/* ==========================================================================
   KOSMOS ERA — sanjaygidwani.net
   Design system: Dark, structured, operator-grade.
   Typography: Instrument Serif (display) + DM Sans (body)
   ========================================================================== */

/* --- CUSTOM PROPERTIES --- */
:root {
    --bg-primary:     #0a0a0c;
    --bg-secondary:   #111114;
    --bg-elevated:    #18181c;
    --bg-hover:       #1e1e24;
    
    --text-primary:   #e8e6e3;
    --text-secondary: #9b9a97;
    --text-tertiary:  #6b6a68;
    
    --accent:         #5b8def;
    --accent-muted:   rgba(91, 141, 239, 0.12);
    --accent-hover:   #7ba4f7;
    
    --signal-green:   #3ecf8e;
    
    --border:         rgba(255, 255, 255, 0.06);
    --border-hover:   rgba(255, 255, 255, 0.12);
    
    --font-display:   'Instrument Serif', Georgia, serif;
    --font-body:      'DM Sans', -apple-system, sans-serif;
    
    --max-width:      720px;
    --max-width-wide: 960px;
    --space-xs:       0.5rem;
    --space-sm:       1rem;
    --space-md:       1.5rem;
    --space-lg:       3rem;
    --space-xl:       5rem;
    --space-2xl:      8rem;
    
    --radius:         6px;
    --transition:     0.2s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

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

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

body {
    font-family: var(--font-body);
    font-weight: 400;
    line-height: 1.7;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    min-height: 100vh;
}

::selection {
    background: var(--accent-muted);
    color: var(--accent);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--accent);
    text-decoration: none;
    transition: color var(--transition);
}

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

/* --- NAVIGATION --- */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: rgba(10, 10, 12, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
}

.site-nav {
    max-width: var(--max-width-wide);
    margin: 0 auto;
    padding: 0 var(--space-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.nav-logo {
    text-decoration: none;
}

.logo-text {
    font-family: var(--font-display);
    font-size: 1.35rem;
    color: var(--text-primary);
    letter-spacing: -0.01em;
    transition: color var(--transition);
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.toggle-bar {
    width: 20px;
    height: 1.5px;
    background: var(--text-secondary);
    transition: all var(--transition);
}

.nav-links {
    list-style: none;
    display: flex;
    gap: var(--space-md);
    align-items: center;
}

.nav-links a {
    font-size: 0.85rem;
    font-weight: 400;
    color: var(--text-secondary);
    text-decoration: none;
    letter-spacing: 0.01em;
    transition: color var(--transition);
    display: flex;
    align-items: center;
    gap: 4px;
}

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

.external-icon {
    opacity: 0.4;
    transition: opacity var(--transition);
}

.nav-links a:hover .external-icon {
    opacity: 0.8;
}

/* --- MAIN --- */
main {
    padding-top: 64px;
}

/* --- HERO --- */
.hero {
    padding: var(--space-2xl) var(--space-md);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -20%;
    width: 60%;
    height: 200%;
    background: radial-gradient(ellipse at center, rgba(91, 141, 239, 0.03) 0%, transparent 70%);
    pointer-events: none;
}

.hero-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: var(--space-lg);
}

.hero-portrait {
    position: relative;
    flex-shrink: 0;
}

.portrait-img {
    width: 140px;
    height: 140px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--border-hover);
    filter: grayscale(15%);
    transition: filter var(--transition), border-color var(--transition);
}

.portrait-img:hover {
    filter: grayscale(0%);
    border-color: var(--accent-muted);
}

.portrait-glow {
    position: absolute;
    inset: -8px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(91, 141, 239, 0.08) 0%, transparent 70%);
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.4s ease;
}

.hero-portrait:hover .portrait-glow {
    opacity: 1;
}

.hero-content {
    flex: 1;
}

.hero-name {
    font-family: var(--font-display);
    font-size: 2.8rem;
    font-weight: 400;
    line-height: 1.1;
    color: var(--text-primary);
    letter-spacing: -0.02em;
    margin-bottom: var(--space-xs);
}

