/* =========================================================================
   VANDHE · Rail Solar — design system  (monochrome · editorial · technical)
   Type: Archivo Expanded (display) · Archivo (sub) · IBM Plex Mono (data) · Inter (body)
   No accent chroma — the brushed-steel model is the only colour on the page.
   ========================================================================= */
:root{
  --bg:#0d0e0f; --panel:#141618;
  --ink:#ecebe4; --ink-dim:#c2c1ba; --muted:#83837c; --faint:#54544f;
  --line:rgba(236,235,228,.16); --line-2:rgba(236,235,228,.07); --line-3:rgba(236,235,228,.04);
  --display:"Archivo Expanded","Archivo",Arial,sans-serif;
  --sub:"Archivo",Arial,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,monospace;
  --body:"Inter",system-ui,sans-serif;
  --ease:cubic-bezier(.22,.61,.36,1);
  --pad:clamp(1.15rem,4vw,4rem);
  --maxw:1340px;
}
*{box-sizing:border-box;margin:0;padding:0}
body{background:var(--bg);color:var(--ink);font-family:var(--body);
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;overflow-x:hidden;line-height:1.5}
body.exploring{overflow:hidden}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
::selection{background:var(--ink);color:var(--bg)}

/* ---------- fixed 3D stage ---------- */
#stage{position:fixed;inset:0;z-index:0}
#stage canvas{display:block;width:100%!important;height:100%!important}
#vignette{position:fixed;inset:0;z-index:1;pointer-events:none;
  background:radial-gradient(130% 100% at 50% 45%,transparent 55%,rgba(0,0,0,.42) 100%)}
#grain{position:fixed;inset:-50%;z-index:1;pointer-events:none;opacity:.028;
  background-image:url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2'/></filter><rect width='100%25' height='100%25' filter='url(%23n)'/></svg>")}
#hotspots{position:fixed;inset:0;z-index:3;pointer-events:none}

/* ---------- viewfinder frame + running readout ---------- */
#frame{position:fixed;inset:clamp(.8rem,1.6vw,1.5rem);z-index:4;pointer-events:none}
#frame span{position:absolute;width:16px;height:16px;border:1px solid var(--line)}
#frame .tl{top:0;left:0;border-right:0;border-bottom:0}
#frame .tr{top:0;right:0;border-left:0;border-bottom:0}
#frame .bl{bottom:0;left:0;border-right:0;border-top:0}
#frame .br{bottom:0;right:0;border-left:0;border-top:0}
#readout{position:fixed;left:var(--pad);bottom:clamp(1.1rem,3vh,2rem);z-index:4;pointer-events:none;
  font-family:var(--mono);font-size:.66rem;letter-spacing:.1em;color:var(--faint);
  display:flex;gap:1.4rem;text-transform:uppercase}
#readout b{color:var(--muted);font-weight:400}
@media(max-width:820px){#readout{display:none}}

/* ---------- top progress ---------- */
#progress{position:fixed;top:0;left:0;height:1px;width:100%;z-index:60;background:var(--ink);
  transform:scaleX(0);transform-origin:0 50%;opacity:.6}

/* ---------- header ---------- */
#header{position:fixed;top:0;left:0;right:0;z-index:50;display:flex;align-items:center;
  justify-content:space-between;padding:clamp(1.1rem,2.4vw,1.8rem) var(--pad);
  transition:background .4s,backdrop-filter .4s,padding .4s,border-color .4s;border-bottom:1px solid transparent}
#header.scrolled{background:rgba(13,14,15,.72);backdrop-filter:blur(12px);
  -webkit-backdrop-filter:blur(12px);border-bottom:1px solid var(--line-2);padding-top:.9rem;padding-bottom:.9rem}
.brand{font-family:var(--display);font-weight:800;font-size:1.02rem;letter-spacing:.02em;
  display:flex;align-items:center;gap:.6ch;line-height:1}
.brand i{width:6px;height:6px;background:var(--ink);display:inline-block;transform:translateY(-1px)}
.nav{display:flex;gap:2.4rem;align-items:center}
.nav-links{display:flex;gap:2rem}
.nav a{font-family:var(--mono);font-size:.68rem;letter-spacing:.14em;text-transform:uppercase;
  color:var(--muted);transition:color .3s;position:relative;padding-bottom:.3em}
.nav a::after{content:"";position:absolute;left:0;bottom:0;height:1px;width:0;background:var(--ink);transition:width .35s var(--ease)}
.nav a:hover{color:var(--ink)}.nav a:hover::after{width:100%}
.nav .lead-link{color:var(--ink)}
@media(max-width:900px){.nav-links{display:none}}

