:root {
  --ink: #181512;
  --muted: #625e59;
  --paper: #eef1f0;
  --paper-deep: #dfe5e4;
  --milk: #fffaf0;
  --crust: #421d13;
  --crust-light: #7a3c22;
  --honey: #e0a019;
  --honey-light: #ffd76b;
  --steel: #859295;
  --line: rgba(24, 21, 18, 0.17);
  --serif: "Yu Mincho", "Hiragino Mincho ProN", "BIZ UDPMincho", serif;
  --sans: "Yu Gothic", "Hiragino Kaku Gothic ProN", "BIZ UDPGothic", sans-serif;
  --number: Bahnschrift, "Arial Narrow", sans-serif;
  --content: 740px;
  --wide: 1180px;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 92px;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    linear-gradient(90deg, transparent 49.9%, rgba(24, 21, 18, 0.025) 50%, transparent 50.1%),
    var(--paper);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.95;
  letter-spacing: 0.02em;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; display: block; }
a { color: inherit; }

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 100;
  padding: 8px 14px;
  background: var(--ink);
  color: white;
  transform: translateY(-150%);
}
.skip-link:focus { transform: translateY(0); }

.reading-progress {
  position: fixed;
  inset: 0 0 auto;
  z-index: 90;
  height: 3px;
  background: rgba(255, 255, 255, 0.15);
}
.reading-progress span {
  display: block;
  width: 0;
  height: 100%;
  background: var(--honey);
}

.site-header {
  width: min(calc(100% - 40px), var(--wide));
  height: 74px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}
.site-name,
.header-jump {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
}
.site-mark { color: var(--honey); font-size: 22px; line-height: 1; }
.header-jump { border-bottom: 1px solid currentColor; }

.hero {
  width: min(calc(100% - 40px), var(--wide));
  min-height: min(760px, calc(100vh - 74px));
  margin: 0 auto;
  padding: 58px 0 72px;
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(420px, 1.08fr);
  gap: 6vw;
  align-items: center;
}
.eyebrow,
.section-kicker,
.toc-label {
  margin: 0 0 20px;
  color: var(--crust-light);
  font-family: var(--number);
  font-size: 11px;
  font-weight: 700;
  line-height: 1.4;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}
.hero h1 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(42px, 5.6vw, 82px);
  font-weight: 600;
  line-height: 1.18;
  letter-spacing: -0.055em;
}
.hero h1 em { color: var(--crust); font-style: normal; }
.hero-lead {
  max-width: 31em;
  margin: 28px 0 34px;
  color: var(--muted);
  font-size: 15px;
}

.conversion {
  position: relative;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 15px;
  align-items: center;
  padding: 22px 24px 18px;
  background: var(--crust);
  color: white;
  box-shadow: 12px 12px 0 var(--honey);
  transform: rotate(-1deg);
}
.conversion > div span { display: block; font-size: 11px; opacity: 0.72; }
.conversion strong {
  font-family: var(--number);
  font-size: clamp(38px, 4vw, 60px);
  line-height: 1;
  letter-spacing: -0.04em;
}
.conversion small { margin-left: 3px; font-size: 0.34em; letter-spacing: 0; }
.conversion-arrow { color: var(--honey-light); font-size: 28px; }
.conversion p {
  grid-column: 1 / -1;
  margin: 10px 0 0;
  padding-top: 12px;
  border-top: 1px solid rgba(255,255,255,0.25);
  font-size: 12px;
  line-height: 1.5;
}
.conversion p strong { font-size: 15px; color: var(--honey-light); }

.hero-visual { position: relative; margin: 0; }
.hero-visual::before {
  content: "80 → 70";
  position: absolute;
  z-index: 2;
  top: -24px;
  right: -12px;
  width: 92px;
  height: 92px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--honey);
  color: var(--crust);
  font-family: var(--number);
  font-weight: 800;
  letter-spacing: -0.04em;
  box-shadow: 0 8px 30px rgba(66, 29, 19, 0.2);
}
.hero-visual img {
  width: 100%;
  aspect-ratio: 4 / 5;
  object-fit: cover;
  clip-path: polygon(0 4%, 94% 0, 100% 96%, 6% 100%);
  filter: saturate(0.92) contrast(1.03);
}
.hero-visual figcaption {
  width: 74%;
  margin: -22px 0 0 auto;
  padding: 16px 18px;
  position: relative;
  background: var(--milk);
  border-left: 5px solid var(--honey);
  font-family: var(--serif);
  font-size: 14px;
  line-height: 1.6;
}

