style.scss

/*--------------------------------------------------------------
    style for WP Pagenavi plugin
--------------------------------------------------------------*/
.p-pagenavi {
  .wp-pagenavi {
    .page {
    }
    .previouspostslink {
    }
    .page.smaller {
    }
    .current {
    }
    .page.larger {
    }
    .nextpostslink {
    }
  }
}

wp-pagenavi.php

<div class="p-pagenavi">
<?php wp_pagenavi(); ?>
</div>