Annoj

What do you mean?

I reinstalled the original stylesheet. But I am not able to make the changes in the website to make the site look good on a mobile

Thank you for your reply.
I would like to use the child stylesheet, but I don’t know how to copy the code to the childtheme.

You mean the text on the right hand side?

I use the theme twenty eleven

I dont have a gallery.
Which plugin do you recommend to make the website compatible for mobile devices?

Sorry, what do you mean?

Thank you for you reply.
I do not understand how I can make sure my website is free of errors.
Do I first have to uninstall WPTouch?
And where can I find the error panel? And what is a user agent switcher?

Now it works. But the blue bar also dissapeared. I would like this to stay

Yes, I created the child them.
And I also changed the header.php (before I created the child theme)

It is the first time I made a website. What is the best I can do now?

Ps the code you recommended does not work

Exactly. I would like to remove the widgets at the bottom.

What does it mean: mark-up errors?

Yes, I did.
But somehow I can’t hide it

Only the section with the text content I would like to have a blue border.

To be quite honest: I see no difference…

After all I think it’s better to make the vertical lines shorter (stop at the top at the menu bar and at the bottom at the height of the big horizontal bottom)

Do you mean I have to delete this?
textarea {
background: #fafafa;
-moz-box-shadow: inset 0 1px 1px rgba(0,0,0,0.1);
-webkit-box-shadow: inset 0 1px 1px rgba(0,0,0,0.1);
box-shadow: inset 0 1px 1px rgba(0,0,0,0.1);
border: 1px solid #ddd;
color: #888;
}