/* ==========================================================================
   Section 3: Google Fonts Import
   Load Playfair Display (400, 600, 700) and Inter (400, 500, 600) with swap.
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&family=Playfair+Display:wght@400;600;700&display=swap');

/* ==========================================================================
   Section 1: CSS Custom Properties -- Root (Light Mode Default)
   All tokens sourced from DESIGN.md Sections 2, 3, 5, and 6.
   ========================================================================== */

:root {
  /* -- Color tokens (Light Mode) -- */
  --color-primary: #B45309;
  --color-primary-hover: #92400E;
  --color-primary-light: #FEF3C7;
  --color-primary-subtle: #FFFBEB;
  --color-accent: #D97706;
  --color-background: #FFFCF7;
  --color-surface: #FFFFFF;
  --color-surface-alt: #F5F1EB;
  --color-text-primary: #1C1917;
  --color-text-secondary: #57534E;
  --color-text-muted: #A8A29E;
  --color-border: #E7E0D6;
  --color-border-strong: #D6CEC2;
  --color-error: #DC2626;
  --color-error-bg: #FEF2F2;
  --color-warning: #D97706;
  --color-warning-bg: #FFFBEB;
  --color-success: #16A34A;
  --color-success-bg: #F0FDF4;
  --color-shipped-bg: #DBEAFE;
  --color-shipped-text: #1D4ED8;

  /* -- Typography tokens -- */
  --font-heading: 'Playfair Display', Georgia, 'Times New Roman', serif;
  --font-body: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', Consolas, monospace;

  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* -- Type scale tokens (h1–h6, body variants, caption, overline, code) -- */
  --text-h1-size: 3rem;
  --text-h1-weight: 700;
  --text-h1-line-height: 1.15;
  --text-h1-letter-spacing: -0.02em;

  --text-h2-size: 2.25rem;
  --text-h2-weight: 600;
  --text-h2-line-height: 1.2;
  --text-h2-letter-spacing: -0.015em;

  --text-h3-size: 1.75rem;
  --text-h3-weight: 600;
  --text-h3-line-height: 1.3;
  --text-h3-letter-spacing: -0.01em;

  --text-h4-size: 1.375rem;
  --text-h4-weight: 600;
  --text-h4-line-height: 1.35;
  --text-h4-letter-spacing: -0.005em;

  --text-h5-size: 1.125rem;
  --text-h5-weight: 500;
  --text-h5-line-height: 1.4;
  --text-h5-letter-spacing: 0;

  --text-h6-size: 1rem;
  --text-h6-weight: 500;
  --text-h6-line-height: 1.4;
  --text-h6-letter-spacing: 0;

  --text-body-lg-size: 1.125rem;
  --text-body-lg-weight: 400;
  --text-body-lg-line-height: 1.65;
  --text-body-lg-letter-spacing: 0;

  --text-body-size: 1rem;
  --text-body-weight: 400;
  --text-body-line-height: 1.6;
  --text-body-letter-spacing: 0;

  --text-body-sm-size: 0.875rem;
  --text-body-sm-weight: 400;
  --text-body-sm-line-height: 1.5;
  --text-body-sm-letter-spacing: 0.005em;

  --text-caption-size: 0.75rem;
  --text-caption-weight: 400;
  --text-caption-line-height: 1.5;
  --text-caption-letter-spacing: 0.01em;

  --text-overline-size: 0.75rem;
  --text-overline-weight: 600;
  --text-overline-line-height: 1.5;
  --text-overline-letter-spacing: 0.1em;

  --text-code-size: 0.875em;
  --text-code-weight: 400;
  --text-code-line-height: 1.6;
  --text-code-letter-spacing: 0;

  /* -- Spacing scale tokens -- */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;
  --space-9: 80px;

  /* -- Shadow scale tokens (warm-toned rgba) -- */
  --shadow-xs: 0 1px 2px rgba(28, 25, 23, 0.04);
  --shadow-sm: 0 1px 3px rgba(28, 25, 23, 0.06), 0 1px 2px rgba(28, 25, 23, 0.04);
  --shadow-md: 0 4px 8px rgba(28, 25, 23, 0.08), 0 2px 4px rgba(28, 25, 23, 0.04);
  --shadow-lg: 0 8px 24px rgba(28, 25, 23, 0.1), 0 4px 8px rgba(28, 25, 23, 0.04);
  --shadow-xl: 0 16px 48px rgba(28, 25, 23, 0.12), 0 8px 16px rgba(28, 25, 23, 0.04);

  /* -- Layout tokens -- */
  --container-narrow: 640px;
  --container-standard: 960px;
  --container-wide: 1200px;
  --gutter: 24px;
  --margin-mobile: 16px;
  --margin-tablet: 24px;
  --margin-desktop: 32px;
  --nav-height: 72px;

  /* -- Border radius tokens -- */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-full: 9999px;

  /* -- Transition tokens -- */
  --transition-fast: 200ms ease-out;
  --transition-base: 250ms ease-out;
  --transition-slow: 300ms ease-out;
}

/* ==========================================================================
   Section 2: CSS Custom Properties -- Dark Mode
   Overrides color tokens and reduces shadow opacity by ~20%.
   ========================================================================== */

[data-theme="dark"] {
  --color-primary: #F59E0B;
  --color-primary-hover: #FBBF24;
  --color-primary-light: #451A03;
  --color-primary-subtle: #1C1207;
  --color-accent: #FBBF24;
  --color-background: #1C1917;
  --color-surface: #292524;
  --color-surface-alt: #1C1917;
  --color-text-primary: #FAFAF9;
  --color-text-secondary: #D6D3D1;
  --color-text-muted: #78716C;
  --color-border: #44403C;
  --color-border-strong: #57534E;
  --color-error: #FCA5A5;
  --color-error-bg: #1C1917;
  --color-warning: #FBBF24;
  --color-warning-bg: #1C1917;
  --color-success: #4ADE80;
  --color-success-bg: #1C1917;
  --color-shipped-bg: #1E3A5F;
  --color-shipped-text: #93C5FD;

  --shadow-xs: 0 1px 2px rgba(28, 25, 23, 0.03);
  --shadow-sm: 0 1px 3px rgba(28, 25, 23, 0.05), 0 1px 2px rgba(28, 25, 23, 0.03);
  --shadow-md: 0 4px 8px rgba(28, 25, 23, 0.06), 0 2px 4px rgba(28, 25, 23, 0.03);
  --shadow-lg: 0 8px 24px rgba(28, 25, 23, 0.08), 0 4px 8px rgba(28, 25, 23, 0.03);
  --shadow-xl: 0 16px 48px rgba(28, 25, 23, 0.1), 0 8px 16px rgba(28, 25, 23, 0.03);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-primary: #F59E0B;
    --color-primary-hover: #FBBF24;
    --color-primary-light: #451A03;
    --color-primary-subtle: #1C1207;
    --color-accent: #FBBF24;
    --color-background: #1C1917;
    --color-surface: #292524;
    --color-surface-alt: #1C1917;
    --color-text-primary: #FAFAF9;
    --color-text-secondary: #D6D3D1;
    --color-text-muted: #78716C;
    --color-border: #44403C;
    --color-border-strong: #57534E;
    --color-error: #FCA5A5;
    --color-error-bg: #1C1917;
    --color-warning: #FBBF24;
    --color-warning-bg: #1C1917;
    --color-success: #4ADE80;
    --color-success-bg: #1C1917;
    --color-shipped-bg: #1E3A5F;
    --color-shipped-text: #93C5FD;

