child theme looking different

This is what I see in your child’s theme style.css:

/*
 Theme Name:   Twenty twelve Child
 Theme URI:    https://myfreelancelifestyle.com/twenty-twelve-child/
 Description:  Twenty twelve Child Theme
 Author:       venkatesh khajjidoni
 Author URI:   https://myfreelancelifestyle.com
 Template:     twentytwelve
 Version:      1.0.0
 Tags:         light, dark, two-columns, right-sidebar, responsive-layout, accessibility-ready
 Text Domain:  twenty-twelve-child
*/

/*
For older themes, and themes that do not use wp_enqueue_style() to enqueue their stylesheet, use the following line where twentytwelve is the name of the directory where the theme resides:

@import url("../twentytwelve/style.css");
*/

/* =Theme customization starts here
-------------------------------------------------------------- */

#site-navigation {
margin: 0px;
}
#masthead {padding-top: 10px}

The @import part is inside /* */, which is CSS comment. If you wish to use @import url, you need to bring it out of the comment. See the code below, notice @import area.

/*
 Theme Name:   Twenty twelve Child
 Theme URI:    https://myfreelancelifestyle.com/twenty-twelve-child/
 Description:  Twenty twelve Child Theme
 Author:       venkatesh khajjidoni
 Author URI:   https://myfreelancelifestyle.com
 Template:     twentytwelve
 Version:      1.0.0
 Tags:         light, dark, two-columns, right-sidebar, responsive-layout, accessibility-ready
 Text Domain:  twenty-twelve-child
*/

@import url("../twentytwelve/style.css");

/* =Theme customization starts here
-------------------------------------------------------------- */

#site-navigation {
margin: 0px;
}
#masthead {padding-top: 10px}

Also please note that using enqueue is generally preferred over @import style nowadays.

thank you. it helped