/* =====================================================
   ELK SOLUTIONS - DARK COCKPIT DESIGN SYSTEM
   Engineering-grade UI for controllable AI products
   ===================================================== */

/* =========================
   DESIGN TOKENS
   ========================= */
:root {
    /* Dark Cockpit Palette */
    --dk-bg-primary: #0a0a0f;
    --dk-bg-secondary: #12121a;
    --dk-bg-card: #16161f;
    --dk-bg-elevated: #1a1a25;
    --dk-bg-hover: #1e1e2a;
    
    /* Borders & Surfaces */
    --dk-border: rgba(255, 255, 255, 0.08);
    --dk-border-subtle: rgba(255, 255, 255, 0.04);
    --dk-border-hover: rgba(255, 255, 255, 0.15);
    
    /* Text Colors */
    --dk-text-primary: #f4f4f5;
    --dk-text-secondary: #a1a1aa;
    --dk-text-muted: #71717a;
    
    /* Accent Colors */
    --dk-accent-primary: #ff6600;
    --dk-accent-primary-hover: #ff7a1a;
    --dk-accent-secondary: #3b82f6;
    --dk-accent-success: #22c55e;
    --dk-accent-warning: #eab308;
    
    /* Gradients & Glows */
    --dk-glow-orange: rgba(255, 102, 0, 0.15);
    --dk-glow-blue: rgba(59, 130, 246, 0.1);
    --dk-gradient-hero: linear-gradient(180deg, #0a0a0f 0%, #12121a 100%);
    --dk-gradient-card: linear-gradient(180deg, var(--dk-bg-card) 0%, var(--dk-bg-secondary) 100%);
    
    /* Typography */
    --font-display: 'Outfit', system-ui, sans-serif;
    --font-body: 'Inter', system-ui, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    
    /* Font Sizes */
    --fs-hero: clamp(2.5rem, 5vw, 4rem);
    --fs-h1: clamp(2rem, 4vw, 3rem);
    --fs-h2: clamp(1.5rem, 3vw, 2rem);
    --fs-h3: clamp(1.125rem, 2vw, 1.375rem);
    --fs-body: 1rem;
    --fs-small: 0.875rem;
    --fs-xs: 0.75rem;
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-full: 9999px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 30px var(--dk-glow-orange);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 400ms ease;
    
    /* Layout */
    --container-max: 1200px;
    --container-narrow: 800px;
}

/* =========================
   RESET & BASE
   ========================= */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body.dark-homepage {
    font-family: var(--font-body);
    font-size: var(--fs-body);
    line-height: 1.6;
    color: var(--dk-text-primary);
    background: var(--dk-bg-primary);
    min-height: 100vh;
}

/* Subtle grid pattern overlay */
body.dark-homepage::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        linear-gradient(rgba(255, 255, 255, 0.02) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
    background-size: 60px 60px;
    pointer-events: none;
    z-index: 0;
}

/* =========================
   TYPOGRAPHY
   ========================= */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 500;
    line-height: 1.2;
    color: var(--dk-text-primary);
}

p {
    color: var(--dk-text-secondary);
    line-height: 1.7;
}

a {
    color: inherit;
    text-decoration: none;
    transition: color var(--transition-fast);
}

/* =========================
   LAYOUT UTILITIES
   ========================= */
.dk-container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--space-xl);
    position: relative;
    z-index: 1;
}

.dk-section {
    padding: var(--space-4xl) 0;
    position: relative;
}

.dk-section-header {
    text-align: center;
    margin-bottom: var(--space-3xl);
}

.dk-section-header h2 {
    font-size: var(--fs-h2);
    margin-bottom: var(--space-md);
}

.dk-section-header p {
    font-size: var(--fs-body);
    max-width: 600px;
    margin: 0 auto;
}

/* Grid layouts */
.dk-grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-xl);
}

.dk-grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-xl);
}

/* =========================
   NAVIGATION
   ========================= */
.dk-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: var(--space-md) 0;
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--dk-border-subtle);
    transition: background var(--transition-base);
}

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

.dk-nav-brand {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-family: var(--font-display);
    font-weight: 500;
    font-size: 1.125rem;
    color: var(--dk-text-primary);
}

.dk-nav-brand img {
    height: 28px;
    width: auto;
}

.dk-nav-brand span {
    color: var(--dk-accent-primary);
}

.dk-nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
}

/* Language switcher (injected by tools/build.js into .lang-switch) */
.lang-switch {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    margin-left: var(--space-md);
    padding: 6px 10px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--dk-border-subtle);
    border-radius: var(--radius-full);
}

