:root {
  --color-base: #ffffff;
  --color-main: #333333;
  --color-accent: #333333;
  --color-main-04: rgba(51, 51, 51, 0.04);
  --color-main-08: rgba(51, 51, 51, 0.08);
  --color-main-12: rgba(51, 51, 51, 0.12);
  --color-main-18: rgba(51, 51, 51, 0.18);
  --color-main-64: rgba(51, 51, 51, 0.64);
  --shadow-card: 0 2px 6px rgba(51, 51, 51, 0.06), 0 22px 54px rgba(51, 51, 51, 0.08);
  --shadow-card-hover: 0 2px 4px rgba(51, 51, 51, 0.08), 0 16px 32px rgba(51, 51, 51, 0.08);
  --font-body: "Noto Sans JP", sans-serif;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;
  --radius-card: 8px;
  --border: 1px solid var(--color-main-12);
  --container: 1440px;
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html {
  background: var(--color-base);
  color: var(--color-main);
  font-family: var(--font-body);
  font-weight: 400;
  letter-spacing: 0.05em;
  line-height: 1.7;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  background: var(--color-base);
  color: var(--color-main);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 400;
}

a {
  color: inherit;
  text-decoration: none;
}

button,
input {
  font: inherit;
}

button {
  min-height: 44px;
  cursor: pointer;
}

:focus-visible {
  outline: 3px solid var(--color-accent);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  left: var(--space-4);
  top: -80px;
  z-index: 20;
  min-height: 44px;
  padding: 10px 14px;
  background: var(--color-accent);
  color: var(--color-base);
}

.skip-link:focus-visible {
  top: var(--space-4);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1,
h2,
h3 {
  margin-bottom: 0;
  color: var(--color-main);
  line-height: 1.28;
  letter-spacing: 0;
}

h1 {
  max-width: 760px;
  font-size: 48px;
  font-weight: 700;
}

h2 {
  font-size: 32px;
  font-weight: 700;
}

h3 {
  font-size: 20px;
  font-weight: 700;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  background: rgba(255, 255, 255, 0.94);
  border-bottom: var(--border);
  backdrop-filter: blur(12px);
  transition: transform 180ms ease;
}

.top-nav {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  width: min(var(--container), calc(100% - 48px));
  margin: 0 auto;
  padding: var(--space-3) 0;
}

.brand-group {
  display: flex;
  flex: 1 1 auto;
  align-items: baseline;
  gap: var(--space-3);
  min-width: 0;
  margin-right: auto;
}

.brand {
  overflow: hidden;
  color: var(--color-main);
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.105em;
  line-height: 1.35;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.brand-byline {
  flex: 0 0 auto;
  color: var(--color-main-64);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.05em;
  line-height: 1.35;
}

.brand-byline:hover {
  color: var(--color-main);
  text-decoration: underline;
}

.header-nav {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: var(--space-5);
  color: var(--color-main-64);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.05em;
}

.header-nav a {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  color: var(--color-main-64);
}

.header-nav a:hover,
.header-nav-cta {
  color: var(--color-main);
  text-decoration: underline;
}

body.is-scrolling-down .site-header {
  transform: translateY(-100%);
}

body.is-scrolling-up .site-header {
  transform: translateY(0);
}

main {
  width: min(var(--container), calc(100% - 48px));
  margin: 0 auto;
}

.prompt-main {
  width: min(1180px, calc(100% - 48px));
}

.prompt-section {
  display: grid;
  gap: var(--space-5);
  padding: var(--space-8) 0;
}

.prompt-section h1 {
  max-width: none;
}

.content-tabs {
  display: inline-flex;
  width: fit-content;
  gap: var(--space-2);
  padding: var(--space-1);
  border: var(--border);
  border-radius: 999px;
  background: var(--color-main-04);
}

