change parent style on child hover code example

Example 1: styles for parent of selector

Short answer: no such selector exists. Use JavaScript
Long answer: by Kaotik below

Example 2: change parent div css on over of child

<ul id="main-menu">
  <li>
    <a href="#">
      <i class="fa fa-building-o" aria-hidden="true"></i>
      Private Limited
      <i class="fa fa-caret-down"></i>
    </a>
    <ul class="submenu">
      <li><a href="#0">Company</a>
      </li>
      <li><a href="#0">Contact</a>
      </li>
      <li><a href="#0">Industry</a>
      </li>
    </ul>
  </li>
</ul>

Example 3: hover on father elemet activates a child element css

/* EXAMPLE
projetos-hover is father; projetos-hover-text is the child
When hover on the father use ">" to aply on a child
*/

.projetos-hover-text {
  transform: translateY(-50%);
  transition: all 0.2s ease 0s;
}

.projetos-hover:hover > .projetos-hover-text {
  transform: translatey(+5%);
}