:root {
  --paper: #f7f3eb;
  --paper-deep: #eee7da;
  --ink: #18201e;
  --muted: #636a66;
  --line: #cbc6ba;
  --white: #fffefa;
  --forest: #173f35;
  --with: #e86b45;
  --with-soft: #fff0e9;
  --about: #2f6db5;
  --about-soft: #eaf3ff;
  --from: #6c58a4;
  --from-soft: #f1edff;
  --by: #2b8b68;
  --by-soft: #e9f6f0;
  --on: #b87d18;
  --on-soft: #fff5dd;
  --radius-lg: 30px;
  --radius-md: 20px;
  --shadow: 0 22px 60px rgba(34, 45, 41, 0.1);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Hiragino Sans", "Yu Gothic", "YuGothic", "Noto Sans JP", sans-serif;
  font-feature-settings: "palt";
  line-height: 1.8;
}

a {
  color: inherit;
}

button,
summary {
  font: inherit;
}

code {
  padding: 0.1em 0.36em;
  border: 1px solid rgba(24, 32, 30, 0.13);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.62);
  color: inherit;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.88em;
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 12px;
  left: 12px;
  padding: 10px 16px;
  transform: translateY(-150%);
  border-radius: 8px;
  color: white;
  background: var(--ink);
}

.skip-link:focus {
  transform: none;
}

.site-header {
  position: sticky;
  z-index: 20;
  top: 0;
  display: flex;
  min-height: 68px;
  align-items: center;
  justify-content: space-between;
  padding: 0 5vw;
  border-bottom: 1px solid rgba(24, 32, 30, 0.12);
  background: rgba(247, 243, 235, 0.9);
  backdrop-filter: blur(14px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.03em;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 10px;
  color: white;
  background: var(--forest);
  font-family: Georgia, serif;
  font-weight: 400;
}

.section-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.section-nav a {
  color: #4d5652;
  font-size: 12px;
  font-weight: 700;
  text-decoration: none;
}

.section-nav a:hover,
.section-nav a:focus-visible {
  color: var(--with);
}

.hero {
  display: grid;
  min-height: calc(100vh - 68px);
  max-width: 1240px;
  margin: 0 auto;
  padding: clamp(70px, 10vw, 140px) 5vw 100px;
  grid-template-columns: minmax(0, 0.9fr) minmax(420px, 1.1fr);
  gap: clamp(60px, 8vw, 120px);
  align-items: center;
}

.eyebrow,
.section-number {
  margin: 0 0 22px;
  color: #68706c;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.16em;
}

.eyebrow span {
  display: inline-block;
  margin-right: 10px;
  padding: 4px 8px;
  border-radius: 99px;
  color: white;
  background: var(--forest);
  letter-spacing: 0.08em;
}

.hero h1,
.section-heading h2,
.closing-section h2 {
  margin: 0;
  font-family: "Yu Mincho", "Hiragino Mincho ProN", Georgia, serif;
  font-weight: 600;
  letter-spacing: -0.045em;
  line-height: 1.24;
}

.hero h1 {
  font-size: clamp(43px, 5.2vw, 76px);
}

.hero h1 em {
  position: relative;
  color: var(--with);
  font-style: normal;
}

.hero h1 em::after {
  position: absolute;
  right: 0;
  bottom: -7px;
  left: 0;
  height: 7px;
  border-radius: 50%;
  background: var(--with);
  content: "";
  opacity: 0.22;
}

.hero-lead {
  margin: 32px 0;
  color: #4d5652;
  font-size: clamp(16px, 1.5vw, 19px);
  line-height: 2;
}

.hero-lead b {
  color: var(--ink);
}

.primary-cta {
  display: inline-flex;
  min-height: 56px;
  align-items: center;
  gap: 28px;
  justify-content: space-between;
  padding: 14px 18px 14px 24px;
  border-radius: 99px;
  color: white;
  background: var(--forest);
  font-size: 14px;
  font-weight: 800;
  text-decoration: none;
  transition: transform 180ms ease, box-shadow 180ms ease;
}

.primary-cta span {
  display: grid;
  width: 28px;
  height: 28px;
  place-items: center;
  border-radius: 50%;
  color: var(--forest);
  background: white;
}

.primary-cta:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 26px rgba(23, 63, 53, 0.18);
}

.hero-demo {
  position: relative;
  overflow: hidden;
  padding: clamp(32px, 5vw, 64px);
  border: 1px solid rgba(24, 32, 30, 0.1);
  border-radius: var(--radius-lg);
  background: var(--white);
  box-shadow: var(--shadow);
}

.hero-demo::before {
  position: absolute;
  top: -85px;
  right: -75px;
  width: 220px;
  height: 220px;
  border: 52px solid var(--about-soft);
  border-radius: 50%;
  content: "";
}

.demo-label {
  position: relative;
  margin-bottom: 42px;
  color: #777e7a;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.16em;
}

.sentence-stem {
  position: relative;
  margin: 0 0 12px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(28px, 3.6vw, 48px);
  font-weight: 700;
  letter-spacing: -0.035em;
  line-height: 1.15;
}

.syntax-block {
  position: relative;
  display: grid;
  min-width: 0;
  padding: 22px 22px 22px 26px;
  border: 2px solid;
  border-left-width: 6px;
  border-radius: 5px 16px 16px 5px;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 14px;
  align-items: start;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(19px, 2.3vw, 30px);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.35;
}

.syntax-with {
  border-color: var(--with);
  background: var(--with-soft);
}

.syntax-about {
  margin-top: 15px;
  border-color: var(--about);
  background: var(--about-soft);
  font-size: 0.82em;
}