    --shadow-xs: 0 1px 2px rgba(28, 25, 23, 0.03);
    --shadow-sm: 0 1px 3px rgba(28, 25, 23, 0.05), 0 1px 2px rgba(28, 25, 23, 0.03);
    --shadow-md: 0 4px 8px rgba(28, 25, 23, 0.06), 0 2px 4px rgba(28, 25, 23, 0.03);
    --shadow-lg: 0 8px 24px rgba(28, 25, 23, 0.08), 0 4px 8px rgba(28, 25, 23, 0.03);
    --shadow-xl: 0 16px 48px rgba(28, 25, 23, 0.1), 0 8px 16px rgba(28, 25, 23, 0.03);
  }
}

/* ==========================================================================
   Section 4: CSS Reset and Base Styles
   ========================================================================== */

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

body,
h1,
h2,
h3,
h4,
h5,
h6,
p,
ul,
ol,
figure {
  margin: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-body-size);
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-background);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  -webkit-tap-highlight-color: transparent;
}

::selection {
  background: var(--color-primary-light);
  color: var(--color-text-primary);
}

/* ==========================================================================
   Section 5: Base Typography Elements
   ========================================================================== */

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-heading);
  color: var(--color-text-primary);
}

h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: var(--text-h1-weight);
  line-height: var(--text-h1-line-height);
  letter-spacing: var(--text-h1-letter-spacing);
}

h2 {
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: var(--text-h2-weight);
  line-height: var(--text-h2-line-height);
  letter-spacing: var(--text-h2-letter-spacing);
}

h3 {
  font-size: clamp(1.375rem, 3vw, 1.75rem);
  font-weight: var(--text-h3-weight);
  line-height: var(--text-h3-line-height);
  letter-spacing: var(--text-h3-letter-spacing);
}

h4 {
  font-size: var(--text-h4-size);
  font-weight: var(--text-h4-weight);
  line-height: var(--text-h4-line-height);
  letter-spacing: var(--text-h4-letter-spacing);
}

h5 {
  font-size: var(--text-h5-size);
  font-weight: var(--text-h5-weight);
  line-height: var(--text-h5-line-height);
  letter-spacing: var(--text-h5-letter-spacing);
}

h6 {
  font-size: var(--text-h6-size);
  font-weight: var(--text-h6-weight);
  line-height: var(--text-h6-line-height);
  letter-spacing: var(--text-h6-letter-spacing);
}

a {
  color: var(--color-primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* ==========================================================================
   Section 6: Utility Classes
   ========================================================================== */

.container-narrow {
  max-width: var(--container-narrow);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--margin-mobile);
  padding-right: var(--margin-mobile);
}

.container-standard {
  max-width: var(--container-standard);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--margin-mobile);
  padding-right: var(--margin-mobile);
}

.container-wide {
  max-width: var(--container-wide);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--margin-mobile);
  padding-right: var(--margin-mobile);
}

@media (min-width: 768px) {
  .container-narrow,
  .container-standard,
  .container-wide {
    padding-left: var(--margin-tablet);
    padding-right: var(--margin-tablet);
  }
}

@media (min-width: 1024px) {
  .container-narrow,
  .container-standard,
  .container-wide {
    padding-left: var(--margin-desktop);
    padding-right: var(--margin-desktop);
  }
}

.section {
  max-width: var(--container-wide);
  margin-left: auto;
  margin-right: auto;
  padding: var(--space-9) var(--margin-mobile);
}

@media (min-width: 768px) {
  .section {
    padding-left: var(--margin-tablet);
    padding-right: var(--margin-tablet);
  }
}

@media (min-width: 1024px) {
  .section {
    padding-left: var(--margin-desktop);
    padding-right: var(--margin-desktop);
  }
}

.section--alt {
  background: var(--color-surface-alt);
}

.section--alt-bordered {
  background: var(--color-surface-alt);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

@media (max-width: 767px) {
  .section {
    padding-top: var(--space-7);
    padding-bottom: var(--space-7);
  }
}

.overline {
  font-family: var(--font-body);
  font-size: var(--text-overline-size);
  font-weight: var(--text-overline-weight);
  line-height: var(--text-overline-line-height);
  letter-spacing: var(--text-overline-letter-spacing);
  text-transform: uppercase;
  color: var(--color-primary);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ==========================================================================
   Section 7: Reduced Motion
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ==========================================================================
   Section 8: Component - Buttons
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-body);
  font-weight: var(--font-weight-semibold);
  font-size: 0.9375rem;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: background var(--transition-fast), transform 100ms ease-out;
}

.btn:active {
  transform: scale(0.98);
}

.btn:focus-visible {
  box-shadow: 0 0 0 2px var(--color-background), 0 0 0 4px var(--color-primary);
  outline: none;
}

.btn--primary {
  background: var(--color-primary);
  color: #FFFFFF;
  box-shadow: 0 1px 3px color-mix(in srgb, var(--color-primary) 25%, transparent);
}

.btn--primary:hover {
  background: var(--color-primary-hover);
  box-shadow: 0 2px 6px color-mix(in srgb, var(--color-primary) 30%, transparent);
}

.btn--secondary {
  background: var(--color-surface);
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
}

.btn--secondary:hover {
  border-color: var(--color-border-strong);
  background: var(--color-surface-alt);
}

.btn--ghost {
  background: transparent;
  color: var(--color-text-secondary);
  border: none;
}

.btn--ghost:hover {
  background: var(--color-surface-alt);
  color: var(--color-text-primary);
}

.btn--destructive {
  background: var(--color-error);
  color: #FFFFFF;
}

.btn--destructive:hover {
  opacity: 0.9;
}

.btn--sm {
  font-size: 0.8125rem;
  padding: 8px 16px;
}

.btn--lg {
  font-size: 1.0625rem;
  padding: 16px 36px;
}

@media (max-width: 767px) {
  .btn--lg {
    padding: 14px 28px;
    font-size: 1rem;
  }
}

/* ==========================================================================
   Section 9: Component - Cards
   ========================================================================== */

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base), transform var(--transition-base);
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

a.card:focus-visible,
.card:focus-visible {
  box-shadow: 0 0 0 2px var(--color-background), 0 0 0 4px var(--color-primary);
  outline: none;
}

.card--featured {
  background: var(--color-surface);
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-md);
  transition: box-shadow var(--transition-slow), transform var(--transition-slow);
}

.card--featured:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.card--chapter {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  box-shadow: var(--shadow-xs);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.card--chapter:hover {
  border-color: color-mix(in srgb, var(--color-primary) 40%, transparent);
  box-shadow: var(--shadow-sm);
  transform: translateY(-1px);
}

