:root {
    --text-color: #292929;
    --text-secondary: #6b6b6b;
    --bg-color: #ffffff;
    --link-color: #c85c10;
    --link-hover: #a04a0d;
    --border-color: #e6e6e6;
    --accent-bg: #f7f7f7;
    --max-width: 700px;
    --homepage-width: 1000px;
    --font-serif: charter, Georgia, Cambria, "Times New Roman", Times, serif;
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* {
    box-sizing: border-box;
}

html {
    font-size: 18px;
}

body {
    font-family: var(--font-serif);
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-color);
    background: var(--bg-color);
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 2rem 1.5rem;
}

.homepage-container {
    max-width: var(--homepage-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* ===== HERO / LANDING SECTION ===== */
.site-hero {
    background: var(--bg-color);
    border-bottom: 1px solid var(--border-color);
    padding: 3rem 1.5rem;
    text-align: center;
    margin-bottom: 0;
}

.site-hero-title {
    font-family: var(--font-sans);
    font-size: 2rem;
    font-weight: 700;
    margin: 0 0 0.75rem 0;
    color: var(--text-color);
    letter-spacing: -0.02em;
}

.site-hero-tagline {
    font-family: var(--font-serif);
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin: 0 0 2rem 0;
    font-style: italic;
}

.site-hero-bio {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.hero-bio-image {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--border-color);
}

.hero-bio-text {
    max-width: 600px;
    font-family: var(--font-serif);
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-color);
}

.site-hero-mission {
    background: var(--accent-bg);
    border-left: 3px solid var(--link-color);
    border-radius: 0 6px 6px 0;
    padding: 1.5rem;
    margin: 2rem auto;
    max-width: 600px;
    font-style: italic;
    font-size: 1.05rem;
    line-height: 1.7;
}

.site-hero-mission p {
    margin: 0.5rem 0;
}

.site-hero-mission p:first-child {
    margin-top: 0;
}

.site-hero-mission p:last-child {
    margin-bottom: 0;
}

.hero-author-name {
    font-family: var(--font-sans);
    font-weight: 700;
    font-size: 1rem;
    margin: 0 0 0.5rem 0;
    color: var(--text-color);
}

.site-hero-guide {
    font-size: 0.95rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 1.5rem auto 0;
    line-height: 1.6;
}

.site-hero-stats {
    font-family: var(--font-sans);
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 0.75rem;
}

.post-list-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.category-badges {
    display: inline-flex;
    gap: 0.35rem;
    flex-wrap: wrap;
}

/* Series part links */
.series-parts {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    margin-top: 0.5rem;
}

.series-part-link {
    display: block;
    padding: 0.35rem 0;
    font-family: var(--font-sans);
    font-size: 0.85rem;
    color: var(--link-color);
    text-decoration: none;
    transition: color 0.15s;
}

.series-part-link:hover {
    color: var(--link-hover);
}

.series-part-link .part-num {
    font-weight: 600;
    margin-right: 0.25rem;
}

.series-part-link .part-title {
    color: var(--text-secondary);
}

.series-part-link:hover .part-title {
    color: var(--text-color);
}

/* ===== TAB NAVIGATION ===== */
.tab-bar {
    background: var(--accent-bg);
    border-bottom: 1px solid var(--border-color);
    padding: 0;
    margin: 0;
    font-family: var(--font-sans);
    font-size: 0.85rem;
    overflow-x: auto;
    overflow-y: hidden;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    position: sticky;
    top: 0;
    z-index: 100;
}

.tab-bar::-webkit-scrollbar {
    display: none;
}

.tab-bar-inner {
    display: flex;
    gap: 0;
    padding: 0;
    margin: 0;
    min-width: min-content;
    list-style: none;
    width: 100%;
}

.tab-item {
    flex-shrink: 0;
    position: relative;
    border-bottom: 2px solid transparent;
    transition: all 0.2s;
}

.tab-item a {
    display: block;
    padding: 1rem 1.25rem;
    color: var(--text-secondary);
    text-decoration: none;
    white-space: nowrap;
    transition: color 0.15s;
}

