/* ============================================
   Solar Power — Clean Technology Subdomain
   Style System — Economist Aesthetic
   ============================================ */

/* --- Reset & Base --- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --color-primary: #1a5c3a;
    --color-primary-light: #2a7a50;
    --color-primary-dark: #0f3d26;
    --color-solar: #d4940a;
    --color-solar-light: #f5c542;
    --color-solar-dark: #b07d08;
    --color-bg: #fafaf8;
    --color-bg-alt: #f3f2ee;
    --color-bg-dark: #1a1f2e;
    --color-bg-warm: #fdf8ef;
    --color-text: #2c2c2c;
    --color-text-light: #6b6b6b;
    --color-text-muted: #9a9a9a;
    --color-border: #e2e0da;
    --color-border-light: #eeedea;
    --color-white: #ffffff;
    --color-accent: #c4a35a;

    --font-serif: 'EB Garamond', 'Georgia', 'Times New Roman', serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    --container-max: 1200px;
    --container-narrow: 800px;
    --header-height: 72px;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 2rem;
}

a {
    color: inherit;
    text-decoration: none;
}

ul { list-style: none; }
img { max-width: 100%; display: block; }

h1, h2, h3, h4 {
    font-family: var(--font-serif);
    font-weight: 500;
    line-height: 1.2;
    color: var(--color-text);
}

h1 { font-size: clamp(2rem, 4vw, 3.2rem); }
h2 { font-size: clamp(1.6rem, 3vw, 2.4rem); }
h3 { font-size: clamp(1.2rem, 2vw, 1.5rem); }

p {
    color: var(--color-text-light);
    line-height: 1.7;
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    padding: 0.75rem 1.75rem;
    font-family: var(--font-sans);
    font-size: 0.875rem;
    font-weight: 500;
    letter-spacing: 0.02em;
    border: none;
    border-radius: 2px;
    cursor: pointer;
    transition: all 0.25s ease;
    text-decoration: none;
}

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

.btn-primary:hover {
    background-color: var(--color-primary-dark);
    transform: translateY(-1px);
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-primary);
    border: 1px solid var(--color-primary);
}

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

/* ============================================
   HEADER & NAVIGATION
   ============================================ */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(250, 250, 248, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border-light);
    transition: box-shadow 0.3s ease;
}

.site-header.scrolled {
    box-shadow: 0 1px 12px rgba(0, 0, 0, 0.06);
}

.nav-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-height);
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
}

.logo-mark {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: var(--color-primary);
    color: var(--color-white);
    font-family: var(--font-serif);
    font-size: 0.875rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    border-radius: 2px;
}

.logo-text {
    font-family: var(--font-serif);
    font-size: 1.125rem;
    font-weight: 500;
    color: var(--color-text);
    letter-spacing: -0.01em;
}

.logo-text .logo-sub {
    color: var(--color-text-muted);
    font-size: 0.875rem;
    margin-left: 0.25rem;
}

.nav-links {
    display: flex;
    gap: 2.5rem;
    align-items: center;
}

.nav-links a {
    font-family: var(--font-sans);
    font-size: 0.8125rem;
    font-weight: 400;
    color: var(--color-text-light);
    letter-spacing: 0.04em;
    text-transform: uppercase;
    padding: 0.25rem 0;
    position: relative;
    transition: color 0.2s ease;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1.5px;
    background: var(--color-primary);
    transition: width 0.3s ease;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--color-primary);
}

.nav-links a.active::after,
.nav-links a:hover::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle span {
    display: block;
    width: 22px;
    height: 1.5px;
    background: var(--color-text);
    transition: all 0.3s ease;
}

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

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

.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ============================================
   HERO
   ============================================ */
.hero {
    padding-top: calc(var(--header-height) + 5rem);
    padding-bottom: 5rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    max-width: var(--container-max);
    margin: 0 auto;
    padding-left: 2rem;
    padding-right: 2rem;
    align-items: center;
}

.hero-eyebrow {
    font-family: var(--font-sans);
    font-size: 0.75rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--color-solar-dark);
    margin-bottom: 1.25rem;
}

