black stripe on header

You mean the menu navigation bar?

Can you show a screenshot and explain where?

You can see it on the Template :
https://fr.www.ads-software.com/themes/skt-hotel-lite/

where it is written “best templates for hotel business”.

Many thanks,
Corinne

That you can remove via style.css using display none in home_slider CSS.

Or else consider purchasing the pro version which allows for removal by removing the slider text.