:root{
  --ink:#14181d;--ink-soft:#3c434b;--mut:#70777f;--line:#e6e4df;
  --paper:#ffffff;--paper-warm:#f7f5f1;--accent:#e2502b;--accent-dark:#c43e1d;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:'Inter','Noto Sans JP',-apple-system,BlinkMacSystemFont,'Hiragino Sans',sans-serif;color:var(--ink);background:var(--paper);line-height:1.72;font-size:16.5px;-webkit-font-smoothing:antialiased}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
.wrap{max-width:1160px;margin:0 auto;padding:0 28px}
.narrow{max-width:820px}

/* ---------- nav ---------- */
nav{position:fixed;top:0;left:0;right:0;z-index:60;background:rgba(255,255,255,.92);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}
.nav-in{max-width:1160px;margin:0 auto;padding:0 28px;height:64px;display:flex;align-items:center;gap:32px}
.wordmark{font-weight:800;font-size:17px;letter-spacing:.22em;text-transform:uppercase}
.wordmark i{font-style:normal;color:var(--accent)}
.nav-links{display:flex;gap:26px;font-size:14px;font-weight:500;color:var(--ink-soft);margin-left:auto}
.nav-links a:hover{color:var(--ink)}
.nav-cta{background:var(--ink);color:#fff;font-size:13.5px;font-weight:600;padding:9px 20px;border-radius:6px}
.nav-cta:hover{background:#000}
.lang{font-size:13px;color:var(--mut);border:1px solid var(--line);border-radius:6px;padding:7px 14px}
.lang:hover{border-color:var(--ink);color:var(--ink)}

/* ---------- hero ---------- */
.hero{position:relative;min-height:94vh;display:flex;align-items:flex-end;color:#fff}
.hero::before{content:'';position:absolute;inset:0;background:url('img/float.jpg') center 32%/cover no-repeat}
.hero::after{content:'';position:absolute;inset:0;background:linear-gradient(178deg,rgba(10,14,19,.42) 0%,rgba(10,14,19,.06) 42%,rgba(10,14,19,.82) 100%)}
.hero-in{position:relative;z-index:2;width:100%;max-width:1160px;margin:0 auto;padding:140px 28px 0}
.overline{font-size:12.5px;font-weight:700;letter-spacing:.22em;text-transform:uppercase;color:#ffd9cc;margin-bottom:22px}
h1{font-size:clamp(38px,5.6vw,68px);line-height:1.08;font-weight:800;letter-spacing:-.022em;max-width:760px}
.hero .sub{margin-top:26px;font-size:clamp(16px,1.75vw,19.5px);line-height:1.65;max-width:600px;color:rgba(255,255,255,.92)}
.cta-row{margin-top:38px;display:flex;gap:14px;flex-wrap:wrap;align-items:center}
.btn{display:inline-block;border-radius:8px;padding:16px 32px;font-weight:600;font-size:16px;letter-spacing:.01em;transition:.16s;border:none;cursor:pointer;font-family:inherit}
.btn-solid{background:var(--accent);color:#fff}
.btn-solid:hover{background:var(--accent-dark)}
.btn-ghost{border:1px solid rgba(255,255,255,.55);color:#fff;background:transparent}
.btn-ghost:hover{background:rgba(255,255,255,.12)}
.hero-facts{position:relative;z-index:2;max-width:1160px;margin:64px auto 0;padding:0 28px 0}
.facts-in{display:grid;grid-template-columns:repeat(4,1fr);border-top:1px solid rgba(255,255,255,.28)}
.fact{padding:22px 18px 30px 0}
.fact b{display:block;font-size:15px;font-weight:700;letter-spacing:.01em}
.fact span{font-size:13.5px;color:rgba(255,255,255,.75)}

/* ---------- sections ---------- */
section{padding:104px 0}
section.warm{background:var(--paper-warm)}
.kicker{display:flex;align-items:baseline;gap:14px;font-size:12.5px;font-weight:700;letter-spacing:.22em;text-transform:uppercase;color:var(--accent);margin-bottom:24px}
.kicker::after{content:'';flex:0 0 44px;height:1px;background:var(--line);transform:translateY(-4px)}
h2{font-size:clamp(28px,3.6vw,44px);line-height:1.22;font-weight:800;letter-spacing:-.018em;max-width:780px}
.lead{margin-top:22px;font-size:17.5px;color:var(--ink-soft);max-width:680px}