.tab-item a:hover {
    color: var(--text-color);
}

.tab-item.active {
    border-bottom-color: var(--link-color);
}

.tab-item.active a {
    color: var(--text-color);
    font-weight: 600;
}

/* ===== SEARCH BOX ===== */
.search-box {
    width: 100%;
    padding: 0.75rem 1rem;
    font-family: var(--font-sans);
    font-size: 0.95rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    margin: 1.5rem 0;
    background: var(--bg-color);
    color: var(--text-color);
    transition: border-color 0.15s, box-shadow 0.15s;
}

.search-box::placeholder {
    color: var(--text-secondary);
}

.search-box:focus {
    outline: none;
    border-color: var(--link-color);
    box-shadow: 0 0 0 3px rgba(200, 92, 16, 0.1);
}

/* ===== POST LIST ===== */
.post-list {
    list-style: none;
    padding: 0;
    margin: 2rem 0;
}

.post-list li {
    border-bottom: 1px solid var(--border-color);
    padding: 1.75rem 0;
}

.post-list li:first-child {
    padding-top: 0;
}

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

.post-list-title {
    font-family: var(--font-serif);
    font-size: 1.15rem;
    font-weight: 700;
    margin: 0 0 0.5rem 0;
    line-height: 1.3;
}

.post-list-title a {
    color: var(--text-color);
    text-decoration: none;
    transition: color 0.15s;
}

.post-list-title a:hover {
    color: var(--link-color);
}

.post-list-meta {
    font-family: var(--font-sans);
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.post-list-excerpt {
    margin-top: 0.75rem;
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* ===== CATEGORY BADGES ===== */
.category-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.7rem;
    font-weight: 600;
    font-family: var(--font-sans);
    text-decoration: none;
    transition: opacity 0.15s;
    color: var(--text-color);
}

.category-badge:hover {
    opacity: 0.75;
}

.category-badge.climate {
    background: #e8f4fd;
}

.category-badge.solutions {
    background: #e8f8e8;
}

.category-badge.policy {
    background: #f0e8f8;
}

.category-badge.ai {
    background: #fef8e8;
}

.category-badge.science {
    background: #e8f4f0;
}

.category-badge.notes {
    background: #f0f0f0;
}

.category-badge.series {
    background: #fef0e8;
}

/* ===== SERIES CARDS ===== */
.series-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
    margin: 2rem 0;
}

.series-card {
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.5rem;
    text-decoration: none;
    color: var(--text-color);
    transition: box-shadow 0.2s, border-color 0.2s;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.series-card:hover {
    border-color: var(--link-color);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.series-card-title {
    font-family: var(--font-serif);
    font-size: 1.15rem;
    font-weight: 700;
    margin: 0;
    color: var(--text-color);
}

.series-card:hover .series-card-title {
    color: var(--link-color);
}

.series-card-description {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0;
}

.series-card-count {
    font-family: var(--font-sans);
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: auto;
}

/* ===== INDIVIDUAL POST PAGE STYLES ===== */
header {
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1.5rem;
    margin-bottom: 2.5rem;
}

.site-title {
    font-family: var(--font-sans);
    font-size: 1.1rem;
    font-weight: 600;
    margin: 0;
    letter-spacing: -0.02em;
}

.site-title a {
    color: var(--text-color);
    text-decoration: none;
}

.site-title a:hover {
    color: var(--link-color);
}

header p {
    margin: 0.5rem 0 0 0;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

nav {
    margin-top: 1rem;
    font-family: var(--font-sans);
    font-size: 0.85rem;
}

nav a {
    color: var(--text-secondary);
    text-decoration: none;
    margin-right: 1.5rem;
    transition: color 0.15s;
}

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

article {
    margin-bottom: 3rem;
}

.post-header {
    margin-bottom: 2.5rem;
    text-align: center;
}

.post-title {
    font-family: var(--font-serif);
    font-size: 2.2rem;
    font-weight: 700;
    margin: 0 0 0.75rem 0;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

.post-meta {
    color: var(--text-secondary);
    font-family: var(--font-sans);
    font-size: 0.85rem;
}

