diff --git a/app.js b/app.js
new file mode 100644
index 0000000..3f80105
--- /dev/null
+++ b/app.js
@@ -0,0 +1,199 @@
+// dom refs
+const video=document.getElementById("video")
+const play=document.getElementById("play")
+const mute=document.getElementById("mute")
+const seek=document.getElementById("seek")
+const volume=document.getElementById("volume")
+const controls=document.getElementById("controls")
+const player=document.getElementById("player")
+const tapUnmute=document.getElementById("tapUnmute")
+const rotate=document.getElementById("rotate")
+
+// player state
+let hideTimer,resizeTimer,lastSeek=-1
+let controlsVisible=false
+let autoplayStartedMuted=true
+let rotated=false
+
+// device check
+const isMobile=matchMedia("(pointer:coarse)").matches||window.innerWidth<=768
+controls.classList.add(isMobile?"mobile-mode":"desktop-mode")
+
+// ui sync
+const syncPlayState=()=>play.textContent=video.paused?"x":"▶"
+const syncRotateState=()=>rotate.textContent=rotated?"⟲":"⟳"
+
+function syncMuteState(){
+  mute.textContent=video.muted||video.volume===0?"u":"a"
+  volume.value=video.muted?0:video.volume
+}
+
+// controls
+function showControls(){
+  if(!controlsVisible){
+    controls.classList.add("visible")
+    controlsVisible=true
+  }
+  clearTimeout(hideTimer)
+  hideTimer=setTimeout(()=>{
+    controls.classList.remove("visible")
+    controlsVisible=false
+  },isMobile?2200:1700)
+}
+
+// prompt
+const showUnmutePrompt=show=>tapUnmute.classList.toggle("visible",!!show)
+
+// layout
+function applyVideoLayout(){
+  if(rotated){
+    video.style.objectFit="contain"
+    video.style.transform="translateZ(0) rotate(90deg) scale(1.15)"
+    return
+  }
+
+  const landscape=video.videoWidth&&video.videoHeight?video.videoWidth>video.videoHeight:true
+  const portraitScreen=window.innerHeight>window.innerWidth
+
+  video.style.objectFit=isMobile&&landscape&&portraitScreen?"contain":"cover"
+  video.style.transform="translateZ(0) scale(1.01)"
+}
+
+// rotate
+function toggleRotate(){
+  rotated=!rotated
+  syncRotateState()
+  applyVideoLayout()
+  showControls()
+}
+
+// autoplay
+async function startPlayback(){
+  video.volume=1
+  video.muted=true
+
+  try{
+    await video.play()
+  }catch(e){
+    console.error(e)
+  }
+
+  showUnmutePrompt(true)
+  syncPlayState()
+  syncMuteState()
+  syncRotateState()
+}
+
+// audio enable
+function enableSoundAndPlay(){
+  video.muted=false
+  if(video.volume===0)video.volume=1
+  video.play().catch(()=>{})
+  autoplayStartedMuted=false
+  showUnmutePrompt(false)
+  syncMuteState()
+  syncPlayState()
+}
+
+// video events
+video.addEventListener("play",()=>{syncPlayState();showControls()})
+video.addEventListener("pause",()=>{syncPlayState();showControls()})
+video.addEventListener("ended",()=>{syncPlayState();showControls()})
+
+video.addEventListener("loadedmetadata",()=>{
+  applyVideoLayout()
+
+  requestIdleCallback?.(()=>{
+    const t=document.querySelector(".video-text")
+    if(t)t.textContent=""
+  })
+
+  syncMuteState()
+  syncPlayState()
+})
+
+video.addEventListener("timeupdate",()=>{
+  if(!video.duration)return
+  const value=((video.currentTime/video.duration)*100)|0
+  if(value===lastSeek)return
+  lastSeek=value
+  seek.value=value
+})
+
+// controls
+play.addEventListener("click",async e=>{
+  e.stopPropagation()
+  if(video.paused){
+    try{await video.play()}catch{}
+  }else{
+    video.pause()
+  }
+})
+
+mute.addEventListener("click",e=>{
+  e.stopPropagation()
+
+  if(video.muted||video.volume===0){
+    video.muted=false
+    if(video.volume===0)video.volume=.5
+    autoplayStartedMuted=false
+    showUnmutePrompt(false)
+  }else{
+    video.muted=true
+  }
+
+  syncMuteState()
+})
+
+seek.addEventListener("input",e=>{
+  e.stopPropagation()
+  if(video.duration)video.currentTime=(e.target.value/100)*video.duration
+})
+
+volume.addEventListener("input",e=>{
+  e.stopPropagation()
+  video.volume=parseFloat(e.target.value)
+  video.muted=video.volume===0
+
+  if(video.volume>0){
+    autoplayStartedMuted=false
+    showUnmutePrompt(false)
+  }
+
+  syncMuteState()
+})
+
+rotate.addEventListener("click",e=>{
+  e.stopPropagation()
+  toggleRotate()
+})
+
+tapUnmute.addEventListener("click",e=>{
+  e.stopPropagation()
+  enableSoundAndPlay()
+})
+
+controls.addEventListener("click",e=>e.stopPropagation())
+
+player.addEventListener("click",()=>{
+  showControls()
+  if(autoplayStartedMuted&&video.muted)enableSoundAndPlay()
+},{passive:true})
+
+player.addEventListener("mousemove",showControls)
+player.addEventListener("mouseenter",showControls)
+player.addEventListener("touchstart",showControls,{passive:true})
+
+// resize
+window.addEventListener("resize",()=>{
+  clearTimeout(resizeTimer)
+  resizeTimer=setTimeout(applyVideoLayout,100)
+})
+
+window.addEventListener("orientationchange",applyVideoLayout)
+
+// init
+syncPlayState()
+syncMuteState()
+syncRotateState()
+startPlayback()
\ No newline at end of file