/* ---- Theme ---- */
:root {
    --color-bg: #0D0D0D;
    --color-surface: #1A1A1A;
    --color-text: #E8E4DF;
    --color-text-muted: #8A8580;
    --color-accent: #D4A853;
    --color-accent-hover: #E0B86A;
    --color-code: #7B9EB8;
    --color-border: #2A2A2A;
    --color-border-hover: #3A3A3A;
    --color-success: #6BA368;
    --font-heading: 'Space Grotesk', system-ui, sans-serif;
    --font-body: 'Source Serif 4', Georgia, 'Times New Roman', serif;
    --font-mono: 'JetBrains Mono', ui-monospace, 'Cascadia Code', monospace;
    --space-xs: 0.25rem; --space-sm: 0.5rem; --space-md: 1rem;
    --space-lg: 1.5rem; --space-xl: 2.5rem; --space-2xl: 4rem;
    --space-3xl: 6rem; --space-section: 4rem;
    --radius-sm: 4px; --radius-md: 6px; --radius-lg: 8px;
    --transition-fast: 150ms ease; --transition: 200ms ease;
    --max-width: 896px; --max-width-wide: 1140px;
}

/* ---- Reset ---- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }

/* ---- Base ---- */
html { font-size: 16px; }
body {
    font-family: var(--font-body);
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
}

.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

/* ---- Header ---- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    padding: var(--space-lg) 0;
    background: rgba(13, 13, 13, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
}

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

.site-title {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: 0.02em;
}

.site-header .nav-links {
    display: flex;
    gap: var(--space-lg);
}

.site-header .nav-links a {
    font-family: var(--font-heading);
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--color-text-muted);
    transition: color var(--transition);
}

.site-header .nav-links a:hover {
    color: var(--color-text);
}

/* ---- Hero ---- */
.hero {
    padding: var(--space-section) 0 var(--space-2xl);
}

.hero h1 {
    font-family: var(--font-heading);
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 0.75rem;
}

.hero p {
    font-family: var(--font-body);
    font-size: 1.125rem;
    color: var(--color-text-muted);
    max-width: 480px;
}

/* ---- Posts List ---- */
.posts {
    display: flex;
    flex-direction: column;
    gap: 1px;
}

.post-link {
    display: block;
    padding: var(--space-lg) 0;
    border-bottom: 1px solid var(--color-border);
    transition: border-color var(--transition);
}

.post-link:first-child {
    border-top: 1px solid var(--color-border);
}

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

.post-link h2 {
    font-family: var(--font-heading);
    font-size: 1.375rem;
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: 0.375rem;
}

.post-link .post-meta {
    font-family: var(--font-heading);
    font-weight: 500;
    font-size: 0.8125rem;
    color: var(--color-text-muted);
}

.post-link .post-excerpt {
    margin-top: var(--space-sm);
    font-size: 0.9375rem;
    color: var(--color-text-muted);
    line-height: 1.5;
}

/* ---- Empty State ---- */
.empty-state {
    padding: var(--space-3xl) 0;
    text-align: center;
}

.empty-state p {
    color: var(--color-text-muted);
    font-size: 1rem;
}

/* ---- Post Page ---- */
.post-header {
    padding: var(--space-section) 0 var(--space-xl);
}

.post-header h1 {
    font-family: var(--font-heading);
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 0.75rem;
}

.post-header .post-meta {
    font-family: var(--font-heading);
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

.post-content {
    padding-bottom: var(--space-section);
}

.post-content h2 {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 600;
    margin: var(--space-xl) 0 var(--space-md);
}

.post-content h3 {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 600;
    margin: var(--space-xl) 0 0.75rem;
}

.post-content p {
    margin-bottom: 1.25rem;
}

.post-content ul, .post-content ol {
    margin-bottom: 1.25rem;
    padding-left: var(--space-lg);
}

.post-content li {
    margin-bottom: 0.375rem;
}

.post-content blockquote {
    border-left: 3px solid var(--color-accent);
    padding-left: 1.25rem;
    margin: var(--space-lg) 0;
    color: var(--color-text-muted);
    font-style: italic;
}

.post-content pre {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    overflow-x: auto;
    margin-bottom: 1.25rem;
    font-size: 0.875rem;
    line-height: 1.5;
}

.post-content code {
    font-family: var(--font-mono);
    font-size: 0.875em;
    color: var(--color-code);
    white-space: pre-wrap;
    word-break: break-word;
}

.post-content p code {
    background: var(--color-surface);
    padding: 0.15em 0.4em;
    border-radius: var(--radius-sm);
}

.post-content a {
    color: var(--color-accent);
    text-decoration: underline;
    text-underline-offset: 2px;
    transition: color var(--transition);
}

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

.post-content img {
    border-radius: var(--radius-md);
    margin: var(--space-lg) 0;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    font-family: var(--font-heading);
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--color-text-muted);
    transition: color var(--transition);
    margin-bottom: var(--space-md);
}

.back-link:hover {
    color: var(--color-text);
}

/* ---- Series Nav ---- */
.series-nav {
    margin-top: var(--space-xl);
    padding: var(--space-lg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.series-label {
    font-family: var(--font-heading);
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--color-text-muted);
}

.series-links {
    display: flex;
    gap: var(--space-lg);
}

.series-link {
    font-family: var(--font-heading);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-accent);
    transition: color var(--transition);
}

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

.series-link-disabled {
    font-family: var(--font-heading);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-muted);
    opacity: 0.4;
}

/* ---- Footer ---- */
.site-footer {
    margin-top: auto;
    padding: var(--space-lg) 0;
    border-top: 1px solid var(--color-border);
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-brand {
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 0.9375rem;
    color: var(--color-text);
    letter-spacing: 0.02em;
}

.footer-mid {
    font-size: 0.8125rem;
    color: var(--color-text-muted);
}

.footer-mid a {
    color: var(--color-text-muted);
    text-decoration: underline;
    text-underline-offset: 2px;
    transition: color var(--transition);
}

.footer-mid a:hover {
    color: var(--color-text);
}

.footer-powered {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    opacity: 0.6;
}

.footer-powered a {
    color: var(--color-text-muted);
    text-decoration: underline;
    text-underline-offset: 2px;
    transition: color var(--transition);
}

.footer-powered a:hover {
    color: var(--color-accent);
    opacity: 1;
}

/* ---- Responsive ---- */
@media (max-width: 640px) {
    .site-header .container {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.75rem;
    }

    .footer-inner {
        flex-direction: column;
        gap: 0.25rem;
        text-align: center;
    }

    .series-nav {
        flex-direction: column;
        gap: var(--space-sm);
        text-align: center;
    }
    .nav-links a:not(.btn) { display: none; }
}

@media (min-width: 640px) {
    :root { --space-section: 5rem; }
    .hero h1 { font-size: 3.25rem; }
    .hero-sub { font-size: 1.125rem; }
}