Getting started with Basic Styling

In this episode, we will quickly go through basics of CSS.

As mentioned in the Introduction episode, CSS adds styling to the web page.

There are three types of ways of adding CSS to web page:

Inline CSS
Internal CSS
External CSS

CSS Syntax

Inline CSS

Used to apply a unique style for a single element.

<h1 style="color:blue;text-align:center;">
  Section heading
</h1>

<p style="color:red;">
  Section paragraph.
</p>

Result

Section heading

Section paragraph.

Internal CSS

Include CSS rules for single HTML page and has effect within that page. It is defined in the <head> section using <style> element.

<head>
  <style>
    h1 {
      color: blue;
      text-align: center;
    }
    p { color: red; }
  </style>
</head>

<body>
  <h1> Section heading </h1>
  <p> Section paragraph One. </p>
  <p> Section paragraph Two. </p>
</body>

Result

Section heading

Section paragraph One.

Section paragraph Two.

NOTE: The benefit of Internal CSS here is that we avoid writing separate CSS for 2nd <p> tag.

External CSS

The CSS rules are defined in separate file with extension .css.
Each HTML page must include a reference to the external stylesheet file (.css) using the <link> element, inside the <head> section.
Following line include style.css style sheet file in the web page.
```
<link href="style.css" rel="stylesheet" type="text/css">
```
The content of style.css will contain the CSS rules for the elements.

Example:

h1 {
  color: blue;
  text-align: center;
}
p {
  color: red;
}

Comment

Comment is used to explain the code which might be useful for self or for others.
These are not displayed or rendered in the web page.
Syntax:
```
/* Write your comments here */
```

CSS Selectors

A CSS selector is used to select the HTML element(s) that we can style.
Common CSS categories:
- Simple selectors (name, id, class)
- Combinator selectors (relation between two selector)
  - Descendant selector (space)
  - Child selector ( > )
  - Normal sibling selector ( ~ )
  - Adjacent sibling selector ( + )
- Pseudo-class selectors (based on certain state)
- Pseudo-elements selectors (select and style a part of an element)
- Attribute selectors (based on an attribute or attribute value)

Simple Selectors

  /* element selector */
  p {
    color: red;
  }

  /* ID selector */
  #para {
   color: red;
  }

  /* class selector */
  .red {
    color: red;
  }

  /* specific class selector */
  /* select all <p> elements with class 'red'. */
  p.red {
    color: red;
  }

multiple selectors

We can specify more than one selectors to select group of elements.
```
#para .red {
  color: red;
}

#about h1 .center {
  text-align: center;
}
```
NOTE: We can have any type of selector (id, class or element) in above places.

Universal Selector

Selects all HTML elements on the page.

* {
  color: blue;  /* Set the color of whole page as blue */
}

/* Widely used Reset CSS */
* {
  /* Include padding and border in the element's total width and height */
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

Exercise: ‘border-box’ case

Create two boxes with same width, height, padding and border.

Set height as 300px and width as 100px.

Padding as 30px.

Set border of Box 1 as 10px solid blue and other as 10px solid red.

Set box-sizing of Box 1 as content-box(default) while other as border-box.
Solution
<head>
  <style>
    .box1 {
      box-sizing: content-box;
      width: 300px;
      height: 100px;
      padding: 30px;
      border: 10px solid blue;
    }
    .box2 {
      box-sizing: border-box;
      width: 300px;
      height: 100px;
      padding: 30px;
      border: 10px solid red;
    }
  </style>
</head>

<body>
  <div class="box1">Box 1</div>
  <div class="box2">Box 2</div>
</body>
NOTE: Hence box-sizing: border-box has become one of important reset CSS.

