Make the app root fill at least the full height of the viewport, and
make the main content grow to fill the empty space - aligning the footer
with the bottom of the page at all times.
The iOS-compatible video may not be the best quality. Add a separate quality option to accommodate people who want the best available versus the best compatible with iOS's strict requirements.
Testing with https://www.youtube.com/watch?v=YiRMs5ZhcH4 where the best quality video is 2160p and not iOS-compatible.
With best quality, the VP9 video format is used (better quality but not iOS-compatible):
```
% ffprobe -hide_banner Who\ Can\ Find\ the\ Weirdest\ PC\ Parts\ on\ AliExpress？.mp4
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Who Can Find the Weirdest PC Parts on AliExpress？.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
encoder : Lavf60.16.100
Duration: 00:19:02.72, start: 0.000000, bitrate: 10941 kb/s
Stream #0:0[0x1](und): Video: vp9 (Profile 0) (vp09 / 0x39307076), yuv420p(tv, bt709), 3840x1920, 10805 kb/s, 29.97 fps, 29.97 tbr, 16k tbn (default)
Metadata:
handler_name : ISO Media file produced by Google Inc. Created on: 06/15/2024.
vendor_id : [0][0][0][0]
Stream #0:1[0x2](eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
handler_name : ISO Media file produced by Google Inc.
vendor_id : [0][0][0][0]
```
With "Best (iOS)" quality, the H264 video (lower quality but iOS-compatible) is used:
```
% ffprobe -hide_banner Who\ Can\ Find\ the\ Weirdest\ PC\ Parts\ on\ AliExpress？.mp4
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Who Can Find the Weirdest PC Parts on AliExpress？.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf60.16.100
Duration: 00:19:02.72, start: 0.000000, bitrate: 1846 kb/s
Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1920x960 [SAR 1:1 DAR 2:1], 1710 kb/s, 29.97 fps, 29.97 tbr, 30k tbn (default)
Metadata:
handler_name : ISO Media file produced by Google Inc.
vendor_id : [0][0][0][0]
Stream #0:1[0x2](eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
handler_name : ISO Media file produced by Google Inc.
vendor_id : [0][0][0][0]
```
Included a README note about the new quality option.
