:root {
    --primary-navy: #004ea2;
    --primary-navy-dark: #003a7a;
    --secondary-blue: #007bff;
    --accent-blue: #eef4fb;
    --text-dark: #2c3e50;
    --text-light: #64748b;
    --white: #ffffff;
    --bg-light: #f8fafc;
    --theme-color: #2B587A;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --font-family-base: 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

body {
    font-family: var(--font-family-base);
    color: var(--text-dark);
    background-color: var(--bg-light);
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
}

/* ==================
   NAVIGATION
   ================== */
.navbar-custom {
    background-color: var(--primary-navy);
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s ease;
}

.navbar-brand-group {
    display: flex;
    align-items: center;
    gap: 20px;
}

.nav-logo {
    height: 50px;
    object-fit: contain;
}

.logo-white-filter {
    filter: brightness(0) invert(1);
}

.nav-links {
    display: flex;
    gap: 30px;
    align-items: center;
}

.nav-link {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    font-weight: 500;
    font-size: 1rem;
    transition: color 0.2s;
    cursor: pointer;
}

.nav-link:hover {
    color: var(--white);
    text-decoration: none;
}

.nav-link.active {
    color: var(--white);
    font-weight: 700;
    border-bottom: 2px solid var(--white);
}

.btn-nav-cta {
    background-color: var(--white);
    color: var(--primary-navy);
    padding: 0.5rem 1.25rem;
    border-radius: 4px;
    font-weight: 600;
    text-decoration: none;
    transition: transform 0.2s;
}

.btn-nav-cta:hover {
    transform: translateY(-1px);
    text-decoration: none;
    color: var(--primary-navy);
}

/* ==================
   HERO SECTION
   ================== */
.hero-section {
    position: relative;
    height: 85vh;
    width: 100%;
    background: linear-gradient(135deg, var(--primary-navy) 0%, #007bff 100%);
    color: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    box-shadow: inset 0 0 100px rgba(0,0,0,0.2);
}

.modern-card {
    background: var(--white);
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid rgba(0,0,0,0.05);
}

.modern-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.12);
}

.btn-gradient {
    background: linear-gradient(135deg, var(--primary-navy) 0%, var(--secondary-blue) 100%);
    color: white !important;
    border: none;
    border-radius: 30px;
    padding: 12px 30px;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 78, 162, 0.3);
}

.btn-gradient:hover {
    transform: scale(1.05);
    box-shadow: 0 8px 25px rgba(0, 78, 162, 0.4);
}

.hero-bg-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url('https://images.unsplash.com/photo-1468420135394-1b6138445718?ixlib=rb-1.2.1&auto=format&fit=crop&w=1950&q=80'); /* Placeholder high-quality water image */
    background-size: cover;
    background-position: center;
    opacity: 0.2;
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 900px;
    padding: 0 20px;
}

.hero-title {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 300;
    margin-bottom: 2.5rem;
    opacity: 0.9;
    line-height: 1.5;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
}

.btn-primary-lg {
    background-color: var(--white);
    color: var(--primary-navy);
    padding: 1rem 2.5rem;
    border-radius: 4px;
    font-size: 1.1rem;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

.btn-primary-lg:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
    background-color: #f8fafc;
    color: var(--primary-navy);
}

.btn-outline-lg {
    background-color: transparent;
    color: var(--white);
    border: 2px solid var(--white);
    padding: 1rem 2.5rem;
    border-radius: 4px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

.btn-outline-lg:hover {
    background-color: rgba(255,255,255,0.1);
    transform: translateY(-2px);
    color: var(--white);
}

/* ==================
   CARDS & GRID
   ================== */
.content-section {
    padding: 80px 20px;
    background-color: var(--white);
}

.section-container {
    max-width: 1200px;
    margin: 0 auto;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-title {
    font-size: 2.5rem;
    color: var(--primary-navy);
    font-weight: 700;
    margin-bottom: 15px;
}

.section-desc {
    font-size: 1.2rem;
    color: var(--text-light);
    max-width: 700px;
    margin: 0 auto;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--white);
    border-radius: 8px;
    padding: 40px 30px;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border-top: 4px solid var(--primary-navy);
    text-align: left;
}

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

.feature-icon {
    font-size: 2.5rem;
    color: var(--primary-navy);
    margin-bottom: 20px;
}

.feature-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 15px;
}

.feature-text {
    color: var(--text-light);
    line-height: 1.6;
}

/* ==================
   DASHBOARD STYLES
   ================== */
.dashboard-wrapper {
    background-color: #f1f5f9;
    min-height: 100vh;
}

.dashboard-container {
    max-width: 1600px;
    margin: 0 auto;
    padding: 30px;
}

/* Sidebar/Filter styles */
.filters-panel {
    background-color: var(--white);
    border-radius: 8px;
    padding: 25px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 30px;
    border-left: 5px solid var(--primary-navy);
}

.panel-title {
    color: var(--primary-navy);
    font-weight: 600;
    font-size: 1.2rem;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

/* Plot Containers */
.graph-card {
    background-color: var(--white);
    border-radius: 8px;
    padding: 20px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 25px;
    transition: box-shadow 0.2s;
}

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

/* Tab Overrides */
.nav-tabs {
    border-bottom: 2px solid #e2e8f0;
}

.nav-tabs .nav-link {
    border: none;
    color: var(--text-light);
    font-weight: 600;
    padding: 15px 25px;
    transition: all 0.2s;
}

.nav-tabs .nav-link:hover {
    color: var(--primary-navy);
    background-color: transparent;
    border-color: transparent;
}

.nav-tabs .nav-link.active {
    color: var(--primary-navy);
    background-color: transparent;
    border-bottom: 3px solid var(--primary-navy);
}

/* Markdown Text Content */
.markdown-content {
    font-size: 1.05rem;
    line-height: 1.8;
    color: var(--text-dark);
    text-align: justify;
}

.markdown-content h1, .markdown-content h2, .markdown-content h3 {
    color: var(--primary-navy);
    margin-top: 1.5rem;
    margin-bottom: 1rem;
}

/* Footer */
.site-footer {
    background-color: var(--primary-navy);
    color: var(--white);
    padding: 60px 0;
    margin-top: 60px;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    padding: 0 20px;
}

.footer-col h4 {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 20px;
    opacity: 0.9;
}

.footer-links {
    list-style: none;
    padding: 0;
}

.footer-links li {
    margin-bottom: 10px;
}

.footer-links a {
    color: rgba(255,255,255,0.7);
    text-decoration: none;
    transition: color 0.2s;
}

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

.footer-bottom {
    text-align: center;
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 30px;
    margin-top: 40px;
    color: rgba(255,255,255,0.5);
    font-size: 0.9rem;
}

/* Header Tabs Overrides */
.header-tabs {
    border-bottom: none !important;
}

.header-tabs .nav-link {
    color: #ffffff !important;
    font-weight: 600;
}

.header-tabs .nav-link:hover {
    color: var(--white) !important;
    border-color: transparent !important;
}

.header-tabs .nav-link.active {
    color: var(--white) !important;
    background-color: transparent !important;
    border-color: transparent !important;
    border-bottom: 3px solid var(--white) !important;
}