.card--chapter .chapter-description {
  flex: 1;
}

.card--chapter .body-sm {
  margin-top: var(--space-2);
}

/* ==========================================================================
   Section 10: Component - Blockquote and Testimonial
   ========================================================================== */

.blockquote {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-normal);
  font-style: italic;
  font-size: 1.25rem;
  color: var(--color-text-primary);
  border-left: 3px solid var(--color-primary);
  padding: 16px 24px;
  background: var(--color-primary-subtle);
  border-radius: 0 8px 8px 0;
}

.blockquote__text {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-normal);
  font-style: italic;
  font-size: 1.25rem;
  color: var(--color-text-primary);
}

.blockquote__attribution {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  text-align: right;
  margin-top: var(--space-3);
}

.testimonial-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-md);
  transition: box-shadow var(--transition-slow), transform var(--transition-slow);
  position: relative;
}

.testimonial-card::before {
  content: "\201C";
  font-family: var(--font-heading);
  font-size: 4rem;
  line-height: 1;
  color: var(--color-primary-light);
  position: absolute;
  top: 12px;
  left: 24px;
  pointer-events: none;
}

[data-theme="dark"] .testimonial-card::before {
  color: var(--color-primary-light);
}

.testimonial-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

/* ==========================================================================
   Section 11: Component - Hero Section
   ========================================================================== */

.hero {
  min-height: 80vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-8) var(--margin-mobile);
  background:
    radial-gradient(ellipse 60% 50% at 50% 0%, var(--color-primary-light), transparent),
    var(--color-background);
}

[data-theme="dark"] .hero {
  background:
    radial-gradient(ellipse 60% 50% at 50% 0%, var(--color-primary-light), transparent),
    var(--color-background);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .hero {
    background:
      radial-gradient(ellipse 60% 50% at 50% 0%, var(--color-primary-light), transparent),
      var(--color-background);
  }
}

@media (min-width: 768px) {
  .hero {
    padding: var(--space-8) var(--margin-tablet);
  }
}

@media (min-width: 1024px) {
  .hero {
    padding: 96px var(--margin-desktop);
  }
}

.hero__inner {
  max-width: var(--container-wide);
  width: 100%;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-7);
}

@media (min-width: 1024px) {
  .hero__inner {
    flex-direction: row;
    align-items: center;
    gap: var(--space-9);
  }
}

/* -- Book Cover -- */

.hero__cover {
  flex-shrink: 0;
  display: flex;
  justify-content: center;
}

@media (min-width: 1024px) {
  .hero__cover {
    flex: 0 0 auto;
    justify-content: flex-end;
  }
}

.hero__cover-image {
  display: block;
  width: 144px;
  height: auto;
  border-radius: var(--radius-md);
  object-fit: cover;
}

@media (min-width: 768px) {
  .hero__cover-image {
    width: 182px;
  }
}

@media (min-width: 1024px) {
  .hero__cover-image {
    width: 210px;
  }
}

@media (min-width: 1280px) {
  .hero__cover-image {
    width: 234px;
  }
}

/* -- Hero Text Content -- */

.hero__content {
  text-align: center;
}

@media (min-width: 1024px) {
  .hero__content {
    text-align: left;
    flex: 1;
    min-width: 0;
  }
}

.hero__overline {
  font-family: var(--font-body);
  font-size: var(--text-overline-size);
  font-weight: var(--text-overline-weight);
  line-height: var(--text-overline-line-height);
  letter-spacing: var(--text-overline-letter-spacing);
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.hero__title {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-bold);
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  line-height: 1.1;
  color: var(--color-text-primary);
  margin-bottom: var(--space-3);
}

.hero__accent {
  display: block;
  width: 48px;
  height: 3px;
  background: var(--color-primary);
  border-radius: var(--radius-full);
  margin: var(--space-4) auto var(--space-5);
}

@media (min-width: 1024px) {
  .hero__accent {
    margin-left: 0;
    margin-right: 0;
  }
}

.hero__subtitle {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-normal);
  font-style: italic;
  font-size: clamp(1.125rem, 2.5vw, 1.5rem);
  line-height: 1.4;
  color: var(--color-text-secondary);
  max-width: 540px;
  margin-bottom: var(--space-5);
}

@media (min-width: 1024px) {
  .hero__subtitle {
    margin-left: 0;
    margin-right: 0;
  }
}

.hero__description {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-lg-size);
  line-height: var(--text-body-lg-line-height);
  color: var(--color-text-secondary);
  max-width: 480px;
  margin-bottom: var(--space-6);
}

.hero__actions {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  align-items: center;
}

@media (min-width: 640px) {
  .hero__actions {
    flex-direction: row;
  }
}

@media (min-width: 1024px) {
  .hero__actions {
    justify-content: flex-start;
  }
}

/* ==========================================================================
   Section 12: Component - Section Layout
   ========================================================================== */

.section__overline {
  font-family: var(--font-body);
  font-size: var(--text-overline-size);
  font-weight: var(--text-overline-weight);
  line-height: var(--text-overline-line-height);
  letter-spacing: var(--text-overline-letter-spacing);
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.section__heading {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-semibold);
  font-size: 2rem;
  color: var(--color-text-primary);
  margin-bottom: var(--space-7);
}

@media (max-width: 767px) {
  .section__heading {
    margin-bottom: var(--space-6);
  }
}

/* ==========================================================================
   Section 13: Component - Grid Layouts
   ========================================================================== */

.grid {
  display: grid;
  gap: var(--gutter);
}

@media (max-width: 767px) {
  .grid {
    gap: var(--space-4);
  }
}

.grid--2col {
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  .grid--2col {
    grid-template-columns: 1fr 1fr;
  }
}

.grid--4col {
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  .grid--4col {
    grid-template-columns: 1fr 1fr;
  }
}

@media (min-width: 1280px) {
  .grid--4col {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* ==========================================================================
   Section 14: Component - Chapter Card Content
   ========================================================================== */

.chapter-overline {
  font-family: var(--font-body);
  font-weight: var(--font-weight-semibold);
  font-size: var(--text-overline-size);
  text-transform: uppercase;
  letter-spacing: var(--text-overline-letter-spacing);
  color: var(--color-primary);
}

.chapter-title {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-semibold);
  font-size: 1rem;
  color: var(--color-text-primary);
}

.chapter-description {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

/* ==========================================================================
   Section 15: Component - Badges
   ========================================================================== */

.badge {
  display: inline-flex;
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: var(--font-weight-medium);
}

.badge--primary {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

.badge--default {
  background: var(--color-surface-alt);
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
}

.badge--success {
  background: var(--color-success-bg);
  color: var(--color-success);
}

.badge--warning {
  background: var(--color-warning-bg);
  color: var(--color-warning);
}

.badge--error {
  background: var(--color-error-bg);
  color: var(--color-error);
}

/* ==========================================================================
   Section 16: Component - Price Display
   ========================================================================== */

.price {
  font-family: var(--font-body);
  font-weight: var(--font-weight-bold);
  font-size: 2rem;
  color: var(--color-text-primary);
}

