Question

Can somebody please explain what the selectors mean?
As far as I understand having #myId – is css for control with id=myId.
.myClass is Css for controls with class myClass.
Can somebody please explain the other combinations?

div.img a:hover img
  {
  border:1px solid #0000ff;
  }
div.desc
  {
  text-align:center;
  font-weight:normal;
  width:120px;
  margin:2px;
  }

Answer 1

An id (#) can exist only once in a document. It is really useful to identify an element in CSS ans in JavaScript as well (should you ever need it).`

A class (.) can be used as often as it is required.

Example: you have only one header: <div id="header">Header</div>, but several articles: <div class="article">...</div>

---

Say you have this HTML document:

<div id="site">
    <h1>Some heading...</h1>
    <div class="article">
        <h1>Title</h1>
        <p>Some content...</p>
    </div>
    <div class="article">
        <h1>Title</h1>
        <p>Some content...</p>
    </div>
</div>

The heading of the articles shouldn’t be as big as the heading of the site, so we have to use a more specific selector: .article h1 {...}. This will style every <h1>element in a element of the class “article”.

If we want to have an even more specific selector, we would use: div.article h1 {...}. This will only style every <h1> element in a <div> box with the class “article”