/**
 * VALIDKERNEL DESIGN SYSTEM
 * Document ID: VK-CSS-2026-001
 * Authority: L0 Governance
 * Status: MATERIALIZED
 * 
 * Deterministic Trust Infrastructure
 * Boring by design. Predictable. Deterministic. Trustworthy.
 */

/* ==========================================================================
   1. CSS CUSTOM PROPERTIES (DESIGN TOKENS)
   Per VK-BRAND-2025-001 — Only approved colors permitted
   ========================================================================== */

:root {
  /* Colors — ONLY these three colors are authorized */
  --vk-primary: #000000;
  --vk-secondary: #1A1A2E;
  --vk-background: #FFFFFF;
  
  /* Semantic colors for UI states */
  --vk-success: #22c55e;
  --vk-warning: #eab308;
  --vk-error: #ef4444;
  --vk-info: #3b82f6;
  
  /* Typography — Per brand standards */
  --vk-font-header: 'JetBrains Mono', 'IBM Plex Mono', monospace;
  --vk-font-body: 'Inter', 'SF Pro', -apple-system, BlinkMacSystemFont, sans-serif;
  
  /* Type Scale — Per VK-BRAND-2025-001 Section 4 */
  --vk-text-h1: 48px;
  --vk-text-h2: 36px;
  --vk-text-h3: 28px;
  --vk-text-h4: 22px;
  --vk-text-body: 16px;
  --vk-text-caption: 14px;
  --vk-text-small: 12px;
  
  /* Line Heights */
  --vk-line-h1: 56px;
  --vk-line-h2: 44px;
  --vk-line-h3: 34px;
  --vk-line-h4: 28px;
  --vk-line-body: 24px;
  --vk-line-caption: 20px;
  
  /* Spacing — 24px baseline grid */
  --vk-space-1: 4px;
  --vk-space-2: 8px;
  --vk-space-3: 12px;
  --vk-space-4: 16px;
  --vk-space-5: 20px;
  --vk-space-6: 24px;
  --vk-space-8: 32px;
  --vk-space-10: 40px;
  --vk-space-12: 48px;
  --vk-space-16: 64px;
  --vk-space-20: 80px;
  --vk-space-24: 96px;
  
  /* Layout — Per VK-BRAND-2025-001 Section 5 */
  --vk-page-padding: 48px;
  --vk-gutter: 24px;
  --vk-max-width: 1200px;
  --vk-border-width: 1px;
  
  /* Transitions — Minimal, no animations */
  --vk-transition: 150ms ease;
}

/* ==========================================================================
   2. RESET & BASE STYLES
   ========================================================================== */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  font-family: var(--vk-font-body);
  font-size: var(--vk-text-body);
  line-height: var(--vk-line-body);
  color: var(--vk-primary);
  background-color: var(--vk-background);
  min-height: 100vh;
}

/* ==========================================================================
   3. TYPOGRAPHY
   Headers: JetBrains Mono, ALL CAPS
   Body: Inter, regular
   ========================================================================== */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--vk-font-header);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  color: var(--vk-primary);
}

h1 {
  font-size: var(--vk-text-h1);
  line-height: var(--vk-line-h1);
  margin-bottom: var(--vk-space-6);
}

h2 {
  font-size: var(--vk-text-h2);
  line-height: var(--vk-line-h2);
  margin-bottom: var(--vk-space-6);
}

h3 {
  font-size: var(--vk-text-h3);
  line-height: var(--vk-line-h3);
  font-weight: 500;
  margin-bottom: var(--vk-space-4);
}

h4 {
  font-size: var(--vk-text-h4);
  line-height: var(--vk-line-h4);
  font-weight: 500;
  margin-bottom: var(--vk-space-4);
}

p {
  margin-bottom: var(--vk-space-4);
  max-width: 65ch;
}

a {
  color: var(--vk-secondary);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--vk-transition);
}

a:hover {
  border-bottom-color: var(--vk-secondary);
}

code, pre, .vk-font-mono {
  font-family: var(--vk-font-header);
  font-size: 0.875em;
}

pre {
  background: var(--vk-secondary);
  color: var(--vk-background);
  padding: var(--vk-space-6);
  overflow-x: auto;
  margin-bottom: var(--vk-space-6);
}

/* ==========================================================================
   4. LAYOUT SYSTEM
   48px padding, 24px gutter, 2-column grid
   ========================================================================== */

.vk-container {
  max-width: var(--vk-max-width);
  margin: 0 auto;
  padding: 0 var(--vk-page-padding);
}