.hero h1 {
    margin-bottom: 1.5rem;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.0625rem;
    line-height: 1.7;
    color: var(--color-text-light);
    margin-bottom: 2.5rem;
    max-width: 520px;
}

.hero-actions {
    display: flex;
    gap: 1rem;
}

.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.data-graphic {
    width: 100%;
    max-width: 500px;
    background: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: 4px;
    padding: 1.5rem;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.04);
}

.hero-chart {
    width: 100%;
    height: auto;
}

.chart-label {
    font-family: var(--font-sans);
    font-size: 9px;
    fill: var(--color-text-muted);
}

.chart-title {
    font-family: var(--font-serif);
    font-size: 12px;
    fill: var(--color-text);
    font-weight: 500;
}

/* ============================================
   METRICS
   ============================================ */
.metrics {
    background: var(--color-white);
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    padding: 3.5rem 0;
}

.metrics-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
}

.metric-card {
    text-align: center;
    padding: 1rem;
}

.metric-value {
    font-family: var(--font-serif);
    font-size: 3rem;
    font-weight: 500;
    color: var(--color-primary);
    line-height: 1;
}

.metric-unit {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    color: var(--color-primary);
    margin-left: 0.15rem;
}

.metric-label {
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    margin-top: 0.5rem;
    line-height: 1.4;
}

/* ============================================
   CONTENT SECTIONS
   ============================================ */
.content-section {
    padding: 5rem 0;
}

.content-section-alt {
    background: var(--color-bg-alt);
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
}

.content-section-warm {
    background: var(--color-bg-warm);
    border-top: 1px solid #efe4cf;
    border-bottom: 1px solid #efe4cf;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 2.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--color-border);
}

.section-header h2 {
    font-size: 1.5rem;
}

.section-link {
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--color-primary);
    letter-spacing: 0.02em;
    transition: opacity 0.2s;
}

.section-link:hover {
    opacity: 0.7;
}

/* Two-column layout */
.two-col {
    display: grid;
    grid-template-columns: 1.6fr 1fr;
    gap: 3.5rem;
    align-items: start;
}

.prose p {
    font-size: 1rem;
    line-height: 1.85;
    margin-bottom: 1.25rem;
}

.prose p:last-child {
    margin-bottom: 0;
}

/* Sidebar cards */
.sidebar-card {
    background: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: 3px;
    padding: 1.75rem;
    margin-bottom: 1.5rem;
}

.content-section-alt .sidebar-card {
    background: var(--color-white);
}

.sidebar-card h4 {
    font-family: var(--font-sans);
    font-size: 0.6875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-text-muted);
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--color-border-light);
}

/* Data points grid */
.data-points-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

.data-point {
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
}

.data-point-value {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--color-primary);
    line-height: 1.2;
}

.data-point-label {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    line-height: 1.3;
}

/* Tech list */
.tech-list li {
    font-size: 0.8125rem;
    color: var(--color-text-light);
    padding: 0.5rem 0;
    padding-left: 1rem;
    position: relative;
    border-bottom: 1px solid var(--color-border-light);
    line-height: 1.5;
}

.tech-list li:last-child {
    border-bottom: none;
}

.tech-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.85rem;
    width: 5px;
    height: 1px;
    background: var(--color-primary);
}

/* ============================================
   CARDS GRID
   ============================================ */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
}

.card {
    background: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: 3px;
    padding: 2rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
}

.card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.06);
    border-color: var(--color-primary);
}

.card-icon {
    width: 40px;
    height: 40px;
    margin-bottom: 1.25rem;
    color: var(--color-solar-dark);
}

.card-icon svg {
    width: 100%;
    height: 100%;
}

.card h3 {
    font-size: 1.125rem;
    margin-bottom: 0.75rem;
}

.card p {
    font-size: 0.875rem;
    line-height: 1.6;
}

.card-tag {
    display: inline-block;
    font-size: 0.6875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-solar-dark);
    background: rgba(212, 148, 10, 0.1);
    padding: 0.25rem 0.625rem;
    border-radius: 2px;
    margin-bottom: 1rem;
}

/* ============================================
   BAR CHART
   ============================================ */
.bar-chart {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.bar-row {
    display: grid;
    grid-template-columns: 110px 1fr;
    gap: 1rem;
    align-items: center;
}

