@import url('https://fonts.googleapis.com/css2?family=Montserrat:wght@400;600;700;800&family=Open+Sans:wght@400;600;700&display=swap');

:root {
    --primary-blue: #0077B6;
    --secondary-blue: #00B4D8;
    --light-blue: #ADE8F4;
    --accent-green: #2D9B4E;
    --accent-orange: #F4860A;
    --accent-yellow: #F9C74F;
    --dark-text: #1A2B3C;
    --light-bg: #F0F8FF;
    --white: #FFFFFF;
    
    --font-heading: 'Montserrat', sans-serif;
    --font-body: 'Open Sans', sans-serif;
    
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
    --shadow-lg: 0 12px 24px rgba(0,70,120,0.15);
}

html {
    scroll-behavior: smooth;
}

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

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

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    color: var(--primary-blue);
    margin-bottom: 1rem;
    line-height: 1.3;
}

a {
    color: var(--primary-blue);
    text-decoration: none;
    transition: color 0.3s;
}

a:hover {
    color: var(--secondary-blue);
}

p {
    margin-bottom: 1rem;
}

/* Header & Nav */
.site-header {
    background: linear-gradient(135deg, var(--primary-blue), var(--secondary-blue));
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-md);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
}

.logo {
    color: var(--white);
    font-family: var(--font-heading);
    font-weight: 800;
    font-size: 1.25rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

.logo:hover {
    color: var(--white);
}

/* CSS-only Hamburger Menu */
.menu-toggle {
    display: none;
}
.hamburger {
    display: none;
    color: var(--white);
    font-size: 1.5rem;
    cursor: pointer;
    user-select: none;
}

.main-nav ul {
    display: flex;
    list-style: none;
    gap: 1.25rem;
    flex-wrap: wrap;
    justify-content: center;
}

.main-nav a {
    color: rgba(255,255,255,0.9);
    font-weight: 600;
    font-size: 0.85rem;
    padding: 0.5rem 0;
    border-bottom: 2px solid transparent;
}

.main-nav a:hover, .main-nav a.active {
    color: var(--white);
    border-bottom: 2px solid var(--accent-yellow);
}

@media (max-width: 1024px) {
    .hamburger {
        display: block;
    }
    .main-nav {
        display: none;
        width: 100%;
        background: var(--primary-blue);
        position: absolute;
        top: 100%;
        left: 0;
        padding: 1rem 0;
        box-shadow: var(--shadow-md);
    }
    .main-nav ul {
        flex-direction: column;
        align-items: center;
        gap: 1rem;
    }
    .menu-toggle:checked ~ .main-nav {
        display: block;
    }
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, rgba(0, 119, 182, 0.9), rgba(0, 180, 216, 0.8)), url('data:image/svg+xml,<svg width="20" height="20" viewBox="0 0 20 20" xmlns="http://www.w3.org/2000/svg"><circle cx="2" cy="2" r="1" fill="rgba(255,255,255,0.1)"/></svg>');
    color: var(--white);
    text-align: center;
    padding: 6rem 2rem 8rem;
    position: relative;
    overflow: hidden;
}

.hero h1 {
    color: var(--white);
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    text-shadow: 0 4px 8px rgba(0,0,0,0.2);
    line-height: 1.1;
}

.hero p.subtitle {
    font-size: 1.25rem;
    max-width: 800px;
    margin: 0 auto;
    font-weight: 600;
    color: var(--light-blue);
}

/* Wave Divider */
.wave-divider {
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    overflow: hidden;
    line-height: 0;
}
.wave-divider svg {
    position: relative;
    display: block;
    width: calc(100% + 1.3px);
    height: 60px;
}
.wave-divider .shape-fill {
    fill: var(--light-bg);
}

/* Layout */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

.content-section {
    padding: 4rem 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--accent-orange);
    margin: 1rem auto 0;
    border-radius: 2px;
}

