.usage-body {
  --usage-accent: #0d7063;
  --usage-accent-soft: #eaf5f2;
  --usage-accent-line: #bcded6;
  background:
    radial-gradient(circle at 78% 5%, rgba(15, 111, 98, 0.08), transparent 28rem),
    var(--background);
}

:root[data-theme="dark"] .usage-body {
  --usage-accent: #79d0be;
  --usage-accent-soft: rgba(61, 170, 146, 0.11);
  --usage-accent-line: rgba(121, 208, 190, 0.28);
}

.usage-main {
  padding-top: var(--header-height);
}

.usage-hero {
  width: min(calc(100% - 40px), var(--container));
  margin-inline: auto;
  padding: 88px 0 72px;
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(330px, 0.85fr);
  align-items: end;
  gap: clamp(48px, 8vw, 104px);
  border-bottom: 1px solid var(--border);
}

.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 9px;
  color: var(--text-muted);
  font-size: 13px;
}

.breadcrumbs a {
  transition: color 150ms ease;
}

.breadcrumbs a:hover,
.breadcrumbs a:focus-visible {
  color: var(--text);
}

.usage-kicker,
.section-overline {
  margin: 0;
  color: var(--usage-accent);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.usage-kicker {
  margin-top: 42px;
}

.usage-hero h1 {
  max-width: 740px;
  margin: 12px 0 20px;
  font-size: clamp(42px, 5.3vw, 72px);
  font-weight: 650;
  line-height: 1.2;
}

.usage-lead {
  max-width: 740px;
  margin: 0;
  color: var(--text-secondary);
  font-size: clamp(18px, 2vw, 22px);
  line-height: 2;
}

.usage-principles {
  padding: 8px 0;
  display: grid;
  gap: 0;
  border-block: 1px solid var(--border);
}

.principle {
  min-height: 92px;
  padding: 19px 0;
  display: flex;
  align-items: center;
  gap: 16px;
}

.principle + .principle {
  border-top: 1px solid var(--border);
}

.principle-icon,
.section-icon {
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  border: 1px solid var(--usage-accent-line);
  color: var(--usage-accent);
  background: var(--usage-accent-soft);
}

.principle-icon {
  width: 42px;
  height: 42px;
  border-radius: 50%;
}

.principle-icon svg {
  width: 19px;
  height: 19px;
}

.principle div {
  display: grid;
  gap: 2px;
}

.principle strong {
  font-size: 15px;
  font-weight: 650;
}

.principle span:last-child {
  color: var(--text-secondary);
  font-size: 13px;
}

.usage-layout {
  width: min(calc(100% - 40px), var(--container));
  margin-inline: auto;
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: clamp(56px, 9vw, 124px);
}

.usage-toc {
  position: relative;
}

.usage-toc-inner {
  position: sticky;
  top: calc(var(--header-height) + 34px);
  padding-top: 78px;
}

.usage-toc p {
  margin: 0 0 14px;
  color: var(--text);
  font-size: 13px;
  font-weight: 650;
}

.usage-toc nav {
  display: grid;
  border-inline-start: 1px solid var(--border);
}

.usage-toc a {
  margin-inline-start: -1px;
  padding: 6px 17px 6px 6px;
  border-inline-start: 1px solid transparent;
  color: var(--text-muted);
  font-size: 13px;
  line-height: 1.55;
  transition: color 150ms ease, border-color 150ms ease;
}

.usage-toc a:hover,
.usage-toc a:focus-visible {
  border-color: var(--usage-accent);
  color: var(--text);
}

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

.usage-section {
  padding: 80px 0;
  border-bottom: 1px solid var(--border);
}

.section-heading-row {
  margin-bottom: 28px;
  display: flex;
  align-items: flex-start;
  gap: 18px;
}

