/* ============================================================
   MURANUSHI THEORY ARCHIVE — homepage
   ============================================================ */

:root {
  --paper:      #ece8df;   /* page background        */
  --paper-2:    #f3f0e8;   /* raised panels / cards  */
  --paper-3:    #e4dfd4;   /* quote band             */
  --ink:        #201d18;   /* near-black warm text   */
  --ink-soft:   #514b41;   /* secondary text         */
  --ink-mute:   #8a8275;   /* captions / labels      */
  --line:       #c8c0b1;   /* hairlines              */
  --line-soft:  #d8d2c5;
  --oxblood:    #6e2020;   /* primary action accent  */

  --serif-en: "Cormorant Garamond", "Times New Roman", serif;
  --serif-ja: "Shippori Mincho", "Noto Serif JP", "Yu Mincho", serif;

  --maxw: 1280px;
  --gutter: clamp(20px, 5vw, 72px);
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif-ja);
  font-weight: 400;
  line-height: 1.85;
  letter-spacing: .02em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

/* ---- Shared bits ---------------------------------------- */

.rule {
  display: block;
  width: 46px;
  height: 1px;
  background: var(--ink);
  opacity: .5;
}

.section-title {
  font-family: var(--serif-en);
  font-weight: 500;
  font-size: clamp(1.8rem, 3.3vw, 2.5rem);
  letter-spacing: .14em;
  margin: 0;
}
.section-sub {
  font-size: .82rem;
  color: var(--ink-mute);
  letter-spacing: .35em;
  margin: .35em 0 0;
}

.text-link {
  font-family: var(--serif-en);
  font-size: .9rem;
  letter-spacing: .18em;
  color: var(--ink-soft);
  white-space: nowrap;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: color .3s, border-color .3s;
}
.text-link span { display: inline-block; transition: transform .3s; }
.text-link:hover { color: var(--ink); border-color: var(--line); }
.text-link:hover span { transform: translateX(5px); }

/* ============================================================
   Header
   ============================================================ */

.site-header {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 22px var(--gutter);
  background: transparent;
  backdrop-filter: none;
  border-bottom: 1px solid transparent;
  transition: border-color .4s;
}
.site-header:hover { border-color: var(--line-soft); }

.brand { display: flex; align-items: center; gap: 16px; }
.brand__mark {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: 2.1rem;
  line-height: 1;
  letter-spacing: -.04em;
  padding-right: 16px;
  border-right: 1px solid var(--line);
}
.brand__name { display: flex; flex-direction: column; gap: 3px; }
.brand__en {
  font-family: var(--serif-en);
  font-weight: 500;
  font-size: .92rem;
  letter-spacing: .26em;
}
.brand__ja {
  font-size: .64rem;
  letter-spacing: .42em;
  color: var(--ink-mute);
}

.nav { display: flex; gap: clamp(20px, 2.6vw, 46px); }
.nav a { display: flex; flex-direction: column; align-items: center; gap: 4px; }
.nav__en {
  font-family: var(--serif-en);
  font-weight: 500;
  font-size: .86rem;
  letter-spacing: .2em;
  position: relative;
}
.nav__en::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -4px;
  height: 1px; background: var(--ink); transform: scaleX(0);
  transform-origin: center; transition: transform .35s ease;
}
.nav a:hover .nav__en::after { transform: scaleX(1); }
.nav__ja { font-size: .6rem; letter-spacing: .3em; color: var(--ink-mute); }

.nav-toggle {
  display: none;
  flex-direction: column;
  align-items: flex-end;
  gap: 6px;
  width: 34px;
  padding: 6px 4px;
  background: none; border: none; cursor: pointer;
}
.nav-toggle span { height: 1px; background: var(--ink); transition: transform .3s, opacity .3s, width .3s; }
.nav-toggle span:nth-child(1) { width: 100%; }
.nav-toggle span:nth-child(2) { width: 60%; }
.nav-toggle span:nth-child(3) { width: 80%; }

/* ============================================================
   Hero
   ============================================================ */

.hero {
  position: relative;
  min-height: 125svh;
  display: flex;
  align-items: center;
  overflow: hidden;
  background: #d9cfc3;            /* matches the image's warm field while it loads */
}

.hero__bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  display: block;
}
@media (min-width: 721px) {
  .hero__bg { inset: -190px 0 0 0; }  /* trim top 190px on PC */
}
.hero__bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 62% center;
}
.hero__scrim { display: none; }

.hero__inner {
  position: relative;
  z-index: 2;
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(90px, 12vh, 150px) var(--gutter) clamp(70px, 10vh, 120px);
}
/* On viewports wider than the max content width, the auto-margin already
   creates the side breathing room, so the inner text can sit flush-left.
   Below this width the inner spans the viewport, so it must keep the
   gutter — otherwise tablet-range screens (≈721–1280px) push the hero
   copy against the left edge. */
@media (min-width: 1281px) {
  .hero__inner { padding-left: clamp(2px, 0.5vw, 10px); }
}
/* Tablet range (721–1000px): the background illustration's central figure
   collides with the hero copy when the section is centered vertically.
   Pin the inner to the top of the hero and tighten the title's top margin
   so the lead and CTA stay above the figure. SP layout (≤720px) is a
   separate layout (.hero__inner { display: contents }) and is untouched. */
@media (min-width: 721px) and (max-width: 1000px) {
  .hero { align-items: flex-start; }
  .hero__inner {
    padding-top: clamp(60px, 8vh, 100px);
    padding-bottom: clamp(40px, 6vh, 80px);
  }
  .hero__title { margin-top: clamp(10px, 2vw, 30px); }
}
.hero__text { max-width: 32rem; }
.hero__text .hero__lead + .hero__lead { margin-top: .6em; }

.hero__scroll,
.hero__side {
  position: absolute;
  z-index: 2;
  font-family: var(--serif-en);
  font-size: .66rem;
  letter-spacing: .4em;
  color: var(--ink-mute);
  writing-mode: vertical-rl;
}
.hero__scroll {
  left: clamp(14px, 3vw, 38px);
  bottom: clamp(36px, 6vh, 70px);
}
.hero__scroll::after {
  content: ""; display: block; width: 1px; height: 46px;
  background: var(--line); margin: 12px auto 0;
}
.hero__side {
  right: clamp(12px, 2.4vw, 34px);
  top: 50%; transform: translateY(-50%);
  letter-spacing: .34em;
}

.hero__title {
  font-family: var(--serif-ja);
  font-weight: 500;
  font-size: clamp(1.35rem, 3vw, 2.19rem);
  line-height: 1.45;
  letter-spacing: .05em;
  margin: clamp(50px, 7vw, 95px) 0 30px;
}
.hero__title span { display: block; white-space: nowrap; }
.hero__series { display: none; }
.hero__lead {
  font-size: .78rem;
  line-height: 2.1;
  color: var(--ink-soft);
  letter-spacing: .06em;
  margin: 22px 0 0;
}
.hero__text .rule { margin: 30px 0 0; }

br.sp-only { display: none; }
br.pc-only { display: inline; }

.hero__eq { display: none; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 40px;
  margin-top: 40px;
  padding: 18px 34px;
  border: 1px solid var(--ink);
  font-family: var(--serif-ja);
  font-size: .92rem;
  letter-spacing: .22em;
  color: var(--ink);
  transition: background .4s, color .4s;
}
.btn__arrow { transition: transform .4s; }
.btn:hover { background: var(--ink); color: var(--paper); }
.btn:hover .btn__arrow { transform: translateX(8px); }


/* ============================================================
   Category index
   ============================================================ */

.cats {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 var(--gutter);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.cat {
  display: grid;
  grid-template-columns: auto 1fr;
  grid-template-areas:
    "icon label"
    "desc desc";
  align-items: center;
  column-gap: 16px;
  row-gap: 16px;
  padding: 44px clamp(14px, 2vw, 30px) 40px;
  position: relative;
}
.cat__icon { grid-area: icon; }
.cat__desc { grid-area: desc; }
.cat + .cat::before {
  content: ""; position: absolute; left: 0; top: 22%; bottom: 22%;
  width: 1px; background: var(--line-soft);
}
.cat__icon img {
  width: 64px; height: 64px;
  object-fit: contain;
  mix-blend-mode: multiply;   /* dissolve the light tile into the cream field */
  opacity: .9;
  /* feather the square edges so the image's backdrop melts into the cream */
  -webkit-mask-image: radial-gradient(circle at 50% 50%, #000 62%, transparent 84%);
          mask-image: radial-gradient(circle at 50% 50%, #000 62%, transparent 84%);
  transition: transform .5s ease, opacity .4s;
}
.cat:hover .cat__icon img { transform: scale(1.06); opacity: 1; }
.cat__label {
  grid-area: label;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 5px;
}
.cat__label b {
  font-family: var(--serif-en);
  font-weight: 500;
  font-size: 1.04rem;
  letter-spacing: .16em;
  line-height: 1;
}
.cat__label small { font-size: .68rem; letter-spacing: .24em; color: var(--ink-mute); line-height: 1; }
.cat__desc { font-size: .76rem; color: var(--ink-soft); letter-spacing: .04em; }

