.hero {
  position: relative;
  overflow-x: clip;
  padding-top: 38px;
  padding-bottom: 30px;
  text-align: center;
}

.hero-title {
  margin: 12px auto 0;
  max-width: 980px;
}

.hero-description {
  max-width: 850px;
  margin: 18px auto 0;
  color: var(--color-muted);
  font-size: clamp(15px, 1.5vw, 17px);
}

.hero-description strong {
  color: var(--color-text);
  font-weight: 650;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px;
  margin-top: 22px;
}

.trust-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-top: 16px;
}

.lecture-card {
  width: min(960px, 100%);
  margin: 28px auto 0;
  padding: 24px 56px 22px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-m);
  background: var(--color-panel);
  box-shadow: var(--shadow-card);
  text-align: left;
}

.lecture-head {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 13px;
  border-bottom: 1px dashed var(--color-border);
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
}

.hero-formula {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: .28em;
  margin-top: 26px;
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: clamp(72px, 9vw, 124px);
  font-weight: 800;
  letter-spacing: -.01em;
  line-height: 1;
}

.formula-operator {
  color: var(--color-muted);
  font-size: .72em;
  font-weight: 700;
  transform: translateY(-.06em);
}

.formula-dot {
  color: var(--color-accent);
  font-size: .9em;
  transform: none;
}

.formula-annotations {
  display: flex;
  justify-content: center;
  gap: 76px;
  margin-top: 20px;
}

.formula-annotation {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.formula-annotation svg {
  flex: 0 0 auto;
}

.arrow-line {
  stroke: var(--color-accent);
}

.arrow-head {
  fill: var(--color-accent);
}

.annotation-copy {
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 12.5px;
}

.annotation-copy b {
  margin-right: 6px;
  color: var(--color-text);
}

.ruler-caption {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 28px;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .1em;
}

.formula-ruler {
  width: 100%;
  margin-top: 6px;
}

.ruler-line,
.ruler-major {
  fill: none;
  stroke: var(--color-text);
}

.ruler-minor {
  fill: none;
  stroke: var(--color-muted);
}

.ruler-text {
  fill: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 10px;
}

.hero-footnotes {
  display: grid;
  width: min(960px, 100%);
  gap: 11px;
  margin: 22px auto 0;
}

.footnote-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 20px;
}

.footnote-key {
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
}

.platform-mark,
.flag-mark {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  color: var(--color-muted);
  font-size: 12.5px;
}

.platform-mark svg,
.flag-mark svg {
  flex: 0 0 auto;
}

.flag-base {
  fill: var(--color-panel);
}

.flag-tint {
  fill: var(--color-flag-tint);
}

.flag-frame {
  fill: none;
  stroke: var(--color-border);
}

.flag-ink {
  fill: var(--color-flag-ink);
}

.flag-line {
  fill: none;
  stroke: var(--color-flag-ink);
}

.theorem-list {
  border-top: 1px solid var(--color-border);
}

.theorem-row {
  position: relative;
  display: grid;
  grid-template-columns: minmax(180px, .7fr) minmax(0, 1.4fr);
  gap: clamp(28px, 6vw, 90px);
  padding: 34px 8px;
  border-bottom: 1px solid var(--color-border);
}

.theorem-row::before {
  position: absolute;
  top: 43px;
  left: -18px;
  width: 10px;
  height: 8px;
  opacity: 0;
  background: var(--color-accent);
  clip-path: polygon(0 0, 100% 50%, 0 100%);
  content: "";
  transition: opacity var(--motion-fast), transform var(--motion-fast);
  transform: translateX(-5px);
}

.theorem-row:hover::before {
  opacity: 1;
  transform: none;
}

.theorem-heading {
  display: flex;
  gap: 14px;
  align-items: baseline;
}

.theorem-number {
  flex: 0 0 auto;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
}

.theorem-row:hover .theorem-number {
  color: var(--color-accent);
}

.theorem-heading h3 {
  margin: 0;
  font-size: 19px;
}

.theorem-row p {
  margin: 0;
  color: var(--color-muted);
  font-size: 14px;
}

.tabs {
  min-width: 0;
}

.tab-list {
  display: flex;
  max-width: 100%;
  gap: 6px;
  overflow-x: auto;
  padding: 5px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-s);
  background: var(--color-panel-soft);
  scrollbar-width: thin;
}

.tab-list [role="tab"] {
  min-height: 42px;
  flex: 0 0 auto;
  padding: 8px 18px;
  border: 1px solid transparent;
  border-radius: var(--radius-xs);
  background: transparent;
  color: var(--color-muted);
  font-weight: 650;
}

.tab-list [role="tab"][aria-selected="true"] {
  border-color: var(--color-border);
  background: var(--color-panel);
  box-shadow: var(--shadow-button);
  color: var(--color-text);
}