.price__currency {
  font-family: var(--font-body);
  font-weight: var(--font-weight-medium);
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

.price__discount {
  text-decoration: line-through;
  color: var(--color-text-muted);
}

.price--free {
  color: var(--color-primary);
}

/* ==========================================================================
   Section 17: Component - Divider
   ========================================================================== */

.divider {
  height: 1px;
  background: var(--color-border);
  margin: var(--space-6) 0;
}

.divider--accent {
  display: flex;
  align-items: center;
  justify-content: center;
  height: auto;
  background: none;
  margin: var(--space-8) 0;
}

.divider--accent::before,
.divider--accent::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--color-border);
}

.divider--accent span {
  display: inline-block;
  width: 8px;
  height: 8px;
  background: var(--color-primary);
  border-radius: var(--radius-full);
  margin: 0 var(--space-4);
  flex-shrink: 0;
}

/* ==========================================================================
   Section 18: Component - Accordion
   ========================================================================== */

.accordion__trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-body);
  font-weight: var(--font-weight-medium);
  font-size: 1rem;
  color: var(--color-text-primary);
  padding: var(--space-4);
  cursor: pointer;
  background: none;
  border: none;
  width: 100%;
  text-align: left;
  transition: background var(--transition-fast);
}

.accordion__trigger:hover {
  background: var(--color-surface-alt);
}

.accordion__content {
  color: var(--color-text-secondary);
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: 0.9375rem;
  overflow: hidden;
  max-height: 0;
  transition: max-height var(--transition-fast);
}

.accordion__trigger.is-open + .accordion__content {
  max-height: 500px;
}

.accordion__icon {
  transition: transform var(--transition-fast);
}

.accordion__trigger.is-open .accordion__icon {
  transform: rotate(180deg);
}

/* ==========================================================================
   Section 19: Component - Carousel
   ========================================================================== */

.carousel {
  position: relative;
  overflow: hidden;
}

.carousel__track {
  display: flex;
  transition: transform var(--transition-slow);
}

.carousel__slide {
  flex-shrink: 0;
  width: 100%;
}

.carousel__nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--color-text-primary);
  transition: background var(--transition-fast), border-color var(--transition-fast);
  z-index: 2;
}

.carousel__nav:hover {
  background: var(--color-surface-alt);
  border-color: var(--color-border-strong);
}

.carousel__nav--prev {
  left: 8px;
}

.carousel__nav--next {
  right: 8px;
}

.carousel__dots {
  display: flex;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-4) 0;
}

.carousel__dot {
  width: 8px;
  height: 8px;
  border-radius: var(--radius-full);
  background: var(--color-border);
  border: none;
  cursor: pointer;
  transition: background var(--transition-fast);
}

.carousel__dot.is-active {
  background: var(--color-primary);
  transform: scale(1.25);
}

.carousel__dot:focus-visible {
  box-shadow: 0 0 0 2px var(--color-background), 0 0 0 4px var(--color-primary);
  outline: none;
}

/* ==========================================================================
   Section 20: Layout - Navigation Header
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--nav-height);
  background: rgba(255, 252, 247, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: box-shadow var(--transition-base);
}

.site-header.is-scrolled {
  box-shadow: var(--shadow-sm);
}

[data-theme="dark"] .site-header {
  background: rgba(28, 25, 23, 0.95);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .site-header {
    background: rgba(28, 25, 23, 0.95);
  }
}

.site-header__inner {
  max-width: var(--container-wide);
  margin: 0 auto;
  height: 100%;
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding-left: var(--margin-mobile);
  padding-right: var(--margin-mobile);
}

@media (min-width: 768px) {
  .site-header__inner {
    padding-left: var(--margin-tablet);
    padding-right: var(--margin-tablet);
  }
}

@media (min-width: 1024px) {
  .site-header__inner {
    padding-left: var(--margin-desktop);
    padding-right: var(--margin-desktop);
  }
}

.site-logo {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-bold);
  font-size: var(--text-h5-size);
  color: var(--color-text-primary);
  text-decoration: none;
  line-height: 1;
  margin-right: auto;
}

.site-logo:hover {
  text-decoration: none;
  color: var(--color-text-primary);
}

.nav-links {
  display: none;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: var(--space-6);
  align-items: center;
}

@media (min-width: 1024px) {
  .nav-links {
    display: flex;
  }
}

.nav-links a {
  font-family: var(--font-body);
  font-weight: var(--font-weight-medium);
  font-size: var(--text-body-size);
  color: var(--color-text-secondary);
  text-decoration: none;
  padding: var(--space-1) 0;
  transition: color var(--transition-fast);
}

.nav-links a:hover,
.nav-links a:focus {
  color: var(--color-text-primary);
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 2px;
  text-decoration-color: var(--color-primary);
}

.nav-links a.active {
  color: var(--color-text-primary);
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 2px;
  text-decoration-color: var(--color-primary);
}

.mobile-menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: transparent;
  border: none;
  color: var(--color-text-secondary);
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast), color var(--transition-fast);
}

.mobile-menu-toggle:hover {
  background: var(--color-surface-alt);
  color: var(--color-text-primary);
}

@media (min-width: 1024px) {
  .mobile-menu-toggle {
    display: none;
  }
}

/* ==========================================================================
   Section 21: Layout - Site Main Content
   ========================================================================== */

.site-main {
  min-height: calc(100vh - var(--nav-height));
}

/* ==========================================================================
   Section 22: Layout - Navigation Footer
   ========================================================================== */

.site-footer {
  background: var(--color-surface-alt);
  border-top: 1px solid var(--color-border);
  padding: var(--space-7) var(--margin-mobile);
}

@media (min-width: 768px) {
  .site-footer {
    padding-left: var(--margin-tablet);
    padding-right: var(--margin-tablet);
  }
}

@media (min-width: 1024px) {
  .site-footer {
    padding: var(--space-7) var(--margin-desktop);
  }
}

.site-footer__inner {
  max-width: var(--container-wide);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
  align-items: center;
  text-align: center;
}

@media (min-width: 1024px) {
  .site-footer__inner {
    flex-direction: row;
    justify-content: space-between;
    text-align: left;
  }

  .site-footer__section {
    flex: 1;
  }

  .site-footer__section--center {
    text-align: center;
  }

  .site-footer__section--right {
    text-align: right;
  }
}

.site-footer__heading {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-semibold);
  font-size: var(--text-body-lg-size);
  color: var(--color-text-primary);
}

.site-footer__nav {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
  justify-content: center;
}

.site-footer__nav a {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-sm-size);
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.site-footer__nav a:hover {
  color: var(--color-text-primary);
  text-decoration: underline;
}

.site-footer__copyright {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-sm-size);
  color: var(--color-text-muted);
}

/* ==========================================================================
   Section 23: Layout - Auth Buttons
   ========================================================================== */

.auth-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-body);
  font-weight: var(--font-weight-medium);
  font-size: var(--text-body-sm-size);
  padding: 6px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text-secondary);
  cursor: pointer;
  text-decoration: none;
  transition: border-color var(--transition-fast), background var(--transition-fast), color var(--transition-fast);
}