/* problem */
.cols3{display:grid;grid-template-columns:repeat(3,1fr);gap:0;margin-top:56px;border-top:1px solid var(--line)}
.col{padding:32px 36px 0 0;border-right:1px solid var(--line);margin-right:36px}
.col:last-child{border-right:none;margin-right:0}
.col .num{font-size:13px;font-weight:700;color:var(--mut);letter-spacing:.08em;display:block;margin-bottom:14px}
.col b{font-size:18px;font-weight:700;display:block;margin-bottom:10px;letter-spacing:-.01em}
.col p{font-size:15px;color:var(--mut);line-height:1.75}

/* split rows */
.split{display:grid;grid-template-columns:1fr 1fr;gap:72px;align-items:center;margin-top:60px}
.split img{border-radius:4px}
.split h3{font-size:21px;font-weight:700;letter-spacing:-.01em;margin-bottom:10px}
.split p{color:var(--ink-soft);font-size:16px;margin-bottom:22px}
.plain{list-style:none}
.plain li{padding:14px 0;border-bottom:1px solid var(--line);font-size:15.5px;color:var(--ink-soft)}
.plain li:first-child{border-top:1px solid var(--line)}
.plain li b{color:var(--ink);font-weight:600}

/* steps */
.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:28px;margin-top:60px}
.step img{aspect-ratio:4/3;object-fit:cover;width:100%;border-radius:4px}
.step .n{font-size:13px;font-weight:700;letter-spacing:.14em;color:var(--accent);display:block;margin:20px 0 8px}
.step b{display:block;font-size:17px;font-weight:700;letter-spacing:-.01em;margin-bottom:7px}
.step p{font-size:14.5px;color:var(--mut);line-height:1.7}

/* engineering */
.eng{display:grid;grid-template-columns:1fr 1fr;gap:72px;align-items:center;margin-top:60px}
.eng-fig{background:#fff;border:1px solid var(--line);border-radius:4px;padding:34px}
.eng-fig figcaption{margin-top:18px;font-size:12.5px;color:var(--mut);letter-spacing:.04em;border-top:1px solid var(--line);padding-top:14px}
.eng-list{list-style:none;counter-reset:eng}
.eng-list li{padding:22px 0;border-bottom:1px solid var(--line)}
.eng-list li:first-child{border-top:1px solid var(--line)}
.eng-list b{display:block;font-size:17px;font-weight:700;letter-spacing:-.01em;margin-bottom:5px}
.eng-list p{font-size:15px;color:var(--mut);line-height:1.72}

/* specs */
.spec-table{width:100%;border-collapse:collapse;margin-top:52px;font-size:15px}
.spec-table th{font-size:13px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--mut);text-align:left;padding:0 18px 14px 0;border-bottom:2px solid var(--ink)}
.spec-table td{padding:16px 18px 16px 0;border-bottom:1px solid var(--line);vertical-align:top;color:var(--ink-soft)}
.spec-table td:first-child{font-weight:600;color:var(--ink);white-space:nowrap}
.note{margin-top:18px;font-size:13px;color:var(--mut);max-width:680px}

/* reserve */
.reserve{display:grid;grid-template-columns:1fr 1fr;gap:80px;margin-top:56px;align-items:start}
.price-line{display:flex;align-items:baseline;gap:14px;margin:26px 0 8px}
.price-line .p{font-size:46px;font-weight:800;letter-spacing:-.02em}
.price-line .c{font-size:16px;color:var(--mut)}
.reserve .fine{font-size:14.5px;color:var(--mut);max-width:440px}
form{display:grid;gap:12px}
label{font-size:12.5px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--mut)}
input,select,textarea{width:100%;padding:14px 16px;border-radius:6px;border:1px solid #cfccc6;background:#fff;font-size:15.5px;font-family:inherit;color:var(--ink)}
input:focus,select:focus{outline:2px solid var(--ink);outline-offset:-1px;border-color:var(--ink)}
form .btn-solid{width:100%;margin-top:6px}
.form-fine{font-size:12.5px;color:var(--mut);text-align:center}
.trade{margin-top:34px;padding-top:26px;border-top:1px solid var(--line);font-size:14.5px;color:var(--ink-soft)}
.trade b{font-weight:700;color:var(--ink)}

