/* ==========================================================================
   Issack John — personal site
   Hand-tuned, dependency-free CSS. No runtime framework (fast by design).
   An editorial "ledger" layout: typographic rows, hairline rules, mono meta.
   ========================================================================== */

:root {
    color-scheme: light dark;

    --max-width: 50rem;

    --bg: #fbfaf8;
    --text: #15140f;
    --text-muted: #57534c;
    --text-faint: #8a847b;
    --accent: #1f3aa6;
    --accent-hover: #15287a;
    --line: rgba(20, 18, 12, 0.12);
    --frame: rgba(20, 18, 12, 0.22);
    --field: rgba(20, 18, 12, 0.03);

    --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, serif;
    --sans: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
    --mono: ui-monospace, "SF Mono", "SFMono-Regular", Menlo, Consolas, "Liberation Mono", monospace;
}

[data-theme="dark"] {
    --bg: #0c0d10;
    --text: #ededec;
    --text-muted: #a3a6ad;
    --text-faint: #6f7079;
    --accent: #93a8f0;
    --accent-hover: #b6c4f6;
    --line: rgba(255, 255, 255, 0.12);
    --frame: rgba(255, 255, 255, 0.22);
    --field: rgba(255, 255, 255, 0.035);
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --bg: #0c0d10;
        --text: #ededec;
        --text-muted: #a3a6ad;
        --text-faint: #6f7079;
        --accent: #93a8f0;
        --accent-hover: #b6c4f6;
        --line: rgba(255, 255, 255, 0.12);
        --frame: rgba(255, 255, 255, 0.22);
        --field: rgba(255, 255, 255, 0.035);
    }
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: var(--sans);
    font-size: 17px;
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

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

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

:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.skip-link {
    position: absolute;
    left: -999px;
    top: 0;
    background: var(--text);
    color: var(--bg);
    padding: 0.6rem 1rem;
    z-index: 100;
}

.skip-link:focus {
    left: 0;
}

/* Layout ------------------------------------------------------------------ */

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

main {
    padding-bottom: 5rem;
}

/* Top bar ----------------------------------------------------------------- */

.topbar {
    position: sticky;
    top: 0;
    z-index: 50;
    background: color-mix(in srgb, var(--bg) 88%, transparent);
    backdrop-filter: saturate(140%) blur(8px);
    -webkit-backdrop-filter: saturate(140%) blur(8px);
    border-bottom: 1px solid var(--line);
}

.topbar .wrap {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 58px;
}

.brand {
    font-family: var(--mono);
    font-size: 0.82rem;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    color: var(--text);
}

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

.theme-toggle {
    appearance: none;
    border: 1px solid var(--line);
    background: transparent;
    color: var(--text-muted);
    width: 36px;
    height: 36px;
    cursor: pointer;
    display: inline-grid;
    place-items: center;
    transition:
        color 0.15s ease,
        border-color 0.15s ease;
}

.theme-toggle:hover {
    color: var(--text);
    border-color: var(--frame);
}

.theme-toggle svg {
    width: 17px;
    height: 17px;
}

.theme-toggle .icon-sun {
    display: none;
}

[data-theme="dark"] .theme-toggle .icon-sun {
    display: block;
}

[data-theme="dark"] .theme-toggle .icon-moon {
    display: none;
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) .theme-toggle .icon-sun {
        display: block;
    }
    :root:not([data-theme="light"]) .theme-toggle .icon-moon {
        display: none;
    }
}

/* Hero -------------------------------------------------------------------- */

.hero {
    padding: 4.5rem 0 3.5rem;
    border-bottom: 1px solid var(--line);
}

.kicker {
    margin: 0 0 1.5rem;
    font-family: var(--mono);
    font-size: 0.78rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--text-faint);
}

.statement {
    font-family: var(--serif);
    font-weight: 500;
    font-style: italic;
    font-size: clamp(2.4rem, 7.5vw, 4.3rem);
    line-height: 1.05;
    letter-spacing: -0.02em;
    margin: 0 0 1.5rem;
    max-width: 18ch;
}

.lede {
    max-width: 34rem;
    margin: 0;
    font-size: 1.18rem;
    line-height: 1.5;
    color: var(--text-muted);
}