.auth-button:hover {
  border-color: var(--color-border-strong);
  background: var(--color-surface-alt);
  color: var(--color-text-primary);
}

.auth-email {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-sm-size);
  color: var(--color-text-secondary);
}

.auth-desktop {
  display: none;
  list-style: none;
  gap: var(--space-2);
  align-items: center;
}

@media (min-width: 1024px) {
  .auth-desktop {
    display: flex;
  }
}

.auth-mobile {
  display: flex;
  align-items: center;
  justify-content: center;
}

@media (min-width: 1024px) {
  .auth-mobile {
    display: none;
  }
}

.auth-button--compact {
  padding: 4px 10px;
  font-size: 0.8125rem;
}

/* Prevent desktop auth elements from rendering inside the mobile container */
#auth-header-mobile .auth-desktop {
  display: none !important;
}

/* Prevent mobile auth elements from rendering inside the desktop container */
#auth-header-section .auth-mobile {
  display: none !important;
}

/* ==========================================================================
   Section 23b: Component - User Menu Dropdown
   ========================================================================== */

.user-menu {
  position: relative;
}

.user-menu__trigger {
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
}

.user-menu__trigger::after {
  content: "\25BE";
  font-size: 0.625rem;
  margin-left: var(--space-1);
  transition: transform var(--transition-fast);
}

.user-menu.is-open .user-menu__trigger::after {
  transform: rotate(180deg);
}

/* When dropdown is open, connect trigger visually to the dropdown panel */
.user-menu.is-open .user-menu__trigger {
  background: var(--color-surface-alt);
  border-color: var(--color-border-strong);
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0;
}

.user-menu__dropdown {
  position: absolute;
  top: calc(100% - 1px);
  right: 0;
  min-width: 180px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-top-color: var(--color-border);
  border-radius: var(--radius-md);
  border-top-left-radius: 0;
  border-top-right-radius: 0;
  box-shadow: var(--shadow-lg);
  padding: var(--space-1) 0;
  z-index: 100;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition: opacity var(--transition-fast), visibility var(--transition-fast), transform var(--transition-fast);
}

.user-menu.is-open .user-menu__dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.user-menu .user-menu__item {
  display: block;
  width: 100%;
  text-align: left;
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-sm-size);
  color: var(--color-text-secondary);
  text-decoration: none;
  background: none;
  border: none;
  cursor: pointer;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.user-menu .user-menu__item:hover,
.user-menu .user-menu__item:focus-visible {
  background: var(--color-surface-alt);
  color: var(--color-text-primary);
  outline: none;
}

.user-menu .user-menu__item:focus-visible {
  box-shadow: inset 0 0 0 2px var(--color-primary);
}

.user-menu__separator {
  height: 1px;
  background: var(--color-border);
  margin: var(--space-1) 0;
}

.user-menu .user-menu__item--danger {
  color: var(--color-error);
}

.user-menu .user-menu__item--danger:hover,
.user-menu .user-menu__item--danger:focus-visible {
  color: var(--color-error);
  background: var(--color-error-bg);
}

.user-menu .user-menu__item--danger:focus-visible {
  box-shadow: inset 0 0 0 2px var(--color-error);
}

.user-menu .user-menu__item--admin {
  color: var(--color-primary);
  font-weight: var(--font-weight-medium);
}

.user-menu .user-menu__item--admin:hover,
.user-menu .user-menu__item--admin:focus-visible {
  background: var(--color-primary-subtle);
}

.user-menu .user-menu__item--admin:focus-visible {
  box-shadow: inset 0 0 0 2px var(--color-primary);
}

/* ==========================================================================
   Section 24: Layout - Mobile Navigation Drawer
   ========================================================================== */

.mobile-drawer {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: 300px;
  background: var(--color-surface);
  border-left: 1px solid var(--color-border);
  box-shadow: var(--shadow-xl);
  z-index: 60;
  transform: translateX(100%);
  transition: transform var(--transition-slow);
  padding: var(--space-6);
  overflow-y: auto;
}

.mobile-drawer.is-open {
  transform: translateX(0);
}

.mobile-drawer__overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  z-index: 55;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-slow);
}

.mobile-drawer__overlay.is-open {
  opacity: 1;
  pointer-events: auto;
}

.mobile-drawer__nav {
  list-style: none;
  margin: 0;
  margin-top: calc(var(--space-6) + var(--space-1));
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.mobile-drawer__nav a {
  display: block;
  font-family: var(--font-body);
  font-weight: var(--font-weight-medium);
  font-size: 1.125rem;
  color: var(--color-text-primary);
  text-decoration: none;
  padding: var(--space-4) var(--space-3);
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast), color var(--transition-fast);
}

.mobile-drawer__nav a:hover {
  background: var(--color-surface-alt);
  color: var(--color-primary);
}

.mobile-drawer__separator hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-2) 0;
}

.mobile-drawer__signout-btn {
  display: block;
  width: 100%;
  text-align: left;
  font-family: var(--font-body);
  font-weight: var(--font-weight-medium);
  font-size: 1.125rem;
  color: var(--color-error);
  text-decoration: none;
  padding: var(--space-4) var(--space-3);
  border-radius: var(--radius-sm);
  background: none;
  border: none;
  cursor: pointer;
  transition: background var(--transition-fast);
}

.mobile-drawer__signout-btn:hover {
  background: var(--color-error-bg);
}

.mobile-drawer__close {
  position: absolute;
  top: var(--space-3);
  right: var(--space-3);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: transparent;
  border: none;
  color: var(--color-text-secondary);
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background var(--transition-fast);
}

.mobile-drawer__close:hover {
  color: var(--color-text-primary);
  background: var(--color-surface-alt);
}

.mobile-drawer__close:focus-visible {
  outline: none;
  box-shadow: 0 0 0 2px var(--color-primary);
  color: var(--color-text-primary);
}

/* ==========================================================================
   Section 25: Component - Theme Toggle
   ========================================================================== */

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  color: var(--color-text-secondary);
  cursor: pointer;
  border-radius: var(--radius-sm);
  width: 44px;
  height: 44px;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.theme-toggle:hover {
  background: var(--color-surface-alt);
  color: var(--color-text-primary);
}

/* ==========================================================================
   Section 26: Component - Format Card
   ========================================================================== */

.format-card {
  text-align: center;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 32px 24px;
  background: var(--color-surface);
  box-shadow: var(--shadow-xs);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
}

.format-card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-sm);
  transform: translateY(-1px);
}

.format-card:focus-within {
  border-color: var(--color-primary);
}

.format-card__icon {
  font-size: 2rem;
  margin-bottom: var(--space-4);
}

.format-card__title {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-semibold);
  font-size: 1.25rem;
  color: var(--color-text-primary);
  margin-bottom: var(--space-4);
}

.format-card__features {
  list-style: none;
  margin: 0;
  padding: 0;
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  text-align: left;
}

.format-card__features li {
  padding: var(--space-2) 0;
}

.format-card__cta {
  margin-top: var(--space-5);
}

.format-card__cta .btn {
  width: 100%;
}

/* ==========================================================================
   Section 27: Component - Discount Grid
   ========================================================================== */