.lang-btn {
    font-size: var(--fs-xs);
    font-weight: 600;
    letter-spacing: 0.05em;
    color: var(--dk-text-secondary);
    padding: 4px 8px;
    border-radius: var(--radius-full);
    transition: all var(--transition-fast);
}

.lang-btn:hover {
    color: var(--dk-text-primary);
    background: var(--dk-bg-hover);
}

.lang-btn.active {
    color: var(--dk-text-primary);
    background: rgba(255, 102, 0, 0.12);
    border: 1px solid rgba(255, 102, 0, 0.22);
}

.lang-separator {
    color: var(--dk-text-muted);
    font-size: var(--fs-xs);
    user-select: none;
}

.dk-nav-link {
    font-size: var(--fs-small);
    font-weight: 500;
    color: var(--dk-text-secondary);
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.dk-nav-link:hover {
    color: var(--dk-text-primary);
    background: var(--dk-bg-hover);
}

.dk-nav-cta {
    margin-left: var(--space-md);
}

/* Mobile menu toggle */
.dk-nav-toggle {
    display: none;
    background: none;
    border: none;
    width: 32px;
    height: 32px;
    cursor: pointer;
    position: relative;
}

.dk-nav-toggle span,
.dk-nav-toggle span::before,
.dk-nav-toggle span::after {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--dk-text-primary);
    border-radius: 2px;
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    transition: all var(--transition-fast);
}

.dk-nav-toggle span { top: 50%; transform: translate(-50%, -50%); }
.dk-nav-toggle span::before { content: ''; top: -6px; }
.dk-nav-toggle span::after { content: ''; top: 6px; }

/* =========================
   BUTTONS
   ========================= */
.dk-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    font-family: var(--font-body);
    font-size: var(--fs-small);
    font-weight: 600;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
}

.dk-btn-primary {
    background: var(--dk-accent-primary);
    color: white;
    box-shadow: 0 0 20px rgba(255, 102, 0, 0.3);
}

.dk-btn-primary:hover {
    background: var(--dk-accent-primary-hover);
    box-shadow: 0 0 30px rgba(255, 102, 0, 0.4);
    transform: translateY(-1px);
}

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

.dk-btn-secondary:hover {
    background: var(--dk-bg-hover);
    border-color: var(--dk-border-hover);
}

.dk-btn-ghost {
    background: transparent;
    color: var(--dk-accent-primary);
    padding: var(--space-sm) 0;
}

.dk-btn-ghost:hover {
    color: var(--dk-accent-primary-hover);
}

.dk-btn-ghost::after {
    content: '→';
    margin-left: var(--space-sm);
    transition: transform var(--transition-fast);
}

.dk-btn-ghost:hover::after {
    transform: translateX(4px);
}

/* =========================
   BADGES
   ========================= */
.dk-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-xs) var(--space-md);
    font-size: var(--fs-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-radius: var(--radius-full);
    background: var(--dk-bg-elevated);
    color: var(--dk-text-secondary);
    border: 1px solid var(--dk-border);
}

.dk-badge-flagship {
    background: rgba(255, 102, 0, 0.15);
    color: var(--dk-accent-primary);
    border-color: rgba(255, 102, 0, 0.3);
}

.dk-badge-evidence {
    background: rgba(34, 197, 94, 0.1);
    color: var(--dk-accent-success);
    border-color: rgba(34, 197, 94, 0.2);
}

.dk-badge-guardrails {
    background: rgba(59, 130, 246, 0.1);
    color: var(--dk-accent-secondary);
    border-color: rgba(59, 130, 246, 0.2);
}

.dk-badge-quality {
    background: rgba(234, 179, 8, 0.1);
    color: var(--dk-accent-warning);
    border-color: rgba(234, 179, 8, 0.2);
}

/* =========================
   CARDS
   ========================= */
.dk-card {
    background: var(--dk-bg-card);
    border: 1px solid var(--dk-border);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    transition: all var(--transition-base);
}

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

.dk-card-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: var(--space-lg);
}

.dk-card h3 {
    font-size: var(--fs-h3);
    margin-bottom: var(--space-sm);
}

.dk-card p {
    font-size: var(--fs-small);
    margin-bottom: var(--space-lg);
}

.dk-card ul {
    list-style: none;
    margin-bottom: var(--space-lg);
}

.dk-card li {
    position: relative;
    padding-left: var(--space-lg);
    margin-bottom: var(--space-sm);
    font-size: var(--fs-small);
    color: var(--dk-text-secondary);
}