.content-tab {
  min-width: 128px;
  min-height: 44px;
  padding: 0 var(--space-4);
  border: var(--border);
  border-color: transparent;
  border-radius: 999px;
  background: transparent;
  color: var(--color-main);
  font-size: 14px;
  font-weight: 700;
}

.content-tab.is-active {
  border-color: var(--color-main-12);
  background: var(--color-base);
}

.prompt-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-4);
}

.prompt-card {
  display: grid;
  align-content: start;
  gap: var(--space-3);
  min-height: 0;
  padding: var(--space-4);
  border: 8px solid var(--color-base);
  border-radius: 34px;
  background: var(--color-base);
  box-shadow: var(--shadow-card);
  cursor: pointer;
  transition: box-shadow 160ms ease, transform 160ms ease;
}

.prompt-card:hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
}

.prompt-card h2 {
  padding-bottom: 0;
  border-bottom: 0;
  font-size: 20px;
  line-height: 1.35;
}

.prompt-card pre {
  display: none;
  margin: 0;
  overflow-x: auto;
  white-space: pre-wrap;
  word-break: break-word;
  color: var(--color-main);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.8;
  letter-spacing: 0;
}

.prompt-card-actions {
  display: flex;
  flex-wrap: nowrap;
  gap: var(--space-2);
  align-self: end;
  width: 100%;
  margin-top: var(--space-1);
}

.prompt-card-action,
.prompt-card-copy {
  flex: 1 1 0;
  width: auto;
  min-width: 0;
  min-height: 44px;
  padding: 0 var(--space-4);
  border: var(--border);
  border-radius: 999px;
  background: var(--color-base);
  color: var(--color-main);
  font-size: 14px;
  font-weight: 700;
  white-space: nowrap;
}

.prompt-card-copy {
  background: var(--color-base);
  color: var(--color-main);
}

.framework-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-5);
}

.framework-card {
  display: grid;
  align-content: start;
  gap: var(--space-4);
  min-height: 236px;
  padding: var(--space-5);
  border: 8px solid var(--color-base);
  border-radius: 34px;
  background: var(--color-base);
  box-shadow: var(--shadow-card);
  cursor: pointer;
  transition: box-shadow 160ms ease, transform 160ms ease;
}

.framework-card:hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
}

.framework-card span {
  color: var(--color-main-64);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.framework-card h2 {
  font-size: 20px;
}

.framework-card p {
  margin: 0;
  color: var(--color-main-64);
  font-size: 14px;
  line-height: 1.75;
}

.sales-letter-panel {
  display: grid;
  gap: var(--space-6);
}

.sales-letter-intro {
  display: grid;
  gap: var(--space-3);
  max-width: 840px;
  padding-bottom: var(--space-5);
  border-bottom: var(--border);
}

.sales-letter-intro h2 {
  font-size: 32px;
}

.sales-letter-intro p:last-child {
  margin: 0;
  color: var(--color-main-64);
  line-height: 1.8;
}

.sales-letter-flow {
  display: grid;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
}

.sales-letter-flow li {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: var(--space-5);
  padding: var(--space-6) 0;
  border-bottom: var(--border);
}

.sales-letter-flow li:first-child {
  padding-top: 0;
}

.sales-letter-flow li > span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border: var(--border);
  border-radius: 999px;
  color: var(--color-main-64);
  font-size: 14px;
  font-weight: 700;
  line-height: 1;
}

.sales-letter-flow div {
  display: grid;
  gap: var(--space-3);
}

.sales-letter-flow h3 {
  font-size: 24px;
}

.sales-letter-flow p {
  max-width: 840px;
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
}

.sales-letter-flow dl {
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: var(--space-2) var(--space-4);
  max-width: 920px;
  margin: var(--space-2) 0 0;
  padding: var(--space-4);
  border: var(--border);
  border-radius: var(--radius-card);
  background: var(--color-main-04);
}

.sales-letter-flow dt {
  color: var(--color-main-64);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.sales-letter-flow dd {
  margin: 0;
  line-height: 1.75;
}

