/* ========================================
   CSS Variables (Light & Dark Themes)
   ======================================== */
:root {
    /* Light Theme Colors */
    --color-bg-primary: #ffffff;
    --color-bg-secondary: #f8f9fa;
    --color-bg-tertiary: #f1f3f4;
    --color-bg-card: #ffffff;
    --color-text-primary: #1a1a2e;
    --color-text-secondary: #4a4a68;
    --color-text-muted: #6b6b80;
    --color-accent: #4361ee;
    --color-accent-hover: #3451d9;
    --color-accent-light: rgba(67, 97, 238, 0.1);
    --color-border: #e2e4e8;
    --color-border-light: #f0f2f4;
    --color-success: #10b981;
    --color-error: #ef4444;
    --color-warning: #f59e0b;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -2px rgba(0, 0, 0, 0.04);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #4361ee 0%, #7c3aed 100%);
    --gradient-hero: linear-gradient(135deg, #f8f9ff 0%, #f0f4ff 100%);
    --gradient-card: linear-gradient(180deg, #ffffff 0%, #f8f9fa 100%);

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
    
    /* Layout */
    --container-max: 1200px;
    --header-height: 72px;
}

/* Dark Theme */
[data-theme="dark"] {
    --color-bg-primary: #0f0f1a;
    --color-bg-secondary: #1a1a2e;
    --color-bg-tertiary: #252542;
    --color-bg-card: #1e1e32;
    --color-text-primary: #f1f5f9;
    --color-text-secondary: #cbd5e1;
    --color-text-muted: #94a3b8;
    --color-accent: #6366f1;
    --color-accent-hover: #818cf8;
    --color-accent-light: rgba(99, 102, 241, 0.15);
    --color-border: #2e2e4a;
    --color-border-light: #252540;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 10px 10px -5px rgba(0, 0, 0, 0.4);
    
    --gradient-hero: linear-gradient(135deg, #0f0f1a 0%, #1a1a2e 100%);
    --gradient-card: linear-gradient(180deg, #1e1e32 0%, #1a1a2e 100%);
}

/* ========================================
   Base Styles
   ======================================== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-text-primary);
    background-color: var(--color-bg-primary);
    transition: background-color var(--transition-base), color var(--transition-base);
    overflow-x: hidden;
}

.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

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

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

ul {
    list-style: none;
}

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

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

input, textarea {
    font-family: inherit;
    font-size: 1rem;
}

/* ========================================
   Typography
   ======================================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    color: var(--color-text-primary);
}

h1 { font-size: clamp(2.5rem, 5vw, 4rem); }
h2 { font-size: clamp(2rem, 4vw, 2.75rem); }
h3 { font-size: clamp(1.25rem, 2vw, 1.5rem); }
h4 { font-size: 1.125rem; }

/* ========================================
   Header & Navigation
   ======================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: var(--color-bg-primary);
    border-bottom: 1px solid var(--color-border-light);
    z-index: 1000;
    transition: all var(--transition-base);
}

.header.scrolled {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-md);
}

[data-theme="dark"] .header.scrolled {
    background: rgba(15, 15, 26, 0.95);
}

.nav {
    height: 100%;
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text-primary);
}

.logo-icon {
    display: flex;
    align-items: center;
    color: var(--color-accent);
    font-size: 1.75rem;
}

.logo-icon img {
    max-height: 40px;
    border-radius: 8px;
}

.logo-icon .logo-dark {
    display: block;
}

.logo-icon .logo-light {
    display: none;
}

[data-theme="dark"] .logo-icon .logo-dark {
    display: none;
}

[data-theme="dark"] .logo-icon .logo-light {
    display: block;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
}

.nav-link {
    position: relative;
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    padding: var(--spacing-xs) 0;
    transition: color var(--transition-fast);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-accent);
    transition: width var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-accent);
}

.nav-link.active::after,
.nav-link:hover::after {
    width: 100%;
}

.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    color: var(--color-text-secondary);
    background: var(--color-bg-tertiary);
    transition: all var(--transition-fast);
}

.theme-toggle:hover {
    color: var(--color-accent);
    background: var(--color-accent-light);
}

.theme-toggle .icon-moon {
    display: none;
}

[data-theme="dark"] .theme-toggle .icon-sun {
    display: none;
}

[data-theme="dark"] .theme-toggle .icon-moon {
    display: block;
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 32px;
    height: 32px;
    padding: 4px;
}

