easy slider the writings overlap the image

Hey tizianafrison,
Sorry for the late reply, I have taken a look at your site and for the top color section, I used the font size adjustments for mobile devices so the font will be a little smaller and not go off the page. Please see screenshot 1 below.
For the slider below I first added this css to make the caption area a little taller so the text would not be tiny and then I made the caption width 50% so it would not be over the images:

@media only screen and (max-width: 768px) { 
#top.home #av_section_2 > div > .template-page.content {
	padding: 0 !important; 
}
#top.home #es-home .av-slideshow-caption {
	width: 50% !important;
}
#top.home #es-home,#top.home #es-home .avia-slideshow-inner, #top.home #es-home li {
	height: 300px !important; 
}
}

Then I used the same technique as above and changed the font size for mobile “tablets” as an example, that is up to 767px please see screenshot 2 below. If you clear your browser cache and adjust it to about 750px-760px you will see the result, screenshot 3 below.
The easiest way to pick the font sizes is to open two tabs one with the page backend to make adjustments, and one with a mobile preview, screenshot 4 below. Just make an adjustment, save and refresh the preview to see if you like it.

Now, these steps still need to be done for small mobile devices 320px-430px so please try to follow these steps to adjust the font sizes as in screenshot 2 to a way you like it.
Just let us know if you need a hand.

Best regards,
Mike