:root{
  --black:#0a0a0a;
  --white:#ffffff;
  --yellow:#ffd91a;
  --blue:#1457ff;
  --red:#ff5a36;
  --lime:#d5ff18;
  --gray:#ececec;
  --bg:#fff;
  --stretch-x:1;
  --stretch-y:1;
  --ceiling-lift:0px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:76px}
body{margin:0;background:var(--bg);color:var(--black);font-family:Arial,Helvetica,sans-serif;line-height:1.5}
button,input,select{font:inherit}
a{color:inherit}
button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:4px solid var(--blue);outline-offset:4px}
.skip{position:fixed;top:-70px;left:10px;z-index:100;background:var(--yellow);padding:10px 14px;font-weight:900}
.skip:focus{top:10px}
.topbar{position:sticky;top:0;z-index:50;min-height:76px;padding:12px clamp(16px,4vw,56px);display:flex;align-items:center;justify-content:space-between;background:#fff;border-bottom:2px solid var(--black)}
.brand{display:flex;gap:12px;align-items:center;text-decoration:none}
.brandmark{display:grid;place-items:center;width:50px;height:50px;border:2px solid var(--black);background:var(--yellow);font-weight:900;letter-spacing:-.18em;overflow:hidden}
.brand b,.brand small{display:block}
.brand b{font-size:.82rem;letter-spacing:.1em}
.brand small{font-size:.68rem;color:#666}
.topbar nav{display:flex;gap:24px}
.topbar nav a{font-size:.78rem;font-weight:900;text-decoration:none}
.hero{display:grid;grid-template-columns:minmax(0,.88fr) minmax(480px,1.12fr);min-height:calc(100vh - 76px);border-bottom:2px solid var(--black)}
.hero-copy{display:flex;flex-direction:column;justify-content:center;padding:clamp(60px,8vw,120px) clamp(24px,7vw,100px)}
.kicker,.micro{margin:0 0 12px;font-size:.72rem;font-weight:900;letter-spacing:.14em;text-transform:uppercase}
.hero h1{max-width:850px;margin:0;font-size:clamp(4rem,7.5vw,8rem);line-height:.82;letter-spacing:-.075em}
.lede{max-width:690px;margin:28px 0 0;font-size:clamp(1.05rem,1.7vw,1.35rem)}
.actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:30px}
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:48px;padding:11px 17px;border:2px solid var(--black);border-radius:0;font-weight:900;text-decoration:none;cursor:pointer}
.dark{background:var(--black);color:#fff}
.outline{background:#fff;color:var(--black)}
.yellow{background:var(--yellow);color:var(--black)}
.ghost{background:transparent;color:#fff;border-color:#fff}
.full{width:100%}
.privacy{max-width:610px;color:#555;font-size:.78rem}
.hero-art{display:grid;place-items:center;min-height:620px;padding:40px;background:var(--yellow);overflow:hidden}
.frame{position:relative;border:2px solid var(--black);background:#111;box-shadow:18px 18px 0 rgba(0,0,0,.14)}
.hero-visual{width:min(860px,100%);aspect-ratio:1536/1024;overflow:hidden}
.hero-visual img,.scene-image{display:block;width:100%;height:100%;object-fit:cover;transform:scale(1.01)}
.hero-overlay,.sound-overlay{position:absolute;inset:0;width:100%;height:100%;pointer-events:none}
.roomlabel{font-size:18px;font-weight:900;letter-spacing:.12em;text-transform:uppercase;fill:var(--black)}
.roomlabel.light{fill:#fff;text-shadow:0 1px 0 rgba(0,0,0,.45)}
.ray,.sray,.softpath,.scatterpath,.latereflection{fill:none;stroke-linecap:round;stroke-linejoin:round;stroke-dasharray:10 14;animation:dash 4.6s linear infinite}