/* ============================================================
   Latest studies
   ============================================================ */

.studies {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(56px, 8vw, 104px) var(--gutter);
}
.studies__head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: clamp(30px, 4vw, 52px);
}
.studies__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: clamp(18px, 2vw, 30px);
}
.studies__grid--two {
  grid-template-columns: repeat(4, 1fr);
  gap: clamp(20px, 2.4vw, 32px);
}
.studies__grid--two .card { grid-column: span 1; }
.studies__grid--three {
  grid-template-columns: repeat(4, 1fr);
  gap: clamp(20px, 2.4vw, 32px);
}
.studies__grid--three .card { grid-column: span 1; }

.card a {
  position: relative;
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 0;
  background: transparent;
  border: none;
  transition: transform .4s ease;
}
.card a:hover {
  transform: translateY(-4px);
}
.card__thumb {
  position: relative;
  display: block;
  margin: 0 0 18px;
  aspect-ratio: 4 / 5;
  overflow: hidden;
  background: transparent;
}
.card__no {
  position: absolute;
  top: 10px;
  left: 12px;
  z-index: 1;
  font-family: var(--serif-en);
  font-style: italic;
  font-size: .82rem;
  letter-spacing: .14em;
  color: var(--ink-mute);
}
.card__thumb img {
  width: 100%; height: 100%;
  object-fit: cover;
  mix-blend-mode: multiply;
  transition: transform 1s ease;
}
.card a:hover .card__thumb img { transform: scale(1.05); }
.card__cat {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: .78rem;
  letter-spacing: .04em;
  color: var(--ink-mute);
}
.card__date {
  display: block;
  font-family: var(--serif-en);
  font-size: .885rem;
  letter-spacing: .08em;
  color: var(--ink-mute);
  margin-top: 10px;
}
.card__title {
  font-family: var(--serif-ja);
  font-weight: 600;
  font-size: 1.08rem;
  line-height: 1.5;
  letter-spacing: .04em;
  margin: 6px 0 6px;
}
.card__subtitle {
  font-family: var(--serif-ja);
  font-size: .82rem;
  line-height: 1.6;
  letter-spacing: .04em;
  color: var(--ink-mute);
  margin: 0 0 10px;
}
.card__desc {
  font-size: .74rem;
  line-height: 1.85;
  color: var(--ink-soft);
  margin: 0;
}
.card__foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
  padding-top: 20px;
}
.card__foot time {
  font-family: var(--serif-en);
  font-size: .76rem;
  letter-spacing: .08em;
  color: var(--ink-mute);
}
.card__arrow { color: var(--ink-soft); transition: transform .35s; }
.card a:hover .card__arrow { transform: translateX(6px); }

/* ============================================================
   Learn about studies
   ============================================================ */

.learn {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(56px, 8vw, 104px) var(--gutter);
  border-top: 1px solid var(--line);
}
.learn__inner { display: flex; flex-direction: column; }
.learn__head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 16px;
}
.learn__lead {
  font-family: var(--serif-ja);
  font-size: .9rem;
  line-height: 2;
  letter-spacing: .04em;
  color: var(--ink-soft);
  margin: 0 0 clamp(30px, 4vw, 52px);
}
.learn__carousel {
  position: relative;
  width: 100vw;
  margin-left: calc(50% - 50vw);
}
.learn__grid {
  display: flex;
  gap: clamp(16px, 1.6vw, 24px);
  overflow-x: auto;
  overflow-y: hidden;
  scroll-snap-type: x mandatory;
  scroll-padding-left: var(--gutter);
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
  padding: 4px var(--gutter) 8px;
  scrollbar-width: none;
}
.learn__grid::-webkit-scrollbar { display: none; }
.learn .card {
  flex: 0 0 clamp(260px, 22vw, 340px);
  scroll-snap-align: start;
}
.learn__nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  z-index: 2;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
  transition: background .25s, color .25s, border-color .25s, opacity .25s;
}
.learn__nav:hover { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.learn__nav svg { width: 18px; height: 18px; }
.learn__nav--prev { left: clamp(8px, 1.5vw, 20px); }
.learn__nav--next { right: clamp(8px, 1.5vw, 20px); }
.learn__nav[disabled] { opacity: 0; pointer-events: none; }
.learn .card a { padding: 16px; }
.learn .card__thumb { margin: 0 0 16px; aspect-ratio: 16 / 10; }
.learn .card__title { font-size: .92rem; margin: 8px 0 10px; }
.learn .card__desc { font-size: .74rem; line-height: 1.85; }
.learn .card__cat { font-style: normal; letter-spacing: .12em; font-size: .825rem; }
.learn .card__foot { padding-top: 16px; }
/* Bottom-of-section "see all" link — mobile only (see media query). */
.learn__more--bottom { display: none; }

/* ============================================================
   Key concepts / glossary
   ============================================================ */

.glossary {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(56px, 8vw, 104px) var(--gutter);
  border-top: 1px solid var(--line);
}
.glossary__inner { display: flex; flex-direction: column; }
.glossary__head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 16px;
}
.glossary__lead {
  font-family: var(--serif-ja);
  font-size: .9rem;
  line-height: 2;
  letter-spacing: .04em;
  color: var(--ink-soft);
  margin: 0 0 clamp(30px, 4vw, 52px);
}
.glossary__grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: clamp(16px, 1.6vw, 24px);
}
.term {
  display: flex;
  flex-direction: column;
  padding-top: 28px;
  border-top: 1px solid var(--line-soft);
}
.term__en {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: .82rem;
  letter-spacing: .1em;
  color: var(--ink-mute);
}
.term__title {
  font-family: var(--serif-ja);
  font-weight: 600;
  font-size: 1.35rem;
  letter-spacing: .06em;
  margin: 8px 0 0;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 12px;
}
.term__title > span { flex: 0 0 100%; }
.term__reading {
  font-weight: 400;
  font-size: .72rem;
  letter-spacing: .18em;
  color: var(--ink-mute);
}
.term .rule { margin: 18px 0 16px; }
.term__desc {
  font-family: var(--serif-ja);
  font-size: .84rem;
  line-height: 2;
  letter-spacing: .03em;
  color: var(--ink-soft);
  margin: 0 0 22px;
}
.term__link {
  margin-top: auto;
  align-self: flex-start;
  font-family: var(--serif-en);
  font-size: .82rem;
  letter-spacing: .18em;
  color: var(--ink-soft);
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: color .3s, border-color .3s;
}
.term__link span { display: inline-block; transition: transform .3s; }
.term__link:hover { color: var(--ink); border-color: var(--line); }
.term__link:hover span { transform: translateX(5px); }

/* desktop: hide tab radios + tablist, all terms visible */
.kc-tab-radio { display: none; }
.kc-tablist { display: none; }
/* desktop: mobile-only dictionary showcase stays hidden */
.kc-dict { display: none; }

/* ============================================================
   Volumes — all issues list (ISSN registration friendly)
   ============================================================ */

.volumes {
  background: var(--paper-2);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.volumes__inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(56px, 8vw, 104px) var(--gutter);
  display: flex;
  flex-direction: column;
}
.volumes__head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: clamp(22px, 3vw, 36px);
}

.volumes__journal {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 18px 0;
  margin-bottom: clamp(18px, 2.4vw, 28px);
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
}
.volumes__journal-en {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: 1.1rem;
  letter-spacing: .08em;
  color: var(--ink);
}
.volumes__journal-ja {
  font-family: var(--serif-ja);
  font-size: .82rem;
  letter-spacing: .22em;
  color: var(--ink-mute);
}

.volumes__table { border-top: 1px solid var(--line); }
.volumes__row {
  display: grid;
  grid-template-columns: 1.1fr 1fr 3fr 2.4fr;
  align-items: baseline;
  gap: clamp(14px, 2vw, 28px);
  padding: clamp(18px, 2.4vw, 26px) 4px;
  border-bottom: 1px solid var(--line-soft);
}
.volumes__row--head {
  font-family: var(--serif-en);
  font-size: .7rem;
  letter-spacing: .26em;
  text-transform: uppercase;
  color: var(--ink-mute);
  padding: 14px 4px;
  border-bottom: 1px solid var(--line);
}

.volumes__no {
  display: flex;
  flex-direction: column;
  gap: 4px;
  line-height: 1.25;
}
.volumes__no-en {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: 1.15rem;
  letter-spacing: .08em;
  color: var(--ink);
}
.volumes__no-ja {
  font-family: var(--serif-ja);
  font-size: .7rem;
  letter-spacing: .22em;
  color: var(--ink-mute);
}