/* ---------- links / buttons (understated, hairline) ---------- */
.link{font-family:var(--mono);font-size:.72rem;letter-spacing:.12em;text-transform:uppercase;
  color:var(--ink);display:inline-flex;align-items:center;gap:.7ch;padding-bottom:.35em;
  border-bottom:1px solid var(--line);transition:border-color .3s,gap .3s}
.link:hover{border-color:var(--ink);gap:1.1ch}
.link .arw{transition:transform .3s var(--ease)}.link:hover .arw{transform:translateX(3px)}
.btn{font-family:var(--mono);font-size:.72rem;letter-spacing:.12em;text-transform:uppercase;
  display:inline-flex;align-items:center;gap:.8ch;padding:.95em 1.5em;border:1px solid var(--line);
  color:var(--ink);background:transparent;cursor:pointer;transition:background .3s,color .3s,border-color .3s}
.btn:hover{background:var(--ink);color:var(--bg);border-color:var(--ink)}
.btn .arw{transition:transform .3s var(--ease)}.btn:hover .arw{transform:translateX(3px)}

/* ---------- layout ---------- */
#scroll{position:relative;z-index:2}
.section{min-height:100svh;display:flex;align-items:center;padding:clamp(6rem,13vh,10rem) var(--pad);position:relative}
.wrap{width:100%;max-width:var(--maxw);margin:0 auto;display:grid}
.col{max-width:min(40ch,92vw)}
.col:has(.stats),.col:has(.specs-list){max-width:min(600px,92vw)}
.sec--left .wrap{justify-items:start}
.sec--right .wrap{justify-items:end}
.sec--center .wrap{justify-items:center;text-align:center}
.sec--center .col{max-width:52ch}
/* legibility scrim behind copy */
.section::before{content:"";position:absolute;inset:0;z-index:-1;pointer-events:none}
.sec--left::before{background:linear-gradient(90deg,rgba(13,14,15,.9) 0%,rgba(13,14,15,.45) 36%,transparent 62%)}
.sec--right::before{background:linear-gradient(270deg,rgba(13,14,15,.9) 0%,rgba(13,14,15,.45) 36%,transparent 62%)}
.sec--center::before{background:radial-gradient(90% 75% at 50% 60%,rgba(13,14,15,.82),transparent 78%)}
/* daylight mode: keep copy legible over the bright sky */
body.daylight .sec--left::before{background:linear-gradient(90deg,rgba(11,12,13,.96) 0%,rgba(11,12,13,.74) 40%,transparent 70%)}
body.daylight .sec--right::before{background:linear-gradient(270deg,rgba(11,12,13,.96) 0%,rgba(11,12,13,.74) 40%,transparent 70%)}
body.daylight .sec--center::before{background:radial-gradient(96% 84% at 50% 55%,rgba(11,12,13,.93),rgba(11,12,13,.45) 58%,transparent 82%)}
body.daylight #header:not(.scrolled){background:linear-gradient(180deg,rgba(11,12,13,.65),transparent)}

