/* 炉冷庵 ROREIAN — shared styles */
:root{
  --sumi:#0f0c0a;      /* ground */
  --kiln:#1a1411;      /* raised surface */
  --line:#2c231c;      /* hairlines */
  --ember:#e2672c;     /* heater glow, primary action */
  --ember-soft:#f2b48f;
  --gold:#c9a46a;      /* brand mark */
  --washi:#ede5d8;     /* text */
  --ash:#a59581;       /* muted text */
  --mincho:'Shippori Mincho B1','Hiragino Mincho ProN','Yu Mincho',serif;
  --gothic:'Zen Kaku Gothic New','Hiragino Sans','Yu Gothic',sans-serif;
  --latin:'Cormorant Garamond','Times New Roman',serif;
  --wrap:1200px;
  --gutter:clamp(20px,5vw,64px);
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:88px}
body{margin:0;background:var(--sumi);color:var(--washi);font-family:var(--gothic);font-size:16px;line-height:1.95;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
img{max-width:100%;height:auto;display:block}
a{color:var(--ember-soft)}
a:hover{color:#fff}
:focus-visible{outline:2px solid var(--ember);outline-offset:3px}
h1,h2,h3{text-wrap:balance;font-family:var(--mincho);font-weight:700;letter-spacing:.06em;line-height:1.45;margin:0}
p{margin:0}
.wrap{max-width:var(--wrap);margin:0 auto;padding:0 var(--gutter)}
.skip{position:absolute;left:-999px;top:0;background:var(--ember);color:#1a0f08;padding:8px 16px;z-index:100}
.skip:focus{left:8px}

/* header */
.site-header{position:sticky;top:0;z-index:50;background:rgba(15,12,10,.92);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;height:76px;max-width:1440px}
.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--washi)}
.logo-tile{display:inline-flex;align-items:center;justify-content:center;background:#efe7da;border-radius:50%;width:56px;height:56px}
.logo-tile img{height:44px;width:auto}
.logo-tile.lg{width:112px;height:112px}
.logo-tile.lg img{height:86px}
.brand b{font-family:var(--mincho);font-size:22px;letter-spacing:.32em;font-weight:700}
.brand small{display:block;font-family:var(--latin);font-size:11px;letter-spacing:.4em;color:var(--ash);line-height:1}
.nav{display:flex;align-items:center;gap:32px}
.nav ul{display:flex;gap:28px;list-style:none;margin:0;padding:0}
.nav ul a{color:#d9cfbf;text-decoration:none;font-size:14px;letter-spacing:.08em}
.nav ul a:hover,.nav ul a[aria-current=page]{color:var(--ember-soft)}
.nav ul a[aria-current=page]{border-bottom:1px solid var(--ember)}
.menu-btn{display:none;background:none;border:1px solid var(--line);color:var(--washi);height:44px;padding:0 16px;font:inherit;font-size:14px;cursor:pointer}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:52px;padding:0 30px;text-decoration:none;font-size:15px;letter-spacing:.12em;border:1px solid transparent;cursor:pointer;font-family:var(--gothic)}
.btn-fire{background:var(--ember);color:#1a0f08;font-weight:700}
.btn-fire:hover{background:#f07a40;color:#1a0f08}
.btn-line{border-color:#5a4a3b;color:var(--washi);background:transparent}
.btn-line:hover{border-color:var(--ember);color:var(--ember-soft)}
.btn-sm{min-height:44px;padding:0 20px;font-size:14px}

/* type helpers */
.kicker{font-size:13px;letter-spacing:.24em;color:var(--gold);margin-bottom:18px;display:block}
.lead{font-family:var(--mincho);font-size:clamp(18px,2vw,22px);line-height:2;letter-spacing:.05em}
.muted{color:var(--ash)}
.note{font-size:12px;color:#7d6e5c;letter-spacing:.06em}
.tbd{display:inline-block;font-size:11px;letter-spacing:.1em;border:1px solid #b0503a;color:#f0a08a;padding:1px 8px;vertical-align:middle;font-family:var(--gothic);font-weight:400}
.num{font-family:var(--latin);font-weight:600;letter-spacing:0}

/* sections */
.section{padding:clamp(80px,10vw,140px) 0}
.section.raised{background:var(--kiln);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.section-head{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:48px;align-items:end;margin-bottom:64px}
.section-head h2{font-size:clamp(30px,4vw,50px)}
.section-head p{color:#cfc4b3;max-width:34em}