.story-opening {
  padding: 92px max(20px, calc((100% - var(--content)) / 2));
  background: var(--crust);
  color: white;
  font-family: var(--serif);
  font-size: clamp(21px, 2.5vw, 30px);
  line-height: 1.9;
}
.story-opening p { margin: 0; }
.story-opening p + p { margin-top: 1.3em; }
.story-opening p:first-child { color: var(--honey-light); }

.article-layout {
  width: min(calc(100% - 40px), var(--wide));
  margin: 0 auto;
  display: grid;
  grid-template-columns: 210px minmax(0, var(--content));
  gap: min(9vw, 110px);
  justify-content: center;
}
.toc {
  position: sticky;
  top: 34px;
  align-self: start;
  margin-top: 110px;
  padding-top: 16px;
  border-top: 3px solid var(--ink);
}
.toc-label { margin-bottom: 14px; color: var(--muted); }
.toc nav { display: grid; }
.toc a {
  padding: 8px 0;
  color: var(--muted);
  text-decoration: none;
  font-size: 12px;
  line-height: 1.4;
  border-bottom: 1px solid var(--line);
}
.toc a:hover,
.toc a:focus-visible { color: var(--crust); padding-left: 5px; }

.article-body { min-width: 0; }
.article-section {
  padding: 108px 0;
  border-bottom: 1px solid var(--line);
}
.article-section h2 {
  margin: 0 0 38px;
  font-family: var(--serif);
  font-size: clamp(32px, 4vw, 52px);
  font-weight: 600;
  line-height: 1.38;
  letter-spacing: -0.045em;
}
.article-section > p { margin: 0 0 1.45em; }
.article-section strong { color: var(--crust); }
.section-kicker { display: flex; align-items: center; gap: 12px; }
.section-kicker::after { content: ""; width: 34px; height: 1px; background: currentColor; }
.quiet { color: var(--muted); font-size: 14px; }

.note-box {
  margin-top: 40px;
  padding: 24px 28px;
  background: var(--milk);
  border: 1px solid rgba(224, 160, 25, 0.48);
  box-shadow: 7px 7px 0 rgba(224, 160, 25, 0.22);
}
.note-box span {
  display: block;
  margin-bottom: 8px;
  color: var(--crust-light);
  font-family: var(--number);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.16em;
}
.note-box p { margin: 0; font-size: 15px; }

.term-intro {
  margin: 0 0 30px;
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 18px;
  align-items: center;
}
.term {
  padding: 5px 11px 4px;
  background: var(--ink);
  color: white;
  font-family: var(--serif);
  font-size: 18px;
  font-weight: 700;
  line-height: 1.5;
}
.term-intro p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.7; }

.mini-equation {
  margin: 42px 0;
  padding: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  background: var(--paper-deep);
  font-family: var(--number);
}
.mini-equation span { font-size: 24px; }
.mini-equation i { color: var(--steel); font-style: normal; }
.mini-equation strong { font-size: 27px; color: var(--crust); }

blockquote {
  margin: 38px 0;
  padding: 6px 0 6px 28px;
  border-left: 7px solid var(--honey);
  font-family: var(--serif);
  font-size: 23px;
  line-height: 1.7;
}
blockquote p { margin: 0; }

.split-section { display: grid; grid-template-columns: 1fr 250px; gap: 36px; }
.split-section .wide-note { grid-column: 1 / -1; }
.toast-card {
  align-self: center;
  padding: 24px;
  background: var(--milk);
  border: 1px solid var(--line);
}
.toast-card p { margin: 18px 0 0; font-size: 13px; line-height: 1.7; }
.toast-scale { display: grid; grid-template-columns: repeat(4, 1fr); gap: 5px; }
.toast-scale span { aspect-ratio: 1; border: 1px solid rgba(24,21,18,.12); }
.toast-scale span:nth-child(1) { background: #ead6a5; }
.toast-scale span:nth-child(2) { background: #c27a2e; }
.toast-scale span:nth-child(3) { background: #713818; }
.toast-scale span:nth-child(4) { background: #24110c; }

