/* ===========================
   Global Styles & Variables
   =========================== */

:root {
    --primary-color: #FFD700;
    --primary-dark: #FFC700;
    --text-dark: #000000;
    --text-light: #666666;
    --bg-light: #F5F5F5;
    --bg-white: #FFFFFF;
    --bg-dark: #000000;
    --border-color: #E0E0E0;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.15);
    
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-display: 'Montserrat', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    color: var(--text-dark);
    background-color: var(--bg-white);
    line-height: 1.6;
}

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

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

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.2;
}

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

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

h3 {
    font-size: 1.5rem;
}

p {
    font-size: 1rem;
    line-height: 1.7;
}

/* ===========================
   Header & Navigation
   =========================== */

.header {
    position: sticky;
    top: 0;
    z-index: 100;
    background-color: var(--bg-white);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow);
}

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

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    text-decoration: none;
    color: var(--text-dark);
}

.logo-img {
    height: 40px;
    width: auto;
}

.logo-text {
    font-size: 1.25rem;
    font-weight: 700;
    display: none;
}

@media (min-width: 768px) {
    .logo-text {
        display: inline;
    }
}

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

@media (min-width: 768px) {
    .nav {
        display: flex;
    }
}

.nav-link {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-dark);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.language-selector {
    display: none;
    gap: var(--spacing-xs);
}

@media (min-width: 768px) {
    .language-selector {
        display: flex;
    }
}

.lang-btn {
    background: none;
    border: none;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-dark);
    cursor: pointer;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
    transition: all 0.3s ease;
}

.lang-btn:hover,
.lang-btn.active {
    background-color: var(--primary-color);
    color: var(--text-dark);
}

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

@media (min-width: 768px) {
    .menu-toggle {
        display: none;
    }
}

.menu-toggle span {
    width: 25px;
    height: 3px;
    background-color: var(--text-dark);
    border-radius: 2px;
    transition: all 0.3s ease;
}

.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(8px, 8px);
}

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

.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(8px, -8px);
}

/* Mobile Menu */
.mobile-menu {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    background-color: var(--bg-white);
    border-bottom: 1px solid var(--border-color);
    flex-direction: column;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
}

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

.mobile-nav-link {
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-dark);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

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

.hero {
    background: linear-gradient(135deg, #000000 0%, #1a1a1a 100%);
    color: white;
    padding: var(--spacing-2xl) 0;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 400px;
    height: 400px;
    background-color: var(--primary-color);
    opacity: 0.05;
    border-radius: 50%;
    filter: blur(80px);
}

.hero::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 400px;
    height: 400px;
    background-color: var(--primary-color);
    opacity: 0.05;
    border-radius: 50%;
    filter: blur(80px);
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    margin-bottom: var(--spacing-md);
    line-height: 1.3;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: var(--spacing-lg);
}

.hero-buttons {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    justify-content: center;
    align-items: center;
}

@media (min-width: 640px) {
    .hero-buttons {
        flex-direction: row;
    }
}

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

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-lg);
    text-decoration: none;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    cursor: pointer;
    gap: 0.5rem;
}

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

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

.btn-secondary {
    background-color: transparent;
    color: white;
    border-color: white;
}

.btn-secondary:hover {
    background-color: white;
    color: var(--text-dark);
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.1rem;
}

/* ===========================
   Stats Section
   =========================== */

.stats {
    background-color: var(--bg-white);
    padding: var(--spacing-2xl) 0;
    border-bottom: 1px solid var(--border-color);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    font-weight: 800;
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
}

.stat-label {
    font-size: 1rem;
    color: var(--text-light);
    font-weight: 500;
}

/* ===========================
   About Section
   =========================== */

.about {
    background-color: var(--bg-light);
    padding: var(--spacing-2xl) 0;
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--text-dark);
}

.about-text {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    color: var(--text-light);
    line-height: 1.8;
}

/* ===========================
   Edge Section
   =========================== */

.edge {
    background-color: var(--bg-white);
    padding: var(--spacing-2xl) 0;
}

