/* ============================================================
   Kikitori Lab — editorial design system
   Ink-on-paper (indigo) + sparing vermilion (shu) accent.
   Newsreader (serif) · Inter (UI) · IBM Plex Mono (labels) · Noto Serif JP
   ============================================================ */

:root{
  --paper:#F3F5F8;
  --paper-2:#E9EDF3;
  --card:#FFFFFF;
  --ink:#16233B;
  --ink-2:#2B3A57;
  --body:#26334C;
  --mist:#647289;
  --line:#D7DEE8;
  --line-soft:#E4E9F0;
  --brand:#2563EB;
  --brand-dark:#1D4ED8;
  --accent:#E0492A;
  --accent-ink:#B23A1C;
  --accent-tint:rgba(224,73,42,.09);
  --brand-tint:rgba(37,99,235,.08);
  --indigo:#2B3A67;

  --serif:'Newsreader', Georgia, 'Times New Roman', serif;
  --sans:'Inter', system-ui, -apple-system, sans-serif;
  --mono:'IBM Plex Mono', ui-monospace, 'SFMono-Regular', monospace;
  --jp:'Noto Serif JP', serif;

  --wrap:1120px;
  --measure:44rem;
  --r:14px;
  --r-sm:10px;
}

*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;
  background:var(--paper);
  color:var(--body);
  font-family:var(--serif);
  font-size:1.125rem;
  line-height:1.75;
  font-optical-sizing:auto;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
img{max-width:100%;display:block}
a{color:var(--brand-dark);text-decoration:none}
a:hover{text-decoration:underline}
::selection{background:var(--accent-tint);color:var(--ink)}

/* ---------- layout ---------- */
.wrap{max-width:var(--wrap);margin-inline:auto;padding-inline:clamp(1.15rem,4vw,2rem)}
.section{padding-block:clamp(3rem,7vw,5.5rem)}
.section--tight{padding-block:clamp(2.25rem,5vw,3.5rem)}
.rule{height:1px;background:var(--line);border:0;margin:0}

/* ---------- typographic roles ---------- */
.eyebrow{
  font-family:var(--mono);
  font-size:.72rem;
  letter-spacing:.19em;
  text-transform:uppercase;
  color:var(--accent-ink);
  font-weight:500;
  margin:0 0 .9rem;
  display:inline-flex;
  align-items:center;
  gap:.55rem;
}
.eyebrow::before{
  content:"";
  width:1.6rem;height:2px;background:var(--accent);display:inline-block;
}
.eyebrow--plain::before{display:none}
h1,h2,h3,h4{font-family:var(--serif);color:var(--ink);font-weight:600;line-height:1.14;letter-spacing:-.01em}
h1{font-size:clamp(2.1rem,5.2vw,3.25rem);margin:.2rem 0 .6rem;font-weight:500}
h2{font-size:clamp(1.5rem,3.1vw,2.05rem);margin:2.6rem 0 .8rem}
h3{font-size:1.28rem;margin:1.9rem 0 .5rem;font-weight:600}
p{margin:0 0 1.15rem}
strong{font-weight:600;color:var(--ink-2)}
em{font-style:italic}
.lede{font-size:1.28rem;line-height:1.62;color:var(--ink-2);margin-bottom:1.6rem}
.jp{font-family:var(--jp)}
.meta{font-family:var(--mono);font-size:.8rem;letter-spacing:.02em;color:var(--mist)}

ruby rt{
  font-family:var(--mono);
  font-size:.5em;
  color:var(--mist);
  font-weight:500;
  letter-spacing:.04em;
}

/* ---------- header ---------- */
.site-head{
  position:sticky;top:0;z-index:60;
  background:rgba(243,245,248,.86);
  backdrop-filter:saturate(140%) blur(10px);
  border-bottom:1px solid var(--line);
}
.site-head__bar{display:flex;align-items:center;justify-content:space-between;height:66px;gap:1rem}
.brand{display:inline-flex;align-items:center;gap:.6rem;font-family:var(--sans)}
.brand__mark{
  width:34px;height:34px;border-radius:9px;background:var(--ink);
  display:grid;place-items:center;flex:0 0 auto;
}
.brand__mark svg{width:20px;height:20px}
.brand__name{font-weight:700;color:var(--ink);font-size:1.06rem;letter-spacing:-.01em;line-height:1}
.brand__sub{display:block;font-family:var(--mono);font-size:.6rem;letter-spacing:.16em;text-transform:uppercase;color:var(--mist);margin-top:2px}
.brand:hover{text-decoration:none}

