/* ============================================
   NEXUS - Modern Interactive Website Stylesheet
   ============================================ */

/* CSS Custom Properties (Design Tokens) */
:root {
    /* Colors - Light Mode */
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --secondary: #8b5cf6;
    --accent: #ec4899;
    
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #e2e8f0;
    
    --surface: #ffffff;
    --border: #e2e8f0;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -1px rgb(0 0 0 / 0.06);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -2px rgb(0 0 0 / 0.05);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -4px rgb(0 0 0 / 0.01);
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-xxl: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition: 300ms ease;
    --transition-slow: 500ms ease;
}

/* Dark Mode Colors */
[data-theme="dark"] {
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    
    --surface: #1e293b;
    --border: #334155;
}

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

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Oxygen, Ubuntu, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color var(--transition), color var(--transition);
}

/* Selection */
::selection {
    background: var(--primary);
    color: white;
}

/* ============================================
   Typography
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    margin: 0;
    font-weight: 700;
    line-height: 1.2;
}

.gradient-text {
    background: linear-gradient(135deg, var(--primary), var(--secondary), var(--accent));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    display: inline-block;
}

/* ============================================
   Navigation Bar
   ============================================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--bg-primary);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border);
}

.navbar .nav-brand {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary);
    padding: var(--spacing-md) var(--spacing-xl);
    display: inline-block;
}

.nav-links {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    gap: var(--spacing-lg);
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    transition: all var(--transition);
}

.nav-links a:hover {
    color: var(--primary);
    background: var(--bg-secondary);
}

.nav-links a.active {
    color: var(--primary);
    background: var(--bg-secondary);
}

/* ============================================
   Dark Mode Toggle Button
   ============================================ */
#theme-toggle {
    position: fixed;
    top: 100px;
    right: var(--spacing-xl);
    z-index: 999;
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--text-primary);
    cursor: pointer;
    padding: var(--spacing-sm);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
}

#theme-toggle:hover {
    background: var(--bg-secondary);
    transform: scale(1.1);
}

#theme-toggle svg {
    width: 20px;
    height: 20px;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    min-height: 100vh;
    display: grid;
    grid-template-columns: 1fr 1fr;
    padding-top: calc(80px + var(--spacing-xxl));
    overflow: hidden;
}

.hero-content {
    padding: var(--spacing-xxl);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.hero h1 {
    font-size: clamp(2.5rem, 8vw, 4.5rem);
    margin-bottom: var(--spacing-md);
}

.gradient-text {
    background: linear-gradient(135deg, #6366f1, #ec4899, #8b5cf6);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.subtext {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    max-width: 480px;
}

.btn-primary {
    display: inline-block;
    padding: var(--spacing-md) var(--spacing-xxl);
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: all var(--transition);
    box-shadow: var(--shadow-md);
}

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

.hero-visual {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

#hero-canvas {
    width: 100%;
    height: 100%;
    min-height: 400px;
}

/* ============================================
   Features Section
   ============================================ */
.section {
    padding: var(--spacing-xxl);
}

.section-title {
    font-size: clamp(1.75rem, 5vw, 2.5rem);
    margin-bottom: var(--spacing-xl);
    text-align: center;
}

.features-section {
    background: var(--bg-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-xl);
    max-width: 1200px;
    margin: 0 auto;
}

.feature-card {
    background: var(--surface);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition);
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

.feature-card h3 {
    color: var(--primary);
    margin-bottom: var(--spacing-sm);
}

/* ============================================
   Demo Section (Live Search)
   ============================================ */
.demo-section {
    background: linear-gradient(135deg, var(--bg-secondary), var(--surface));
}

.demo-container {
    max-width: 900px;
    margin: 0 auto;
}

.search-box {
    position: relative;
    margin-bottom: var(--spacing-xl);
}

#search-input {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-xxl);
    font-size: 1.125rem;
    border: 2px solid var(--border);
    background: var(--surface);
    color: var(--text-primary);
    transition: all var(--transition);
}

#search-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
}

.search-icon {
    position: absolute;
    right: var(--spacing-md);
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.25rem;
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-md);
    padding-top: var(--spacing-md);
}

.demo-item {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition);
}

.demo-item:hover {
    transform: translateX(4px);
}

.demo-item h4 {
    margin-bottom: var(--spacing-xs);
}

.demo-item p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* ============================================
   About Section
   ============================================ */
.about-section {
    background: var(--bg-secondary);
}

.about-text {
    max-width: 700px;
    margin: 0 auto;
    font-size: 1.25rem;
    color: var(--text-secondary);
    text-align: center;
}

/* ============================================
   Contact Section & Form
   ============================================ */
.contact-section {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
}

.contact-form {
    max-width: 500px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: var(--spacing-md);
}

.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: white;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-md);
    background: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: white;
    font-size: 1rem;
    border-radius: var(--radius-md);
    transition: all var(--transition);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: rgba(255, 255, 255, 0.7);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    background: rgba(255, 255, 255, 0.25);
    border-color: white;
}

.btn-full {
    width: 100%;
    margin-top: var(--spacing-lg);
}

/* ============================================
   Footer
   ============================================ */
.footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--border);
}

.footer-content {
    max-width: 800px;
    margin: var(--spacing-xl) auto;
    text-align: center;
}

.footer-nav a {
    color: var(--text-secondary);
    text-decoration: none;
}

.footer-nav a:hover {
    color: var(--primary);
}

/* ============================================
   Modal & Overlay
   ============================================ */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1001;
}

.modal-overlay.hidden {
    display: none;
}

.modal-content {
    background: var(--surface);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    max-width: 400px;
    text-align: center;
    box-shadow: var(--shadow-xl);
}

.modal-content h3 {
    color: var(--primary);
    margin-bottom: var(--spacing-sm);
}

.btn-secondary {
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-lg);
    cursor: pointer;
    margin-top: var(--spacing-md);
}

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

/* ============================================
   Success Message
   ============================================ */
#success-message {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    background: #10b981;
    color: white;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    box-shadow: var(--shadow-lg);
    z-index: 1002;
}

#success-message svg {
    width: 24px;
    height: 24px;
}

/* ============================================
   Hidden Utility Class
   ============================================ */
.hidden {
    display: none !important;
}

/* ============================================
   Animations
   ============================================ */
@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

.hero-visual::before {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.3), transparent);
    filter: blur(60px);
    animation: pulse 3s ease-in-out infinite;
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 992px) {
    .hero {
        grid-template-columns: 1fr;
        padding-top: var(--spacing-xxl);
    }
    
    .hero-content {
        padding: var(--spacing-xl);
    }
    
    .hero-visual {
        min-height: 300px;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .features-grid,
    .demo-container,
    .about-text {
        padding: var(--spacing-md);
    }
    
    .hero h1 {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-xxl: 2rem;
    }
    
    .feature-card,
    .demo-item {
        padding: var(--spacing-md);
    }
    
    .btn-primary {
        width: 100%;
    }
}

/* ============================================
   Print Styles
   ============================================ */
@media print {
    .navbar,
    #theme-toggle,
    .hero-visual,
    .footer-nav {
        display: none;
    }
    
    body {
        background: white;
        color: black;
    }
}