Basics of web design

Teacher  Juan Romero Luis

Mar 3, 2025

Unit 4

Front-end layout
CSS3 (I)

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Introduction to CSS

N

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Introduction to CSS

What is CSS?

Is CSS a programming language?

CSS, or Cascading Style Sheets, is not a programming language, but a style sheet language used for describing the look and formatting of a document written in HTML.

Introduction to CSS

CSS ruleset

p {
 
color: red; 

}

Selector

Property

Property value

Declaration

Introduction to CSS

CSS ruleset

p { 
color: blue;
line-height: 1.5;
font-size: 14px; 
}

Introduction to CSS

CSS ruleset

h1, h2, h3 { 
color: purple; 
text-align: center; 
}

Introduction to CSS

How to make CSS work in our HTML pages

Inline

Internal

External

Introduction to CSS

How to make CSS work in our HTML pages

👉

Inline

<p style="color: red;">This is an example of inline CSS.</p>

p {
color: red; 
}

page.html

Introduction to CSS

How to make CSS work in our HTML pages

👉

Internal

<!DOCTYPE html>
<html>
	<head>
	  <style>
	    p {
	      color: red;
	    }
	  </style>
	</head>
	<body>
    <!-- The content of the document... -->
	</body>
</html>

page.html

Introduction to CSS

How to make CSS work in our HTML pages

👉

External

<!DOCTYPE html>
<html>
	<head>
	   <link rel="stylesheet" type="text/css" href="styles.css">
	</head>
	<body>
	   <!-- The content of the document... -->
	</body>
</html>

page.html

p {
  color: red;
}

styles.css

Basics of web design

Teacher  Juan Romero Luis

Mar 4, 2025

Unit 4

Front-end layout
CSS3 (II)

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One

Three

Two

Pop Quiz!!

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Review QU4.1
Review about the basics of CSS

Commenting in CSS

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Commenting in CSS

CSS commenting syntax

/* This is a comment */ 
  p 
   { 
    color: red; 
   }  

The DOM structure

The DOM structure

<!DOCTYPE html>
<html>
  <head>
    <title>My First Website</title>
  </head>
  <body>
    <h1>Welcome to my website!</h1>
    <p>This is a paragraph.</p>
  </body>
</html>
  • The <html> element is the root of the tree.
  • The <head> and <body> elements are children of the <html> element.
  • The <title> element is a child of the <head> element and grandchild of <html>.
  • The <h1> and <p> elements are children of the <body> element and grandchildren of <html>.

Types of selectos

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Types of selectos

Element selector

p { 
color: blue;
line-height: 1.5;
font-size: 14px; 
}
h1, div, quote { 
text-align: center; 
}

Types of selectos

Class selector

This selector is used to select a group of elements that have a specific class attribute.

<!DOCTYPE html>
<html>
	<head>
	   <link rel="stylesheet" type="text/css" href="styles.css">
	</head>
	<body>
		<p class="name-class">This is a paragraph.</p>
		<blockquote class="name-class"> This is a blockquote. </blockquote>
	</body>
</html>

page.html

.name-class {
  color: red;
}

styles.css

<!DOCTYPE html>
<html>
	<head>
	   <link rel="stylesheet" type="text/css" href="styles.css">
	</head>
	<body>
		<p class="name-class">This is a paragraph.</p>
		<blockquote class="name-class"> This is a blockquote. </blockquote>
	</body>
</html>

page.html

p.name-class {
  color: red;
}

styles.css

Types of selector

Class selector

👉

Class selector with an element

Types of selectos

ID selector

This selector is used to select a specific element with a certain ID.

<!DOCTYPE html>
<html>
	<head>
	   <link rel="stylesheet" type="text/css" href="styles.css">
	</head>
	<body>
    	<h1 id="name-id"> Title </h1>
		<p class="name-class">This is a paragraph.</p>
		<blockquote class="name-class"> This is a blockquote. </blockquote>
	</body>
</html>
#name-id {
  text-align: center;
}

styles.css

page.html

Types of selectos

Attribute selector

It is used to select elements with certain attributes or attribute values. 

