Friday, 29 March 2019

HTML Styles - CSS

HTML Styles - CSS


Styling HTML with CSS

CSS stands for Cascading Style Sheets.
CSS describes how HTML elements are to be displayed on screen, paper, or in other media.
CSS saves a lot of work. It can control the layout of multiple web pages all at once.
CSS can be added to HTML elements in 3 ways:
  • Inline - by using the style attribute in HTML elements
  • Internal - by using a <style> element in the <head> section
  • External - by using an external CSS file
The most common way to add CSS, is to keep the styles in separate CSS files. However, here we will use inline and internal styling, because this is easier to demonstrate, and easier for you to try it yourself.



Inline CSS

An inline CSS is used to apply a unique style to a single HTML element.
An inline CSS uses the style attribute of an HTML element.
This example sets the text color of the <h1> element to blue:

<h1 style="color:blue;">This is a Blue Heading</h1>

Internal CSS

An internal CSS is used to define a style for a single HTML page.
An internal CSS is defined in the <head> section of an HTML page, within a <style> element:

  <!DOCTYPE html>                                 
   <html>                                                
   <head>                                                 
   <style>                                                 
   body {background-color: powderblue;}  
   h1   {color: blue;}                                
   p    {color: red;}</style>                     
   </head>                                                      
   <body>                                                         

   <h1>This is a heading</h1>                         
   <p>This is a paragraph.</p>                         

   </body>                                                           
   </html>                                                            

External CSS

An external style sheet is used to define the style for many HTML pages.
With an external style sheet, you can change the look of an entire web site, by changing one file!
To use an external style sheet, add a link to it in the <head> section of the HTML page:

<!DOCTYPE html>                               
<html>                                        
<head>                                        
  <link rel="stylesheet" href="styles.css">   
</head>                                       
<body>                                        

<h1>This is a heading</h1>                    
<p>This is a paragraph.</p>                   

</body>                                       
</html>                                       

An external style sheet can be written in any text editor. The file must not contain any HTML code, and must be saved with a .css extension.


Here is how the "styles.css" looks:

body {
  background-color: powderblue;
}

h1 {
  color: blue;
}

{
  color: red;
}

CSS Fonts

The CSS color property defines the text color to be used.
The CSS font-family property defines the font to be used.
The CSS font-size property defines the text size to be used.

<!DOCTYPE html>
<html>
<head>
<style>
h1 {
  color: blue;
  font-family: verdana;
  font-size: 300%;
}
p  {
  color: red;
  font-family: courier;
  font-size: 160%;
}
</style>

</head>
<body>

<h1>This is a heading</h1>
<p>This is a paragraph.</p>

</body>
</html>

CSS Border

The CSS border property defines a border around an HTML element:

{
  border: 1px solid powderblue;
}

CSS Padding

The CSS padding property defines a padding (space) between the text and the border:

{
  border: 1px solid powderblue;
  padding: 30px;
}

CSS Margin

The CSS margin property defines a margin (space) outside the border:

{
  border: 1px solid powderblue;
  margin: 50px;
}

The id Attribute

To define a specific style for one special element, add an id attribute to the element:

<p id="p01">I am different</p>

then define a style for the element with the specific id:

#p01 {
  color: blue;
}

Note: The id of an element should be unique within a page, so the id selector is used to select one unique element!

The class Attribute

To define a style for special types of elements, add a class attribute to the element:

<p class="error">I am different</p>

then define a style for the elements with the specific class:

p.error {
  color: red;
}

External References

External style sheets can be referenced with a full URL or with a path relative to the current web page.
This example uses a full URL to link to a style sheet:

<link rel="stylesheet" href="https://www.w3schools.com/html/styles.css">

This example links to a style sheet located in the html folder on the current web site:

<link rel="stylesheet" href="/html/styles.css">


This example links to a style sheet located in the same folder as the current page:

<link rel="stylesheet" href="styles.css">



Chapter Summary

  • Use the HTML style attribute for inline styling
  • Use the HTML <style> element to define internal CSS
  • Use the HTML <link> element to refer to an external CSS file
  • Use the HTML <head> element to store <style> and <link> elements
  • Use the CSS color property for text colors
  • Use the CSS font-family property for text fonts
  • Use the CSS font-size property for text sizes
  • Use the CSS border property for borders
  • Use the CSS padding property for space inside the border
  • Use the CSS margin property for space outside the border

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