/* CSS Variables & Design System */
:root {
    --color-primary: #0056b3; /* Scientific Blue */
    --color-primary-dark: #004494;
    --color-secondary: #00a8cc; /* Teal/Cyan accents */
    --color-accent: #f0f7ff; /* Light blue background */
    --color-text-main: #1a1a1a;
    --color-text-muted: #666666;
    --color-background: #ffffff;
    --color-surface: #f8f9fa;
    --color-border: #e0e0e0;
    
    --font-family: 'Inter', system-ui, -apple-system, sans-serif;
    
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 16px;
    
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
}

/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    color: var(--color-text-main);
    line-height: 1.6;
    background-color: var(--color-background);
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.2s;
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    display: block;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

/* Typography */
h1, h2, h3, h4 {
    line-height: 1.2;
    font-weight: 700;
    color: var(--color-text-main);
}

h1 { font-size: 3.5rem; }
h2 { font-size: 2.5rem; margin-bottom: var(--spacing-sm); }
h3 { font-size: 1.5rem; margin-bottom: var(--spacing-xs); }

p {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-muted);
}

/* Utilities */
.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto var(--spacing-lg);
}

.placeholder {
    background-color: var(--color-surface);
    border: 2px dashed var(--color-border);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-muted);
    font-weight: 500;
    padding: var(--spacing-md);
    position: relative;
    overflow: hidden;
}

.placeholder::after {
    content: attr(data-label);
    text-align: center;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.8rem 1.6rem;
    border-radius: var(--border-radius-sm);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
}

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

.btn-primary:hover {
    background-color: var(--color-primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

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

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

.full-width {
    width: 100%;
}

/* Header */
.header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-sm) 0;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--color-text-main);
    letter-spacing: -0.5px;
}

.logo-accent {
    color: var(--color-primary);
}

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

.nav-link {
    font-weight: 500;
    color: var(--color-text-muted);
}

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

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    flex-direction: column;
    gap: 5px;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: var(--color-text-main);
    transition: 0.3s;
}

/* Hero Section */
.hero {
    padding: var(--spacing-xl) 0;
    background: linear-gradient(135deg, #fdfbfb 0%, #ebedee 100%);
    background: var(--color-accent);
}

.hero-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
    align-items: center;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-md);
    max-width: 90%;
}

.hero-actions {
    display: flex;
    gap: var(--spacing-sm);
}

.hero-image-placeholder {
    height: 400px;
    border-radius: var(--border-radius-lg);
    background-color: white;
    box-shadow: var(--shadow-lg);
    border: none;
}

/* About Section */
.about {
    padding: var(--spacing-xl) 0;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.feature-card {
    padding: var(--spacing-md);
    background: white;
    border-radius: var(--border-radius-md);
    border: 1px solid var(--color-border);
    transition: transform 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--color-primary);
    box-shadow: var(--shadow-md);
}

.placeholder-icon {
    width: 48px;
    height: 48px;
    background-color: var(--color-accent);
    border-radius: 50%;
    margin-bottom: var(--spacing-sm);
}

/* Products Section */
.products {
    padding: var(--spacing-xl) 0;
    background-color: var(--color-surface);
}

.category-title {
    margin: var(--spacing-lg) 0 var(--spacing-md);
    padding-bottom: var(--spacing-xs);
    border-bottom: 2px solid var(--color-border);
    display: inline-block;
}

.product-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-md);
}

.product-card {
    background: white;
    border-radius: var(--border-radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: box-shadow 0.3s;
}

.product-card:hover {
    box-shadow: var(--shadow-md);
}

.product-image {
    height: 200px;
    width: 100%;
    border-bottom: 1px solid var(--color-border);
}

.product-info {
    padding: var(--spacing-md);
}

.product-info h4 {
    margin-bottom: 0.5rem;
    color: var(--color-primary);
}

/* Contact Section */
.contact {
    padding: var(--spacing-xl) 0;
    background-color: white;
}

.contact-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
}

.contact-details li {
    margin-bottom: var(--spacing-sm);
    display: flex;
    flex-direction: column;
}

.contact-details .label {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

.contact-form {
    padding: var(--spacing-md);
    background-color: var(--color-surface);
    border-radius: var(--border-radius-md);
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-sm);
    font-family: inherit;
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(0, 86, 179, 0.1);
}

/* Footer */
.footer {
    background-color: #111;
    color: #eee;
    padding: var(--spacing-lg) 0;
}

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

.footer .logo {
    color: white;
}

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

.footer-links a {
    color: #999;
}

.footer-links a:hover {
    color: white;
}

/* Responsive Design */
@media (max-width: 768px) {
    h1 { font-size: 2.5rem; }
    
    .nav-list {
        display: none; /* Hide for now, can implement toggle later */
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: var(--spacing-md);
        box-shadow: var(--shadow-md);
        border-bottom: 1px solid var(--color-border);
    }

    .nav-list.active {
        display: flex;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .hero-container,
    .contact-container {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
        text-align: center;
    }

    .hero-image-placeholder {
        order: -1; /* Image on top on mobile */
        height: 250px;
    }

    .hero-actions {
        justify-content: center;
    }
    
    .section-header {
        text-align: center;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}