.prompt-modal {
  position: relative;
  width: min(960px, calc(100% - 32px));
  max-height: min(820px, calc(100% - 32px));
  padding: 0;
  border: 0;
  border-radius: 34px;
  background: var(--color-base);
  color: var(--color-main);
  box-shadow: var(--shadow-card);
}

.modal-nav-button {
  position: absolute;
  top: 50%;
  z-index: 2;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  min-height: 44px;
  padding: 0;
  border: var(--border);
  border-radius: 999px;
  background: var(--color-base);
  color: var(--color-main);
  font-size: 28px;
  font-weight: 400;
  line-height: 1;
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-50%);
}

.modal-nav-button span {
  transform: translateY(-3px);
}

.modal-nav-prev {
  left: var(--space-4);
}

.modal-nav-next {
  right: var(--space-4);
}

.prompt-modal::backdrop {
  background: rgba(51, 51, 51, 0.18);
}

.modal-panel {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  max-height: min(820px, calc(100vh - 32px));
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-5) var(--space-6);
  border-bottom: var(--border);
}

.modal-header h2 {
  font-size: 24px;
}

.modal-close,
.copy-button {
  min-height: 44px;
  padding: 0 var(--space-4);
  border: var(--border);
  border-radius: 999px;
  background: var(--color-base);
  color: var(--color-main);
  font-size: 14px;
}

.copy-button {
  width: fit-content;
  margin: var(--space-5) var(--space-6);
  background: var(--color-base);
  color: var(--color-main);
  font-weight: 700;
}

#modal-body {
  display: grid;
  gap: var(--space-3);
  margin: 0;
  overflow: auto;
  padding: var(--space-6) var(--space-8);
  color: var(--color-main);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.8;
  letter-spacing: 0;
}

.modal-lead {
  margin-bottom: var(--space-5);
  padding: var(--space-4);
  border: var(--border);
  border-radius: var(--radius-card);
  background: var(--color-main-04);
  font-size: 18px;
  line-height: 1.7;
}

.modal-heading {
  margin: var(--space-5) 0 var(--space-2);
  padding: var(--space-4) 0 var(--space-2);
  border-bottom: var(--border);
  font-size: 20px;
}

.modal-line {
  margin: 0 0 var(--space-3);
  line-height: 1.85;
  word-break: break-word;
}

.modal-rule {
  width: 100%;
  height: 1px;
  margin: var(--space-5) 0;
  border: 0;
  background: var(--color-main-12);
}

.modal-step-line {
  padding: var(--space-3) var(--space-4);
  border-left: 4px solid var(--color-main);
  background: var(--color-main-04);
}

.modal-bullet {
  display: grid;
  grid-template-columns: 24px minmax(0, 1fr);
  gap: var(--space-2);
}

.modal-spacer {
  height: var(--space-3);
}

.modal-list {
  display: grid;
  gap: var(--space-3);
  margin: 0;
  padding: 0;
  list-style: none;
}

.modal-list li {
  padding-bottom: var(--space-3);
  border-bottom: var(--border);
}

.modal-step {
  display: grid;
  gap: var(--space-2);
  padding: var(--space-4);
  border: var(--border);
  border-radius: var(--radius-card);
  background: var(--color-main-04);
}

.modal-step span {
  display: block;
}

.modal-list strong,
.modal-lead strong,
.diagram-node strong,
.bar-row strong {
  font-weight: 700;
}

.modal-diagram {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  align-items: center;
  margin: 0 0 var(--space-5);
  padding: var(--space-4);
  border: var(--border);
  border-radius: var(--radius-card);
}

.diagram-node {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  padding: 0 var(--space-3);
  border: var(--border);
  border-radius: 999px;
  background: var(--color-base);
  font-size: 14px;
}

.diagram-arrow {
  color: var(--color-main-64);
  font-size: 16px;
  font-weight: 700;
}