.sray{stroke:rgba(114,164,255,.9);stroke-width:4}
.softpath{stroke:rgba(255,245,245,.68);stroke-width:3.3}
.scatterpath{stroke:rgba(196,224,255,.88);stroke-width:3}
.latereflection{stroke:rgba(161,185,235,.45);stroke-width:2.5}
.faint{opacity:.4}
.direct{fill:none;stroke:var(--red);stroke-width:5.5;stroke-linecap:round}
.r2{animation-delay:-1s}.r3{animation-delay:-2s}
.stagewave{fill:none;stroke:rgba(255,255,255,.86);stroke-width:2;opacity:0;animation:stagepulse 3s ease-out infinite}
.wd1{animation-delay:-1s}.wd2{animation-delay:-2s}
.steps{display:grid;grid-template-columns:repeat(4,1fr);border-bottom:2px solid var(--black)}
.steps div{display:flex;align-items:center;gap:16px;min-height:88px;padding:18px clamp(16px,3vw,38px);border-right:2px solid var(--black)}
.steps div:last-child{border-right:0}
.steps b{font-size:1.5rem}.steps span{font-weight:800}
.section{padding:100px clamp(18px,5vw,80px)}
.sectionhead{display:grid;grid-template-columns:150px minmax(0,930px);gap:36px;margin-bottom:60px}
.num{margin:0;font-size:clamp(4.8rem,8vw,8.6rem);font-weight:900;line-height:.8;letter-spacing:-.08em}
.sectionhead h2{margin:0;font-size:clamp(3rem,5vw,5.8rem);line-height:.9;letter-spacing:-.055em}
.sectionhead>div>p:last-child{max-width:760px;font-size:1.08rem}
.lab{display:grid;grid-template-columns:320px minmax(0,1fr);border:2px solid var(--black)}
.controls{border-right:2px solid var(--black);background:#f7f7f7}
.control{display:grid;gap:9px;padding:22px;border-bottom:2px solid var(--black)}
.ctitle{display:flex;justify-content:space-between;gap:10px;margin-bottom:6px;font-size:.75rem;font-weight:900;letter-spacing:.08em;text-transform:uppercase}
.control label:not(.check){display:flex;justify-content:space-between;gap:10px;margin-top:8px;font-size:.79rem;font-weight:800}
.control input[type=range]{width:100%}
.control select{width:100%;min-height:42px;padding:8px 10px;border:2px solid var(--black);border-radius:0;background:#fff;font-weight:700}
.check{display:grid;grid-template-columns:20px 1fr;gap:9px;align-items:center;font-size:.84rem;font-weight:700}
.check input{width:18px;height:18px}
.controls>.btn{width:calc(100% - 44px);margin:22px}
.stagebar{display:flex;justify-content:space-between;align-items:center;gap:20px;min-height:74px;padding:15px 20px;border-bottom:2px solid var(--black)}
.stagebar strong{display:block;font-size:1.12rem}
.toggle{display:flex;align-items:center;gap:8px;font-size:.78rem;font-weight:900}
.roomstage{background:#101010;padding:18px}
.scene-wrap{position:relative;overflow:hidden;aspect-ratio:1536/1024;min-height:570px;background:#101010;transform:scaleX(var(--stretch-x)) scaleY(var(--stretch-y))}
.scene-wrap .scene-image{filter:saturate(1.02) contrast(1.02) brightness(1.02)}
.surface{position:absolute;pointer-events:none;mix-blend-mode:multiply;opacity:.24;transition:background .22s ease,opacity .22s ease}
.surface.ceiling{left:7%;top:5%;width:87%;height:17%;clip-path:polygon(6% 82%,47% 0,100% 7%,92% 100%,3% 100%)}
.surface.leftwall{left:4%;top:15%;width:25%;height:62%;clip-path:polygon(22% 0,100% 0,100% 82%,5% 77%,0 11%)}
.surface.backwall{left:29%;top:14%;width:56%;height:55%;clip-path:polygon(0 0,95% 1%,95% 100%,0 100%)}
.surface.floor{left:6%;top:60%;width:87%;height:28%;clip-path:polygon(12% 0,88% 0,100% 78%,17% 95%,0 55%)}