.vk-section {
  padding: var(--vk-space-24) 0;
}

.vk-section-header {
  margin-bottom: var(--vk-space-12);
}

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

.vk-grid-2 {
  grid-template-columns: repeat(2, 1fr);
}

.vk-grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.vk-grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

.vk-grid-auto {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

/* ==========================================================================
   5. NAVIGATION
   Header bar in primary black
   ========================================================================== */

.vk-nav {
  background: var(--vk-primary);
  color: var(--vk-background);
  padding: var(--vk-space-4) 0;
  position: sticky;
  top: 0;
  z-index: 1000;
}

.vk-nav-inner {
  max-width: var(--vk-max-width);
  margin: 0 auto;
  padding: 0 var(--vk-page-padding);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.vk-logo {
  display: flex;
  align-items: center;
  gap: var(--vk-space-3);
  font-family: var(--vk-font-header);
  font-size: var(--vk-text-caption);
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--vk-background);
  border-bottom: none;
}

.vk-logo:hover {
  border-bottom: none;
}

.vk-logo-mark {
  width: 24px;
  height: 24px;
  background: var(--vk-background);
}

.vk-nav-menu {
  display: flex;
  list-style: none;
  gap: var(--vk-space-1);
}

.vk-nav-item {
  position: relative;
}

.vk-nav-link {
  display: flex;
  align-items: center;
  gap: var(--vk-space-2);
  padding: var(--vk-space-2) var(--vk-space-4);
  color: var(--vk-background);
  font-size: var(--vk-text-small);
  font-weight: 500;
  border-bottom: none;
  transition: background var(--vk-transition);
}

.vk-nav-link:hover {
  background: var(--vk-secondary);
  border-bottom: none;
}

.vk-chevron {
  width: 12px;
  height: 12px;
  transition: transform var(--vk-transition);
}

.vk-nav-item:hover .vk-chevron {
  transform: rotate(180deg);
}

/* Dropdown */
.vk-dropdown {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 280px;
  background: var(--vk-background);
  border: var(--vk-border-width) solid var(--vk-primary);
  padding: var(--vk-space-4);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: all var(--vk-transition);
}

.vk-nav-item:hover .vk-dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.vk-dropdown-label {
  display: block;
  font-family: var(--vk-font-header);
  font-size: var(--vk-text-small);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--vk-secondary);
  padding: var(--vk-space-2) var(--vk-space-3);
  margin-top: var(--vk-space-2);
}

.vk-dropdown-label:first-child {
  margin-top: 0;
}

.vk-dropdown-item {
  display: block;
  padding: var(--vk-space-2) var(--vk-space-3);
  color: var(--vk-primary);
  font-size: var(--vk-text-caption);
  border-bottom: none;
  transition: background var(--vk-transition);
}

.vk-dropdown-item:hover {
  background: rgba(26, 26, 46, 0.05);
  border-bottom: none;
}

.vk-dropdown-divider {
  height: 1px;
  background: rgba(0, 0, 0, 0.1);
  margin: var(--vk-space-3) 0;
}

/* Mobile menu button */
.vk-menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--vk-background);
  padding: var(--vk-space-2);
  cursor: pointer;
}

/* Mobile menu styles */
@media (max-width: 768px) {
  .vk-nav-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--vk-primary);
    flex-direction: column;
    padding: var(--vk-space-4);
    gap: 0;
  }
  
  .vk-nav-menu.vk-nav-menu-open {
    display: flex;
  }
  
  .vk-nav-item {
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  }
  
  .vk-nav-item:last-child {
    border-bottom: none;
  }
  
  .vk-nav-link {
    padding: var(--vk-space-4);
    width: 100%;
    justify-content: space-between;
  }
  
  .vk-dropdown {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    border: none;
    background: rgba(255, 255, 255, 0.05);
    display: none;
    min-width: 100%;
  }
  
  .vk-nav-item.vk-dropdown-open .vk-dropdown {
    display: block;
  }
  
  .vk-nav-item:hover .vk-dropdown {
    display: block;
  }
  
  .vk-dropdown-item {
    color: var(--vk-background);
    padding: var(--vk-space-3) var(--vk-space-4);
  }
  
  .vk-dropdown-item:hover {
    background: rgba(255, 255, 255, 0.1);
  }
  
  .vk-dropdown-label {
    color: rgba(255, 255, 255, 0.6);
  }
  
  .vk-dropdown-divider {
    background: rgba(255, 255, 255, 0.1);
  }
  
  .vk-menu-toggle {
    display: block;
  }
  
  .vk-menu-open svg line:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }
  
  .vk-menu-open svg line:nth-child(2) {
    opacity: 0;
  }
  
  .vk-menu-open svg line:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
  }
}

