/* Robotics World - Main stylesheet */
:root {
    --bg: #0f1419;
    --surface: #1a2332;
    --border: #2d3a4f;
    --text: #e6edf3;
    --muted: #8b949e;
    --accent: #58a6ff;
    --accent-hover: #79b8ff;
    --success: #3fb950;
    --danger: #f85149;
    --font: 'Segoe UI', system-ui, sans-serif;
    --radius: 8px;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.main-content {
    flex: 1;
    padding: 2rem 0;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 1.25rem;
}

/* Header */
.site-header {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 1rem 0;
}

.site-header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}

.logo {
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--text);
    text-decoration: none;
    letter-spacing: -0.02em;
}

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

.main-nav {
    display: flex;
    gap: 1.5rem;
}

.main-nav a {
    color: var(--muted);
    text-decoration: none;
    font-weight: 500;
}

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

/* Ad slots - placeholder for Google AdSense */
.ad-slot {
    min-height: 90px;
    margin: 1rem auto;
    max-width: 728px;
    background: var(--surface);
    border: 1px dashed var(--border);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--muted);
    font-size: 0.85rem;
}

.ad-header { min-height: 90px; }
.ad-footer { min-height: 120px; }
.ad-incontent { min-height: 250px; }
.ad-inarticle { min-height: 250px; }

/* Hero */
.hero {
    text-align: center;
    padding: 3rem 0 2rem;
}

.hero h1 {
    font-size: 2.25rem;
    margin: 0 0 0.5rem;
    font-weight: 700;
    letter-spacing: -0.03em;
}

.tagline {
    font-size: 1.1rem;
    color: var(--muted);
    max-width: 560px;
    margin: 0 auto;
}

/* Cards / quick links */
.quick-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.25rem;
    margin: 2rem 0 3rem;
}

.quick-links .card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    text-decoration: none;
    color: inherit;
    transition: border-color 0.2s, transform 0.15s;
}

.quick-links .card:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
}

.quick-links .card h2 {
    font-size: 1.15rem;
    margin: 0 0 0.5rem;
    color: var(--accent);
}

.quick-links .card p {
    margin: 0;
    font-size: 0.95rem;
    color: var(--muted);
}

/* Articles */
.latest-articles h2,
.page-articles h1,
.page-origins h1,
.page-asimov h1,
.page-about h1,
.page-article .single-article h1 {
    font-size: 1.5rem;
    margin: 0 0 1rem;
}

.article-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 1.25rem;
    margin: 1rem 0;
}

.article-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.25rem;
}

.article-card h3 {
    font-size: 1.05rem;
    margin: 0 0 0.5rem;
}

.article-card h3 a {
    color: var(--text);
    text-decoration: none;
}

.article-card h3 a:hover {
    color: var(--accent);
}

.article-card .excerpt {
    font-size: 0.9rem;
    color: var(--muted);
    margin: 0 0 0.5rem;
}

.article-card time {
    font-size: 0.8rem;
    color: var(--muted);
}

.btn {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: var(--accent);
    color: #fff !important;
    text-decoration: none;
    border-radius: var(--radius);
    font-weight: 500;
    margin-top: 0.5rem;
}

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

/* Content blocks (origins, asimov) */
.intro {
    font-size: 1.05rem;
    color: var(--muted);
    margin: 0 0 1.5rem;
}

.content-block {
    margin: 1.5rem 0;
    padding: 1rem 0;
    border-bottom: 1px solid var(--border);
}

.content-block:last-of-type {
    border-bottom: none;
}

.content-block h2 {
    font-size: 1.2rem;
    margin: 0 0 0.75rem;
}

.content-block p {
    margin: 0 0 0.5rem;
}

.three-laws {
    margin: 0.5rem 0 1rem;
    padding-left: 1.5rem;
}

.three-laws li {
    margin: 0.5rem 0;
}

.category-articles {
    margin-top: 2rem;
}

.article-list {
    list-style: none;
    padding: 0;
    margin: 0.5rem 0 0;
}

.article-list li {
    padding: 0.4rem 0;
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.article-list a {
    color: var(--accent);
    text-decoration: none;
}

.article-list a:hover {
    text-decoration: underline;
}

.article-list time {
    font-size: 0.9rem;
    color: var(--muted);
}

/* Articles listing page */
.filter-categories {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin: 1rem 0 1.5rem;
}

.filter-categories a {
    padding: 0.4rem 0.8rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--muted);
    text-decoration: none;
    font-size: 0.9rem;
}

.filter-categories a:hover,
.filter-categories a.active {
    border-color: var(--accent);
    color: var(--accent);
}

.article-list-full .article-item {
    padding: 1.25rem 0;
    border-bottom: 1px solid var(--border);
}

.article-list-full .article-item h2 {
    font-size: 1.2rem;
    margin: 0 0 0.35rem;
}

.article-list-full .article-item h2 a {
    color: var(--text);
    text-decoration: none;
}

.article-list-full .article-item h2 a:hover {
    color: var(--accent);
}

.cat-badge {
    display: inline-block;
    font-size: 0.75rem;
    background: var(--border);
    color: var(--muted);
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    margin-bottom: 0.35rem;
}

.article-list-full .excerpt {
    color: var(--muted);
    font-size: 0.95rem;
    margin: 0.25rem 0;
}

.no-articles {
    color: var(--muted);
}

/* Single article */
.page-article .category {
    margin: 0 0 0.25rem;
}

.page-article .category a {
    color: var(--accent);
    text-decoration: none;
    font-size: 0.9rem;
}

.single-article h1 {
    margin: 0 0 0.25rem;
}

.single-article time {
    font-size: 0.9rem;
    color: var(--muted);
    margin-bottom: 1rem;
    display: block;
}

.article-body {
    margin: 1.5rem 0;
}

.article-body p {
    margin: 0 0 1rem;
}

.article-body h2 {
    font-size: 1.25rem;
    margin: 1.5rem 0 0.5rem;
}

.article-body ul, .article-body ol {
    margin: 0.5rem 0 1rem;
    padding-left: 1.5rem;
}

.article-body a {
    color: var(--accent);
}

.back {
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
}

.back a {
    color: var(--muted);
    text-decoration: none;
}

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

/* About / page content */
.page-content {
    margin-top: 0.5rem;
}

.page-content p {
    margin: 0 0 1rem;
}

/* Footer */
.site-footer {
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 1.5rem 0;
    margin-top: auto;
    text-align: center;
    font-size: 0.9rem;
    color: var(--muted);
}

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

.site-footer a:hover {
    text-decoration: underline;
}

.site-footer p {
    margin: 0.25rem 0;
}