Colors

Following are popular ways of specifying colors in CSS:

Color names
- These are specific color name like red, aqua, chocolate, gold etc.
- Know more
RGB (Red, Green and Blue)
- Color value is specified with combination of rgb(red, green, blue).
- Each parameter defines the intensity of the color as an integer between 0 and 255.
- Example: rgb(0, 0, 255) is blue, rgb(255, 0, 0) is red etc
- Know more
HEX (Hexadecimal values)
- Color is specified with hexadecimal value in the format: #RRGGBB.
- RR(red), GG(green) and BB(blue) are hexadecimal integers between 00 and FF specifying the intensity of the color.
- Know more

RGBA (RGB with Alpha)

Color value is specified with: rgba(red, green, blue, alpha)
alpha specifies the opacity of the color.
Know more

h1 {
  color: #ff0000;
}
h2 {
  color: rgb(255, 0, 0);
}
h3 {
  color: red;
}

/* above are same way of getting red color */

CSS Units

CSS has several different units for expressing a length.
Following are popular units which are widely used:
- px: Pixels (1px = 1/96th of 1 inch)
- em: Relative to the font-size of the element.
- rem: Relative to font-size of the root element.
- vw: Relative to 1% of the width of the viewport.
- vh: Relative to 1% of the height of the viewport.
- %: Relative to the parent element.
Instructor

Show the demo of different CSS units. Also, explain concepts like Viewport etc.

CSS Background

The background properties are used to add background effects for html elements.
The background property is shorthand for following properties:
- background-color
- background-image
- background-position
- background-size
- background-repeat
- background-attachment

Shorthand syntax:

background: bg-color bg-image position/bg-size bg-repeat bg-origin bg-clip bg-attachment initial|inherit;

div {
  background-color: #333;
  background-image: url("images/background.jpg");
  background-position: center center;
  background-size: cover;
  background-repeat: no-repeat;
  background-attachment: fixed;
}

/* shorthand */
div {
  background: #333 url("images/background.jpg") center center/cover no-repeat fixed;
}

opacity property specifies the transparency of an element. It can take a value from 0.0 to 1.0. Lower the value of opacity, more transparent it is.
Know more

Border

The border property allow you to specify the style, width, and color of an element’s border.
The border property is a shorthand property for the following individual border properties:
- border-width
- border-style (required)
- border-color
```
p {
  border: 5px solid red;
}
```

Left border can be easy created using below:

p {
  border-left: 6px solid blue;
  background-color: #ddffff;
}

Know more

Margin

margin property is used to create space around all sides of element and defined outside of any borders.

p {
  margin-top: 20px;
  margin-bottom: 10px;
  margin-right: 20px;
  margin-left: 10px;
}

/* Short hand notation */
p {
  margin: 20px 10px;
}

/* Same margin on all sides */
p {
  margin: 20px;
}

Special case: Setting margin value to auto will let the browser calculate the margin. See margin: auto.
Negative values are allowed in margin.

Padding

padding property is used to create space around element’s content and defined inside of any borders.

p {
  padding-top: 20px;
  padding-bottom: 10px;
  padding-right: 20px;
  padding-left: 10px;
}

/* Short hand notation */
p {
  padding: 20px 10px;
}

/* Same padding on all sides */
p {
  padding: 20px;
}

NOTE: Negative values are not allowed in padding.

CSS Box Model

Everything in CSS has a box around it.
This concept is key to being able to create layouts with CSS, or to align items with other items.

It consists of: margins, borders, padding, and the actual content.

Box Model

div {
  width: 300px;
  border: 15px solid green;
  padding: 50px;
  margin: 20px;
}

/* Create an empty div in body */

Developer Tools

Instructor

Give the demo of Developer Tools and its usage.

Text formatting through CSS

The color is used to give text color.
The text-align property is used to set the horizontal alignment of a text. It can be center, left, right or justify.
The vertical-align property sets the vertical alignment of an element. The values can be top, middle or bottom.
The text-decoration property is used to set or remove decorations from text.
The text-transform property is used to specify uppercase and lowercase letters in a text. The values are uppercase, lowercase or capitalize.