/* ==========================================================================
   6. HERO SECTION
   ========================================================================== */

.vk-hero {
  padding: var(--vk-space-24) 0;
  background: var(--vk-background);
}

.vk-hero-content {
  max-width: 800px;
}

.vk-hero h1 {
  font-size: clamp(32px, 5vw, 56px);
  line-height: 1.1;
  margin-bottom: var(--vk-space-6);
}

.vk-hero-subtitle {
  font-size: var(--vk-text-h4);
  color: var(--vk-secondary);
  margin-bottom: var(--vk-space-8);
}

.vk-hero-metrics {
  display: flex;
  gap: var(--vk-space-12);
  margin-top: var(--vk-space-12);
  padding-top: var(--vk-space-12);
  border-top: var(--vk-border-width) solid var(--vk-primary);
}

.vk-metric {
  text-align: left;
}

.vk-metric-value {
  font-family: var(--vk-font-header);
  font-size: var(--vk-text-h2);
  font-weight: 700;
  line-height: 1;
  margin-bottom: var(--vk-space-2);
}

.vk-metric-label {
  font-size: var(--vk-text-caption);
  color: var(--vk-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ==========================================================================
   7. CARDS
   1px solid black borders only. No fills. No rounded containers.
   ========================================================================== */

.vk-card {
  border: var(--vk-border-width) solid var(--vk-primary);
  padding: var(--vk-space-6);
  background: var(--vk-background);
  transition: background var(--vk-transition);
}

.vk-card:hover {
  background: rgba(26, 26, 46, 0.02);
}

a.vk-card {
  display: block;
  border-bottom: none;
}

a.vk-card:hover {
  border-bottom: none;
}

.vk-card h4 {
  margin-bottom: var(--vk-space-3);
}

.vk-card p {
  color: var(--vk-secondary);
  margin-bottom: 0;
}

/* ==========================================================================
   8. BUTTONS
   ========================================================================== */

.vk-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--vk-space-2);
  padding: var(--vk-space-3) var(--vk-space-6);
  font-family: var(--vk-font-header);
  font-size: var(--vk-text-small);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border: var(--vk-border-width) solid var(--vk-primary);
  cursor: pointer;
  transition: all var(--vk-transition);
  text-decoration: none;
  border-bottom: var(--vk-border-width) solid var(--vk-primary);
}

a.vk-btn {
  border-bottom: var(--vk-border-width) solid var(--vk-primary);
}

a.vk-btn:hover {
  border-bottom: var(--vk-border-width) solid var(--vk-primary);
}

.vk-btn-primary {
  background: var(--vk-primary);
  color: var(--vk-background);
}

.vk-btn-primary:hover {
  background: var(--vk-secondary);
  border-color: var(--vk-secondary);
}

.vk-btn-secondary {
  background: var(--vk-background);
  color: var(--vk-primary);
}

.vk-btn-secondary:hover {
  background: var(--vk-primary);
  color: var(--vk-background);
}

.vk-btn-outline-light {
  background: transparent;
  color: var(--vk-background);
  border-color: var(--vk-background);
}

.vk-btn-outline-light:hover {
  background: var(--vk-background);
  color: var(--vk-primary);
}

.vk-btn-group {
  display: flex;
  gap: var(--vk-space-4);
}

/* ==========================================================================
   9. BADGES
   ========================================================================== */

.vk-badge {
  display: inline-block;
  padding: var(--vk-space-1) var(--vk-space-3);
  font-family: var(--vk-font-header);
  font-size: var(--vk-text-small);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: var(--vk-primary);
  color: var(--vk-background);
}

.vk-badge-secondary {
  background: var(--vk-secondary);
}

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

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

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

.vk-badge-info {
  background: var(--vk-info);
}

.vk-badge-outline {
  background: transparent;
  color: var(--vk-primary);
  border: var(--vk-border-width) solid currentColor;
}

/* ==========================================================================
   10. TABLES
   Secondary dark-navy borders only
   ========================================================================== */

.vk-table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--vk-space-6);
}

.vk-table th,
.vk-table td {
  padding: var(--vk-space-3) var(--vk-space-4);
  text-align: left;
  border: var(--vk-border-width) solid var(--vk-secondary);
}

.vk-table th {
  font-family: var(--vk-font-header);
  font-size: var(--vk-text-small);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: var(--vk-secondary);
  color: var(--vk-background);
}

.vk-table td {
  font-size: var(--vk-text-caption);
}

/* ==========================================================================
   11. FOOTER
   ========================================================================== */

