To stop those 3 items from showing in the sidebar use this CSS code.
.nav-sitetools, .nav-usermenu, .nav-trace { display: none; }
You can place this CSS code in an existing CSS file of the sprintdoc theme in the lib/tpl/sprintdoc/css
folder at the top of the file, or create a new CSS file just for your edits and include it by editing style.ini