diff --git a/src/App.css b/src/App.css
index 78a1a3e..0b08c8b 100644
--- a/src/App.css
+++ b/src/App.css
@@ -110,6 +110,12 @@
   padding: 2px 8px;
   border-radius: 4px;
   font-size: 0.8rem;
+  color: var(--color-text-main);
+}
+
+/* Force button colors to ensure dark mode visibility */
+button {
+  color: var(--color-text-main);
 }
 
 /* Pitch Monitor Bar */
@@ -341,4 +347,154 @@
   color: var(--color-text-main);
   border-color: var(--color-text-main);
   transform: scale(1.05);
+}
+
+/* Help Popup */
+.help-popup-overlay {
+  position: fixed;
+  top: 0;
+  left: 0;
+  width: 100vw;
+  height: 100vh;
+  background-color: rgba(0, 0, 0, 0.5);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: 200;
+  backdrop-filter: blur(4px);
+  animation: fadeIn 0.2s ease-out;
+}
+
+.help-popup {
+  background-color: var(--color-surface);
+  padding: var(--spacing-lg);
+  border-radius: var(--radius-lg);
+  box-shadow: var(--shadow-lg);
+  max-width: 400px;
+  width: 90%;
+  position: relative;
+  border: 1px solid rgba(128, 128, 128, 0.1);
+}
+
+.help-item {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: var(--spacing-sm);
+  padding-bottom: var(--spacing-sm);
+  border-bottom: 1px solid rgba(128, 128, 128, 0.1);
+}
+
+.help-item:last-child {
+  border-bottom: none;
+  margin-bottom: 0;
+  padding-bottom: 0;
+}
+
+.shortcut-key {
+  background-color: var(--color-bg);
+  border: 1px solid rgba(128, 128, 128, 0.2);
+  padding: 2px 8px;
+  border-radius: 4px;
+  font-family: monospace;
+  font-weight: bold;
+  color: var(--color-text-main);
+}
+
+.help-close {
+  position: absolute;
+  top: 10px;
+  right: 10px;
+  background: none;
+  border: none;
+  cursor: pointer;
+  color: var(--color-text-muted);
+}
+
+.help-close:hover {
+  color: var(--color-text-main);
+}
+
+@keyframes fadeIn {
+  from {
+    opacity: 0;
+  }
+
+  to {
+    opacity: 1;
+  }
+}
+
+/* Header Adjustments */
+.app-header-left {
+  display: flex;
+  flex-direction: column;
+}
+
+.app-subtitle {
+  font-size: 0.8rem;
+  font-weight: 500;
+  color: var(--color-text-muted);
+  margin-top: -4px;
+}
+
+.app-subtitle a {
+  color: var(--color-primary);
+  text-decoration: none;
+  transition: color 0.2s;
+}
+
+.app-subtitle a:hover {
+  color: var(--color-primary-dark);
+  text-decoration: underline;
+}
+
+.header-controls {
+  display: flex;
+  gap: var(--spacing-sm);
+  align-items: center;
+}
+
+.icon-button {
+  background: none;
+  border: none;
+  cursor: pointer;
+  color: var(--color-text-muted);
+  padding: 8px;
+  border-radius: 50%;
+  transition: all 0.2s;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+
+.icon-button:hover {
+  background-color: rgba(128, 128, 128, 0.1);
+  color: var(--color-text-main);
+}
+
+.game-mode-toggle {
+  display: flex;
+  background-color: var(--color-bg);
+  padding: 2px;
+  border-radius: 20px;
+  border: 1px solid rgba(128, 128, 128, 0.1);
+}
+
+.toggle-option {
+  padding: 4px 12px;
+  border-radius: 16px;
+  font-size: 0.85rem;
+  font-weight: 600;
+  cursor: pointer;
+  background: transparent;
+  border: none;
+  color: var(--color-text-muted);
+  transition: all 0.2s;
+}
+
+.toggle-option.active {
+  background-color: var(--color-surface);
+  color: var(--color-primary);
+  box-shadow: var(--shadow-sm);
 }
\ No newline at end of file
diff --git a/src/App.tsx b/src/App.tsx
index 1b21bac..7128a9e 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -15,7 +15,7 @@ import {
 import { INSTRUMENT_DEFINITIONS } from './music/InstrumentConfigs';
 import { FretboardHint } from './components/FretboardHint';
 import { TuningMeter } from './components/TuningMeter';
-import { Mic, MicOff, SkipForward, HelpCircle, Volume2 } from 'lucide-react';
+import { Mic, MicOff, SkipForward, HelpCircle, Volume2, X } from 'lucide-react';
 import './App.css';
 import './styles/skip-button.css';
 
