$headers-height: 24px;

.flex-grid {
  
  .headers {
    display: flex;
    text-align: center;
    height: $headers-height;
    position: absolute;
    
    .selection-mark {
      width: 3px;
      min-width: 3px;
      background-color: #e8e8e8;
      border-bottom: 2px solid #ccc;
    }
    
  }
}