<?php 
      $title = get_sub_field('title');
      $text = get_sub_field('text'); 
      $bg = get_sub_field('bg');     
?> 

<div class="container">
<div class="heroblock__hero card" <?php if($bg): ?> style="background-image: url(<?php echo($bg); ?>);" <?php endif; ?> >
    <div class="heroblock__hero_content">
    <?php if($title): ?><h1><?php echo esc_html($title); ?></h1> <?php endif ?> 
        <?php if($text): ?><?php echo esc_html(the_sub_field('text')); ?><?php endif ?> 
    </div>
</div> 
</div>