.bar-label {
    font-size: 0.8125rem;
    color: var(--color-text-light);
    text-align: right;
}

.bar-track {
    background: var(--color-bg-alt);
    border-radius: 2px;
    height: 22px;
    position: relative;
}

.bar-fill {
    height: 100%;
    background: var(--color-primary);
    border-radius: 2px;
    position: relative;
    transition: width 1.2s ease;
}

.bar-fill-solar {
    background: var(--color-solar);
}

.bar-fill-muted {
    background: var(--color-text-muted);
    opacity: 0.4;
}

.bar-fill::after {
    content: attr(data-value);
    position: absolute;
    right: -4px;
    top: 50%;
    transform: translate(100%, -50%);
    font-family: var(--font-sans);
    font-size: 0.6875rem;
    font-weight: 600;
    color: var(--color-text);
    padding-left: 6px;
    white-space: nowrap;
}

/* ============================================
   SNAPSHOT / DATA CARDS
   ============================================ */
.snapshot-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.snapshot-card {
    background: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: 3px;
    padding: 2rem;
}

.snapshot-card h4 {
    font-family: var(--font-sans);
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 1.5rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--color-border-light);
}

/* ============================================
   TIMELINE
   ============================================ */
.timeline {
    position: relative;
    padding-left: 2rem;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--color-border);
}

.timeline-item {
    position: relative;
    padding-bottom: 2.5rem;
}

.timeline-item:last-child {
    padding-bottom: 0;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -2rem;
    top: 0.25rem;
    width: 10px;
    height: 10px;
    background: var(--color-solar);
    border: 2px solid var(--color-white);
    border-radius: 50%;
    transform: translateX(-4px);
}

.timeline-year {
    font-family: var(--font-serif);
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: 0.35rem;
}

.timeline-text {
    font-size: 0.875rem;
    color: var(--color-text-light);
    line-height: 1.6;
}

/* ============================================
   TABLE
   ============================================ */
.data-table-wrapper {
    overflow-x: auto;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

.data-table thead th {
    font-family: var(--font-sans);
    font-size: 0.6875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text-muted);
    text-align: left;
    padding: 0.75rem 1rem;
    border-bottom: 2px solid var(--color-border);
    white-space: nowrap;
}

.data-table tbody td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--color-border-light);
    color: var(--color-text-light);
}

.data-table tbody tr:hover {
    background: var(--color-bg-alt);
}

.data-table .num {
    font-family: var(--font-serif);
    font-weight: 500;
    color: var(--color-text);
}

.data-table .highlight {
    color: var(--color-primary);
    font-weight: 600;
}

/* ============================================
   NEWSLETTER
   ============================================ */
.newsletter {
    padding: 4rem 0;
    background: var(--color-bg-alt);
    border-top: 1px solid var(--color-border);
}

.newsletter-content {
    text-align: center;
    max-width: 480px;
    margin: 0 auto;
}

.newsletter-content h2 {
    font-size: 1.5rem;
    margin-bottom: 0.75rem;
}

.newsletter-content p {
    font-size: 0.9375rem;
    margin-bottom: 1.5rem;
}

.newsletter-form {
    display: flex;
    gap: 0.5rem;
}

.newsletter-form input[type="email"] {
    flex: 1;
    padding: 0.75rem 1rem;
    border: 1px solid var(--color-border);
    border-radius: 2px;
    font-family: var(--font-sans);
    font-size: 0.875rem;
    background: var(--color-white);
    outline: none;
    transition: border-color 0.2s;
}

.newsletter-form input[type="email"]:focus {
    border-color: var(--color-primary);
}

/* ============================================
   FOOTER
   ============================================ */
.site-footer {
    background: var(--color-bg-dark);
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding: 3.5rem 0 2rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 3rem;
}

.footer-brand .nav-logo {
    margin-bottom: 1rem;
}

.footer-brand .logo-text {
    color: var(--color-white);
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.45);
    font-size: 0.875rem;
    max-width: 280px;
}