.surface[data-material="painted"]{background:rgba(255,255,255,.02)}
.surface[data-material="concrete"]{background:linear-gradient(180deg,rgba(126,126,126,.42),rgba(168,168,168,.3)),radial-gradient(circle at 10% 20%,rgba(255,255,255,.18),transparent 18%),radial-gradient(circle at 70% 40%,rgba(0,0,0,.08),transparent 12%),repeating-linear-gradient(45deg,rgba(255,255,255,.02) 0 8px,rgba(0,0,0,.04) 8px 16px)}
.surface[data-material="brick"]{background:repeating-linear-gradient(0deg,rgba(128,58,40,.28) 0 26px,rgba(255,255,255,.18) 26px 28px),repeating-linear-gradient(90deg,rgba(176,92,62,.42) 0 58px,rgba(255,255,255,.16) 58px 60px)}
.surface[data-material="wood"]{background:repeating-linear-gradient(90deg,rgba(124,84,40,.46) 0 12px,rgba(210,170,110,.14) 12px 14px)}
.surface[data-material="acoustic"]{background:repeating-linear-gradient(0deg,rgba(128,163,143,.34) 0 30px,rgba(255,255,255,.16) 30px 32px),repeating-linear-gradient(90deg,rgba(128,163,143,.18) 0 42px,rgba(255,255,255,.16) 42px 44px)}
.surface[data-material="woodfloor"]{background:repeating-linear-gradient(105deg,rgba(160,118,64,.25) 0 28px,rgba(255,255,255,.16) 28px 31px)}
.surface[data-material="tile"]{background:repeating-linear-gradient(0deg,rgba(193,210,220,.42) 0 50px,rgba(255,255,255,.2) 50px 52px),repeating-linear-gradient(90deg,rgba(193,210,220,.18) 0 50px,rgba(255,255,255,.18) 50px 52px)}
.surface[data-material="concretefloor"]{background:linear-gradient(180deg,rgba(130,130,130,.35),rgba(190,190,190,.18)),repeating-linear-gradient(35deg,rgba(255,255,255,.04) 0 12px,rgba(0,0,0,.05) 12px 24px)}
.surface[data-material="carpet"]{background:radial-gradient(circle at 20% 30%,rgba(255,255,255,.16),transparent 16%),radial-gradient(circle at 70% 70%,rgba(0,0,0,.06),transparent 14%),repeating-linear-gradient(0deg,rgba(132,124,154,.36) 0 14px,rgba(255,255,255,.1) 14px 17px)}
.feature{position:absolute;border:2px solid rgba(255,255,255,.62);box-shadow:0 0 0 1px rgba(0,0,0,.2) inset;background:rgba(255,255,255,.02);backdrop-filter:blur(1px);transition:opacity .2s ease,background .2s ease,border-color .2s ease;pointer-events:none}
.feature span{position:absolute;left:10px;top:10px;padding:4px 8px;background:rgba(10,10,10,.78);color:#fff;font-size:.66rem;font-weight:900;letter-spacing:.08em;text-transform:uppercase}
.feature::after{content:"";position:absolute;inset:0;background:transparent;transition:background .2s ease,opacity .2s ease}
.feature.inactive{border-color:rgba(255,255,255,.28);opacity:.88}
.feature.inactive::after{background:repeating-linear-gradient(135deg,rgba(0,0,0,.45) 0 8px,rgba(255,255,255,.03) 8px 16px)}
.feature.active{box-shadow:0 0 0 2px rgba(213,255,24,.35) inset,0 0 0 1px rgba(0,0,0,.25) inset}
.feature.rug{left:22%;top:70%;width:54%;height:17%;border-radius:44%}
.feature.sofa{left:26%;top:50%;width:44%;height:22%}
.feature.curtains{left:68%;top:18%;width:18%;height:48%}
.feature.books{left:47%;top:16%;width:12.5%;height:30%}
.feature.people{left:14%;top:26%;width:62%;height:56%}
.marker{position:absolute;display:grid;place-items:center;width:18px;height:18px;border-radius:50%;background:var(--lime);box-shadow:0 0 0 3px rgba(10,10,10,.8);z-index:4}
