:root {
  --bg: #f4efe7;
  --bg-accent: #efe5d6;
  --surface: rgba(255, 255, 255, 0.88);
  --surface-strong: #ffffff;
  --text: #1f2933;
  --muted: #5f6c78;
  --line: rgba(31, 41, 51, 0.1);
  --line-strong: rgba(31, 41, 51, 0.16);
  --brand: #1f6f5f;
  --brand-dark: #174f45;
  --accent: #d28b4a;
  --warning: #8b3f2b;
  --shadow: 0 18px 50px rgba(47, 58, 76, 0.12);
  --radius-lg: 28px;
  --radius-md: 20px;
  --radius-sm: 14px;
  --container: 1180px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Source Sans 3", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(210, 139, 74, 0.15), transparent 32%),
    radial-gradient(circle at top right, rgba(31, 111, 95, 0.14), transparent 28%),
    linear-gradient(180deg, #f7f1e7 0%, #f4efe7 45%, #efe7db 100%);
  min-height: 100vh;
}

img,
iframe {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

button,
input,
textarea,
select {
  font: inherit;
}

.site-shell {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  width: min(calc(100% - 2rem), var(--container));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(18px);
  background: rgba(244, 239, 231, 0.82);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 84px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.85rem;
  font-family: "Manrope", sans-serif;
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  font-size: 1rem;
  font-weight: 800;
}

.brand small {
  color: var(--muted);
  font-size: 0.86rem;
  margin-top: 0.1rem;
}

.brand-mark {
  width: 48px;
  height: 48px;
  display: inline-grid;
  place-items: center;
  border-radius: 16px;
  background: linear-gradient(145deg, var(--brand), var(--brand-dark));
  color: #fff;
  font-weight: 800;
  letter-spacing: 0.04em;
  box-shadow: var(--shadow);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.site-nav a {
  padding: 0.8rem 1rem;
  border-radius: 999px;
  color: var(--muted);
  font-weight: 600;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.site-nav a:hover,
.site-nav a:focus-visible,
.site-nav a.is-active {
  background: rgba(31, 111, 95, 0.1);
  color: var(--brand-dark);
}

.nav-toggle {
  display: none;
  width: 48px;
  height: 48px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.65);
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 0.28rem;
  cursor: pointer;
}

.nav-toggle span {
  width: 20px;
  height: 2px;
  border-radius: 999px;
  background: var(--text);
}

main {
  flex: 1;
}

.hero,
.lesson-main {
  padding: 3.5rem 0 4rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(280px, 0.9fr);
  gap: 1.5rem;
  align-items: stretch;
}

.hero-copy,
.hero-panel,
.content-card,
.video-card,
.lesson-card {
  background: var(--surface);
  border: 1px solid rgba(255, 255, 255, 0.55);
  box-shadow: var(--shadow);
}

.hero-copy {
  padding: clamp(2rem, 4vw, 4rem);
  border-radius: var(--radius-lg);
}

.hero-copy h1,
.section-heading h2,
.lesson-hero h1,
.hero-panel h2 {
  font-family: "Manrope", sans-serif;
  line-height: 1.05;
  margin: 0;
}

.hero-copy h1 {
  font-size: clamp(2.4rem, 5vw, 4.75rem);
  max-width: 12ch;
}

.hero-panel {
  padding: 2rem;
  border-radius: var(--radius-lg);
}

.eyebrow {
  margin: 0 0 0.85rem;
  color: var(--brand);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.8rem;
  font-weight: 700;
}

.lead {
  margin: 1.2rem 0 0;
  font-size: 1.15rem;
  line-height: 1.7;
  color: var(--muted);
  max-width: 58ch;
}

.hero-actions,
.lesson-pagination {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
}

.hero-actions {
  margin-top: 2rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0.8rem 1.25rem;
  border-radius: 999px;
  font-weight: 700;
  transition: transform 0.2s ease, background-color 0.2s ease, color 0.2s ease;
}

.button:hover,
.button:focus-visible {
  transform: translateY(-1px);
}

.button-primary {
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
  color: #fff;
}

.button-secondary {
  background: rgba(31, 111, 95, 0.1);
  color: var(--brand-dark);
}

