CSS

Cascading Style Sheets

Add Some Style

Dr. Daniel Kelly

with CSS

"nouns" and "adjectives"

no CSS

only "nouns"

with CSS

"nouns" and "adjectives"

no CSS

only "nouns"

Zen Garden 1

Zen Garden 2

Zen Garden 3

HTML Box

A helpful way to understand CSS is to imagine a box surrounding every HTML element

<body>
    <h1>Far Far Away</h1>

    <p>Far far away, <em>behind the word mountains</em>, far from the 
    countries Vokalia and Consonantia, there live the blind texts. 
    Separated they live in Bookmarksgrove right at the coast of the 
    Semantics, a large language ocean. A small river named Duden flows 
    by their place and supplies it with the necessary regelialia.</p>

    <p>It is a paradisematic country, in which roasted parts of sentences
     fly into your mouth. Even the all-powerful <strong>Pointing</strong> 
    has no control about the blind texts it is an almost unorthographic life. 
    One day however a small line of blind text by the name of Lorem Ipsum 
    decided to leave for the far World of Grammar.</p>

    <p>The Big Oxmox advised her not to do so, because there were thousands of 
    bad Commas, wild Question Marks and devious Semikoli, but the 
    <strong>Little Blind Text</strong> didn’t listen. She packed her seven versalia, 
    put her initial into the belt and made herself on the way.</p>
</body>

: Block Level Element

: Inline Element

HTML Box

CSS allows us to create rules that control the way each individual box (and contents) is presented

<body>
    <h1>Far Far Away</h1>

    <p>Far far away, <em>behind the word mountains</em>, far from the 
    countries Vokalia and Consonantia, there live the blind texts. 
    Separated they live in Bookmarksgrove right at the coast of the 
    Semantics, a large language ocean. A small river named Duden flows 
    by their place and supplies it with the necessary regelialia.</p>

    <p>It is a paradisematic country, in which roasted parts of sentences
     fly into your mouth. Even the all-powerful <strong>Pointing</strong> 
    has no control about the blind texts it is an almost unorthographic life. 
    One day however a small line of blind text by the name of Lorem Ipsum 
    decided to leave for the far World of Grammar.</p>

    <p>The Big Oxmox advised her not to do so, because there were thousands of 
    bad Commas, wild Question Marks and devious Semikoli, but the 
    <strong>Little Blind Text</strong> didn’t listen. She packed her seven versalia, 
    put her initial into the belt and made herself on the way.</p>
</body>

CSS General Structure

selector
{
    property: value;
}

selector

property

: selects existing HTML

: applies style to selected HTML

CSS General Structure

h1
{
    color: pink;
}

Changes color text for all h1's to pink

CSS General Structure

selector
{
    property: value1;
    anotherproperty: value2;
}

Change style of multiple aspects of element at once

CSS General Structure

p
{
    color: red;
    background-color: blue;
}

Change text color to red and background color to blue for all <p> elements

CSS Simple Examples

/*Make all h1's in the html purple and 50px font*/
h1{
    color: purple;
    font-size: 50px;
}

/*Make all img's in the html have 2px red border*/
img{
    border-color: red;
    border-size: 2px;
}

<link>: Joining HTML and CSS

<!DOCTYPE html>
<html>
<head>
	<title>CSS Demo</title>
	<link rel="stylesheet" type="text/css" href="myfirststyle.css">
</head>
<body>

	<h1>Heading here</h1>

	<h4>Sub-heading here</h4>

	<p>Body text here.</p>

</body>
</html>

myhtmlfile.html:

myfirststyle.css:

h1{
    color: red;
}

h4{
    color: green;
}

Result on Browser:

CSS General Structure

css1

Colour

Color in CSS

Built in Colors

h1
{
    color: red;
}

h2
{
    color: green;
}

Built in Colors specified by word
Approx 200 built in Colors
- See here

Text Color

h1
{
    color: red;
}

Color in CSS

Hexadecimal Colors

h1
{
    color: #000000;
}

h2
{
    color: #FF1493;
}

# + String of 6 hexademical numbers
Approx 6,777,216 colors

#000000

Hexadecimal Colors

#000000

Color in CSS

RGB Colors

h1
{
    color: rgb(0, 255, 0);
}

h2
{
    color: rgb(10, 99, 150);
}

3 Channels: 0-255
- Red
- Green
- Blue
Approx 6,777,216 colors

Color in CSS

RGBA Colors

h1
{
    color: rgba(0, 255, 0, 1);
}

h2
{
    color: rgba(10, 99, 150,.3);
}

4 Channels:
- Red: 0-255
- Green: 0-255
- Blue: 0-255
- Alpha (transparency): 0-1
  - 0: Fully Transparent
  - 1: Fully Opaque

cssColor

Background

background : sets the color of background

color : sets the color of text

body{
    background: #b5cece;
}

div{
    background: #6ac9c9;
}

p{
    color: #1b3333;
}

<body>
    <div>
	<p>Introduction section goes here</p>
	<p>Main body section goes here</p>
	<p>Conclusion section goes here</p>
    </div>
</body>

cssBackground

Color Contrast

Foreground and Background should be chosen to ensure there is enough contrast for the text to be legible

