:root {
  color-scheme: light;
  --ink: #172126;
  --muted: #5b6870;
  --line: #d9e2e7;
  --paper: #f7faf8;
  --panel: #ffffff;
  --panel-soft: #eef7f1;
  --brand: #1f7a5b;
  --brand-dark: #13533d;
  --accent: #f2b84b;
  --code-bg: #10221b;
  --code-ink: #f6fff9;
  --shadow: 0 18px 45px rgba(23, 33, 38, 0.07);
}

html[data-theme="dark"] {
  color-scheme: dark;
  --ink: #ecf4ef;
  --muted: #aab8b1;
  --line: #29433a;
  --paper: #0d1714;
  --panel: #14231e;
  --panel-soft: #19362d;
  --brand: #73d9a8;
  --brand-dark: #b1f2cf;
  --accent: #f5c76d;
  --code-bg: #07100d;
  --code-ink: #e9fff2;
  --shadow: 0 18px 45px rgba(0, 0, 0, 0.32);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
  transition: background-color 160ms ease, color 160ms ease;
}

a {
  color: inherit;
}

[hidden] {
  display: none !important;
}

.skip-link {
  position: absolute;
  left: 16px;
  top: 12px;
  z-index: 10;
  transform: translateY(-140%);
  border-radius: 6px;
  background: var(--brand-dark);
  color: var(--paper);
  padding: 8px 12px;
  text-decoration: none;
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header,
.site-footer {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 20px 0;
}

.brand {
  color: var(--brand-dark);
  font-weight: 800;
  text-decoration: none;
}

nav {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
}

nav a {
  color: var(--muted);
  font-size: 0.95rem;
  text-decoration: none;
}

nav a:hover {
  color: var(--brand-dark);
}

.text-link {
  color: var(--brand-dark);
  font-weight: 800;
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

.breadcrumbs {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 18px 0 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.breadcrumbs a {
  text-decoration: none;
}

.breadcrumbs a:hover {
  color: var(--brand-dark);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 22px;
}

.theme-switcher {
  display: grid;
  grid-template-columns: repeat(2, minmax(64px, 1fr));
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
}

.theme-switcher button {
  border: 0;
  border-right: 1px solid var(--line);
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font: inherit;
  font-size: 0.88rem;
  font-weight: 800;
  padding: 8px 10px;
}

.theme-switcher button:last-child {
  border-right: 0;
}

.theme-switcher button[aria-pressed="true"] {
  background: var(--brand);
  color: var(--paper);
}

.hero,
.page-header,
.section {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 440px);
  gap: 42px;
  align-items: center;
  padding: 72px 0 48px;
}

.page-header {
  padding: 64px 0 24px;
}

.eyebrow {
  color: var(--brand);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2 {
  margin: 0 0 14px;
  line-height: 1.08;
}

h1 {
  max-width: 780px;
  font-size: 4.5rem;
}

h2 {
  font-size: 1.75rem;
}

h3 {
  margin: 0 0 10px;
  line-height: 1.2;
}

p {
  margin-top: 0;
}

.lede,
.page-header p,
.section-heading p {
  max-width: 680px;
  color: var(--muted);
  font-size: 1.08rem;
}

.calculator,
.note-panel,
.card {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.calculator {
  padding: 22px;
}

.field-grid {
  display: grid;
  gap: 14px;
}

label span {
  display: block;
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 700;
}

input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 12px;
  background: var(--paper);
  color: var(--ink);
  font: inherit;
}

.preset-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 16px;
}

.preset-row button {
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
  color: var(--muted);
  cursor: pointer;
  font: inherit;
  font-size: 0.86rem;
  font-weight: 800;
  padding: 8px 10px;
}

.preset-row button:hover,
.preset-row button[aria-pressed="true"] {
  border-color: var(--brand);
  background: var(--panel-soft);
  color: var(--brand-dark);
}

.usage-summary {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  margin-top: 16px;
  padding: 14px;
}

.usage-summary span {
  display: block;
  color: var(--muted);
  font-size: 0.84rem;
}

.usage-summary strong {
  display: block;
  margin-top: 4px;
  color: var(--ink);
  font-size: 1.2rem;
}

