how to change font size and font family in twentytwelve-child

Hello Venkatesh,
There is a lot of repettation in your CSS coding. Instead, define like this.

/* =Theme customization starts here
-------------------------------------------------------------- */
body {
	font-size: 1.5rem;
	font-family: 'PT Serif';
	line-height: 1.6;
}
h1, h2, h3, h4, h5, h6 {
	font-family: 'Fjalla One', sans-serif;
	font-weight: bold;
}
h1 {
	font-size: 3rem;
}
h2 {
	font-size: 2.6rem;
}
h3 {
	font-size: 2.4rem;
}
h4 {
	font-size: 2.2rem;
}
h5 {
	font-size: 2rem;
}
h6 {
	font-size: 1.8rem;
}

Using this technique, you will make more proper change to your presentation than changing values everywhere.

You can’t just declare any font like “Fjalla one”, look at font face: https://css-tricks.com/snippets/css/using-font-face/

Hallow rajat

your solution couldn’t help me.

Hallow andrew

i can’t understand what you are saying.

please help me.

Then it seems like this may a bit out of your depth. Have you considered using a plugin instead?
https://www.ads-software.com/plugins/search.php?q=fonts

Hello Venkatesh,
I did nothing just house keeping to make is more readable. You are repeat your multiple times, which is not a good practice at all.

You want to change your heading to Fjalla One, and text to PT Serif. But, you have not added any source for it. I found these fonts at google.com/fonts, and created an import rule for it.
Add this line of text right after twentytwelve import rule

@import url("https://fonts.googleapis.com/css?family=Fjalla+One|PT+Serif");

Find entire code on my support at github

rajat sir

i added exactly what you posted on GITHUB.font-family has changed, but some text(body) and some h2,h3 so on…has not changed.

please look at site once again

https://myfreelancelifestyle.com

Hello Venkatesh,
Edit to your posts which is not display as it should, and preview in text. You’ll find inline <span> style declaration for paragraph.

Your parent theme is over-riding your child theme style declarations.

Hello rajat, andrew

you solved my problem. may god bless you. thak you both very much.