CSS Select the First Child from Elements with Particular Attribute

p[data-result="INVALID"] {  color: red}
p[data-result="INVALID"] ~ p[data-result="INVALID"] {    color: black;}

<p data-result="VALID"><b>Note:</b> a:active MUST come after a:hover in the CSS definition in order to be effective.</p><p data-result="INVALID"><b>Note:</b> a:hover MUST come after a:link and a:visited in the CSS definition in order to be effective.</p><p data-result="INVALID"><b>Note:</b> a:hover MUST come after a:link and a:visited in the CSS definition in order to be effective.</p>

Target first-child with css data attribute

Here you go man. Just the wrong css selector.

https://codepen.io/jackgisel/pen/dyPxrOG

[data-item="8"] p:first-of-type {
  ...
}

CSS selector for first element with class

This is one of the most well-known examples of authors misunderstanding how :first-child works. Introduced in CSS2, the :first-child pseudo-class represents the very first child of its parent. That's it. There's a very common misconception that it picks up whichever child element is the first to match the conditions specified by the rest of the compound selector. Due to the way selectors work (see here for an explanation), that is simply not true.

Selectors level 3 introduces a :first-of-type pseudo-class, which represents the first element among siblings of its element type. This answer explains, with illustrations, the difference between :first-child and :first-of-type. However, as with :first-child, it does not look at any other conditions or attributes. In HTML, the element type is represented by the tag name. In the question, that type is p.

Unfortunately, there is no similar :first-of-class pseudo-class for matching the first child element of a given class. At the time this answer was first posted, the newly published FPWD of Selectors level 4 introduced an :nth-match() pseudo-class, designed around existing selector mechanics as I mentioned in the first paragraph by adding a selector-list argument, through which you can supply the rest of the compound selector to get the desired filtering behavior. In recent years this functionality was subsumed into :nth-child() itself, with the selector list appearing as an optional second argument, to simplify things as well as averting the false impression that :nth-match() matched across the entire document (see the final note below).

While we await cross-browser support (seriously, it's been nearly 10 years, and there has only been a single implementation for the last 5 of those years), one workaround that Lea Verou and I developed independently (she did it first!) is to first apply your desired styles to all your elements with that class:

/* 
 * Select all .red children of .home, including the first one,
 * and give them a border.
 */
.home > .red {
    border: 1px solid red;
}

... then "undo" the styles for elements with the class that come after the first one, using the general sibling combinator ~ in an overriding rule:

/* 
 * Select all but the first .red child of .home,
 * and remove the border from the previous rule.
 */
.home > .red ~ .red {
    border: none;
}

Now only the first element with class="red" will have a border.

Here's an illustration of how the rules are applied:

.home > .red {
    border: 1px solid red;
}

.home > .red ~ .red {
    border: none;
}

<div class="home">
  <span>blah</span>         <!-- [1] -->
  <p class="red">first</p>  <!-- [2] -->
  <p class="red">second</p> <!-- [3] -->
  <p class="red">third</p>  <!-- [3] -->
  <p class="red">fourth</p> <!-- [3] -->
</div>

h3.r a[data-href="https://mail.google.com/"]

.page a:first-of-type{
    color:red;
}

div div {
    width: 50px;
    height: 50px;
    border: 1px solid black;
}

div[class*="recipes"] .header{
  margin-left: 40px;
}