.syntax-tag {
  display: inline-flex;
  min-height: 28px;
  align-items: center;
  padding: 2px 9px;
  border-radius: 6px;
  color: white;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.5em;
  font-weight: 800;
  letter-spacing: 0;
  line-height: 1;
}

.syntax-with > .syntax-tag {
  background: var(--with);
}

.syntax-about > .syntax-tag {
  background: var(--about);
}

.syntax-content {
  min-width: 0;
  overflow-wrap: anywhere;
}

.demo-note {
  margin: 22px 0 0;
  color: #656d69;
  font-size: 13px;
  font-weight: 700;
}

.demo-note span {
  margin-right: 7px;
  color: var(--with);
}

.section {
  display: grid;
  max-width: 1100px;
  margin: 0 auto;
  padding: 130px 5vw;
  grid-template-columns: minmax(280px, 0.82fr) minmax(0, 1.18fr);
  gap: clamp(60px, 9vw, 120px);
}

.section-heading h2,
.closing-section h2 {
  font-size: clamp(34px, 4.4vw, 58px);
}

.problem-content {
  display: grid;
  gap: 45px;
}

.translation-list {
  display: grid;
  gap: 8px;
  padding: 30px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.45);
}

.translation-list p {
  display: grid;
  margin: 0;
  grid-template-columns: 90px 22px 1fr;
  font-size: 18px;
}

.translation-list code {
  border: 0;
  background: none;
  font-size: 1em;
  font-weight: 800;
}

.translation-list s {
  color: #777d7a;
  text-decoration-color: var(--with);
  text-decoration-thickness: 2px;
}

.prose {
  color: #4c5551;
  font-size: 15px;
}

.prose p:first-child {
  margin-top: 0;
}

.example-chips {
  display: flex;
  margin: 24px 0;
  padding: 0;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
}

.example-chips li {
  padding: 5px 12px;
  border: 1px solid var(--line);
  border-radius: 99px;
  background: var(--white);
  font-family: Georgia, serif;
  font-size: 13px;
}

.key-message {
  margin-top: 32px;
  padding-left: 20px;
  border-left: 4px solid var(--with);
  color: var(--ink);
  font-size: 17px;
}

.builder-section,
.practice-section {
  padding: 130px max(5vw, calc((100vw - 1040px) / 2));
  color: white;
  background: var(--forest);
}

.light-heading {
  max-width: 760px;
}

.light-heading .section-number {
  color: #9fbcb4;
}

.light-heading h2 {
  color: white;
}

.light-heading > p:last-child {
  color: #c0d0cb;
  font-size: 14px;
}

.builder {
  margin-top: 55px;
}

.step-controls {
  display: grid;
  margin-bottom: 18px;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}

.step-button {
  display: flex;
  min-height: 52px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 1px solid rgba(255, 255, 255, 0.17);
  border-radius: 12px;
  color: #b7c9c4;
  background: transparent;
  cursor: pointer;
  font-size: 12px;
  font-weight: 800;
}

.step-button span {
  display: grid;
  width: 22px;
  height: 22px;
  place-items: center;
  border: 1px solid currentColor;
  border-radius: 50%;
  font-family: ui-monospace, monospace;
  font-size: 10px;
}

.step-button:hover,
.step-button:focus-visible {
  border-color: #fff;
  color: white;
}

.step-button.is-active {
  border-color: white;
  color: var(--forest);
  background: white;
}

.builder-stage {
  min-height: 540px;
  padding: clamp(26px, 5vw, 58px);
  border-radius: var(--radius-lg);
  color: var(--ink);
  background: var(--white);
  box-shadow: 0 30px 80px rgba(4, 20, 16, 0.26);
}

.builder-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: #6e7773;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.12em;
}

.growth-meter {
  overflow: hidden;
  width: min(220px, 45%);
  height: 4px;
  border-radius: 99px;
  background: #e3e2dc;
}

.growth-meter i {
  display: block;
  width: 25%;
  height: 100%;
  border-radius: inherit;
  background: var(--with);
  transition: width 300ms ease;
}

.builder-sentence {
  display: flex;
  min-height: 245px;
  padding: 52px 0 36px;
  flex-direction: column;
  justify-content: center;
}

.builder-sentence.is-changing {
  animation: sentence-in 280ms ease both;
}

@keyframes sentence-in {
  from { opacity: 0; transform: translateY(9px); }
  to { opacity: 1; transform: translateY(0); }
}

.builder-sentence .sentence-stem {
  font-size: clamp(29px, 4vw, 52px);
}

.builder-sentence .syntax-block {
  font-size: clamp(20px, 3vw, 38px);
}

.builder-explanation {
  display: grid;
  padding: 20px 0;
  border-top: 1px solid #deddd7;
  grid-template-columns: 46px minmax(0, 1fr);
  gap: 16px;
  align-items: start;
}

.builder-explanation p {
  margin: 0;
  color: #4f5753;
  font-size: 14px;
}

.explanation-mark {
  display: grid;
  width: 36px;
  height: 36px;
  place-items: center;
  border-radius: 50%;
  color: white;
  background: var(--with);
  font-family: ui-monospace, monospace;
  font-size: 10px;
  font-weight: 800;
}

.builder-actions {
  display: flex;
  margin-top: 25px;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.text-button,
.next-button {
  border: 0;
  cursor: pointer;
  font-weight: 800;
}

.text-button {
  padding: 10px 0;
  color: #69716d;
  background: transparent;
  font-size: 12px;
}

.text-button:disabled {
  cursor: default;
  opacity: 0.28;
}

.next-button {
  min-height: 48px;
  padding: 10px 18px;
  border-radius: 99px;
  color: white;
  background: var(--forest);
  font-size: 12px;
}

