I'm having a hard time understanding how "duration" on tweens and "start/end" values on scroll trigger work together. I want my tween durations to be a percentage of the total scroll distance. If I have this:           var master = gsap.timeline({             scrollTrigger: {                 trigger: ".animation-start",                 start: "top 20%",                 end: "+=2800",                 scrub: true,             },         });   Within master I have