/* ---------- labels / eyebrow (mono, with section index) ---------- */
.eyebrow{font-family:var(--mono);font-size:.7rem;letter-spacing:.16em;text-transform:uppercase;
  color:var(--muted);display:flex;align-items:center;gap:1ch;margin-bottom:1.6rem}
.eyebrow b{color:var(--ink);font-weight:500}
.eyebrow::before{content:"";width:2.2em;height:1px;background:var(--line)}
.sec--right .eyebrow{flex-direction:row-reverse}

/* ---------- titles (Archivo Expanded, mixed case) ---------- */
.title{font-family:var(--display);font-weight:700;letter-spacing:-.02em;line-height:1.02;
  font-size:clamp(2rem,4.6vw,3.9rem);margin-bottom:1.5rem}
.title em{font-style:normal;text-decoration:underline;text-decoration-thickness:1px;
  text-underline-offset:.14em;text-decoration-color:var(--line)}
.lead{font-size:clamp(1rem,1.2vw,1.12rem);line-height:1.68;color:var(--ink-dim);max-width:42ch}
.sec--right .lead{margin-left:auto}
.lead+.lead{margin-top:1rem}
.lead.dim{color:var(--muted)}
.kicker{font-family:var(--mono);font-size:.68rem;letter-spacing:.1em;text-transform:uppercase;color:var(--faint);margin-top:2rem}
.actions{display:flex;gap:1.6rem;align-items:center;margin-top:2.4rem;flex-wrap:wrap}
.sec--center .actions{justify-content:center}
.sec--right .actions{justify-content:flex-end}

/* ---------- hero ---------- */
#hero{align-items:flex-end;padding-bottom:clamp(4.5rem,10vh,7rem)}
#hero .wrap{grid-template-columns:1fr auto;align-items:end;gap:2rem}
.hero-lead-block{max-width:52ch}
.hero-eyebrow{font-family:var(--mono);font-size:.72rem;letter-spacing:.2em;text-transform:uppercase;
  color:var(--muted);margin-bottom:1.8rem;display:flex;gap:1ch;align-items:center}
.hero-eyebrow::before{content:"";width:2.6em;height:1px;background:var(--line)}
.hero-title{font-family:var(--display);font-weight:800;line-height:.98;letter-spacing:-.028em;
  font-size:clamp(2.5rem,6.6vw,5.9rem);max-width:16ch}
.hero-line{display:block;overflow:hidden}
.hero-line span{display:block}
.hero-title em{font-style:normal;text-decoration:underline;text-decoration-thickness:2px;
  text-underline-offset:.1em;text-decoration-color:var(--line)}
.hero-sub{margin-top:1.9rem;max-width:46ch;font-size:clamp(1rem,1.25vw,1.16rem);line-height:1.66;color:var(--ink-dim)}
.hero-cta{margin-top:2.4rem;display:flex;gap:1.6rem;align-items:center;flex-wrap:wrap}
/* technical figure caption (bottom-right of hero) */
.figcap{font-family:var(--mono);font-size:.66rem;line-height:1.7;letter-spacing:.06em;
  color:var(--faint);text-transform:uppercase;text-align:right;border-right:1px solid var(--line);padding-right:1rem}
.figcap b{color:var(--muted);font-weight:400;display:block}
@media(max-width:900px){#hero .wrap{grid-template-columns:1fr}.figcap{display:none}}
.scroll-cue{position:absolute;left:50%;bottom:1.4rem;transform:translateX(-50%);display:flex;flex-direction:column;
  align-items:center;gap:.6rem;color:var(--faint);font-family:var(--mono);font-size:.6rem;letter-spacing:.24em;text-transform:uppercase}
.scroll-cue i{width:1px;height:40px;background:var(--line-2);position:relative;overflow:hidden}
.scroll-cue i::after{content:"";position:absolute;top:-60%;left:0;width:100%;height:60%;background:var(--muted);animation:cue 2s var(--ease) infinite}
@keyframes cue{0%{top:-60%}70%,100%{top:100%}}