.marker span{position:absolute;top:-36px;left:50%;transform:translateX(-50%);padding:5px 8px;background:rgba(10,10,10,.82);color:#fff;font-size:.66rem;font-weight:900;letter-spacing:.08em;text-transform:uppercase;white-space:nowrap}
.marker-source{left:16%;top:39%}
.marker-listener{left:74.8%;top:38.3%}
.scene-note{position:absolute;right:14px;bottom:14px;padding:8px 10px;background:rgba(10,10,10,.78);color:#ddd;font-size:.72rem;font-weight:700;z-index:3}
.sound-overlay{z-index:2}
.hidden{display:none!important}
.readout{display:grid;grid-template-columns:250px minmax(0,1fr) 330px;background:var(--black);color:#fff;border-top:2px solid var(--black)}
.primary,.meter,.secondary{min-height:132px;padding:20px}.primary{border-right:1px solid #444}
.primary span,.secondary span{display:block;color:#aaa;font-size:.68rem;font-weight:900;letter-spacing:.1em;text-transform:uppercase}
.primary strong{display:block;font-size:3.6rem;line-height:.9}.primary em{display:block;margin-top:10px;color:var(--yellow);font-size:.78rem;font-style:normal;font-weight:800}
.meter{display:grid;grid-template-columns:40px 1fr 40px;gap:12px;align-items:center}.meter>span{font-size:.66rem;font-weight:900}
.track{position:relative;height:14px;background:#2d2d2d}.track i{position:absolute;inset:0 auto 0 0;width:45%;background:var(--yellow)}.track b{position:absolute;top:-7px;left:45%;width:3px;height:28px;background:#fff}
.secondary{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;border-left:1px solid #444}.secondary b{display:block;margin-top:9px}
.listen{display:grid;grid-template-columns:1fr 420px;gap:40px;margin-top:24px;padding:34px;border:2px solid var(--black);background:var(--yellow)}
.listen h3{margin:0;font-size:clamp(2.2rem,4vw,4.2rem);line-height:.92;letter-spacing:-.04em}
.warning{padding-top:12px;border-top:2px solid var(--black);font-weight:800}.listenbox{display:grid;align-content:center;gap:16px;padding:20px;border:2px solid var(--black);background:#fff}.listenbox label{display:flex;justify-content:space-between;font-size:.78rem;font-weight:900}.listenbox input{width:100%}.status{margin:0;font-size:.78rem;font-weight:700}
.test{background:var(--black);color:#fff}.darkhead{color:#fff}.testgrid{display:grid;grid-template-columns:.7fr 1.3fr;gap:22px}
.instructions,.console{border:2px solid #fff}.instruction{display:grid;grid-template-columns:65px 1fr;gap:18px;padding:24px;border-bottom:1px solid #555}.instruction>span{display:grid;place-items:center;width:48px;height:48px;border:2px solid #fff;border-radius:50%;font-weight:900}.instruction p{margin:6px 0 0;color:#bbb;font-size:.88rem}
.privatecard{margin:22px;padding:22px;background:var(--yellow);color:var(--black)}.privatecard p{margin-bottom:0}.console{padding:24px}
.display{position:relative;min-height:440px;padding:26px;margin-bottom:16px;border:2px solid #555;background:#111}.display>strong{display:block;max-width:650px;margin-top:18px;font-size:clamp(2.6rem,5vw,5rem);line-height:.9}.display>p{max-width:650px;color:#aaa}
.countdown{position:absolute;z-index:4;inset:0;display:grid;place-items:center;pointer-events:none;font-size:min(28vw,13rem);font-weight:900;color:var(--yellow)}
#clapCanvas{display:block;width:100%;height:150px;margin-top:28px;border-top:1px solid #444;border-bottom:1px solid #444}
