Fixes #523: Add some style

pwnagotchi/ui/web/static/js/viewportHeight.js

@@ -0,0 +1,17 @@
+/* https://css-tricks.com/the-trick-to-viewport-units-on-mobile/*/
+
+var lastViewportHeight;
+
+function updateViewportSize() {
+  // First we get the viewport height and we multiple it by 1% to get a value for a vh unit
+  var vh = window.innerHeight * 0.01;
+  if (!lastViewportHeight || lastViewportHeight !== vh) {
+    // Then we set the value in the --vh custom property to the root of the document
+    document.documentElement.style.setProperty("--vh", vh + "px");
+    lastViewportHeight = vh;
+  }
+}
+
+document.addEventListener("DOMContentLoaded", function() {
+  updateViewportSize();
+});