.nav{display:flex;align-items:center;gap:.35rem;font-family:var(--sans)}
.nav a{
  color:var(--ink-2);font-weight:500;font-size:.95rem;
  padding:.5rem .7rem;border-radius:8px;letter-spacing:-.01em;
}
.nav a:hover{background:var(--paper-2);text-decoration:none}
.nav a[aria-current="page"]{color:var(--ink)}
.nav a[aria-current="page"]::after{
  content:"";display:block;height:2px;background:var(--accent);
  margin-top:2px;border-radius:2px;
}
.nav .btn-app{margin-left:.35rem}

/* CSS-only mobile menu */
.nav-toggle{display:none}
.nav-burger{
  display:none;font-family:var(--sans);align-items:center;gap:.5rem;
  background:var(--card);border:1px solid var(--line);border-radius:9px;
  padding:.5rem .7rem;color:var(--ink);font-weight:600;font-size:.85rem;cursor:pointer;
}
.nav-burger svg{width:18px;height:18px}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;align-items:center;gap:.5rem;font-family:var(--sans);
  font-weight:600;font-size:.95rem;letter-spacing:-.01em;line-height:1;
  padding:.8rem 1.15rem;border-radius:10px;border:1px solid transparent;cursor:pointer;
  transition:transform .15s ease, background .15s ease, box-shadow .15s ease;
}
.btn:hover{text-decoration:none}
.btn svg{width:17px;height:17px}
.btn-app{background:var(--brand);color:#fff;box-shadow:0 1px 0 rgba(16,35,59,.04)}
.btn-app:hover{background:var(--brand-dark);transform:translateY(-1px)}
.btn-ghost{background:transparent;color:var(--ink);border-color:var(--line)}
.btn-ghost:hover{background:var(--card);border-color:var(--mist)}
.btn-ink{background:var(--ink);color:var(--paper)}
.btn-ink:hover{background:#0e1929;transform:translateY(-1px)}
.btn-lg{padding:.95rem 1.4rem;font-size:1rem;border-radius:11px}

/* ---------- hero ---------- */
.hero{position:relative;overflow:hidden;background:
   radial-gradient(120% 90% at 88% -10%, rgba(37,99,235,.06), transparent 55%),
   radial-gradient(90% 70% at -5% 110%, var(--accent-tint), transparent 50%),
   var(--paper);
  border-bottom:1px solid var(--line);
}
.hero__grid{display:grid;grid-template-columns:1.05fr .95fr;gap:clamp(2rem,4vw,3.5rem);align-items:center}
.hero__title{font-size:clamp(2.4rem,5.6vw,3.7rem);font-weight:500;letter-spacing:-.02em;line-height:1.06;margin:.3rem 0 1rem}
.hero__title .u{background:linear-gradient(transparent 62%, var(--accent-tint) 62%);padding:0 .06em}
.hero__lede{font-size:1.24rem;line-height:1.6;color:var(--ink-2);max-width:34rem;margin-bottom:1.7rem}
.hero__cta{display:flex;flex-wrap:wrap;gap:.75rem;align-items:center}
.hero__note{font-family:var(--mono);font-size:.74rem;color:var(--mist);margin-top:1.2rem;letter-spacing:.01em}

