Fix Share button truncation in iPad portrait mode

[Copilot]

The Share button in tutorial detail modals was truncated on iPad portrait and other narrow viewports due to inline layout overflow in constrained columns.

Changes

• Tablet breakpoint (768-991px): Stack YouTube and Share buttons vertically with display: block and width: 100%
• Mobile breakpoint (≤767px): Apply same vertical layout with reduced sizing
• Use increased CSS specificity (.column.six.wide .yt-button.button.large) to avoid !important declarations

.detailview {
    .column.six.wide .yt-button.button.large,
    .column.six.wide button.home-share-button.button.large {
        display: block;
        width: 100%;
        margin-bottom: 0.5rem;
        font-size: 1rem;
        padding: 0.7rem 1rem;
    }
}

Desktop layout (≥992px) unchanged - buttons remain side-by-side.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[iPad] The "Share" button was cut in iPad portrait mode</issue_title>
<issue_description>Describe the bug
The “Share” button is partially obscured when viewing in portrait mode on iPad.

Steps to reproduce the behavior:
1.Open the Microsoft MakeCode Arcade on iPad.
2.Switch the device to portrait orientation.
3.Click Tony Albatross: Pro Dolphin under Advanced Livestream tutorial section.
4.Observe the "Share" button.

Actual behavior
The "Share" button was cut in iPad portrait mode.

Expected behavior
The “Share" should display completely and be fully tappable.

Screenshots

Additional context
1.OS: iPad Pro 11 18.7.3
2.Browser: Safari
3.Arcade version : 2.1.25
4.Microsoft MakeCode version: 12.2.15</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [iPad] The "Share" button was cut in iPad portrait mode pxt-arcade#7294

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.