.dk-card li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--dk-accent-primary);
    font-size: var(--fs-xs);
}

/* Product Tile */
.dk-product-tile {
    position: relative;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.dk-product-tile.flagship {
    border-color: rgba(255, 102, 0, 0.3);
    box-shadow: 0 0 40px rgba(255, 102, 0, 0.1);
}

.dk-product-tile .dk-card-header {
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.dk-product-tile .product-name {
    font-size: var(--fs-h3);
    color: var(--dk-text-primary);
    font-weight: 600;
}

.dk-product-tile .product-promise {
    font-size: var(--fs-small);
    color: var(--dk-text-secondary);
    line-height: 1.6;
}

.dk-product-tile .dk-btn {
    margin-top: auto;
    align-self: flex-start;
}

/* Principle Card */
.dk-principle-card {
    text-align: center;
    padding: var(--space-2xl);
}

.dk-principle-card .icon {
    width: 48px;
    height: 48px;
    margin: 0 auto var(--space-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-lg);
    background: var(--dk-bg-elevated);
    border: 1px solid var(--dk-border);
}

.dk-principle-card .icon svg {
    width: 24px;
    height: 24px;
    stroke: var(--dk-accent-primary);
}

.dk-principle-card h3 {
    font-size: var(--fs-body);
    margin-bottom: var(--space-md);
}

.dk-principle-card p {
    font-size: var(--fs-small);
}

/* =========================
   HERO SECTION
   ========================= */
.dk-hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 80px;
    overflow: hidden;
}

.dk-hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 150%;
    height: 100%;
    background: radial-gradient(ellipse 80% 60% at 50% 20%, var(--dk-glow-orange), transparent 60%);
    pointer-events: none;
}

.dk-hero::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 200px;
    background: linear-gradient(to top, var(--dk-bg-primary), transparent);
    pointer-events: none;
}

.dk-hero-content {
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.dk-hero h1 {
    font-size: var(--fs-hero);
    font-weight: 600;
    margin-bottom: var(--space-lg);
    background: linear-gradient(135deg, var(--dk-text-primary) 0%, var(--dk-accent-primary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.dk-hero .subtitle {
    font-size: clamp(1.125rem, 2vw, 1.375rem);
    color: var(--dk-text-secondary);
    max-width: 700px;
    margin: 0 auto var(--space-2xl);
    line-height: 1.7;
}

.dk-hero-ctas {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-md);
    margin-bottom: var(--space-3xl);
}

.dk-hero-badges {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--space-md);
}

/* =========================
   PRODUCTS SECTION
   ========================= */
.dk-products {
    background: var(--dk-bg-secondary);
    border-top: 1px solid var(--dk-border-subtle);
    border-bottom: 1px solid var(--dk-border-subtle);
}

/* =========================
   PRINCIPLES SECTION
   ========================= */
.dk-principles {
    background: var(--dk-bg-primary);
}

/* =========================
   STUDIO SECTION
   ========================= */
.dk-studio {
    background: var(--dk-bg-secondary);
    border-top: 1px solid var(--dk-border-subtle);
    border-bottom: 1px solid var(--dk-border-subtle);
}

.dk-studio-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-3xl);
    align-items: center;
}

.dk-studio-text h2 {
    font-size: var(--fs-h2);
    margin-bottom: var(--space-lg);
}

.dk-studio-text > p {
    margin-bottom: var(--space-xl);
}

.dk-studio-text ul {
    list-style: none;
    margin-bottom: var(--space-xl);
}

.dk-studio-text li {
    position: relative;
    padding-left: var(--space-lg);
    margin-bottom: var(--space-md);
    color: var(--dk-text-secondary);
}

.dk-studio-text li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--dk-accent-success);
}

.dk-studio-visual {
    background: var(--dk-bg-card);
    border: 1px solid var(--dk-border);
    border-radius: var(--radius-xl);
    padding: var(--space-2xl);
    text-align: center;
}

.dk-studio-visual .icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--space-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-xl);
    background: var(--dk-bg-elevated);
    border: 1px solid var(--dk-border);
    font-size: 2.5rem;
}

/* =========================
   PROOF SECTION
   ========================= */
.dk-proof {
    background: var(--dk-bg-primary);
}

.dk-proof-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-xl);
}

.dk-proof-card {
    background: var(--dk-bg-card);
    border: 1px solid var(--dk-border);
    border-radius: var(--radius-lg);
    padding: var(--space-2xl);
}