.volumes__date {
  font-family: var(--serif-en);
  font-size: .94rem;
  letter-spacing: .1em;
  color: var(--ink-soft);
}

.volumes__title {
  display: flex;
  flex-direction: column;
  gap: 6px;
  line-height: 1.55;
}
.volumes__title-ja {
  font-family: var(--serif-ja);
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: .04em;
  color: var(--ink);
}
.volumes__title-sub {
  font-family: var(--serif-ja);
  font-size: .86rem;
  font-weight: 400;
  letter-spacing: .04em;
  color: var(--ink-soft);
}
.volumes__title-sub em {
  font-family: var(--serif-en);
  font-style: italic;
  font-weight: 500;
}
.volumes__title-en {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: .78rem;
  letter-spacing: .06em;
  color: var(--ink-mute);
}

.volumes__doi {
  font-family: var(--serif-en);
  font-size: .82rem;
  letter-spacing: .04em;
}
.volumes__doi a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--ink-soft);
  border-bottom: 1px solid var(--line);
  padding-bottom: 2px;
  transition: color .3s, border-color .3s;
}
.volumes__doi a:hover { color: var(--ink); border-color: var(--ink); }
.volumes__doi-arrow {
  font-style: normal;
  font-size: .78rem;
  transition: transform .3s;
}
.volumes__doi a:hover .volumes__doi-arrow { transform: translate(2px, -2px); }
.volumes__doi-tba {
  display: inline-block;
  color: var(--ink-mute);
  font-style: italic;
  letter-spacing: .04em;
  border-bottom: 1px dashed var(--line);
  padding-bottom: 2px;
}

/* ---- Meta block (ISSN, 出版地, 発行) ---------------------- */
.volumes__meta {
  margin: clamp(34px, 4vw, 52px) 0 0;
  padding-top: clamp(24px, 3vw, 36px);
  border-top: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.volumes__meta-row {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 24px;
  align-items: baseline;
}
.volumes__meta-row dt {
  font-family: var(--serif-ja);
  font-size: .78rem;
  letter-spacing: .2em;
  color: var(--ink-mute);
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.volumes__meta-row dt small {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: .66rem;
  letter-spacing: .12em;
  color: var(--ink-mute);
  opacity: .85;
}
.volumes__meta-row dd {
  margin: 0;
  font-family: var(--serif-ja);
  font-size: .9rem;
  letter-spacing: .04em;
  color: var(--ink-soft);
}
.volumes__meta-row dd a {
  border-bottom: 1px solid var(--line);
  padding-bottom: 1px;
  transition: color .3s, border-color .3s;
}
.volumes__meta-row dd a:hover { color: var(--ink); border-color: var(--ink); }
.volumes__meta-sep {
  display: inline-block;
  margin: 0 8px;
  color: var(--ink-mute);
}
.volumes__issn-slot {
  display: inline-block;
  font-family: var(--serif-en);
  font-size: .95rem;
  letter-spacing: .3em;
  color: var(--ink-mute);
  padding: 0 10px 2px;
  border-bottom: 1px dashed var(--line);
}

/* ============================================================
   Featured study (Volume I)
   ============================================================ */

.feature {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(40px, 6vw, 90px) var(--gutter);
  border-top: 1px solid var(--line);
}
.feature__inner {
  display: flex;
  flex-direction: column;
  gap: clamp(32px, 4vw, 56px);
}
.feature__body {
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.feature__below {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: clamp(20px, 2.5vw, 30px);
}
.feature__below .feature__text { margin: 0; }

/* ---- Feature accordion (mobile only — PC/tablet show full content) ---- */
.feature__toggle { display: none; }      /* hidden by default on PC + tablet */
.feature__summary { display: none; }     /* mobile-only abstract teaser */
.feature__collapse { display: block; }    /* normal block on PC + tablet */

/* PC: recreate the original media + meta side-by-side layout via grid on
   .feature__inner, using `display: contents` on .feature__collapse so its
   children act as direct grid items. */
@media (min-width: 1025px) {
  .feature__inner {
    display: grid;
    grid-template-columns: minmax(0, 42%) 1fr;
    column-gap: clamp(32px, 5vw, 72px);
    row-gap: clamp(32px, 4vw, 56px);
    align-items: stretch;
  }
  .feature__head    { grid-column: 1 / -1; grid-row: 1; }
  .feature__media   { grid-column: 1;       grid-row: 2; }
  .feature__collapse { display: contents; }
  .feature__body    { grid-column: 2;       grid-row: 2; }
  .feature__below   { grid-column: 1 / -1;  grid-row: 3; }
}

/* ---- Study action buttons ------------------------------- */
.study-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .7rem;
}
.study-actions > .study-link,
.study-actions > .study-group { height: 2.7rem; }

.study-link {
  display: inline-flex;
  align-items: center;
  gap: .55em;
  padding: 0 1.3em;
  font-family: var(--serif-en);
  font-size: .82rem;
  letter-spacing: .2em;
  color: var(--ink);
  border: 1px solid var(--line);
  background: var(--paper-2);
  transition: background .25s, color .25s, border-color .25s;
}
.study-link svg { width: 12px; height: 12px; flex-shrink: 0; }
.study-link:hover { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.study-link--primary {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}
.study-link--primary:hover { background: var(--ink-soft); border-color: var(--ink-soft); }
.study-link--read {
  background: transparent;
  border-color: var(--ink-soft);
  color: var(--ink-soft);
}
.study-link--read:hover { background: var(--ink-soft); color: var(--paper); border-color: var(--ink-soft); }

.study-group {
  display: inline-flex;
  align-items: stretch;
  border: 1px solid var(--line);
  background: var(--paper-2);
}
.study-group__label {
  display: inline-flex;
  align-items: center;
  padding: 0 1.1em;
  font-family: var(--serif-en);
  font-size: .78rem;
  letter-spacing: .3em;
  text-transform: uppercase;
  color: var(--ink-mute);
  background: var(--paper-3);
  border-right: 1px solid var(--line);
  flex-shrink: 0;
}
.study-group a {
  display: inline-flex;
  align-items: center;
  padding: 0 1.1em;
  font-family: var(--serif-ja);
  font-size: .82rem;
  letter-spacing: .14em;
  color: var(--ink);
  transition: background .25s, color .25s;
}
.study-group a + a { border-left: 1px dotted var(--line); }
.study-group a:hover { background: var(--ink); color: var(--paper); }

.feature__media {
  position: relative;
  padding: 10px 0;
  background: radial-gradient(120% 120% at 50% 30%, #f3f0e8 0%, var(--paper-3) 70%, #ddd6c8 100%);
  border: 1px solid var(--line-soft);
}
.feature__media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: contain;
  mix-blend-mode: multiply;
}
.feature__eyebrow {
  display: block;
  font-family: var(--serif-en);
  font-size: .76rem;
  letter-spacing: .22em;
  color: var(--ink-mute);
}
.feature__volume {
  font-family: var(--serif-ja);
  font-weight: 500;
  font-size: clamp(.85rem, 1.6vw, 1.2rem);
  letter-spacing: .22em;
  color: var(--ink-mute);
  margin: 16px 0 0;
}
.feature__title-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: clamp(10px, 1.6vw, 22px);
  margin: 10px 0 0;
}
.feature__title {
  font-family: var(--serif-ja);
  font-weight: 600;
  font-size: clamp(2.1rem, 3.2vw, 2.6rem);
  line-height: 1.3;
  letter-spacing: .08em;
  margin: 0;
  flex-shrink: 0;
}
.feature__subtitle {
  font-family: var(--serif-ja);
  font-weight: 500;
  font-size: clamp(1.42rem, 1.95vw, 1.72rem);
  letter-spacing: .06em;
  color: var(--ink-soft);
  margin: 0;
  min-width: 0;
}
.feature__subtitle em {
  font-family: var(--serif-en);
  font-style: italic;
  font-weight: 600;
}
.feature__head .rule { margin: 24px 0 0; }
.feature__lead {
  font-family: var(--serif-ja);
  font-weight: 500;
  font-size: clamp(1rem, 1.6vw, 1.18rem);
  line-height: 2;
  letter-spacing: .05em;
  margin: 0 0 22px;
}
.feature__lead em {
  font-family: var(--serif-en);
  font-style: italic;
  font-weight: 600;
}
.feature__text {
  font-size: 1.03rem;
  line-height: 2.05;
  color: var(--ink-soft);
  letter-spacing: .04em;
  margin: 0 0 30px;
}
.feature__text--en {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: 1.1rem;
  line-height: 1.85;
  letter-spacing: .02em;
  color: var(--ink-mute);
  margin-top: -14px;
  padding-top: 18px;
  border-top: 1px dotted var(--line-soft);
}
.feature__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px clamp(28px, 4vw, 54px);
  margin: 0 0 36px;
  padding: 22px 0;
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
}
.feature__meta div { display: flex; flex-direction: column; gap: 4px; }
.feature__meta dt {
  font-size: .64rem;
  letter-spacing: .26em;
  color: var(--ink-mute);
}
.feature__meta dd {
  margin: 0;
  font-family: var(--serif-en);
  font-size: .94rem;
  letter-spacing: .06em;
}