.section-icon {
  width: 44px;
  height: 44px;
  border-radius: 11px;
}

.section-icon svg {
  width: 21px;
  height: 21px;
}

.usage-section h2,
.usage-change-note h2,
.usage-cta h2 {
  margin: 5px 0 0;
  font-size: clamp(28px, 3.4vw, 40px);
  font-weight: 640;
  line-height: 1.45;
}

.usage-section > p {
  max-width: 800px;
  margin: 0 0 26px;
  color: var(--text-secondary);
  font-size: 18px;
  line-height: 2.05;
}

.plain-grid {
  margin-top: 34px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.plain-card {
  min-height: 154px;
  padding: 25px;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: var(--surface-raised);
}

.plain-card strong {
  font-size: 16px;
  font-weight: 650;
}

.plain-card p {
  margin: 9px 0 0;
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.85;
}

.reference-note {
  margin-top: 20px;
  padding: 22px 24px;
  display: flex;
  align-items: flex-start;
  gap: 14px;
  border: 1px solid var(--usage-accent-line);
  border-radius: 12px;
  background: var(--usage-accent-soft);
}

.reference-note > svg {
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  margin-top: 3px;
  color: var(--usage-accent);
}

.reference-note p {
  margin: 0;
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.85;
}

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

.model-list {
  margin: 34px 0 20px;
  display: grid;
  border-top: 1px solid var(--border);
}

.model-row {
  min-height: 128px;
  padding: 24px 0;
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr);
  align-items: center;
  gap: 22px;
  border-bottom: 1px solid var(--border);
}

.model-mark {
  width: 54px;
  height: 54px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border-strong);
  border-radius: 50%;
  background: var(--surface);
  font-family: ui-monospace, "SFMono-Regular", Menlo, monospace;
  font-size: 16px;
  font-weight: 700;
  direction: ltr;
}

.model-row h3 {
  margin: 0 0 5px;
  font-size: 21px;
  font-weight: 650;
}

.model-row p {
  margin: 0;
  color: var(--text-secondary);
  font-size: 15px;
}

.muted-callout {
  padding-inline-start: 20px;
  border-inline-start: 2px solid var(--usage-accent);
  color: var(--text-secondary) !important;
  font-size: 15px !important;
  line-height: 1.9 !important;
}

.subheading {
  margin: 52px 0 12px;
  font-size: 23px;
  font-weight: 650;
}

.before-after {
  margin: 36px 0 22px;
  padding: 30px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 44px minmax(0, 1fr);
  gap: 20px;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--surface);
}

.phase-label {
  display: inline-flex;
  padding: 4px 9px;
  border: 1px solid var(--usage-accent-line);
  border-radius: 999px;
  color: var(--usage-accent);
  background: var(--usage-accent-soft);
  font-size: 11px;
  font-weight: 700;
}

.before-after h3 {
  margin: 14px 0 7px;
  font-size: 20px;
  font-weight: 650;
}

.before-after p {
  margin: 0;
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.85;
}

.phase-arrow {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border);
  border-radius: 50%;
  color: var(--text-muted);
  background: var(--surface-raised);
  transform: rotate(180deg);
}

.phase-arrow svg {
  width: 17px;
  height: 17px;
}

.charge-flow {
  margin: 38px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  list-style: none;
  counter-reset: charge-step;
}

.charge-flow li {
  position: relative;
  min-height: 150px;
  padding: 54px 0 0 18px;
  counter-increment: charge-step;
  border-top: 1px solid var(--border-strong);
}

.charge-flow li::before {
  content: counter(charge-step, arabic-indic);
  position: absolute;
  top: -18px;
  inset-inline-start: 0;
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border-strong);
  border-radius: 50%;
  color: var(--text-secondary);
  background: var(--background);
  font-size: 12px;
  font-weight: 650;
}

.charge-flow li:last-child::before {
  border-color: var(--usage-accent);
  color: var(--usage-accent);
  background: var(--usage-accent-soft);
}