.tug-of-war {
  margin: 42px 0;
  display: grid;
  grid-template-columns: 1fr 100px 1fr;
  align-items: center;
  text-align: center;
}
.tug-of-war span {
  padding: 18px 10px;
  background: var(--milk);
  border: 1px solid var(--line);
  font-weight: 700;
  line-height: 1.45;
}
.tug-of-war small { color: var(--muted); font-weight: 500; }
.tug-of-war i { height: 3px; background: var(--crust-light); position: relative; }
.tug-of-war i::before,
.tug-of-war i::after { content: ""; position: absolute; top: 50%; width: 10px; height: 10px; border: 2px solid var(--crust-light); border-radius: 50%; transform: translateY(-50%); }
.tug-of-war i::before { left: -1px; }
.tug-of-war i::after { right: -1px; }

.recipe-section {
  margin-left: -50px;
  margin-right: -50px;
  padding: 78px 50px;
  background: var(--milk);
  border: 1px solid var(--line);
  box-shadow: 14px 14px 0 var(--crust);
}
.recipe-heading { display: flex; align-items: end; justify-content: space-between; gap: 20px; }
.recipe-purpose { max-width: 180px; color: var(--muted); font-size: 13px; }
.recipe-grid { display: grid; grid-template-columns: 0.85fr 1.3fr; gap: 48px; }
.recipe-grid h3 { margin: 0 0 18px; font-family: var(--serif); font-size: 23px; }
.ingredients dl { margin: 0; border-top: 2px solid var(--ink); }
.ingredients dl div { display: flex; justify-content: space-between; gap: 15px; padding: 11px 4px; border-bottom: 1px solid var(--line); }
.ingredients dt,
.ingredients dd { margin: 0; }
.ingredients dd { font-family: var(--number); font-weight: 700; }
.ingredients .highlight { color: var(--crust); background: rgba(224, 160, 25, 0.15); padding-inline: 10px; }
.ingredients > p { margin-top: 18px; color: var(--muted); font-size: 12px; line-height: 1.7; }
.method ol { margin: 0; padding: 0; list-style: none; border-top: 2px solid var(--ink); }
.method li { display: grid; grid-template-columns: 34px 1fr; gap: 12px; padding: 12px 0; border-bottom: 1px solid var(--line); }
.method li span { color: var(--crust-light); font-family: var(--number); font-size: 12px; font-weight: 700; }
.method li p { margin: 0; font-size: 14px; line-height: 1.7; }
.safety-box { margin-top: 44px; padding: 24px; background: var(--paper-deep); border-left: 6px solid var(--crust); }
.safety-box strong { display: block; margin-bottom: 8px; }
.safety-box p { margin: 0; font-size: 13px; line-height: 1.7; }
.safety-box p + p { margin-top: 10px; }

.caution-list { display: grid; grid-template-columns: repeat(3, 1fr); border: 1px solid var(--line); }
.caution-list article { padding: 24px 20px; }
.caution-list article + article { border-left: 1px solid var(--line); }
.caution-list span { color: var(--crust-light); font-family: var(--number); font-size: 11px; font-weight: 700; }
.caution-list h3 { min-height: 3.2em; margin: 12px 0; font-family: var(--serif); font-size: 17px; line-height: 1.6; }
.caution-list p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.7; }

.choice-table { display: grid; grid-template-columns: repeat(3, 1fr); margin: 40px 0; border: 1px solid var(--line); }
.choice-table > div { padding: 22px; }
.choice-table > div + div { border-left: 1px solid var(--line); }
.choice-table span { font-size: 11px; color: var(--muted); }
.choice-table strong { display: block; margin: 5px 0 10px; font-family: var(--number); font-size: 31px; }
.choice-table p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.7; }
.choice-table .recommended { background: var(--crust); color: white; transform: scale(1.04); box-shadow: 0 10px 25px rgba(66,29,19,.18); }
.choice-table .recommended strong,
.choice-table .recommended span,
.choice-table .recommended p { color: white; }
.closing-line { margin-top: 40px !important; font-family: var(--serif); font-size: 24px; }