.button-ghost {
  background: rgba(31, 41, 51, 0.06);
  color: var(--muted);
}

.button.is-disabled {
  opacity: 0.65;
  pointer-events: none;
}

.check-list,
.bullet-list,
.ordered-list {
  margin: 0;
  padding-left: 1.15rem;
}

.check-list li,
.bullet-list li,
.ordered-list li {
  line-height: 1.65;
  margin-bottom: 0.65rem;
}

.info-card {
  margin-top: 2rem;
  padding: 1rem 1.1rem;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.75);
  border: 1px solid var(--line);
}

.section {
  padding: 1.5rem 0 4rem;
}

.section-muted {
  padding-top: 0;
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.section-heading p:last-child {
  max-width: 42ch;
  color: var(--muted);
  margin: 0;
}

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

.lesson-card {
  padding: 1.4rem;
  border-radius: var(--radius-md);
  min-height: 220px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.lesson-card:hover,
.lesson-card:focus-visible {
  transform: translateY(-4px);
  border-color: rgba(31, 111, 95, 0.25);
}

.lesson-number {
  display: inline-flex;
  width: 52px;
  height: 52px;
  align-items: center;
  justify-content: center;
  border-radius: 16px;
  background: rgba(210, 139, 74, 0.16);
  color: var(--accent);
  font-family: "Manrope", sans-serif;
  font-weight: 800;
}

.lesson-card h3,
.content-card h2 {
  margin: 1.25rem 0 0.6rem;
  font-family: "Manrope", sans-serif;
}

.lesson-card p,
.content-card p,
.quick-start p,
.footer-inner p,
.back-link,
.lesson-meta span {
  color: var(--muted);
}

.quick-start {
  background: rgba(255, 255, 255, 0.5);
  border: 1px solid rgba(255, 255, 255, 0.55);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 1.75rem;
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: 1.5rem;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  margin-bottom: 1rem;
  font-weight: 700;
}

.lesson-hero {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.4rem;
}

.lesson-hero h1 {
  font-size: clamp(2rem, 4vw, 3.4rem);
}

.lesson-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.65rem;
}

.lesson-meta span {
  background: rgba(255, 255, 255, 0.65);
  border: 1px solid var(--line);
  padding: 0.7rem 0.95rem;
  border-radius: 999px;
  font-weight: 700;
}

.video-card {
  border-radius: var(--radius-lg);
  padding: 1rem;
  margin-bottom: 1.4rem;
}

.video-frame {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  overflow: hidden;
  border-radius: calc(var(--radius-lg) - 8px);
  background:
    linear-gradient(135deg, rgba(31, 111, 95, 0.14), rgba(210, 139, 74, 0.18)),
    #ddd5c8;
}

.video-frame iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.lesson-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(280px, 0.8fr);
  gap: 1.25rem;
}

.content-card {
  border-radius: var(--radius-md);
  padding: 1.5rem;
}

.sidebar-stack {
  display: grid;
  gap: 1.25rem;
  align-content: start;
}

.warning-card {
  background: rgba(255, 248, 244, 0.92);
}

.lesson-pagination {
  justify-content: space-between;
  margin-top: 1.5rem;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.4);
}

.footer-inner {
  min-height: 78px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

@media (max-width: 1080px) {
  .lesson-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .hero-grid,
  .lesson-layout,
  .quick-start {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 760px) {
  .header-inner {
    flex-wrap: wrap;
    min-height: auto;
    padding: 1rem 0;
  }

  .nav-toggle {
    display: inline-flex;
    margin-left: auto;
  }

  .site-nav {
    width: 100%;
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding-top: 0.35rem;
  }

  .site-nav.is-open {
    display: flex;
  }

  .site-nav a {
    border-radius: 16px;
  }

  .hero,
  .lesson-main {
    padding: 2rem 0 3rem;
  }

  .hero-copy,
  .hero-panel,
  .video-card,
  .content-card,
  .lesson-card {
    border-radius: 22px;
  }

  .section-heading,
  .lesson-hero,
  .footer-inner,
  .lesson-pagination {
    flex-direction: column;
    align-items: flex-start;
  }

  .lesson-meta {
    justify-content: flex-start;
  }

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

  .button,
  .lesson-pagination .button {
    width: 100%;
  }
}