/* ===========================
   CSS Reset & Base Styles
   =========================== */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Palette */
    --primary-blue: #2563eb;
    --primary-purple: #7c3aed;
    --gradient-start: #3b82f6;
    --gradient-end: #8b5cf6;
    
    --dark-bg: #0f172a;
    --dark-card: #1e293b;
    --light-bg: #f8fafc;
    --white: #ffffff;
    
    --text-primary: #1e293b;
    --text-secondary: #475569;
    --text-light: #64748b;
    --text-white: #f8fafc;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.2);
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

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

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

/* ===========================
   Typography
   =========================== */

h1, h2, h3, h4, h5, h6 {
    line-height: 1.2;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

h1 sub, h2 sub, h3 sub, h4 sub, h5 sub, h6 sub {
    font-size: 0.65em;
    line-height: 0;
}

h1 {
    font-size: clamp(2rem, 5vw, 3.5rem);
}

h2 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
}

h3 {
    font-size: clamp(1.25rem, 3vw, 1.75rem);
}

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

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

a:hover {
    color: var(--primary-purple);
}

/* ===========================
   Navigation
   =========================== */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: all var(--transition-base);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow-md);
}

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

.nav-brand h2 {
    font-size: 1.5rem;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin: 0;
}

.nav-brand h2 sub {
    font-size: 0.7em;
}

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

.nav-menu li a {
    color: var(--text-primary);
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    transition: all var(--transition-fast);
    border-radius: var(--radius-sm);
}

.nav-menu li a:hover {
    color: var(--primary-blue);
    background: rgba(37, 99, 235, 0.1);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.mobile-menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    border-radius: 3px;
    transition: all var(--transition-base);
}

/* ===========================
   Buttons
   =========================== */

.btn-primary, .btn-cta {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-sm);
    font-weight: 600;
    transition: all var(--transition-base);
    cursor: pointer;
    border: none;
    text-align: center;
}

.btn-primary {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: var(--white);
}

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

.btn-cta {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: var(--white);
    font-size: 1.125rem;
    padding: 1rem 2rem;
    margin-top: var(--spacing-md);
}

.btn-cta:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-xl);
}

/* ===========================
   Hero Section
   =========================== */

.hero {
    padding: calc(var(--spacing-xl) + 60px) 0 var(--spacing-xl);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: var(--white);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 20% 50%, rgba(255, 255, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(255, 255, 255, 0.1) 0%, transparent 50%);
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero-title {
    color: var(--white);
    margin-bottom: var(--spacing-sm);
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.95);
    max-width: 700px;
    margin: 0 auto var(--spacing-md);
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
    margin: var(--spacing-lg) 0;
}

.stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: var(--spacing-xs);
}

.stat-label {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.9);
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* ===========================
   Section Styles
   =========================== */

.section {
    padding: var(--spacing-xl) 0;
}

.section-header {
    text-align: center;
    max-width: 800px;
    margin: 0 auto var(--spacing-lg);
}

.section-header h2 {
    margin-bottom: var(--spacing-sm);
}

.section-header p {
    font-size: 1.125rem;
    color: var(--text-secondary);
}

/* ===========================
   Problem Section
   =========================== */

.problem-section {
    background: var(--light-bg);
}

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

.problem-card {
    background: var(--white);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    text-align: center;
}

.problem-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.problem-card .icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

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

.biofilm-explainer {
    background: var(--white);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    margin-top: var(--spacing-lg);
}

.biofilm-explainer h3 {
    text-align: center;
    margin-bottom: var(--spacing-md);
    color: var(--primary-purple);
}

.explainer-text {
    max-width: 800px;
    margin: 0 auto;
}

.explainer-text ul {
    margin: var(--spacing-md) 0;
    padding-left: var(--spacing-md);
}

.explainer-text li {
    margin-bottom: var(--spacing-xs);
    color: var(--text-secondary);
}

.highlight-text {
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1), rgba(124, 58, 237, 0.1));
    padding: var(--spacing-sm);
    border-radius: var(--radius-sm);
    border-left: 4px solid var(--primary-blue);
    margin-top: var(--spacing-md);
}