.hero-title {
    font-size: 0.95rem;
    font-weight: 400;
    color: var(--text-secondary);
    margin-bottom: 4px;
}

.hero-tagline {
    font-family: var(--font-display);
    font-size: 1.1rem;
    font-style: italic;
    color: var(--text-tertiary);
    margin-bottom: var(--space-sm);
}

.hero-signal {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-top: var(--space-xs);
}

.signal-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--signal-green);
    animation: pulse 2.5s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 0.4; }
    50% { opacity: 1; }
}

.hero-signal a {
    font-size: 0.85rem;
    color: var(--text-tertiary);
    transition: color var(--transition);
}

.hero-signal a:hover {
    color: var(--signal-green);
}

/* --- SECTIONS --- */
.latest-writing,
.posts-archive,
.about-page,
.default-list {
    padding: var(--space-xl) var(--space-md);
}

.section-inner,
.about-inner {
    max-width: var(--max-width);
    margin: 0 auto;
}

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

.section-header h2 {
    font-family: var(--font-display);
    font-size: 1.6rem;
    font-weight: 400;
    color: var(--text-primary);
}

.view-all {
    font-size: 0.85rem;
    color: var(--text-tertiary);
}

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

/* --- POST CARDS (Homepage) --- */
.post-card {
    border-bottom: 1px solid var(--border);
}

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

.post-link {
    display: block;
    padding: var(--space-md) 0;
    text-decoration: none;
    transition: all var(--transition);
}

.post-link:hover {
    padding-left: var(--space-sm);
}

.post-date {
    display: block;
    font-size: 0.8rem;
    color: var(--text-tertiary);
    font-variant-numeric: tabular-nums;
    margin-bottom: 6px;
}

.post-title {
    font-family: var(--font-display);
    font-size: 1.35rem;
    font-weight: 400;
    color: var(--text-primary);
    line-height: 1.3;
    margin-bottom: 6px;
    transition: color var(--transition);
}

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

.post-excerpt {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* --- ARCHIVE (Posts List Page) --- */
.archive-title {
    font-family: var(--font-display);
    font-size: 2.2rem;
    font-weight: 400;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.archive-subtitle {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: var(--space-xl);
}

.archive-year-group {
    margin-bottom: var(--space-lg);
}

.archive-year {
    font-family: var(--font-body);
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-tertiary);
    letter-spacing: 0.08em;
    text-transform: uppercase;
    margin-bottom: var(--space-sm);
    padding-bottom: var(--space-xs);
    border-bottom: 1px solid var(--border);
}

.archive-post {
    /* no extra styling needed, clean */
}

.archive-link {
    display: flex;
    align-items: baseline;
    gap: var(--space-md);
    padding: 10px 0;
    text-decoration: none;
    transition: padding-left var(--transition);
}

.archive-link:hover {
    padding-left: var(--space-xs);
}

.archive-date {
    font-size: 0.8rem;
    color: var(--text-tertiary);
    font-variant-numeric: tabular-nums;
    flex-shrink: 0;
    min-width: 52px;
}

.archive-post-title {
    font-size: 1rem;
    color: var(--text-primary);
    transition: color var(--transition);
}

.archive-link:hover .archive-post-title {
    color: var(--accent);
}

/* --- SINGLE POST --- */
.post-single {
    padding-top: var(--space-xl);
}

.post-header {
    padding: 0 var(--space-md) var(--space-lg);
    border-bottom: 1px solid var(--border);
}

.post-header-inner {
    max-width: var(--max-width);
    margin: 0 auto;
}

.post-header .post-date {
    margin-bottom: var(--space-sm);
}

.post-header .post-title {
    font-family: var(--font-display);
    font-size: 2.4rem;
    font-weight: 400;
    line-height: 1.15;
    color: var(--text-primary);
    letter-spacing: -0.015em;
}

.post-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: var(--space-sm);
}

.tag {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    background: var(--bg-elevated);
    padding: 4px 10px;
    border-radius: 20px;
    border: 1px solid var(--border);
    transition: all var(--transition);
}

