[JFWooten4]

Summary

The PDF viewer stopped rounding the page corners whenever a desktop split pane narrowed to 720px or less. The narrow-layout CSS explicitly set border-radius: 0 and removed all horizontal page clearance, which made the accent outline appear square and vulnerable to edge clipping.

• Retain the shared 8px page radius (including canvases/previews that inherit it), rather than forcing square page edges at the narrow breakpoint.
• Use a modest 8px horizontal gutter below 720px to preserve the themed 1px outline without reverting to the full 16px desktop gutter.
• Leave the PDF zoom sizing and toolbar responsiveness unchanged.
• Replace the previous edge-to-edge CSS assertion with regression coverage for the radius, colored outline, gutter, and absence of a narrow .page override.

Reproduction

1. Open a multi-page PDF in a horizontally compressed viewer pane narrower than 720px.
2. Look at the page's upper corners and side outlines.
3. Before: corners are square despite rounded pages at wider widths. After: the same rounded treatment remains visible in the narrow pane.

Validation

• Verified the resulting Git tree differs from its parent and contains both intended modified files.
• Verified the branch is one commit ahead of main, zero behind, with only the CSS and regression-test changes.
• Checked the updated CSS against the intended narrow-layout assertions before committing.
• Not run: complete Node tests or an installed-browser visual check; repository checkout network access was unavailable in this session.

Related history

• #134 introduced the narrow-width square-corner and full-bleed rules.
• #146 made page canvases/previews inherit the container's rounding.