LEDMatrix/docs/audits/WEB_UI_AUDIT_2026-09.md

Web UI Technical Audit — September 2026

Scope: web_interface/ (Flask + HTMX + Alpine, templates/v3/, static/v3/). Method: Impeccable design detector, code review (accessibility; performance, theming, responsive), and a live pass on the running app at desktop and 375px mobile widths in light and dark themes. Severe claims were verified against the live page; one was rejected (see below). No code was changed.

Product context: see PRODUCT.md.

Health score: 8/20 (Poor)

#	Dimension	Score	Key finding
1	Accessibility	2	Focus rings never render; modals have no dialog semantics or focus management
2	Performance	2	~1.2 MB JS (≈250 KB gzip) on every page; SSE streams and polling never pause
3	Responsive	2	Mobile drawer works; header title wraps to 3 lines; many ~24px touch targets
4	Theming	1	Tokens exist but hex dominates; dark mode is a class-by-class patch with leaks
5	Implementation integrity	1	Templates use Tailwind classes that don't exist in the stylesheet

Implementation integrity verdict: fail

There is no Tailwind build. static/v3/app.css is a hand-written subset of Tailwind, while templates and JS are authored as if full Tailwind were loaded.

• 333 of 516 utility class names used have no CSS rule (2,582 uses), confirmed against the live stylesheets. Top offenders: border (250), text-gray-700 (183), block (148), mr-1 (127), hidden (79), py-1, text-blue-600, px-2, text-center, hover:bg-blue-700, divide-y, uppercase, font-mono.
• .hidden has never existed in app.css, so the 145 classList.add/remove/toggle('hidden') calls across 26 files do nothing. Visible proof: the header shows both the moon and sun theme icons.
• 15 classes are defined only under [data-theme="dark"] (e.g. bg-blue-50, bg-red-50, bg-yellow-50, border-blue-200, text-red-700), so tinted notice boxes are unstyled in light mode.
• Visible damage: the Getting Started checklist (partials/overview.html:96-117) renders native gray outset buttons in both themes; 32 visible buttons on the Plugin Manager page render with default browser chrome; search icons overlap inputs; error/diff modal backdrops are transparent (bg-gray-500 bg-opacity-75 undefined).

Other drift:

• Four competing showNotification definitions (app.js:6, app-shell.js:2464, widgets/notification.js:298, partials/fonts.html:249) — the winner depends on load order — plus 53 alert()/confirm() calls.
• At least four modal implementations (on-demand modal in base.html:1032, Tailwind-UI style in error_handler.js/diff_viewer.js, .jfm-*/.pfm-* with injected CSS, ad-hoc modals in plugins_manager.js).
• .btn mixed with ~90 hand-assembled color-utility button combos.
• SSE wiring duplicated in app-shell.js:5-60 and app.js:186-205.

Findings by severity

P0

Undefined utility layer (above). Every show/hide toggle and every layout built from missing classes silently fails; root cause of most visual bugs. Fix: replace the hand-rolled subset with a real, purged Tailwind build (with dark-mode variants), or at minimum define the high-use missing classes (hidden, border, block, spacing/text utilities) and a button reset. → /impeccable harden

