Css :first-letter not working

Identifying suitable elements

Remember, for ::first-letter to work, your targeted HTML element must be a block-level container. Typical block elements include <p>, <div>, <h1> to <h6>, <li>, etc.

/* Sherlock Holmes of HTML, elementary my dear Watson */
.block-element::first-letter {
  font-size: larger;
}


Don't apply ::first-letter to inline elements like <span> or <a> expecting it to work. If you still prefer using an inline element, set its display property to block or inline-block.

/* Doc says, "I'm in block now, feeling dizzy" */
.inline-element {
  display: block;
}


Paying attention to the first content

This pseudo-element will skip any non-letter content or tags that precede the first-letter. So, you might want to avoid preceding the ::first-letter with a space, punctuation, or tag.

/* "Hey, is it a bird? ...No, it's just a space!" */
.element::first-letter {
  background-color: yellow;
}


Addressing :before pseudo-element

If you used :before to bring about some content and you want to ::first-letter to point to the actual text instead of the introduced content, navigate carefully.

/* Wink wink, I came before everything eh! */
.element:before {
  content: "★";
}
    
.element::first-letter {
  font-size: 200%;
  color: orange;
}


In this case, since before is applied, your ::first-letter is actually the first star (★), not the first letter of your .element text.

Understanding pseudo-class concept

The ::first-letter selector is a pseudo-element which can be seen as a specific type of pseudo-class. They style specific parts of elements, thus adding more precision to your CSS.

/* "I know Kung-Fu. And by Kung-Fu, I mean styling" */
.kung-fu-class::first-letter {
  text-transform: uppercase;
}


Balancing style and compatibility

A critical aspect is the element and its compatibility. The wrong combination can mean ::first-letter won't have any effect. Make sure to use :: for modern browsers and : for broader, older browser compatibility.

When using ::first-letter, also keep typography in mind. Too much styling might interfere with your overall design.

Navigating through reliable reference

Whether you're an experienced coder looking for an argument on the behavior of ::first-letter or a beginner who wants more examples and in-depth exploration, I strongly recommend the MDN documentation.