Disable the admin toolbar

My best guess is that you applied the style in your theme’s style.css file, which does not get loaded in the dashboard, hence the bar continues to appear.
You will need to create a plugin to help you style the dashboard. More information on how this can be done you can find here and here.

Hi nvourva,
my theme not execute ovverride of default CSS.

I use Firebug and I see that to the div #wp-admin-bar-root-default is applied the style by:
https://www.mysite.com/wp-admin/load-styles.php?c=1&dir=ltr&load=dashicons,farbtastic,admin-bar,wp-admin,buttons,media-views,wp-auth-check&ver=4.0

Perhaps my initial post was not very clear.
Where did you add the

#wp-admin-bar-root-default {
   display: none! important;
}

style in order to hide the left side of the admin bar on the front end?

HI @nvourva,
I used My Custom Css.