.charge-flow span,
.charge-flow small {
  display: block;
}

.charge-flow span {
  font-size: 14px;
  font-weight: 650;
}

.charge-flow small {
  margin-top: 5px;
  color: var(--text-muted);
  font-size: 12px;
  line-height: 1.65;
}

.no-charge-list {
  margin: 34px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  list-style: none;
}

.no-charge-list li {
  min-height: 134px;
  padding: 22px;
  display: flex;
  align-items: flex-start;
  gap: 12px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface-raised);
}

.no-charge-list svg {
  flex: 0 0 auto;
  width: 19px;
  height: 19px;
  margin-top: 3px;
  color: var(--usage-accent);
}

.no-charge-list span {
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.8;
}

.no-charge-list strong {
  color: var(--text);
  font-weight: 650;
}

.recovery-grid {
  margin: 34px 0 20px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: var(--border);
}

.recovery-grid div {
  min-height: 178px;
  padding: 24px;
  background: var(--surface-raised);
}

.recovery-grid strong {
  font-size: 15px;
  font-weight: 650;
}

.recovery-grid p {
  margin: 10px 0 0;
  color: var(--text-secondary);
  font-size: 13px;
  line-height: 1.85;
}

.reference-note-dark {
  border-color: var(--border-strong);
  background: var(--surface);
}

.limits-table {
  margin-top: 34px;
  border-top: 1px solid var(--border-strong);
}

.limits-head,
.limits-row {
  display: grid;
  grid-template-columns: 0.72fr 1fr 1.35fr;
  gap: 24px;
  align-items: start;
  border-bottom: 1px solid var(--border);
}

.limits-head {
  padding: 12px 0;
  color: var(--text-muted);
  font-size: 11px;
  font-weight: 650;
}

.limits-row {
  padding: 24px 0;
}

.limits-row strong {
  color: var(--text);
  font-size: 14px;
  font-weight: 650;
}

.limits-row span {
  color: var(--text-secondary);
  font-size: 13px;
  line-height: 1.75;
}

.usage-faq {
  margin-top: 34px;
}

.usage-faq details {
  border-color: var(--border);
  background: transparent;
}

.usage-faq details:first-child {
  border-top: 1px solid var(--border);
}

.usage-faq summary {
  padding-inline: 0 44px;
  font-size: 17px;
}

.usage-faq details p {
  padding-inline: 0 44px;
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.9;
}

.usage-change-note {
  margin: 80px 0 0;
  padding: 42px;
  border: 1px solid var(--border-strong);
  border-radius: 16px;
  background: var(--surface);
}

.usage-change-note h2 {
  max-width: 720px;
  font-size: clamp(26px, 3vw, 36px);
}

.usage-change-note > p:last-child {
  max-width: 800px;
  margin: 19px 0 0;
  color: var(--text-secondary);
  font-size: 16px;
  line-height: 1.95;
}

.usage-cta {
  margin: 18px 0 96px;
  padding: 38px 42px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  border-radius: 16px;
  color: var(--on-brand);
  background: var(--brand);
}

.usage-cta .section-overline {
  color: currentColor;
  opacity: 0.62;
}

.usage-cta h2 {
  font-size: clamp(25px, 3vw, 34px);
}

.usage-cta p:last-child {
  margin: 10px 0 0;
  color: currentColor;
  opacity: 0.72;
  font-size: 14px;
}

.usage-cta .button-primary {
  flex: 0 0 auto;
  border-color: var(--on-brand);
  color: var(--brand);
  background: var(--on-brand);
}

.usage-footer {
  border-top: 1px solid var(--border);
}

@media (max-width: 1020px) {
  .usage-hero {
    padding-top: 64px;
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .usage-principles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    border: 1px solid var(--border);
    border-radius: 13px;
  }

  .principle {
    min-height: 150px;
    padding: 22px;
    align-items: flex-start;
    flex-direction: column;
  }

  .principle + .principle {
    border-top: 0;
    border-inline-start: 1px solid var(--border);
  }

