:root {
  color-scheme: light;
  --ink: #17211b;
  --muted: #5e6c63;
  --paper: #f6f4ed;
  --surface: #fffdf7;
  --line: #dcd8ca;
  --accent: #176b4d;
  --accent-soft: #dcecdf;
  --code: #202a24;
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  background:
    radial-gradient(circle at 85% 0%, rgba(188, 219, 195, 0.58), transparent 30rem),
    var(--paper);
  color: var(--ink);
  margin: 0;
  min-height: 100vh;
}

a {
  color: var(--accent);
}

.site-header {
  align-items: center;
  border-bottom: 1px solid rgba(23, 33, 27, 0.12);
  display: flex;
  justify-content: space-between;
  padding: 1rem clamp(1.25rem, 4vw, 4rem);
}

.brand {
  color: var(--ink);
  font-size: 1.08rem;
  font-weight: 760;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.quiet-link {
  color: var(--muted);
  font-size: 0.92rem;
  text-decoration: none;
}

.home-shell,
.article-shell {
  margin: 0 auto;
  max-width: 1080px;
  padding: clamp(3rem, 8vw, 7rem) clamp(1.25rem, 4vw, 4rem);
}

.hero {
  max-width: 780px;
}

.eyebrow,
.card-index {
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 760;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

h1 {
  font-size: clamp(2.4rem, 7vw, 5.3rem);
  letter-spacing: -0.055em;
  line-height: 0.98;
  margin: 0.5rem 0 1.5rem;
}

.hero-copy {
  color: var(--muted);
  font-size: clamp(1.05rem, 2vw, 1.3rem);
  line-height: 1.7;
}

.course-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  margin-top: clamp(3rem, 8vw, 6rem);
}

.course-card {
  background: rgba(255, 253, 247, 0.86);
  border: 1px solid var(--line);
  border-radius: 18px;
  color: var(--ink);
  min-height: 250px;
  padding: 1.6rem;
  text-decoration: none;
  transition: border-color 160ms ease, transform 160ms ease;
}

.course-card:hover {
  border-color: var(--accent);
  transform: translateY(-3px);
}

.course-card h2 {
  font-size: 1.55rem;
  letter-spacing: -0.025em;
  margin: 3rem 0 0.75rem;
}

.course-card p {
  color: var(--muted);
  line-height: 1.65;
}

.card-action {
  color: var(--accent);
  display: inline-block;
  font-weight: 700;
  margin-top: 1.25rem;
}

.card-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0 1.25rem;
}

.article-shell {
  max-width: 900px;
  padding-top: 3rem;
}

.article {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: 0 18px 60px rgba(43, 56, 47, 0.08);
  padding: clamp(1.4rem, 5vw, 4rem);
}

.article h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  line-height: 1.08;
}

.article h2 {
  border-top: 1px solid var(--line);
  font-size: 1.55rem;
  margin-top: 3rem;
  padding-top: 1.5rem;
}

.article h3 {
  font-size: 1.2rem;
  margin-top: 2rem;
}

.article p,
.article li {
  line-height: 1.75;
}

.article blockquote {
  background: var(--accent-soft);
  border-left: 4px solid var(--accent);
  margin: 1.5rem 0;
  padding: 0.7rem 1.2rem;
}

.article pre {
  background: var(--code);
  border-radius: 10px;
  color: #eef5ef;
  overflow-x: auto;
  padding: 1rem;
}

.article code {
  font-family: "SFMono-Regular", Consolas, monospace;
  font-size: 0.9em;
}

.article :not(pre) > code {
  background: #e9e8e0;
  border-radius: 4px;
  padding: 0.12rem 0.35rem;
}

.article table {
  border-collapse: collapse;
  display: block;
  overflow-x: auto;
  width: 100%;
}

.article th,
.article td {
  border: 1px solid var(--line);
  padding: 0.65rem;
  text-align: left;
}

.article img {
  height: auto;
  max-width: 100%;
}

@media (max-width: 640px) {
  .site-header {
    padding-inline: 1.25rem;
  }

  .article-shell {
    padding-inline: 0.75rem;
  }

  .article {
    border-radius: 12px;
  }
}