.next-button:disabled {
  cursor: default;
  opacity: 0.45;
}

.builder-insight {
  display: flex;
  max-width: 760px;
  margin: 42px auto 0;
  align-items: center;
  gap: 18px;
  justify-content: center;
  text-align: center;
}

.builder-insight p {
  margin: 0;
  color: #d8e3df;
  font-family: "Yu Mincho", "Hiragino Mincho ProN", Georgia, serif;
  font-size: clamp(19px, 2.4vw, 28px);
  line-height: 1.55;
}

.insight-icon {
  display: grid;
  width: 40px;
  height: 40px;
  flex: 0 0 auto;
  place-items: center;
  border: 1px solid #e1c353;
  border-radius: 50%;
  color: #e1c353;
  font-family: Georgia, serif;
  font-weight: 800;
}

.noscript-steps {
  margin-top: 20px;
  color: white;
}

.state-card {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--white);
}

.state-visual {
  padding: 38px;
  background: #edece7;
}

.compact-block {
  font-size: clamp(23px, 3vw, 36px);
}

.compact-block .syntax-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 15px;
}

.state-pill {
  padding: 3px 13px;
  border-radius: 99px;
  color: white;
  background: var(--forest);
  font-family: ui-monospace, monospace;
  font-size: 0.54em;
}

.state-equation {
  display: flex;
  margin-top: 20px;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
  color: #5c6561;
  font-size: 12px;
}

.state-equation i {
  color: #979d9a;
  font-style: normal;
}

.state-equation strong {
  color: var(--with);
}

.state-card .prose {
  padding: 34px 38px;
}

.relations-section {
  padding: 130px max(5vw, calc((100vw - 1040px) / 2));
}

.centered-heading {
  max-width: 700px;
  margin: 0 auto 65px;
  text-align: center;
}

.centered-heading > p:last-child {
  color: var(--muted);
  font-size: 14px;
}

.relation-card {
  display: grid;
  overflow: hidden;
  min-height: 380px;
  margin-top: 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--white);
  grid-template-columns: 0.75fr 1.25fr;
  grid-template-rows: auto 1fr;
}

.relation-card header {
  display: flex;
  padding: 30px 36px;
  border-bottom: 1px solid var(--line);
  grid-column: 1 / -1;
  align-items: center;
  justify-content: space-between;
}

.relation-card header > div {
  display: flex;
  align-items: center;
  gap: 18px;
}

.relation-card h3 {
  margin: 0;
  font-family: Georgia, serif;
  font-size: clamp(34px, 4vw, 52px);
  line-height: 1;
}

.relation-card header p {
  margin: 0;
  font-size: 13px;
  font-weight: 800;
}

.relation-index {
  color: #8d9591;
  font-family: ui-monospace, monospace;
  font-size: 11px;
}

.relation-diagram {
  position: relative;
  display: flex;
  min-height: 280px;
  align-items: center;
  justify-content: center;
}

.relation-with .relation-diagram { background: var(--with-soft); }
.relation-about .relation-diagram { background: var(--about-soft); }
.relation-from .relation-diagram { background: var(--from-soft); }

.with-diagram {
  gap: 0;
}

.diagram-node,
.source-node,
.result-node {
  display: grid;
  width: 88px;
  height: 88px;
  place-items: center;
  border: 2px solid currentColor;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.75);
  font-family: Georgia, serif;
  font-size: 23px;
  font-weight: 700;
  text-align: center;
}

.with-diagram .diagram-node { color: var(--with); }

.diagram-line {
  position: relative;
  width: 100px;
  color: var(--with);
  font-family: ui-monospace, monospace;
  font-size: 9px;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-align: center;
}

.diagram-line::before {
  position: absolute;
  z-index: 0;
  top: 50%;
  right: 0;
  left: 0;
  height: 2px;
  background: currentColor;
  content: "";
}

.diagram-line { z-index: 1; }
.diagram-line::after {
  position: absolute;
  z-index: -1;
  inset: -5px 25px;
  background: var(--with-soft);
  content: "";
}

.about-diagram::before,
.about-diagram::after {
  position: absolute;
  width: 160px;
  height: 160px;
  border: 1px dashed var(--about);
  border-radius: 50%;
  content: "";
}

.about-diagram::after {
  width: 215px;
  height: 215px;
  opacity: 0.45;
}

.about-diagram .diagram-node {
  z-index: 1;
  color: var(--about);
  font-size: 18px;
}

.orbit-label {
  position: absolute;
  z-index: 2;
  padding: 3px 8px;
  border-radius: 99px;
  color: white;
  background: var(--about);
  font-family: ui-monospace, monospace;
  font-size: 9px;
  font-weight: 800;
}

.orbit-one { top: 33px; left: 25%; }
.orbit-two { right: 17%; bottom: 45px; }

.from-diagram {
  gap: 0;
}

.source-node,
.result-node {
  width: 92px;
  height: 92px;
  border-radius: 18px;
  color: var(--from);
  font-size: 14px;
  line-height: 1.3;
}

.arrow-track {
  position: relative;
  width: 90px;
  height: 2px;
  background: var(--from);
}

.arrow-track::after {
  position: absolute;
  top: -4px;
  right: -1px;
  width: 8px;
  height: 8px;
  transform: rotate(45deg);
  border-top: 2px solid var(--from);
  border-right: 2px solid var(--from);
  content: "";
}

.arrow-track small {
  position: absolute;
  top: -24px;
  left: 50%;
  transform: translateX(-50%);
  color: var(--from);
  font-family: ui-monospace, monospace;
  font-size: 8px;
  font-weight: 800;
}

.relation-examples {
  display: grid;
  padding: 22px 38px;
  align-content: center;
}