/* hero (top page) */
.hero{position:relative;min-height:min(92vh,900px);overflow:hidden;display:flex;align-items:flex-end}
.hero-img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;object-position:center 100%}
.hero::after{content:"";position:absolute;inset:0;background:linear-gradient(90deg,rgba(15,12,10,.85) 0%,rgba(15,12,10,.3) 42%,rgba(15,12,10,0) 72%),linear-gradient(0deg,rgba(15,12,10,.45) 0%,rgba(15,12,10,0) 20%)}
.hero .wrap{position:relative;z-index:2;width:100%;max-width:1440px;display:grid;grid-template-columns:minmax(0,1fr) auto;gap:40px;align-items:end;padding-bottom:72px}
.hero h1{writing-mode:vertical-rl;font-size:clamp(52px,7vw,96px);font-weight:800;letter-spacing:.16em;line-height:1.3;color:#fbf4e8;text-shadow:0 2px 40px rgba(0,0,0,.8);grid-column:2;grid-row:1 / span 2;align-self:start;margin-top:-56px}
.hero-copy{grid-column:1;display:flex;flex-direction:column;gap:32px;max-width:640px}
.hero-actions{display:flex;flex-wrap:wrap;gap:14px}
.hero-facts{grid-column:1;display:flex;flex-wrap:wrap;gap:44px;border-top:1px solid rgba(237,229,216,.18);padding-top:24px;font-size:13px;color:var(--ash)}
.hero-facts strong{display:block;font-family:var(--latin);font-size:34px;color:var(--washi);font-weight:600;line-height:1.2}
.hero-facts strong.jp{font-family:var(--mincho);font-size:28px;letter-spacing:.06em}


/* page hero (inner pages) */
.page-hero{position:relative;min-height:520px;display:flex;align-items:flex-end;overflow:hidden;border-bottom:1px solid var(--line)}
.page-hero img,.page-hero video{position:absolute;inset:0;width:100%;height:100%;object-fit:cover}
.page-hero::after{content:"";position:absolute;inset:0;background:linear-gradient(0deg,rgba(15,12,10,.96) 8%,rgba(15,12,10,.35) 60%,rgba(15,12,10,.2))}
.page-hero .wrap{position:relative;z-index:2;width:100%;padding-bottom:56px}
.page-hero h1{font-size:clamp(34px,5vw,60px)}
.page-hero p{margin-top:18px;max-width:40em;color:#d9cfbf}
.crumb{font-size:12px;color:var(--ash);margin-bottom:14px;display:block}
.crumb a{color:var(--ash)}

/* products grid */
.plate{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:20px}
.item{background:var(--sumi);border:1px solid var(--line);padding:24px;display:flex;flex-direction:column;gap:14px}
.item figure{margin:0;height:260px;background:#1c1612;display:flex;align-items:center;justify-content:center;overflow:hidden}
.item figure img{max-height:250px;width:auto}
.item figure img.cover{width:100%;height:100%;max-height:none;object-fit:cover}
.item .en{font-family:var(--latin);font-size:13px;letter-spacing:.2em;color:var(--ash)}
.item h3{font-size:24px}
.item p{font-size:14px;color:#bfb3a1;line-height:1.9}
.ph{border:1px dashed #4a3d31;color:#8a7a66;font-size:13px;text-align:center;line-height:1.8;padding:12px}

/* band */
.band{position:relative;height:clamp(320px,38vw,460px);overflow:hidden}
.band img,.band video{width:100%;height:100%;object-fit:cover;display:block}
.band .over{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:16px;background:rgba(15,12,10,.55);text-align:center;padding:0 var(--gutter)}
.band .over p{font-family:var(--mincho);font-weight:700;font-size:clamp(28px,4vw,50px);letter-spacing:.12em;color:#fff6ea;text-shadow:0 2px 30px #000}

/* split */
.split{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr);gap:clamp(32px,5vw,72px);align-items:center}
.split.rev{grid-template-columns:minmax(0,1fr) minmax(0,1.25fr)}
.split figure{margin:0}
.split figcaption{margin-top:10px}
.split h2{font-size:clamp(30px,3.6vw,46px);margin-bottom:24px}
.split p+p{margin-top:16px}
.tags{display:flex;flex-wrap:wrap;gap:10px;margin-top:24px;font-size:13px}
.tags span{border:1px solid #3a2f25;padding:6px 14px;color:#d9cfbf}

