_CSSNotes.txt

Cascading
-----------------------------------------------------------------------------------------------
Inline CSS has the most priority in terms of getting activated over internal and external ones.
Also, the property that comes last overrides all of the same properties that came before it.
For example, 
	body {
		color: green; 
	     }
if this property comes on internal and then comes to the inline, the inline will get the effect.
Inline > Internal > External


CSS Vocabulary
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h1 {
    font-size: 128px;
}

h1 {
    font-size: small;
}

h1 {
    font-size: 100%; --> means, same as default font hight
    font-size: 200%; --> means, twice as default font hight		
}


Selects all children and grand-children:
section b {
    color: blueviolet;
}


Selects all DIRECT children:
section > b {
    color: blueviolet;
}
section > b, div > b {
    color: blueviolet;
}

Class and ID
-----------------------------------------------------------------------------------------------
class can be applied to MULTIPLE elements and a SINGLE element can have MULTIPLE classes
An ID CANNOT be used on MULTIPLE elements and an element CANNOT have MULTIPLE IDs

Specificity
-----------------------------------------------------------------------------------------------

1. If there are multiple rules in a same specificity, the last rule will override

body {
    background-color: aqua;
}
body {
    background-color: goldenrod;
}

Here, goldenrod will override aqua


2. More specific rule will override

html body {
    background-color: aqua;
}
body {
    background-color: goldenrod;
}

Here, aqua will override goldenrod

3. Class will over rule below:

.class {
    background-color: red;
}
html body {
    background-color: aqua;
}
body {
    background-color: goldenrod;
}

Here, red will override all.


4. class with more specificity will overrule below:
html .class {
    background-color: tomato;
}
.class {
    background-color: goldenrod;
}
html body {
    background-color: aqua;
}
body {
    background-color: goldenrod;
}

Here, tomato will override all.

5. ID will overrule all below:
#id {
    background-color: blueviolet;
}
html .class {
    background-color: tomato;
}
.class {
    background-color: goldenrod;
}
html body {
    background-color: aqua;
}
body {
    background-color: goldenrod;
}

Here, blueviolet will override all.

6. Inline will OVERRULE everyone!

More about specificity: https://developer.mozilla.org/en-US/docs/Web/CSS/Specificity
Specificity Calculator: http://specificity.keegan.st/


Setting Widths and Heights in CSS
-----------------------------------------------------------------------------------------------
Inline Elements:
width and height cannot be applied
width of inline is dependent on its contents

To add height and width to an inline element, do this:
#inline * {
    display: inline-block;
    width: 200px;
    height: 100px;
}

em: based on default font-size inherited by this element

Block-level Elements:
Always starts with a new line
Takes the full width of its parent elemen that is available by default

More about inline and block-level elements: https://www.w3schools.com/html/html_blocks.asp


Length units in CSS
-----------------------------------------------------------------------------------------------
==> em

browser default fontsize = 16px
.bar {
    width: 20em; ==> 20 * 16 = 320px
}
.progress {
    width: 10em; ==> 10 * 16 = 160px
}

.bar {
    font-size: 8px; // here, we override browser default font size
    width: 20em;    // So, here we have 20 * 8 = 160px!
}
.progress {
    font-size: 16px;
    width: 10em;
}

==> rem : Need to learn about it

Colors in CSS
-----------------------------------------------------------------------------------------------
==> No need to do anything with it

CSS Padding
-----------------------------------------------------------------------------------------------
padding: 10px // top-down left-right each will have 10px padding
padding: 10px 20px // top-down = 10px;  left-right = 20px of padding
padding: 1px 2px 3px 4px // clock-wise move top > right > bottom > left

when we add padding, the original width and height increases. To keep it to its original size,
we have to add:
box-sizing: border-box;
**NEED EXPERIMENT WITH box-sizing

CSS Borders
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==> No need to do anything with it

CSS Margins
-----------------------------------------------------------------------------------------------
==> No need to do anything with it

CSS Box Model
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==> No need to do anything with it

CSS Visibility
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display: none; ==> the element will be removed from DOM
visibility: hidden; ==> it will be there in DOM but in an invisible state
opacity: 0; ==> it will be there in DOM but in an invisible state

CSS Fonts
-----------------------------------------------------------------------------------------------
==> No need to do anything with it

CSS Flow
-----------------------------------------------------------------------------------------------
Inline element: will take the amount of space of its contents. They are stacked horizontally. 
If there is no space remain in the window, its contents will go to the next line! 
They don't take width and height properties!
anchor <a>, <span>, <b> <i> all are inline elements..

display: block ==> makes an inline element behave like a block element
display: inline-block ==> to add heigh and width to an inline element

Block elements: are stacked vertically by default. Take 100% width of their parent elements! They will be stacked in 
the order they are found in the HTML. They can take width and height. They will always stack vertically even if
theoretically they have space to go side by side. 
<div> <h1 - h6> <p> all are block elements.

display: inline ==> makes a block element behave like an inline element