/* Home page: three scroll-led chapters over the steel specimen artwork. */
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}

.steel-story{position:relative;background:var(--steel-1);color:var(--steel-text);border-top:1px solid var(--steel-line)}
.story-sticky{position:relative;max-width:1800px;margin:auto;padding:26px clamp(24px,5vw,90px) 24px}
.story-topline{display:flex;align-items:center;justify-content:space-between;gap:20px;font-size:15px;line-height:1.5;color:var(--steel-dim)}
.story-skip{flex:none;font-size:15px;color:var(--steel-mut);padding:6px 0;border-bottom:1px solid transparent;transition:color .25s,border-color .25s}
.story-skip:hover{color:#fff;border-bottom-color:var(--accent-bright)}
.story-layout{display:grid;grid-template-columns:.86fr 1.14fr;align-items:center;gap:2vw;min-height:600px}
.story-narrative{position:relative;z-index:2;max-width:520px}
.story-chapter{padding-block:40px}
.story-chapter h3{font-size:clamp(34px,3.6vw,54px);font-weight:700;line-height:1.08;letter-spacing:-.01em;color:var(--steel-text)}
.story-chapter p{font-size:17px;line-height:1.75;color:var(--steel-mut);max-width:38ch;margin-top:22px}

.story-visual{position:relative;height:600px;min-width:0;isolation:isolate;pointer-events:none}
.specimen-camera{position:absolute;inset:0;perspective:1600px;perspective-origin:50% 40%;transform-style:preserve-3d}
.specimen{--specimen-size:clamp(240px,30vw,410px);position:absolute;left:50%;top:49%;width:var(--specimen-size);height:var(--specimen-size);transform:translate(-50%,-50%) rotateX(59deg) rotateZ(-32deg);transform-style:preserve-3d}
/* Each plate: one base colour, a shared metallic sheen, a thin machined edge. */
.specimen-layer{
  position:absolute;inset:0;border:1px solid rgba(183,209,248,.6);border-radius:2px;
  background-color:#3b5578;
  background-image:linear-gradient(135deg,rgba(255,255,255,.7),rgba(255,255,255,0) 18%,rgba(255,255,255,.4) 48%,rgba(0,0,0,.35) 85%,rgba(255,255,255,.55));
  box-shadow:inset 0 0 0 2px rgba(207,222,242,.3);
  transform-style:preserve-3d;transform:translateZ(calc((var(--layer) - 1.5)*66px));
}
.specimen-layer::after{content:"";position:absolute;left:-1px;right:-1px;top:100%;height:14px;background:linear-gradient(90deg,rgba(255,255,255,.1),rgba(255,255,255,.55) 30%,rgba(255,255,255,.15) 80%,rgba(0,0,0,.4));background-color:#2b3b50;border:1px solid rgba(140,167,194,.3);transform-origin:top;transform:rotateX(-90deg);border-radius:0 0 2px 2px}
.specimen-layer img{width:100%;height:100%;object-fit:cover;border-radius:2px;opacity:.6;filter:grayscale(1) brightness(1.8);pointer-events:none}
.layer-foundation{--layer:0;background-color:#223956}
.layer-structure{--layer:1;background-color:#142942}
.layer-structure img{filter:grayscale(1) brightness(2.5);opacity:.86}
.layer-transformation{--layer:2;background-color:#4f6f95}
.layer-transformation img{mix-blend-mode:screen;opacity:.85}
.layer-surface{--layer:3;background-color:#5a7a9e}
.layer-surface img{opacity:.42;filter:grayscale(1) contrast(1.4) brightness(1.5)}

.story-progress{position:absolute;bottom:0;left:0;right:0;height:2px;background:rgba(36,54,76,.5)}
.story-progress span{display:block;width:100%;height:100%;background:var(--accent-bright);transform:scaleX(0);transform-origin:left}

.steel-story.motion-ready{height:250svh}
.motion-ready .story-sticky{position:sticky;top:66px;height:calc(100svh - 66px);display:flex;flex-direction:column;overflow:clip}
.motion-ready .story-layout{flex:1;min-height:0}
.motion-ready .story-narrative{height:320px}
.motion-ready .story-chapter{position:absolute;inset:0;padding-block:0;opacity:0;visibility:hidden;transform:translateY(20px);transition:opacity .35s,transform .45s,visibility .35s}
.motion-ready .story-chapter.is-active{opacity:1;visibility:visible;transform:none}
.motion-ready .story-visual{height:100%}
.motion-ready .specimen-camera{will-change:transform}
.steel-story:not(.motion-ready) .story-progress{display:none}

@media (max-width:1100px){
  .story-layout{grid-template-columns:1fr 1.1fr}
  .story-chapter h3{font-size:clamp(32px,4.2vw,46px)}
  .story-chapter p{font-size:16px}
}
@media (max-width:760px){
  .story-topline{flex-wrap:wrap;gap:6px 16px}
  .story-sticky{padding:18px 20px}
  .story-layout{grid-template-columns:1fr;min-height:0}
  .story-chapter{padding-top:30px}
  .story-chapter h3{font-size:clamp(30px,8vw,40px)}
  .story-chapter p{font-size:16px;line-height:1.65;max-width:40ch;margin-top:16px}
  .story-visual{height:440px;grid-row:2}
  .specimen{--specimen-size:clamp(195px,56vw,275px);top:51%;left:50%}
  .specimen-camera{perspective:1100px}
  .steel-story.motion-ready{height:240svh}
  .motion-ready .story-layout{display:flex;flex-direction:column;align-items:stretch;gap:0}
  .motion-ready .story-narrative{height:210px;min-height:210px;margin-top:16px;max-width:none}
  .motion-ready .story-visual{height:auto;flex:1;min-height:170px}
}
@media (max-height:650px){
  .story-layout{min-height:0}
  .story-chapter h3{font-size:36px}
  .story-visual{height:560px}
}
@media (prefers-reduced-motion:reduce){
  .story-chapter{transition:none}
  .story-progress{display:none}
}