.evidence {
    display: flex;
    flex-wrap: wrap;
    gap: 2.5rem;
    margin-top: 2.25rem;
}

.evidence-item {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
}

.evidence-value {
    font-family: var(--serif);
    font-size: 2rem;
    line-height: 1;
    color: var(--text);
    font-variant-numeric: tabular-nums;
}

.evidence-label {
    font-family: var(--mono);
    font-size: 0.72rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-faint);
}

.signal {
    padding-top: 0.9rem;
    border-top: 1px solid var(--line);
}

.signal-label {
    display: block;
    margin-bottom: 0.25rem;
    font-family: var(--mono);
    font-size: 0.72rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-faint);
}

.signal-value {
    font-size: 0.95rem;
    color: var(--text-muted);
}

.links {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    margin-top: 2.25rem;
    font-family: var(--mono);
    font-size: 0.85rem;
    letter-spacing: 0.02em;
}

.links a {
    color: var(--text-muted);
    padding-bottom: 1px;
    border-bottom: 1px solid transparent;
}

.links a:hover {
    color: var(--accent);
    border-color: var(--line);
}

.cta {
    display: inline-block;
    margin-top: 2.25rem;
    font-family: var(--mono);
    font-size: 0.85rem;
    letter-spacing: 0.02em;
    color: var(--text);
    border-bottom: 1px solid var(--frame);
    padding-bottom: 2px;
}

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

/* Block (numbered index section) ------------------------------------------ */

.block {
    display: grid;
    grid-template-columns: 8rem 1fr;
    gap: 1.5rem 2.5rem;
    padding: 3rem 0;
    border-bottom: 1px solid var(--line);
}

.block-index {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    font-family: var(--mono);
}

.block-index .num {
    font-size: 0.8rem;
    color: var(--text-faint);
    letter-spacing: 0.05em;
}

.block-label {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text);
}

.block-body {
    min-width: 0;
}

.block-lead {
    margin-top: 0;
    font-size: 1.18rem;
    line-height: 1.55;
    color: var(--text);
}

.block-body p {
    color: var(--text-muted);
    margin: 0 0 1rem;
}

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

.block-note {
    margin: 0 0 1.5rem !important;
    color: var(--text-faint) !important;
    font-size: 0.95rem;
}

.meta {
    font-family: var(--mono);
    font-size: 0.82rem;
    color: var(--text-faint) !important;
    letter-spacing: 0.01em;
}

/* Ledger rows (benchmarks / history / writing / watching) ----------------- */

.ledger {
    display: flex;
    flex-direction: column;
}

.ledger .item,
.ledger .post {
    display: block;
    padding: 0.95rem 0;
    border-top: 1px solid var(--line);
    background: none;
    border-radius: 0;
    box-shadow: none;
}

.ledger .item:first-child,
.ledger .post:first-child {
    border-top: none;
}

.item-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.item-title {
    font-weight: 600;
    color: var(--text);
    transition: color 0.12s ease;
}

.ledger .item:hover .item-title {
    color: var(--accent);
}

.item-date {
    font-family: var(--mono);
    font-size: 0.78rem;
    color: var(--text-faint);
    white-space: nowrap;
    letter-spacing: 0.02em;
}

.item-desc {
    margin: 0.3rem 0 0;
    font-size: 0.92rem;
    color: var(--text-muted);
}

.item-head .arrow {
    margin-left: auto;
    flex-shrink: 0;
}

.item .arrow {
    color: var(--text-faint);
    transition:
        transform 0.15s ease,
        color 0.12s ease;
    display: inline-block;
}

.ledger .item:hover .arrow {
    color: var(--accent);
    transform: translateX(4px);
}

/* Writing rows reuse .post markup from JS --------------------------------- */

.post h3 {
    margin: 0 0 0.3rem;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
}

.post p {
    margin: 0 0 0.5rem;
    font-size: 0.92rem;
    color: var(--text-muted);
}

.post-foot {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 1rem;
}

.post-foot a {
    font-family: var(--mono);
    font-size: 0.8rem;
}

.post-foot time {
    font-family: var(--mono);
    font-size: 0.78rem;
    color: var(--text-faint);
}