Color Pallets

Use Colors that Complement Each Other

Warm and Cool

Bright Accent Colors

Bright Accent Colors

Minimalist mixed with Striking color

Minimalist mixed with Striking color

Color Pallets

Use Colors that Complement Each Other

Pallet Generator

basicCSSColour

Background Image

body{
    background-image: url(addressOfImageFile.jpg);
}

Background Image

body{
    background-image: url(computer-wallpaper-5.jpg);
}

div{
    background: #6ac9c9;
}

p{
    color: #1b3333;
}

<body>
    <div>
	<p>Introduction section goes here</p>
	<p>Main body section goes here</p>
	<p>Conclusion section goes here</p>
    </div>
</body>

Exercise:

In Visual Studio Code, create a simple html page with a h1, h4 and p tags (enter some dummy text)
Create a css file and set the following text colors:
- h1: #119DA4
- h4: #80DED9
- p: #AEECEF
Link the html file to the css file
Test in the browser
Set the background image to the following:
- https://i.imgur.com/SPZdXnP.png

<!DOCTYPE html>
<html>
<head>
    <title></title>
    <link rel="stylesheet" type="text/css" href="mystlye.css">
</head>
<body>
    
</body>
</html>

Exercise:

<!DOCTYPE html>
<html>
<head>
    <title></title>
    <link rel="stylesheet" type="text/css" href="bg.css">
</head>
<body>
    <h1>Heading</h1>

    <h4>Sub heading</h4>

    <p>Main text here</p>
</body>
</html>

body{
    background-image: url(https://i.imgur.com/SPZdXnP.png);
}

h1{
    color: #119DA4;
}

h4{
    color: #80DED9;
}

p{
    color: #AEECEF;
}

Exercise:

<!DOCTYPE html>
<html>
<head>
    <title></title>
    <link rel="stylesheet" type="text/css" href="bg.css">
</head>
<body>
    <h1>Heading</h1>

    <h4>Sub heading</h4>

    <p>Main text here</p>
</body>
</html>

body{
    background: url(https://i.imgur.com/SPZdXnP.png);
    background-repeat: no-repeat;
}

h1{
    color: #119DA4;
}

h4{
    color: #80DED9;
}

p{
    color: #AEECEF;
}

background-repeat: no-repeat;

Exercise:

<!DOCTYPE html>
<html>
<head>
    <title></title>
    <link rel="stylesheet" type="text/css" href="bg.css">
</head>
<body>
    <h1>Heading</h1>

    <h4>Sub heading</h4>

    <p>Main text here</p>
</body>
</html>

body{
    background: url(https://i.imgur.com/SPZdXnP.png);
    background-repeat: no-repeat;
    background-size: cover;
}

h1{
    color: #119DA4;
}

h4{
    color: #80DED9;
}

p{
    color: #AEECEF;
}

background-size: cover;

Click here for Background Size Options Examples Here

Chrome: Inspect

Right Click anywhere on Webpage->Inspect

Open up previous example in chrome and right click, then click Inspect

Borders In CSS

Borders

Color:

Width:

Style:

border-color: blue;

border-width: 5px;

border-style: solid;

Combined:

border: 5px solid blue;

cssBasicBorder

Borders Width

border-width: 1px 4px 12px 4px;

Top Right Bottom Left

Borders Style

border-style: solid;

border-style: dotted;

border-style: double;

border-style: double solid none solid;

Top Right Bottom Left

Borders

CSS Selectors

selector{
    property: value;
    anotherproperty: value;
}

Element Selector
ID Selector
Class Selector

Element Selector

Select ALL instances of a given element

<div>
    <p>Section 1 main text goes here</p>
    <p>Section 1 conclusion text goes here</p>
</div>
<div>
    <p>Section 2 main text goes here</p>
    <p>Section 2 conclusion text goes here</p>
</div>

div{
	background: green;
}

p{
	color: orange;
}

ID Selector

Select an instance with a given ID.