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

.edge-card {
    background-color: var(--bg-light);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

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

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

.edge-title {
    margin-bottom: var(--spacing-sm);
    color: var(--text-dark);
}

.edge-description {
    color: var(--text-light);
    line-height: 1.7;
}

/* ===========================
   Services Section
   =========================== */

.services {
    background-color: var(--bg-light);
    padding: var(--spacing-2xl) 0;
}

.services-description {
    max-width: 800px;
    margin: var(--spacing-lg) auto;
    text-align: center;
    color: var(--text-light);
    line-height: 1.8;
}

.services-cta {
    text-align: center;
    margin-top: var(--spacing-xl);
}

/* ===========================
   Partners Section
   =========================== */

.partners {
    background-color: var(--bg-white);
    padding: var(--spacing-2xl) 0;
}

.partners-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.partner-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    border: 2px solid;
    min-height: 150px;
    transition: all 0.3s ease;
    text-align: center;
}

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

.partner-card.official {
    background: linear-gradient(135deg, #E3F2FD 0%, #BBDEFB 100%);
    border-color: #90CAF9;
}

.partner-card.upstream {
    background: linear-gradient(135deg, #E8F5E9 0%, #C8E6C9 100%);
    border-color: #81C784;
}

.partner-card.downstream {
    background: linear-gradient(135deg, #F3E5F5 0%, #E1BEE7 100%);
    border-color: #CE93D8;
}

.partner-logo {
    font-size: 1.75rem;
    font-weight: 800;
    margin-bottom: var(--spacing-sm);
}

.partner-card.official .partner-logo {
    color: #1976D2;
}

.partner-card.upstream .partner-logo {
    color: #388E3C;
}

.partner-card.downstream .partner-logo {
    color: #7B1FA2;
}

.partner-name {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-dark);
}

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

.contact {
    background-color: var(--bg-dark);
    color: white;
    padding: var(--spacing-2xl) 0;
    text-align: center;
}

.contact .section-title {
    color: white;
}

.contact-subtitle {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.8);
    margin: var(--spacing-lg) 0;
}

.contact-cta {
    margin-top: var(--spacing-xl);
}

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

.footer {
    background-color: var(--bg-dark);
    color: white;
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

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

.footer-section h4 {
    margin-bottom: var(--spacing-md);
    color: white;
}

.footer-logo {
    height: 40px;
    width: auto;
    margin-bottom: var(--spacing-md);
}

.footer-description {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.7;
}

.footer-section ul {
    list-style: none;
}

.footer-section li {
    margin-bottom: var(--spacing-sm);
}

.footer-section a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.footer-bottom {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    padding-top: var(--spacing-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
}

@media (min-width: 768px) {
    .footer-bottom {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        text-align: left;
    }
}

.copyright {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9rem;
}

.footer-links {
    display: flex;
    gap: var(--spacing-lg);
    justify-content: center;
}

@media (min-width: 768px) {
    .footer-links {
        justify-content: flex-end;
    }
}

.footer-links a {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9rem;
}

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

@media (max-width: 768px) {
    .container {
        padding: 0 var(--spacing-md);
    }

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

    .hero-subtitle {
        font-size: 1rem;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-md);
    }

    .edge-grid {
        grid-template-columns: 1fr;
    }

    .partners-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-md);
    }

    .footer-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-lg: 1.5rem;
        --spacing-xl: 2rem;
        --spacing-2xl: 2.5rem;
    }

    h1 {
        font-size: 1.75rem;
    }

    h2 {
        font-size: 1.5rem;
    }

    .stat-number {
        font-size: 2rem;
    }

    .hero-buttons {
        gap: var(--spacing-sm);
    }

    .btn {
        padding: 0.625rem 1.25rem;
        font-size: 0.9rem;
    }

    .partners-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-sm);
    }

    .partner-card {
        min-height: 120px;
        padding: var(--spacing-md);
    }
}

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

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

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

/* ===========================
   Utility Classes
   =========================== */

.text-center {
    text-align: center;
}

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

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