kleine style änderungen

math-tutor/frontend/src/styles/theme.css

@@ -84,6 +84,7 @@ body {
   flex-direction: column;
   gap: 16px;
   min-height: 0;
+  max-height: 85vh;
 }
 
 .chat-window {
@@ -188,6 +189,7 @@ body {
   display: flex;
   flex-direction: column;
   gap: 12px;
+  flex: 0 0 320px;
 }
 
 .canvas-header {
@@ -242,7 +244,7 @@ body {
   display: flex;
   flex-direction: column;
   gap: 12px;
-  max-height: 80vh;
+  max-height: 85vh;
   overflow-y: auto;
 }