.discount-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
}

@media (min-width: 768px) {
  .discount-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (min-width: 1024px) {
  .discount-grid {
    grid-template-columns: 1fr 1fr 1fr;
  }
}

.discount-tier {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  text-align: center;
  transition: border-color var(--transition-fast), transform var(--transition-fast);
}

.discount-tier:hover {
  border-color: var(--color-border-strong);
  transform: translateY(-1px);
}

.discount-tier--highlight {
  border-color: var(--color-primary);
  background: var(--color-primary-subtle);
  box-shadow: var(--shadow-xs);
}

.discount-tier p {
  margin: var(--space-1) 0;
}

.discount-tier p:first-child {
  margin-top: 0;
}

.discount-tier p:last-child {
  margin-bottom: 0;
}

.discount-tier p:nth-child(2) {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-semibold);
  font-size: var(--text-h4-size);
  color: var(--color-text-primary);
}

/* ==========================================================================
   Section 28: Utility - Text Alignment, Color
   ========================================================================== */

.text-center {
  text-align: center;
}

.text-muted {
  color: var(--color-text-muted);
}

/* ==========================================================================
   Section 29: Component - 3-Column Grid
   ========================================================================== */

.grid--3col {
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  .grid--3col {
    grid-template-columns: 1fr 1fr 1fr;
  }
}

/* ==========================================================================
   Section 30: Component - Section Tagline
   ========================================================================== */

.section__tagline {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-lg-size);
  line-height: var(--text-body-lg-line-height);
  color: var(--color-text-secondary);
  max-width: var(--container-standard);
  margin-left: auto;
  margin-right: auto;
  margin-bottom: var(--space-7);
}

@media (max-width: 767px) {
  .section__tagline {
    margin-bottom: var(--space-5);
  }
}

/* ==========================================================================
   Section 31: Component - Comparison List (Old Rules vs New Rules)
   ========================================================================== */

.comparison__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin-top: var(--space-4);
}

.comparison__item {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-size);
  color: var(--color-text-secondary);
  padding-left: var(--space-5);
  position: relative;
}

.comparison__item::before {
  position: absolute;
  left: 0;
}

.comparison__item--old::before {
  content: "\2014";
  color: var(--color-text-muted);
}

.comparison__item--new::before {
  content: "\2713";
  color: var(--color-primary);
  font-weight: var(--font-weight-semibold);
}

/* ==========================================================================
   Section 32: Component - Learn List (What You'll Learn)
   ========================================================================== */

.learn-list {
  list-style: none;
  margin: 0;
  padding: 0;
  margin-top: var(--space-5);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.learn-list__item {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-lg-size);
  line-height: var(--text-body-lg-line-height);
  color: var(--color-text-primary);
  padding-left: var(--space-6);
  position: relative;
}

.learn-list__item::before {
  content: "\2713";
  position: absolute;
  left: 0;
  color: var(--color-primary);
  font-weight: var(--font-weight-semibold);
}

.learn-link {
  text-align: center;
  margin-top: var(--space-6);
}

.learn-link a {
  font-family: var(--font-body);
  font-weight: var(--font-weight-medium);
  color: var(--color-primary);
}

/* ==========================================================================
   Section 33: Component - CTA Subtitle
   ========================================================================== */

.cta__subtitle {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-size);
  color: var(--color-text-secondary);
  margin-top: var(--space-4);
  margin-bottom: var(--space-5);
}

/* ==========================================================================
   Section 34: Component - Testimonials Container
   ========================================================================== */

.testimonials-container {
  max-width: var(--container-wide);
  margin: 0 auto;
}

/* ==========================================================================
   Section 35: Component - About Page Prose
   ========================================================================== */

.about-page {
  padding-top: var(--space-9);
  padding-bottom: var(--space-9);
}

.body-lg {
  font-family: var(--font-body);
  font-weight: var(--text-body-lg-weight);
  font-size: var(--text-body-lg-size);
  line-height: var(--text-body-lg-line-height);
  letter-spacing: var(--text-body-lg-letter-spacing);
  color: var(--color-text-primary);
}

.text-secondary {
  color: var(--color-text-secondary);
}

.caption {
  font-family: var(--font-body);
  font-size: var(--text-caption-size);
  font-weight: var(--text-caption-weight);
  line-height: var(--text-caption-line-height);
  letter-spacing: var(--text-caption-letter-spacing);
}

.prose > * + * {
  margin-top: var(--space-5);
}

.prose > .blockquote {
  margin-top: var(--space-6);
  margin-bottom: var(--space-6);
}

.prose ul,
.prose ol {
  padding-left: var(--space-5);
}

.prose ul {
  list-style: disc;
}

.prose ol {
  list-style: decimal;
}

.prose li + li {
  margin-top: var(--space-2);
}

.prose li {
  color: var(--color-text-secondary);
  line-height: var(--text-body-lg-line-height);
}

/* Card content list styling */
.card ul,
.card ol {
  padding-left: var(--space-5);
  margin-top: var(--space-3);
}

.card ul {
  list-style: none;
  padding-left: 0;
}

.card ul li {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-size);
  color: var(--color-text-secondary);
  padding: var(--space-1) 0 var(--space-1) var(--space-5);
  position: relative;
}

.card ul li::before {
  content: "\2713";
  position: absolute;
  left: 0;
  color: var(--color-primary);
  font-weight: var(--font-weight-semibold);
}

.card ol {
  list-style: decimal;
}

.card ol li {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-size);
  color: var(--color-text-secondary);
  padding: var(--space-1) 0;
}

.card li + li {
  margin-top: var(--space-1);
}

.card--featured ol {
  list-style: decimal;
  padding-left: var(--space-5);
  margin-top: var(--space-4);
}

.card--featured ol li {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-size);
  color: var(--color-text-secondary);
  padding: var(--space-2) 0;
  line-height: var(--text-body-lg-line-height);
}

.card--featured ol li + li {
  margin-top: 0;
}

.card h3 + ul,
.card h3 + ol {
  margin-top: var(--space-4);
}

.card--featured h3 {
  margin-bottom: var(--space-3);
}

.card--featured h2 + * {
  margin-top: var(--space-4);
}

.card--featured p + .discount-grid {
  margin-top: var(--space-5);
}

.card--featured .discount-grid + h3 {
  margin-top: var(--space-6);
}

.about-cta .btn {
  margin-top: var(--space-5);
}

.publisher-credit {
  margin-top: var(--space-6);
}

/* ==========================================================================
   Section 36: Component - Carousel Image
   ========================================================================== */

.carousel__image {
  display: block;
  aspect-ratio: 3 / 4;
  max-width: 400px;
  width: 100%;
  height: auto;
  margin: 0 auto;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  object-fit: cover;
}

.carousel__nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--color-text-primary);
  box-shadow: var(--shadow-sm);
  transition: background var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
  z-index: 2;
}

.carousel__nav:hover {
  background: var(--color-surface-alt);
  border-color: var(--color-border-strong);
  box-shadow: var(--shadow-md);
}