The line-height property is used to specify the space between lines.

p {
  text-decoration: underline;
  text-indent: 50px;
  letter-spacing: 2px;
  line-height: 30px;
  white-space: nowrap;
}
.upper {
  text-transform: uppercase;
}
.underline {
  text-decoration: underline;
}
.no-underline {
  text-decoration: none;
}

Font

The font adds value to your text and has huge impact on how the users experience the web page.
It is also important to choose the correct color and text size for the font.
Following are common font families:
- Serif fonts have a small stroke at the edges of each letter. (formality and elegance)
- Sans-serif fonts have clean lines (no small strokes attached). (modern and minimalistic look)
- Monospace has all the letters having the same fixed width.
- Cursive fonts imitate human handwriting.
The font-family property to specify the font of a text.

The font-family should hold several font names as a “fallback” system, to ensure maximum compatibility between browsers/operating systems.

  
<p style="font-family: 'Georgia'">
  The Serif Font
</p>
<p style="font-family: 'Verdana'">
  The Sans-Serif Font
</p>
<p style="font-family: 'Lucida Console'">
  The Monospace Font
</p>
<p style="font-family: 'Brush Script MT'">
  The Cursive Font
</p>
  

Exercise: Different Fonts

<p style="font-family: 'Georgia'">
  The Serif Font
</p>
<p style="font-family: 'Verdana'">
  The Sans-Serif Font
</p>
<p style="font-family: 'Lucida Console'">
 The Monospace Font
</p>
<p style="font-family: 'Brush Script MT'">
  The Cursive Font
</p>

Result

The Serif Font

The Sans-Serif Font

The Monospace Font

The Cursive Font

The font-style property is mostly used to specify italic text.
The font-size property sets the size of the text.
The font shorthand property has following:
- font-style
- font-variant
- font-weight
- font-size/line-height
- font-family
```
p {
  font: italic small-caps bold 16px/30px Georgia, serif;
}
```

Styling Link

Links can be styled with any CSS property like color, font, background etc.
There are following four states of links:
- a:link - a normal, unvisited link
- a:visited - a link the user has visited
- a:hover - a link when the user mouses over it
- a:active - a link the moment it is clicked
```
a:link {
  color: blue;
}
a:visited {
  color: brown;
}
a:hover {
  color: red;
}
a:active {
  color: darkblue;
}
```

Google Font

We can use Google hosted fonts which are free to use.
Just add a special style sheet link in the <head> section and then refer to the font in the CSS.

<head>
  <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Poppins">

  <style>
  body {
    font-family: "Poppins", sans-serif;
  }
  </style>
</head>

CSS layout using ‘display’ property

The display property specifies how an element is displayed in the web page.

It is the most important CSS property for controlling layout.

display: block;  /* make the element block */
display: inline;  /* make the element inline */
display: none;  /* hide element */

Exercise: Inline Nav items

Give the code below make the nav items horizontally
<ul>
  <li><a href="#" target="_blank">HTML</a></li>
  <li><a href="#" target="_blank">CSS</a></li>
  <li><a href="#" target="_blank">JavaScript</a></li>
</ul>
NOTE: # in href indicate that it points to nowhere.
Solution Hint

Just add CSS to li element as below:
li {
  display: inline;
}

Inline Block display layout

display: inline-block allows user to set a width and height on the element.

NOTE: We cannot set height and width property in display: inline layout.
Check the example by W3school.

Centering element, text and image

margin: auto is used to center HTML element.
text-align: center is used to center text.

display: block, margin-left/right and width are used to center an image.

img {
  display: block;     /* required since img is inline element */
  margin-left: auto;
  margin-right: auto;
  width: 300px;       /* required if width size is greater than screen width */
}

width and max-width

width property will prevent the block-level element from stretching to whole screen width.

margin: auto is used to horizontally center the element.

