Phases 1-3 complete and user-verified. Layout shell fully rebuilt from scratch using v7 HTML. Sidebar always dark (data-menu-color=dark). Theme switcher uses v7 __UBOLD_CONFIG__. Dark mode seamless across topbar, sidebar, chat panel, user dropdown. main.template.php fixed: foot.php moved to end (no content after </body>), announcement_alert.php reordered. toolbar.php error_reporting(0) fixed to E_ALL. head.php viewport meta comma fix. Zero PHP errors across dashboard, admin, websites, and users pages. All old files backed up as filename-bk.ext.