.carousel__nav:focus-visible {
  box-shadow: 0 0 0 2px var(--color-background), 0 0 0 4px var(--color-primary);
  outline: none;
}

/* ==========================================================================
   Section 36b: Component - Book Hero Layout
   Book page hero with imagery + purchase options side by side on desktop.
   ========================================================================== */

.book-hero {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-7);
}

.book-hero__content {
  text-align: center;
}

.book-hero__imagery {
  width: 100%;
  max-width: 320px;
  flex-shrink: 0;
  margin: 0 auto;
}

/* Constrain carousel images within the book hero for a less dominant feel */
.book-hero .carousel__image {
  max-width: 300px;
}

.book-hero__subtitle {
  margin-top: var(--space-3);
  margin-bottom: var(--space-3);
}

/* -- Purchase Option Cards -- */

.book-hero__options {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3);
  margin-top: var(--space-6);
}

.book-hero__meta {
  margin-top: var(--space-4);
}

.book-hero__link {
  color: var(--color-primary);
  text-decoration: none;
}

.book-hero__link:hover {
  text-decoration: underline;
}

.book-option {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-5) var(--space-4);
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.book-option:hover {
  border-color: color-mix(in srgb, var(--color-primary) 40%, transparent);
  box-shadow: var(--shadow-sm);
}

.book-option--primary {
  border-color: var(--color-border-strong);
  background: var(--color-primary-subtle);
}

.book-option__format {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-semibold);
  font-size: 1.125rem;
  color: var(--color-text-primary);
  margin: 0;
}

.book-option__price {
  font-family: var(--font-body);
  font-weight: var(--font-weight-bold);
  font-size: 1.75rem;
  color: var(--color-text-primary);
  margin: var(--space-1) 0;
  line-height: 1.2;
}

.book-option__price--free {
  color: var(--color-primary);
}

.book-option .btn {
  width: 100%;
  margin-top: var(--space-2);
}

.card--featured__cta {
  margin-top: var(--space-6);
  text-align: center;
}

@media (min-width: 640px) {
  .book-hero__options {
    grid-template-columns: 1fr 1fr;
  }
}

@media (min-width: 1024px) {
  .book-hero {
    flex-direction: row;
    align-items: flex-start;
    gap: var(--space-8);
  }

  .book-hero__content {
    text-align: left;
    flex: 1;
    min-width: 0;
    order: 2;
  }

  .book-hero__imagery {
    max-width: 300px;
    margin: 0;
    order: 1;
  }
}

/* ==========================================================================
   Section 37: Utility - Body Small Text
   ========================================================================== */

.body-sm {
  font-family: var(--font-body);
  font-weight: var(--text-body-sm-weight);
  font-size: var(--text-body-sm-size);
  line-height: var(--text-body-sm-line-height);
  letter-spacing: var(--text-body-sm-letter-spacing);
  color: var(--color-text-primary);
}

/* ==========================================================================
   Section 38: Component - Modal Overlay & Dialog
   ========================================================================== */

.modal-overlay {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(28, 25, 23, 0.5);
  padding: var(--space-4);
  overflow-y: auto;
  animation: overlayFadeIn var(--transition-base) ease-out;
}

.modal {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  width: 100%;
  max-width: 560px;
  max-height: 90vh;
  overflow-y: auto;
  padding: var(--space-6);
  position: relative;
  animation: modalSlideIn var(--transition-base) ease-out;
}

@keyframes overlayFadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes modalSlideIn {
  from {
    opacity: 0;
    transform: scale(0.96) translateY(8px);
  }
  to {
    opacity: 1;
    transform: scale(1) translateY(0);
  }
}

.modal__title {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-semibold);
  font-size: var(--text-h3-size);
  color: var(--color-text-primary);
  margin-bottom: var(--space-5);
}

.modal__close {
  position: absolute;
  top: var(--space-4);
  right: var(--space-4);
  background: none;
  border: none;
  cursor: pointer;
  color: var(--color-text-muted);
  padding: var(--space-1);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast);
}

.modal__close:hover {
  color: var(--color-text-primary);
}

/* ==========================================================================
   Section 39: Component - Form Fields
   ========================================================================== */

.form-group {
  margin-bottom: var(--space-4);
}

.form-group label {
  display: block;
  font-family: var(--font-body);
  font-weight: var(--font-weight-medium);
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-1);
}

.form-input {
  width: 100%;
  box-sizing: border-box;
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: 1rem;
  padding: 12px 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-text-primary);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-primary) 20%, transparent);
}

.form-input::placeholder {
  color: var(--color-text-muted);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
}

@media (max-width: 639px) {
  .form-row {
    grid-template-columns: 1fr;
  }
}

.form-divider {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-5) 0;
}

.form-error {
  background: var(--color-error-bg);
  color: var(--color-error);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: 0.875rem;
  margin-bottom: var(--space-4);
  display: none;
}

.form-error.is-visible {
  display: block;
}

.form-success {
  background: var(--color-success-bg);
  color: var(--color-success);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: 0.875rem;
  margin-bottom: var(--space-4);
  display: none;
}

.form-success.is-visible {
  display: block;
}

.form-loading {
  text-align: center;
  padding: var(--space-3);
  font-family: var(--font-body);
  font-size: 0.875rem;
  color: var(--color-text-muted);
  display: none;
}

.form-loading.is-visible {
  display: block;
}

.collapsible-toggle {
  background: none;
  border: none;
  cursor: pointer;
  font-family: var(--font-body);
  font-weight: var(--font-weight-medium);
  font-size: 0.875rem;
  color: var(--color-primary);
  padding: 0;
  margin-bottom: var(--space-3);
  transition: color var(--transition-fast);
}

.collapsible-toggle:hover {
  color: var(--color-primary-hover);
  text-decoration: underline;
}

.collapsible-content {
  display: none;
}

.collapsible-content.is-open {
  display: block;
}

.shipping-estimate {
  font-family: var(--font-body);
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  padding: var(--space-3);
  background: var(--color-surface-alt);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-4);
  min-height: 1.5em;
}

.bulk-price-summary {
  background: var(--color-primary-subtle);
  border-radius: var(--radius-sm);
  padding: var(--space-4);
  margin-bottom: var(--space-5);
}

.bulk-price-summary p {
  font-family: var(--font-body);
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin: var(--space-1) 0;
}

.bulk-price-summary .bulk-total {
  font-weight: var(--font-weight-bold);
  font-size: 1.125rem;
  color: var(--color-text-primary);
  margin-top: var(--space-2);
}

.modal .btn {
  width: 100%;
}

/* ==========================================================================
   Section 40: Layout - Account Section
   ========================================================================== */

.account-layout {
  display: flex;
  min-height: calc(100vh - var(--nav-height));
}

.account-layout__sidebar {
  width: 240px;
  flex-shrink: 0;
  background: var(--color-surface);
  border-right: 1px solid var(--color-border);
}

.account-layout__content {
  flex: 1;
  min-width: 0;
}

@media (max-width: 1023px) {
  .account-layout {
    flex-direction: column;
  }

  .account-layout__sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid var(--color-border);
  }
}