.vk-footer {
  background: var(--vk-secondary);
  color: var(--vk-background);
  padding: var(--vk-space-16) 0 var(--vk-space-8);
}

.vk-footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: var(--vk-space-12);
  margin-bottom: var(--vk-space-12);
}

.vk-footer-brand p {
  color: rgba(255, 255, 255, 0.7);
  margin-top: var(--vk-space-4);
}

.vk-footer-col h4 {
  font-size: var(--vk-text-small);
  margin-bottom: var(--vk-space-4);
  color: var(--vk-background);
}

.vk-footer-links {
  list-style: none;
}

.vk-footer-links li {
  margin-bottom: var(--vk-space-2);
}

.vk-footer-links a {
  color: rgba(255, 255, 255, 0.7);
  font-size: var(--vk-text-caption);
  transition: color var(--vk-transition);
}

.vk-footer-links a:hover {
  color: var(--vk-background);
  border-bottom-color: var(--vk-background);
}

.vk-footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--vk-space-8);
  border-top: var(--vk-border-width) solid rgba(255, 255, 255, 0.2);
  font-size: var(--vk-text-small);
  color: rgba(255, 255, 255, 0.5);
}

.vk-footer .vk-logo {
  margin-bottom: var(--vk-space-2);
}

.vk-footer .vk-logo-mark {
  background: var(--vk-background);
}

/* ==========================================================================
   12. UTILITY CLASSES
   ========================================================================== */

.vk-text-center { text-align: center; }
.vk-text-left { text-align: left; }
.vk-text-right { text-align: right; }

.vk-mb-0 { margin-bottom: 0; }
.vk-mb-2 { margin-bottom: var(--vk-space-2); }
.vk-mb-4 { margin-bottom: var(--vk-space-4); }
.vk-mb-6 { margin-bottom: var(--vk-space-6); }
.vk-mb-8 { margin-bottom: var(--vk-space-8); }
.vk-mb-12 { margin-bottom: var(--vk-space-12); }

.vk-mt-0 { margin-top: 0; }
.vk-mt-4 { margin-top: var(--vk-space-4); }
.vk-mt-6 { margin-top: var(--vk-space-6); }
.vk-mt-8 { margin-top: var(--vk-space-8); }
.vk-mt-12 { margin-top: var(--vk-space-12); }

.vk-py-12 { padding-top: var(--vk-space-12); padding-bottom: var(--vk-space-12); }
.vk-py-24 { padding-top: var(--vk-space-24); padding-bottom: var(--vk-space-24); }

.vk-border-top { border-top: var(--vk-border-width) solid var(--vk-primary); }
.vk-border-bottom { border-bottom: var(--vk-border-width) solid var(--vk-primary); }

.vk-hidden { display: none; }
.vk-sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* ==========================================================================
   13. RESPONSIVE DESIGN
   Mobile collapses to single column, preserves 48px padding
   ========================================================================== */

@media (max-width: 1024px) {
  :root {
    --vk-page-padding: 32px;
  }
  
  .vk-grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .vk-grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .vk-footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --vk-page-padding: 24px;
    --vk-text-h1: 36px;
    --vk-text-h2: 28px;
    --vk-text-h3: 22px;
    --vk-line-h1: 44px;
    --vk-line-h2: 34px;
    --vk-line-h3: 28px;
  }
  
  .vk-nav-menu {
    display: none;
  }
  
  .vk-menu-toggle {
    display: block;
  }
  
  .vk-grid-2,
  .vk-grid-3,
  .vk-grid-4 {
    grid-template-columns: 1fr;
  }
  
  .vk-hero-metrics {
    flex-direction: column;
    gap: var(--vk-space-6);
  }
  
  .vk-footer-grid {
    grid-template-columns: 1fr;
    gap: var(--vk-space-8);
  }
  
  .vk-footer-bottom {
    flex-direction: column;
    gap: var(--vk-space-4);
    text-align: center;
  }
  
  .vk-btn-group {
    flex-direction: column;
  }
}

/* ==========================================================================
   14. PRINT STYLES
   ========================================================================== */

@media print {
  .vk-nav,
  .vk-footer {
    display: none;
  }
  
  body {
    font-size: 12pt;
    line-height: 1.5;
  }
  
  a {
    color: var(--vk-primary);
    text-decoration: underline;
  }
  
  .vk-card {
    break-inside: avoid;
  }
}

/* ==========================================================================
   END OF VALIDKERNEL DESIGN SYSTEM
   Document ID: VK-CSS-2026-001
   INFRASTRUCTURE FIRST. BORING BY DESIGN.
   ========================================================================== */