<!DOCTYPE html>
<html>
	<head>
	   <link rel="stylesheet" type="text/css" href="styles.css">
	</head>
	<body>
		<p>This is a<a href="https://www.facebook.com" target="_blank"> link.</a></p>
	</body>
</html>
a[target="_blank"], a[href="https://example.com"] 
	{
 	 background-color: lightgray;
	}

styles.css

page.html

Basics of web design

Teacher  Juan Romero Luis

Mar 10, 2025

Unit 4

Front-end layout
CSS3 (III)

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One

Three

Two

Pop Quiz!!

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QU4.1b 
Review elements, id, class and pseudo-classes.

Types of selectors

Pseudo-classes in CSS

  selector:pseudo-class 
   { 
    property: value; 
   }  

Pseudo-classes in CSS are used to define a special state of an element.

Types of selectors

Pseudo-classes in CSS

👉

:link

a:link {
  color: blue;
}

is used to select links that the user has not yet visited.

Types of selectors

Pseudo-classes in CSS

👉

:visited

a:visited {
  color: purple;
}

is used to select links that the user has already visited.

Types of selectors

Pseudo-classes in CSS

👉

:hover

div:hover {
  color: red;
}

is used to select an element when the user's pointer is over it.

a:hover {
  color: purple;
}
button:hover {
  color: purple;
}

Types of selectors

Pseudo-classes in CSS

👉

:avtive

is used to select an element at the moment it is being activated
(like when a button is being clicked).

button:active {
  background-color: green;
}

Types of selectors

Pseudo-classes in CSS

👉

:focus

is used to select an element when it has focus. This is often used to add special styles to form elements when they are being interacted with by the user.

input:focus {
  border: 2px solid blue;
}

Live example.

Types of selectors

Pseudo-classes in CSS

👉

:first-child

is used to select the first child element inside a parent element.

ul li:first-child {
  color: red;
}
p i:first-child {
  color: blue;
}

Types of selectors

Pseudo-classes in CSS

👉

:last-child

is used to select the last child element inside a parent element.

ul li:last-child {
  color: green;
}
p i:last-child {
  color: blue;
}

Basics of web design

Teacher  Juan Romero Luis

Mar 11, 2025

Unit 4

Front-end layout
CSS3 (IV)

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Review

Class

ID

Pseudo-class

.wtf {
  color: red;
}

HTML element

p {
  color: red;
}  
#wtf {
  color: red;
}
a:hover {
  color: red;
}

Types of selectors

Pseudo-elements in CSS

  selector::pseudo-element
   { 
    property: value; 
   }  

Pseudo-elements in CSS are used to style certain parts of an element.

Types of selectors

Pseudo-elements in CSS

👉

::first-line

p::first-line {
  color: blue;
  text-transform: uppercase;
}

is used to style the first line of a block-level element.

Types of selectors

Pseudo-elements in CSS

👉

::first-letter

p::first-letter {
  color: red;
  font-size: 40px;
}

is used to style the first letter of a block-level element.

Types of selectors

Pseudo-elements in CSS

👉

::before   &   ::after

p::before {
  content: "Read this - ";
  color: green;
}

are used to insert content before or after an element's content.

p::after {
  content: " - Thank you!";
  color: green;
}

Types of selectors

Pseudo-elements in CSS

👉

::selection

p::selection {
  background: yellow;
  color: black;
}

is used to style a section of an element that has been selected by a user.

Types of selectors

Pseudo-elements in CSS

👉

::marker

li::marker {
  color: green;
  content: "> ";
}

 is used to style the bullet points in a list.

Basics of web design

Teacher  Juan Romero Luis

Mar 17, 2025

Unit 4

Front-end layout
CSS3 (V)

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One

Three

Two

Pop Quiz!!