.references-section ol { padding-left: 1.5em; }
.references-section li { padding: 7px 0; color: var(--muted); font-size: 13px; line-height: 1.6; overflow-wrap: anywhere; }
.references-section a { text-decoration-color: var(--honey); text-underline-offset: 4px; }
.references-section a:hover { color: var(--crust); }
.disclaimer { margin-top: 34px !important; padding-top: 24px; border-top: 1px solid var(--line); color: var(--muted); font-size: 12px; line-height: 1.7; }

.site-footer {
  width: min(calc(100% - 40px), var(--wide));
  margin: 0 auto;
  padding: 42px 0;
  display: flex;
  justify-content: space-between;
  border-top: 1px solid var(--line);
  font-size: 12px;
}
.site-footer p { margin: 0; font-weight: 700; }

:focus-visible { outline: 3px solid var(--honey); outline-offset: 4px; }

@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; padding-top: 42px; }
  .hero-copy { max-width: 680px; }
  .hero-visual { width: min(680px, 100%); }
  .hero-visual img { aspect-ratio: 5 / 4; }
  .article-layout { grid-template-columns: minmax(0, var(--content)); }
  .toc { display: none; }
}

@media (max-width: 680px) {
  body { font-size: 16px; line-height: 1.9; }
  .site-header { width: min(calc(100% - 28px), var(--wide)); height: 64px; }
  .hero { width: min(calc(100% - 28px), var(--wide)); min-height: auto; padding: 42px 0 60px; gap: 64px; }
  .hero h1 { font-size: clamp(37px, 11.5vw, 54px); }
  .conversion { grid-template-columns: 1fr auto 1fr; padding: 18px; box-shadow: 7px 7px 0 var(--honey); }
  .conversion strong { font-size: 40px; }
  .hero-visual::before { width: 74px; height: 74px; font-size: 14px; }
  .hero-visual img { aspect-ratio: 4 / 5; }
  .hero-visual figcaption { width: 88%; }
  .story-opening { padding-block: 68px; font-size: 20px; }
  .article-layout { width: min(calc(100% - 36px), var(--wide)); }
  .article-section { padding: 78px 0; }
  .article-section h2 { margin-bottom: 28px; font-size: 31px; }
  .term-intro { grid-template-columns: 1fr; gap: 10px; }
  .term { width: fit-content; }
  .mini-equation { flex-wrap: wrap; gap: 9px; padding: 18px 12px; }
  .mini-equation span { font-size: 19px; }
  .mini-equation strong { width: 100%; text-align: center; font-size: 24px; }
  blockquote { font-size: 20px; }
  .split-section { grid-template-columns: 1fr; }
  .split-section .wide-note { grid-column: auto; }
  .tug-of-war { grid-template-columns: 1fr 54px 1fr; }
  .tug-of-war span { padding: 14px 5px; font-size: 13px; }
  .recipe-section { margin-left: -8px; margin-right: -8px; padding: 48px 22px; box-shadow: 7px 7px 0 var(--crust); }
  .recipe-heading { align-items: start; flex-direction: column; }
  .recipe-grid { grid-template-columns: 1fr; gap: 38px; }
  .caution-list,
  .choice-table { grid-template-columns: 1fr; }
  .caution-list article + article,
  .choice-table > div + div { border-left: 0; border-top: 1px solid var(--line); }
  .caution-list h3 { min-height: 0; }
  .choice-table .recommended { transform: none; }
  .site-footer { width: min(calc(100% - 28px), var(--wide)); }
}

@media (prefers-reduced-motion: no-preference) {
  .hero-copy,
  .hero-visual { animation: arrive 700ms cubic-bezier(.2,.8,.2,1) both; }
  .hero-visual { animation-delay: 120ms; }
  @keyframes arrive {
    from { opacity: 0; transform: translateY(16px); }
    to { opacity: 1; transform: translateY(0); }
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}