:root{
  --white:#F6F6F3;
  --white-dim:#EAEAE5;
  --charcoal:#2A2D30;
  --black:#121315;
  --black-soft:#1A1C1E;
  --turquoise:#22B8B0;
  --turquoise-deep:#0E3D3A;
  --turquoise-dim:#9FD9D4;
  --line:#D8D8D4;
  --line-dark:rgba(246,246,243,0.14);
  --ink:#1B1C1E;
  --font-en:'Space Grotesk',sans-serif;
  --font-jp:'Zen Kaku Gothic New',sans-serif;
  --wrap:1180px;
  --edge:clamp(20px,5vw,64px);
}
*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto;}
  *{animation-duration:0.001ms !important;animation-iteration-count:1 !important;transition-duration:0.001ms !important;}
}
body{margin:0;background:var(--white);color:var(--ink);font-family:var(--font-jp);-webkit-font-smoothing:antialiased;overflow-x:hidden;}
a{color:inherit;text-decoration:none;}
img,svg{display:block;max-width:100%;}
.en{font-family:var(--font-en);}
.wrap{max-width:var(--wrap);margin:0 auto;padding-left:var(--edge);padding-right:var(--edge);}
.section{position:relative;padding:clamp(56px,9vw,120px) 0;}
.section--dark{background:var(--black);color:var(--white);}
.reveal{opacity:0;transform:translateY(24px);transition:opacity .8s ease, transform .8s ease;}
.reveal.is-visible{opacity:1;transform:translateY(0);}

/* Nav (共通) */
.nav{position:fixed;top:0;left:0;right:0;z-index:100;display:flex;align-items:center;justify-content:space-between;padding:18px var(--edge);color:var(--white);transition:background .4s ease, padding .4s ease, border-color .4s ease;border-bottom:1px solid transparent;}
.nav.scrolled{background:rgba(18,19,21,0.86);backdrop-filter:blur(10px);padding-top:12px;padding-bottom:12px;border-bottom:1px solid var(--line-dark);}
.nav__logo{font-family:var(--font-en);font-weight:600;font-size:19px;letter-spacing:0.01em;}
.nav__links{display:none;gap:32px;list-style:none;margin:0;padding:0;font-size:14.5px;}
.nav__links a{opacity:0.82;transition:opacity .25s ease;position:relative;}
.nav__links a.is-active{opacity:1;}
.nav__links a:hover{opacity:1;}
.nav__links a::after{content:'';position:absolute;left:0;right:0;bottom:-6px;height:1px;background:var(--turquoise);transform:scaleX(0);transform-origin:left;transition:transform .3s ease;}
.nav__links a:hover::after,.nav__links a.is-active::after{transform:scaleX(1);}
@media (min-width:900px){.nav__links{display:flex;}}
.nav__toggle{background:none;border:none;color:var(--white);cursor:pointer;padding:6px;display:flex;flex-direction:column;gap:5px;}
@media (min-width:900px){.nav__toggle{display:none;}}
.nav__toggle span{display:block;width:22px;height:1.5px;background:currentColor;transition:transform .3s ease, opacity .3s ease;}
.nav__toggle.open span:nth-child(1){transform:translateY(6.5px) rotate(45deg);}
.nav__toggle.open span:nth-child(2){opacity:0;}
.nav__toggle.open span:nth-child(3){transform:translateY(-6.5px) rotate(-45deg);}
.mobile-menu{position:fixed;inset:0;z-index:90;background:var(--black);color:var(--white);display:flex;flex-direction:column;justify-content:center;gap:26px;padding:0 var(--edge);transform:translateY(-100%);transition:transform .45s cubic-bezier(.6,0,.2,1);}
.mobile-menu.open{transform:translateY(0);}
.mobile-menu a{font-family:var(--font-en);font-size:32px;font-weight:500;}
.mobile-menu__foot{position:absolute;bottom:32px;left:var(--edge);right:var(--edge);font-size:13px;opacity:.6;display:flex;justify-content:space-between;}

/* Page hero (小型) */
.phero{background:var(--black);color:var(--white);padding:clamp(120px,20vw,180px) 0 clamp(56px,8vw,90px);}
.phero__eyebrow{font-family:var(--font-en);font-size:13px;letter-spacing:.14em;color:var(--turquoise);margin:0 0 16px;}
.phero h1{font-family:var(--font-en);font-weight:700;font-size:clamp(36px,6vw,64px);margin:0 0 20px;}
.phero p{font-size:15.5px;line-height:2;color:#c7cac7;max-width:46ch;margin:0;}

