style: finales CSS-Finishing, inline styles zu CSS-Klassen

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

js/harmonien.js

@@ -27,7 +27,7 @@ function renderHarmony(label, colors, onSaveFavorit, onSaveSchema) {
     hexLabel.textContent = hex;
 
     const btnRow = document.createElement('div');
-    btnRow.style.cssText = 'display:flex;gap:0.25rem';
+    btnRow.className = 'harmony-btn-row';
 
     const favBtn = document.createElement('button');
     favBtn.className = 'action-btn';