:root {
  --page-bg: #f4f9f8;
  --page-surface: #ffffff;
  --page-surface-alt: #edf9f7;
  --page-ink: #17333b;
  --page-muted: #557077;
  --page-line: #dfeae7;
  --page-teal: #096b72;
  --page-teal-bright: #15a3a3;
  --page-dark: #0d3b49;
  --page-shadow: 0 18px 40px rgba(13, 59, 73, .10);
}

body.demo-page {
  background: linear-gradient(180deg, #eef8f7 0%, #f7fbfa 24%, #ffffff 100%);
  color: var(--page-ink);
}

.demo-shell {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.25rem 4rem;
}

.demo-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.1rem 0 1.5rem;
  border-bottom: 1px solid var(--page-line);
}

.demo-header .brand {
  font-size: 1rem;
}

.demo-header nav {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem 1.25rem;
  align-items: center;
}

.demo-header nav a {
  color: var(--page-muted);
  text-decoration: none;
  font-weight: 700;
}

.demo-hero {
  position: relative;
  padding: 4rem 0 2rem;
  margin-bottom: 2rem;
}

.demo-hero::before {
  content: "";
  position: absolute;
  left: 0;
  top: 2rem;
  width: 0.45rem;
  height: calc(100% - 2.5rem);
  background: linear-gradient(180deg, var(--page-teal-bright), var(--page-teal));
  border-radius: 999px;
}

.demo-hero-inner {
  background: var(--page-surface);
  border: 1px solid var(--page-line);
  border-left: 0;
  box-shadow: var(--page-shadow);
  border-radius: 0 1.5rem 1.5rem 0;
  padding: 2.75rem clamp(1.5rem, 3vw, 3rem);
}

.demo-kicker {
  color: var(--page-teal);
  text-transform: uppercase;
  letter-spacing: .14em;
  font-size: .78rem;
  font-weight: 900;
}

.demo-hero h1 {
  margin: 1rem 0 1rem;
  font-size: clamp(2.5rem, 6vw, 5rem);
  letter-spacing: -.07em;
  line-height: .95;
  color: var(--page-dark);
}

.demo-hero p {
  max-width: 760px;
  font-size: 1.1rem;
  color: var(--page-muted);
}

.demo-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
  margin-top: 2rem;
}

.demo-page-grid {
  display: grid;
  gap: 2rem;
  grid-template-columns: minmax(0, 1.6fr) minmax(260px, 0.8fr);
  align-items: start;
}

.article-panel,
.sidebar-panel,
.callout-panel {
  background: var(--page-surface);
  border: 1px solid var(--page-line);
  border-radius: 1.15rem;
  box-shadow: var(--page-shadow);
}

.article-panel {
  padding: clamp(1.5rem, 3vw, 2.5rem);
}

.sidebar-panel {
  padding: 1.4rem 1.25rem;
  position: sticky;
  top: 4.5rem;
}

.sidebar-panel h3,
.callout-panel h3 {
  margin: 0 0 1rem;
  color: var(--page-dark);
  letter-spacing: -.04em;
}

.toc {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: .7rem;
}

.toc a {
  color: var(--page-teal);
  text-decoration: none;
  font-weight: 700;
}

.article-panel section {
  padding-top: 1.2rem;
  margin-top: 1.2rem;
  border-top: 1px solid var(--page-line);
}

.article-panel section:first-of-type {
  padding-top: 0;
  margin-top: 0;
  border-top: 0;
}

.article-panel h2 {
  color: var(--page-dark);
  font-size: clamp(1.75rem, 3vw, 2.8rem);
  letter-spacing: -.05em;
  margin: 0 0 1rem;
}

.article-panel h3 {
  color: var(--page-teal);
  margin: 1.3rem 0 .6rem;
  font-size: 1.15rem;
}

.article-panel p,
.article-panel li,
.article-panel dd,
.article-panel dt,
.article-panel blockquote {
  color: var(--page-muted);
  line-height: 1.7;
  font-size: 1.02rem;
}

.article-panel ul,
.article-panel ol {
  margin: 1rem 0 1rem 1.5rem;
  padding: 0;
}