/* ---------- data table (specs) ---------- */
.stats{display:grid;grid-template-columns:1fr 1fr;margin-top:2.2rem;width:min(540px,92vw);
  border-top:1px solid var(--line)}
.stat{padding:1.35rem 0;border-bottom:1px solid var(--line-2)}
.stat:nth-child(odd){padding-right:1.6rem;border-right:1px solid var(--line-2)}
.stat:nth-child(even){padding-left:1.6rem}
.stat .n{font-family:var(--display);font-weight:700;font-size:clamp(1.7rem,3.4vw,2.6rem);line-height:1;letter-spacing:-.02em}
.stat .l{font-family:var(--mono);font-size:.64rem;letter-spacing:.12em;text-transform:uppercase;color:var(--muted);margin-top:.7rem}
.specs-list{margin-top:2rem;width:min(540px,92vw);border-top:1px solid var(--line)}
.specs-list .row{display:flex;justify-content:space-between;gap:2rem;padding:.95rem 0;border-bottom:1px solid var(--line-2)}
.specs-list dt{color:var(--muted);font-family:var(--mono);letter-spacing:.06em;text-transform:uppercase;font-size:.68rem;align-self:center}
.specs-list dd{font-family:var(--mono);font-size:.86rem;color:var(--ink);text-align:right}
.note{margin-top:1.3rem;font-family:var(--mono);font-size:.64rem;letter-spacing:.04em;color:var(--faint);text-transform:uppercase}

/* chips (applications) */
.chips{display:flex;flex-wrap:wrap;gap:.6rem;margin-top:2.2rem;max-width:44ch}
.sec--right .chips{margin-left:auto;justify-content:flex-end}
.chip{font-family:var(--mono);font-size:.68rem;letter-spacing:.08em;text-transform:uppercase;
  padding:.6em 1em;border:1px solid var(--line);color:var(--muted);transition:border-color .3s,color .3s}
.chip:hover{border-color:var(--ink);color:var(--ink)}

/* ---------- hotspots (crosshair markers) ---------- */
.hs{position:absolute;top:0;left:0;pointer-events:none;opacity:0;transition:opacity .4s var(--ease);
  border:0;background:none;font-family:var(--mono)}
.hs.is-on{opacity:1;pointer-events:auto;cursor:pointer}
.hs__mark{display:block;width:16px;height:16px;border:1px solid var(--ink);border-radius:50%;position:relative}
.hs__mark::before,.hs__mark::after{content:"";position:absolute;background:var(--ink)}
.hs__mark::before{left:50%;top:-6px;width:1px;height:6px;transform:translateX(-.5px)}
.hs__mark::after{left:50%;top:16px;width:1px;height:6px;transform:translateX(-.5px)}
.hs__num{position:absolute;left:24px;top:-2px;font-size:.62rem;letter-spacing:.1em;color:var(--muted)}
.hs__card{position:absolute;left:24px;top:16px;width:236px;padding:.95rem 1rem;
  background:rgba(13,14,15,.86);backdrop-filter:blur(10px);border:1px solid var(--line);
  opacity:0;transform:translateY(4px);transition:opacity .3s var(--ease),transform .3s var(--ease);
  pointer-events:none;text-align:left}
.hs:hover .hs__card,.hs.is-open .hs__card{opacity:1;transform:translateY(0)}
.hs__card b{font-family:var(--sub);font-weight:600;font-size:.84rem;letter-spacing:0;display:block;margin-bottom:.4rem;text-transform:none;color:var(--ink)}
.hs__card span{font-family:var(--body);font-size:.8rem;line-height:1.55;color:var(--muted);display:block}

