Story Viewer

<div class="stage"><div class="phone"><div class="notch"></div><div class="screen" id="screen">
<div class="svsegs"><span class="svseg"><i id="f0"></i></span><span class="svseg"><i id="f1"></i></span><span class="svseg"><i id="f2"></i></span></div>
<div class="svbody"></div>
<div class="svzone left" id="zl"></div><div class="svzone right" id="zr"></div></div><div class="home"></div></div></div>

.stage{position:absolute;inset:0;display:grid;place-items:center;overflow:hidden}
.phone{position:relative;height:90vmin;max-height:640px;aspect-ratio:9/19.5;background:#08080c;
  border-radius:20%/8.6%;box-shadow:0 0 0 2px rgba(255,255,255,.08) inset,0 12px 30px rgba(0,0,0,.35)}
.phone .notch{position:absolute;left:50%;top:0;transform:translateX(-50%);width:38%;height:5.6%;
  background:#08080c;border-radius:0 0 46% 46%;z-index:80}
.phone .screen{position:absolute;top:7.6%;left:3%;right:3%;bottom:3%;border-radius:11%/4.6%;overflow:hidden;
  background:var(--surface);color:var(--fg)}
.phone .home{position:absolute;left:50%;bottom:1.1%;transform:translateX(-50%);width:32%;height:3px;
  border-radius:2px;background:rgba(255,255,255,.45);z-index:80}
.pfx{position:absolute;left:0;top:0;width:16px;height:16px;margin:-8px 0 0 -8px;border-radius:50%;
  background:color-mix(in srgb,var(--accent) 55%,transparent);
  box-shadow:0 0 0 6px color-mix(in srgb,var(--accent) 15%,transparent);pointer-events:none;z-index:999;
  transition:opacity .2s}
.pfx.hold{width:30px;height:30px;margin:-15px 0 0 -15px;
  box-shadow:0 0 0 9px color-mix(in srgb,var(--accent) 20%,transparent);
  transition:width .5s linear,height .5s linear,margin .5s linear,box-shadow .5s linear,opacity .2s}

.svsegs{position:absolute;top:5%;left:4%;right:4%;display:flex;gap:4%;z-index:10}
.svseg{flex:1;height:3px;border-radius:2px;background:rgba(255,255,255,.35);overflow:hidden}
.svseg i{display:block;height:100%;width:0%;background:#fff;border-radius:2px}
.svbody{position:absolute;inset:0;background:linear-gradient(160deg,var(--accent),var(--accent-3))}
.svzone{position:absolute;top:0;bottom:0;width:34%;z-index:5}
.svzone.left{left:0}.svzone.right{right:0}

const pfx=document.createElement('div');pfx.className='pfx';document.body.appendChild(pfx);
const screenEl=document.getElementById('screen');
let pfxAuto=true;
function pfxHide(){pfx.style.opacity='0';}
addEventListener('pointerdown',()=>{pfxAuto=false;pfxHide();},{capture:true});
function pfxAt(fx,fy){
  const r=screenEl.getBoundingClientRect();
  const x=r.left+r.width*fx, y=r.top+r.height*fy;
  pfx.style.transform='translate('+x+'px,'+y+'px)';
  return {x,y};
}
function pfxWalk(x0,y0,x1,y1,ms){
  return new Promise(res=>{
    const start=performance.now();
    function step(now){
      if(!pfxAuto) return res();
      const p=Math.min(1,(now-start)/ms), e=1-Math.pow(1-p,3);
      pfxAt(x0+(x1-x0)*e, y0+(y1-y0)*e);
      if(p<1) requestAnimationFrame(step); else res();
    }
    requestAnimationFrame(step);
  });
}
function pfxWait(ms){
  return new Promise(res=>{
    const start=performance.now();
    function step(now){ if(!pfxAuto) return res(); if(now-start<ms) requestAnimationFrame(step); else res(); }
    requestAnimationFrame(step);
  });
}

const segs=[document.getElementById('f0'),document.getElementById('f1'),document.getElementById('f2')];
const DUR=1900;
let idx=0, elapsed=0;
function reset(i){ segs.forEach((s,j)=>{ s.style.width= j<i?'100%':'0%'; }); }
function go(i){ idx=Math.max(0,Math.min(segs.length-1,i)); elapsed=0; reset(idx); }
document.getElementById('zl').addEventListener('pointerdown',()=>{ pfxAuto=false; pfxHide(); go(idx>0?idx-1:0); });
document.getElementById('zr').addEventListener('pointerdown',()=>{ pfxAuto=false; pfxHide(); go(Math.min(segs.length-1,idx+1)); });
async function autoSeq(){
  go(0);
  let last=performance.now();
  while(pfxAuto){
    const now=performance.now(); elapsed+=now-last; last=now;
    const frac=Math.min(1,elapsed/DUR);
    segs[idx].style.width=(frac*100)+'%';
    if(frac>=1){ if(idx<segs.length-1) go(idx+1); else { await pfxWait(500); go(0); last=performance.now(); } }
    pfxAt(idx%2===0?0.78:0.22, 0.5);
    await new Promise(r=>requestAnimationFrame(r));
  }
}
autoSeq();