/* Cards */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.info-card {
    background: var(--white);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow-md);
    border-left: 6px solid var(--primary-blue);
    transition: transform 0.3s, box-shadow 0.3s;
}

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

.info-card h3 {
    color: var(--dark-text);
}

.info-card.green { border-left-color: var(--accent-green); }
.info-card.orange { border-left-color: var(--accent-orange); }
.info-card.yellow { border-left-color: var(--accent-yellow); }

.icon-container {
    font-size: 3rem;
    margin-bottom: 1rem;
    display: inline-block;
}

/* Stats */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin: 3rem 0;
}
.stat-box {
    background: var(--white);
    padding: 2rem 1rem;
    text-align: center;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    border-bottom: 4px solid var(--secondary-blue);
}
.stat-box .stat-number {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary-blue);
    font-family: var(--font-heading);
    margin-bottom: 0.5rem;
}
.stat-box .stat-label {
    font-size: 1rem;
    font-weight: 600;
    color: var(--dark-text);
}

/* Callout Box */
.highlight-box {
    background-color: var(--light-blue);
    border-radius: 12px;
    padding: 2rem;
    margin: 2rem 0;
    position: relative;
    border-left: 4px solid var(--primary-blue);
}

.highlight-box::before {
    content: "💡";
    font-size: 1.8rem;
    position: absolute;
    top: -15px;
    left: 20px;
    background: var(--white);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-sm);
}

/* Badges */
.badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 700;
    text-transform: uppercase;
}
.badge.primary { background: var(--primary-blue); color: var(--white); }
.badge.accent { background: var(--accent-yellow); color: var(--dark-text); }

/* Step-by-step Cards */
.process-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}
.process-card {
    display: flex;
    background: var(--white);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}
.process-number {
    background: var(--primary-blue);
    color: var(--white);
    font-family: var(--font-heading);
    font-size: 2.5rem;
    font-weight: 800;
    padding: 2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 100px;
}
.process-content {
    padding: 2rem;
}
@media (max-width: 600px) {
    .process-card { flex-direction: column; }
    .process-number { padding: 1rem; }
}

/* Timeline */
.timeline {
    position: relative;
    max-width: 800px;
    margin: 2rem auto;
    padding: 2rem 0;
}
.timeline::after {
    content: '';
    position: absolute;
    width: 6px;
    background-color: var(--secondary-blue);
    top: 0;
    bottom: 0;
    left: 50%;
    margin-left: -3px;
    border-radius: 3px;
}
.timeline-item {
    padding: 10px 40px;
    position: relative;
    background-color: inherit;
    width: 50%;
}
.timeline-item::after {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    right: -10px;
    background-color: var(--white);
    border: 4px solid var(--accent-orange);
    top: 15px;
    border-radius: 50%;
    z-index: 1;
}
.left { left: 0; }
.right { left: 50%; }
.right::after { left: -10px; }
.timeline-content {
    padding: 20px;
    background-color: var(--white);
    position: relative;
    border-radius: 8px;
    box-shadow: var(--shadow-md);
}
.timeline-content h3 { color: var(--accent-green); }
@media (max-width: 768px) {
    .timeline::after { left: 31px; }
    .timeline-item { width: 100%; padding-left: 70px; padding-right: 25px; }
    .left::after, .right::after { left: 21px; }
    .right { left: 0%; }
}

/* FAQ Accordion */
.faq-container {
    max-width: 800px;
    margin: 0 auto;
}
details.faq-item {
    background: var(--white);
    margin-bottom: 1rem;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}
details.faq-item summary {
    padding: 1.5rem;
    font-family: var(--font-heading);
    font-weight: 700;
    color: var(--primary-blue);
    cursor: pointer;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
details.faq-item summary::-webkit-details-marker { display: none; }
details.faq-item summary::after {
    content: '+';
    font-size: 1.5rem;
    transition: transform 0.3s;
}
details[open].faq-item summary::after {
    transform: rotate(45deg);
}
.faq-content {
    padding: 0 1.5rem 1.5rem;
    border-top: 1px solid var(--light-bg);
    margin-top: 0.5rem;
    padding-top: 1rem;
}