/* ---- Study metadata ------------------------------------- */
.study-meta {
  margin: 0;
  padding: 0;
  background: transparent;
  border: none;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  height: 100%;
  min-height: 0;
}
.study-meta__row {
  display: grid;
  grid-template-columns: max-content 1fr;
  align-items: baseline;
  gap: clamp(20px, 4vw, 48px);
  padding: 4px 0;
}
.study-meta dt {
  font-family: var(--serif-en);
  font-size: .82rem;
  letter-spacing: .32em;
  text-transform: uppercase;
  color: var(--ink-mute);
}
.study-meta dd {
  margin: 0;
  font-family: var(--serif-en);
  font-style: italic;
  font-size: 1.18rem;
  letter-spacing: .04em;
  color: var(--ink);
}

/* ---- Study keywords ------------------------------------- */
.study-keywords {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 6px;
  padding: 20px 0 4px;
  border-top: 1px solid var(--line-soft);
}
.study-keywords__row {
  display: grid;
  grid-template-columns: 7.4rem 1fr;
  align-items: baseline;
  gap: clamp(14px, 2vw, 24px);
  margin: 0;
}
.study-keywords__label {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: .74rem;
  letter-spacing: .26em;
  color: var(--ink-mute);
  text-transform: none;
}
.study-keywords__label--en {
  letter-spacing: .32em;
  text-transform: uppercase;
}
.study-keywords__list {
  font-family: var(--serif-ja);
  font-size: .86rem;
  line-height: 1.95;
  letter-spacing: .04em;
  color: var(--ink-soft);
}
.study-keywords__list--en {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: .9rem;
  letter-spacing: .03em;
}
.study-keywords__list em {
  font-family: var(--serif-en);
  font-style: italic;
  font-weight: 600;
}

/* ---- Study cite (accordion) ----------------------------- */
.study-cite {
  width: 100%;
  border: 1px solid var(--line);
  background: var(--paper-2);
}
.study-cite__summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 18px 22px;
  cursor: pointer;
  list-style: none;
  user-select: none;
  transition: background .25s;
}
.study-cite__summary::-webkit-details-marker { display: none; }
.study-cite__summary:hover { background: var(--paper-3); }
.study-cite__label {
  display: inline-flex;
  align-items: baseline;
  gap: .9em;
  flex-wrap: wrap;
}
.study-cite__en {
  font-family: var(--serif-en);
  font-size: .82rem;
  letter-spacing: .28em;
  color: var(--ink);
}
.study-cite__sep {
  color: var(--ink-mute);
  font-family: var(--serif-en);
  letter-spacing: 0;
}
.study-cite__ja {
  font-family: var(--serif-ja);
  font-size: .82rem;
  letter-spacing: .2em;
  color: var(--ink-soft);
}
.study-cite__icon {
  position: relative;
  width: 14px;
  height: 14px;
  flex-shrink: 0;
}
.study-cite__icon::before,
.study-cite__icon::after {
  content: "";
  position: absolute;
  background: var(--ink);
  transition: transform .25s;
}
.study-cite__icon::before {
  top: 50%;
  left: 0;
  right: 0;
  height: 1px;
  transform: translateY(-50%);
}
.study-cite__icon::after {
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
  transform: translateX(-50%);
}
.study-cite[open] .study-cite__icon::after {
  transform: translateX(-50%) scaleY(0);
}
.study-cite__body {
  padding: 4px 22px 22px;
  border-top: 1px solid var(--line-soft);
  background: var(--paper);
}
.cite-block {
  margin: 22px 0 0;
}
.cite-block__label {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: .76rem;
  letter-spacing: .22em;
  color: var(--ink-mute);
  margin-bottom: .55rem;
  text-transform: uppercase;
}
.cite-block__text {
  font-size: .84rem;
  line-height: 1.85;
  color: var(--ink-soft);
  letter-spacing: .03em;
  margin: 0;
  word-break: break-word;
}
.cite-block__text em {
  font-family: var(--serif-en);
  font-style: italic;
}
.cite-block__text a {
  color: var(--ink-soft);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
}
.cite-block__text a:hover {
  color: var(--ink);
  border-color: var(--ink-soft);
}
.cite-block__code {
  font-family: ui-monospace, "SFMono-Regular", Menlo, monospace;
  font-size: .76rem;
  line-height: 1.7;
  color: var(--ink-soft);
  background: var(--paper-3);
  padding: 14px 16px;
  border: 1px solid var(--line-soft);
  border-radius: 2px;
  overflow-x: auto;
  white-space: pre;
  margin: 0;
}

@media (max-width: 720px) {
  .study-keywords__row {
    grid-template-columns: 1fr;
    gap: 4px;
  }
  .study-cite__summary { padding: 14px 16px; }
  .study-cite__body { padding: 4px 16px 18px; }
  .study-cite__en,
  .study-cite__ja { font-size: .78rem; letter-spacing: .22em; }
  .cite-block__text { font-size: .82rem; }
  .cite-block__code { font-size: .7rem; }
}

/* ============================================================
   News
   ============================================================ */

.news {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(56px, 8vw, 104px) var(--gutter);
  border-top: 1px solid var(--line);
}
.news__head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: clamp(30px, 4vw, 52px);
}
.news__timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  margin-left: clamp(140px, 18vw, 200px);
  border-left: 1px solid var(--line);
}
.news-item {
  position: relative;
}
.news-item__link {
  display: block;
  position: relative;
  padding: 30px 0 30px clamp(28px, 3vw, 48px);
  color: inherit;
  text-decoration: none;
  transition: background .35s ease;
}
.news-item + .news-item .news-item__link {
  border-top: 1px solid var(--line);
}
.news-item__link::before {
  content: '';
  position: absolute;
  left: -5px;
  top: 44px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--paper);
  border: 1px solid var(--ink-mute);
  transition: background .35s ease, border-color .35s ease;
}
.news-item__link:hover::before {
  background: var(--ink-mute);
}
.news-item__date {
  position: absolute;
  left: calc(-1 * clamp(140px, 18vw, 200px));
  top: 32px;
  width: clamp(130px, 17vw, 190px);
  padding-right: 22px;
  text-align: right;
  font-family: var(--serif-en);
  font-style: italic;
  font-size: calc(1.45rem - 2px);
  letter-spacing: .06em;
  color: var(--ink);
  line-height: 1.2;
}
.news-item__title {
  font-family: var(--serif-ja);
  font-weight: 600;
  font-size: calc(1.12rem - 2px);
  line-height: 1.55;
  letter-spacing: .04em;
  margin: 0;
  color: var(--ink);
}
.news-item__subtitle {
  display: inline;
  font-family: inherit;
  font-weight: inherit;
  font-size: inherit;
  letter-spacing: inherit;
  color: inherit;
  margin-left: .2em;
}

/* ============================================================
   Archive (reference site)
   ============================================================ */

.archive {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(20px, 4vw, 40px) var(--gutter) clamp(40px, 6vw, 80px);
}
.archive__inner {
  padding: clamp(40px, 6vw, 72px) clamp(28px, 5vw, 72px);
  background:
    radial-gradient(120% 140% at 18% 0%, #f3f0e8 0%, var(--paper-3) 55%, #ddd6c8 100%);
  border: 1px solid var(--line-soft);
}
.archive__head { text-align: center; }
.archive__sup {
  font-family: var(--serif-en);
  font-size: .78rem;
  letter-spacing: .34em;
  color: var(--ink-mute);
  margin: 0;
}
.archive__title {
  font-family: var(--serif-ja);
  font-weight: 600;
  font-size: clamp(1.5rem, 3vw, 2.1rem);
  letter-spacing: .14em;
  margin: 12px 0 10px;
}
.archive__author {
  font-family: var(--serif-en);
  font-size: .82rem;
  letter-spacing: .12em;
  color: var(--ink-soft);
  margin: 0;
}
.archive__desc {
  max-width: 46rem;
  margin: clamp(28px, 4vw, 44px) auto;
  text-align: center;
  font-size: .86rem;
  line-height: 2.1;
  color: var(--ink-soft);
  letter-spacing: .04em;
}
.archive__list {
  list-style: none;
  margin: 0 auto;
  padding: 0;
  max-width: 48rem;
  border-top: 1px solid var(--line-soft);
}
.archive__list li { border-bottom: 1px solid var(--line-soft); }
.archive__list a {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 18px;
  padding: 18px 6px;
  transition: padding .35s ease, color .3s;
}
.archive__list a:hover { padding-left: 18px; }
.archive__en {
  font-family: var(--serif-en);
  font-style: italic;
  font-size: 1.04rem;
  letter-spacing: .04em;
}
.archive__ja {
  font-size: .82rem;
  letter-spacing: .1em;
  color: var(--ink-mute);
  white-space: nowrap;
}
.archive__foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 12px clamp(20px, 4vw, 40px);
  margin-top: clamp(30px, 4vw, 48px);
  font-size: .74rem;
  letter-spacing: .12em;
  color: var(--ink-mute);
  text-align: center;
}
.archive__foot a { border-bottom: 1px solid transparent; transition: border-color .3s; }
.archive__foot a:hover { border-color: var(--line); }

