/* === CSS Custom Properties === */
:root {
  --color-bg: #ffffff;
  --color-surface: #f9fafb;
  --color-text: #1f2937;
  --color-text-muted: #6b7280;
  --color-accent: #4f46e5;
  --color-accent-light: #eef2ff;
  --color-accent-hover: #4338ca;
  --color-border: #e5e7eb;
  --color-code-bg: #f3f4f6;
  --color-warning: #92400e;
  --color-warning-bg: #fffbeb;
  --color-warning-border: #f59e0b;
  --color-tip: #065f46;
  --color-tip-bg: #ecfdf5;
  --color-tip-border: #10b981;
  --color-philosophy: #312e81;
  --color-philosophy-bg: #eef2ff;
  --color-philosophy-border: #6366f1;
  --color-nav-bg: #f9fafb;
  --color-nav-text: #4b5563;
  --color-nav-active: #4f46e5;
  --color-rule: #d1d5db;

  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  --font-size-base: 16px;
  --line-height: 1.7;
  --max-width: 720px;
  --nav-width: 220px;

  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 3rem;

  --radius-sm: 4px;
  --radius-md: 8px;
}

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

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

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* === Base Typography === */
html {
  font-size: var(--font-size-base);
}

body {
  font-family: var(--font-body);
  line-height: var(--line-height);
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

h1 {
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--space-sm);
  color: var(--color-text);
}

.subtitle {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-xl);
  line-height: 1.6;
}

h2 {
  font-size: 1.35rem;
  font-weight: 600;
  line-height: 1.3;
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
  color: var(--color-text);
  padding-left: 0.75rem;
  border-left: 3px solid var(--color-accent);
}

h3 {
  font-size: 1.1rem;
  font-weight: 600;
  line-height: 1.4;
  margin-top: var(--space-lg);
  margin-bottom: var(--space-sm);
}

p {
  margin-bottom: var(--space-md);
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color 0.15s;
}

a:hover {
  color: var(--color-accent-hover);
  text-decoration: underline;
}

ul, ol {
  margin-bottom: var(--space-md);
  padding-left: 1.5rem;
}

li {
  margin-bottom: var(--space-xs);
}

strong {
  font-weight: 600;
}

em {
  font-style: normal;
  color: var(--color-accent);
  font-weight: 600;
}

/* === Layout === */
.page-wrapper {
  display: flex;
  min-height: 100vh;
}

/* === Sidebar Nav === */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--nav-width);
  height: 100vh;
  overflow-y: auto;
  padding: var(--space-lg) var(--space-md);
  background: var(--color-nav-bg);
  border-right: 1px solid var(--color-border);
  z-index: 100;
}

.nav-brand {
  margin-bottom: var(--space-lg);
  padding: 0 var(--space-sm);
}

.nav-title {
  display: block;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.3;
}

.nav-subtitle {
  display: block;
  font-size: 0.7rem;
  color: var(--color-text-muted);
  margin-top: var(--space-xs);
}

.nav-links {
  list-style: none;
  padding: 0;
}

.nav-links li {
  margin-bottom: 1px;
}

.nav-links a {
  display: block;
  padding: 0.5rem 0.6rem;
  font-size: 0.8125rem;
  font-weight: 450;
  color: var(--color-nav-text);
  border-radius: var(--radius-sm);
  transition: all 0.15s;
  text-decoration: none;
}

.nav-links a:hover {
  color: var(--color-text);
  background: rgba(0, 0, 0, 0.04);
  text-decoration: none;
}

.nav-links a.nav-active {
  color: var(--color-nav-active);
  background: var(--color-accent-light);
  font-weight: 600;
}

/* === Main Content === */
.content {
  margin-left: var(--nav-width);
  flex: 1;
  padding: var(--space-xl) var(--space-xl);
  max-width: calc(var(--max-width) + 2 * var(--space-xl));
}

/* === Callout Boxes === */
.callout {
  padding: var(--space-lg);
  margin: var(--space-lg) 0;
  border-radius: var(--radius-md);
  border-left: 3px solid;
  font-size: 0.9375rem;
}

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

.callout-philosophy {
  background: var(--color-philosophy-bg);
  border-left-color: var(--color-philosophy-border);
  color: var(--color-philosophy);
}

.callout-warning {
  background: var(--color-warning-bg);
  border-left-color: var(--color-warning-border);
  color: var(--color-warning);
}

.callout-tip {
  background: var(--color-tip-bg);
  border-left-color: var(--color-tip-border);
  color: var(--color-tip);
}

.callout-label {
  display: block;
  font-weight: 600;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-sm);
}

/* === Code Blocks === */
code {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  background: var(--color-code-bg);
  padding: 0.15em 0.4em;
  border-radius: 3px;
}

.code-block {
  margin: var(--space-lg) 0;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--color-border);
}

