function calcTT(){var ttdist=parseInt(document.getElementById("ttdist").value)||400;var ttime=document.getElementById("ttime").value||"4:50";var tdist=parseInt(document.getElementById("tdist").value)||400;var p=ttime.split(":");var secs=parseInt(p[0])*60+(parseInt(p[1])||0);var pace100=secs/(ttdist/100);var pred=pace100*(tdist/100);var pm=Math.floor(pred/60),ps=Math.round(pred%60);document.getElementById("r1").textContent=Math.floor(pace100/60)+":"+String(Math.round(pace100%60)).padStart(2,"0");document.getElementById("r2").textContent=pm+":"+String(ps).padStart(2,"0");document.getElementById("desc").innerHTML="From your "+ttdist+"m time trial of "+ttime+":
Pace: "+Math.floor(pace100/60)+":"+String(Math.round(pace100%60)).padStart(2,"0")+"/100m
Predicted "+tdist+"m: "+pm+":"+String(ps).padStart(2,"0")+"
Note: Fatigue factor adds ~1-3% per 400m for longer races.";document.getElementById("results").style.display="block";}