/* ============================================================
   Fragmenta — name philosophy
   背景画像（紙の断片）の上に、右側に寄せた本文を置く。
   ============================================================ */

.fragmenta {
  padding: clamp(36px, 5vw, 72px) var(--gutter) clamp(24px, 3vw, 40px);
  max-width: var(--maxw);
  margin: 0 auto;
}
.fragmenta__frame {
  position: relative;
  padding: clamp(28px, 4vw, 56px) clamp(28px, 4vw, 64px);
  background:
    linear-gradient(90deg,
      rgba(243, 240, 232, 0)    0%,
      rgba(243, 240, 232, 0)    32%,
      rgba(243, 240, 232, .55)  50%,
      rgba(243, 240, 232, .9)   72%,
      rgba(243, 240, 232, .96) 100%),
    url("assets/img/bg-image.png") left center / cover no-repeat,
    var(--paper-2);
  border: 1px solid var(--line-soft);
  overflow: hidden;
  min-height: clamp(280px, 38vw, 460px);
  display: flex;
  align-items: center;
}
.fragmenta__body {
  position: relative;
  z-index: 1;
  margin-left: auto;
  max-width: 560px;
}
.fragmenta__head {
  margin: 0 0 clamp(18px, 2.6vw, 28px);
}
.fragmenta__head .section-title { color: var(--ink); }
.fragmenta__head .section-sub {
  font-family: var(--serif-ja);
  letter-spacing: .28em;
  color: var(--ink-mute);
  margin-top: .6em;
}
.fragmenta__lead {
  margin: 0 0 clamp(18px, 2.4vw, 26px);
  font-family: var(--serif-ja);
  font-weight: 500;
  font-size: clamp(1.18rem, 1.9vw, 1.5rem);
  letter-spacing: .12em;
  line-height: 1.7;
  color: var(--ink);
}
.fragmenta__prose {
  margin: 0 0 clamp(12px, 1.8vw, 18px);
  font-family: var(--serif-ja);
  font-size: .92rem;
  line-height: 2;
  letter-spacing: .08em;
  color: var(--ink-soft);
}
.fragmenta__prose i {
  font-style: italic;
  font-family: var(--serif-en);
  letter-spacing: .04em;
}
.fragmenta__prose--coda {
  margin-top: clamp(18px, 2.6vw, 28px);
  font-weight: 500;
  color: var(--ink);
  letter-spacing: .1em;
}

/* mobile: stack vertically, soften the gradient so the image sits as texture */
@media (max-width: 720px) {
  .fragmenta { padding: clamp(28px, 8vw, 48px) 0; }
  .fragmenta__frame {
    padding: clamp(28px, 6vw, 40px) clamp(14px, 3vw, 22px);
    min-height: 0;
    background:
      linear-gradient(180deg,
        rgba(243, 240, 232, .35) 0%,
        rgba(243, 240, 232, .82) 42%,
        rgba(243, 240, 232, .94) 100%),
      url("assets/img/bg-image.png") left center / cover no-repeat,
      var(--paper-2);
    display: block;
  }
  .fragmenta__body { margin-left: 0; max-width: none; }
  .fragmenta__lead { font-size: 1.18rem; line-height: 1.8; letter-spacing: .08em; }
  .fragmenta__prose { font-size: 1rem; line-height: 2.05; letter-spacing: .04em; }
}

/* ============================================================
   Envoi — Colophon（旧 About + Quote + Contact 統合）
   背景画像＋紙の枠を踏襲しつつ、中の構造を 1 カラムで縦に流す
   ============================================================ */

.envoi {
  padding: clamp(12px, 2vw, 24px) var(--gutter) clamp(20px, 3vw, 36px);
  max-width: var(--maxw);
  margin: 0 auto;
}
.envoi__frame {
  position: relative;
  padding: clamp(20px, 2.6vw, 32px) clamp(24px, 4vw, 56px);
  background:
    linear-gradient(90deg,
      rgba(243, 240, 232, .96) 0%,
      rgba(243, 240, 232, .9)  30%,
      rgba(243, 240, 232, .6)  55%,
      rgba(243, 240, 232, .18) 78%,
      rgba(243, 240, 232, 0)   100%),
    url("assets/img/about_bg.png") right center / cover no-repeat,
    var(--paper-2);
  border: 1px solid var(--line-soft);
  overflow: hidden;
}
.envoi__body {
  position: relative;
  z-index: 1;
  max-width: 580px;
}

.envoi__epigraph {
  margin: 0 0 clamp(14px, 2vw, 22px);
}
.envoi__epigraph-text {
  display: inline-block;
  font-family: var(--serif-ja);
  font-weight: 500;
  font-size: clamp(1.2rem, 2.2vw, 1.6rem);
  letter-spacing: .14em;
  line-height: 1.6;
  color: var(--ink);
  background-image: linear-gradient(var(--ink-soft), var(--ink-soft));
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0 1px;
  transition: background-size .5s ease;
  padding-bottom: 4px;
}
.envoi__epigraph:hover .envoi__epigraph-text,
.envoi__epigraph-text:hover { background-size: 100% 1px; }

.envoi__head { margin: 0 0 clamp(14px, 2vw, 22px); }
.envoi__head .envoi__author-label { margin: 0 0 .6em; }
.envoi__head .envoi__author-name  { margin: 0; }

.envoi__prose {
  font-family: var(--serif-ja);
  font-size: .84rem;
  line-height: 1.8;
  letter-spacing: .08em;
  color: var(--ink-soft);
  margin: 0 0 clamp(12px, 2vw, 18px);
}

.envoi__links {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(20px, 3vw, 40px);
  align-items: baseline;
}
.envoi__link {
  font-family: var(--serif-ja);
  font-size: .92rem;
  letter-spacing: .12em;
  color: var(--ink-soft);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  padding-bottom: 3px;
  transition: color .2s ease, border-color .2s ease;
}
.envoi__link:hover { color: var(--ink); border-color: var(--ink); }
.envoi__link span {
  display: inline-block;
  margin-left: .4em;
  transition: transform .2s ease;
}
.envoi__link:hover span { transform: translateX(3px); }

.envoi__author {
  margin: clamp(10px, 1.5vw, 18px) 0 0;
  padding-bottom: clamp(20px, 3vw, 28px);
  border-bottom: 1px solid var(--line);
}
.envoi__author-label {
  font-family: var(--serif-en);
  font-size: .78rem;
  font-style: italic;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--muted, #7A7A7A);
  margin: 0 0 .8em;
}
.envoi__author-name {
  font-family: var(--serif-ja);
  font-size: 1rem;
  letter-spacing: .08em;
  color: var(--ink);
  margin: 0 0 1.1em;
}
.envoi__author-ids {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 22px;
}
.envoi__author-ids a {
  font-family: var(--serif-en);
  font-size: .85rem;
  letter-spacing: .08em;
  color: var(--ink-soft);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  padding-bottom: 2px;
  transition: color .2s ease, border-color .2s ease;
}
.envoi__author-ids a:hover { color: var(--ink); border-color: var(--ink); }

.envoi__contact {
  font-family: var(--serif-ja);
  font-size: .88rem;
  line-height: 1.8;
  letter-spacing: .08em;
  color: var(--ink-soft);
  margin: clamp(14px, 2vw, 22px) 0 0;
}
.envoi__contact .contact-mail,
.envoi__contact a {
  font-family: var(--serif-en);
  font-size: 1rem;
  letter-spacing: .06em;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  padding: 0 2px 2px;
  margin: 0 .15em;
  transition: border-color .2s ease;
}
.envoi__contact a:hover { border-color: var(--ink); }

.envoi__seal {
  position: relative;
  z-index: 1;
  margin: clamp(5px, 2vw, 5px) 0 0;
  text-align: center;
  font-family: var(--serif-en);
  font-style: italic;
  font-size: .74rem;
  letter-spacing: .42em;
  color: var(--ink-mute);
}
.envoi__seal::before,
.envoi__seal::after {
  content: "·";
  display: inline-block;
  margin: 0 1.2em;
  transform: translateY(-2px);
  color: var(--ink-mute);
  opacity: .6;
}