/* models */
.models{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px;margin-top:56px}
.model{border:1px solid #3a2f25;padding:30px;display:flex;flex-direction:column;gap:12px}
.model.main{border-color:var(--ember);background:#1c130d}
.model h3{font-family:var(--latin);font-size:32px;font-weight:600;letter-spacing:.03em}
.model .price{font-family:var(--latin);font-size:40px;line-height:1.1}
.model .price small{font-family:var(--gothic);font-size:12px;color:var(--ash)}
.model .badge{align-self:flex-start;font-size:12px;background:var(--ember);color:#1a0f08;font-weight:700;padding:2px 10px;letter-spacing:.1em}

/* points */
.points{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:40px}
.point{border-top:1px solid var(--ember);padding-top:24px}
.point h3{font-size:22px;margin-bottom:12px}
.point p{font-size:15px;color:#cfc4b3}

/* simulator */
.sim{display:grid;grid-template-columns:minmax(0,.8fr) minmax(0,1.2fr);gap:clamp(32px,5vw,72px)}
.sim-box{background:var(--kiln);border:1px solid var(--line);padding:clamp(24px,4vw,44px);display:flex;flex-direction:column;gap:30px}
.range label{display:flex;justify-content:space-between;align-items:baseline;font-size:15px;margin-bottom:10px}
.range output{font-family:var(--latin);font-size:26px}
input[type=range]{-webkit-appearance:none;appearance:none;width:100%;height:28px;background:transparent;cursor:pointer}
input[type=range]::-webkit-slider-runnable-track{height:2px;background:#4a3d31}
input[type=range]::-moz-range-track{height:2px;background:#4a3d31}
input[type=range]::-webkit-slider-thumb{-webkit-appearance:none;width:22px;height:22px;border-radius:50%;background:var(--ember);margin-top:-10px;border:3px solid var(--sumi);box-shadow:0 0 0 1px var(--ember)}
input[type=range]::-moz-range-thumb{width:16px;height:16px;border-radius:50%;background:var(--ember);border:3px solid var(--sumi)}
.results{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px;border-top:1px solid var(--line);padding-top:24px}
.results div{display:flex;flex-direction:column;gap:6px;font-size:13px;color:var(--ash)}
.results output{font-family:var(--latin);font-size:30px;color:var(--washi)}
.results .save output{color:var(--ember-soft)}
.payback{display:flex;flex-wrap:wrap;align-items:baseline;gap:16px;border:1px solid var(--ember);padding:20px 26px;background:var(--sumi)}
.payback output{font-family:var(--mincho);font-size:40px;font-weight:700}

/* cards / news */
.duo{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}
.card{border:1px solid var(--line);background:var(--sumi);padding:clamp(24px,3vw,40px);display:flex;flex-direction:column;gap:14px}
.card time,.card .meta{font-size:13px;color:var(--gold);letter-spacing:.12em}
.card h3{font-size:24px}
.card p{font-size:14px;color:#cfc4b3}

/* CTA */
.cta{text-align:center;display:flex;flex-direction:column;align-items:center;gap:28px}

.cta h2{font-size:clamp(28px,3.6vw,44px);letter-spacing:.1em}
.cta .row{display:flex;flex-wrap:wrap;gap:14px;justify-content:center}

/* tables */
.table-wrap{overflow-x:auto;border:1px solid var(--line)}
table{border-collapse:collapse;width:100%;min-width:640px;font-size:14px}
th,td{padding:14px 18px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
thead th{background:var(--kiln);font-weight:500;color:var(--gold);letter-spacing:.08em;font-size:13px}
tbody th{font-weight:500;color:#d9cfbf;white-space:nowrap}
td.hl{color:var(--ember-soft)}

/* steps (real sequence) */
.steps{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:20px;counter-reset:s}
.steps li{counter-increment:s;border-top:1px solid #3a2f25;padding-top:20px}
.steps li::before{content:counter(s);display:block;font-family:var(--latin);font-size:40px;color:var(--ember);line-height:1;margin-bottom:12px}
.steps h3{font-size:19px;margin-bottom:8px}
.steps p{font-size:14px;color:#cfc4b3}

/* hotspot diagram */
.diagram{position:relative}
.diagram img{width:100%}
.hot{position:absolute;width:44px;height:44px;border-radius:50%;border:2px solid #fff;background:rgba(226,103,44,.85);color:#1a0f08;font-weight:700;font-family:var(--latin);font-size:18px;cursor:pointer;transform:translate(-50%,-50%);box-shadow:0 0 0 6px rgba(226,103,44,.25)}
.hot[aria-expanded=true]{background:#fff}
.hot-panel{margin-top:20px;border:1px solid var(--line);background:var(--kiln);padding:24px 28px;min-height:132px}
.hot-panel h3{font-size:22px;margin-bottom:8px}
.hot-panel p{color:#cfc4b3;font-size:15px}