/* ===========================
   Solution Section
   =========================== */

.solution-section {
    background: var(--white);
}

.solution-highlights {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.highlight-card {
    text-align: center;
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.05), rgba(139, 92, 246, 0.05));
    transition: all var(--transition-base);
}

.highlight-card:hover {
    transform: translateY(-5px);
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(139, 92, 246, 0.1));
}

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

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

.key-benefits {
    margin-top: var(--spacing-lg);
    text-align: center;
}

.key-benefits h3 {
    margin-bottom: var(--spacing-md);
}

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

.benefit {
    background: var(--white);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    text-align: left;
}

.benefit h4 {
    color: var(--primary-purple);
    margin-bottom: var(--spacing-sm);
}

/* ===========================
   How It Works Section
   =========================== */

.how-section {
    background: var(--light-bg);
}

.steps-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.step {
    background: var(--white);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    transition: all var(--transition-base);
}

.step:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.step-number {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    flex-shrink: 0;
}

.step-content h3 {
    margin-bottom: var(--spacing-sm);
}

.safety-section {
    background: var(--white);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    margin-top: var(--spacing-lg);
}

.safety-section h3 {
    text-align: center;
    color: var(--primary-purple);
    margin-bottom: var(--spacing-md);
}

.safety-points {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-sm);
}

.safety-point {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
}

.safety-point .check {
    color: #10b981;
    font-size: 1.5rem;
    font-weight: 700;
    flex-shrink: 0;
}

.safety-point p {
    margin: 0;
}

/* ===========================
   Validation Section
   =========================== */

.validation-section {
    background: var(--white);
}

.validation-card {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.05), rgba(139, 92, 246, 0.05));
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    margin-bottom: var(--spacing-lg);
}

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

.results {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
    margin: var(--spacing-md) 0;
}

.result-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: var(--spacing-md);
    background: var(--white);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}

.result-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-blue);
    margin-bottom: var(--spacing-xs);
}

.result-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    text-align: center;
}

.validation-note {
    text-align: center;
    font-style: italic;
    color: var(--text-light);
    margin-top: var(--spacing-sm);
}

.advantages {
    margin-top: var(--spacing-lg);
}

.advantages h3 {
    text-align: center;
    margin-bottom: var(--spacing-md);
}

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

.advantage-item {
    background: var(--white);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border-left: 4px solid var(--primary-blue);
}

.advantage-item h4 {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-xs);
}

/* ===========================
   Team Section
   =========================== */

.team-section {
    background: var(--light-bg);
}

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

.team-member {
    background: var(--white);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.team-member:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.member-info h3 {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-xs);
}

.member-info .role {
    color: var(--primary-purple);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.member-info .bio {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* ===========================
   Science Section
   =========================== */

.science-section {
    background: var(--white);
}

.science-content {
    max-width: 900px;
    margin: 0 auto;
}

.science-intro {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.science-intro h3 {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-xs);
}

.author {
    font-style: italic;
    color: var(--text-light);
    font-size: 1rem;
}

.science-text {
    margin-bottom: var(--spacing-lg);
}

.science-highlight {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(139, 92, 246, 0.1));
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    border-left: 4px solid var(--primary-blue);
    margin-bottom: var(--spacing-md);
}

.science-highlight h4 {
    color: var(--primary-purple);
    margin-bottom: var(--spacing-sm);
}

.science-section-content {
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-md) 0;
}

.science-section-content h4 {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-sm);
}

.science-section-content p {
    margin-bottom: var(--spacing-sm);
    line-height: 1.8;
}

.science-cta {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.05), rgba(139, 92, 246, 0.05));
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    text-align: center;
    margin: var(--spacing-lg) 0;
}

.science-cta h4 {
    color: var(--primary-purple);
    margin-bottom: var(--spacing-sm);
}

.btn-download {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 1rem 2rem;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: var(--white);
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 1.125rem;
    transition: all var(--transition-base);
    margin-top: var(--spacing-sm);
    text-decoration: none;
}

