How to fix z-index issue that does not work despite already having position & higher z-index value?

When dealing with z-index issues in CSS, it can sometimes be tricky to identify the cause of the problem. Here are some steps you can take to troubleshoot and fix z-index issues despite already having the correct position and higher z-index value:

1. Check Element Positioning: Ensure that the elements involved in the z-index stacking context have a positioning other than the default (position: static). Elements with a positioning of relative, absolute, or fixed create a new stacking context and can be properly layered using z-index.

2. Verify Z-Index Values: Double-check the z-index values of the elements involved. Make sure that the element you want to appear on top has a higher z-index value than the other elements.

3. Inspect Parent Elements: Check if any parent elements also have z-index applied. Remember that z-index values are relative to the stacking context of the nearest positioned ancestor. If a parent element has a lower z-index, it might be affecting the stacking order of the child elements.

4. Check for Overlapping Content: If the elements are still not stacking as expected, inspect their bounding boxes to see if there is any content that might be overlapping and causing the z-index to behave unexpectedly. Padding, margins, or other elements can sometimes influence the stacking order.

5. Use z-index with position: fixed: When dealing with elements with position: fixed, you may encounter z-index issues. To ensure that fixed elements behave as expected, make sure that they have a z-index applied and avoid overlapping fixed elements with higher z-index values.

6. Stacking Contexts: Keep in mind that z-index only works within the same stacking context. If an element creates a new stacking context (for example, an element with position: relative or position: absolute), its z-index will only be compared to other elements within the same stacking context.

7. Avoid Negative Z-Index Values: Negative z-index values can sometimes lead to unexpected behavior. Stick to using positive z-index values and ensure that the elements you want to stack on top have higher values than the ones below.

8. Resetting Z-Index: If all else fails, try resetting the z-index of all the elements involved and then reapplying the desired z-index values one by one. Sometimes, z-index values might become tangled up, and starting fresh can help identify the issue.

By following these steps and carefully inspecting your CSS and HTML structure, you should be able to pinpoint the cause of the z-index issue and fix it accordingly. Z-index issues can be subtle, so it's essential to be systematic in your troubleshooting approach.