CSS : 선택기 이해

# CSS: Understanding Selectors

CSS is a powerful tool for styling web pages. It allows developers to create visually appealing and responsive designs that enhance the user experience. One of the most important aspects of CSS is selectors. Selectors are used to target specific HTML elements and apply styles to them. In this blog post, we will dive deeper into understanding selectors in CSS.

What are Selectors?

Selectors are patterns used to select and style specific HTML elements. They are used to target elements based on their tag name, class name, ID, attributes, and more. Selectors are an essential part of CSS because they allow developers to apply styles to specific elements on a web page.

Types of Selectors

There are several types of selectors in CSS. Here are some of the most commonly used ones:

Tag Selectors

Tag selectors are used to target all elements of a specific tag. For example, the following code will apply styles to all <p> elements on a web page:

p {
  color: red;
}

Class Selectors

Class selectors are used to target elements with a specific class name. For example, the following code will apply styles to all elements with the class name "highlight":

.highlight {
  background-color: yellow;
}

ID Selectors

ID selectors are used to target elements with a specific ID. For example, the following code will apply styles to the element with the ID "header":

#header {
  font-size: 24px;
}

Attribute Selectors

Attribute selectors are used to target elements with a specific attribute. For example, the following code will apply styles to all elements with the "href" attribute:

a[href] {
  text-decoration: underline;
}

Pseudo-Selectors

Pseudo-selectors are used to target elements based on their state or position. For example, the following code will apply styles to all <a> elements when they are hovered over:

a:hover {
  color: blue;
}

Specificity

When multiple selectors target the same element, CSS uses specificity to determine which styles to apply. Specificity is a calculation based on the number of ID, class, and tag selectors used. ID selectors have the highest specificity, followed by class selectors, and then tag selectors.

For example, the following code will apply the styles defined in the .highlight class selector, even though the <p> tag selector is defined first:

p.highlight {
  background-color: yellow;
}

p {
  color: red;
}

Conclusion

Understanding selectors is essential for creating effective CSS styles. By using the right selectors, developers can target specific elements and apply styles that enhance the user experience. Remember to use tag, class, ID, attribute, and pseudo-selectors to create powerful and effective styles. Keep in mind the specificity of your selectors to ensure that your styles are applied correctly. With these tips, you'll be well on your way to creating beautiful and functional web pages with CSS.