/* faq */
.faq details{border-bottom:1px solid var(--line)}
.faq summary{cursor:pointer;padding:22px 0;font-family:var(--mincho);font-size:19px;font-weight:700;letter-spacing:.04em;list-style:none;display:flex;justify-content:space-between;gap:20px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-family:var(--latin);font-size:26px;color:var(--ember);line-height:1}
.faq details[open] summary::after{content:"−"}
.faq details p{padding:0 0 24px;color:#cfc4b3;font-size:15px;max-width:52em}

/* science chapters */
.chapters{display:grid;grid-template-columns:220px minmax(0,1fr);gap:clamp(32px,5vw,72px)}
.toc{position:sticky;top:110px;align-self:start;font-size:14px}
.toc ol{list-style:none;margin:0;padding:0;counter-reset:c;border-left:1px solid var(--line)}
.toc li{counter-increment:c}
.toc a{display:block;padding:8px 0 8px 18px;color:var(--ash);text-decoration:none;margin-left:-1px;border-left:1px solid transparent}
.toc a::before{content:counter(c) "　";font-family:var(--latin);color:#6d5e4e}
.toc a.on{color:var(--washi);border-left-color:var(--ember)}
.chapter{padding-bottom:96px;margin-bottom:96px;border-bottom:1px solid var(--line)}
.chapter:last-child{border-bottom:0;margin-bottom:0}
.chapter .no{font-family:var(--latin);font-size:15px;color:var(--ember);letter-spacing:.1em;display:block;margin-bottom:10px}
.chapter h2{font-size:clamp(28px,3.4vw,42px);margin-bottom:28px}
.chapter p{max-width:40em;color:#d6ccbc}
.chapter p+p{margin-top:18px}
.chapter figure{margin:36px 0 0}
.trio{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;margin-top:36px}
.trio div{border:1px solid var(--line);padding:22px;background:var(--kiln)}
.trio h3{font-size:20px;margin-bottom:8px}
.trio p{font-size:14px}
.chart{background:var(--kiln);border:1px solid var(--line);padding:24px;margin-top:32px}
.chart-top{display:flex;flex-wrap:wrap;justify-content:space-between;gap:12px;align-items:center;margin-bottom:14px}
.toggles{display:flex;flex-wrap:wrap;gap:8px}
.toggles button{min-height:44px;padding:0 16px;background:transparent;color:var(--washi);font:inherit;font-size:13px;border:1px solid #6d5e4e;cursor:pointer}
.toggles button[aria-pressed=true]{background:#3a2a1e;border-color:var(--ember)}
.chart svg{width:100%;height:auto}
.analogy{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px;margin-top:32px}
.analogy div{padding:24px;border:1px solid var(--line)}
.analogy h3{font-size:19px;margin-bottom:10px}
.analogy ul{margin:0;padding-left:1.2em;font-size:14px;color:#cfc4b3}

/* forms */
.form{display:grid;gap:22px;max-width:760px}
.field{display:flex;flex-direction:column;gap:8px}
.field label{font-size:14px;letter-spacing:.06em}
.field label .req{color:var(--ember-soft);font-size:12px;margin-left:6px}
.field input,.field select,.field textarea{background:var(--kiln);border:1px solid #3a2f25;color:var(--washi);font:inherit;font-size:16px;padding:12px 14px;min-height:48px}
.field textarea{min-height:180px;resize:vertical}
.field input:focus,.field select:focus,.field textarea:focus{border-color:var(--ember);outline:none}
.hint{font-size:13px;color:var(--ash)}
.form-status{font-size:14px;min-height:1.5em}
.mail-list{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px;margin-top:40px}
.mail-list div{border:1px solid var(--line);padding:18px}
.mail-list b{display:block;font-family:var(--mincho);font-size:17px;margin-bottom:4px}
.mail-list a{font-size:14px}

/* company */
.dl{display:grid;grid-template-columns:200px minmax(0,1fr);border-top:1px solid var(--line)}
.dl dt,.dl dd{margin:0;padding:18px 0;border-bottom:1px solid var(--line)}
.dl dt{color:var(--gold);font-size:14px;letter-spacing:.1em}
.vision{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.vision div{border-top:1px solid var(--gold);padding-top:22px}
.vision span{font-size:13px;color:var(--gold);letter-spacing:.2em}
.vision p{font-family:var(--mincho);font-size:21px;line-height:1.8;margin-top:10px;letter-spacing:.04em}