/* faq */
.faq-list{margin-top:48px;max-width:820px}
details{border-bottom:1px solid var(--line)}
details:first-child{border-top:1px solid var(--line)}
summary{padding:22px 44px 22px 0;font-weight:600;font-size:17px;letter-spacing:-.01em;cursor:pointer;list-style:none;position:relative}
summary::-webkit-details-marker{display:none}
summary::after{content:'+';position:absolute;right:4px;top:18px;font-size:22px;font-weight:400;color:var(--mut)}
details[open] summary::after{content:'\2212'}
details .a{padding:0 0 24px;color:var(--ink-soft);font-size:15.5px;max-width:700px}

/* footer */
footer{border-top:1px solid var(--line);padding:56px 0 64px;font-size:14px;color:var(--mut)}
.foot{display:flex;justify-content:space-between;gap:28px;flex-wrap:wrap;align-items:baseline}
.foot .wordmark{font-size:15px;color:var(--ink)}

@media(max-width:920px){
  .cols3{grid-template-columns:1fr}
  .col{border-right:none;margin-right:0;padding-right:0;border-bottom:1px solid var(--line);padding-bottom:28px}
  .col:last-child{border-bottom:none}
  .split,.eng,.reserve{grid-template-columns:1fr;gap:40px}
  .steps{grid-template-columns:1fr 1fr}
  .facts-in{grid-template-columns:1fr 1fr}
  .nav-links{display:none}
  section{padding:76px 0}
}
@media(max-width:560px){.steps{grid-template-columns:1fr}}

/* v3 additions */
.mark{display:inline-block;vertical-align:-7px;margin-right:9px}
.cmp td:last-child{color:var(--ink);font-weight:600}
.cmp th:last-child{color:var(--accent)}
.comic{margin-top:56px}
.comic img{width:100%;border-radius:6px;border:1px solid var(--line)}
.comic-caps{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-top:14px}
.comic-caps div{font-size:13.5px;color:var(--mut);text-align:center}
.comic-caps b{display:block;font-size:12px;letter-spacing:.16em;color:var(--accent);margin-bottom:2px}
.gallery{display:grid;grid-template-columns:repeat(3,1fr);gap:22px;margin:52px 0 8px}
.gallery figure{margin:0}
.gallery img{aspect-ratio:4/3;object-fit:cover;width:100%;border-radius:6px}
.gallery figcaption{font-size:13.5px;color:var(--mut);margin-top:10px;letter-spacing:.02em}
.a-img{margin:16px 0 6px;border-radius:6px;max-width:560px;width:100%}
.safety{margin-top:34px;padding:18px 22px;border-left:3px solid var(--accent);background:var(--paper-warm);font-size:14.5px;color:var(--ink-soft);max-width:820px}
.safety b{color:var(--ink)}
@media(max-width:700px){.comic-caps{grid-template-columns:1fr 1fr}.gallery{grid-template-columns:1fr}}

/* v4: brand / band / science / partners */
::selection{background:var(--accent);color:#fff}
.band{background:var(--ink);color:#fff;padding:100px 0}
.band .kicker{color:#ffb49b}
.band .kicker::after{background:#3a424c}
.band h2{color:#fff}
.band p{margin-top:26px;color:#c3c9d1;max-width:700px;font-size:17px;line-height:1.85}
.band .sig{margin-top:40px;display:flex;align-items:center;gap:12px;font-weight:800;letter-spacing:.24em;font-size:14px}
.sci-facts{display:grid;grid-template-columns:repeat(4,1fr);border-top:1px solid var(--line);border-bottom:1px solid var(--line);margin:56px 0 6px}
.sci{padding:28px 24px 28px 0}
.sci b{display:block;font-size:34px;font-weight:800;letter-spacing:-.02em;color:var(--accent);margin-bottom:6px}
.sci span{font-size:13.5px;color:var(--mut);line-height:1.6;display:block}
@media(max-width:700px){.sci-facts{grid-template-columns:1fr 1fr}.sci{padding-right:14px}}