.article-panel li + li {
  margin-top: .35rem;
}

.article-panel blockquote {
  background: var(--page-surface-alt);
  border-left: .35rem solid var(--page-teal-bright);
  border-radius: 0 .65rem .65rem 0;
  padding: 1rem 1.15rem;
  margin: 1.5rem 0;
}

.teaching-point {
  background: var(--page-dark);
  border-radius: .75rem;
  color: #dff7f3 !important;
  margin-top: 1.5rem;
  padding: 1rem 1.15rem;
}

.teaching-point strong {
  color: #9ee6dd;
  display: block;
  font-size: .75rem;
  letter-spacing: .1em;
  margin-bottom: .25rem;
  text-transform: uppercase;
}

.review-guide {
  display: grid;
  gap: 1rem;
  margin: 1.5rem 0;
}

.artifact-review {
  background: linear-gradient(180deg, var(--page-surface-alt), #fff);
  border: 1px solid var(--page-line);
  border-left: .3rem solid var(--page-teal-bright);
  border-radius: .9rem;
  padding: 1.1rem 1.2rem;
}

.artifact-review h3 {
  margin-top: 0;
}

.artifact-review dl {
  margin: 0;
}

.artifact-review dt {
  color: var(--page-dark);
  font-weight: 850;
  margin-top: .75rem;
}

.artifact-review dt:first-child {
  margin-top: 0;
}

.artifact-review dd {
  margin: .15rem 0 0;
}

.callout-panel {
  margin-top: 1.8rem;
  padding: 1.35rem 1.25rem;
  background: linear-gradient(180deg, var(--page-surface-alt), #fff);
}

.metric-grid,
.card-grid,
.two-col {
  display: grid;
  gap: 1rem;
}

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

.metric-grid .stat {
  background: var(--page-surface-alt);
  border: 1px solid var(--page-line);
  border-radius: .9rem;
  padding: 1rem 1.1rem;
}

.metric-grid .stat strong {
  display: block;
  color: var(--page-dark);
  font-size: 1.1rem;
  margin-bottom: .25rem;
}

.metric-grid .stat .text-link {
  display: block;
  margin-top: .65rem;
}

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

.card-grid article,
.two-col > div {
  background: var(--page-surface-alt);
  border: 1px solid var(--page-line);
  border-radius: .9rem;
  padding: 1rem 1.1rem;
}

.card-grid h4,
.two-col h4 {
  margin: 0 0 .5rem;
  color: var(--page-dark);
}

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

.badge {
  display: inline-block;
  background: rgba(21, 163, 163, .1);
  color: var(--page-teal);
  border-radius: 999px;
  padding: .35rem .7rem;
  font-size: .72rem;
  font-weight: 900;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.source-link {
  color: var(--page-teal);
  font-weight: 800;
  text-decoration: none;
}

.inline-code {
  font-family: "SFMono-Regular", ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  background: rgba(9, 107, 114, .06);
  border-radius: .35rem;
  padding: .12rem .35rem;
}

@media (max-width: 900px) {
  .demo-page-grid {
    grid-template-columns: 1fr;
  }

  .sidebar-panel {
    position: static;
  }

  .metric-grid,
  .card-grid,
  .two-col {
    grid-template-columns: 1fr;
  }
}

@media (print) {
  .demo-header, .demo-hero-actions, .sidebar-panel {
    display: none !important;
  }

  .demo-shell {
    max-width: none;
    padding: 0;
  }

  .demo-hero {
    padding-top: 1rem;
  }

  .demo-hero-inner,
  .article-panel,
  .callout-panel,
  .sidebar-panel {
    box-shadow: none;
  }

  .article-panel {
    border: 0;
    padding: 0;
  }

  .article-panel section {
    break-inside: avoid;
  }

  .artifact-review {
    break-inside: avoid;
  }

  .teaching-point {
    background: #edf9f7;
    border-left: .2rem solid var(--page-teal);
    color: var(--page-ink) !important;
  }

  .teaching-point strong {
    color: var(--page-teal);
  }
}