diff --git a/assets/css/player.css b/assets/css/player.css
index 9cb400ad..60f3ce73 100644
--- a/assets/css/player.css
+++ b/assets/css/player.css
@@ -71,8 +71,10 @@
   padding-top: 2em
 }
 
-.video-js.player-style-youtube .vjs-progress-control .vjs-progress-holder, .video-js.player-style-youtube .vjs-progress-control {height: 5px;
-margin-bottom: 10px;}
+.video-js.player-style-youtube .vjs-progress-control .vjs-progress-holder, .video-js.player-style-youtube .vjs-progress-control {
+  height: 5px;
+  margin-bottom: 10px;
+}
 
 ul.vjs-menu-content::-webkit-scrollbar {
   display: none;
@@ -86,6 +88,7 @@ ul.vjs-menu-content::-webkit-scrollbar {
   background-color: rgba(0, 0, 0, 0.75) !important;
   border-radius: 9px !important;
   padding: 5px !important;
+  line-height: 1.5 !important;
 }
 
 .vjs-play-control,
diff --git a/assets/js/player.js b/assets/js/player.js
index f32c9b56..920a5470 100644
--- a/assets/js/player.js
+++ b/assets/js/player.js
@@ -5,6 +5,9 @@ var video_data = JSON.parse(document.getElementById('video_data').textContent);
 var options = {
     liveui: true,
     playbackRates: [0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0],
+    fontPercent: [0.5, 0.75, 1.25, 1.5, 1.75, 2, 3, 4],
+    windowOpacity: ['0', '0.5', '1'],
+    textOpacity: ['0.5', '1'],
     controlBar: {
         children: [
             'playToggle',
@@ -585,6 +588,13 @@ const toggle_captions = (function () {
     };
 })();
 
+// For real-time updates to captions (if currently showing)
+function update_captions() {
+    if (document.body.querySelector('.vjs-text-track-cue')) {
+        toggle_captions(); toggle_captions();
+    }
+}
+
 function toggle_fullscreen() {
     player.isFullscreen() ? player.exitFullscreen() : player.requestFullscreen();
 }
@@ -597,6 +607,34 @@ function increase_playback_rate(steps) {
     player.playbackRate(options.playbackRates[newIndex]);
 }
 
+function increase_caption_size(steps) {
+    const maxIndex = options.fontPercent.length - 1;
+    const fontPercent = player.textTrackSettings.getValues().fontPercent || 1.25;
+    const curIndex = options.fontPercent.indexOf(fontPercent);
+    let newIndex = curIndex + steps;
+    newIndex = helpers.clamp(newIndex, 0, maxIndex);
+    player.textTrackSettings.setValues({ fontPercent: options.fontPercent[newIndex] });
+    update_captions();
+}
+
+function toggle_caption_window() {
+    const numOptions = options.windowOpacity.length;
+    const windowOpacity = player.textTrackSettings.getValues().windowOpacity || '0';
+    const curIndex = options.windowOpacity.indexOf(windowOpacity);
+    const newIndex = (curIndex + 1) % numOptions;
+    player.textTrackSettings.setValues({ windowOpacity: options.windowOpacity[newIndex] });
+    update_captions();
+}
+  
+function toggle_caption_opacity() {
+    const numOptions = options.textOpacity.length;
+    const textOpacity = player.textTrackSettings.getValues().textOpacity || '1';
+    const curIndex = options.textOpacity.indexOf(textOpacity);
+    const newIndex = (curIndex + 1) % numOptions;
+    player.textTrackSettings.setValues({ textOpacity: options.textOpacity[newIndex] });
+    update_captions();
+}
+
 addEventListener('keydown', function (e) {
     if (e.target.tagName.toLowerCase() === 'input') {
         // Ignore input when focus is on certain elements, e.g. form fields.
@@ -692,6 +730,12 @@ addEventListener('keydown', function (e) {
 
         case '>': action = increase_playback_rate.bind(this, 1); break;
         case '<': action = increase_playback_rate.bind(this, -1); break;
+        
+        case '=': action = increase_caption_size.bind(this, 1); break;
+        case '-': action = increase_caption_size.bind(this, -1); break;
+
+        case 'w': action = toggle_caption_window; break;
+        case 'o': action = toggle_caption_opacity; break;
 
         default:
             console.info('Unhandled key down event: %s:', decoratedKey, e);