.email-item {
  border: 1px solid #ddd;
  padding: 10px;
  margin-bottom: 10px;
  position: relative;
  }

  .email-item .email-index {
      position: absolute;
      top: 10px;
      left: 10px;
      background: #000;
      color: #fff;
      border-radius: 50%;
      width: 25px;
      height: 25px;
      display: flex;
      align-items: center;
      justify-content: center;
  }

  .highlight {
      background-color: yellow;
  }