.results {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-top: 18px;
}

.results div {
  border-radius: 8px;
  background: var(--panel-soft);
  padding: 14px;
}

.results span,
.card span,
.card small {
  display: block;
  color: var(--muted);
  font-size: 0.84rem;
}

.results strong {
  display: block;
  margin-top: 4px;
  color: var(--brand-dark);
  font-size: 1.25rem;
}

.section {
  padding: 42px 0;
}

.compact-section {
  padding-bottom: 0;
}

.section-heading {
  margin-bottom: 20px;
}

.filter-panel {
  display: grid;
  gap: 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
  max-width: 620px;
  padding: 18px;
}

.filter-panel p,
.empty-state {
  margin: 0;
  color: var(--muted);
}

.category-list {
  display: grid;
  gap: 42px;
}

.category-section {
  display: grid;
  gap: 6px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.card {
  display: grid;
  gap: 10px;
  min-height: 150px;
  padding: 18px;
  text-decoration: none;
}

.card:hover {
  border-color: var(--brand);
  transform: translateY(-1px);
}

.card strong {
  font-size: 1.08rem;
  line-height: 1.25;
}

.category-card {
  min-height: 170px;
}

.formula-band {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.two-column {
  display: grid;
  grid-template-columns: minmax(320px, 440px) minmax(0, 1fr);
  gap: 28px;
  align-items: start;
}

.note-panel {
  padding: 24px;
}

.insight-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.insight-panel {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
  padding: 20px;
}

.insight-panel p {
  margin: 0;
  color: var(--muted);
}

.editorial-note {
  display: grid;
  gap: 4px;
  border-left: 4px solid var(--accent);
  border-radius: 8px;
  background: var(--panel-soft);
  color: var(--muted);
  padding: 14px 18px;
}

.editorial-note strong {
  color: var(--ink);
}

.link-panel-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.link-panel {
  display: grid;
  gap: 8px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
  min-height: 136px;
  padding: 16px;
  text-decoration: none;
}

.link-panel:hover {
  border-color: var(--brand);
  transform: translateY(-1px);
}

.link-panel span,
.link-panel small {
  display: block;
  color: var(--muted);
  font-size: 0.84rem;
}

.link-panel strong {
  color: var(--ink);
  line-height: 1.25;
}

.checklist-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.checklist-panel {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
  padding: 22px;
}

.checklist-panel span {
  display: block;
  color: var(--brand);
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
}

.checklist-panel h2 {
  margin-top: 8px;
}

.checklist-panel ul {
  margin: 0;
  padding-left: 20px;
  color: var(--muted);
}

.checklist-panel li + li {
  margin-top: 8px;
}

pre {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--code-bg);
  color: var(--code-ink);
  padding: 18px;
}

.article-block p {
  color: var(--muted);
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
}

table {
  width: 100%;
  border-collapse: collapse;
  min-width: 680px;
}

th,
td {
  border-bottom: 1px solid var(--line);
  padding: 14px 16px;
  text-align: left;
}

th {
  background: var(--panel-soft);
  color: var(--brand-dark);
  font-size: 0.86rem;
}

tbody tr:last-child td {
  border-bottom: 0;
}

.faq-list {
  display: grid;
  gap: 12px;
}

details {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  padding: 16px 18px;
}

summary {
  cursor: pointer;
  color: var(--ink);
  font-weight: 800;
}

details p {
  margin: 12px 0 0;
  color: var(--muted);
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border-top: 1px solid var(--line);
  margin-top: 56px;
  padding: 26px 0;
  color: var(--muted);
  font-size: 0.92rem;
}

@media (max-width: 820px) {
  .site-header,
  .site-footer,
  .hero,
  .breadcrumbs,
  .page-header,
  .section {
    width: min(100% - 24px, 1120px);
  }

  .site-header,
  .site-footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .header-actions {
    align-items: flex-start;
    flex-direction: column;
    gap: 14px;
    width: 100%;
  }

  .theme-switcher {
    width: min(100%, 220px);
  }

  .hero,
  .two-column {
    grid-template-columns: 1fr;
    padding-top: 36px;
  }

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

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

  .link-panel-grid {
    grid-template-columns: 1fr;
  }

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

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

  h1 {
    font-size: 2.6rem;
  }
}