<h1 id="my_id">Heading Text</h1>

#my_id 
{
    color: red;
}

Define ID: use HTML element attribute id

Select id: in CSS use # followed by id name

#

ID Selector

Select an instance with a given ID.

<div>
    <p>Section 1 main text goes here</p>
    <p>Section 1 conclusion text goes here</p>
</div>
<div>
    <p id="importantPar">Section 2 main text goes here</p>
    <p>Section 2 conclusion text goes here</p>
</div>

div{
	background: green;
}

#importantPar {
	color: orange;
}

Each ID can only appear once per HTML page

basicIDSelector

CSS Selectors

selector{
    property: value;
    anotherproperty: value;
}

Element Selector
ID Selector
Class Selector

Class Selector

Select an instance with a given class.

<h1 class="my_class">Heading Text</h1>

.my_class 
{
    color: red;
}

Select Class: in CSS using . followed by class name

Define Class: use HTML element attribute class

Class Selector

Select all elements with a given class

<div>
    <p class="maintext">Section 1 main text goes here</p>
    <p>Section 1 conclusion text goes here</p>
</div>
<div>
    <p class="maintext">Section 2 main text goes here</p>
    <p>Section 2 conclusion text goes here</p>
</div>

div{
	background: green;
}

.maintext {
        background: pink
}

Same class can be assigned to multiple elements on same HTML page

cssClassSelector

CSS Selectors

selector{
    property: value;
    anotherproperty: value;
}

Element Selector
ID Selector
Class Selector

CSS Selectors: Part II

Additional Selectors

*
Descendant
Adjacent
Attribute
n'th of type

Sample Site Overview

<h1>Ulster University</h1>

<a href="https://www.ulster.ac.uk/">Go to Ulster University Website</a>

<div>
    <h4>Schools</h4>
    <ul>
        <li>Computing</li>
        <li>Nursing</li>
        <li>Business</li>
    </ul>
</div>


<div>
    <h3>Computing Courses</h3>
    <ul>
        <li>Information Technology</li>
        <li>Computer Science</li>
        <li>Computer Engineering</li>
    </ul>
</div>


<div>
  <h3>Important Sites</h3>
  <ul>
    <li><a href="https://www.ulster.ac.uk/">Ulster University Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/computing-engineering-and-the-built-environment/schools/computing-engineering-intelligent-systems">Computer Science Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/ulster-university-business-school">Business Home</a></li>
  </ul>
</div>

* Selector

Selects EVERYTHING on the page

<h1>Ulster University</h1>

<a href="https://www.ulster.ac.uk/">Go to Ulster University Website</a>

<div>
    <h4>Schools</h4>
    <ul>
        <li>Computing</li>
        <li>Nursing</li>
        <li>Business</li>
    </ul>
</div>


<div>
    <h3>Computing Courses</h3>
    <ul>
        <li>Information Technology</li>
        <li>Computer Science</li>
        <li>Computer Engineering</li>
    </ul>
</div>


<div>
  <h3>Important Sites</h3>
  <ul>
    <li><a href="https://www.ulster.ac.uk/">Ulster University Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/computing-engineering-and-the-built-environment/schools/computing-engineering-intelligent-systems">Computer Science Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/ulster-university-business-school">Business Home</a></li>
  </ul>
</div>

*
{
    border: 1px solid pink;
}

Descendent Selector

Uses two or more selectors and chains them together

<h1>Ulster University</h1>

<a href="https://www.ulster.ac.uk/">Go to Ulster University Website</a>

<div>
    <h4>Schools</h4>
    <ul>
        <li>Computing</li>
        <li>Nursing</li>
        <li>Business</li>
    </ul>
</div>


<div>
    <h3>Computing Courses</h3>
    <ul>
        <li>Information Technology</li>
        <li>Computer Science</li>
        <li>Computer Engineering</li>
    </ul>
</div>


<div>
  <h3>Important Sites</h3>
  <ul>
    <li><a href="https://www.ulster.ac.uk/">Ulster University Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/computing-engineering-and-the-built-environment/schools/computing-engineering-intelligent-systems">Computer Science Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/ulster-university-business-school">Business Home</a></li>
  </ul>
</div>

li a
{
  color: red;
}

Example: Select all of the <a> tags that are in a <li>

Descendent Selector

Uses two or more selectors and chains them together

ul li a
{
    color: red;
    background-color: yellow;
}

Select all of the <a> tags that are in a <li> that are in a <ul>

More Examples:

<ul>
    <li><a href="https://www.google.com/">Google</a></li>
    <li><a href="http://www.ulster.ac.uk">Ulster</a></li>
    <li>Plain Text</li>
</ul>
		
