skills.rest
cathayrisk
cathayriskCOMMUNITY
Explore all skills by this author →
GitHub

customizing-streamlit-theme

Configure Streamlit app themes via .streamlit/config.toml for consistent UI styling.

Updated Apr 20, 2025
Search Tags:#theming#css#customization#ui-design#streamlit#dark-mode#config.toml
One-click install
npx skills add https://github.com/cathayrisk/Anya --skill customizing-streamlit-theme
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: customizing-streamlit-theme
Source: https://github.com/cathayrisk/Anya/tree/main/skills/developing-with-streamlit/skills/customizing-streamlit-theme
Command: npx skills add https://github.com/cathayrisk/Anya --skill customizing-streamlit-theme

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Streamlit apps often look inconsistent or require fragile CSS hacks to match brand colors and UX expectations; this Skill explains how to apply reliable, maintainable theming so apps look consistent across updates and users.

Core Features & Use Cases

  • Configure global colors, fonts, and light/dark bases via the app configuration file to ensure consistent UI across pages and widgets.
  • Define separate light and dark theme variants so users can switch modes without breaking visuals, and detect the active theme at runtime for adaptive logic.
  • Provide guidance to avoid custom CSS, and when necessary, recommend using key-based widget targeting for minimal, targeted overrides.
  • Use Case: Quickly standardize the appearance of internal dashboards and public demos by setting primaryColor, backgroundColor, and fonts in the Streamlit config.

Quick Start

Edit your .streamlit/config.toml to set primaryColor, backgroundColor, secondaryBackgroundColor, and font, then restart the app to see the theme applied.

Frequently Asked Questions about customizing-streamlit-theme

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I customize the theme of a Streamlit app?▼

Streamlit theme customization is done by configuring primaryColor, backgroundColor, secondaryBackgroundColor, and font settings in your .streamlit/config.toml file, then restarting the app to see the consistent UI styling applied.

How does dark mode theming work in Streamlit?▼

Streamlit dark mode theming works by defining separate light and dark theme variants in config.toml. You can detect the active theme at runtime using st.context.theme to trigger adaptive logic without breaking visuals.

What is the best way to style Streamlit widgets without custom CSS?▼

The best way to style Streamlit widgets without custom CSS is configuring global colors and fonts in config.toml. This ensures maintainable theming across pages and widgets, avoiding fragile CSS hacks during updates.

Can I use custom CSS for targeted widget overrides in Streamlit?▼

You can use custom CSS for targeted Streamlit widget overrides only as a last resort. The recommended approach is key-based widget targeting to apply minimal, specific style changes without making the app brittle.

Why does my Streamlit custom CSS break after updates?▼

Streamlit custom CSS breaks after updates because it relies on internal HTML structures that change between versions. Using config.toml for theming instead of CSS hacks ensures reliable, maintainable UI styling across updates.

Related Skills

Explore More Software Engineering Skills→
erickfmmerickfmm

creating-streamlit-themes

Centralize Streamlit theming via a single config.toml.

Community
Intermediate
sanky369sanky369
29

color-system

Create cohesive color systems with accessible theming and dark-mode support.

Community
Advanced
rahul-s-bhattrahul-s-bhatt

improving-streamlit-design

Improves Streamlit application visual design using built-in UI configuration features.

Community
Basic
spencerpaulyspencerpauly
672

converting-css-to-tailwind

Convert plain CSS stylesheets into Tailwind utility classes in markup.

Community
Intermediate