.btn-download:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-xl);
    color: var(--white);
}

.download-icon {
    font-size: 1.5rem;
}

.key-findings {
    margin-top: var(--spacing-xl);
}

.key-findings h3 {
    text-align: center;
    color: var(--primary-purple);
    margin-bottom: var(--spacing-md);
}

.findings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.finding-card {
    background: var(--light-bg);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    text-align: center;
    transition: all var(--transition-base);
    border: 2px solid transparent;
}

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

.finding-icon {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
}

.finding-card h4 {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-xs);
    font-size: 1.125rem;
}

.finding-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
    margin: 0;
}

/* ===========================
   Contact Section
   =========================== */

.contact-section {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: var(--white);
    text-align: center;
}

.contact-content h2 {
    color: var(--white);
    margin-bottom: var(--spacing-sm);
}

.contact-content > p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-lg);
}

.contact-info {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    background: rgba(255, 255, 255, 0.1);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    backdrop-filter: blur(10px);
    transition: all var(--transition-base);
}

.contact-item:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateY(-3px);
}

.contact-icon {
    font-size: 2rem;
}

.contact-item h4 {
    color: var(--white);
    margin-bottom: var(--spacing-xs);
}

.contact-item a {
    color: var(--white);
    font-weight: 500;
}

.contact-item a:hover {
    color: rgba(255, 255, 255, 0.8);
}

.contact-item p {
    color: rgba(255, 255, 255, 0.9);
    margin: 0;
}

/* ===========================
   Footer
   =========================== */

.footer {
    background: var(--dark-bg);
    color: var(--text-white);
    padding: var(--spacing-md) 0;
}

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

.footer-brand h3 {
    color: var(--white);
    margin-bottom: var(--spacing-xs);
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.9rem;
}

.footer-legal p {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.9rem;
    margin: 0;
}

/* ===========================
   Back to Top Button
   =========================== */

.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: var(--white);
    border: none;
    border-radius: 50%;
    font-size: 1.5rem;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    box-shadow: var(--shadow-lg);
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

/* ===========================
   Animations
   =========================== */

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 0.6s ease-out forwards;
}

/* ===========================
   Responsive Design
   =========================== */

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: var(--white);
        flex-direction: column;
        padding: var(--spacing-md);
        box-shadow: var(--shadow-lg);
        transition: left var(--transition-base);
        gap: var(--spacing-sm);
        align-items: flex-start;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .mobile-menu-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(7px, 7px);
    }
    
    .mobile-menu-toggle.active span:nth-child(2) {
        opacity: 0;
    }
    
    .mobile-menu-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -7px);
    }
    
    .hero-stats {
        gap: var(--spacing-md);
    }
    
    .stat-number {
        font-size: 2rem;
    }
    
    .problem-grid,
    .solution-highlights,
    .steps-container,
    .team-grid,
    .findings-grid {
        grid-template-columns: 1fr;
    }
    
    .benefits-grid,
    .advantage-grid {
        grid-template-columns: 1fr;
    }
    
    .btn-download {
        font-size: 1rem;
        padding: 0.875rem 1.5rem;
    }
    
    .results {
        flex-direction: column;
        align-items: center;
    }
    
    .contact-info {
        flex-direction: column;
        align-items: center;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-lg: 3rem;
        --spacing-xl: 4rem;
    }
    
    .container {
        padding: 0 1rem;
    }
    
    .stat-number {
        font-size: 1.75rem;
    }
    
    .stat-label {
        font-size: 0.8rem;
    }
    
    .btn-cta {
        font-size: 1rem;
        padding: 0.875rem 1.5rem;
    }
}

/* ===========================
   Print Styles
   =========================== */

@media print {
    .navbar,
    .back-to-top,
    .btn-cta,
    .btn-primary {
        display: none;
    }
    
    .hero {
        background: var(--white);
        color: var(--text-primary);
    }
    
    .section {
        page-break-inside: avoid;
    }
}