<ol>
    <li><a href="https://facebook.com">Facebook</a></li>
    <li><a href="https://twitter.com">Twitter</a></li>
</ol>

Descendent Selector

Uses two or more selectors and chains them together

li.myclass
{
  background-color: pink;
}

Select all of the element with a class="myclass"that are in a <li>

More Examples:

<h4 class="myclass">Heading</h4>
<ul>
    <li><a href="https://www.google.com/">Google</a></li>
    <li class="myclass"><a href="http://www.ulster.ac.uk">Ulster</a></li>
    <li class="myclass">Plain Text</li>
</ul>

<ol>
    <li><a href="https://facebook.com">Facebook</a></li>
    <li class="myclass"><a href="https://twitter.com">Twitter</a></li>
</ol>

descendentCSS

Adjacent Selector

Lets us select elements that come after another element

<h1>Ulster University</h1>

<a href="https://www.ulster.ac.uk/">Go to Ulster University Website</a>

<div>
    <h4>Schools</h4>
    <ul>
        <li>Computing</li>
        <li>Nursing</li>
        <li>Business</li>
    </ul>
</div>


<div>
    <h3>Computing Courses</h3>
    <ul>
        <li>Information Technology</li>
        <li>Computer Science</li>
        <li>Computer Engineering</li>
    </ul>
</div>


<div>
  <h3>Important Sites</h3>
  <ul>
    <li><a href="https://www.ulster.ac.uk/">Ulster University Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/computing-engineering-and-the-built-environment/schools/computing-engineering-intelligent-systems">Computer Science Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/ulster-university-business-school">Business Home</a></li>
  </ul>
</div>

h3 + ul
{
  border: 1px solid blue;
}

Example: Select all of the <ul> tags that come directly after a <h4>

adjacentCSS

Attribute Selector

Lets us select elements based of any attribute

<h1>Ulster University</h1>

<a href="https://www.ulster.ac.uk/">Go to Ulster University Website</a>

<div>
    <h4>Schools</h4>
    <ul>
        <li>Computing</li>
        <li>Nursing</li>
        <li>Business</li>
    </ul>
</div>


<div>
    <h3>Computing Courses</h3>
    <ul>
        <li>Information Technology</li>
        <li>Computer Science</li>
        <li>Computer Engineering</li>
    </ul>
</div>


<div>
  <h3>Important Sites</h3>
  <ul>
    <li><a href="https://www.ulster.ac.uk/">Ulster University Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/computing-engineering-and-the-built-environment/schools/computing-engineering-intelligent-systems">Computer Science Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/ulster-university-business-school">Business Home</a></li>
  </ul>
</div>

a[href="https://www.ulster.ac.uk/"]
{
    background: gold;
    color: white;
}

Example: Select <a> tags with a specific href attribute. Make all links to Ulster University Home white on gold background

Attribute Selector

Lets us select elements based of any attribute

input[type="text"]
{
    background: grey;
}

Make all textboxs have a grey background

input[type="email"]
{
    color: blue;
}

Make all text in email inputs have blue text

attributeSelector

n'th of type Selector

Takes a number n and selects the n'th occurrence of a specific element

<h1>Ulster University</h1>

<a href="https://www.ulster.ac.uk/">Go to Ulster University Website</a>

<div>
    <h4>Schools</h4>
    <ul>
        <li>Computing</li>
        <li>Nursing</li>
        <li>Business</li>
    </ul>
</div>


<div>
    <h3>Computing Courses</h3>
    <ul>
        <li>Information Technology</li>
        <li>Computer Science</li>
        <li>Computer Engineering</li>
    </ul>
</div>


<div>
  <h3>Important Sites</h3>
  <ul>
    <li><a href="https://www.ulster.ac.uk/">Ulster University Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/computing-engineering-and-the-built-environment/schools/computing-engineering-intelligent-systems">Computer Science Home</a></li>
    <li><a href="https://www.ulster.ac.uk/faculties/ulster-university-business-school">Business Home</a></li>
  </ul>
</div>

li:nth-of-type(3)
{
    background: purple;
}

Example: Select the 3'rd <il> tag and give it a purple background

advancedSelectors

Inheritance in CSS

Child Elements Inherit Styles from Parent

<div>
    <h1>Test Heading</h1>
    <ul>
        <li>Item 1</li>
        <li>Item 2</li>
    <ul>
</div>

ul
{
    color: red;
}

<ul>

Inheritance in CSS

Child Elements Inherit Styles from Parent

<div>
    <h1>Test Heading</h1>
    <ul>
        <li>Item 1</li>
        <li>Item 2</li>
    <ul>
</div>

