/* PromptImageLab Design System Tokens & Base Stylesheet
   Strict, Restrained, Monochromatic, Enterprise Engineering Standard
   Tokens: #FFFFFF (bg), #171717 (primary text/action), #626262 (secondary text),
           #E5E5E5 (borders), #F7F7F7 (subtle surface)
   Prohibited: Rainbow palettes, gradients, glows, emojis, decorative icons */

:root {
  /* Strict Neutral Palette */
  --bg-primary: #ffffff;
  --bg-secondary: #f7f7f7;
  --bg-tertiary: #efefef;
  --bg-card: #ffffff;
  
  --text-primary: #171717;
  --text-secondary: #626262;
  --text-muted: #767676;
  --text-faint: #a3a3a3;
  
  --border-subtle: #e5e5e5;
  --border-medium: #d4d4d4;
  --border-dark: #171717;
  
  /* Single Restrained Accent */
  --accent-primary: #171717;
  --accent-hover: #000000;
  --accent-light: #f7f7f7;
  --accent-border: #e5e5e5;
  
  /* Semantic Status Indicators (Subtle & High Contrast) */
  --success-text: #166534;
  --success-bg: #f0fdf4;
  --success-border: #bbf7d0;
  
  --danger-text: #991b1b;
  --danger-bg: #fef2f2;
  --danger-border: #fecaca;
  
  --warning-text: #854d0e;
  --warning-bg: #fefce8;
  --warning-border: #fef08a;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Consolas, Menlo, Monaco, monospace;

  /* Layout & Geometry */
  --max-width: 1140px;
  --max-width-narrow: 840px;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  
  /* Elevation */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-focus: 0 0 0 2px #ffffff, 0 0 0 4px #171717;
}

/* Reset & Box Sizing */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-sans);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  font-size: 16px;
  line-height: 1.6;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-primary);
  color: var(--text-primary);
}

/* Skip link for accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 10px;
  background: var(--text-primary);
  color: #fff;
  padding: 8px 14px;
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  z-index: 1000;
  transition: top 0.15s;
}
.skip-link:focus {
  top: 10px;
}

/* Focus Outlines */
a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: none;
  box-shadow: var(--shadow-focus);
}

/* Links */
a {
  color: var(--text-primary);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: opacity 0.15s;
}
a:hover {
  opacity: 0.8;
}

/* Typography Hierarchy */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-primary);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.025em;
}

h1 { font-size: 2.25rem; margin-bottom: 0.75rem; }
h2 { font-size: 1.5rem; margin-top: 2rem; margin-bottom: 0.75rem; }
h3 { font-size: 1.15rem; margin-top: 1.25rem; margin-bottom: 0.5rem; }
h4 { font-size: 1rem; margin-top: 1rem; margin-bottom: 0.5rem; }

p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}
p.lead {
  font-size: 1.125rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 1.5rem;
}

.eyebrow {
  display: block;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
}

code, kbd, samp, pre {
  font-family: var(--font-mono);
  font-size: 0.875em;
}

code {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
}

pre {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1rem;
  overflow-x: auto;
  margin: 1rem 0;
  line-height: 1.5;
}
pre code {
  background: none;
  padding: 0;
  border: none;
}

/* Layout Container */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}
.container-narrow {
  max-width: var(--max-width-narrow);
}

/* Header & Navigation */
.site-header {
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-subtle);
  position: sticky;
  top: 0;
  z-index: 100;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.site-brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: var(--text-primary);
}
.site-brand:hover {
  text-decoration: none;
  opacity: 1;
}
.brand-name {
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.03em;
  color: var(--text-primary);
}
.site-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}
.nav-link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  padding: 0.35rem 0;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}
.nav-link:hover {
  color: var(--text-primary);
  text-decoration: none;
  opacity: 1;
}
.nav-link.active {
  color: var(--text-primary);
  border-bottom-color: var(--text-primary);
}
.mobile-nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 6px 10px;
  color: var(--text-primary);
  cursor: pointer;
  font-size: 0.85rem;
}

/* Breadcrumbs */
.breadcrumbs {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.4rem;
  font-size: 0.825rem;
  color: var(--text-muted);
  margin-top: 1rem;
  margin-bottom: 1.25rem;
}
.breadcrumbs a {
  color: var(--text-secondary);
  text-decoration: none;
}
.breadcrumbs a:hover {
  color: var(--text-primary);
  text-decoration: underline;
}
.breadcrumb-separator {
  color: var(--text-faint);
}

/* Page Shell & Main */
main.page-main {
  flex: 1;
  padding-top: 1.5rem;
  padding-bottom: 4rem;
}

/* Page Titles */
.page-header {
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 1.5rem;
}
.page-title {
  margin-bottom: 0.5rem;
}
.page-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.825rem;
  color: var(--text-muted);
  margin-top: 0.5rem;
}

/* Cards & Grid */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}
.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  transition: border-color 0.15s, box-shadow 0.15s;
  display: flex;
  flex-direction: column;
}
.card:hover {
  border-color: var(--border-medium);
  box-shadow: var(--shadow-sm);
}
.card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 0.6rem;
}
.card-badge {
  font-size: 0.725rem;
  font-weight: 600;
  color: var(--text-secondary);
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 0.125rem 0.45rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.card-title {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
}
.card-title a {
  color: var(--text-primary);
  text-decoration: none;
}
.card-title a:hover {
  color: var(--text-primary);
  text-decoration: underline;
}
.card-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 1.25rem;
  flex: 1;
}
.card-footer {
  margin-top: auto;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border-subtle);
  font-size: 0.85rem;
}