.dk-proof-card blockquote {
    font-size: var(--fs-body);
    font-style: italic;
    color: var(--dk-text-secondary);
    margin-bottom: var(--space-lg);
    padding-left: var(--space-lg);
    border-left: 3px solid var(--dk-accent-primary);
}

.dk-proof-card cite {
    display: block;
    font-size: var(--fs-small);
    color: var(--dk-text-muted);
    font-style: normal;
}

.dk-proof-stats {
    display: flex;
    gap: var(--space-xl);
    margin-top: var(--space-lg);
    padding-top: var(--space-lg);
    border-top: 1px solid var(--dk-border);
}

.dk-proof-stat {
    text-align: center;
}

.dk-proof-stat .value {
    display: block;
    font-size: var(--fs-h3);
    font-weight: 600;
    color: var(--dk-accent-primary);
}

.dk-proof-stat .label {
    font-size: var(--fs-xs);
    color: var(--dk-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* =========================
   INSIGHTS SECTION
   ========================= */
.dk-insights {
    background: var(--dk-bg-secondary);
    border-top: 1px solid var(--dk-border-subtle);
}

.dk-insights-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-xl);
}

.dk-insight-card {
    background: var(--dk-bg-card);
    border: 1px solid var(--dk-border);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    transition: all var(--transition-base);
}

.dk-insight-card:hover {
    border-color: var(--dk-border-hover);
    transform: translateY(-2px);
}

.dk-insight-card .meta {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-md);
}

.dk-insight-card .tag {
    font-size: var(--fs-xs);
    color: var(--dk-accent-primary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.dk-insight-card .date {
    font-size: var(--fs-xs);
    color: var(--dk-text-muted);
}

.dk-insight-card h3 {
    font-size: var(--fs-body);
    line-height: 1.4;
    margin-bottom: var(--space-md);
}

/* =========================
   FOOTER
   ========================= */
.dk-footer {
    background: var(--dk-bg-primary);
    border-top: 1px solid var(--dk-border-subtle);
    padding: var(--space-3xl) 0;
}

.dk-footer-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--space-xl);
}

.dk-footer-brand {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-family: var(--font-display);
    font-weight: 500;
    color: var(--dk-text-primary);
}

.dk-footer-brand img {
    height: 24px;
}

.dk-footer-brand span {
    color: var(--dk-accent-primary);
}

.dk-footer-links {
    display: flex;
    align-items: center;
    gap: var(--space-xl);
}

.dk-footer-link {
    font-size: var(--fs-small);
    color: var(--dk-text-muted);
    transition: color var(--transition-fast);
}

.dk-footer-link:hover {
    color: var(--dk-text-primary);
}

.dk-footer-cta {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.dk-footer-bottom {
    margin-top: var(--space-xl);
    padding-top: var(--space-xl);
    border-top: 1px solid var(--dk-border-subtle);
    text-align: center;
}

.dk-footer-bottom p {
    font-size: var(--fs-xs);
    color: var(--dk-text-muted);
}

/* =========================
   RESPONSIVE
   ========================= */
@media (max-width: 1024px) {
    .dk-grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .dk-studio-content {
        grid-template-columns: 1fr;
    }
    
    .dk-proof-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    :root {
        --space-xl: 1.5rem;
        --space-2xl: 2rem;
        --space-3xl: 3rem;
        --space-4xl: 4rem;
    }
    
    .dk-container {
        padding: 0 var(--space-md);
    }
    
    .dk-nav-links {
        display: none;
    }
    
    .dk-nav-toggle {
        display: block;
    }
    
    .dk-nav.open .dk-nav-links {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--dk-bg-secondary);
        border-bottom: 1px solid var(--dk-border);
        padding: var(--space-lg);
    }
    
    .dk-grid-2,
    .dk-grid-3 {
        grid-template-columns: 1fr;
    }
    
    .dk-hero h1 {
        font-size: clamp(2rem, 8vw, 3rem);
    }
    
    .dk-hero-ctas {
        flex-direction: column;
    }
    
    .dk-hero-badges {
        flex-direction: column;
    }
    
    .dk-insights-grid {
        grid-template-columns: 1fr;
    }
    
    .dk-footer-inner {
        flex-direction: column;
        text-align: center;
    }
    
    .dk-footer-links {
        flex-wrap: wrap;
        justify-content: center;
    }
}

/* =========================
   ACCESSIBILITY
   ========================= */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

.dk-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;
}

/* Focus states */
:focus-visible {
    outline: 2px solid var(--dk-accent-primary);
    outline-offset: 2px;
}

.dk-btn:focus-visible {
    box-shadow: 0 0 0 4px rgba(255, 102, 0, 0.3);
}