@@ -185,6 +185,47 @@ function App() {
     }
   }, [pitchData, targetMidi, matchStartTime, generateNewNote, settings.rhythm, restartMetronome, feedbackMessage]);
 
+  /* Keyboard Shortcuts */
+  const [showHelp, setShowHelp] = useState(false);
+
+  useEffect(() => {
+    const handleKeyDown = (e: KeyboardEvent) => {
+      // Ignore if typing in an input
+      if (e.target instanceof HTMLInputElement || e.target instanceof HTMLTextAreaElement) return;
+
+      // prevent default for space to stop scrolling
+      if (e.code === 'Space') {
+        e.preventDefault();
+      }
+
+      switch (e.key.toLowerCase()) {
+        case 'h':
+          setSettings(s => ({ ...s, showHint: !s.showHint }));
+          break;
+        case 'z':
+          setSettings(s => ({ ...s, zenMode: !s.zenMode }));
+          break;
+        case 'r': // Replay
+        case 'p': // Play
+          playNote(targetMidi, 1.0);
+          break;
+      }
+
+      // Check non-character keys via code to avoid layout issues for function keys
+      if (e.code === 'Space' || e.code === 'Enter') {
+        generateNewNote();
+      }
+
+      if (e.code === 'Escape') {
+        if (showHelp) setShowHelp(false);
+        else if (settings.zenMode) setSettings(s => ({ ...s, zenMode: false }));
+      }
+    };
+
+    window.addEventListener('keydown', handleKeyDown);
+    return () => window.removeEventListener('keydown', handleKeyDown);
+  }, [settings.zenMode, showHelp, generateNewNote, playNote, targetMidi]);
+
   // Hint text construction
   const hintPositions = useMemo(() => {
     if (!settings.showHint) return [];
@@ -197,7 +238,37 @@ function App() {
     <div className={`app-container ${settings.zenMode ? 'zen-mode' : ''}`}>
       {!settings.zenMode && (
         <header className="app-header">
-          <div className="logo">Sheet music trainer</div>
+          <div className="app-header-left">
+            <div className="logo">Sheet music trainer</div>
+            <div className="app-subtitle">
+              <a href="http://jensmohrmann.de" target="_blank" rel="noopener noreferrer">jensmohrmann.de</a>
+            </div>
+          </div>
+
+          <div className="header-controls">
+            <div className="game-mode-toggle">
+              <button
+                className={`toggle-option ${settings.gameMode === 'sight_reading' ? 'active' : ''}`}
+                onClick={() => setSettings(s => ({ ...s, gameMode: 'sight_reading' }))}
+              >
+                Sight Reading
+              </button>
+              <button
+                className={`toggle-option ${settings.gameMode === 'ear_training' ? 'active' : ''}`}
+                onClick={() => setSettings(s => ({ ...s, gameMode: 'ear_training' }))}
+              >
+                Ear Training
+              </button>
+            </div>
+
+            <button
+              className="icon-button"
+              onClick={() => setShowHelp(true)}
+              title="Shortcuts Help"
+            >
+              <HelpCircle size={24} />
+            </button>
+          </div>
         </header>
       )}
 
@@ -257,21 +328,15 @@ function App() {
               <button
                 className={`hint-button ${settings.showHint ? 'active' : ''}`}
                 onClick={() => setSettings(s => ({ ...s, showHint: !s.showHint }))}
+                title="Keyboard Shortcut: H"
               >
                 <HelpCircle size={18} />
                 {settings.showHint ? "Hide Hint" : "Show Hint"}
               </button>
-              <button className="skip-button" onClick={generateNewNote}>
+              <button className="skip-button" onClick={generateNewNote} title="Keyboard Shortcut: Space">
                 <SkipForward size={18} />
                 Skip Note
               </button>
-              <button
-                className="zen-button"
-                onClick={() => setSettings(s => ({ ...s, zenMode: true }))}
-                title="Zen Mode"
-              >
-                <span>Zen</span>
-              </button>
             </div>
           )}
         </div>
@@ -316,16 +381,45 @@ function App() {
       )
       }
 