.result{display:grid;grid-template-columns:280px minmax(0,1fr) 350px;margin-top:22px;border:2px solid #fff}.resultmain,.resultexplain,.resultactions{padding:24px}.resultmain{background:var(--yellow);color:var(--black)}.resultmain span{display:block;font-size:.68rem;font-weight:900;letter-spacing:.1em;text-transform:uppercase}.resultmain strong{display:block;font-size:4.4rem;line-height:.9}.resultmain em{display:block;margin-top:10px;font-style:normal;font-weight:900}.resultexplain{border-left:2px solid #fff;border-right:2px solid #fff}.quality{display:flex;justify-content:space-between;gap:20px;padding-top:18px;border-top:1px solid #555}.resultactions{display:flex;flex-wrap:wrap;align-content:start;gap:8px}.resultactions>b{width:100%}.resultactions button{padding:8px 10px;border:1px solid #fff;background:transparent;color:#fff;font-size:.75rem;font-weight:800;cursor:pointer}.resultactions a{width:100%;margin-top:10px;color:var(--yellow);font-weight:900}
.concepts{display:grid;grid-template-columns:repeat(3,1fr);border:2px solid var(--black)}
.concepts article{min-height:440px;padding:26px;border-right:2px solid var(--black);opacity:0;transform:translateY(18px);transition:opacity .7s ease,transform .7s ease,background .3s ease}
.concepts.in article{opacity:1;transform:none}
.concepts.in article:nth-child(2){transition-delay:.14s}
.concepts.in article:nth-child(3){transition-delay:.28s}
.concepts article:last-child{border-right:0}
.concepts article:hover{background:#fafafa}
.concepts article>span{display:grid;place-items:center;width:42px;height:42px;border:2px solid var(--black);border-radius:50%;font-weight:900;transition:background .3s ease,transform .3s ease}
.concepts article:hover>span{background:var(--yellow);transform:rotate(-8deg) scale(1.08)}
.concept{position:relative;height:180px;margin:26px 0;border:2px solid var(--black);overflow:hidden;background:linear-gradient(180deg,#ffffff,#f4f4f0);transition:box-shadow .3s ease,transform .3s ease}
.concept:hover{transform:translateY(-3px);box-shadow:0 10px 0 rgba(10,10,10,.12)}
.concept svg{display:block;width:100%;height:100%}
.concept .cin{stroke-dasharray:9 9;animation:rayslide 1.15s linear infinite}
.concept .cout{stroke-dasharray:7 9;animation:rayslide .95s linear infinite}
.concept .c1{animation-delay:0s}
.concept .c2{animation-delay:-.28s}
.concept .c3{animation-delay:-.56s}
.concept .c4{animation-delay:-.42s}
.concept .c5{animation-delay:-.7s}
.concept .src{animation:srcpulse 2.4s ease-in-out infinite}
.concept .waves circle{transform-box:view-box;transform-origin:30px 90px;animation:wavepulse 2.4s ease-out infinite}
.concept .waves circle:nth-child(2){animation-delay:-.8s}
.concept .waves circle:nth-child(3){animation-delay:-1.6s}
.concept .wallshine{animation:wallshine 3.2s ease-in-out infinite}
.hard .cout{animation-direction:reverse}
.soft .cout{opacity:.28}
.soft .sink{transform-box:fill-box;transform-origin:center;animation:sinkdot 1.8s ease-in-out infinite}
.soft .s2{animation-delay:-.35s}.soft .s3{animation-delay:-.7s}.soft .s4{animation-delay:-1.05s}.soft .s5{animation-delay:-1.4s}
.scatter .blocks rect{animation:blockglow 3.4s ease-in-out infinite}
.scatter .blocks rect:nth-child(2){animation-delay:-1.1s}
.scatter .blocks rect:nth-child(3){animation-delay:-2.2s}