/* specimen card (the signature element) */
.specimen-card{
  background:var(--card);border:1px solid var(--line);border-radius:18px;
  box-shadow:0 22px 50px -34px rgba(16,35,59,.5);
  padding:clamp(1.3rem,2.4vw,1.9rem);
}
.specimen-card__head{display:flex;justify-content:space-between;align-items:center;margin-bottom:1.15rem}
.specimen-card__tag{font-family:var(--mono);font-size:.68rem;letter-spacing:.16em;text-transform:uppercase;color:var(--mist)}
.specimen-card__dot{display:inline-flex;gap:5px;align-items:center}
.specimen-card__dot i{width:7px;height:7px;border-radius:50%;background:var(--line)}
.specimen-card__dot i:first-child{background:var(--accent)}
.specimen-card__jp{font-family:var(--jp);font-size:clamp(1.9rem,4.4vw,2.7rem);color:var(--ink);text-align:center;line-height:1.35;margin:.2rem 0 1.25rem}
.tokrow{display:flex;flex-wrap:wrap;justify-content:center;gap:.55rem;margin-bottom:1.2rem}
.tok{
  display:flex;flex-direction:column;align-items:center;gap:.15rem;
  padding:.55rem .7rem;border-radius:10px;background:var(--paper);border:1px solid var(--line-soft);
  transition:all .3s ease;min-width:3.4rem;
}
.tok__jp{font-family:var(--jp);font-size:1.15rem;color:var(--ink-2);font-weight:600;line-height:1.2}
.tok__en{font-family:var(--mono);font-size:.66rem;color:var(--mist);letter-spacing:.01em;text-align:center}
.tok.is-active{background:var(--accent-tint);border-color:var(--accent);transform:translateY(-3px)}
.tok.is-active .tok__jp{color:var(--accent-ink)}
.tok.is-active .tok__en{color:var(--accent-ink)}
.specimen-card__foot{border-top:1px solid var(--line-soft);padding-top:.95rem;text-align:center}
.specimen-card__en{font-size:1.05rem;color:var(--ink-2);margin:0}
.specimen-card__phase{font-family:var(--mono);font-size:.66rem;letter-spacing:.14em;text-transform:uppercase;color:var(--accent-ink);margin-top:.65rem}

/* ---------- stat strip ---------- */
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--line);border:1px solid var(--line);border-radius:var(--r);overflow:hidden}
.stat{background:var(--card);padding:1.35rem 1.1rem;text-align:center}
.stat__n{font-family:var(--serif);font-size:1.9rem;font-weight:600;color:var(--ink);line-height:1}
.stat__l{font-family:var(--mono);font-size:.68rem;letter-spacing:.12em;text-transform:uppercase;color:var(--mist);margin-top:.5rem}
.stat__n em{color:var(--accent-ink);font-style:normal}

/* ---------- guide cards ---------- */
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(19rem,1fr));gap:1.1rem}
.card{
  background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  padding:1.5rem 1.5rem 1.35rem;display:flex;flex-direction:column;
  transition:border-color .18s ease, transform .18s ease, box-shadow .18s ease;
}
.card:hover{border-color:var(--mist);transform:translateY(-2px);box-shadow:0 18px 40px -30px rgba(16,35,59,.45);text-decoration:none}
.card__cat{font-family:var(--mono);font-size:.66rem;letter-spacing:.14em;text-transform:uppercase;color:var(--accent-ink);margin-bottom:.7rem}
.card__t{font-size:1.32rem;line-height:1.2;color:var(--ink);margin:0 0 .5rem;font-weight:600}
.card__d{font-size:1rem;line-height:1.55;color:var(--mist);margin:0 0 1.1rem;flex:1}
.card__more{font-family:var(--sans);font-size:.86rem;font-weight:600;color:var(--brand-dark);display:inline-flex;align-items:center;gap:.35rem}
.card__more svg{width:15px;height:15px;transition:transform .18s ease}
.card:hover .card__more svg{transform:translateX(3px)}

/* ---------- method / feature rows ---------- */
.feat{display:grid;grid-template-columns:repeat(3,1fr);gap:1.6rem}
.feat__item{border-top:2px solid var(--ink);padding-top:1.05rem}
.feat__k{font-family:var(--mono);font-size:.72rem;letter-spacing:.06em;color:var(--accent-ink);margin-bottom:.5rem}
.feat__t{font-size:1.24rem;color:var(--ink);font-weight:600;margin:0 0 .45rem}
.feat__p{font-size:1rem;line-height:1.6;color:var(--body);margin:0}

/* ---------- band (dark) ---------- */
.band{background:var(--ink);color:#DCE3EE}
.band h2{color:#fff}
.band .lede{color:#B8C4D6}
.band .eyebrow{color:#F2A58F}
.band .eyebrow::before{background:var(--accent)}
.band a.btn-ghost{color:#fff;border-color:rgba(255,255,255,.25)}
.band a.btn-ghost:hover{background:rgba(255,255,255,.06);border-color:rgba(255,255,255,.5)}