.modal-bars {
  display: grid;
  gap: var(--space-3);
  margin: 0 0 var(--space-5);
  padding: var(--space-4);
  border: var(--border);
  border-radius: var(--radius-card);
}

.bar-row {
  display: grid;
  grid-template-columns: 120px minmax(0, 1fr);
  gap: var(--space-3);
  align-items: center;
  font-size: 14px;
}

.bar-row span {
  height: 12px;
  overflow: hidden;
  border: var(--border);
  border-radius: 999px;
  background: var(--color-main-04);
}

.bar-row i {
  display: block;
  height: 100%;
  background: var(--color-main);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 420px);
  gap: var(--space-8);
  align-items: end;
  min-height: min(720px, calc(100vh - 54px));
  padding: var(--space-7) 0 var(--space-7);
  border-bottom: var(--border);
}

.hero-copy {
  display: grid;
  gap: var(--space-5);
  align-content: end;
}

.eyebrow {
  margin: 0;
  color: var(--color-main-64);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.hero-lead,
.section-heading p {
  max-width: 760px;
  margin-bottom: 0;
  color: var(--color-main-64);
  font-size: 16px;
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 var(--space-5);
  border: var(--border);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 700;
}

.button-primary {
  background: var(--color-base);
  color: var(--color-main);
}

.button-secondary {
  background: var(--color-base);
  color: var(--color-main);
}

.hero-panel {
  padding: var(--space-6);
  border: 8px solid var(--color-base);
  border-radius: 34px;
  background: var(--color-base);
  box-shadow: var(--shadow-card);
}

.step-list {
  display: grid;
  gap: var(--space-5);
  margin: 0;
  padding: 0;
  list-style: none;
}

.step-list li {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: var(--space-4);
  align-items: start;
  min-height: 44px;
  padding-bottom: var(--space-4);
  border-bottom: var(--border);
  color: var(--color-main);
  font-size: 16px;
}

.step-list li:last-child {
  padding-bottom: 0;
  border-bottom: 0;
}

.step-list span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: var(--border);
  border-radius: 999px;
  color: var(--color-main-64);
  font-size: 12px;
}

.summary-band {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-4);
  padding: var(--space-7) 0;
  border-bottom: var(--border);
}

.summary-band article {
  display: grid;
  gap: var(--space-1);
  min-height: 112px;
  padding: var(--space-5);
  border: var(--border);
  border-radius: var(--radius-card);
}

.summary-band strong {
  font-size: 40px;
  line-height: 1;
}

.summary-band span {
  color: var(--color-main-64);
  font-size: 14px;
}

.learning-section,
.library-section,
.practice-section,
.check-section {
  padding: var(--space-8) 0;
  border-bottom: var(--border);
}

.section-heading {
  display: grid;
  gap: var(--space-3);
  margin-bottom: var(--space-6);
}

.principle-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-5);
}

.principle-card,
.lesson-card,
.pattern-card,
.check-card,
.practice-card {
  display: grid;
  align-content: start;
  gap: var(--space-4);
  min-width: 0;
  border: 8px solid var(--color-base);
  border-radius: 34px;
  background: var(--color-base);
  box-shadow: var(--shadow-card);
  color: var(--color-main);
  transition: box-shadow 160ms ease, transform 160ms ease;
}

.principle-card:hover,
.lesson-card:hover,
.pattern-card:hover,
.check-card:hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
}

.principle-card {
  min-height: 272px;
  padding: var(--space-6) var(--space-5) var(--space-5);
}

.principle-number,
.card-label {
  color: var(--color-main-64);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.principle-card p,
.lesson-card p,
.pattern-card p,
.check-card p,
.practice-card p,
.practice-card li {
  margin: 0;
  color: var(--color-main-64);
  font-size: 15px;
  line-height: 1.75;
}