/* Chapters timeline */
.chapters{position:relative;}
.chapters__line{position:absolute;left:calc(var(--edge) + 27px);top:0;bottom:0;width:1px;background:var(--line);}
@media (min-width:760px){.chapters__line{left:50%;transform:translateX(-0.5px);}}
.chapter{position:relative;padding:0 0 clamp(56px,8vw,96px);}
.chapter:last-child{padding-bottom:0;}
.chapter__dot{position:absolute;left:calc(var(--edge) + 27px);top:6px;width:11px;height:11px;border-radius:50%;background:var(--white);border:2px solid var(--turquoise);transform:translateX(-50%);z-index:2;}
@media (min-width:760px){.chapter__dot{left:50%;}}
.chapter__grid{display:grid;gap:18px;padding-left:calc(var(--edge) + 50px);padding-right:var(--edge);}
@media (min-width:760px){
  .chapter__grid{padding:0;grid-template-columns:1fr 60px 1fr;align-items:start;gap:0;}
  .chapter__text{grid-column:1;padding-right:56px;text-align:right;}
  .chapter__visual{grid-column:3;padding-left:56px;}
  .chapter:nth-child(even) .chapter__text{grid-column:3;text-align:left;padding-right:0;padding-left:56px;}
  .chapter:nth-child(even) .chapter__visual{grid-column:1;padding-left:0;padding-right:56px;}
}
.chapter__num{font-family:var(--font-en);font-size:13px;color:var(--turquoise-deep);letter-spacing:.08em;margin:0 0 8px;}
.chapter__title{font-family:var(--font-en);font-weight:700;font-size:clamp(22px,3vw,30px);margin:0 0 14px;}
.chapter__body{font-size:14.5px;line-height:2;color:#4b4f52;margin:0;}
@media (min-width:760px){.chapter:nth-child(even) .chapter__body,.chapter:nth-child(even) .chapter__num,.chapter:nth-child(even) .chapter__title{text-align:left;}}
.ph{position:relative;overflow:hidden;background:linear-gradient(150deg,var(--charcoal) 0%,var(--black) 100%);aspect-ratio:4/3;margin-top:18px;}
@media (min-width:760px){.ph{margin-top:0;}}
.ph::before{content:'';position:absolute;inset:0;background:repeating-linear-gradient(115deg, rgba(34,184,176,0.06) 0 2px, transparent 2px 26px);}
.ph__cap{position:absolute;left:14px;bottom:12px;font-size:11.5px;font-weight:500;color:rgba(246,246,243,.55);display:flex;align-items:center;gap:8px;}
.ph__cap i{width:5px;height:5px;border-radius:50%;background:var(--turquoise);display:inline-block;flex:none;}

/* Closing */
.closing{text-align:center;}
.closing blockquote{margin:0 auto;max-width:20ch;font-family:var(--font-jp);font-weight:700;font-size:clamp(24px,4vw,34px);line-height:1.7;}
.closing p{color:#c7cac7;max-width:44ch;margin:22px auto 0;line-height:2;font-size:14.5px;}
.closing__cta{display:flex;gap:16px;justify-content:center;flex-wrap:wrap;margin-top:36px;}
.btn{font-family:var(--font-en);font-size:13.5px;font-weight:600;padding:13px 26px;border-radius:100px;border:1px solid var(--line-dark);transition:border-color .25s ease, background .25s ease;}
.btn:hover{border-color:var(--turquoise);}
.btn--solid{background:var(--turquoise);color:var(--black);border-color:var(--turquoise);}
.btn--solid:hover{background:#3fd0c7;}

/* Footer (共通) */
.foot{position:relative;padding:40px var(--edge) 30px;border-top:1px solid var(--line-dark);overflow:hidden;}
.foot::before{content:'';position:absolute;inset:0;pointer-events:none;opacity:.5;background-image:repeating-linear-gradient(118deg, rgba(34,184,176,0.05) 0px, rgba(34,184,176,0.05) 3px, transparent 3px, transparent 22px);-webkit-mask-image:linear-gradient(to top, rgba(0,0,0,.9), transparent 75%);mask-image:linear-gradient(to top, rgba(0,0,0,.9), transparent 75%);}
.foot > *{position:relative;z-index:1;}
.foot__grid{display:flex;flex-wrap:wrap;justify-content:space-between;gap:24px;align-items:flex-end;}
.foot__mark{font-family:var(--font-en);font-weight:600;font-size:17px;}
.foot__origin{font-size:12px;color:#8a8d8a;margin-top:8px;max-width:36ch;line-height:1.7;}
.foot__links{display:flex;gap:20px;list-style:none;padding:0;margin:0;font-size:13px;flex-wrap:wrap;}
.foot__bottom{margin-top:26px;padding-top:18px;border-top:1px solid var(--line-dark);font-size:11.5px;color:#71746f;display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px;}