Use the :first-child pseudo-class selector to select the CSS style of the first child element

Use:first-child pseudo-class selector to select the CSS style of the first child element

The pseudo-class selector in CSS is a powerful tool. Specific elements can be selected and modified. Among them, the :first-child pseudo-class selector is a commonly used selector, which can select the first child element of an element, regardless of the type or position of the child element. In this article, we'll detail how to use the :first-child pseudo-class selector and provide some concrete code examples.

First, let’s look at a simple HTML code example:

<ul>
  <li>苹果</li>
  <li>香蕉</li>
  <li>橙子</li>
</ul>

In this example, we have an unordered list (ul) containing three list items (li) , respectively apples, bananas and oranges. Now, suppose we want to set the text color of the first list item (i.e. Apple) to red, we can use the :first-child pseudo-class selector to achieve this effect.

The following is a specific CSS code example:

ul li:first-child {
  color: red;
}

In this code, we use the :first-child pseudo-class selector to select the first li element under the ul element. Then, we set the text color of the selected element to red.

If we apply this CSS code to our example, the result will be that the font color of the first list item (apple) becomes red, while the other two list items (banana and orange) Keep the default colors.

Also, here's a more complex HTML example with multiple nested elements:

<div class="container">
  <h1 id="Hello-world">Hello, world!</h1>
  <p>Welcome to my website.</p>
  <ul>
    <li>苹果</li>
    <li>香蕉</li>
    <li>橙子</li>
  </ul>
</div>

If we want to select the first list item and set its text color to Red, we need to modify it slightly. Now, we need to select the first child element of the ul element using the :first-child pseudo-class selector and set its text color to red. The specific CSS code is as follows:

.container ul li:first-child {
  color: red;
}

In this code, we first select the ul element under the .container class, and then use the :first-child pseudo-class selector to select the first li element of the ul element. Finally, we set the text color of the selected element to red.

To summarize, by using the :first-child pseudo-class selector, we can easily select the first child element of an element and apply a specific CSS style to it. Whether it is a simple element or a complex nested structure, this selector can help us achieve the desired effect. I hope the code examples provided in this article are helpful to you.

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