/* Glossary */
.glossary-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 2rem;
    justify-content: center;
}
.glossary-nav a {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: var(--white);
    border-radius: 4px;
    font-weight: 700;
    box-shadow: var(--shadow-sm);
}
.glossary-nav a:hover {
    background: var(--primary-blue);
    color: var(--white);
}
dl.glossary-list {
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
}
dl.glossary-list dt {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    color: var(--dark-text);
    font-weight: 700;
    margin-top: 1.5rem;
    border-bottom: 2px solid var(--light-blue);
    padding-bottom: 0.5rem;
}
dl.glossary-list dt:first-child { margin-top: 0; }
dl.glossary-list dd {
    margin-top: 1rem;
    margin-left: 0;
    color: #444;
}

/* Water Cycle Diagram */
.water-cycle-diagram {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    align-items: center;
    gap: 1rem;
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    margin: 2rem 0;
    text-align: center;
}
.cycle-node {
    padding: 1.5rem;
    background: var(--light-blue);
    border-radius: 8px;
    font-weight: 700;
    color: var(--primary-blue);
    position: relative;
    box-shadow: var(--shadow-sm);
}
.cycle-node.green { background: #d4edda; color: var(--accent-green); }
.cycle-node.orange { background: #ffe8d6; color: var(--accent-orange); }

.cycle-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: var(--secondary-blue);
}
@media (max-width: 900px) {
    .water-cycle-diagram { grid-template-columns: 1fr; }
    .cycle-arrow { transform: rotate(90deg); }
}

/* Table */
.data-table-container {
    overflow-x: auto;
}
.data-table {
    width: 100%;
    border-collapse: collapse;
    margin: 2rem 0;
    background: var(--white);
    box-shadow: var(--shadow-sm);
    border-radius: 8px;
    overflow: hidden;
    min-width: 600px;
}
.data-table th, .data-table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--light-blue);
}
.data-table th {
    background: var(--primary-blue);
    color: var(--white);
    font-family: var(--font-heading);
}
.data-table tr:last-child td { border-bottom: none; }
.data-table tr:nth-child(even) { background: #f8fbff; }

/* Breadcrumbs */
.breadcrumb {
    padding: 1rem 0;
    color: #666;
    font-size: 0.9rem;
}
.breadcrumb a {
    color: var(--primary-blue);
    font-weight: 600;
}
.breadcrumb a::after {
    content: ' / ';
    color: #666;
    font-weight: 400;
    margin: 0 0.5rem;
}

/* Footer */
.site-footer {
    background-color: var(--dark-text);
    color: var(--white);
    padding: 4rem 2rem 1rem;
    margin-top: 4rem;
}
.footer-grid {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}
.footer-col h4 {
    color: var(--accent-yellow);
    margin-bottom: 1.5rem;
}
.footer-col ul { list-style: none; }
.footer-col ul li { margin-bottom: 0.75rem; }
.footer-col ul li a {
    color: rgba(255,255,255,0.8);
}
.footer-col ul li a:hover {
    color: var(--white);
    text-decoration: underline;
}
.footer-col p {
    color: rgba(255,255,255,0.8);
}
.footer-bottom {
    max-width: 1200px;
    margin: 3rem auto 0;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(255,255,255,0.1);
    text-align: center;
    font-size: 0.85rem;
    color: rgba(255,255,255,0.6);
}
.footer-disclaimer {
    background: rgba(255,255,255,0.05);
    padding: 1.5rem;
    border-radius: 8px;
    margin-top: 1.5rem;
    border-left: 4px solid var(--accent-orange);
    color: rgba(255,255,255,0.9);
    font-style: italic;
    text-align: left;
    line-height: 1.5;
}