Essential basic knowledge and skills for learning CSS3

Essential basic knowledge and skills for learning CSS3

CSS3 refers to the third version of Cascading Style Sheets. It is an integral part of web design and is used to control the style and layout of web pages. CSS3 brings many new features and techniques to make our web pages more outstanding and professional. This article will introduce some basic knowledge and common techniques of CSS3, and illustrate it through code examples.

1. Selector

A selector is an identifier used to select elements in CSS. CSS3 introduces some new selectors to make selecting elements more flexible and precise. The following are some commonly used selector examples:

(1) Element selector: Select all specified elements. For example, select all paragraph elements:

p {
  color: red;
}

(2) Class selector: Select elements with specified class names. For example, select all elements with the class name "example":

.example {
  font-weight: bold;
}

(3) ID selector: Select the element with the specified ID. For example, select the element with the ID "header":

#header {
  background-color: blue;
}

(4) Attribute selector: Select the element with the specified attribute. For example, select all links with the "target" attribute:

a[target="_blank"] {
  text-decoration: underline;
}

2. Box model

The box model means that each element in the web page is treated as a rectangular box. Contains content, padding, borders, and margins. CSS3 allows us to have more control over the box model, making the page layout richer and more flexible. The following are some commonly used attributes and examples of the box model:

(1) Width and height:

.box {
  width: 200px;
  height: 100px;
}

(2) Padding:

.box {
  padding: 10px;
}

(3) Border:

.box {
  border: 1px solid black;
}

(4) Margins:

.box {
  margin: 20px;
}

3. Animation and transition

CSS3 provides rich animation and transition effects, making the page more vivid and interesting. By using keyframe animation and transition effects, we can achieve smooth transitions and dynamic changes in elements. The following are some commonly used animation and transition examples:

(1) Keyframe animation: Control the animation effect of elements by defining keyframes. For example, create an animation effect that moves from left to right:

@keyframes move {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(100px);
  }
}

.box {
  animation: move 2s infinite;
}

(2) Transition effect: By defining the initial state and terminal state of the element, a smooth transition effect is achieved. For example, create a color gradient transition effect:

.box {
  transition: background-color 1s;
}

.box:hover {
  background-color: red;
}

4. Responsive design

Responsive design means that the web page can automatically adapt to different devices and screen sizes. CSS3 provides some useful features that make it easy to implement responsive layout. Here are some commonly used responsive design techniques and examples:

(1) Media queries: By using media queries, we can apply different styles according to different screen sizes. For example, define an element that is hidden when the window width is less than 600 pixels:

@media screen and (max-width: 600px) {
  .box {
    display: none;
  }
}

(2) Flexible layout: By using flexible layout, we can automatically adjust the position and size of the element according to the size of the container. For example, create a horizontally centered layout:

.container {
  display: flex;
  justify-content: center;
  align-items: center;
}

The above are some essential basic knowledge and skills for learning CSS3. By learning and understanding this knowledge, we can better master CSS3 and create more beautiful and professional web pages. I hope this article will be helpful to your study!

Reference:

1. MDN Web Docs. "CSS Basic Concepts." (https://developer.mozilla.org/en-US/docs/Learn/Getting_started_with_the_web/CSS_basics )
2. CSS3.info. "CSS3 Box-Sizing Property." (https://www.css3.info/preview/box-sizing/)
3. W3Schools. "CSS3 Animations." (https://www.w3schools.com/css/css3_animations.asp)
4. CSS-Tricks. "A Comprehensive Guide to CSS Grids." (https://css-tricks.com/snippets/css /complete-guide-grid/)
5. Smashing Magazine. "How To Use CSS3 Media Queries To Create a Mobile Version of Your Website." (https://www.smashingmagazine.com/2010/07/how -to-use-css3-media-queries-to-create-a-mobile-version-of-your-website/)
6. CSS-Tricks. "Guide to Flexbox." (https://css -tricks.com/snippets/css/a-guide-to-flexbox/)

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