Menu on responsive twentytwelve theme not working, strange url error

There are a few code edits you might have to do.. So lets go step by step..

1. Change in the places you use, <?php echo esc_url( home_url( "https://wordpress.stackexchange.com/" ) ); ?> to get the home page url, you can replace it with <?php get_site_url(); ?> which will get you your site URL.
2. Next you are using the code of Site Title,
   <h1 class="site-title"><a href="https://wordpress.stackexchange.com/questions/179359/<?php echo esc_url( home_url("https://wordpress.stackexchange.com/" ) ); ?> </a></h1>
<h2 class="site-description"><?php bloginfo( 'description' ); ?></h2>
   coz if you arent you can comment this code with <!-- <code> --> tags. IF you are, then you could add the necessary text or use it as,
3. What is this line of code used for? <a class="assistive-text" href="#content" title="<?php esc_attr_e( 'Skip to content', 'twentytwelve' ); ?>"><?php _e( 'Skip to content', 'twentytwelve' ); ?></a> coz its creating some html tag errors, you could comment this out too.

So once you are done with these changes let me know if it worked as you wanted or do you still face any issues.