div
{
    color: red;
}

<div>

Specificty in CSS

Which styles get applied to an element

<div>
    <h1>Test Heading</h1>
    <ul>
        <li>Item 1</li>
        <li>Item 2</li>
    <ul>
</div>

div
{
    color: red;
}

ul
{
    color: blue;
}

Specificty in CSS

Which styles get applied to an element

<div>
    <h1>Test Heading</h1>
    <ul>
        <li class="important">Item 1</li>
        <li>Item 2</li>
        <li>Item 3</li>
        <li class="important">Item 4</li>
    <ul>
</div>

div
{
    color: red;
}

ul
{
    color: blue;
}

.important
{
    color: green;
}

Specificty in CSS

Which styles get applied to an element

<div>
    <h1>Test Heading</h1>
    <ul>
        <li id="highlight" class="important">Item 1</li>
        <li>Item 2</li>
        <li>Item 3</li>
        <li class="important">Item 4</li>
    <ul>
</div>

div
{
    color: red;
}

ul
{
    color: blue;
}

.important
{
    color: green;
}

#highlight
{
    color: yellow
}

Specificty in CSS

Which styles get applied to an element

<

.myclass1{
    color: orange;
}

input[type="text"]{
    color: orange;
}

div{
    color:red
}

div ul{
    color:red
}

div ul li{
    color:red
}

#myID1{
    color: orange;
}

#myimportantID{
    color: orange;
}

#myheaderID{
    color: orange;
}

Type Selectors

Class & Attribute

Selectors

ID Selectors

More Specific

inheritenceExample

Linking HTML and CSS

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

Inline:

used to apply a unique style to a single HTML element

Linking HTML and CSS

<!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>

Internal:

used to define a style for a single HTML page

Linking HTML and CSS

<!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>

External:

external style sheet is used to define the style for many HTML pages

body 
{
    background-color: powderblue;
}
h1 
{
    color: blue;
}
p 
{
    color: red;
}

styles.css

selectorPractice

Hint 1: Color Codes

Hint 2: You will need to use rgba() at some point to match above exactly

<!DOCTYPE html>
<html>
<head>
	<title>Rainbow Colors</title>
	<link rel="stylesheet" type="text/css" href="rainbowstyle.css">
</head>
<body>
	<h1>Colors of the Rainbow</h1>
	<h3 id="violet">Violet</h3>
	<h3 id="indigo">Indigo</h3>
	<h3 id="blue">Blue</h3>
	<h3 id="green">Green</h3>
	<h3 id="yellow">Yellow</h3>
	<h3 id="orange">Orange</h3>
	<h3 id="red">Red</h3>
</body>
</html>

Edit a style.css to produce the following result:

Rainbow

CSS Intro

By D.Kelly

CSS Intro

3 years ago
1,805

CSS

with CSS

"nouns" and "adjectives"

no CSS

only "nouns"

with CSS

"nouns" and "adjectives"

no CSS

only "nouns"

Zen Garden 1

Zen Garden 2

Zen Garden 3

HTML Box

HTML Box

CSS General Structure

CSS General Structure

CSS General Structure

CSS General Structure

CSS Simple Examples

<link>: Joining HTML and CSS

CSS General Structure

Colour

Color in CSS

Built in Colors

Built in Colors specified by word

Approx 200 built in Colors

Text Color

Color in CSS

Hexadecimal Colors

# + String of 6 hexademical numbers

Approx 6,777,216 colors

Hexadecimal Colors

Color in CSS

RGB Colors

3 Channels: 0-255

Red

Green

Blue

Approx 6,777,216 colors

Color in CSS

RGBA Colors

4 Channels:

Background

Color Contrast

Foreground and Background should be chosen to ensure there is enough contrast for the text to be legible

Color Pallets

Use Colors that Complement Each Other

Color Pallets

Use Colors that Complement Each Other

Pallet Generator

Background Image

Background Image

Exercise:

In Visual Studio Code, create a simple html page with a h1, h4 and p tags (enter some dummy text)

Create a css file and set the following text colors:

Link the html file to the css file

Test in the browser

Set the background image to the following:

Exercise:

Exercise:

Exercise:

Chrome: Inspect

Borders In CSS

Borders

Color:

Width:

Style:

Combined:

Borders Width

Borders Style

CSS Selectors

CSS Selectors

Element Selector

Select ALL instances of a given element

ID Selector

Select an instance with a given ID.

Define ID: use HTML element attribute id

Select id: in CSS use # followed by id name

#

ID Selector