/* ==========================================================================
   Section 41: Component - Account Sidebar Navigation
   ========================================================================== */

.account-sidebar {
  list-style: none;
  margin: 0;
  padding: 0;
}

.account-sidebar a {
  display: block;
  font-family: var(--font-body);
  font-weight: var(--font-weight-medium);
  font-size: var(--text-body-size);
  color: var(--color-text-secondary);
  text-decoration: none;
  padding: var(--space-3) var(--space-4);
  border-left: 2px solid transparent;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
}

.account-sidebar a:hover {
  background: var(--color-surface-alt);
  text-decoration: none;
}

.account-sidebar a.active {
  color: var(--color-text-primary);
  border-left-color: var(--color-primary);
}

@media (max-width: 1023px) {
  .account-sidebar {
    display: flex;
    overflow-x: auto;
  }

  .account-sidebar a {
    padding: var(--space-3) var(--space-4);
    border-left: none;
    border-bottom: 2px solid transparent;
    white-space: nowrap;
  }

  .account-sidebar a.active {
    border-left-color: transparent;
    border-bottom-color: var(--color-primary);
  }
}

.account-sidebar__heading {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-semibold);
  font-size: var(--text-h4-size);
  color: var(--color-text-primary);
  padding: var(--space-4);
  border-bottom: 1px solid var(--color-border);
}

.account-content {
  padding: var(--space-6);
  min-height: calc(100vh - var(--nav-height));
}

/* ==========================================================================
   Section 42: Component - Admin Stat Cards
   ========================================================================== */

.stat-card {
  display: flex;
  align-items: flex-start;
  gap: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: var(--space-6);
  box-shadow: var(--shadow-xs);
  transition: box-shadow 200ms ease-out, transform 200ms ease-out;
}

.stat-card:hover {
  box-shadow: var(--shadow-sm);
  transform: translateY(-1px);
}

a.stat-card {
  text-decoration: none;
  color: inherit;
  transition: box-shadow 200ms ease-out, transform 200ms ease-out, border-color var(--transition-fast);
}

a.stat-card:hover {
  border-color: color-mix(in srgb, var(--color-primary) 30%, transparent);
}

.stat-card__icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: var(--color-primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.stat-card__icon svg {
  color: var(--color-primary);
  width: 24px;
  height: 24px;
}

.stat-card__text {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-width: 0;
}

.stat-card__value {
  font-family: var(--font-body);
  font-weight: var(--font-weight-bold);
  font-size: 2rem;
  color: var(--color-text-primary);
  line-height: 1.2;
}

.stat-card__label {
  font-family: var(--font-body);
  font-weight: var(--text-body-sm-weight);
  font-size: var(--text-body-sm-size);
  line-height: var(--text-body-sm-line-height);
  color: var(--color-text-secondary);
  margin-top: var(--space-1);
}

.stat-card__detail {
  font-family: var(--font-body);
  font-weight: var(--text-caption-weight);
  font-size: var(--text-caption-size);
  line-height: var(--text-caption-line-height);
  color: var(--color-text-muted);
  margin-top: var(--space-1);
}

/* ==========================================================================
   Section 43: Component - Admin Data Tables
   ========================================================================== */

.data-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  font-family: var(--font-body);
}

.data-table thead {
  background: var(--color-surface-alt);
}

.data-table th {
  font-family: var(--font-body);
  font-weight: var(--font-weight-semibold);
  font-size: 0.75rem;
  line-height: var(--text-body-sm-line-height);
  color: var(--color-text-secondary);
  text-align: left;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: var(--space-3) var(--space-4);
}

.data-table td {
  padding: var(--space-3) var(--space-4);
  vertical-align: top;
  border-bottom: 1px solid var(--color-border);
  font-size: var(--text-body-sm-size);
  color: var(--color-text-primary);
}

.data-table tbody tr {
  transition: background var(--transition-fast);
}

.data-table tbody tr:hover {
  background: var(--color-surface-alt);
}

.data-table__row {
  /* Individual row class for htmx targeting (id attribute on <tr>) */
}

@media (max-width: 767px) {
  .data-table thead {
    display: none;
  }

  .data-table tbody tr {
    display: block;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    margin-bottom: var(--space-3);
    padding: var(--space-3) var(--space-4);
  }

  .data-table tbody tr:hover {
    background: var(--color-surface);
  }

  .data-table td {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    padding: var(--space-2) 0;
    border-bottom: none;
    font-size: var(--text-body-sm-size);
  }

  .data-table td::before {
    content: attr(data-label);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-secondary);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    flex-shrink: 0;
    margin-right: var(--space-4);
  }

  .data-table td:last-child {
    padding-bottom: 0;
  }
}

/* ==========================================================================
   Section 44: Component - Admin Action Buttons
   ========================================================================== */

.btn--icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  background: transparent;
  color: var(--color-text-secondary);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.btn--icon:hover {
  background: var(--color-surface-alt);
  color: var(--color-text-primary);
}

.btn--icon:focus-visible {
  box-shadow: 0 0 0 2px var(--color-background), 0 0 0 4px var(--color-primary);
  outline: none;
}

.admin-actions {
  display: flex;
  gap: var(--space-2);
  align-items: center;
}

.inline-form {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.inline-form input,
.inline-form select {
  font-family: var(--font-body);
  font-size: 0.8125rem;
  padding: 8px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-text-primary);
  transition: border-color var(--transition-fast);
}

.inline-form input:focus,
.inline-form select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-primary) 20%, transparent);
}

/* ==========================================================================
   Section 45: Component - Admin Badge Variants
   ========================================================================== */

.badge--info {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

.badge--shipped {
  background: var(--color-shipped-bg);
  color: var(--color-shipped-text);
}

/* ==========================================================================
   Section 46: Component - htmx Loading Indicators
   ========================================================================== */

.htmx-indicator {
  opacity: 0;
  height: 0;
  overflow: hidden;
  transition: opacity 200ms ease-out;
}

.htmx-indicator.htmx-swapping {
  opacity: 1;
  height: auto;
}

.htmx-request .htmx-indicator {
  opacity: 1;
  height: auto;
}

/* ==========================================================================
   Section 47: Component - Admin Section Layout
   ========================================================================== */

.admin-section {
  margin-bottom: var(--space-7);
}

.admin-section__heading {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-semibold);
  font-size: var(--text-h3-size);
  line-height: var(--text-h3-line-height);
  letter-spacing: var(--text-h3-letter-spacing);
  color: var(--color-text-primary);
  margin-bottom: var(--space-4);
}

.admin-section__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}

.admin-section__actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* ==========================================================================
   Section 48: Component - Empty State
   ========================================================================== */

.empty-state {
  text-align: center;
  padding: var(--space-7) 0;
}

.empty-state__icon {
  width: 48px;
  height: 48px;
  color: var(--color-text-muted);
  margin: 0 auto var(--space-4);
}

.empty-state__text {
  font-family: var(--font-body);
  font-weight: var(--font-weight-normal);
  font-size: var(--text-body-size);
  color: var(--color-text-secondary);
}