  .usage-layout {
    grid-template-columns: 1fr;
    gap: 0;
  }

  .usage-toc {
    display: none;
  }

  .usage-content {
    width: min(100%, 820px);
    margin-inline: auto;
  }

  .recovery-grid {
    grid-template-columns: 1fr;
  }

  .recovery-grid div {
    min-height: auto;
  }
}

@media (max-width: 720px) {
  .usage-main {
    padding-top: var(--header-height);
  }

  .usage-hero,
  .usage-layout {
    width: calc(100% - 32px);
  }

  .usage-hero {
    padding: 42px 0 46px;
  }

  .usage-kicker {
    margin-top: 30px;
  }

  .usage-hero h1 {
    margin-top: 10px;
    font-size: 40px;
  }

  .usage-lead {
    font-size: 17px;
    line-height: 1.9;
  }

  .usage-principles {
    grid-template-columns: 1fr;
  }

  .principle {
    min-height: auto;
    padding: 18px;
    flex-direction: row;
    align-items: center;
  }

  .principle + .principle {
    border-inline-start: 0;
    border-top: 1px solid var(--border);
  }

  .usage-section {
    padding: 58px 0;
  }

  .section-heading-row {
    gap: 13px;
  }

  .section-icon {
    width: 40px;
    height: 40px;
  }

  .usage-section h2,
  .usage-change-note h2,
  .usage-cta h2 {
    font-size: 28px;
  }

  .usage-section > p {
    font-size: 16px;
    line-height: 1.95;
  }

  .plain-grid,
  .no-charge-list {
    grid-template-columns: 1fr;
  }

  .plain-card,
  .no-charge-list li {
    min-height: auto;
  }

  .reference-note {
    padding: 19px;
  }

  .model-row {
    grid-template-columns: 48px minmax(0, 1fr);
    gap: 16px;
  }

  .model-mark {
    width: 48px;
    height: 48px;
  }

  .before-after {
    padding: 22px;
    grid-template-columns: 1fr;
  }

  .phase-arrow {
    transform: rotate(90deg);
  }

  .charge-flow {
    margin-inline-start: 17px;
    grid-template-columns: 1fr;
  }

  .charge-flow li {
    min-height: 108px;
    padding: 0 52px 28px 0;
    border-top: 0;
    border-inline-start: 1px solid var(--border-strong);
  }

  .charge-flow li::before {
    top: -1px;
    inset-inline-start: -18px;
  }

  .charge-flow li:last-child {
    min-height: auto;
    padding-bottom: 0;
    border-color: transparent;
  }

  .limits-head {
    display: none;
  }

  .limits-table {
    display: grid;
    gap: 12px;
    border-top: 0;
  }

  .limits-row {
    padding: 20px;
    display: grid;
    grid-template-columns: 1fr;
    gap: 8px;
    border: 1px solid var(--border);
    border-radius: 11px;
    background: var(--surface-raised);
  }

  .limits-row span:last-child {
    padding-top: 8px;
    border-top: 1px solid var(--border);
  }

  .usage-faq summary,
  .usage-faq details p {
    padding-inline-start: 0;
    padding-inline-end: 36px;
  }

  .usage-change-note {
    margin-top: 58px;
    padding: 28px 22px;
  }

  .usage-cta {
    margin-bottom: 72px;
    padding: 30px 22px;
    align-items: flex-start;
    flex-direction: column;
  }
}

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

@media print {
  .usage-body {
    background: #fff;
  }

  .usage-body .site-header,
  .usage-body .usage-toc,
  .usage-body .usage-cta,
  .usage-body .site-footer {
    display: none !important;
  }

  .usage-main {
    padding-top: 0;
  }

  .usage-hero,
  .usage-layout {
    width: 100%;
  }

  .usage-hero {
    padding: 0 0 30px;
    grid-template-columns: 1fr;
  }

  .usage-principles {
    display: none;
  }

  .usage-section,
  .usage-change-note {
    break-inside: avoid;
  }
}