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

:root {
    /* Light mode colors */
    --color-primary: #2563eb;
    --color-primary-hover: #1d4ed8;
    --color-secondary: #64748b;
    --color-background: #ffffff;
    --color-surface: #f8fafc;
    --color-text: #0f172a;
    --color-text-secondary: #475569;
    --color-border: #e2e8f0;
    --color-shadow: rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-size-base: 16px;
    --line-height: 1.6;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Border radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    
    /* Transitions */
    --transition: all 0.3s ease;
    
    /* Container width */
    --container-max-width: 1200px;
}

[data-theme="dark"] {
    /* Dark mode colors */
    --color-primary: #3b82f6;
    --color-primary-hover: #2563eb;
    --color-secondary: #94a3b8;
    --color-background: #0f172a;
    --color-surface: #1e293b;
    --color-text: #f1f5f9;
    --color-text-secondary: #cbd5e1;
    --color-border: #334155;
    --color-shadow: rgba(0, 0, 0, 0.3);
}

html {
    font-size: var(--font-size-base);
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    line-height: var(--line-height);
    color: var(--color-text);
    background-color: var(--color-background);
    transition: background-color 0.3s ease, color 0.3s ease;
    overflow-x: hidden;
}

/* ===========================
   Container
   =========================== */
.container {
    width: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ===========================
   Header & Navigation
   =========================== */
.header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: var(--color-background);
    border-bottom: 1px solid var(--color-border);
    backdrop-filter: blur(10px);
    transition: var(--transition);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-sm) 0;
}

.nav-brand .logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-primary);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
    align-items: center;
}

.nav-link {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s ease;
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-primary);
    transition: width 0.3s ease;
}

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

.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
    background-color: var(--color-surface);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

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

.theme-icon::before {
    content: '☀️';
    font-size: 1.2rem;
}

[data-theme="dark"] .theme-icon::before {
    content: '🌙';
}

.menu-toggle {
    display: none;
    width: 40px;
    height: 40px;
    border: none;
    background: transparent;
    cursor: pointer;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
}

.hamburger::before,
.hamburger,
.hamburger::after {
    content: '';
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-text);
    transition: var(--transition);
}

/* ===========================
   Hero Section
   =========================== */
.hero {
    padding: var(--spacing-2xl) 0;
    min-height: 70vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-background) 100%);
}

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

.hero-title {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 800;
    margin-bottom: var(--spacing-md);
    line-height: 1.2;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: clamp(1rem, 3vw, 1.5rem);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xl);
}

.hero-cta {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* ===========================
   Buttons
   =========================== */
.btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    font-size: 1rem;
    text-align: center;
}

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

.btn-primary:hover {
    background-color: var(--color-primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 10px 20px var(--color-shadow);
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-text);
    border: 2px solid var(--color-border);
}

.btn-secondary:hover {
    background-color: var(--color-surface);
    transform: translateY(-2px);
}

/* ===========================
   Sections
   =========================== */
.section {
    padding: var(--spacing-2xl) 0;
}

.section-alt {
    background-color: var(--color-surface);
}

.section-title {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

/* ===========================
   Grid & Cards
   =========================== */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.card {
    background-color: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    transition: var(--transition);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px var(--color-shadow);
}

.card-icon {
    width: 64px;
    height: 64px;
    border-radius: var(--radius-md);
    background-color: var(--color-surface);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
    color: var(--color-primary);
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.card-text {
    color: var(--color-text-secondary);
    line-height: 1.6;
}

/* ===========================
   Products
   =========================== */
.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.product-card {
    background-color: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    transition: var(--transition);
}

.product-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px var(--color-shadow);
}

.product-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.product-description {
    color: var(--color-text-secondary);
}

/* ===========================
   Contact
   =========================== */
.contact-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

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

.contact-text {
    color: var(--color-text-secondary);
    line-height: 1.6;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--color-text-secondary);
}

.contact-item svg {
    color: var(--color-primary);
    flex-shrink: 0;
}

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

.form-group {
    display: flex;
    flex-direction: column;
}

.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 0.875rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background-color: var(--color-background);
    color: var(--color-text);
    font-family: var(--font-sans);
    font-size: 1rem;
    transition: var(--transition);
}

.contact-form input:focus,
.contact-form textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.contact-form textarea {
    resize: vertical;
    min-height: 120px;
}

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

.footer-text {
    text-align: center;
    color: var(--color-text-secondary);
}

/* ===========================
   Responsive Design (Mobile First)
   =========================== */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 73px;
        left: 0;
        right: 0;
        flex-direction: column;
        background-color: var(--color-background);
        border-bottom: 1px solid var(--color-border);
        padding: var(--spacing-md);
        gap: var(--spacing-sm);
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: var(--transition);
    }
    
    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: all;
    }
    
    .menu-toggle {
        display: flex;
    }
    
    .hero {
        padding: var(--spacing-xl) 0;
        min-height: 60vh;
    }
    
    .hero-cta {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
    }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .container {
        padding: 0 var(--spacing-lg);
    }
}