.mobile-toggle span {
    display: block;
    width: 100%;
    height: 2px;
    background: var(--color-text-primary);
    border-radius: var(--radius-full);
    transition: all var(--transition-fast);
}

.mobile-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.mobile-toggle.active span:nth-child(2) {
    opacity: 0;
}

.mobile-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ========================================
   Buttons
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: 0.875rem 1.75rem;
    font-size: 0.9375rem;
    font-weight: 600;
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
    cursor: pointer;
    text-decoration: none;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-md), 0 4px 14px rgba(67, 97, 238, 0.25);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), 0 8px 20px rgba(67, 97, 238, 0.35);
    color: white;
}

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

.btn-secondary:hover {
    background: var(--color-accent-light);
    border-color: var(--color-accent);
    color: var(--color-accent);
}

.btn-full {
    width: 100%;
}

.btn .btn-loader {
    display: none;
    width: 18px;
    height: 18px;
    border: 2px solid transparent;
    border-top-color: currentColor;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

.btn.loading .btn-text {
    visibility: hidden;
}

.btn.loading .btn-loader {
    position: absolute;
    display: block;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: calc(var(--header-height) + var(--spacing-3xl)) var var(--spacing-3xl);
    overflow(--spacing-lg): hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background: var(--gradient-hero);
    z-index: -2;
}

.hero-bg::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 80%;
    height: 150%;
    background: radial-gradient(ellipse, var(--color-accent-light) 0%, transparent 70%);
    animation: heroGlow 15s ease-in-out infinite;
}

@keyframes heroGlow {
    0%, 100% { transform: translate(0, 0) scale(1); opacity: 0.5; }
    50% { transform: translate(-10%, 10%) scale(1.1); opacity: 0.8; }
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.hero-badge {
    display: inline-block;
    padding: 0.5rem 1rem;
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--color-accent);
    background: var(--color-accent-light);
    border-radius: var(--radius-full);
    margin-bottom: var(--spacing-lg);
    animation: fadeInUp 0.6s ease-out;
}

.hero-title {
    font-size: clamp(2.25rem, 5vw, 3.5rem);
    font-weight: 700;
    line-height: 1.15;
    margin-bottom: var(--spacing-lg);
    animation: fadeInUp 0.6s ease-out 0.1s backwards;
}

.hero-highlight {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.125rem;
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto var(--spacing-xl);
    animation: fadeInUp 0.6s ease-out 0.2s backwards;
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    margin-bottom: var(--spacing-2xl);
    animation: fadeInUp 0.6s ease-out 0.3s backwards;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-2xl);
    flex-wrap: wrap;
    animation: fadeInUp 0.6s ease-out 0.4s backwards;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-text-primary);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ========================================
   Section Styles
   ======================================== */
section {
    padding: var(--spacing-3xl) 0;
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto var(--spacing-2xl);
}

.section-tag {
    display: inline-block;
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--color-accent);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--spacing-sm);
}

.section-title {
    margin-bottom: var(--spacing-md);
}

.section-subtitle {
    font-size: 1.0625rem;
    color: var(--color-text-secondary);
}

/* ========================================
   Services Section
   ======================================== */
.services {
    background: var(--color-bg-secondary);
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-lg);
}

.service-card {
    position: relative;
    background: var(--gradient-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    transition: all var(--transition-base);
    overflow: hidden;
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform var(--transition-base);
}

.service-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
    border-color: transparent;
}

.service-card:hover::before {
    transform: scaleX(1);
}

.service-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 56px;
    height: 56px;
    background: var(--color-accent-light);
    color: var(--color-accent);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-md);
}

.service-title {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.service-description {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
}

.service-features {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.service-features li {
    position: relative;
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--color-text-muted);
    padding-left: var(--spacing-md);
}

.service-features li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--color-accent);
}

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

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    align-items: center;
}

.about-content .section-title {
    text-align: left;
}

.about-text {
    font-size: 1rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
}

.about-features {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-lg);
}

.about-feature {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
}

.about-feature-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    font-size: 0.75rem;
    color: var(--color-success);
    background: rgba(16, 185, 129, 0.1);
    border-radius: var(--radius-full);
}

.about-visual {
    position: relative;
}

.about-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.about-card-header {
    display: flex;
    gap: 6px;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-bg-tertiary);
    border-bottom: 1px solid var(--color-border);
}

.about-card-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--color-border);
}

