Modals and dialogs are usable on mobile screens

A modal with width: 600px on a 375px phone renders with its right edge off-screen, clipping the close button and any right-aligned action buttons. If the close mechanism is off-screen, the user has no way to dismiss the modal except reloading. Modals also commonly lack overflow-y: auto, so long content gets clipped at the bottom of the viewport with no scroll to reach the submit button. Both failure modes trap users.

Constrain modal width to 90vw with a max-width for desktop, cap height at 90vh, and enable overflow-y: auto on the content. In shadcn/ui, apply these as classes on DialogContent. Audit any modal or dialog components in src/components/ui/.

<DialogContent className="w-[90vw] max-w-lg max-h-[90vh] overflow-y-auto">

• ID: mobile-responsiveness.mobile-ux.mobile-modals

• Severity: low

• What to look for: Examine modal and dialog components. Check their sizing: fixed pixel widths larger than typical phone viewports (>640px), fixed heights that exceed phone viewport heights, or lack of overflow-y: auto on modal content. Check whether modals have a close mechanism that works on touch. Look for modals that position content off-center on mobile due to centering patterns without max-width: calc(100vw - 2rem) constraints.

• Pass criteria: Count all modal, dialog, and overlay components in the codebase (<dialog>, modal library components, elements with position: fixed or position: absolute covering the viewport). For each, verify 3 requirements: (1) responsive sizing (max-width: 90vw or max-width: calc(100vw - 2rem) or similar), (2) content scrolls if needed (overflow-y: auto), (3) touch-accessible close mechanism (visible close button of at least 44x44px). Report: "X of Y modals meet all 3 mobile requirements."

• Fail criteria: At least 1 modal has a fixed width exceeding 640px without a responsive max-width constraint, or is positioned such that it extends off-screen on phones below 640px width.

• Skip (N/A) when: No modal, dialog, or overlay components detected in the codebase — 0 modals found (no <dialog>, no modal libraries, no elements with position: fixed or position: absolute covering the viewport).

• Detail on fail: "Modal in components/ui/modal.tsx has fixed width of 600px with no max-width constraint — 1 of 3 modals will overflow phone viewports below 640px".

• Remediation:

  .modal {
    width: 90vw;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    margin: auto;
  }
  

  In Tailwind with shadcn/ui:

  <DialogContent className="w-[90vw] max-w-lg max-h-[90vh] overflow-y-auto">