-      {
-        settings.zenMode && (
-          <button
-            className="exit-zen-button"
-            onClick={() => setSettings(s => ({ ...s, zenMode: false }))}
-          >
-            Exit Zen Mode
-          </button>
-        )
-      }
+      {/* Floating Zen Mode Button (Toggle) */}
+      <button
+        className="exit-zen-button"
+        onClick={() => setSettings(s => ({ ...s, zenMode: !s.zenMode }))}
+        title="Keyboard Shortcut: Z"
+      >
+        {settings.zenMode ? "Exit Zen Mode" : "Zen Mode"}
+      </button>
+
+      {/* Help Popup */}
+      {showHelp && (
+        <div className="help-popup-overlay" onClick={() => setShowHelp(false)}>
+          <div className="help-popup" onClick={e => e.stopPropagation()}>
+            <button className="help-close" onClick={() => setShowHelp(false)}><X size={20} /></button>
+            <h2 style={{ marginTop: 0, marginBottom: '24px' }}>Keyboard Shortcuts</h2>
+
+            <div className="help-item">
+              <span>Skip Note</span>
+              <span className="shortcut-key">Space</span>
+            </div>
+            <div className="help-item">
+              <span>Toggle Hint</span>
+              <span className="shortcut-key">H</span>
+            </div>
+            <div className="help-item">
+              <span>Toggle Zen Mode</span>
+              <span className="shortcut-key">Z</span>
+            </div>
+            <div className="help-item">
+              <span>Replay Note</span>
+              <span className="shortcut-key">R</span>
+            </div>
+            <div className="help-item">
+              <span>Close Help / Exit Zen</span>
+              <span className="shortcut-key">Esc</span>
+            </div>
+          </div>
+        </div>
+      )}
     </div >
   );
 }
diff --git a/src/components/Controls.tsx b/src/components/Controls.tsx
index cb822de..edb523b 100644
--- a/src/components/Controls.tsx
+++ b/src/components/Controls.tsx
@@ -152,27 +152,7 @@ export const Controls: React.FC<ControlsProps> = ({ settings, onUpdateSettings }
                 </select>
             </div>
 
-            <div className="control-group" style={{ borderTop: '1px solid rgba(255,255,255,0.1)', paddingTop: '12px', marginTop: '12px', width: '100%' }}>
-                <label className="control-label" style={{ marginBottom: '8px' }}>
-                    <span>Game Mode</span>
-                </label>
-                <div style={{ display: 'flex', gap: '8px' }}>
-                    <button
-                        className={`control-button ${settings.gameMode === 'sight_reading' ? 'active' : ''}`}
-                        onClick={() => onUpdateSettings({ ...settings, gameMode: 'sight_reading' })}
-                        style={{ flex: 1 }}
-                    >
-                        Sight Reading
-                    </button>
-                    <button
-                        className={`control-button ${settings.gameMode === 'ear_training' ? 'active' : ''}`}
-                        onClick={() => onUpdateSettings({ ...settings, gameMode: 'ear_training' })}
-                        style={{ flex: 1 }}
-                    >
-                        Ear Training
-                    </button>
-                </div>
-            </div>
+
 
             {/* Rhythm Controls */}
             <div className="control-group rhythm-group" style={{ borderTop: '1px solid rgba(255,255,255,0.1)', paddingTop: '12px', marginTop: '12px', width: '100%' }}>
diff --git a/src/components/SheetMusic.tsx b/src/components/SheetMusic.tsx
index e7cca5c..0fc4e85 100644
--- a/src/components/SheetMusic.tsx
+++ b/src/components/SheetMusic.tsx
@@ -36,6 +36,14 @@ export const SheetMusic: React.FC<SheetMusicProps> = ({
         renderer.resize(width, height);
         const context = renderer.getContext();
 