@media (max-width: 720px) {
  .envoi__frame {
    background:
      linear-gradient(180deg,
        rgba(243, 240, 232, .96) 0%,
        rgba(243, 240, 232, .86) 55%,
        rgba(243, 240, 232, .28) 100%),
      url("assets/img/about_bg.png") right bottom / 180% auto no-repeat,
      var(--paper-2);
  }
  .envoi__body { max-width: none; }
  .envoi__prose {
    font-size: calc(.84rem + 1px);
    line-height: 1.85;
  }
  .envoi__prose br { display: none; }
  .envoi__contact { line-height: 1.85; }
  .envoi__br-desktop { display: none; }
}

/* ============================================================
   Legal (Privacy Policy, etc.)
   ============================================================ */

.legal {
  padding: clamp(120px, 14vw, 180px) var(--gutter) clamp(40px, 6vw, 80px);
  max-width: 880px;
  margin: 0 auto;
}
.legal__head {
  display: flex;
  flex-direction: column;
  margin-bottom: clamp(32px, 5vw, 56px);
}
.legal__title {
  font-family: var(--serif-ja);
  font-weight: 500;
  font-size: clamp(1.6rem, 3.4vw, 2.2rem);
  letter-spacing: .2em;
  margin: 0;
  color: var(--ink);
}
.legal__en {
  font-family: var(--serif-en);
  font-size: .82rem;
  letter-spacing: .32em;
  color: var(--ink-mute);
  margin: .6em 0 0;
}
.legal__head .rule { margin-top: 22px; }
.legal__lead {
  font-size: .95rem;
  line-height: 2;
  color: var(--ink-soft);
  margin: 0 0 32px;
  letter-spacing: .04em;
}
.legal__h2 {
  font-family: var(--serif-ja);
  font-weight: 500;
  font-size: 1.05rem;
  letter-spacing: .12em;
  color: var(--ink);
  margin: 36px 0 14px;
}
.legal__p {
  font-size: .92rem;
  line-height: 2;
  color: var(--ink-soft);
  letter-spacing: .04em;
  margin: 0 0 14px;
}
.legal__list {
  font-size: .92rem;
  line-height: 2;
  color: var(--ink-soft);
  letter-spacing: .04em;
  margin: 0 0 14px;
  padding-left: 1.4em;
}
.legal__list li { margin-bottom: 4px; }
.legal__contact {
  font-family: var(--serif-en);
  font-size: 1rem;
  letter-spacing: .08em;
  margin: 8px 0 0;
}
.legal__contact a {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  padding-bottom: 2px;
  transition: border-color .2s ease;
}
.legal__contact a:hover { border-color: var(--ink); }
.legal__date {
  margin-top: 48px;
  font-size: .82rem;
  color: var(--ink-mute);
  letter-spacing: .08em;
}

/* ============================================================
   Footer
   ============================================================ */

.site-footer {
  border-top: 1px solid var(--line);
  padding: clamp(40px, 5vw, 64px) var(--gutter);
  max-width: var(--maxw);
  margin: 0 auto;
}
.site-footer__top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
  flex-wrap: wrap;
}
.footer-nav { display: flex; flex-wrap: wrap; gap: clamp(18px, 2.4vw, 38px); }
.footer-nav a {
  font-family: var(--serif-en);
  font-size: .82rem;
  letter-spacing: .2em;
  color: var(--ink-soft);
  transition: color .3s;
}
.footer-nav a:hover { color: var(--ink); }
.site-footer__bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid var(--line-soft);
  font-size: .72rem;
  letter-spacing: .18em;
  color: var(--ink-mute);
}
.site-footer__eq { font-family: var(--serif-en); font-style: italic; }
.site-footer__legal a {
  color: var(--ink-mute);
  text-decoration: none;
  transition: color .3s;
}
.site-footer__legal a:hover { color: var(--ink); }

/* ============================================================
   Responsive
   ============================================================ */

@media (max-width: 1024px) {
  .studies__grid { grid-template-columns: repeat(2, 1fr); }
  .studies__grid--two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .studies__grid--three { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .glossary__grid { grid-template-columns: repeat(3, 1fr); }
  .feature__media { max-width: 420px; }
}

@media (max-width: 820px) {
  .nav { gap: 26px; }
  .nav__ja { display: none; }
}

@media (max-width: 720px) {
  /* header padding adjusts on SP */
  .site-header {
    padding-top: clamp(16px, 4vw, 24px);
    padding-bottom: clamp(16px, 4vw, 24px);
  }

  /* header → hamburger */
  .nav {
    position: fixed;
    inset: 0 0 0 auto;
    width: min(78vw, 320px);
    flex-direction: column;
    justify-content: center;
    gap: 34px;
    padding: 0 40px;
    background: var(--paper-2);
    border-left: 1px solid var(--line);
    transform: translateX(100%);
    transition: transform .45s cubic-bezier(.5,.05,.2,1);
  }
  .nav a { flex-direction: row; align-items: baseline; gap: 14px; }
  .nav__ja { display: inline; }
  body.nav-open .nav { transform: translateX(0); }
  body.nav-open { overflow: hidden; }
  /* hamburger floats over the page — visible at any scroll position */
  .nav-toggle {
    display: flex;
    position: fixed;
    top: clamp(14px, 4vw, 22px);
    right: clamp(14px, 4vw, 22px);
    width: 46px;
    height: 46px;
    padding: 0;
    align-items: center;
    justify-content: center;
    gap: 5px;
    flex-direction: column;
    z-index: 60;
    background: rgba(245, 240, 232, 0.62);
    -webkit-backdrop-filter: saturate(140%) blur(12px);
    backdrop-filter: saturate(140%) blur(12px);
    border: 1px solid rgba(28, 24, 20, 0.08);
    border-radius: 50%;
    box-shadow: 0 1px 2px rgba(28, 24, 20, 0.04);
    transition: background .3s ease, border-color .3s ease, box-shadow .3s ease;
  }
  .nav-toggle span { width: 18px; }
  .nav-toggle span:nth-child(1) { width: 18px; }
  .nav-toggle span:nth-child(2) { width: 11px; }
  .nav-toggle span:nth-child(3) { width: 15px; }
  body.nav-open .nav-toggle {
    background: transparent;
    border-color: transparent;
    box-shadow: none;
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
  }
  body.nav-open .nav-toggle span:nth-child(1) { width: 20px; transform: translateY(6px) rotate(45deg); }
  body.nav-open .nav-toggle span:nth-child(2) { opacity: 0; }
  body.nav-open .nav-toggle span:nth-child(3) { width: 20px; transform: translateY(-6px) rotate(-45deg); }

  /* hero: SP — title above image, rest of text below */
  .hero {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    position: relative;
    min-height: 0;
    background: var(--paper);
    padding: 0;
    overflow: hidden;
  }
  .hero__bg {
    order: 1;
    display: block;
    position: relative;
    width: 100%;
    inset: auto;
    z-index: 0;
    margin: 0;
    height: auto;
    aspect-ratio: 1 / 1.6;
    overflow: hidden;
  }
  .hero__bg img {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center bottom;
    -webkit-mask-image: none;
    mask-image: none;
  }
  .hero__bg::before { content: none; }

  .hero__scrim { display: none; }
  .hero__scroll, .hero__side { display: none; }

  /* unwrap inner & text so individual items become direct flex children of .hero */
  .hero__inner { display: contents; }
  .hero__text { display: contents; }

  br.sp-only { display: inline; }
  br.pc-only { display: none; }

  /* series label — sits in flex flow just above the lead copy.
     EN と JA は同一行に並べ、タグラインのみ下段に折り返す。 */
  .hero__series {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    order: 2;
    padding: 0 var(--gutter);
    margin: clamp(20px, 5vw, 30px) 0 0;
    color: var(--ink);
    text-align: left;
    line-height: 1.4;
  }
  .hero__series-en {
    font-family: var(--serif-en);
    font-weight: 500;
    font-style: italic;
    font-size: 1.35rem;
    letter-spacing: .08em;
  }
  .hero__series-ja {
    position: relative;
    font-size: 1.05rem;
    letter-spacing: .2em;
    color: var(--ink-mute);
    margin-left: clamp(18px, 4.5vw, 26px);
  }
  .hero__series-ja::before {
    content: "";
    position: absolute;
    left: calc(clamp(18px, 4.5vw, 26px) / -2);
    top: 50%;
    width: 1px;
    height: 1em;
    background: currentColor;
    opacity: .35;
    transform: translate(-50%, -50%);
  }
  .hero__series-tagline {
    flex-basis: 100%;
    font-family: var(--serif-ja);
    font-size: .95rem;
    letter-spacing: .08em;
    color: var(--ink-soft);
    line-height: 1.7;
    margin-top: .85em;
  }