/* footer */
.site-footer{border-top:1px solid var(--line);padding:56px 0 40px;font-size:13px;color:var(--ash);line-height:2}
.site-footer .wrap{display:grid;grid-template-columns:minmax(0,1.4fr) repeat(2,minmax(0,1fr));gap:40px;max-width:1440px}
.site-footer b{font-family:var(--mincho);font-size:19px;color:var(--washi);letter-spacing:.2em;display:block;margin-bottom:6px;font-weight:700}
.site-footer ul{list-style:none;margin:0;padding:0}
.site-footer a{color:var(--ash);text-decoration:none}
.site-footer a:hover{color:var(--washi)}
.site-footer .copy{grid-column:1 / -1;border-top:1px solid var(--line);padding-top:24px;font-family:var(--latin);letter-spacing:.2em}

/* responsive */
@media (max-width:1080px){
  .plate{grid-template-columns:repeat(2,minmax(0,1fr))}
  .steps{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (max-width:900px){
  .menu-btn{display:inline-flex;align-items:center}
  .nav{position:fixed;inset:76px 0 auto 0;background:var(--sumi);border-bottom:1px solid var(--line);flex-direction:column;align-items:stretch;padding:12px var(--gutter) 28px;gap:18px;display:none}
  .nav.open{display:flex}
  .nav ul{flex-direction:column;gap:0}
  .nav ul a{display:block;padding:14px 0;border-bottom:1px solid var(--line);font-size:16px}
  .section-head,.split,.split.rev,.sim,.chapters{grid-template-columns:minmax(0,1fr)}
  .split.rev figure{order:-1}
  .models,.points,.duo,.trio,.vision,.analogy{grid-template-columns:minmax(0,1fr)}
  .toc{position:static}
  .hero .wrap{grid-template-columns:minmax(0,1fr)}
  .hero h1{grid-column:1;grid-row:auto;writing-mode:horizontal-tb;margin-top:0;font-size:clamp(40px,11vw,64px);letter-spacing:.08em}
  .site-footer .wrap{grid-template-columns:minmax(0,1fr)}
  .dl{grid-template-columns:minmax(0,1fr)}
  .dl dt{padding-bottom:0;border-bottom:0}
}
@media (max-width:560px){
  .plate,.steps,.results{grid-template-columns:minmax(0,1fr)}
  .hero-facts{gap:24px}
}

/* running-cost comparison */
.coal-vs{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;border-top:1px solid var(--line);padding-top:24px}
.coal-vs div{display:flex;flex-direction:column;gap:6px;padding:18px;border:1px solid var(--line);background:var(--sumi);font-size:13px;color:var(--ash)}
.coal-vs output{font-family:var(--latin);font-size:32px;color:var(--washi)}
.coal-vs .us{border-color:var(--ember)}
.coal-vs strong{font-family:var(--mincho);font-size:22px;color:var(--ember-soft);font-weight:700}
.bars{display:flex;flex-direction:column;gap:14px}
.bar{display:grid;grid-template-columns:150px minmax(0,1fr) 110px;gap:14px;align-items:center;font-size:14px}
.bar i{display:block;height:10px;background:#5a4a3b;width:var(--w,0%);transition:width .3s ease}
.bar output{font-family:var(--latin);font-size:22px;text-align:right}
.bar.us span,.bar.us output{color:var(--ember-soft)}
.bar.us i{background:var(--ember)}
@media (prefers-reduced-motion:reduce){.bar i{transition:none}}
@media (max-width:560px){.coal-vs{grid-template-columns:minmax(0,1fr)}.bar{grid-template-columns:minmax(0,1fr) auto}.bar i{grid-column:1 / -1;grid-row:2}}
.section-head p:empty{display:none}
.section-head:has(> p:empty){grid-template-columns:minmax(0,1fr)}
.coal-vs strong{font-size:19px}

/* hero stopwatch: 0.00 -> 4.00 seconds, synced to the video */
.clock{display:flex;flex-direction:column;gap:6px}
.clock-n{font-family:var(--latin);font-weight:600;font-size:clamp(64px,8vw,116px);line-height:.85;color:var(--ember);font-variant-numeric:lining-nums tabular-nums;white-space:nowrap;text-shadow:0 0 calc(var(--g,0) * 36px) rgba(226,103,44,.8)}
.clock-n small{font-family:var(--mincho);font-size:.34em;margin-left:.2em;font-weight:700}
.clock-st{font-family:var(--mincho);font-weight:700;font-size:clamp(18px,2vw,24px);letter-spacing:.14em}
.clock-st.ready{color:var(--ember-soft)}
.chapter figure video{width:100%;height:auto;display:block}