+        // IMPORTANT: Set global styles for the context to ensure everything draws with correct color
+        // VexFlow uses context properties for default colors.
+        // We can't easily extract CSS var value here without getComputedStyle, which is expensive inside render.
+        // However, VexFlow SVGContext just adds attributes. 
+        // We can set fillStyle/strokeStyle to the var string.
+        context.setFillStyle("var(--color-text-main)");
+        context.setStrokeStyle("var(--color-text-main)");
+
         // --- Helper: Decide which clef a note belongs to in Grand Staff ---
         // For Grand Staff: usually Split at Middle C (C4 / Midi 60). 
         // >= 60 -> Treble, < 60 -> Bass.
@@ -45,6 +53,7 @@ export const SheetMusic: React.FC<SheetMusicProps> = ({
 
         let staves: Record<string, Stave> = {};
 
+
         if (clef === 'grand') {
             // Create Treble Stave
             const topStave = new Stave(20, 40, width - 30);
@@ -97,8 +106,15 @@ export const SheetMusic: React.FC<SheetMusicProps> = ({
                 clef: noteClef as 'treble' | 'bass'
             });
 
+            // Set styles for all notes to use CSS variables if not colored specifically
+            staveNote.setStyle({ fillStyle: "var(--color-text-main)", strokeStyle: "var(--color-text-main)" });
+
             if (data.accidental) {
-                staveNote.addModifier(new Accidental(data.accidental));
+                const accidental = new Accidental(data.accidental);
+                // Ensure accidentals also use the color
+                // VexFlow 4 might not inherit automatically in all contexts, but good to be safe. 
+                // However, StaveNote.setStyle usually propagates.
+                staveNote.addModifier(accidental);
             }
 
             if (type === 'played') {
@@ -131,7 +147,14 @@ export const SheetMusic: React.FC<SheetMusicProps> = ({
             });
 
             // Add a Question Mark Annotation
-            ghost.addModifier(new Annotation("?").setVerticalJustification(Annotation.VerticalJustify.CENTER));
+            const annotation = new Annotation("?");
+            annotation.setVerticalJustification(Annotation.VerticalJustify.CENTER);
+            // Annotations don't natively support setStyle in older VexFlow, but let's see. 
+            // In VexFlow 4, Font settings are different. 
+            // We can try to rely on current contexts or just standard fill. 
+            // Actually, context fillStyle affects it.
+
+            ghost.addModifier(annotation);
 
             targetObj = { note: ghost, clef: noteClef };
         } else {
diff --git a/src/styles/variables.css b/src/styles/variables.css
index 8e68535..66d1c50 100644
--- a/src/styles/variables.css
+++ b/src/styles/variables.css
@@ -11,9 +11,10 @@
   --color-primary-dark: hsl(var(--hue-primary), 60%, 40%);
   --color-text-main: hsl(var(--hue-text), 20%, 20%);
   --color-text-muted: hsl(var(--hue-text), 10%, 60%);
-  
+
   --color-success: hsl(var(--hue-success), 60%, 45%);
   --color-error: hsl(var(--hue-error), 70%, 55%);
+  --color-warning: hsl(35, 90%, 50%);
 
   /* Spacing */
   --spacing-xs: 4px;
@@ -29,11 +30,11 @@
   --font-size-lg: 1.25rem;
   --font-size-xl: 1.5rem;
   --font-size-2xl: 2rem;
-  
+
   /* Shadows */
-  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
-  --shadow-md: 0 4px 6px rgba(0,0,0,0.05), 0 1px 3px rgba(0,0,0,0.1);
-  --shadow-lg: 0 10px 15px rgba(0,0,0,0.05), 0 4px 6px rgba(0,0,0,0.02);
+  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
+  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.05), 0 1px 3px rgba(0, 0, 0, 0.1);
+  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.05), 0 4px 6px rgba(0, 0, 0, 0.02);
 
   /* Radius */
   --radius-sm: 6px;
@@ -51,16 +52,16 @@
 }
 
 body {
-    margin: 0;
-    font-family: var(--font-family);
-    background-color: var(--color-bg);
-    color: var(--color-text-main);
-    transition: background-color 0.3s ease, color 0.3s ease;
-    line-height: 1.5;
+  margin: 0;
+  font-family: var(--font-family);
+  background-color: var(--color-bg);
+  color: var(--color-text-main);
+  transition: background-color 0.3s ease, color 0.3s ease;
+  line-height: 1.5;
 }
 
 #root {
-    height: 100vh;
-    display: flex;
-    flex-direction: column;
-}
+  height: 100vh;
+  display: flex;
+  flex-direction: column;
+}
\ No newline at end of file