.library-controls {
  position: sticky;
  top: 53px;
  z-index: 4;
  display: grid;
  gap: var(--space-4);
  margin-bottom: var(--space-5);
  padding: var(--space-4) 0;
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(12px);
  transition: transform 180ms ease;
}

body.is-scrolling-down .library-controls {
  transform: translateY(calc(-100% - 53px));
}

body.is-scrolling-up .library-controls {
  transform: translateY(0);
}

.tabs-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-5);
}

.tabs {
  display: inline-flex;
  gap: var(--space-2);
  padding: var(--space-1);
  border: var(--border);
  border-radius: 999px;
  background: var(--color-main-04);
}

.tab-button,
.filter-button,
.search-row button {
  min-height: 44px;
  border: var(--border);
  border-radius: 999px;
  background: var(--color-base);
  color: var(--color-main);
  cursor: pointer;
  font-size: 14px;
  font-weight: 400;
  white-space: nowrap;
}

.tab-button {
  min-width: 112px;
  padding: 0 var(--space-4);
  border-color: transparent;
  background: transparent;
}

.tab-button.is-active,
.filter-button.is-active {
  border-color: var(--color-main);
  background: var(--color-main);
  color: var(--color-base);
}

.filter-button:hover,
.search-row button:hover {
  border-color: var(--color-main);
}

.controls-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 360px);
  gap: var(--space-5);
  align-items: start;
}

.filters {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.filter-button {
  padding: 0 var(--space-4);
}

.search-panel {
  display: grid;
  gap: var(--space-2);
  padding: var(--space-4);
  border: var(--border);
  border-radius: 24px;
  background: var(--color-base);
  box-shadow: 0 1px 2px rgba(51, 51, 51, 0.04), 0 10px 24px rgba(51, 51, 51, 0.04);
}

.search-panel label {
  color: var(--color-main-64);
  font-size: 12px;
}

.search-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: var(--space-2);
}

.search-row input {
  width: 100%;
  min-width: 0;
  min-height: 44px;
  padding: 0 var(--space-4);
  border: var(--border);
  border-radius: 999px;
  background: var(--color-base);
  color: var(--color-main);
}

.search-row input::placeholder {
  color: var(--color-main-64);
}

.search-row button {
  padding: 0 var(--space-4);
}

.card-grid,
.pattern-grid,
.check-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-5);
}

.lesson-card,
.pattern-card,
.check-card {
  min-height: 292px;
  padding: var(--space-5);
}

.lesson-card h3,
.pattern-card h3,
.check-card h3 {
  overflow-wrap: anywhere;
}

.formula {
  margin: auto 0 0;
  padding: var(--space-3);
  border: var(--border);
  border-radius: 6px;
  background: var(--color-main-04);
  color: var(--color-main);
  font-size: 14px;
  line-height: 1.75;
}

.practice-layout {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-5);
}

.practice-card {
  min-height: 240px;
  padding: var(--space-5);
}

.practice-card ul {
  display: grid;
  gap: var(--space-2);
  margin: 0;
  padding-left: 1.2em;
}

.practice-card-wide {
  background: var(--color-main);
  color: var(--color-base);
}

.practice-card-wide h3,
.practice-card-wide p {
  color: var(--color-base);
}

.score-form {
  display: grid;
  gap: var(--space-3);
  max-width: 760px;
}

.score-form label {
  display: grid;
  grid-template-columns: 24px minmax(0, 1fr);
  gap: var(--space-3);
  align-items: center;
  min-height: 48px;
  padding: var(--space-3) var(--space-4);
  border: var(--border);
  border-radius: var(--radius-card);
  font-size: 16px;
}

.score-form input {
  width: 20px;
  height: 20px;
  accent-color: var(--color-main);
}

.score-output {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: fit-content;
  min-height: 48px;
  margin-top: var(--space-2);
  padding: 0 var(--space-5);
  border-radius: 999px;
  background: var(--color-main);
  color: var(--color-base);
  font-size: 20px;
  font-weight: 700;
}