/* ---------- article ---------- */
.article{max-width:var(--measure);margin-inline:auto;padding-block:clamp(2.25rem,5vw,3.5rem)}
.article__head{margin-bottom:1.6rem}
.article__meta{display:flex;flex-wrap:wrap;gap:.5rem 1.1rem;align-items:center;margin-top:1rem;padding-top:1rem;border-top:1px solid var(--line)}
.tag{font-family:var(--mono);font-size:.68rem;letter-spacing:.1em;text-transform:uppercase;color:var(--ink-2);background:var(--paper-2);border:1px solid var(--line);border-radius:100px;padding:.28rem .7rem}
.tag--accent{color:var(--accent-ink);background:var(--accent-tint);border-color:transparent}
.prose{font-size:1.155rem;line-height:1.78}
.prose h2{scroll-margin-top:84px;display:flex;align-items:baseline;gap:.7rem}
.prose h2 .n{font-family:var(--mono);font-size:.82rem;color:var(--accent);font-weight:500;flex:0 0 auto}
.prose ul,.prose ol{margin:0 0 1.3rem;padding-left:1.35rem}
.prose li{margin-bottom:.55rem;padding-left:.2rem}
.prose li::marker{color:var(--accent)}
.prose ol li::marker{font-family:var(--mono);font-size:.85rem;color:var(--accent-ink)}
.prose a{border-bottom:1px solid rgba(37,99,235,.35);color:var(--brand-dark)}
.prose a:hover{border-bottom-color:var(--brand-dark);text-decoration:none}
.prose blockquote{margin:1.8rem 0;padding:.2rem 0 .2rem 1.4rem;border-left:3px solid var(--accent);font-style:italic;color:var(--ink-2);font-size:1.24rem;line-height:1.55}

/* callouts */
.callout{
  background:var(--card);border:1px solid var(--line);border-left:3px solid var(--accent);
  border-radius:var(--r-sm);padding:1.15rem 1.3rem;margin:1.8rem 0;
}
.callout__k{font-family:var(--mono);font-size:.68rem;letter-spacing:.13em;text-transform:uppercase;color:var(--accent-ink);margin:0 0 .45rem}
.callout p:last-child{margin-bottom:0}
.callout--app{border-left-color:var(--brand);background:linear-gradient(0deg,var(--brand-tint),var(--brand-tint)),var(--card)}
.callout--app .callout__k{color:var(--brand-dark)}

/* specimen (in-article) */
.specimen{
  background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  padding:1.3rem 1.4rem;margin:1.8rem 0;
}
.specimen figcaption{font-family:var(--mono);font-size:.66rem;letter-spacing:.14em;text-transform:uppercase;color:var(--mist);margin-bottom:.7rem}
.specimen__jp{font-family:var(--jp);font-size:1.7rem;color:var(--ink);line-height:1.4;margin:0 0 .9rem}
.specimen__tokens{display:flex;flex-wrap:wrap;gap:.45rem;margin-bottom:.9rem}
.specimen__tokens .tok{padding:.4rem .6rem;min-width:0}
.specimen__tokens .tok__jp{font-size:1rem}
.specimen__en{font-size:1rem;color:var(--ink-2);margin:0;padding-top:.7rem;border-top:1px solid var(--line-soft)}
.specimen__en b{font-family:var(--mono);font-size:.7rem;letter-spacing:.08em;text-transform:uppercase;color:var(--mist);font-weight:500;margin-right:.5rem}

/* related */
.related{margin-top:3rem;padding-top:2rem;border-top:2px solid var(--ink)}
.related__k{font-family:var(--mono);font-size:.72rem;letter-spacing:.14em;text-transform:uppercase;color:var(--accent-ink);margin-bottom:1.1rem}
.related__list{display:grid;grid-template-columns:1fr 1fr;gap:.9rem}
.related__item{display:block;padding:1rem 1.1rem;border:1px solid var(--line);border-radius:var(--r-sm);background:var(--card)}
.related__item:hover{border-color:var(--mist);text-decoration:none}
.related__item .c{font-family:var(--mono);font-size:.62rem;letter-spacing:.12em;text-transform:uppercase;color:var(--mist)}
.related__item .t{display:block;color:var(--ink);font-weight:600;font-size:1.05rem;margin-top:.25rem;line-height:1.25}

/* toc / index intro */
.pagehead{background:var(--paper);border-bottom:1px solid var(--line)}
.pagehead .lede{max-width:42rem}