.scatter .cout{stroke-dasharray:5 8;opacity:.85}
@keyframes rayslide{to{stroke-dashoffset:-36}}
@keyframes srcpulse{0%,100%{r:12}50%{r:14}}
@keyframes wavepulse{0%{transform:scale(.6);opacity:.9}70%{opacity:.35}100%{transform:scale(2.3);opacity:0}}
@keyframes wallshine{0%,100%{opacity:.25}50%{opacity:.75}}
@keyframes sinkdot{0%,100%{transform:scale(1);opacity:1}50%{transform:scale(1.8);opacity:.35}}
@keyframes blockglow{0%,100%{fill:#0a0a0a}50%{fill:#3d3d3d}}
.concepts h3{margin:0 0 10px;font-size:2rem;line-height:1}.concepts p{margin:0}
.formula{display:grid;grid-template-columns:1fr 1fr;margin-top:22px;border:2px solid var(--black)}.formula>div{padding:28px}.formula>div:first-child{border-right:2px solid var(--black)}.formula h3{margin:0;font-size:2rem}.equation{display:grid;place-content:center;background:var(--yellow)}.equation b{font-size:clamp(2rem,4vw,4rem);line-height:.95}.equation span{margin-top:10px;font-size:.78rem;font-weight:800}
.disclaimer{display:grid;grid-template-columns:260px 1fr;gap:24px;margin-top:22px;padding:24px;border:2px solid var(--black)}.disclaimer p{margin:0}
footer{padding:28px;background:var(--black);color:#fff;text-align:center;font-weight:900}
@keyframes dash{to{stroke-dashoffset:-52}}
@keyframes stagepulse{0%{transform:scale(.5);opacity:.5}100%{transform:scale(1.5);opacity:0}}
@media(max-width:1100px){
  .hero{grid-template-columns:1fr}
  .hero-art{min-height:520px}
  .lab{grid-template-columns:280px 1fr}
  .readout{grid-template-columns:220px 1fr}
  .secondary{grid-column:1/-1;border-top:1px solid #444;border-left:0}
  .listen{grid-template-columns:1fr}
  .result{grid-template-columns:230px 1fr}
  .resultactions{grid-column:1/-1;border-top:2px solid #fff}
}
@media(max-width:860px){
  .topbar nav{display:none}
  .steps{grid-template-columns:repeat(2,1fr)}
  .sectionhead{grid-template-columns:1fr;gap:18px}
  .num{font-size:4.5rem}
  .lab{grid-template-columns:1fr}
  .controls{border-right:0;border-bottom:2px solid var(--black)}
  .testgrid{grid-template-columns:1fr}
  .concepts{grid-template-columns:1fr}
  .concepts article{border-right:0;border-bottom:2px solid var(--black)}
  .concepts article:last-child{border-bottom:0}
  .formula{grid-template-columns:1fr}
  .formula>div:first-child{border-right:0;border-bottom:2px solid var(--black)}
  .disclaimer{grid-template-columns:1fr}
}
@media(max-width:620px){
  .hero-copy{padding:70px 18px 50px}
  .hero h1{font-size:clamp(4rem,18vw,6rem)}
  .hero-art{min-height:410px;padding:10px}
  .section{padding:72px 14px}
  .steps{grid-template-columns:1fr}
  .steps div{border-right:0;border-bottom:2px solid var(--black)}
  .stagebar{align-items:flex-start;flex-direction:column}
  .scene-wrap{min-height:390px}
  .readout{grid-template-columns:1fr}
  .primary{border-right:0;border-bottom:1px solid #444}
  .secondary{grid-template-columns:1fr}
  .listen{padding:18px}
  .console{padding:12px}
  .display{min-height:420px;padding:18px}
  .result{grid-template-columns:1fr}
  .resultexplain{border-top:2px solid #fff;border-right:0;border-left:0}
  .scene-note{font-size:.65rem;left:10px;right:auto;bottom:10px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*:before,*:after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
}