diff --git a/rules-new/shopify-theme-dev-liquid.mdc b/rules-new/shopify-theme-dev-liquid.mdc
new file mode 100644
index 00000000..8d89a3d3
--- /dev/null
+++ b/rules-new/shopify-theme-dev-liquid.mdc
@@ -0,0 +1,79 @@
+---
+description: Best practices for Shopify theme development with Liquid, JavaScript, and CSS
+globs:**/*.liquid, assets/*.js, assets/*.css, sections/*.liquid, snippets/*.liquid, templates/**/*.liquid
+---
+
+
+# Shopify Theme Development Best Practices
+
+## Project Structure
+- Adopt a clear **directory structure**, e.g., `sections`, `snippets`, `templates`, `assets`.
+- Organize **generic modules** (like JavaScript functionalities) into separate files.
+- Keep **Liquid files** concise and focused on single responsibilities, avoiding monolithic files.
+- Organize templates and sections by **page or functionality**.
+- Implement proper **internationalization (i18n)** file management.
+- Utilize **SCSS/CSS Modules** for style organization to prevent global pollution.
+
+## Liquid Templating
+- Prefer the `render` tag over `include`.
+- Limit **database queries** within loops to avoid N+1 issues.
+- Use **filters** judiciously, especially complex computational ones.
+- Leverage Liquid's **caching mechanisms** to reduce redundant calculations.
+- Avoid complex **logic handling** directly in Liquid; move intricate logic to JavaScript.
+- Use `assign` and `capture` to define and reuse variables effectively.
+
+## JavaScript Development
+- Modularize JS, using **ES Modules** for imports and exports.
+- Follow modern JavaScript **best practices**, such as `const`/`let`, arrow functions, etc.
+- Avoid direct **DOM manipulation**; prioritize event delegation.
+- Optimize **JavaScript performance** to reduce repaints and reflows.
+- Consider using **Webpack/Rollup** for bundling and code optimization.
+- Write clear **comments** and **JSDoc**.
+
+## CSS/SCSS Styling
+- Adhere to naming conventions like **BEM, OOCSS, or Utility-First CSS**.
+- Optimize **CSS selectors** to improve rendering performance.
+- Use **CSS variables** to manage theme configurations like colors and fonts.
+- Implement **responsive design** to ensure consistent theme appearance across devices.
+- Minimize **CSS file size** by removing unused styles.
+- Make good use of **SCSS mixins** and **functions**.
+
+## Sections and Blocks
+- Utilize Section **Schema** to define configurable options.
+- Maintain **section independence and reusability**.
+- Provide clear **presets** for sections.
+- Use **Blocks** appropriately to enhance section flexibility.
+- Ensure sections provide a good user experience in the **Shopify Customizer**.
+- Avoid hardcoding content within sections; use Schema configurations whenever possible.
+
+## Performance Optimization
+- Optimize **image loading** by using Shopify's CDN and the `image_url` filter.
+- Minify **JavaScript and CSS files**.
+- Leverage **browser caching**.
+- Reduce the number of **HTTP requests**.
+- Consider **lazy loading**.
+- Monitor **theme performance** using Google Lighthouse and Shopify Theme Check.
+
+## Accessibility (A11y)
+- Ensure all interactive elements are **keyboard accessible**.
+- Provide meaningful **`alt` text** for images.
+- Use correct **HTML semantic tags**.
+- Consider **color contrast**.
+- Implement clear **focus states**.
+- Use **ARIA attributes** to enhance the accessibility of complex components.
+
+## Maintenance and Scalability
+- Write clear **code comments** and documentation.
+- Follow **naming conventions** to maintain code consistency.
+- Regularly **test** theme functionalities.
+- Ensure compatibility across different **browsers and devices**.
+- Consider future **extensibility**, avoiding tight coupling.
+- Use **Shopify CLI** for local development and deployment.
+
+## Quality and Testing
+- Use **Shopify Theme Check** for static code analysis.
+- Write **unit tests** (where applicable).
+- Conduct thorough **end-to-end testing**.
+- Test in various environments (local, development store, production store).
+- Focus on **compatibility testing** (browsers, devices, Shopify versions).
+- Test **error handling** and edge cases.
\ No newline at end of file