      margin-right: 10px;
    }
  }
}

.participants {
  margin: 25px 0;
  padding: 10px;
  width: 700px;
  background: #f3f3f3;
  border-top: 1px solid #ddd;
  border-bottom: 1px solid #ddd;
  list-style: none;
}

.participant {
  display: inline-block;
  margin-right: 10px;
}

Clean up participants component CSS
Clean up participants component CSS