/* ---------- controls (hairline squares) ---------- */
#controls{position:fixed;right:var(--pad);bottom:clamp(1.1rem,3vh,2rem);z-index:40;display:flex;gap:.5rem;align-items:center}
.ctl{font-family:var(--mono);font-size:.64rem;letter-spacing:.1em;text-transform:uppercase;color:var(--muted);
  display:inline-flex;align-items:center;gap:.7ch;padding:.7em .9em;cursor:pointer;
  background:rgba(13,14,15,.6);backdrop-filter:blur(10px);border:1px solid var(--line-2);
  transition:border-color .3s,color .3s}
.ctl:hover{border-color:var(--line);color:var(--ink)}
.ctl svg{width:14px;height:14px;stroke:currentColor;fill:none;stroke-width:1.4}
.ctl[aria-pressed="true"]{border-color:var(--ink);color:var(--ink)}
@media(max-width:820px){#controls{left:var(--pad);justify-content:center;flex-wrap:wrap}.ctl span{display:none}.ctl{padding:.7em}}

/* explore mode */
#exploreHint{position:fixed;left:50%;top:calc(env(safe-area-inset-top) + 88px);transform:translateX(-50%);z-index:41;
  display:none;gap:1.4rem;align-items:center;font-family:var(--mono);font-size:.64rem;letter-spacing:.14em;
  text-transform:uppercase;color:var(--muted);background:rgba(13,14,15,.6);backdrop-filter:blur(10px);
  border:1px solid var(--line-2);padding:.7em 1.2em}
body.exploring #exploreHint{display:flex}
body.exploring #header,body.exploring #scroll,body.exploring .scroll-cue{opacity:0;pointer-events:none;transition:opacity .4s}
#exitExplore{cursor:pointer;color:var(--ink);border-bottom:1px solid var(--line)}

/* ---------- footer ---------- */
footer{position:relative;z-index:2;background:linear-gradient(180deg,transparent,var(--bg) 24%);padding:clamp(4rem,10vh,8rem) var(--pad) 2.4rem}
.foot{max-width:var(--maxw);margin:0 auto;display:grid;grid-template-columns:1.7fr 1fr 1fr;gap:3rem;border-top:1px solid var(--line);padding-top:3rem}
.foot .brand{font-size:1.6rem;margin-bottom:1.1rem}
.foot p{color:var(--muted);font-size:.9rem;line-height:1.7;max-width:34ch}
.foot h4{font-family:var(--mono);font-size:.66rem;letter-spacing:.14em;text-transform:uppercase;color:var(--faint);margin-bottom:1.2rem}
.foot ul{list-style:none;display:grid;gap:.7rem}
.foot ul a{color:var(--muted);font-size:.9rem;transition:color .3s}.foot ul a:hover{color:var(--ink)}
.legal{max-width:var(--maxw);margin:2.6rem auto 0;display:flex;justify-content:space-between;gap:1rem;flex-wrap:wrap;
  color:var(--faint);font-family:var(--mono);font-size:.64rem;letter-spacing:.06em;text-transform:uppercase}
@media(max-width:820px){.foot{grid-template-columns:1fr;gap:2rem}}

/* ---------- loader ---------- */
#loader{position:fixed;inset:0;z-index:100;background:var(--bg);display:flex;flex-direction:column;align-items:center;justify-content:center;gap:1.8rem}
#loader .brand{font-size:clamp(1.3rem,3.4vw,1.9rem)}
.loader-track{width:min(240px,54vw);height:1px;background:var(--line-2);overflow:hidden}
#loaderBar{height:100%;width:100%;transform:scaleX(0);transform-origin:0 50%;background:var(--ink);transition:transform .3s var(--ease)}
.loader-meta{display:flex;gap:1ch;align-items:baseline;font-family:var(--mono);letter-spacing:.16em;text-transform:uppercase;font-size:.66rem;color:var(--muted)}
#loaderPct{color:var(--ink)}
#loaderMsg{color:var(--faint)}

body:not(.ready) #scroll{opacity:0}
#scroll{transition:opacity .6s}

@media (prefers-reduced-motion: reduce){
  *{animation-duration:.001ms!important;animation-iteration-count:1!important;transition-duration:.15s!important}
  .scroll-cue i::after{animation:none}
}
@media(max-width:820px){
  .section{min-height:auto;padding-top:24vh;padding-bottom:14vh}
  #hero{min-height:100svh}
}