.relation-examples > div {
  padding: 15px 0;
  border-bottom: 1px solid #e3e0d8;
}

.relation-examples > div:last-child {
  border-bottom: 0;
}

.relation-examples p {
  margin: 0;
  font-family: Georgia, serif;
  font-size: clamp(16px, 1.8vw, 20px);
  line-height: 1.45;
}

.relation-examples span {
  display: block;
  margin-top: 4px;
  color: #69716e;
  font-size: 11px;
  line-height: 1.5;
}

.relation-with b { color: var(--with); }
.relation-about b { color: var(--about); }
.relation-from b { color: var(--from); }

.practice-section {
  background: #1e2926;
}

.practice-list {
  display: grid;
  margin-top: 55px;
  border-top: 1px solid rgba(255, 255, 255, 0.22);
}

.practice-card {
  border-bottom: 1px solid rgba(255, 255, 255, 0.22);
}

.practice-card summary {
  display: grid;
  min-height: 96px;
  padding: 22px 4px;
  align-items: center;
  grid-template-columns: 64px minmax(0, 1fr) auto;
  gap: 16px;
  cursor: pointer;
  list-style: none;
}

.practice-card summary::-webkit-details-marker { display: none; }

.practice-card summary > span:nth-child(2) {
  font-family: "Yu Mincho", "Hiragino Mincho ProN", Georgia, serif;
  font-size: clamp(17px, 2.2vw, 23px);
  font-weight: 600;
  line-height: 1.5;
}

.question-number {
  color: #9cb7af;
  font-family: ui-monospace, monospace;
  font-size: 11px;
  font-weight: 800;
}

.practice-card summary small {
  color: #a8b8b3;
  font-size: 10px;
  font-weight: 800;
}

.practice-card[open] summary small {
  color: white;
  font-size: 0;
}

.practice-card[open] summary small::after {
  font-size: 10px;
  content: "問題を閉じる −";
}

.answer {
  margin: 0 0 24px 64px;
  padding: 24px 28px;
  border-radius: 16px;
  color: var(--ink);
  background: var(--white);
}

.answer > span {
  color: var(--with);
  font-family: ui-monospace, monospace;
  font-size: 9px;
  font-weight: 800;
  letter-spacing: 0.12em;
}

.answer p {
  margin: 5px 0 0;
  font-family: Georgia, serif;
  font-size: clamp(18px, 2.4vw, 26px);
  line-height: 1.5;
}

.answer b { color: var(--with); }

.next-section {
  align-items: start;
}

.preposition-grid {
  display: grid;
  border-top: 1px solid var(--line);
  grid-template-columns: repeat(2, 1fr);
}

.preposition-grid > div {
  display: flex;
  min-height: 110px;
  align-items: center;
  gap: 18px;
  padding: 18px 22px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.preposition-grid > div:nth-child(even) { border-right: 0; }

.preposition-grid b {
  color: var(--forest);
  font-family: Georgia, serif;
  font-size: 31px;
}

.preposition-grid span {
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}

.closing-section {
  padding: 130px max(5vw, calc((100vw - 900px) / 2));
  text-align: center;
  background: #e8dfcf;
}

.closing-steps {
  display: grid;
  max-width: 630px;
  margin: 55px auto 42px;
  gap: 9px;
  text-align: left;
}

.closing-steps p {
  display: grid;
  margin: 0;
  padding: 18px 22px;
  border: 1px solid rgba(24, 32, 30, 0.16);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.38);
  grid-template-columns: 38px 1fr;
  align-items: center;
  font-size: 14px;
}

.closing-steps span {
  font-family: Georgia, serif;
  font-size: 18px;
  font-weight: 700;
}

.closing-copy {
  margin: 0 auto 34px;
  line-height: 2;
}

.dark-cta {
  color: var(--ink);
  background: white;
}

.dark-cta span {
  color: white;
  background: var(--ink);
}

.grammar-note {
  display: grid;
  max-width: 900px;
  margin: 0 auto;
  padding: 58px 5vw;
  grid-template-columns: 180px 1fr;
  gap: 34px;
}

.grammar-note h2 {
  margin: 0;
  font-size: 13px;
}

.grammar-note p {
  margin: 0;
  color: var(--muted);
  font-size: 12px;
}

.site-footer {
  display: flex;
  min-height: 120px;
  align-items: center;
  justify-content: space-between;
  padding: 30px 5vw;
  border-top: 1px solid var(--line);
}

.site-footer p {
  color: var(--muted);
  font-size: 11px;
}

button:focus-visible,
a:focus-visible,
summary:focus-visible {
  outline: 3px solid #e1c353;
  outline-offset: 4px;
}

.story-teaser {
  display: grid;
  gap: 24px;
}

.story-teaser::before {
  border-color: #ffe7e0;
}

.teaser-screen {
  position: relative;
  z-index: 1;
  display: grid;
  padding: 18px;
  border: 1px solid #dedbd3;
  border-radius: 18px;
  background: #f5f3ee;
  gap: 12px;
}

.screen-top {
  display: grid;
  margin-bottom: 4px;
  grid-template-columns: 24px 1fr auto;
  align-items: center;
  color: #6a716e;
  font-family: ui-monospace, monospace;
  font-size: 11px;
}

.screen-top > span {
  width: 17px;
  height: 12px;
  border-radius: 4px;
  background: var(--with);
}

.screen-top i {
  color: #a2a6a3;
  font-style: normal;
  letter-spacing: 2px;
}

.video-row {
  display: grid;
  padding: 10px;
  border-radius: 11px;
  background: white;
  grid-template-columns: 74px 1fr;
  gap: 13px;
}

.play-mark {
  display: grid;
  min-height: 47px;
  place-items: center;
  border-radius: 7px;
  color: white;
  background: #29322f;
  font-size: 10px;
}

