app.py

import gradio as gr

def generate(prompt):
    return None

theme = gr.themes.Base(
    primary_hue="gray",
    secondary_hue="gray",
    neutral_hue="gray",
    font=['Helvetica', 'ui-sans-serif', 'system-ui', 'sans-serif'],
).set(
    button_large_text_weight='400',
    input_background_fill='*primary_50',
)

with gr.Blocks(theme=theme) as demo:
    img = gr.Image()
    textbox = gr.Textbox()
    button = gr.Button("generate")
    button.click(fn=generate, inputs=textbox, outputs=img)

demo.launch()