/* legal prose */
.doc{max-width:46rem;margin-inline:auto;padding-block:clamp(2rem,5vw,3.25rem)}
.doc h2{font-size:1.4rem;margin-top:2.2rem}
.doc h3{font-size:1.12rem}
.doc p,.doc li{font-size:1.05rem;line-height:1.7}
.doc .updated{font-family:var(--mono);font-size:.76rem;color:var(--mist);margin-bottom:1.6rem}
.ph{background:var(--accent-tint);color:var(--accent-ink);font-family:var(--mono);font-size:.86em;padding:.05em .4em;border-radius:5px;border:1px dashed rgba(224,73,42,.4)}

/* ---------- footer ---------- */
.site-foot{background:var(--ink);color:#AAB6C8;margin-top:2rem}
.site-foot__top{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:2rem;padding-block:3rem}
.site-foot__brand .brand__name{color:#fff}
.site-foot__brand p{color:#8D9BB2;font-size:1rem;max-width:26rem;margin:.9rem 0 0;line-height:1.6}
.foot-col h4{font-family:var(--mono);font-size:.68rem;letter-spacing:.15em;text-transform:uppercase;color:#6E7E97;font-weight:500;margin:0 0 .9rem}
.foot-col a{display:block;color:#C3CDDC;font-family:var(--sans);font-size:.95rem;padding:.28rem 0}
.foot-col a:hover{color:#fff;text-decoration:none}
.site-foot__bottom{border-top:1px solid rgba(255,255,255,.09);padding-block:1.3rem;display:flex;flex-wrap:wrap;justify-content:space-between;gap:.6rem}
.site-foot__bottom p{margin:0;font-family:var(--mono);font-size:.74rem;color:#6E7E97;letter-spacing:.02em}
.site-foot__bottom .jpword{color:#8D9BB2}

/* ---------- 404 ---------- */
.oops{text-align:center;max-width:38rem;margin-inline:auto;padding-block:clamp(3rem,9vw,6rem)}
.oops__code{font-family:var(--jp);font-size:clamp(4rem,14vw,7rem);color:var(--ink);line-height:1;margin:0}
.oops__code span{color:var(--accent)}

/* ---------- utilities ---------- */
.center{text-align:center}
.mx-auto{margin-inline:auto}
.mt-0{margin-top:0}
.stack-sm>*+*{margin-top:.9rem}
.maxw{max-width:42rem}
.hide-sm{display:initial}

/* ---------- responsive ---------- */
@media (max-width:900px){
  .hero__grid{grid-template-columns:1fr;gap:2rem}
  .feat{grid-template-columns:1fr;gap:1.2rem}
  .site-foot__top{grid-template-columns:1fr 1fr}
  .site-foot__brand{grid-column:1 / -1}
  .stats{grid-template-columns:repeat(2,1fr)}
}
@media (max-width:720px){
  .nav{
    position:absolute;top:66px;left:0;right:0;flex-direction:column;align-items:stretch;
    background:var(--paper);border-bottom:1px solid var(--line);padding:.6rem clamp(1.15rem,4vw,2rem) 1.1rem;gap:.15rem;
    box-shadow:0 20px 30px -24px rgba(16,35,59,.4);
    display:none;
  }
  .nav a{padding:.7rem .3rem;border-radius:8px}
  .nav a[aria-current="page"]::after{display:none}
  .nav a[aria-current="page"]{color:var(--accent-ink)}
  .nav .btn-app{margin:.5rem 0 0;justify-content:center}
  .nav-burger{display:inline-flex}
  .nav-toggle:checked ~ .nav{display:flex}
  .related__list{grid-template-columns:1fr}
  .hero__title{font-size:clamp(2.1rem,8vw,2.9rem)}
}
@media (max-width:440px){
  .stats{grid-template-columns:1fr}
  .brand__sub{display:none}
}

/* ---------- a11y ---------- */
:focus-visible{outline:2.5px solid var(--brand);outline-offset:2px;border-radius:4px}
.skip{position:absolute;left:-999px;top:0;background:var(--ink);color:#fff;padding:.6rem 1rem;border-radius:0 0 8px 0;z-index:100;font-family:var(--sans);font-weight:600}
.skip:focus{left:0}
@media (prefers-reduced-motion:reduce){
  *{animation-duration:.001ms !important;transition-duration:.001ms !important;scroll-behavior:auto}
}