.video-row > div {
  display: grid;
  align-content: center;
  gap: 8px;
}

.video-row i {
  display: block;
  width: 90%;
  height: 6px;
  border-radius: 99px;
  background: #d9d8d3;
}

.video-row i:last-child {
  width: 58%;
}

.teaser-dialogue {
  position: relative;
  z-index: 2;
  display: grid;
  gap: 10px;
}

.teaser-dialogue p {
  margin: 0;
  padding: 14px 17px;
  border-radius: 15px;
  font-size: 13px;
  font-weight: 700;
  line-height: 1.65;
}

.teaser-dialogue p span {
  display: block;
  margin-bottom: 2px;
  font-family: ui-monospace, monospace;
  font-size: 8px;
  letter-spacing: 0.12em;
}

.mom-line {
  margin-right: 28px !important;
  background: var(--with-soft);
}

.mom-line span { color: var(--with); }

.my-line {
  margin-left: 54px !important;
  background: #e9efec;
}

.my-line span { color: var(--forest); }

.story-section {
  padding: 130px max(5vw, calc((100vw - 1040px) / 2));
  background: #ece4d7;
}

.story-heading {
  display: grid;
  max-width: 900px;
  margin-bottom: 62px;
  grid-template-columns: minmax(0, 1fr) minmax(250px, 0.55fr);
  column-gap: 70px;
  align-items: end;
}

.story-heading .section-number {
  grid-column: 1 / -1;
}

.story-heading > p:last-child {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 14px;
}

.story-timeline {
  margin: 0;
  padding: 0;
  border-top: 1px solid rgba(24, 32, 30, 0.2);
  list-style: none;
}

.story-event {
  display: grid;
  min-height: 185px;
  padding: 32px 0;
  border-bottom: 1px solid rgba(24, 32, 30, 0.2);
  grid-template-columns: 160px minmax(0, 1fr);
  gap: 30px;
  align-items: start;
}

.story-time {
  display: flex;
  align-items: center;
  gap: 14px;
}

.story-time span {
  display: grid;
  width: 48px;
  height: 48px;
  place-items: center;
  border-radius: 50%;
  color: white;
  background: var(--forest);
  font-family: Georgia, serif;
  font-size: 17px;
}

.story-time small {
  color: #66706c;
  font-size: 11px;
  font-weight: 800;
}

.story-copy {
  display: grid;
  max-width: 760px;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 0.75fr);
  column-gap: 40px;
}

.story-copy h3 {
  margin: 0 0 8px;
  font-family: "Yu Mincho", "Hiragino Mincho ProN", Georgia, serif;
  font-size: clamp(21px, 2.7vw, 30px);
  line-height: 1.5;
}

.story-copy > p:not(.story-english) {
  margin: 0;
  color: #5a625f;
  font-size: 13px;
  grid-column: 1;
}

.story-english,
.story-copy blockquote {
  margin: 0;
  padding: 16px 18px;
  border-left: 4px solid var(--with);
  color: var(--ink);
  background: rgba(255, 255, 255, 0.55);
  font-family: Georgia, serif;
  font-size: clamp(16px, 1.8vw, 20px);
  font-style: normal;
  line-height: 1.5;
  grid-column: 2;
  grid-row: 1 / span 2;
}

.story-english b { color: var(--from); }

.ingredient-board {
  display: grid;
  margin-top: 70px;
  padding: clamp(28px, 5vw, 52px);
  border-radius: var(--radius-lg);
  color: white;
  background: var(--forest);
  grid-template-columns: minmax(230px, 0.8fr) minmax(0, 1.2fr);
  gap: 45px 70px;
  box-shadow: 0 25px 65px rgba(23, 63, 53, 0.18);
}

.ingredient-intro .section-number { color: #9fbcb4; }

.ingredient-intro h3 {
  margin: 0 0 20px;
  font-family: "Yu Mincho", "Hiragino Mincho ProN", Georgia, serif;
  font-size: clamp(27px, 3.5vw, 43px);
  line-height: 1.35;
}

.ingredient-intro > p:last-child {
  margin: 0;
  color: #bfd0ca;
  font-size: 12px;
}

.ingredient-list {
  display: grid;
  margin: 0;
  padding: 0;
  gap: 8px;
  list-style: none;
}

.ingredient-list li {
  display: grid;
  min-height: 68px;
  padding: 13px 17px;
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.07);
  grid-template-columns: 120px minmax(0, 1fr);
  align-items: center;
}

.ingredient-list span {
  color: #abc0ba;
  font-size: 10px;
  font-weight: 800;
}

.ingredient-list b {
  overflow-wrap: anywhere;
  font-family: Georgia, serif;
  font-size: clamp(16px, 2vw, 21px);
}

.ingredient-cta {
  display: flex;
  min-height: 54px;
  padding: 12px 20px;
  border-radius: 99px;
  color: var(--ink);
  background: white;
  grid-column: 1 / -1;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  font-weight: 800;
  text-decoration: none;
}

.ingredient-cta span {
  display: grid;
  width: 28px;
  height: 28px;
  place-items: center;
  border-radius: 50%;
  color: white;
  background: var(--with);
}

.builder-context {
  display: flex;
  margin-top: 42px;
  padding: 16px 18px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 14px;
  align-items: center;
  flex-wrap: wrap;
  gap: 9px;
}

.builder-context > span {
  margin-right: 8px;
  color: #a7bdb6;
  font-size: 9px;
  font-weight: 800;
}

.builder-context p {
  margin: 0;
  padding: 5px 9px;
  border-radius: 6px;
  color: var(--ink);
  background: white;
  font-family: Georgia, serif;
  font-size: 12px;
  font-weight: 700;
}

