chore: update guideflow header logo font

Signed-off-by: Suvaditya Mukherjee <suvadityamuk@gmail.com>

demos/run_gradio_demo.py

@@ -344,7 +344,7 @@ h1, h2, h3, span, p {{
     transform: translateY(0.5rem);
 }}
 .title-uide, .title-flow, .title-3d {{
-    font-family: 'Avenir Next Heavy', sans-serif;
+    font-family: 'Avenir Next Regular', 'Inter', 'Roboto', sans-serif;
     font-size: 3.5rem;
     font-weight: normal;
     line-height: 1.2;
@@ -354,15 +354,12 @@ h1, h2, h3, span, p {{
     -webkit-background-clip: text;
     background-clip: text;
     color: transparent;
-    font-family: 'Avenir Next Regular', 'Inter', 'Roboto', sans-serif;
 }}
 .title-flow {{
     color: {GUIDEFLOW_BLUE};
-    font-family: 'Avenir Next Regular', 'Inter', 'Roboto', sans-serif;
 }}
 .title-3d {{
     color: {GUIDEFLOW_YELLOW};
-    font-family: 'Avenir Next Regular', 'Inter', 'Roboto', sans-serif;
 }}
 .subtitle {{
     font-size: 1.5rem;