Sergey

.content {
  border: 2px solid;
  padding: 3rem;
  
  display: flex;
  justify-content: space-around;
  flex-wrap: wrap;
}

.block1, .block2 {
  border: 1px solid blue;
}

Settings -> Editor -> General -> Appearance -> галочка "Enable HTML/XML tag tree highlighting

$(document).ready(function(){
    $('#mem').change(function(){
        if ( $(this).val() === '64GB' ) {
            $('.total-price-1').addClass('active');
            $('.total-price-2').removeClass('active');
        } else if ( $(this).val() === 'GB128' ) {
            $('.total-price-1').removeClass('active');
            $('.total-price-2').addClass('active');
        }
    });