/* Footer ------------------------------------------------------------------ */

.site-footer {
    padding: 2.5rem 0 3.5rem;
    color: var(--text-faint);
    font-family: var(--mono);
    font-size: 0.8rem;
    letter-spacing: 0.02em;
}

/* Blog index + article ---------------------------------------------------- */

.page-header {
    padding: 4.5rem 0 2.5rem;
    border-bottom: 1px solid var(--line);
}

.page-header .kicker {
    margin-bottom: 1rem;
}

.page-title {
    font-family: var(--serif);
    font-weight: 500;
    font-style: italic;
    font-size: clamp(2.2rem, 6vw, 3.4rem);
    line-height: 1.05;
    letter-spacing: -0.02em;
    margin: 0 0 1rem;
}

.page-intro {
    max-width: 34rem;
    margin: 0;
    color: var(--text-muted);
    font-size: 1.1rem;
    line-height: 1.5;
}

.post-list {
    display: flex;
    flex-direction: column;
    padding: 1.5rem 0 0;
}

.article {
    padding: 3.5rem 0 0;
}

.article-meta {
    font-family: var(--mono);
    font-size: 0.8rem;
    letter-spacing: 0.04em;
    color: var(--text-faint);
    margin: 0 0 1.25rem;
}

.article-title {
    font-family: var(--serif);
    font-weight: 500;
    font-size: clamp(2rem, 5.5vw, 3rem);
    line-height: 1.08;
    letter-spacing: -0.02em;
    margin: 0 0 2.25rem;
    max-width: 20ch;
}

.prose {
    max-width: 38rem;
    font-size: 1.06rem;
    line-height: 1.7;
}

.prose p {
    margin: 0 0 1.3rem;
    color: var(--text);
}

.prose h2 {
    font-family: var(--serif);
    font-weight: 600;
    font-size: 1.4rem;
    letter-spacing: -0.01em;
    margin: 2.6rem 0 1rem;
}

.prose ul {
    margin: 0 0 1.3rem;
    padding-left: 1.2rem;
}

.prose li {
    margin: 0 0 0.5rem;
}

.prose blockquote {
    margin: 1.8rem 0;
    padding-left: 1.3rem;
    border-left: 2px solid var(--frame);
    color: var(--text-muted);
    font-style: italic;
}

.prose a {
    border-bottom: 1px solid var(--frame);
}

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

.prose code {
    font-family: var(--mono);
    font-size: 0.88em;
    background: var(--field);
    padding: 0.1em 0.35em;
    border: 1px solid var(--line);
}

.prose pre {
    display: block;
    padding: 1.2rem;
    background: var(--field);
    border: 1px solid var(--line);
    overflow-x: auto;
    margin: 1.8rem 0;
}

.prose pre code {
    padding: 0;
    background: none;
    border: none;
    font-size: 0.84em;
    line-height: 1.5;
}

.prose strong {
    font-weight: 600;
}

.prose figure {
    margin: 1.8rem 0;
}

.prose figure img {
    display: block;
    width: 100%;
    height: auto;
    border: 1px solid var(--frame);
}

.prose figcaption {
    margin-top: 0.5rem;
    font-family: var(--mono);
    font-size: 0.74rem;
    letter-spacing: 0.02em;
    color: var(--text-faint);
}

.back-link {
    display: inline-block;
    font-family: var(--mono);
    font-size: 0.8rem;
    letter-spacing: 0.02em;
    color: var(--text-faint);
}

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

.article-foot {
    margin-top: 3.5rem;
    padding-top: 1.75rem;
    border-top: 1px solid var(--line);
}

/* Reveal-on-scroll animation ---------------------------------------------- */

.reveal {
    opacity: 0;
    transform: translateY(12px);
    transition:
        opacity 0.5s ease,
        transform 0.5s ease;
}

.reveal.is-visible {
    opacity: 1;
    transform: none;
}

/* Responsive -------------------------------------------------------------- */

@media (max-width: 680px) {
    .block {
        grid-template-columns: 1fr;
        gap: 0.75rem;
    }

    .block-index {
        flex-direction: row;
        gap: 0.75rem;
        align-items: baseline;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }
    *,
    *::before,
    *::after {
        animation-duration: 0.001ms !important;
        transition-duration: 0.001ms !important;
    }
    .reveal {
        opacity: 1;
        transform: none;
    }
}