[role="tabpanel"][hidden] {
  display: none;
}

.tab-panel {
  padding-top: 24px;
}

.toc-tabs {
  position: sticky;
  top: 0;
  z-index: 70;
  display: flex;
  max-width: 100%;
  gap: 3px;
  overflow-x: auto;
  padding: 7px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-s);
  background: var(--color-panel);
  box-shadow: var(--shadow-button);
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}

.toc-tabs a {
  min-height: 38px;
  flex: 0 0 auto;
  padding: 7px 13px;
  border-radius: var(--radius-xs);
  color: var(--color-muted);
  font-size: 13px;
  white-space: nowrap;
}

.toc-tabs a:hover,
.toc-tabs a.toc-current {
  background: var(--color-panel-soft);
  color: var(--color-text);
}

.toc-tabs a.toc-current {
  box-shadow: inset 0 -2px var(--color-accent);
  font-weight: 700;
}

.faq-list {
  border-top: 1px solid var(--color-border);
}

.faq-item {
  border-bottom: 1px solid var(--color-border);
}

.faq-item summary {
  position: relative;
  display: flex;
  min-height: 64px;
  align-items: center;
  padding: 16px 44px 16px 0;
  color: var(--color-text);
  font-weight: 680;
  list-style: none;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  position: absolute;
  right: 6px;
  color: var(--color-accent);
  content: "+";
  font-family: var(--font-mono);
  font-size: 22px;
  transition: transform var(--motion-fast);
}

.faq-item[open] summary::after {
  transform: rotate(45deg);
}

.faq-answer {
  max-width: 820px;
  padding: 0 44px 20px 0;
  color: var(--color-muted);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.plan-card {
  position: relative;
  display: flex;
  min-width: 0;
  flex-direction: column;
  padding: 28px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-m);
  background: var(--color-panel);
}

.plan-card.is-featured {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-card);
}

.plan-card.is-current {
  box-shadow: inset 0 3px var(--color-accent), var(--shadow-card);
}

.plan-ribbon {
  position: absolute;
  top: 14px;
  right: 14px;
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .08em;
}

.plan-card h3 {
  padding-right: 64px;
}

.plan-price {
  display: flex;
  align-items: baseline;
  gap: 5px;
  margin: 14px 0;
  font-family: var(--font-mono);
}

.plan-price strong {
  font-size: 38px;
  line-height: 1;
}

.plan-price span {
  color: var(--color-muted);
  font-size: 13px;
}

.plan-features {
  flex: 1;
  margin: 10px 0 24px;
  padding-left: 1.2em;
  color: var(--color-muted);
  font-size: 14px;
}

.table-scroll {
  width: 100%;
  max-width: 100%;
  overflow-x: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-s);
  background: var(--color-panel);
  overscroll-behavior-inline: contain;
  -webkit-overflow-scrolling: touch;
}

.data-table,
.location-table,
.comparison-table {
  width: 100%;
  min-width: 720px;
  border-collapse: collapse;
  background: var(--color-panel);
  color: var(--color-text);
}

.data-table th,
.data-table td,
.location-table th,
.location-table td,
.comparison-table th,
.comparison-table td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--color-border);
  text-align: left;
  vertical-align: top;
}

.data-table th,
.location-table th,
.comparison-table th {
  background: var(--color-panel-soft);
  color: var(--color-text);
  font-size: 12px;
  font-weight: 750;
  letter-spacing: .05em;
}

.data-table td,
.location-table td,
.comparison-table td {
  font-size: 14px;
}

.location-table .region-row th {
  background: var(--color-panel);
  color: var(--color-accent-dark);
  font-family: var(--font-mono);
}

.table-status {
  color: var(--color-success);
  font-weight: 700;
}

.platform-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 14px;
}

.platform-card {
  display: flex;
  min-width: 0;
  flex-direction: column;
  align-items: flex-start;
  gap: 14px;
  padding: 22px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-s);
  background: var(--color-panel);
}

.platform-icon {
  display: grid;
  width: 42px;
  height: 42px;
  flex: 0 0 auto;
  place-items: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-s);
  color: var(--color-text);
}

.platform-icon svg {
  width: 23px;
  height: 23px;
}

.platform-card h3 {
  margin: 0;
  font-size: 17px;
}

.platform-card p {
  flex: 1;
  margin: 0;
  color: var(--color-muted);
  font-size: 13px;
}

.article-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.article-card {
  display: flex;
  min-width: 0;
  flex-direction: column;
  padding: 24px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-s);
  background: var(--color-panel);
  transition: border-color var(--motion-fast), transform var(--motion-fast);
}

.article-card:hover {
  border-color: var(--color-muted);
  transform: translateY(-2px);
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 15px;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 11px;
}

