Custom CSS support

AppApi.cs

@@ -394,6 +394,15 @@ namespace VRCX
             return System.Text.Json.JsonSerializer.Serialize<VRCEventDeserialization.EventEntry>(eventData);
         }
 
+        public string CustomCssPath()
+        {
+            var output = String.Empty;
+            var filePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "VRCX\\custom.css");
+            if (File.Exists(filePath))
+                output = filePath;
+            return output;
+        }
+
         public void SetStartup(bool enabled)
         {
             try

html/src/app.js

@@ -73,6 +73,8 @@ speechSynthesis.getVoices();
             } else if (e.key === 'r') {
                 location.reload();
             }
+        } else if (e.key === 'R') {
+            $app.refreshCustomCss();
         }
     });
 
@@ -4055,6 +4057,7 @@ speechSynthesis.getVoices();
             API.$on('SHOW_LAUNCH_DIALOG', (tag) => this.showLaunchDialog(tag));
             this.updateLoop();
             this.getGameLogTable();
+            this.refreshCustomCss();
             this.$nextTick(function () {
                 this.$el.style.display = '';
                 if (!this.enablePrimaryPassword) {
@@ -4077,6 +4080,22 @@ speechSynthesis.getVoices();
         }
     };
 
+    $app.methods.refreshCustomCss = function () {
+        if (document.contains(document.getElementById('app-custom-style'))) {
+            document.getElementById('app-custom-style').remove();
+        }
+        AppApi.CustomCssPath().then((customCss) => {
+            var head = document.head;
+            if (customCss) {
+                var $appCustomStyle = document.createElement('link');
+                $appCustomStyle.setAttribute('id', 'app-custom-style');
+                $appCustomStyle.rel = 'stylesheet';
+                $appCustomStyle.href = `file://${customCss}?_=${Date.now()}`;
+                head.appendChild($appCustomStyle);
+            }
+        });
+    };
+
     $app.methods.openExternalLink = function (link) {
         this.$confirm(`${link}`, 'Open External Link', {
             confirmButtonText: 'Confirm',