.about-card-dot:nth-child(1) { background: #ef4444; }
.about-card-dot:nth-child(2) { background: #f59e0b; }
.about-card-dot:nth-child(3) { background: #10b981; }

.about-card-content {
    padding: var(--spacing-lg);
}

.code-block {
    font-family: 'Fira Code', 'Monaco', monospace;
    font-size: 0.875rem;
    line-height: 1.8;
}

.code-keyword { color: #c792ea; }
.code-class { color: #ffcb6b; }
.code-function { color: #82aaff; }
.code-string { color: #c3e88d; }
.code-bracket { color: #89ddff; }

.about-decoration {
    position: absolute;
    top: -20px;
    right: -20px;
    width: 150px;
    height: 150px;
    background: var(--color-accent-light);
    border-radius: var(--radius-full);
    z-index: -1;
    filter: blur(40px);
}

/* ========================================
   Contact Section
   ======================================== */
.contact {
    background: var(--color-bg-secondary);
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: var(--spacing-2xl);
    align-items: start;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.contact-item {
    display: flex;
    gap: var(--spacing-md);
}

.contact-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: var(--color-accent-light);
    color: var(--color-accent);
    border-radius: var(--radius-lg);
    flex-shrink: 0;
}

.contact-item h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.contact-item p {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
}

.contact-form {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
}

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

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-xs);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.875rem 1rem;
    font-size: 0.9375rem;
    color: var(--color-text-primary);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px var(--color-accent-light);
}

.form-group input.error,
.form-group textarea.error {
    border-color: var(--color-error);
}

.form-group input.error:focus,
.form-group textarea.error:focus {
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.1);
}

.error-message {
    display: block;
    font-size: 0.8125rem;
    color: var(--color-error);
    margin-top: 0.25rem;
    min-height: 1.25rem;
}

.form-status {
    margin-top: var(--spacing-md);
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.9375rem;
    font-weight: 500;
    border-radius: var(--radius-md);
    text-align: center;
    opacity: 0;
    transform: translateY(-10px);
    transition: all var(--transition-base);
}

.form-status.show {
    opacity: 1;
    transform: translateY(0);
}

.form-status.success {
    background: rgba(16, 185, 129, 0.1);
    color: var(--color-success);
}

.form-status.error {
    background: rgba(239, 68, 68, 0.1);
    color: var(--color-error);
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background: var(--color-bg-primary);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    gap: var(--spacing-2xl);
    margin-bottom: var(--spacing-xl);
}

.footer-brand {
    max-width: 300px;
}

.footer-brand .logo {
    margin-bottom: var(--spacing-sm);
}

.footer-brand p {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
}

.footer-links {
    display: flex;
    gap: var(--spacing-3xl);
}

.footer-column h4 {
    font-size: 0.9375rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.footer-column ul {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.footer-column a {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
    transition: color var(--transition-fast);
}

.footer-column a:hover {
    color: var(--color-accent);
}

.footer-bottom {
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border-light);
    text-align: center;
}

.footer-bottom p {
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 1024px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }
    
    .about-visual {
        order: -1;
        max-width: 500px;
        margin: 0 auto;
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }
    
    .contact-info {
        flex-direction: row;
        flex-wrap: wrap;
    }
    
    .contact-item {
        flex: 1;
        min-width: 200px;
    }
}

@media (max-width: 768px) {
    :root {
        --header-height: 64px;
    }
    
    .mobile-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        flex-direction: column;
        background: var(--color-bg-primary);
        border-bottom: 1px solid var(--color-border);
        padding: var(--spacing-lg);
        gap: var(--spacing-md);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-base);
    }
    
    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .theme-toggle {
        position: absolute;
        right: 80px;
    }
    
    .hero-stats {
        gap: var(--spacing-lg);
    }
    
    .stat-number {
        font-size: 1.5rem;
    }
    
    .services-grid {
        grid-template-columns: 1fr;
    }
    
    .about-features {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-brand {
        max-width: 100%;
    }
    
    .footer-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    section {
        padding: var(--spacing-2xl) 0;
    }
    
    .hero-actions {
        flex-direction: column;
    }
    
    .hero-actions .btn {
        width: 100%;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: var(--spacing-md);
    }
    
    .contact-item {
        min-width: 100%;
    }
    
    .footer-links {
        flex-direction: column;
        gap: var(--spacing-lg);
    }
}

/* ========================================
   Utility Classes
   ======================================== */
.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;
}