Example

Here the first box has width of 600px while second box has max-width of 600px. Check by reducing the screen width.
<div style="width: 600px; margin: auto; background: lightgreen; margin-bottom: 1rem;">
  Fixed Width Box
</div>
<div style="max-width: 600px; margin: auto; background: yellow; margin-bottom: 1rem;">
  Flexible Width Box
</div>

Float and clear property

The float property specifies how an element should float in the web page.
It is used for positioning content.
The values for float can be left, right, none or inherit.

The clear property specifies what elements can float beside the cleared element and on which side.

Example

<style>
  img {
    float: right;
  }
</style>
<p>
  <img src="images/html.png" alt="User" style="width:150px;height:150px;margin-left:15px;">
  This is a nice paragraph with HTML logo image on the right.
</p>

The values for clear can be left, right, none, both, or inherit.
When clearing floats, you should match the clear to the float i.e if an element is floated to the left, then you should clear to the left.
Check the example by w3school.

position property

The position property specifies the type of positioning method used for an element.
There are five different position values:

1. static
- It is always positioned according to the normal flow of the page.
- Static positioned elements are not affected by the top, bottom, left, and right properties.
2. relative
- Element is positioned relative to its normal position.
- The top, right, bottom, and left properties will decided the movement of element.
  
  Example
  
  This is normal text and has default position which is 'static'
  
  This div element is positioned 20px from top side of its normal position.
  
  3. absolute
  - Positioned relative to the nearest positioned ancestor.
  - Uses document body if there is no positioned ancestors.
  NOTE: A “positioned” element is one whose position is anything except static
  
  Example
  
  This div element has position 'relative'.
  This div element has position 'absolute'.
4. fixed
- Positioned relative to the viewport
- It always stays in the same place even if the page is scrolled.
- The top, right, bottom, and left properties are used to position the element.
- Check the example in w3school.
5. sticky
- Positioned based on the user’s scroll position.
- Element toggles between relative and fixed, depending on the scroll position.
- It is positioned relative until a given offset position is met in the viewport and then it “sticks” in place like fixed element.
- Check the example in w3school.

Overlapping Element (z-index)

The z-index property controls the vertical stacking order of elements that overlap.
It controls which element should appears physically closer to you.
It only affects elements that have a position value other than static (the default).
Following image will help you understand the overlapping concept.
The higher the value of z-index, closer it will to your eyes.

It is possible that two elements can overlap each other like in below case:

<style>
img {
  position: absolute;
  left: 0px;
  top: 0px;
  /* CSS here */
}
</style>

<h1>This is a heading</h1>
<img src="images/user.png" width="100" height="140">
<p>
  This is paragraph and the image get overlap to it.
  To fix it, you need to add 'z-index; -1' to 'img' tag.
</p>

Exercises

Exercise: Sample Web Page

Open the CodePen link.

Click on Fork link at the bottom right corner.

Update the CSS panel as per the instructions given.

Output preview

The web page should look like below:-

Exercise: Bootstrap like buttons

Open the CodePen link.

Click on Fork link at the bottom right corner.

Update the CSS panel as per the instructions given.

Output preview

The web page should look like below:

Previous Next

Getting started with Basic Styling

Getting started with Basic Styling

CSS Syntax

Inline CSS

Result

Section heading

Internal CSS

Result

Section heading

External CSS

Comment

CSS Selectors

Simple Selectors

multiple selectors

Universal Selector

Exercise: ‘border-box’ case

Solution

Colors

CSS Units

Instructor

CSS Background

Border

Margin

Padding

CSS Box Model

Developer Tools

Instructor

Text formatting through CSS

Font

Exercise: Different Fonts

Result

Styling Link

CSS layout using ‘display’ property

Exercise: Inline Nav items

Solution Hint

Inline Block display layout

Centering element, text and image

width and max-width

Example

Float and clear property

Example

position property

1. static

2. relative

Example

3. absolute

Example

4. fixed

5. sticky

Overlapping Element (z-index)

Exercises

Exercise: Sample Web Page

Output preview

Exercise: Bootstrap like buttons

Output preview

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