.code-header {
  background: #f3f4f6;
  padding: var(--space-sm) var(--space-md);
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: 1px solid var(--color-border);
}

.code-block pre {
  margin: 0;
  padding: var(--space-md) var(--space-lg);
  background: #1e293b;
  overflow-x: auto;
}

.code-block code {
  background: none;
  padding: 0;
  border: none;
  font-size: 0.8125rem;
  line-height: 1.6;
  color: #e2e8f0;
}

/* === Screenshot Placeholders === */
.screenshot {
  margin: var(--space-lg) 0;
}

.screenshot img {
  width: 100%;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

.screenshot-placeholder {
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  padding: 3rem 2rem;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  min-height: 180px;
  justify-content: center;
}

.screenshot-placeholder .screenshot-label {
  font-weight: 500;
  color: var(--color-text-muted);
  font-size: 0.875rem;
}

.screenshot-placeholder .screenshot-filename {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-muted);
  opacity: 0.6;
}

figcaption {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  margin-top: var(--space-sm);
  text-align: center;
}

/* === Workflow Diagram === */
.workflow-diagram {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
  margin: var(--space-lg) 0;
  padding: var(--space-lg);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.workflow-step {
  padding: 0.6rem 1.5rem;
  background: var(--color-accent-light);
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.9rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-accent);
  text-align: center;
}

.workflow-step-repeat {
  background: var(--color-surface);
  color: var(--color-text-muted);
  border-color: var(--color-border);
  font-weight: 500;
}

.workflow-arrow {
  color: var(--color-text-muted);
  font-size: 1.2rem;
  line-height: 1;
  padding: 0.25rem 0;
}

/* === Taxonomy Grid === */
.taxonomy-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-sm);
  margin: var(--space-lg) 0;
}

.taxonomy-card {
  padding: 0.75rem 1rem;
  background: var(--color-surface);
  border-left: 3px solid var(--color-accent);
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  line-height: 1.5;
}

.taxonomy-card strong {
  color: var(--color-accent);
}

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

/* === Page Navigation (prev/next) === */
.page-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
}

.page-nav a {
  font-size: 0.875rem;
  font-weight: 500;
}

.page-nav .next {
  margin-left: auto;
}

/* === Kicker (small uppercase label above h1) === */
.kicker {
  font-size: 0.78rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
}

/* === Footer === */
.page-footer {
  margin-top: var(--space-lg);
  padding-top: var(--space-md);
  font-size: 0.75rem;
  color: var(--color-text-muted);
  opacity: 0.6;
}

.footer-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-md);
  border-top: 1px solid var(--color-rule);
  padding: var(--space-md) 0;
  margin-top: var(--space-xl);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-text-muted);
}

/* === Comparison Grid (bad/good prompts) === */
.comparison-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
  margin: var(--space-lg) 0;
}

.comparison-grid .bad,
.comparison-grid .good {
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  font-size: 0.875rem;
}

.comparison-grid .bad {
  background: #fef2f2;
  border: 1px solid #fecaca;
}

.comparison-grid .good {
  background: #f0fdf4;
  border: 1px solid #bbf7d0;
}

.comparison-grid .label {
  display: block;
  font-weight: 600;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-sm);
}

.comparison-grid .bad .label {
  color: #991b1b;
}

.comparison-grid .good .label {
  color: #166534;
}

/* === Hero section for page 1 === */
.hero {
  padding: var(--space-xl) 0;
  margin-bottom: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
}

/* === Mobile Nav (details/summary) === */
.mobile-nav {
  display: none;
}

/* === Responsive === */
@media (max-width: 768px) {
  .site-nav {
    display: none;
  }

  .mobile-nav {
    display: block;
    position: sticky;
    top: 0;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-sm) var(--space-md);
    z-index: 100;
  }

  .mobile-nav summary {
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    padding: var(--space-sm) 0;
    color: var(--color-text);
  }

  .mobile-nav .nav-links a {
    color: var(--color-nav-text);
    padding: 0.5rem 0;
  }

  .mobile-nav .nav-links a.nav-active {
    color: var(--color-nav-active);
  }

  .content {
    margin-left: 0;
    padding: var(--space-lg) var(--space-md);
  }

  h1 {
    font-size: 1.75rem;
  }

  h2 {
    font-size: 1.2rem;
  }

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

/* === Print === */
@media print {
  .site-nav,
  .mobile-nav,
  .page-nav {
    display: none;
  }

  .page-wrapper {
    display: block;
    max-width: none;
    padding: 0;
  }

  .content {
    margin-left: 0;
    max-width: 100%;
    padding: 0;
  }

  .callout {
    border: 1px solid #ccc;
    background: none !important;
    page-break-inside: avoid;
  }

  h1, h2, h3 {
    page-break-after: avoid;
  }

  .footer-meta {
    border-color: #999;
  }

  body {
    background: white;
    color: black;
  }

  a {
    color: inherit;
    text-decoration: underline;
  }
}