CSS BASICS PART II

CSS List Properties

Property                 Description

list-style                 Sets all the properties for a list in one declaration

list-style-image Specifies an image as the list-item marker

list-style-position Specifies the position of the list-item markers (bullet points)

list-style-type         Specifies the type of list-item marker

The list-style property is a shorthand property. It is used to set all the list properties in one declaration
Example:

ul {
  list-style: square inside url("sqpurple.gif");
}

When using the shorthand property, the order of the property values are:

list-style-type

list-style-position 

list-style-image

The display Property

The display property specifies if/how an element is displayed.

Every HTML element has a default display value depending on what type of element it is. The default display value for most elements is block or inline.

Block-level Elements

A block-level element always starts on a new line and takes up the full width available (stretches out to the left and right as far as it can).

Examples of block-level elements:

<div>

<h1> - <h6>

<p>

<form>

<header>

<footer>

<section>

Inline Elements

An inline element does not start on a new line and only takes up as much width as necessary.

Examples of inline elements:

<span>

<a>

<img>

Display: none

display: none; is commonly used with JavaScript to hide and show elements without deleting and recreating them. 

The <script> element uses display: none; as default. 

Hiding an element can be done by setting the display property to none. The element will be hidden, and the page will be displayed as if the element is not there:

Example:

h1.hidden {

  display: none;

}

visibility:hidden; also hides an element.

However, the element will still take up the same space as before. The element will be hidden, but still affect the layout:

The position Property

The position property specifies the type of positioning method used for an element.

There are five different position values:

static

relative

fixed

absolute

sticky

Elements are then positioned using the top, bottom, left, and right properties. However, these properties will not work unless the position property is set first. They also work differently depending on the position value.

position: static

HTML elements are positioned static by default.

Static positioned elements are not affected by the top, bottom, left, and right properties.

An element with position: static; is not positioned in any special way; it is always positioned according to the normal flow of the page.

position: relative

An element with position: relative; is positioned relative to its normal position.

Setting the top, right, bottom, and left properties of a relatively-positioned element will cause it to be adjusted away from its normal position. Other content will not be adjusted to fit into any gap left by the element.

position: fixed

An element with position: fixed; is positioned relative to the viewport, which means 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.

A fixed element does not leave a gap in the page where it would normally have been located.

position: absolute

An element with position: absolute; is positioned relative to the nearest positioned ancestor (instead of positioned relative to the viewport, like fixed).

However; if an absolute positioned element has no positioned ancestors, it uses the document body, and moves along with page scrolling.

Note: A "positioned" element is one whose position is anything except static.

position: sticky

An element with position: sticky; is positioned based on the user's scroll position.

A sticky 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 - then it "sticks" in place (like position:fixed).

Overlapping Elements

• When elements are positioned, they can overlap other elements.
• The z-index property specifies the stack order of an element (which element should be placed in front of, or behind, the others).
• An element can have a positive or negative stack order
• An element with greater stack order is always in front of an element with a lower stack order.

Note: If two positioned elements overlap without a z-index specified, the element positioned last in the HTML code will be shown on top.

CSS Overflow

The overflow property specifies whether to clip the content or to add scrollbars when the content of an element is too big to fit in the specified area.

The overflow property has the following values:

visible - Default. The overflow is not clipped. The content renders outside the element's box

hidden - The overflow is clipped, and the rest of the content will be invisible

scroll - The overflow is clipped, and a scrollbar is added to see the rest of the content

auto - Similar to scroll, but it adds scrollbars only when necessary

 Note: The overflow property only works for block elements with a specified height.

• The overflow-x and overflow-y properties specifies whether to change the overflow of content just horizontally or vertically (or both)
• overflow-x specifies what to do with the left/right edges of the content.
• overflow-y specifies what to do with the top/bottom edges of the content.

The float Property

The float property is used for positioning and formatting content e.g. let an image float left to the text in a container.

The float property can have one of the following values:

left - The element floats to the left of its container

right - The element floats to the right of its container

none - The element does not float (will be displayed just where it occurs in the text). its default

inherit - The element inherits the float value of its parent

In its simplest use, the float property can be used to wrap text around images.

The clear Property

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

The clear property can have one of the following values:

none - Allows floating elements on both sides. This is default

left - No floating elements allowed on the left side

right- No floating elements allowed on the right side

both - No floating elements allowed on either the left or the right side

inherit - The element inherits the clear value of its parent

The most common way to use the clear property is after you have used a float property on an element.

When clearing floats, you should match the clear to the float: If an element is floated to the left, then you should clear to the left. Your floated element will continue to float, but the cleared element will appear below it on the web page.

The display: inline-block Value

Compared to display: inline, the major difference is that display: inline-block allows to set a width and height on the element.

Also, with display: inline-block, the top and bottom margins/paddings are respected, but with display: inline they are not.

Compared to display: block, the major difference is that display: inline-block does not add a line-break after the element, so the element can sit next to other elements.

Center Align Elements

To horizontally center a block element (like <div>), use margin: auto;

Setting the width of the element will prevent it from stretching out to the edges of its container.

CSS Combinators

A combinator is something that explains the relationship between the selectors.

A CSS selector can contain more than one simple selector. Between the simple selectors, we can include a combinator.

There are four different combinators in CSS:

descendant selector (space)

child selector (>)

adjacent sibling selector (+)

general sibling selector (~)

Selector                     Example Description

element element     div p         Selects all <p> elements inside <div> elements

element>element     div > p         Selects all <p> elements where the parent is a <div> element

element+element     div + p         Selects the first <p> element that are placed immediately after                                                             <div> elements

element1~element2    p ~ ul         Selects every <ul> element that are preceded by a <p> element

Pseudo-classes

A pseudo-class is used to define a special state of an element.

For example, it can be used to:

• Style an element when a user mouses over it
• Style visited and unvisited links differently
• Style an element when it gets focus

REFER Here:

https://www.w3schools.com/css/css_pseudo_classes.asp

https://www.w3schools.com/css/css_pseudo_elements.asp