.non-visible {
    display: none;
  }

.img-btn{
    margin: auto;
  }
.btn-box{
    display: flex; 
    margin-top: 10px;
}

mat-header-cell, mat-cell {
  justify-content: center;
}
mat-cell, mat-header-cell, mat-footer-cell {
  flex: 1;
  display: flex;
  align-items: center;
  overflow: initial;
  min-height: inherit;
}

  