style(home): full-viewport-height video hero (100vh) with vertical centering

Hero section now min-height: 100vh — fills the entire viewport, content
vertically centered via flex-column + justify-content: center. Scrolling
reveals the rest of the page below (3-pillars cards, industries, etc.).

Replaces the previous fixed-padding approach (9rem top, 8rem bottom) which
left visible space below the hero on tall monitors and forced the hero
shorter on mobile.

Padding kept minimal (2rem top/bottom) for breathing room when content
gets close to the viewport edges on very short displays.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tools/av-generate-home.php

@@ -263,17 +263,19 @@ function av_build_home_video_hero() {
 
     $els = [];
 
-    // SECTION — full bleed, large vertical padding, video bg or navy
+    // SECTION — full-bleed, 100vh tall, content vertically centered.
+    // Using min-height (not fixed height) so content can still extend if needed.
+    // 100dvh fallback handles mobile address bar collapse correctly (newer browsers).
     $els[] = [
         'id' => $sid, 'name' => 'section', 'parent' => 0, 'children' => [$oct],
         'settings' => [
-            '_padding'                  => av_sp('9rem', '0', '8rem', '0'),
-            '_padding:tablet_portrait'  => av_sp('7rem', '0', '6rem', '0'),
-            '_padding:mobile_landscape' => av_sp('5rem', '0', '4rem', '0'),
-            '_padding:mobile_portrait'  => av_sp('4rem', '0', '3.5rem', '0'),
+            '_padding'      => av_sp('2rem', '0', '2rem', '0'),  // breathing room at top/bottom
+            '_heightMin'    => '100vh',                          // full viewport height
+            '_justifyContent' => 'center',                       // vertical centering (flex-column)
             '_background'   => $section_background,
             '_position'     => 'relative',
             '_overflow'     => 'hidden',
+            '_cssCustom'    => '%root% { min-height: 100vh; min-height: 100dvh; }',
         ],
     ];