.tag:hover {
    color: var(--accent);
    border-color: var(--accent-muted);
    background: rgba(91, 141, 239, 0.06);
}

/* --- POST BODY PROSE --- */
.post-body {
    padding: var(--space-lg) var(--space-md);
}

.post-body-inner {
    max-width: var(--max-width);
    margin: 0 auto;
}

.post-body-inner p {
    margin-bottom: 1.5em;
    font-size: 1.05rem;
    line-height: 1.8;
    color: var(--text-primary);
}

.post-body-inner h2 {
    font-family: var(--font-display);
    font-size: 1.6rem;
    font-weight: 400;
    color: var(--text-primary);
    margin: 2.5em 0 0.8em;
    letter-spacing: -0.01em;
}

.post-body-inner h3 {
    font-family: var(--font-body);
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 2em 0 0.6em;
}

.post-body-inner a {
    color: var(--accent);
    text-decoration: underline;
    text-decoration-color: rgba(91, 141, 239, 0.3);
    text-underline-offset: 3px;
    transition: text-decoration-color var(--transition);
}

.post-body-inner a:hover {
    text-decoration-color: var(--accent);
}

.post-body-inner blockquote {
    border-left: 2px solid var(--accent-muted);
    padding: var(--space-sm) var(--space-md);
    margin: 1.5em 0;
    color: var(--text-secondary);
    font-style: italic;
    background: var(--bg-secondary);
    border-radius: 0 var(--radius) var(--radius) 0;
}

.post-body-inner code {
    font-family: 'SF Mono', 'Fira Code', monospace;
    font-size: 0.88em;
    background: var(--bg-elevated);
    padding: 2px 6px;
    border-radius: 3px;
    color: var(--accent);
}

.post-body-inner pre {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: var(--space-md);
    overflow-x: auto;
    margin: 1.5em 0;
}

.post-body-inner pre code {
    background: none;
    padding: 0;
    color: var(--text-primary);
}

.post-body-inner ul,
.post-body-inner ol {
    margin: 1em 0 1.5em;
    padding-left: 1.5em;
}

.post-body-inner li {
    margin-bottom: 0.5em;
    font-size: 1.05rem;
    line-height: 1.7;
}

.post-body-inner hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: 2.5em 0;
}

.post-body-inner img {
    border-radius: var(--radius);
    margin: 1.5em 0;
}

.post-body-inner strong {
    font-weight: 600;
    color: var(--text-primary);
}

/* --- POST FOOTER NAV --- */
.post-footer {
    border-top: 1px solid var(--border);
    padding: var(--space-lg) var(--space-md);
}

.post-footer-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    gap: var(--space-md);
}

.post-nav {
    display: flex;
    flex-direction: column;
    gap: 4px;
    text-decoration: none;
    max-width: 48%;
    transition: all var(--transition);
}

.post-nav:hover {
    transform: translateY(-1px);
}

.post-nav-next {
    text-align: right;
    margin-left: auto;
}

.post-nav-label {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.post-nav-title {
    font-size: 0.95rem;
    color: var(--text-secondary);
    transition: color var(--transition);
}

.post-nav:hover .post-nav-title {
    color: var(--accent);
}

/* --- ABOUT PAGE --- */
.about-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding-top: var(--space-xl);
}

.about-header h1 {
    font-family: var(--font-display);
    font-size: 2.2rem;
    font-weight: 400;
    color: var(--text-primary);
    margin-bottom: var(--space-lg);
}

.about-body p {
    font-size: 1.05rem;
    line-height: 1.8;
    color: var(--text-primary);
    margin-bottom: 1.5em;
}

.about-body hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: 2.5em 0;
}

.about-body strong {
    font-weight: 600;
}

/* --- PODCAST --- */
.podcast-page {
    padding: var(--space-xl) var(--space-md);
}

.podcast-header {
    margin-bottom: var(--space-lg);
    padding-bottom: var(--space-sm);
    border-bottom: 1px solid var(--border);
}

.podcast-title {
    font-family: var(--font-display);
    font-size: 2.2rem;
    font-weight: 400;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.podcast-subtitle {
    font-size: 0.95rem;
    color: var(--text-secondary);
}