.builder-context i {
  color: #78948b;
  font-style: normal;
  font-size: 11px;
}


/* Story handoff */
.lesson-context-gate {
  display: grid;
  padding: 82px max(5vw, calc((100vw - 1120px) / 2));
  border-bottom: 1px solid var(--line);
  background: #ebe5d9;
  grid-template-columns: 1.1fr .9fr;
  gap: 70px;
  align-items: center;
}

.lesson-context-gate h2 {
  margin: 0;
  font-family: "Yu Mincho", "Hiragino Mincho ProN", Georgia, serif;
  font-size: clamp(31px, 4vw, 49px);
  line-height: 1.4;
}

.lesson-context-gate > div > p:last-child {
  max-width: 620px;
  margin: 24px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.lesson-context-gate > a {
  display: grid;
  min-height: 150px;
  padding: 26px;
  align-items: center;
  color: white;
  background: var(--forest);
  grid-template-columns: 1fr 38px;
  gap: 10px;
  text-decoration: none;
}

.lesson-context-gate > a span {
  grid-column: 1 / -1;
  color: #c8dbd4;
  font-family: ui-monospace, monospace;
  font-size: 9px;
  font-weight: 900;
  letter-spacing: .13em;
}

.lesson-context-gate > a b {
  font-family: "Yu Mincho", Georgia, serif;
  font-size: clamp(18px, 2vw, 24px);
}

.lesson-context-gate > a i {
  display: grid;
  width: 36px;
  height: 36px;
  place-items: center;
  color: var(--forest);
  background: white;
  font-style: normal;
}

/* Expanded lesson content */
.lesson-map {
  padding: 80px max(5vw, calc((100vw - 1120px) / 2));
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--white);
}

.lesson-map-grid { display: grid; grid-template-columns: minmax(240px, 0.7fr) minmax(0, 1.3fr); gap: clamp(42px, 7vw, 96px); align-items: start; }
.lesson-map-intro h2 { margin: 0; font-family: "Yu Mincho", "Hiragino Mincho ProN", Georgia, serif; font-size: clamp(32px, 4vw, 50px); font-weight: 600; letter-spacing: -0.045em; line-height: 1.3; }
.lesson-goals { display: grid; margin: 0; padding: 0; list-style: none; }
.lesson-goals li { display: grid; padding: 20px 0; border-bottom: 1px solid var(--line); grid-template-columns: 46px 1fr; gap: 18px; align-items: start; }
.lesson-goals li:first-child { border-top: 1px solid var(--line); }
.lesson-goals span { color: var(--with); font-family: Georgia, serif; font-size: 17px; font-weight: 700; }
.lesson-goals p { margin: 0; font-size: 15px; font-weight: 700; line-height: 1.8; }
.important-note { display: grid; margin-top: 48px; padding: 25px 28px; border: 1px solid rgba(23, 63, 53, 0.18); border-left: 5px solid var(--forest); border-radius: 0 16px 16px 0; background: #eef4f0; grid-template-columns: 110px 1fr; gap: 26px; align-items: start; }
.important-note p { margin: 0; font-size: 14px; }
.note-label { padding-top: 2px; color: var(--forest); font-family: ui-monospace, monospace; font-size: 10px; font-weight: 900; letter-spacing: 0.13em; }

.builder-translation { display: grid; max-width: 960px; margin: 22px auto 0; padding: 20px 24px; border: 1px solid rgba(255, 255, 255, 0.16); border-radius: 14px; grid-template-columns: 100px 1fr; gap: 20px; color: white; background: rgba(255, 255, 255, 0.06); }
.builder-translation span { color: #9eb6ae; font-family: ui-monospace, monospace; font-size: 9px; font-weight: 900; letter-spacing: 0.14em; }
.builder-translation p { margin: 0; font-size: 13px; }
.state-visual-label { margin: 0 0 10px; color: var(--muted); font-size: 10px; font-weight: 900; letter-spacing: 0.1em; }
.state-visual-label.second-label { margin-top: 28px; }
.state-example-block .syntax-content { display: flex; align-items: center; gap: 8px; }
.state-example-block .syntax-content span { color: var(--with); }

.relation-by .relation-diagram { background: var(--by-soft); }
.relation-on .relation-diagram { background: var(--on-soft); }
.relation-by b { color: var(--by); }
.relation-on b { color: var(--on); }
.method-diagram { display: flex; align-items: center; justify-content: center; gap: clamp(10px, 2vw, 26px); }
.method-node, .method-goal, .status-person { display: grid; min-width: 88px; min-height: 88px; place-items: center; border: 2px solid var(--by); border-radius: 18px; color: var(--by); background: white; font-family: ui-monospace, monospace; font-size: 11px; font-weight: 900; letter-spacing: 0.08em; }
.method-goal { border-color: var(--forest); color: white; background: var(--forest); }
.method-arrow { color: var(--by); font-family: ui-monospace, monospace; font-size: 10px; font-weight: 900; letter-spacing: 0.12em; }
.method-arrow i { margin-left: 4px; font-style: normal; }
.status-diagram { display: flex; align-items: center; justify-content: center; }
.status-person { z-index: 2; border-color: var(--on); color: var(--on); }
.status-field { display: grid; width: 150px; min-height: 150px; margin-left: -22px; padding-left: 24px; place-items: center; border: 2px dashed rgba(184, 125, 24, 0.6); border-radius: 50%; color: var(--on); font-family: ui-monospace, monospace; font-size: 10px; font-weight: 900; letter-spacing: 0.1em; text-align: center; }
.status-field b { color: var(--ink); font-size: 12px; }
.relation-tip { display: grid; max-width: 900px; margin: -18px auto 56px; padding: 22px 26px; border: 1px solid rgba(43, 139, 104, 0.25); border-left: 5px solid var(--by); border-radius: 0 14px 14px 0; background: var(--by-soft); grid-template-columns: 120px 1fr; gap: 24px; }
.relation-tip > span { color: var(--by); font-family: ui-monospace, monospace; font-size: 10px; font-weight: 900; letter-spacing: 0.12em; }
.relation-tip p { margin: 0; font-size: 13px; }
.relation-tip b { color: var(--by); }
.from-tip { border-color: rgba(108, 88, 164, 0.25); border-left-color: var(--from); background: var(--from-soft); }
.from-tip > span, .from-tip b { color: var(--from); }

