CSS core consepts.txt

Em vs rem vs %;
Em is relative to the font size of its direct or nearest parent:
particular div me font-size:20px; set kro aur bad me usko 1em use kro like 1em:20px 
 
Rem is root unit the ability to scale type across the entire page quickly;
agar particular div me font size define nhi hai toh yeh rem ki manega;
like:html{font-size:20px} and inside div like 1rem:20px;
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@import rule
This is used to add css files into direct main css file;
@import "color.css";
@import "printstyle.css" print;
@import "media-768.css" screen and(max-width:768px);
@import url( font awesome link);
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div::before and ::after pesudo element Advanced uses;
*,*::before,*::after{
box-sizing:border-box;}
 
Pesudo element can be used for these purposes:-
p::before{
  content"open quote"
}
p::before{
  content"close quote"
}
1=we can close quotes and open quotes
2=add images top on bottom
3=toollip 
4=font awesome icons like .pdf ,,http,, to make anchor tag more attrective;
5=add counters
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Calc() function stands for -,+,*,/;

height:calc(400px - 20px - 20px - 5px - 5px);  /*remove box-sizing border-box*/
width:calc(400px - 20px - 20px - 5px - 5px);  
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height:400px;
width:400px;
top:calc(50% - 200px);
left:calc(50% - 200px); /*center div in any element*/
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header{                       
width:100%;
height:100px;}

content{            /*fixed responsive layout*/
width:100%;
height:calc(100vh - 100px - 100px);
}

footer{
width:100%;
height:100px;}
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@font-face{
font-family:myname;
src: url(opensans.woff);
src:url(opensans.eot);
}
h1{
font-family:opensans;
WEBSITE=fontsquirrel.com
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POSITIONS
relative=ye jaha par hota hai relative waha se top left leta hai
absolute=ye apne parent k according top left leta hai
fixed=ye bhi apne parent screen ke according kam krta hai
sticky=same as but ye left top screen se value leker sticky hota rehta hai 
static=
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