Carousel - how to scale Text H1/H2 and Pictures ?

Typo3 3.9.13
Bootstrap Package 11.0.2

How to scale Text & Pictures ?

Normal is the Picture: 2000x400 px works nice with PC/Laptop.
But on Smartphone with resolution: 320x480 can only see a little part of the Picture and only a few characters of the text.

What can I set in the Template:

.carousel .item {
}

.carousel .carousel-item h1 {
}

.carousel .carousel-item h2 {
}

Thanks