.comparison-section { padding: 120px max(5vw, calc((100vw - 1120px) / 2)); border-top: 1px solid var(--line); background: var(--white); }
.comparison-heading { display: grid; max-width: 880px; margin-bottom: 55px; grid-template-columns: 1fr 1fr; gap: 20px 60px; align-items: end; }
.comparison-heading .section-number { grid-column: 1 / -1; }
.comparison-heading p:last-child { margin: 0; color: var(--muted); font-size: 14px; }
.relation-table { overflow: hidden; border: 1px solid var(--line); border-radius: 18px; }
.relation-table-row { display: grid; min-height: 78px; padding: 18px 22px; border-bottom: 1px solid var(--line); grid-template-columns: 1.2fr 0.8fr 1.4fr; gap: 26px; align-items: center; }
.relation-table-row:last-child { border-bottom: 0; }
.relation-table-row:nth-child(even) { background: var(--paper); }
.relation-table-row code { width: fit-content; border: 0; background: transparent; font-size: 13px; font-weight: 800; }
.relation-table-row b { color: var(--forest); font-size: 13px; }
.relation-table-row > span { color: var(--muted); font-size: 12px; }
.relation-table-row.table-head { min-height: 48px; padding-top: 12px; padding-bottom: 12px; color: white; background: var(--forest); }
.table-head span { color: #d8e3df; font-family: ui-monospace, monospace; font-size: 9px; font-weight: 900; letter-spacing: 0.12em; }
.choice-workflow { display: grid; margin-top: 70px; padding: 45px; border-radius: 24px; background: var(--paper); grid-template-columns: 0.7fr 1.3fr; gap: 55px; }
.choice-intro h3 { margin: 0; font-family: "Yu Mincho", "Hiragino Mincho ProN", Georgia, serif; font-size: clamp(28px, 3vw, 40px); line-height: 1.35; }
.choice-workflow ol { display: grid; margin: 0; padding: 0; list-style: none; gap: 10px; }
.choice-workflow li { display: grid; padding: 14px 0; border-bottom: 1px solid var(--line); grid-template-columns: 42px 1fr; gap: 12px; }
.choice-workflow li:last-child { border-bottom: 0; }
.choice-workflow li > span { color: var(--with); font-family: Georgia, serif; font-size: 18px; font-weight: 700; }
.choice-workflow li p { margin: 0; font-size: 13px; }
.choice-examples { display: grid; margin-top: 18px; grid-template-columns: 1fr 1fr; gap: 18px; }
.choice-examples article { padding: 28px; border: 1px solid var(--line); border-radius: 18px; }
.choice-examples article > span { color: var(--with); font-family: ui-monospace, monospace; font-size: 9px; font-weight: 900; letter-spacing: 0.13em; }
.choice-examples p { margin: 8px 0 4px; color: var(--muted); font-size: 12px; }
.choice-examples h3 { margin: 0; font-family: Georgia, serif; font-size: 20px; line-height: 1.6; }
.choice-examples b { color: var(--with); }

.expanded-practice { max-width: 1020px; margin-right: auto; margin-left: auto; }
.question-body { padding: 8px 64px 30px; color: #dce6e2; }
.question-body > ol { display: grid; margin: 0; padding-left: 28px; gap: 13px; }
.question-body li { padding-left: 8px; font-size: 14px; }
.answer-reveal { margin-top: 26px; border: 1px solid rgba(255, 255, 255, 0.2); border-radius: 14px; background: rgba(255, 255, 255, 0.05); }
.practice-card .answer-reveal > summary { display: flex; min-height: auto; padding: 14px 18px; cursor: pointer; color: white; background: transparent; font-size: 12px; font-weight: 800; }
.practice-card .answer-reveal[open] > summary { border-bottom: 1px solid rgba(255, 255, 255, 0.14); }
.answer-reveal > div { padding: 18px 24px; color: var(--ink); background: var(--white); border-radius: 0 0 13px 13px; }
.answer-reveal ol { display: grid; margin: 0; padding-left: 22px; gap: 8px; }
.answer-reveal b { color: var(--with); }
.answer-sentences { font-family: Georgia, serif; font-size: 16px; }