.empty-state {
  margin: var(--space-5) 0 0;
  padding: var(--space-4);
  border: var(--border);
  border-radius: var(--radius-card);
  background: var(--color-main-04);
  color: var(--color-main-64);
}

.site-footer {
  width: min(var(--container), calc(100% - 48px));
  margin: 0 auto;
  padding: var(--space-6) 0;
  color: var(--color-main-64);
  font-size: 12px;
  line-height: 1.8;
}

.site-footer p {
  max-width: 880px;
  margin: 0;
}

@media (max-width: 1200px) {
  .framework-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .principle-grid,
  .summary-band {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 960px) {
  .top-nav {
    align-items: flex-start;
    flex-wrap: wrap;
    gap: var(--space-2) var(--space-3);
  }

  .header-nav {
    order: 3;
    width: 100%;
    gap: var(--space-5);
    overflow-x: auto;
  }

  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .library-controls {
    position: static;
  }

  body.is-scrolling-down .library-controls,
  body.is-scrolling-up .library-controls {
    transform: none;
  }

  .tabs-row,
  .controls-row {
    display: grid;
    grid-template-columns: 1fr;
  }

  .card-grid,
  .pattern-grid,
  .check-grid,
  .practice-layout,
  .framework-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 620px) {
  main,
  .top-nav,
  .site-footer {
    width: min(100% - 32px, var(--container));
  }

  .site-header {
    position: static;
  }

  h1 {
    font-size: 36px;
  }

  h2 {
    font-size: 28px;
  }

  .brand-group {
    flex: 1 1 180px;
    flex-wrap: wrap;
  }

  .brand {
    white-space: normal;
  }

  .hero,
  .learning-section,
  .library-section,
  .practice-section,
  .check-section {
    padding: var(--space-7) 0;
  }

  .tabs {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    width: 100%;
  }

  .tab-button {
    min-width: 0;
    padding: 0 var(--space-2);
  }

  .search-row {
    grid-template-columns: 1fr;
  }

  .principle-grid,
  .summary-band,
  .card-grid,
  .pattern-grid,
  .check-grid,
  .practice-layout,
  .prompt-list,
  .framework-grid {
    grid-template-columns: 1fr;
  }

  .principle-card,
  .lesson-card,
  .pattern-card,
  .check-card,
  .practice-card,
  .hero-panel {
    min-height: auto;
    border-radius: 28px;
  }

  .prompt-card {
    min-height: auto;
    padding: var(--space-5);
    border-radius: 28px;
  }

  .content-tabs {
    display: grid;
    grid-template-columns: 1fr;
    width: 100%;
  }

  .content-tab {
    min-width: 0;
  }

  .prompt-card h2 {
    font-size: 20px;
  }

  .prompt-card-action,
  .prompt-card-copy {
    padding: 0 var(--space-4);
    font-size: 14px;
  }

  .framework-card {
    min-height: auto;
    border-radius: 28px;
  }

  .sales-letter-intro h2 {
    font-size: 24px;
  }

  .sales-letter-flow li {
    grid-template-columns: 1fr;
    gap: var(--space-3);
    padding: var(--space-5) 0;
  }

  .sales-letter-flow h3 {
    font-size: 20px;
  }

  .sales-letter-flow dl {
    grid-template-columns: 1fr;
  }

  .modal-header {
    align-items: flex-start;
    flex-direction: column;
    padding: var(--space-5);
  }

  .modal-header h2 {
    font-size: 20px;
  }

  #modal-body {
    padding: var(--space-5);
    font-size: 15px;
  }

  .bar-row {
    grid-template-columns: 1fr;
  }

  .modal-diagram {
    display: grid;
  }

  .diagram-arrow {
    transform: rotate(90deg);
    justify-self: center;
  }

  .copy-button {
    margin: var(--space-5);
  }
}

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