set style only for elements are inside a specific div - css

Question

I just wanna apply my custom style into the elements which are inside a specific div. I mean there are many elements with the same class all over the page and I want only apply these custom CSS to elements are inside a div with the data attr like div data-some-feature=... and not apply to the rest
<div class="row" data-language>
<section class="posts by-tags show-grid" data-language>
<div class='right a'>a</div>
<div class="row">';
<div class="col-xs-12 col-sm-12 col-md-12 col-lg-12 m-right">
<div class="a">
<h6>apple</h6>
<p>some text...</p>
</div>
</div>
</div>
</section>
</div>
<div class='row'>
<section .....>
......
</section>
</div>
<style>
div[data-dictionary-language].posts {
//some style
}
</style>
I want to use only div[data-dictionary-language] once and then apply my custom CSS like below:
<style>
div[data-dictionary-language]{
.tags{
//some style only apply to all elements are inside the specific div
}
.posts{
//some style only apply to all elements are inside the specific div
}
}
</style>

Answer 1

You were almost there, try like so:
/* ___________ select the div with data-language attribute
| ______ note the space here
| | ________ select child of div[data-language] with class posts
______|________ | __|__ */
div[data-language] .posts {
background-color: orange;
}
<div class="row" data-language>
<section class="posts by-tags show-grid" data-language>
<div class='right a'>a</div>
<div class="row">';
<div class="col-xs-12 col-sm-12 col-md-12 col-lg-12 m-right">
<div class="a">
<h6>apple</h6>
<p>some text...</p>
</div>
</div>
</div>
</section>
</div>
<div class='row'>
<section .....>
......
</section>
</div>