.footer-links h4 {
    font-family: var(--font-sans);
    font-size: 0.6875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: rgba(255, 255, 255, 0.4);
    margin-bottom: 1.25rem;
}

.footer-links ul li {
    margin-bottom: 0.625rem;
}

.footer-links a {
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.65);
    transition: color 0.2s;
}

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

.footer-bottom {
    margin-top: 3rem;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-bottom p {
    font-size: 0.8125rem;
    color: rgba(255, 255, 255, 0.3);
}

.footer-bottom a {
    color: rgba(255, 255, 255, 0.45);
    font-size: 0.8125rem;
    transition: color 0.2s;
}

.footer-bottom a:hover {
    color: rgba(255, 255, 255, 0.8);
}

/* ============================================
   CALLOUT BOX
   ============================================ */
.callout {
    background: var(--color-bg-warm);
    border-left: 3px solid var(--color-solar);
    padding: 1.5rem 1.75rem;
    border-radius: 0 3px 3px 0;
    margin: 2rem 0;
}

.callout p {
    font-size: 0.9375rem;
    color: var(--color-text);
    font-style: italic;
    font-family: var(--font-serif);
    line-height: 1.7;
}

.callout cite {
    display: block;
    margin-top: 0.75rem;
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    font-style: normal;
}

/* ============================================
   TOPIC TAGS
   ============================================ */
.topic-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.375rem;
    margin-top: 1rem;
}

.topic {
    font-size: 0.6875rem;
    color: var(--color-text-muted);
    background: var(--color-bg-alt);
    padding: 0.2rem 0.6rem;
    border-radius: 2px;
    letter-spacing: 0.02em;
}

/* ============================================
   TOC - Table of Contents
   ============================================ */
.toc {
    position: sticky;
    top: calc(var(--header-height) + 2rem);
}

.toc h4 {
    font-family: var(--font-sans);
    font-size: 0.6875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-text-muted);
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--color-border-light);
}

.toc-links li {
    margin-bottom: 0.5rem;
}

.toc-links a {
    font-size: 0.8125rem;
    color: var(--color-text-light);
    transition: color 0.2s;
    display: block;
    padding: 0.25rem 0;
    padding-left: 0.75rem;
    border-left: 2px solid transparent;
}

.toc-links a:hover,
.toc-links a.active {
    color: var(--color-primary);
    border-left-color: var(--color-primary);
}

/* ============================================
   ANIMATIONS
   ============================================ */
.fade-in {
    opacity: 0;
    transform: translateY(16px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Counter animation */
.counter-animate {
    display: inline-block;
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 1024px) {
    .hero {
        grid-template-columns: 1fr;
        gap: 3rem;
        padding-top: calc(var(--header-height) + 3rem);
    }

    .hero-visual {
        order: -1;
    }

    .two-col {
        grid-template-columns: 1fr;
        gap: 2.5rem;
    }

    .cards-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 2rem;
    }

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

    .toc {
        position: static;
    }
}

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

    .nav-links {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: var(--color-bg);
        flex-direction: column;
        padding: 2rem;
        gap: 1.5rem;
        border-bottom: 1px solid var(--color-border);
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: all 0.3s ease;
    }

    .nav-links.open {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
    }

    .hero {
        padding-top: calc(var(--header-height) + 2.5rem);
        padding-bottom: 3rem;
    }

    .metrics-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .data-points-grid {
        grid-template-columns: 1fr 1fr;
    }

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

    .hero-actions {
        flex-direction: column;
    }

    .newsletter-form {
        flex-direction: column;
    }

    .section-header {
        flex-direction: column;
        gap: 0.5rem;
    }

    .bar-row {
        grid-template-columns: 90px 1fr;
    }

    .footer-bottom {
        flex-direction: column;
        gap: 0.5rem;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1.25rem;
    }

    .metric-value {
        font-size: 2.25rem;
    }

    .metrics-grid {
        grid-template-columns: 1fr 1fr;
        gap: 1rem;
    }

    .data-points-grid {
        grid-template-columns: 1fr;
    }

    .bar-row {
        grid-template-columns: 80px 1fr;
        gap: 0.5rem;
    }

    .bar-label {
        font-size: 0.75rem;
    }
}