Help me with the mobile plataform show up

Hi! I'd like to pre set different size of height for the featured slider. I setted this css code for website and it works fine on computer, but in mobile it gets all ugly, doesn't fit. .site { width: 100%; } #feature-slider .cycle-slideshow { max-width: 100%; } #feature-slider .cycle-slideshow img { width: 1350px; height: 600px } I'd like to set up for both be fine, desktop and mobile view. I'd like to set for mobile the max height to be 300 px. How can I do that? Is that a way to put this demand in different codes? I didn't let the height to be automatic because I have pictures with differents sizes, and pre-setting the slider would be the perfect for me. thank you very much! I'll wait for the answer! the website: cafecomdireito.com