fix: polish UI styling and layout

Improve readability and consistency across buttons, tabs, and radios.

app.py

@@ -193,7 +193,10 @@ body {
 .gradio-container {
     font-family: 'Inter', sans-serif !important;
     background: linear-gradient(180deg, #f8fafc 0%, #eef2ff 100%) !important;
-    max-width: 1200px !important;
+    max-width: 1440px !important;
+    width: 100% !important;
+    margin-left: auto !important;
+    margin-right: auto !important;
     --button-primary-text-color: #ffffff;
     --button-primary-text-color-hover: #ffffff;
     --button-primary-text-color-active: #ffffff;
@@ -271,12 +274,19 @@ fieldset label span {
 }
 
 fieldset label.selected span {
-    color: #ffffff !important;
+    color: var(--text) !important;
 }
 
 fieldset label.selected {
-    background: var(--accent) !important;
-    border-color: var(--accent) !important;
+    background: transparent !important;
+    border-color: transparent !important;
+    box-shadow: none !important;
+}
+
+fieldset label {
+    border: none !important;
+    background: transparent !important;
+    box-shadow: none !important;
 }
 
 /* Inputs & Textareas */
@@ -361,14 +371,21 @@ ul.options, .gr-dropdown-options {
 }
 
 .gr-button-secondary {
-    background: #e2e8f0 !important;
-    border: 1px solid #cbd5e1 !important;
-    color: #0f172a !important;
-    box-shadow: 0 4px 10px rgba(15, 23, 42, 0.08) !important;
+    background: #475569 !important;
+    border: 1px solid #334155 !important;
+    color: #ffffff !important;
+    box-shadow: 0 4px 10px rgba(15, 23, 42, 0.15) !important;
 }
 .gr-button-secondary:hover {
-    background: #dbe3ef !important;
-    border-color: #94a3b8 !important;
+    background: #334155 !important;
+    border-color: #1f2937 !important;
+}
+.gr-button-secondary,
+.gr-button-secondary span,
+.gr-button-secondary p,
+.gr-button-secondary .label {
+    color: #ffffff !important;
+    -webkit-text-fill-color: #ffffff !important;
 }
 
 /* Tabs */
@@ -383,6 +400,12 @@ ul.options, .gr-dropdown-options {
     border-radius: 0 !important;
     padding: 4px 10px !important;
     border-bottom: none !important;
+    box-shadow: none !important;
+}
+.tabs button.selected::after {
+    display: none !important;
+    content: none !important;
+    border-bottom: none !important;
 }
 
 /* Radio buttons */
@@ -390,17 +413,25 @@ ul.options, .gr-dropdown-options {
     color: var(--text) !important;
 }
 
-/* Radio dot visibility (checked) */
+/* Radio: custom filled dot */
 .gr-check-radio input[type="radio"] {
+    appearance: none !important;
+    -webkit-appearance: none !important;
+    -moz-appearance: none !important;
     width: 16px !important;
     height: 16px !important;
-    accent-color: #111827 !important; /* black dot */
+    border-radius: 999px !important;
+    border: 2px solid #cbd5e1 !important;
+    background: transparent !important;
+    display: inline-block !important;
+    position: relative !important;
+    box-sizing: border-box !important;
+    vertical-align: middle !important;
 }
 
 fieldset label.selected input[type="radio"] {
-    accent-color: #111827 !important;
-    background-color: #111827 !important;
-    border: 1px solid #111827 !important;
+    border-color: var(--accent) !important;
+    background: radial-gradient(circle at center, #4f46e5 0 5px, transparent 5px) !important;
 }
 
 /* Footer */
@@ -424,7 +455,7 @@ extra_css = """
 """
 
 with gr.Blocks(title="UltraData-Math L3 Generator", css=custom_css, theme=gr.themes.Soft()) as demo:
-    gr.HTML('<h1 class="main-title">🧮 UltraData-Math L3 Generator</h1>')
+    gr.HTML('<h1 class="main-title">UltraData-Math L3 Generator</h1>')
     gr.HTML('<p class="subtitle">✨ Next-Gen Mathematical Data Synthesis Powered by LLM ✨</p>')
     gr.HTML(extra_css)
     
@@ -451,8 +482,8 @@ with gr.Blocks(title="UltraData-Math L3 Generator", css=custom_css, theme=gr.the
                             qa_btn = gr.Button("Generate", variant="primary")
                     
                     with gr.Column(scale=1):
-                        qa_problem = gr.Textbox(label="Generated Problem", lines=5, show_copy_button=True)
-                        qa_solution = gr.Textbox(label="Generated Solution", lines=12, show_copy_button=True)
+                        qa_problem = gr.Textbox(label="Generated Problem", lines=5)
+                        qa_solution = gr.Textbox(label="Generated Solution", lines=12)
                         qa_raw = gr.Textbox(label="Raw Response", lines=4, visible=False)
             
             qa_example_btn.click(
@@ -487,7 +518,7 @@ with gr.Blocks(title="UltraData-Math L3 Generator", css=custom_css, theme=gr.the
                             conv_btn = gr.Button("Generate", variant="primary")
                     
                     with gr.Column(scale=1):
-                        conv_output = gr.Textbox(label="Generated Conversation", lines=20, show_copy_button=True)
+                        conv_output = gr.Textbox(label="Generated Conversation", lines=20)
                         conv_raw = gr.Textbox(label="Raw Response", lines=4, visible=False)
             
             conv_example_btn.click(
@@ -522,7 +553,7 @@ with gr.Blocks(title="UltraData-Math L3 Generator", css=custom_css, theme=gr.the
                             rewrite_btn = gr.Button("Generate", variant="primary")
                     
                     with gr.Column(scale=1):
-                        rewrite_output = gr.Textbox(label="Rewritten Content", lines=20, show_copy_button=True)
+                        rewrite_output = gr.Textbox(label="Rewritten Content", lines=20)
                         rewrite_raw = gr.Textbox(label="Raw Response", lines=4, visible=False)
             
             rewrite_example_btn.click(
@@ -551,7 +582,7 @@ with gr.Blocks(title="UltraData-Math L3 Generator", css=custom_css, theme=gr.the
                             know_btn = gr.Button("Generate", variant="primary")
                     
                     with gr.Column(scale=1):
-                        know_output = gr.Textbox(label="Extracted Knowledge Points", lines=20, show_copy_button=True)
+                        know_output = gr.Textbox(label="Extracted Knowledge Points", lines=20)
                         know_raw = gr.Textbox(label="Raw Response", lines=4, visible=False)
             
             know_example_btn.click(
@@ -586,7 +617,7 @@ with gr.Blocks(title="UltraData-Math L3 Generator", css=custom_css, theme=gr.the
                             textbook_btn = gr.Button("Generate", variant="primary")
                     
                     with gr.Column(scale=1):
-                        textbook_output = gr.Textbox(label="Generated Exercise Material", lines=20, show_copy_button=True)
+                        textbook_output = gr.Textbox(label="Generated Exercise Material", lines=20)
                         textbook_raw = gr.Textbox(label="Raw Response", lines=4, visible=False)
             
             textbook_example_btn.click(