.learning-path { display: grid; margin: 0; padding: 0; border-top: 1px solid var(--line); list-style: none; }
.learning-path li { display: grid; min-height: 82px; padding: 16px 20px; border-bottom: 1px solid var(--line); grid-template-columns: 42px 1fr auto; gap: 18px; align-items: center; }
.learning-path li > span { color: var(--muted); font-family: Georgia, serif; font-size: 16px; }
.learning-path b { color: var(--forest); font-family: Georgia, serif; font-size: 22px; }
.learning-path small { color: var(--muted); font-size: 10px; font-weight: 800; }
.learning-path .is-current { background: var(--with-soft); }
.learning-path .is-current > span, .learning-path .is-current b { color: var(--with); }
.summary-list { display: grid; max-width: 760px; margin: 55px auto 40px; padding: 0; list-style: none; gap: 8px; text-align: left; }
.summary-list li { display: grid; padding: 18px 22px; border: 1px solid rgba(24, 32, 30, 0.16); border-radius: 12px; background: rgba(255, 255, 255, 0.42); grid-template-columns: 42px 1fr; align-items: start; }
.summary-list span { font-family: Georgia, serif; font-size: 17px; font-weight: 700; }
.summary-list p { margin: 0; font-size: 13px; }
.summary-list code { background: rgba(255, 255, 255, 0.7); }
.closing-quote { max-width: 760px; margin: 0 auto 36px; padding: 28px; border: 0; color: var(--forest); font-family: "Yu Mincho", "Hiragino Mincho ProN", Georgia, serif; font-size: clamp(20px, 2.7vw, 30px); font-weight: 700; line-height: 1.65; }
.closing-quote span { display: block; margin-bottom: 10px; color: var(--with); font-family: ui-monospace, monospace; font-size: 9px; font-weight: 900; letter-spacing: 0.16em; }

@media (max-width: 820px) {
  .lesson-map, .comparison-section { padding: 80px 20px; }
  .lesson-context-gate { padding: 70px 20px; grid-template-columns: 1fr; gap: 30px; }
  .lesson-map-grid, .comparison-heading, .choice-workflow { grid-template-columns: 1fr; }
  .lesson-map-grid { gap: 34px; }
  .important-note { grid-template-columns: 1fr; gap: 10px; }
  .builder-translation { grid-template-columns: 1fr; gap: 8px; }
  .relation-tip { margin-top: -8px; grid-template-columns: 1fr; gap: 8px; }
  .comparison-heading { gap: 22px; margin-bottom: 40px; }
  .comparison-heading .section-number { grid-column: 1; }
  .relation-table { border: 0; border-radius: 0; }
  .relation-table-row { margin-bottom: 12px; padding: 20px; border: 1px solid var(--line); border-radius: 14px; grid-template-columns: 1fr; gap: 8px; }
  .relation-table-row:last-child { border-bottom: 1px solid var(--line); }
  .relation-table-row.table-head { display: none; }
  .choice-workflow { padding: 28px 22px; gap: 24px; }
  .choice-examples { grid-template-columns: 1fr; }
  .question-body { padding: 8px 20px 24px; }
  .answer-reveal > div { padding: 18px; }
  .learning-path li { grid-template-columns: 36px 1fr; }
  .learning-path small { grid-column: 2; }
  .summary-list { margin-top: 40px; }
  .summary-list li { grid-template-columns: 34px 1fr; padding: 16px; }

  .story-section { padding: 90px 20px; }

  .story-heading {
    margin-bottom: 42px;
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .story-heading .section-number { grid-column: 1; }

  .story-event {
    min-height: auto;
    padding: 28px 0;
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .story-copy {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .story-copy > p:not(.story-english) { grid-column: 1; }

  .story-english,
  .story-copy blockquote {
    grid-column: 1;
    grid-row: auto;
  }

  .ingredient-board {
    margin-top: 48px;
    padding: 28px 20px;
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .ingredient-cta { grid-column: 1; }

  .builder-context { margin-top: 30px; }

  .site-header { padding: 0 20px; }
  .section-nav { display: none; }

  .hero {
    min-height: auto;
    padding: 74px 20px 88px;
    grid-template-columns: 1fr;
    gap: 60px;
  }



  .hero-demo {
    padding: 30px 22px;
    border-radius: 22px;
  }

  .syntax-block {
    padding: 16px 14px;
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .syntax-tag { width: fit-content; }

  .section {
    padding: 90px 20px;
    grid-template-columns: 1fr;
    gap: 42px;
  }

  .builder-section,
  .relations-section,
  .practice-section,
  .closing-section {
    padding: 90px 20px;
  }

  .step-controls {
    overflow-x: auto;
    padding-bottom: 4px;
    grid-template-columns: repeat(4, minmax(105px, 1fr));
  }

  .builder-stage {
    min-height: 510px;
    padding: 26px 20px;
    border-radius: 20px;
  }

  .builder-sentence { min-height: 270px; }

  .builder-actions { align-items: stretch; }
  .text-button, .next-button { flex: 1; }

  .builder-insight {
    align-items: flex-start;
    text-align: left;
  }

  .state-visual,
  .state-card .prose { padding: 25px 20px; }

  .relation-card {
    grid-template-columns: 1fr;
  }

  .relation-card header {
    padding: 24px 22px;
  }

  .relation-card header p {
    max-width: 130px;
    line-height: 1.5;
    text-align: right;
  }

  .relation-diagram { min-height: 230px; }
  .relation-examples { padding: 18px 22px; }

  .practice-card summary {
    min-height: 100px;
    grid-template-columns: 42px minmax(0, 1fr);
  }

  .practice-card summary small {
    padding-left: 42px;
    grid-column: 1 / -1;
  }

  .answer {
    margin-left: 0;
    padding: 20px;
  }

  .grammar-note {
    padding: 50px 20px;
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .site-footer {
    align-items: flex-start;
    flex-direction: column;
    gap: 20px;
  }
}

@media (max-width: 460px) {
  .hero h1 { font-size: 42px; }
  .hero-lead br { display: none; }
  .primary-cta { width: 100%; }
  .demo-label { margin-bottom: 28px; }
  .syntax-block { font-size: 18px; }
  .builder-sentence .syntax-block { font-size: 20px; }
  .builder-actions { flex-direction: column-reverse; }
  .text-button, .next-button { width: 100%; }
  .preposition-grid { grid-template-columns: 1fr; }
  .preposition-grid > div { border-right: 0; }
  .closing-steps p { grid-template-columns: 30px 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}