:root {
    /* Brand Palette - South Pole Tech Accent x Hagler Bailly Institutional Navy */
    --primary: #0b1325;          /* Deep Midnight Navy */
    --primary-light: #162447;    /* Slate Navy */
    --accent: #059669;           /* Emerald / Mint Accent */
    --accent-bright: #10b981;    /* Vibrant South Pole Green */
    --accent-light: #ecfdf5;     /* Soft Mint Wash */
    --text-dark: #0f172a;       /* Charcoal Black */
    --text-muted: #475569;      /* Cool Slate Gray */
    --bg-light: #f8fafc;        /* Off-white Light Mode */
    --bg-card: #ffffff;
    --white: #ffffff;
    --border: #e2e8f0;
    --border-dark: #1e293b;
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, sans-serif;
    scroll-behavior: smooth;
}

section, [id] {
    scroll-margin-top: 90px;
}

body {
    color: var(--text-dark);
    background-color: var(--white);
    line-height: 1.6;
    letter-spacing: -0.01em;
}

/* --- Header & Navigation --- */
header {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(226, 232, 240, 0.8);
    z-index: 1000;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.1rem 8%;
    max-width: 1400px;
    margin: 0 auto;
}

.logo {
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.6rem;
    letter-spacing: -0.02em;
}

.nexus-logo-icon {
    width: 26px;
    height: 26px;
    flex-shrink: 0;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2.2rem;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
}

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

.btn-nav {
    background-color: var(--primary);
    color: var(--white) !important;
    padding: 0.6rem 1.4rem;
    border-radius: 4px;
    font-weight: 600;
}

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

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

.menu-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--primary);
}

/* --- Hero Section --- */
.hero {
    padding: 11rem 8% 7rem;
    background: radial-gradient(circle at 80% 20%, #162447 0%, #0b1325 100%);
    color: var(--white);
    min-height: 85vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(16, 185, 129, 0.3), transparent);
}

.hero-container {
    max-width: 1100px;
    margin: 0 auto;
    width: 100%;
}

.hero-tag {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(16, 185, 129, 0.1);
    border: 1px solid rgba(16, 185, 129, 0.3);
    color: var(--accent-bright);
    padding: 0.35rem 0.9rem;
    border-radius: 30px;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 2rem;
}

.hero h1 {
    font-size: 3.6rem;
    line-height: 1.1;
    font-weight: 700;
    max-width: 850px;
    margin-bottom: 1.5rem;
    letter-spacing: -0.03em;
}

.hero p {
    font-size: 1.25rem;
    color: #94a3b8;
    max-width: 680px;
    margin-bottom: 2.5rem;
    font-weight: 400;
    line-height: 1.7;
}

.hero-btns {
    display: flex;
    gap: 1.2rem;
}

.btn-primary {
    background-color: var(--accent-bright);
    color: #0b1325;
    padding: 0.9rem 2rem;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

.btn-primary:hover {
    background-color: #34d399;
    transform: translateY(-2px);
}

.btn-secondary {
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: var(--white);
    padding: 0.9rem 2rem;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: rgba(255, 255, 255, 0.4);
}

/* --- Stats Banner (Hagler Bailly Data Focus) --- */
.stats-banner {
    background-color: var(--bg-light);
    padding: 3.5rem 8%;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 2.5rem;
    border-bottom: 1px solid var(--border);
}

.stat-item {
    border-left: 3px solid var(--accent-bright);
    padding-left: 1.2rem;
}

.stat-item h3 {
    font-size: 2.6rem;
    color: var(--primary);
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1;
    margin-bottom: 0.4rem;
}

.stat-item p {
    color: var(--text-muted);
    font-size: 0.9rem;
    font-weight: 500;
}

/* --- Services Section --- */
.services {
    padding: 7rem 8%;
    max-width: 1400px;
    margin: 0 auto;
}

.section-header {
    margin-bottom: 4rem;
}

.section-header h2 {
    font-size: 2.4rem;
    color: var(--primary);
    letter-spacing: -0.02em;
    margin-bottom: 0.75rem;
}

