how can i tell gsap and js to do something ONLY IF width is above 1200px?

i’m in trouble with a project. I’m trying to create a horizontal scroll with Javascript and GSAP, but only if width is > 1200px. i did a thing and it kinda works, but if i resize the web page to a smaller width it still does the horizontal scroll. srry for my english and please help me!!!

const aboutContainer = document.querySelector(".about__container");
const aboutContent = gsap.utils.toArray(".about__container .about__content");
const aboutMask = document.querySelector(".about__mask");
if (document.body.clientWidth > 1200) {
  let scrollTween = () => {
    gsap.to(aboutContent, {
      xPercent: -100 * (aboutContent.length - 1),
      ease: "none",
      scrollTrigger: {
        trigger: ".about__container",
        pin: true,
        scrub: 1,
        end: "+=3000",
      },
    });

    gsap.to(aboutMask, {
      width: "100%",
      scrollTrigger: {
        trigger: ".about__section",
        start: "top left",
        scrub: 1,
      },
    });

    let tl = gsap.timeline({
      scrollTrigger: {
        trigger: ".about__container",
        start: "center bottom",
      },
    });

    tl.from(aboutContent, { x: 300, opacity: 0, duration: 1 });
  };
  scrollTween();
};