Field note 01 · layout
I moved the display-size slider one notch above the default on a cheap Android phone, and an H5 game that fitted the screen the night before lost its right edge. The browser had started reporting a narrower viewport.
Two numbers matter: the CSS width the page is told about, and the device pixel ratio. The same 1080-pixel panel can be told 412 or 360 pixels wide, so a canvas sized from window.innerWidth only follows the smaller figure if it listens for the change.
My test: open the page, note the width, drag the slider mid-session, check whether the buttons return. One bookmarked reference page, c8vip apk, keeps its strip against the right edge at the default and loses it above that until a reload.
Games that survive recompute from a real measurement after a resize event instead of trusting the size they saw at start-up. The ones that fail wrap everything in a fixed-pixel container, so the scene and HUD slide left and stay there. I hit that on 8qr apk.
Font scale is the other half, hiding in another menu. The largest system font size grows rem-based text in H5 interfaces, spreading rows until they cover the play area; a page like sr996 apk that mixes rem spacing with a fixed-height canvas shows it at once.
Anything with a chat box adds the keyboard. On biwin apk the soft keyboard cut the visible height enough that the bottom controls sat underneath it, and they stayed there after it closed, because the layout cached the smaller height.
None of that is a reason to avoid browser games. It is a reason to fix display and font size first, then judge the page. day777 is what I keep open while changing settings.
The slider is a setting nobody tests.
Typed on the handset. Static page: no scripts, no cookies, no trackers.