.section-header p {
    color: var(--text-muted);
    font-size: 1.1rem;
    max-width: 650px;
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.service-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border);
    padding: 2.5rem 2rem;
    border-radius: 6px;
    transition: var(--transition);
    position: relative;
    top: 0;
}

.service-card:hover {
    border-color: var(--accent-bright);
    top: -4px;
    box-shadow: 0 12px 30px rgba(11, 19, 37, 0.06);
}

.service-icon {
    width: 42px;
    height: 42px;
    background-color: var(--accent-light);
    color: var(--accent);
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
    font-weight: 700;
    font-size: 0.9rem;
}

.service-card h3 {
    font-size: 1.35rem;
    margin-bottom: 1rem;
    color: var(--primary);
    letter-spacing: -0.01em;
}

.service-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* --- About Section --- */
.about-section {
    padding: 7rem 8%;
    background-color: var(--bg-light);
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 4rem;
    align-items: center;
    border-top: 1px solid var(--border);
}

.about-content h2 {
    font-size: 2.4rem;
    color: var(--primary);
    letter-spacing: -0.02em;
    margin-bottom: 1.5rem;
}

.about-content p {
    color: var(--text-muted);
    font-size: 1.05rem;
    margin-bottom: 1.5rem;
}

.about-box {
    background: var(--primary);
    color: var(--white);
    padding: 3rem;
    border-radius: 8px;
    border: 1px solid var(--border-dark);
}

.about-box h3 {
    font-size: 1.4rem;
    margin-bottom: 1.5rem;
    color: var(--white);
}

.about-list {
    list-style: none;
}

.about-list li {
    position: relative;
    padding-left: 1.8rem;
    margin-bottom: 1rem;
    color: #cbd5e1;
    font-size: 0.95rem;
}

.about-list li::before {
    content: "■";
    position: absolute;
    left: 0;
    color: var(--accent-bright);
    font-size: 0.75rem;
    top: 2px;
}

/* --- Contact Form Section --- */
.contact-section {
    padding: 7rem 8%;
    background-color: var(--white);
}

.contact-container {
    max-width: 640px;
    margin: 0 auto;
    background: var(--bg-light);
    padding: 3.5rem;
    border-radius: 8px;
    border: 1px solid var(--border);
}

.contact-container h2 {
    color: var(--primary);
    font-size: 2rem;
    letter-spacing: -0.02em;
    margin-bottom: 0.3rem;
}

.contact-sub {
    color: var(--text-muted);
    margin-bottom: 2rem;
    font-size: 0.95rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.form-control {
    width: 100%;
    padding: 0.85rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 0.95rem;
    outline: none;
    background: var(--white);
    transition: var(--transition);
}

.form-control:focus {
    border-color: var(--accent-bright);
    box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.15);
}

.btn-submit {
    width: 100%;
    background-color: var(--primary);
    color: var(--white);
    padding: 1rem;
    border: none;
    border-radius: 4px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

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

.alert-success {
    background-color: var(--accent-light);
    color: var(--accent);
    padding: 1rem;
    border-radius: 4px;
    margin-bottom: 1.5rem;
    font-weight: 500;
}

/* --- Footer (South Pole Dark Mode Styling) --- */
footer {
    background-color: #060a14;
    color: #94a3b8;
    padding: 3.5rem 8%;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-container {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 2rem;
}

.footer-brand-line {
    display: flex;
    align-items: center;
    gap: 12px;
}

.brand-text {
    font-size: 0.95rem;
    color: #94a3b8;
}

.brand-text strong {
    color: #ffffff;
    font-weight: 600;
}

.footer-info p {
    color: #64748b;
    font-size: 0.9rem;
}

/* --- Mobile Responsiveness --- */
@media (max-width: 900px) {
    .about-section {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.4rem;
    }

    .menu-toggle {
        display: flex;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: var(--white);
        flex-direction: column;
        padding: 2rem;
        border-bottom: 1px solid var(--border);
    }

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

    .contact-container {
        padding: 2rem 1.5rem;
    }

    .footer-container {
        flex-direction: column;
        align-items: flex-start;
        gap: 1.2rem;
    }
}