Insert HTML-CSS-Javascript Codes in Blogger Posts As Plain Text

Insert CSS Style Sheet in Blogger Template:
First we will insert the CSS style Sheet to stylize our quote box.
Go to Blogger >> Your Blog >> Template >> EDIT HTML >> Proceed
And now Search For ]]>

With (CTRL+F)
After you find ]]> just above it paste the following coding

.post blockquote {
background: #C8EFFF url(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhD6AhMC0uKgN3CWIJgh7q-wdP6EAijWWbuUSQhXKctNHCjPDgKLKCs1CuROZ3TMheROpnNwNlquWRDCB7OXIbeOH2LcFurCkYULh4ljzJvg48zYWDwJRSQwlIz3Q_B5G1eXM-qsFnFRB0/s1600/1.png);
background-position:top left;
background-repeat:repeat-y;
margin: 0 20px;
padding: 10px 20px 10px 45px;
border-top: 2px solid #DDD;
border-right: 5px solid #666;
border-left: 2px solid #DDD;
border-bottom: 5px solid #666;
font-size: 0.9em;
}
.post blockquote p {
margin: 0;
padding: 0 0 15px;
}
.blockquote {
font: 18px normal  sans-serif,Tahoma;
padding-top: 10px;
margin: 5px;
text-indent: 65px;
}
.blockquote div {
display: block;
padding-bottom:10px;
}
.blockquote p {
margin: 0;
padding-top:10px;
}

Now After pasting the above code save your template by pressing Save Template Button

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