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Review QU4.3. 
Review Pseudo-elements and more

Selector combinations

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Selector combination

Descendant combinator

is used to select elements that are descendants of a specific element.

div p {
  color: blue;
}

Selector combination

Child Combinator

is used to select elements that are direct children of a specific element.

div > p {
  color: green;
}

Differences between descendant and child combinator

Selector combination

Next-sibling combinator

 is used to select an element that is the immediate sibling following another element.

p + p {
  color: green;
}

Basics of web design

Teacher  Juan Romero Luis

Mar 18, 2025

Unit 4

Front-end layout
CSS3 (VI)

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One

Three

Two

Pop Quiz!!

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Review QU4.4. 
Review about combinators in CSS

Specificity in CSS

Specificity in CSS​

is a scoring system that determines which style rules are applied to an element when there is a conflict between CSS rules. Each type of selector has a different point value:

Universal selectors (*)

Regular elements (HTML), or pseudo-elements

Inline styles

Classes, pseudo-classes, or attributes

!important rule

ID selectors

Specificity in CSS​

In terms of CSS imports, the following order is applied:

Inline stye

Internal style

External style

Specificity in CSS​

Who is winning?

Specificity in CSS

🎯 Activity: Work on your projects (30 min)

Basics of web design

Teacher  Juan Romero Luis

Mar 24, 2025

Unit 4

Front-end layout
CSS3 (VII)

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One

Three

Two

Pop Quiz!!

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Review QU4.5. 
Review about specificity in CSS

The box model

The box model

Content

Padding

Boroder

Margin

The box model

Content

Padding

Boroder

Margin

p {

    width: 300px;

    height: 200px;

    padding: 20px;

    border: 20px, solid, white;

    margin: 20px;

}

The box model

<!DOCTYPE html>
<html lang="en-US">
  <head>
    <style>
      .box {
        width: 200px;
        height: 200px;
        border: 2px solid black;
        margin: 10px;
        padding: 20px;
        text-align: center;
      }
    </style>
  </head>
  <body>
    <div class="box">This is a box.</div>
  </body>
</html>

🎯 Step by step activity. Be quite and pay attention to your teacher.

The box model

Padding

Shortcut

div {
  padding-top: 50px;
  padding-right: 30px;
  padding-bottom: 50px;
  padding-left: 80px;
}

Regular

div {
  padding: 25px 50px 75px 100px;
}

The box model

Padding

The box model

Margin

Shortcut

div {
  margin-top: 20px;
  margin-right: 30px;
  margin-bottom: 20px;
  margin-left: 30px;
}

Regular

div {
  margin: 20px 30px 20px 30px;
}

The box model

Margin

Basics of web design

Teacher  Juan Romero Luis

Mar 31, 2025

Unit 4

Front-end layout
CSS3 (VIII)

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Fonts in CSS

Border values

Shortcut

div {
  border-width: 5px;
  border-style: solid;
  border-color: red;
}

Regular

div {
  border: 5px solid red;
}

The box model

Border values

div {
  border-top: 5px solid red;
  border-right: 10px dotted green;
  border-bottom: 5px dashed blue;
  border-left: 10px double purple;
}

The box model

CSS height and width (values)

div {
    height: 100px;
    width: 50%;
}

auto

 The browser calculates the height. This is the default value.
length Defines the height in px, cm, etc.
% Defines the height in percent of the containing block
initial Sets the height to its default value
inherit The height will be inherited from its parent element

The box model

CSS height and width (properties)

div {
    width: 100%;
    max-width: 900px;
}
height Sets the height of an element
max-height Sets the maximum height of an element
max-width Sets the maximum width of an element
min-height Sets the minimum height of an element
min-width Sets the minimum width of an element
width Sets the width of an element

Basics of web design

Teacher  Juan Romero Luis

Apr 1, 2025

Unit 4

Front-end layout
CSS3 (IX)

bit.ly/BWD25U4

CSS units

CSS units

Absolute lengths

cm centimeters
mm millimeters
in inches (1in = 96px = 2.54cm)
px* pixels (1px = 1/96th of 1in)
pt points (1pt = 1/72 of 1in)
pc picas (1pc = 12 pt)

*Pixels (px) are relative to the viewing device. On low-dpi devices, 1px represents one device pixel (dot) of the display.