.podcast-label {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--accent);
    letter-spacing: 0.06em;
    text-transform: uppercase;
    margin-bottom: var(--space-xs);
}

/* --- TAGS GRID --- */
.tags-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: var(--space-md);
}

.tag-item {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.88rem;
    color: var(--text-secondary);
    background: var(--bg-elevated);
    padding: 8px 14px;
    border-radius: 20px;
    border: 1px solid var(--border);
    text-decoration: none;
    transition: all var(--transition);
}

.tag-item:hover {
    color: var(--accent);
    border-color: var(--accent-muted);
    background: rgba(91, 141, 239, 0.06);
}

.tag-count {
    font-size: 0.75rem;
    color: var(--text-tertiary);
}

/* --- FOOTER --- */
.site-footer {
    border-top: 1px solid var(--border);
    padding: var(--space-lg) var(--space-md);
    margin-top: var(--space-xl);
}

.footer-inner {
    max-width: var(--max-width-wide);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.footer-identity {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.footer-name {
    font-size: 0.9rem;
    color: var(--text-primary);
    font-weight: 500;
}

.footer-role {
    font-size: 0.8rem;
    color: var(--text-tertiary);
}

.footer-links {
    display: flex;
    gap: var(--space-md);
}

.footer-links a {
    font-size: 0.85rem;
    color: var(--text-tertiary);
    transition: color var(--transition);
}

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

.footer-copyright {
    width: 100%;
    text-align: center;
    margin-top: var(--space-sm);
    padding-top: var(--space-sm);
    border-top: 1px solid var(--border);
}

.footer-copyright span {
    font-size: 0.75rem;
    color: var(--text-tertiary);
}

/* --- RESPONSIVE --- */
@media (max-width: 768px) {
    :root {
        --space-xl: 3rem;
        --space-2xl: 4rem;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .nav-links {
        position: fixed;
        top: 64px;
        left: 0;
        right: 0;
        background: var(--bg-primary);
        border-bottom: 1px solid var(--border);
        flex-direction: column;
        padding: var(--space-md);
        gap: var(--space-xs);
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: all 0.3s ease;
    }
    
    .nav-links.open {
        transform: translateY(0);
        opacity: 1;
        pointer-events: all;
    }
    
    .nav-links a {
        font-size: 1rem;
        padding: 8px 0;
    }
    
    .hero-inner {
        flex-direction: column;
        text-align: center;
        gap: var(--space-md);
    }
    
    .portrait-img {
        width: 110px;
        height: 110px;
    }
    
    .hero-name {
        font-size: 2rem;
    }
    
    .hero-signal {
        justify-content: center;
    }
    
    .post-header .post-title {
        font-size: 1.8rem;
    }
    
    .archive-link {
        flex-direction: column;
        gap: 2px;
    }
    
    .post-footer-inner {
        flex-direction: column;
    }
    
    .post-nav {
        max-width: 100%;
    }
    
    .post-nav-next {
        text-align: left;
    }
    
    .footer-inner {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero-name {
        font-size: 1.7rem;
    }
    
    .post-header .post-title {
        font-size: 1.5rem;
    }
    
    .post-body-inner p,
    .post-body-inner li,
    .about-body p {
        font-size: 1rem;
    }
}

/* --- ANIMATIONS --- */
@media (prefers-reduced-motion: no-preference) {
    .hero-content,
    .hero-portrait {
        animation: fadeUp 0.6s ease both;
    }
    
    .hero-portrait {
        animation-delay: 0.1s;
    }
    
    .hero-content {
        animation-delay: 0.25s;
    }
    
    .post-card {
        animation: fadeUp 0.4s ease both;
    }
    
    .post-card:nth-child(1) { animation-delay: 0.1s; }
    .post-card:nth-child(2) { animation-delay: 0.15s; }
    .post-card:nth-child(3) { animation-delay: 0.2s; }
    .post-card:nth-child(4) { animation-delay: 0.25s; }
    .post-card:nth-child(5) { animation-delay: 0.3s; }
}

@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(12px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}