/* Callouts & Information Disclosures */
.callout {
  padding: 1rem 1.25rem;
  border-radius: var(--radius-md);
  margin: 1.25rem 0;
  border: 1px solid;
  font-size: 0.9rem;
  line-height: 1.5;
}
.callout-info {
  background-color: var(--bg-secondary);
  border-color: var(--border-medium);
  color: var(--text-primary);
}
.callout-warning {
  background-color: var(--warning-bg);
  border-color: var(--warning-border);
  color: var(--warning-text);
}
.callout-note {
  background-color: var(--bg-secondary);
  border-color: var(--border-subtle);
  color: var(--text-secondary);
}
.callout-title {
  font-weight: 600;
  margin-bottom: 0.25rem;
  color: var(--text-primary);
}

/* Form Controls */
.form-group {
  margin-bottom: 1.25rem;
}
.form-label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.35rem;
}
.form-hint {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 0.3rem;
}
.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: 0.6rem 0.75rem;
  font-family: inherit;
  font-size: 0.9rem;
  color: var(--text-primary);
  background-color: #fff;
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-sm);
  transition: border-color 0.15s, box-shadow 0.15s;
}
.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  border-color: var(--text-primary);
  outline: none;
  box-shadow: 0 0 0 1px var(--text-primary);
}
.form-textarea {
  resize: vertical;
  min-height: 100px;
}
.form-row {
  display: flex;
  gap: 1rem;
}
.form-row > .form-group {
  flex: 1;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-family: inherit;
  font-size: 0.875rem;
  font-weight: 600;
  padding: 0.55rem 1.15rem;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: background-color 0.15s, border-color 0.15s, color 0.15s;
}
.btn:hover {
  text-decoration: none;
}
.btn-primary {
  background-color: var(--text-primary);
  color: #ffffff;
  border-color: var(--text-primary);
}
.btn-primary:hover {
  background-color: #000000;
  border-color: #000000;
}
.btn-secondary {
  background-color: #ffffff;
  color: var(--text-primary);
  border-color: var(--border-medium);
}
.btn-secondary:hover {
  background-color: var(--bg-secondary);
  border-color: var(--border-dark);
}
.btn-sm {
  padding: 0.35rem 0.75rem;
  font-size: 0.8rem;
}

/* Tool Interactive Shell */
.tool-shell {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow-sm);
}
.tool-output-panel {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 1.25rem;
  margin-top: 1.25rem;
}
.tool-output-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}
.tool-output-title {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}
.tool-output-content {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--text-primary);
  background: #fff;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 1rem;
  min-height: 80px;
  white-space: pre-wrap;
  word-break: break-word;
}

/* Badges & Pills */
.badge {
  display: inline-flex;
  align-items: center;
  font-size: 0.725rem;
  font-weight: 600;
  padding: 0.15rem 0.45rem;
  border-radius: var(--radius-sm);
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
}

/* Tables */
.table-container {
  overflow-x: auto;
  margin: 1.25rem 0;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
}
table.data-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.875rem;
}
table.data-table th {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  font-weight: 600;
  padding: 0.65rem 0.85rem;
  border-bottom: 1px solid var(--border-subtle);
}
table.data-table td {
  padding: 0.65rem 0.85rem;
  border-bottom: 1px solid var(--border-subtle);
  color: var(--text-secondary);
}
table.data-table tr:last-child td {
  border-bottom: none;
}
table.data-table tr:hover td {
  background-color: var(--bg-secondary);
}

/* Article / Longform Content */
.article-content {
  color: var(--text-secondary);
  line-height: 1.65;
}
.article-content h2 {
  color: var(--text-primary);
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 0.35rem;
  margin-top: 2rem;
}
.article-content ul, 
.article-content ol {
  margin: 1rem 0 1.25rem 1.5rem;
}
.article-content li {
  margin-bottom: 0.4rem;
}

/* Footer */
.site-footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
  padding: 3rem 0 2rem;
  margin-top: auto;
  font-size: 0.85rem;
  color: var(--text-muted);
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2.5rem;
  margin-bottom: 2rem;
}
.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.footer-brand p {
  color: var(--text-muted);
  font-size: 0.85rem;
  line-height: 1.5;
  max-width: 320px;
}
.footer-heading {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-primary);
  margin-bottom: 0.85rem;
}
.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}
.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
}
.footer-links a:hover {
  color: var(--text-primary);
  text-decoration: underline;
}
.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border-subtle);
  font-size: 0.8rem;
  color: var(--text-muted);
  flex-wrap: wrap;
  gap: 1rem;
}

/* Responsive Media Queries */
@media (max-width: 900px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.3rem; }
  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .mobile-nav-toggle {
    display: block;
  }
  .site-nav {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: #fff;
    border-bottom: 1px solid var(--border-subtle);
    flex-direction: column;
    padding: 1.25rem;
    gap: 0.85rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
  }
  .site-nav.open {
    display: flex;
  }
  .form-row {
    flex-direction: column;
    gap: 0;
  }
}