style.css

import gradio as gr

css = """
html, body, #root {
    width: 100% !important;
    height: 100% !important;
    margin: 0 !important;
    padding: 0 !important;
    overflow-x: hidden !important;
    overflow-y: auto !important;
}
* {
    max-width: 100% !important;
    box-sizing: border-box !important;
}
img, svg, canvas, iframe {
    max-width: 100% !important;
    height: auto !important;
}
@media (max-width: 768px) {
    html {
        font-size: 14px !important;
    }
    button, input, select, textarea {
        font-size: 14px !important;
    }
}
"""

with gr.Blocks(css=css) as demo:
    # Your UI here
    pass

demo.launch()