⚠️ Decimal number with period

In absolute lengths, the decimal number is represented by a point, not a comma.

CSS units

Relative lengths

👉

em

body {
  font-size: 16px;
}

div {
  font-size: 1.5em; /* 24px */
}

unit is relative to the font-size of its closest parent.

CSS units

Relative lengths

👉

rem

body {
  font-size: 16px; /* 1rem = 16px */
}

h1 {
  font-size: 2em; /* 2em = 2x16px = 32px */
}

p {
  font-size: 1em; /* 1em = 1x16px = 16px */
  line-height: 1.5rem; /* 1.5rem = 1.5x16px = 24px */
}

 (root em) is also elative to the font-size, but unlike 'em', it's relative to the root, or the html element, not the parent.

CSS units

Relative lengths

👉

vw

div {
  width: 50vw; /* The div will take up 50% of the viewport's width. */
}

unit stands for viewport width. It's a relative unit that represents 1% of the width of the viewport.

⚠️ The viewport

The term 'viewport' refers to the size of the browser window.

CSS units

Relative lengths

👉

vh

div {
  height: 70vh; /* The div will take up 70% of the viewport's height. */
}

unit stands for viewport height. Similar to 'vw', it's a relative unit that represents 1% of the height of the viewport.

Document website structure

Document website structure

Document web structure

Header

is typically a large strip at the top of the page featuring a prominent heading, logo, and possibly a tagline. 

<!DOCTYPE html>
<html lang="en-US">
  <head>
  </head>
  <body>
    <header>
      <h1>Header</h1>
    </header>
  </body>

Document web structure

Navigation Bar

links to the main sections of the site, usually represented by menu buttons or tabs. It does need to be in the header, it can be a separate component.

  <body>
    <header>
    	<nav>
          <ul>
            <li><a href="#">Home</a></li>
            <li><a href="#">Our team</a></li>
            <li><a href="#">Projects</a></li>
            <li><a href="#">Contact</a></li>
          </ul>
    	</nav>
    </header>
  </body>

Document web structure

Main content

is a large central area containing the unique content of a given webpage.

  <body>
    <header>
    	<nav>
          <ul>
            <li><a href="#">Home</a></li>
            <li><a href="#">Our team</a></li>
            <li><a href="#">Projects</a></li>
            <li><a href="#">Contact</a></li>
          </ul>
    	</nav>
    </header>
    <main>
      <section>
      	<h2> Content of the section </h2>
      </section>
    </main>
  </body>

⚠️ The main content is typically divided into various content subsections, represented by <article>, <section>, and <div> elements.

Document web structure

Sidebar

includes peripheral information, links, quotes, ads, etc., often contextually related to the main content.

  <body>
    <main>
      <section>
      	<h2> Content of the section </h2>
      </section>
      <aside>
     	 <ul>
            <li><a href="#">About us</a></li>
            <li><a href="#">Our team</a></li>
            <li><a href="#">Projects</a></li>
            <li><a href="#">Contact</a></li>
         </ul>
      </aside>
    </main>
  </body>

Document web structure

Footer

is a strip at the bottom of the page, usually containing fine print, copyright notices, or contact information.

  <body>
    <main>
		...
    </main>
    <footer>
          <p>©Copyright 2050 by nobody. All rights reversed.</p>
    </footer>
  </body>

Document website structure

Basics of web design

Teacher  Juan Romero Luis

Apr 7, 2025

Unit 4

Front-end layout
CSS3 (X)

bit.ly/BWD24U4

One

Three

Two

PopQUiz!!

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Review QU4.6. 
Review about the box model

Fonts in CSS

Fonts in CSS

link method

<head>
  <link href="URL" rel="stylesheet">
</head>
body {
  font-family: "Font name", sans-serif;
}

Fonts in CSS

@import method

/*CSS stylesheet*/
@import url('URL');

body {
  font-family: "Font family", sans-serif;
}

Fonts in CSS

Google Fonts