Broken nav after information architecture refactor

I'm completely stuck trying to debug this and our conversion rates are tanking because mobile users can't navigate.

It sounds like you're in a classic "just refactored and now everything's broken" scenario, a common rite of passage for anyone working on frontend projects. 'Tanking' conversion rates is certainly a vivid way to describe the pain of a broken user experience.

The Uncaught TypeError: Cannot read properties of null (reading 'style') error points directly to a JavaScript issue where your code is attempting to access the style property of an element that doesn't exist in the DOM at that specific moment, or the reference to it is null. Given it's happening specifically on mobile breakpoints after an information architecture refactor, here’s a structured approach to diagnose and fix it:

1. Verify Element Existence & Selector Accuracy

The most probable cause is that the JavaScript in main.js, specifically around line 123 in your initMobileNav function, is trying to find an element using a selector (e.g., an ID or class) that either:

• Does not exist in the HTML when rendered on mobile.
• Has been changed during your refactor and the JS wasn't updated.
• Is not yet loaded into the DOM when initMobileNav is executed.

Actionable Steps:

1. Inspect Mobile DOM: Open your browser's developer tools, switch to a mobile viewport (e.g., iPhone X), and go to the "Elements" tab. Carefully examine the HTML structure of your mobile navigation. Does the hamburger icon, the menu container, or any other element your initMobileNav function targets actually exist with the correct IDs and classes?
2. Pinpoint the Null Variable: In main.js at line 123, identify which variable is returning null. For example, if you have document.querySelector('.mobile-menu-toggle').style.display = 'none';, then document.querySelector('.mobile-menu-toggle') is likely returning null. Add a console.log() right before line 123 to print the element variable you're trying to access. E.g., const myElement = document.querySelector('.some-selector'); console.log(myElement);

2. Script Execution Timing

Your error trace shows at HTMLDocument.<anonymous> (app.js:45:7), suggesting initMobileNav is being called from app.js, likely within a DOMContentLoaded listener or similar. However, if your scripts are loaded asynchronously or deferred, there's a chance the HTML for the mobile navigation isn't fully parsed yet when initMobileNav runs.

Actionable Steps:

1. Ensure DOM Readiness: Double-check that all your JavaScript that interacts with the DOM is wrapped within a DOMContentLoaded event listener, or that your scripts are placed just before the closing </body> tag. This ensures the HTML structure is fully available before your script tries to manipulate it.
2. Check Script Loading Order: If your mobile navigation HTML is dynamically loaded or inserted, ensure that script runs *after* that dynamic insertion is complete.

3. Responsive Design Logic & CSS Media Queries

A refactor often involves changes to CSS and JavaScript that control responsiveness. It's possible that the element you're targeting for the mobile menu is being hidden by CSS (e.g., display: none;) at certain breakpoints, but your JavaScript is still trying to interact with it, or vice versa.

Actionable Steps:

1. CSS Inspection: Use the "Styles" tab in your developer tools on a mobile viewport. Select the hamburger menu element and its parent containers. Verify that their display and visibility properties are as expected for a mobile menu that should be toggleable. Sometimes, a desktop-specific CSS rule might inadvertently override a mobile one, making the element effectively invisible or non-existent in the JS context.
2. Breakpoint Consistency: Ensure the breakpoints defined in your CSS media queries align perfectly with any JavaScript logic that conditionally initializes or manipulates the navigation based on screen width. Mismatched breakpoints are a common source of responsive navigation bugs.

4. Debugging Dynamic Mobile Navigation Issues

For more complex frontend debugging, especially with dynamic elements:

• Conditional Breakpoints: Set a breakpoint at main.js:123. When the execution pauses, inspect the scope variables. Hover over the variable that's causing the error to see its value (it will likely be null). Then, work backward to see where that variable was assigned.
• Live Editing: In the browser's "Sources" tab, you can temporarily edit your JavaScript. Try adding more console.log() statements or temporarily changing selectors to test assumptions without redeploying.
• Polyfills/Browser Compatibility: While less likely for this specific error, always ensure your JavaScript is compatible with the target mobile browsers.

Focus on confirming the HTML element's presence and its correct selector within the specific mobile environment first. That null error is almost always a sign that JavaScript can't find what it's looking for in the DOM.

Perfect, the element existence part resonates, I'm gonna check the DOM inspection on mobile breakpoints first.