Created /Documentation/UI_Design_Guide/ with 6 documents: README.md (index with gold standard file references), Quick_Start.md (5-min page setup with framework versions, minimal template, directory structure, sidebar registration), Components.md (14 copy-paste UI components — header bar, stat cards, tabs, card-box, forms, buttons, tables, labels, alerts, progress bars, modals, spinners, empty states, list rows), CSS_Classes.md (colors, spacing, typography, layout, grid, responsive, Bootstrap 3 vs 4/5 gotchas), JavaScript_Patterns.md (AJAX helper, response format, SweetAlert, lazy tabs, button states, form submission, DataTables, utilities, CSRF, controller pattern), Page_Templates.md (3 full templates — tenant settings tabbed page, admin dashboard, CRUD with modal), Checklist.md (pre-launch checklist covering structure, forms, tables, AJAX, loading, tabs, security, responsive, styling, DO NOTs).