  /* title — overlaid on top of the image, below the header */
  .hero__title {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    z-index: 5;
    padding: calc(clamp(97px, 25.9vw, 134px) + 3.1em + 1.55em) var(--gutter) 0;
    margin: 0;
    transform: translateX(-10px);
    font-size: clamp(0.995rem, calc(3.52vw + 0.125rem), 1.235rem);
    color: var(--ink);
    line-height: 1.55;
    letter-spacing: .04em;
    text-align: left;
  }
  .hero__title span { display: block; white-space: nowrap; }

  /* Typewriter intro: pre-paint hide (FOUC guard). JS removes this class
     once it has cleared the title text and is ready to type. The title
     stays in its final (定位置) position the whole time — no centering,
     no fly-in, just a slow typewriter reveal at the natural spot. */
  .hero-anim-ready .hero__title { visibility: hidden; }

  /* Blinking caret rendered during typing. JS removes the node when done.
     Note: must out-specify `.hero__title span { display: block }` above —
     the cursor is a nested <span>, so without `.hero__title` qualifier
     the `display: inline-block` is overridden and the caret breaks to a
     new line. */
  .hero__title .hero__title-cursor {
    display: inline-block;
    width: 1.5px;
    height: 1em;
    margin-left: 0.08em;
    background: currentColor;
    vertical-align: -0.12em;
    animation: hero-blink 1s steps(2, jump-none) infinite;
  }
  @keyframes hero-blink {
    0%, 50% { opacity: 1; }
    50.01%, 100% { opacity: 0; }
  }

  /* below image: rule, leads, btn */
  .hero__text .rule {
    order: 2;
    margin: clamp(28px, 7vw, 44px) var(--gutter) 0;
  }
  .hero__lead {
    order: 2;
    font-size: 1rem;
    line-height: 1.75;
    margin: 22px 0 0;
    padding: 0 var(--gutter);
    letter-spacing: .02em;
    text-align: left;
    white-space: normal;
  }
  /* keep paragraphs packed together — line breaks already in markup */
  .hero__text .hero__lead + .hero__lead { margin-top: .4em; }

  /* button → text link on SP */
  .hero .btn {
    order: 2;
    border: 0;
    padding: 0;
    margin: 28px var(--gutter) 0;
    gap: 18px;
    font-size: .7rem;
    letter-spacing: .18em;
    background: transparent;
    position: relative;
    display: inline-flex;
    align-self: flex-start;
  }
  .hero .btn::after {
    content: "";
    position: absolute;
    left: 0;
    right: 40px;
    bottom: -8px;
    height: 1px;
    background: var(--ink);
    opacity: .55;
  }
  .hero .btn:hover { background: transparent; color: var(--ink); }

  /* Z = D + iD — centered below the text block */
  .hero__eq {
    order: 3;
    display: block;
    position: relative;
    inset: auto;
    z-index: 1;
    text-align: center;
    font-family: var(--serif-en);
    font-style: italic;
    font-size: .95rem;
    letter-spacing: .14em;
    color: var(--ink-soft);
    margin: clamp(28px, 7vw, 44px) 0 clamp(24px, 6vw, 36px);
  }

  /* next section: rounded top + SCROLL indicator */
  .cats {
    position: relative;
    background: var(--paper-2);
    border-top: 0;
    border-radius: 28px 28px 0 0;
    margin-top: 0;
    padding-top: 10px;
    padding-left: 0;
    padding-right: 0;
  }
  .cats::before {
    content: "";
    position: absolute;
    top: 38px;
    left: 50%;
    transform: translateX(-50%);
    font-family: var(--serif-en);
    font-size: .72rem;
    letter-spacing: .42em;
    color: var(--ink-mute);
  }
  .cats::after {
    content: "";
    position: absolute;
    top: 62px;
    left: 50%;
    transform: translateX(-50%);
    width: 1px;
    height: 22px;
    background: var(--line);
  }
  .cat {
    grid-template-columns: 1fr;
    grid-template-areas:
      "icon"
      "label"
      "desc";
    justify-items: center;
    text-align: center;
    column-gap: 0;
    row-gap: 8px;
    padding: 24px 2px 22px;
  }
  .cat + .cat::before { top: 14%; bottom: 14%; }
  .cat__icon img { width: 40px; height: 40px; }
  .cat__label { align-items: center; gap: 4px; }
  .cat__label b {
    font-size: .9625rem;
    letter-spacing: .06em;
    white-space: nowrap;
  }
  .cat__label small {
    font-size: .7225rem;
    letter-spacing: .12em;
    white-space: nowrap;
  }
  .cat__desc { display: none; }

  /* STUDIES: editorial hairline list (thumb left + text right) */
  .studies__grid,
  .studies__grid--two,
  .studies__grid--three {
    display: flex;
    flex-direction: column;
    grid-template-columns: none;
    gap: 0;
    overflow: visible;
    margin: 0;
    padding: 0;
    border-top: 0.5px solid var(--line);
  }
  .studies__grid .card {
    background: transparent;
    border: 0;
    border-bottom: 0.5px solid var(--line);
    border-radius: 0;
    padding: 0;
    min-height: 0;
  }
  .studies__grid .card a {
    display: grid;
    grid-template-columns: 78px minmax(0, 1fr);
    grid-template-rows: auto auto auto;
    column-gap: 20px;
    align-items: start;
    height: auto;
    padding: 26px 4px;
    transition: background-color .2s ease;
  }
  .studies__grid .card a:hover,
  .studies__grid .card a:active,
  .studies__grid .card a:focus-visible {
    background-color: rgba(32, 29, 24, 0.04);
    transform: none;
  }
  .studies__grid .card__no,
  .studies__grid .card__cat,
  .studies__grid .card__desc,
  .studies__grid .card__foot,
  .studies__grid .card__arrow { display: none; }
  .studies__grid .card__thumb {
    grid-column: 1;
    grid-row: 1 / 4;
    width: 78px;
    height: 78px;
    aspect-ratio: 1 / 1;
    margin: 0;
    border: 0;
    border-radius: 0;
    overflow: hidden;
    flex-shrink: 0;
  }
  .studies__grid .card__thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    mix-blend-mode: normal;
  }
  .studies__grid .card__date {
    grid-column: 2;
    grid-row: 1;
    min-width: 0;
    margin: 0;
    font-family: var(--serif-en);
    font-size: 14px;
    line-height: 1;
    letter-spacing: 0.22em;
    color: var(--ink-mute);
  }
  .studies__grid .card__title {
    grid-column: 2;
    grid-row: 2;
    min-width: 0;
    margin: 6px 0 4px;
    font-family: var(--serif-ja);
    font-weight: 500;
    font-size: 19px;
    line-height: 1.4;
    letter-spacing: .03em;
    color: var(--ink);
  }
  .studies__grid .card__subtitle {
    grid-column: 2;
    grid-row: 3;
    min-width: 0;
    margin: 0;
    font-family: var(--serif-ja);
    font-size: 13px;
    line-height: 1.65;
    color: var(--ink-soft);
  }
  /* NEWS: timeline — stacked date over content */
  .news__head { flex-direction: column; align-items: flex-start; gap: 14px; }
  .news__timeline { margin-left: 14px; }
  .news-item__link { padding: 22px 0 22px 22px; }
  .news-item__link::before { top: 32px; }
  .news-item__date {
    position: static;
    display: block;
    width: auto;
    padding: 0;
    text-align: left;
    font-size: 1.2rem;
    margin-bottom: 8px;
  }
  .news-item__title { font-size: 1rem; line-height: 1.55; }
  .news-item__subtitle { display: block; margin-left: 0; font-size: .82rem; margin-top: 4px; }
  /* LEARN: drop the carousel for a 2×2 grid of the latest 4. The carousel
     JS still binds (harmless: track no longer scrolls horizontally, nav
     buttons are hidden), and PC keeps the original horizontal swipe deck. */
  .learn__carousel {
    width: auto;
    margin-left: 0;
  }
  .learn__grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
    overflow: visible;
    scroll-snap-type: none;
    scroll-padding-left: 0;
    padding: 0;
  }
  .learn .card {
    flex: initial;
    scroll-snap-align: none;
    min-height: 44px;
  }
  /* Show only the first 4 (latest, since they're already in date-desc
     order in the HTML). Items 5+ stay in the DOM but are hidden — they
     remain crawlable, and PC continues to show all of them. */
  .learn__grid > .card:nth-child(n+5) { display: none; }
  .learn__nav { display: none; }
  /* Move the "see all" link to the bottom: hide the head copy, show the
     bottom copy below the grid. */
  .learn__head .text-link { display: none; }
  .learn__more--bottom {
    display: inline-flex;
    align-self: flex-start;
    margin-top: 22px;
    min-height: 44px;
    align-items: center;
  }
  /* KEY CONCEPTS: replace tab UI with static dictionary showcase on narrow screens */
  .glossary__grid { display: none; }
  .glossary__head .text-link { display: none; }

