.box { 
    float: right; 
    height: 170px; 
    width: 250px; 
    color: white; 
    text-align: center; 
    padding: 20px; 
}

  .row:after {
    content: "";
    display: table;
    clear: both;
  }
  .row {
    display: flex;
  }
  
  .column {
    flex: 50%;
    float: left;
  }
  .column {
    float: left;
  }
  
  .btn_add {
    width:130px; 
    background-color: darkgreen; 
    color:white;
    height: 35px;
    border-radius: 5px;
  }
  
  .btn_search {
    width:30px; 
    background-color: white; 
    color:white;
    height: 35px;
  }

  .txt_search {
    /* width:100px;  */
    background-color: white; 
    color:black;
    height: 35px;
  }

  

  @media screen and (max-width: 600px) {
    .column {
      width: 100%;
    }
  }