I noticed that my header is not staying visible while scrolling the page, the effect on the theme demo is better.
I found a solution here: https://colorlibsupport.com/t/sticky-header-stopped-working/
Adding the CSS code it does not work, can be adapted for Sparkling child too?
Hope you are having a good day and thank you for your question
In order to check your question i need to see your live website, please provide url and i will take a look
Please deactivate all third party plugins and try again your problem, most probably this I conflict with third-party plugins.
Once you deactivate all plugins please check your problem again, if the problem is gone then this means it was a plugin conflict. Now, start activating plugins one by one and same time repeat your problem until your problem appears again, now you know which plugin was in conflict
Colorlib Support Team