P1

• Focus rings never render. focus:ring-2 (app.css:289-291) references --tw-ring-inset and --tw-ring-offset-width, which are never defined, so the box-shadow is invalid. focus:outline-none (18 uses) does remove the outline. peer-focus:ring-4 has no rule, so the plugin enable toggle (plugins_manager.js:1586-1593, sr-only checkbox) shows no focus. WCAG 2.4.7.
• Modals lack dialog semantics. Only json-file-manager.js has role="dialog"/aria-modal/Escape/initial focus; none trap focus or return it. On-demand (base.html:1032), error (error_handler.js:164-205), diff (diff_viewer.js:211-214), plugin file manager (plugin-file-manager.js:372-392, 576-599), array-table editor (array-table.js:460-467) have none of it. WCAG 2.1.2 / 4.1.2.
• Unnamed controls. ~16 icon-only buttons with no accessible name, e.g. base.html:1036, plugins.html:173,210, plugin_config.html:485,656, number-input.js:102,129, text-input.js:120, date-picker.js:95, time-picker.js:100, password-input.js:141. ~115 of 245 form fields have no label (hotspots: plugin_config.html 19, starlark_config.html 14, plugins.html 11); confirmed live on the 11 store search/sort/filter inputs.
• Captive WiFi setup page (first-run surface): #msg status has no live region, and outline:none is replaced by a 15%-alpha shadow (captive_setup.html:16,48).
• Background traffic never stops. /stream/stats and /stream/display SSE stay open on every tab (display frames push with no preview visible). Tab timers keep running after leaving the tab (display.html:1046 5s, logs.html:222 5s, tools.html:987 15s, plugins_manager.js:1882 15s, update check base.html:1196 30min). Only tools.html:999 checks visibilitychange. Costly on a Pi Zero 2 W.
• Page weight. 47 script tags on every page, including all 33 widgets (base.html:984-1018). app-shell.js (177 KB) is render-blocking (base.html:956); plugins_manager.js is 277 KB.
• Dark mode leaks. plugin-file-manager.js (53 hex) and json-file-manager.js (63 hex, e.g. .jfm-modal-box{background:#fff}) inject CSS that ignores data-theme; .form-control hard-codes #fff/#111827 (app.css:668-671). app.css has 186 hex + 46 rgb literals vs 94 var(--…) uses.

P2

• Toasts: role="alert" inside an aria-live="polite" container (notification.js:78,156) → double/assertive announcements; auto-dismiss 4s.
• prefers-reduced-motion covers 3 animations; ~106 animate-pulse/fa-spin uses, modalSlideIn, and toast slides ignore it.
• Mobile: header title wraps to three lines and spills out of the header; ~33 plugin-card buttons are text-xs px-2 py-1 (~24px); #logs-container forced to 400/350px with !important (app.css:399-411).
• Logs panel contrast: text-gray-400 on bg-gray-900 ≈ 3.9:1 (logs.html:75,86).
• Three unnamed nested <nav> landmarks (base.html:474,477,548); no skip link.
• Plugin lists fully rebuilt via innerHTML on every filter change (plugins_manager.js:1554, 3784, 3993, 4389, 5905); logs.html:225 adds a reflow-forcing resize listener on every partial load.

P3

• No loading="lazy" on images; Font Awesome font-display:block.
• Unpinned alpinejs@3.x.x unpkg fallback (base.html:241).
• widgets/example-color-picker.js is not loaded anywhere.
• Detector: 3px accent stripe on .plugin-card::before (app.css:721).

Verified and rejected

• "Static assets are never cache-busted" (raised as P0): false. app.py:491 (@app.url_defaults add_static_version) appends file mtime as ?v= to every static URL; the live HTML confirms it. The manual ?v=20260307 on two script tags is merely redundant.
• Light-mode gray text contrast is mostly fine: app.css remaps grays darker (4.8–10:1).
• Detector gray-on-color hits at app.css:84,285 and broken-image hits (JS-populated src) are not real rendered issues.

What works

• Theme set before first paint, follows OS preference, data-theme + tokens.
• Mobile drawer: Escape closes it, focus returns to the hamburger, 44px rows.
• aria-current="page" on nav tabs; real <header> and <main>.
• Status colors always paired with text; nearly all images have alt text.
• toggle-switch.js uses role="switch"; vendor assets self-hosted.

Open decisions (block the P0 fix approach)

Recorded as undecided in PRODUCT.md:

• Must the UI work fully offline (no CDN fallbacks)?
• Is a Node/CSS build step acceptable for contributors?
• Is WCAG 2.2 AA a formal requirement?

Recommended order

1. [P0] /impeccable harden — fix the utility layer (real Tailwind build or define missing classes + button reset).
2. [P1] /impeccable harden — focus-ring variables and peer-focus; one shared accessible modal helper; name icon buttons and label fields; live region on the captive page.
3. [P1] /impeccable optimize — pause SSE/timers on hidden tab or page; load widget scripts on demand.
4. [P1] /impeccable colorize — move file-manager CSS and .form-control onto theme tokens.
5. [P2] /impeccable adapt — header wrap, touch targets, log height.
6. [P2] /impeccable animate — reduced-motion alternatives.
7. /impeccable polish — final pass.