apply css style for specific image banner in Dawn

I am using Dawn.

I want to assign a css rule only at single image banner in my home page.

In the home page I have many image banners but I want to apply the css rule only for one.

This is my solution, in the image_banner.liquid file

 <div {% if section.id == "template--14170940604549__image_banner" %} style="opacity: 0.85" {% endif %} class="banner__box color-{{ section.settings.color_scheme }}" >

There is a better way?