.article-card h3 {
  font-size: 20px;
}

.article-card p {
  flex: 1;
  color: var(--color-muted);
  font-size: 14px;
}

.callout {
  position: relative;
  margin: 24px 0;
  padding: 20px 22px 20px 26px;
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-accent);
  border-radius: var(--radius-s);
  background: var(--color-panel-soft);
  color: var(--color-muted);
}

.callout strong {
  color: var(--color-text);
}

.end-promo {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 28px;
  align-items: center;
  margin-top: 48px;
  padding: clamp(24px, 4vw, 42px);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-m);
  background: var(--color-panel);
  box-shadow: var(--shadow-card);
}

.article-body .end-promo h2 {
  margin-bottom: 8px;
  color: var(--color-text);
  font-size: clamp(26px, 3vw, 38px);
}

.article-body .end-promo p {
  margin: 0;
  color: var(--color-muted);
}

.float-cta {
  position: fixed;
  right: 28px;
  bottom: calc(28px + env(safe-area-inset-bottom, 0px));
  z-index: 90;
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  gap: 8px;
  padding: 9px 20px;
  border-radius: var(--radius-s);
  background: var(--color-accent);
  box-shadow: var(--shadow-float);
  color: var(--color-panel);
  font-size: 14px;
  font-weight: 700;
}

.float-cta:hover {
  background: var(--color-accent-dark);
}

.float-cta svg {
  width: 16px;
  height: 16px;
  flex: 0 0 auto;
}

body:has(.float-cta)::after {
  display: block;
  height: calc(88px + env(safe-area-inset-bottom, 0px));
  content: "";
}

.preview-block {
  padding-top: 76px;
  padding-bottom: 76px;
  border-top: 1px solid var(--color-border);
}

.preview-heading {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin-bottom: 30px;
}

.preview-heading .section-number {
  color: var(--color-accent);
  font-size: 12px;
}

.preview-heading h2 {
  margin: 0;
  font-size: clamp(28px, 4vw, 42px);
}

.preview-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.preview-stack {
  display: grid;
  gap: 20px;
}

.swatch-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 12px;
}

.swatch {
  min-width: 0;
  overflow: hidden;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-s);
  background: var(--color-panel);
}

.swatch-color {
  height: 78px;
  border-bottom: 1px solid var(--color-border);
}

.swatch-bg {
  background: var(--color-bg);
}

.swatch-panel {
  background: var(--color-panel);
}

.swatch-soft {
  background: var(--color-panel-soft);
}

.swatch-border {
  background: var(--color-border);
}

.swatch-accent {
  background: var(--color-accent);
}

.swatch-accent-dark {
  background: var(--color-accent-dark);
}

.swatch-text {
  background: var(--color-text);
}

.swatch-muted {
  background: var(--color-muted);
}

.swatch-success {
  background: var(--color-success);
}

.swatch-warning {
  background: var(--color-warning);
}

.swatch-error {
  background: var(--color-error);
}

.swatch-label {
  display: grid;
  gap: 2px;
  padding: 11px;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 10px;
  overflow-wrap: anywhere;
}

.type-sample {
  padding: 26px;
  border-top: 1px solid var(--color-border);
}

.type-sample:first-child {
  border-top: 0;
}

.type-sample-display {
  font-family: var(--font-display);
  font-size: clamp(36px, 5vw, 64px);
  font-weight: 800;
  letter-spacing: -.02em;
  line-height: 1.1;
}

.type-sample-body {
  max-width: 680px;
  color: var(--color-muted);
}

.type-sample-mono {
  font-family: var(--font-mono);
  font-size: 14px;
}

.button-demo {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.static-footer {
  margin-top: 0;
}

@media (max-width: 900px) {
  .pricing-grid,
  .article-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .platform-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .swatch-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 768px) {
  .hero {
    padding-top: 30px;
  }

  .lecture-card {
    padding: 20px;
  }

  .lecture-head {
    align-items: flex-start;
    flex-direction: column;
    gap: 5px;
  }

  .hero-formula {
    font-size: clamp(52px, 18vw, 82px);
  }

  .formula-annotations {
    align-items: center;
    flex-direction: column;
    gap: 14px;
  }

  .ruler-caption {
    align-items: flex-start;
    flex-direction: column;
    gap: 3px;
  }

  .theorem-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 14px;
  }

  .end-promo {
    grid-template-columns: minmax(0, 1fr);
  }

  .preview-grid {
    grid-template-columns: minmax(0, 1fr);
  }
}

@media (max-width: 640px) {
  .cta-row {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
  }

  .cta-row .btn {
    width: 100%;
  }

  .footnote-row {
    gap: 12px 16px;
  }

  .footnote-key {
    width: 100%;
  }

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

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

  .float-cta {
    right: 16px;
    bottom: calc(16px + env(safe-area-inset-bottom, 0px));
  }
}