Great, it works. Thanks for the quick help!

Brilliant I am thrilled. Worked and looks perfect. THANKS

Now I still have the problem that in the mobile view the distance between content and sidebar is a bit very big. In addition, I do not like the dashed line, I would like to use a continuous one.

First of all thanks for the first code, it worked.
With the truncated container on the right side I am at a loss. So here is the whole code. Can you find an error here?

.content { padding-bottom: 20px; }
.content { padding-top: 30px; }

#socket .container {
  padding-top: 10px;
  padding-bottom: 10px;
}

#socket .sub_menu_socket div {
    overflow: visible;
}
#socket .menu {
    margin-top: -8px;
}
#top .inner_sidebar {
    margin-left: 20px !important;

}
#footer { padding: 0px 0 0px 0; }

.main_menu .menu ul { width: 130px; }

@media only screen and (max-width: 767px) {
.responsive #scroll-top-link {
    display: block !important;
}}

@media only screen and (max-width:767px) {
  .responsive #top #wrap_all #header {
    position: fixed !important;
  }

  .responsive #top #main {
    padding-top: 81px !important;
  }}

@media only screen and (max-width: 767px) {
    #top #wrap_all #footer .flex_column, #top #wrap_all  #footer .widget {
        margin: 7px;
    }
}

#footer .container {
  display: flex;
  align-items: flex-end;
  flex-flow: row wrap;
  justify-content: space-between;
}

.responsive .container {
  max-width: 1130px;
}

Great, thank you very much! It worked.

Best regards, Chris