  .kc-dict {
    display: block;
    border: 0.5px solid var(--line-soft);
    padding: 0 18px;
  }
  .kc-dict__list {
    list-style: none;
    margin: 0;
    padding: 0;
  }
  .kc-dict__item + .kc-dict__item .kc-dict__row {
    border-top: 0.5px solid var(--line-soft);
  }
  .kc-dict__row {
    display: block;
    padding: 14px 0;
    color: inherit;
    text-decoration: none;
    transition: opacity .2s;
  }
  .kc-dict__row:active { opacity: .55; }
  .kc-dict__head {
    display: flex;
    align-items: baseline;
    gap: 9px;
    min-width: 0;
  }
  .kc-dict__ja {
    font-family: var(--serif-ja);
    font-weight: 600;
    font-size: 18px;
    letter-spacing: .04em;
    color: var(--ink);
    white-space: nowrap;
  }
  .kc-dict__yomi {
    font-size: 9px;
    letter-spacing: .06em;
    color: var(--ink-mute);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    min-width: 0;
    flex: 0 1 auto;
  }
  .kc-dict__en {
    margin-left: auto;
    font-family: var(--serif-en);
    font-size: 9px;
    letter-spacing: .12em;
    color: var(--ink-mute);
    text-transform: uppercase;
    white-space: nowrap;
    flex: 0 0 auto;
  }
  .kc-dict__desc {
    display: block;
    margin-top: 7px;
    font-family: var(--serif-ja);
    font-size: 14px;
    line-height: 1.75;
    letter-spacing: .03em;
    color: var(--ink-soft);
  }
  .kc-dict__more {
    display: block;
    border-top: 0.5px solid var(--line-soft);
    padding: 15px 0;
    text-align: center;
    font-family: var(--serif-ja);
    font-size: 11px;
    letter-spacing: .15em;
    color: var(--ink);
    text-decoration: none;
    transition: opacity .2s;
  }
  .kc-dict__more:active { opacity: .55; }
  .kc-dict__more span { margin-left: 4px; }
  .studies__head { flex-direction: column; align-items: flex-start; gap: 14px; }
  .learn__head { flex-direction: column; align-items: flex-start; gap: 14px; }
  .glossary__head { flex-direction: column; align-items: flex-start; gap: 14px; }

  /* volumes: stack rows into cards */
  .volumes__head { flex-direction: column; align-items: flex-start; gap: 14px; }
  .volumes__row--head { display: none; }
  .volumes__row {
    grid-template-columns: 1fr;
    gap: 12px;
    padding: 24px 0;
  }
  .volumes__no { flex-direction: row; align-items: baseline; gap: 12px; }
  .volumes__no-en { font-size: 1.28rem; }
  .volumes__no-ja { letter-spacing: .18em; font-size: .82rem; }
  .volumes__date { font-size: .94rem; }
  .volumes__title-ja { font-size: 1.08rem; }
  .volumes__title-en { font-size: .88rem; }
  .volumes__doi { font-size: .88rem; word-break: break-all; }
  .volumes__journal-en { font-size: 1.2rem; }
  .volumes__journal-ja { font-size: .92rem; }
  .volumes__meta-row { grid-template-columns: 1fr; gap: 4px; }
  .volumes__meta-row dt { flex-direction: row; align-items: baseline; gap: 8px; font-size: .88rem; }
  .volumes__meta-row dt small { font-size: .76rem; }
  .volumes__meta-row dd { font-size: .98rem; }
  .volumes__issn-slot { font-size: 1.04rem; }

  .archive__list a { flex-direction: column; gap: 4px; }
  .archive__ja { white-space: normal; }
  .archive__foot { flex-direction: column; }

  .quote__inner { grid-template-columns: 1fr; text-align: left; }
  .quote__sigil { display: none; }

  .about__inner {
    grid-template-columns: 1fr;
    gap: 28px;
  }
  .about__sigil { justify-self: start; }

  .brand__en { font-size: .9rem; letter-spacing: .18em; }
  .brand__ja { font-size: .68rem; letter-spacing: .34em; }
  .brand__mark { font-size: 1.9rem; }
  /* reserve space on the right for the floating hamburger so the brand name doesn't collide */
  .site-header .brand { padding-right: 62px; }

  /* ---- SP global text size bump ---- */
  .section-title { font-size: clamp(2rem, 6vw, 2.4rem); }
  .section-sub { font-size: .96rem; letter-spacing: .3em; }
  .text-link { font-size: 1rem; letter-spacing: .16em; }

  .learn__lead { font-size: 1rem; line-height: 1.95; }
  .glossary__lead { font-size: 1rem; line-height: 1.95; }

  .learn .card__title { font-size: 1.06rem; margin: 10px 0 10px; }
  .learn .card__desc { font-size: .88rem; line-height: 1.85; }
  .learn .card__cat { font-size: .945rem; }
  .learn .card__foot time { font-size: .82rem; }

  .feature__eyebrow { font-size: .88rem; letter-spacing: .2em; }
  .feature__volume { font-size: 1rem; letter-spacing: .26em; }
  .feature__title { font-size: clamp(1.7rem, 5.4vw, 2.1rem); line-height: 1.3; letter-spacing: .04em; }
  .feature__subtitle { font-size: 1.28rem; line-height: 1.55; letter-spacing: .04em; }
  .feature__title-row { gap: 4px 12px; }
  .feature__text { font-size: 1.075rem; line-height: 2.05; }
  .feature__text--en { font-size: 1.075rem; }
  .study-meta { height: auto; justify-content: flex-start; }
  .study-meta dt { font-size: .82rem; letter-spacing: .28em; }
  .study-meta dd { font-size: 1.04rem; }
  .study-link { font-size: .9rem; }
  .study-group__label { font-size: .88rem; }
  .study-group a { font-size: .92rem; }

  /* ---- Mobile-only abstract teaser shown above the toggle ---- */
  .feature__summary {
    display: block;
    margin: 18px 0 18px;
    font-family: var(--serif-ja);
    font-size: 1.04rem;
    line-height: 2.05;
    letter-spacing: .02em;
    color: var(--ink-soft);
  }

  /* ---- Accordion (mobile only) — details collapsible per volume ---- */
  .feature__toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: .6em;
    align-self: flex-start;
    margin: 4px 0 0;
    padding: 12px 22px;
    min-height: 44px;
    font-family: var(--serif-ja);
    font-size: .95rem;
    letter-spacing: .12em;
    color: var(--ink-soft);
    background: transparent;
    border: 1px solid var(--line);
    border-radius: 999px;
    cursor: pointer;
    transition: background .25s, color .25s, border-color .25s;
    -webkit-appearance: none;
            appearance: none;
  }
  .feature__toggle:hover,
  .feature__toggle:focus-visible {
    background: var(--paper-2);
    color: var(--ink);
    border-color: var(--ink-soft);
  }
  .feature__toggle-text::before { content: attr(data-closed); }
  .feature__toggle[aria-expanded="true"] .feature__toggle-text::before { content: attr(data-open); }
  /* Hide the original text node — only the ::before content is shown. */
  .feature__toggle-text { font-size: 0; line-height: 1; }
  .feature__toggle-text::before { font-size: .95rem; }
  .feature__toggle-icon {
    width: 10px;
    height: 10px;
    border-right: 1.5px solid currentColor;
    border-bottom: 1.5px solid currentColor;
    transform: translateY(-2px) rotate(45deg);
    transition: transform .3s ease;
  }
  .feature__toggle[aria-expanded="true"] .feature__toggle-icon {
    transform: translateY(2px) rotate(-135deg);
  }

  .feature__collapse {
    max-height: 0;
    overflow: hidden;
    transition: max-height .35s ease;
    width: 100%;
  }
  .feature__collapse.is-open {
    max-height: var(--collapse-h, 5000px);
  }

  .about__title { font-size: clamp(1.9rem, 6.4vw, 2.4rem); letter-spacing: .38em; }
  .about__en { font-size: .9rem; letter-spacing: .26em; }
  .about__text { font-size: 1.04rem; line-height: 2; }
  .about__sigil i { font-size: 1.05rem; }

  .quote__brand { font-size: .92rem; letter-spacing: .22em; }
  .quote__lead { font-size: clamp(1.5rem, 5.6vw, 2.05rem); line-height: 1.7; }
  .quote__sub { font-size: .96rem; line-height: 2; }

  .site-footer__top { justify-content: flex-start; text-align: left; }
  .site-footer .footer-nav,
  .site-footer__bottom { display: none; }

  /* mobile menu links — larger tap targets */
  .nav__en { font-size: 1.04rem; letter-spacing: .2em; }
  .nav__ja { font-size: .82rem; letter-spacing: .24em; }
}

@media (max-width: 420px) {
  .cat__desc { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}