.post-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin: 0.75rem 0;
    font-style: italic;
    font-weight: 400;
}

.post-content {
    font-size: 1.1rem;
    line-height: 1.8;
}

.post-content p {
    margin: 1.5em 0;
}

.post-content h1 {
    font-size: 1.75rem;
    margin: 2em 0 0.75em 0;
    line-height: 1.3;
}

.post-content h2 {
    font-size: 1.5rem;
    margin: 2em 0 0.75em 0;
    line-height: 1.3;
}

.post-content h3 {
    font-size: 1.25rem;
    margin: 1.75em 0 0.5em 0;
    line-height: 1.4;
}

.post-content img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 2em auto;
    border-radius: 4px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.post-content figure {
    margin: 2.5em 0;
    padding: 0;
}

.post-content figure img {
    margin: 0 auto 0.75rem auto;
}

.post-content figcaption {
    font-family: var(--font-sans);
    font-size: 0.8rem;
    color: var(--text-secondary);
    text-align: center;
    margin-top: 0.75rem;
    line-height: 1.5;
    padding: 0 2rem;
}

.post-content blockquote {
    border-left: 3px solid var(--link-color);
    margin: 2em 0;
    padding: 1em 1.5em;
    background: var(--accent-bg);
    border-radius: 0 6px 6px 0;
    font-style: italic;
}

.post-content blockquote p:first-child {
    margin-top: 0;
}

.post-content blockquote p:last-child {
    margin-bottom: 0;
}

.post-content blockquote strong {
    font-style: normal;
}

.post-content a {
    color: var(--link-color);
    text-decoration: underline;
    text-decoration-thickness: 1px;
    text-underline-offset: 2px;
    transition: color 0.15s;
}

.post-content a:hover {
    color: var(--link-hover);
}

.post-content hr {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 3em 0;
}

.post-content ul,
.post-content ol {
    padding-left: 1.75em;
    margin: 1.5em 0;
}

.post-content li {
    margin: 0.5em 0;
    line-height: 1.7;
}

.post-content strong {
    font-weight: 600;
}

.post-content em {
    font-style: italic;
}

/* ===== POST NAVIGATION ===== */
.post-nav {
    display: flex;
    justify-content: space-between;
    gap: 2rem;
    margin-top: 4rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    font-family: var(--font-sans);
    font-size: 0.9rem;
}

.post-nav a {
    color: var(--link-color);
    text-decoration: none;
    transition: color 0.15s;
}

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

.post-nav span {
    flex: 1;
}

/* ===== FOOTER ===== */
footer {
    margin-top: 4rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-family: var(--font-sans);
    font-size: 0.8rem;
}

/* ===== SEARCH HIGHLIGHTS ===== */
mark {
    background: rgba(200, 92, 16, 0.2);
    color: inherit;
    padding: 0.1em 0.2em;
    border-radius: 2px;
}

/* ===== RESPONSIVE ADJUSTMENTS ===== */
@media (max-width: 768px) {
    .series-grid {
        grid-template-columns: 1fr;
    }

    .site-hero {
        padding: 2rem 1rem;
    }

    .site-hero-title {
        font-size: 1.75rem;
    }

    .site-hero-mission {
        padding: 1.25rem;
    }

    .tab-bar-inner {
        padding: 0 1rem;
    }

    .tab-item a {
        padding: 0.75rem 1rem;
        font-size: 0.8rem;
    }
}

@media (max-width: 600px) {
    html {
        font-size: 16px;
    }

    .container {
        padding: 1.5rem 1rem;
    }

    .homepage-container {
        padding: 0 1rem;
    }

    .post-title {
        font-size: 1.75rem;
    }

    .site-hero-title {
        font-size: 1.5rem;
    }

    .site-hero-tagline {
        font-size: 1rem;
    }

    .hero-bio-image {
        width: 80px;
        height: 80px;
    }

    .post-nav {
        flex-direction: column;
        gap: 1rem;
    }

    .tab-item a {
        padding: 0.75rem 0.875rem;
        font-size: 0.75rem;
    }

    .series-card {
        padding: 1rem;
    }

    .series-card-title {
        font-size: 1rem;
    }
}