Checklist

• I have searched the existing issues for similar issues.
• I added a very descriptive title to this issue.
• I have provided sufficient information below to help reproduce this issue.

Summary

When setting one of the values of headingFontSize to "39.5px", the corresponding heading is getting set to 40px. Not a huge thing but it was a bit annoying because I didn't realize whether everything works correctly.

We should probably also check that this works correctly for other font size config options.

Reproducible Code Example

import streamlit as st

st.title("Hello")


# config.toml
[theme]
headingFontSizes = ["39.5px", "32px", "24px"]

Steps To Reproduce

No response

Expected Behavior

The title should be 39.5px

Current Behavior

The title is 40px

Is this a regression?

• Yes, this used to work in a previous version.

Debug info

• Streamlit version: 1.47.0
• Python version:
• Operating System:
• Browser:

Additional Information

No response