/* ============================================================
   miris.tech -- Engineering Journal
   Swiss-typographic editorial. IBM Plex family unification.
   Palette: #fafaf8 #161616 #0f62fe #f4f4f4 #525252 #da1e28 #e0e0e0
   ============================================================ */

:root {
    --paper:        #fafaf8;
    --carbon:       #161616;
    --ibm-blue:     #0f62fe;
    --code-bg:      #f4f4f4;
    --support:      #525252;
    --alert:        #da1e28;
    --rule:         #e0e0e0;

    --col:          720px;
    --col-pad:      1.5rem;

    --font-sans:    "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
    --font-serif:   "IBM Plex Serif", Georgia, "Times New Roman", serif;
    --font-mono:    "IBM Plex Mono", "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

html {
    scroll-behavior: smooth;
    background: var(--paper);
}

body {
    margin: 0;
    background: var(--paper);
    color: var(--carbon);
    font-family: var(--font-serif);
    font-size: 1.05rem;
    line-height: 1.85;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

::selection {
    background: var(--ibm-blue);
    color: var(--paper);
}

a {
    color: var(--ibm-blue);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 200ms ease, color 200ms ease;
}

a:hover {
    border-bottom-color: var(--ibm-blue);
}

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

/* ----------------------------------------------------------------
   Site header
---------------------------------------------------------------- */

.site-header {
    position: sticky;
    top: 0;
    z-index: 30;
    background: rgba(250, 250, 248, 0.92);
    backdrop-filter: saturate(140%) blur(8px);
    -webkit-backdrop-filter: saturate(140%) blur(8px);
    border-bottom: 1px solid var(--rule);
}

.site-header__inner {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0.85rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
    font-family: var(--font-sans);
}

.site-header__brand {
    display: inline-flex;
    align-items: baseline;
    gap: 0.5rem;
    color: var(--carbon);
    font-weight: 600;
    font-size: 0.95rem;
    border-bottom: none;
}

.brand-mark {
    display: inline-block;
    padding: 0.1rem 0.4rem;
    background: var(--carbon);
    color: var(--paper);
    font-family: var(--font-mono);
    font-weight: 500;
    font-size: 0.78rem;
    letter-spacing: 0.02em;
    border-radius: 2px;
    transform: translateY(-1px);
}

.brand-name {
    letter-spacing: 0.005em;
}

.site-header__nav {
    display: flex;
    gap: 1.4rem;
    font-size: 0.85rem;
    font-weight: 500;
    letter-spacing: 0.02em;
}

.site-header__nav a {
    color: var(--support);
    border-bottom: 1px solid transparent;
    padding-bottom: 2px;
}

.site-header__nav a:hover {
    color: var(--carbon);
    border-bottom-color: var(--carbon);
}

@media (max-width: 720px) {
    .site-header__nav { display: none; }
}

/* ----------------------------------------------------------------
   Hero (with grid paper background)
---------------------------------------------------------------- */

.hero {
    position: relative;
    overflow: hidden;
    border-bottom: 1px solid var(--rule);
    padding: clamp(4rem, 10vw, 8rem) 1.5rem clamp(3rem, 7vw, 5rem);
}

.hero__grid {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(0, 0, 0, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 0, 0, 0.03) 1px, transparent 1px);
    background-size: 20px 20px;
    background-position: -1px -1px;
    pointer-events: none;
    mask-image: radial-gradient(ellipse at 50% 60%, #000 55%, transparent 100%);
    -webkit-mask-image: radial-gradient(ellipse at 50% 60%, #000 55%, transparent 100%);
}

.hero__inner {
    position: relative;
    max-width: var(--col);
    margin: 0 auto;
    padding: 0 var(--col-pad);
}

.hero__meta {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--support);
    margin-bottom: 1.5rem;
}

.hero__title {
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: clamp(1.9rem, 4.4vw, 3.2rem);
    line-height: 1.12;
    letter-spacing: -0.015em;
    margin: 0 0 1.25rem;
    color: var(--carbon);
}

.hero__lede {
    font-family: var(--font-serif);
    font-size: clamp(1.05rem, 1.6vw, 1.25rem);
    line-height: 1.7;
    color: var(--support);
    margin: 0 0 2.5rem;
    max-width: 38em;
}

.hero__divider {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin: 0 0 2rem;
    color: var(--support);
}

.hero__divider span {
    flex: 1;
    height: 1px;
    background: var(--rule);
}

.hero__divider em {
    font-family: var(--font-mono);
    font-style: normal;
    font-size: 0.75rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
}

.hero__masthead {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.25rem 2rem;
    margin: 0;
    padding: 1rem 0 0;
    border-top: 1px solid var(--rule);
}

.hero__masthead > div { margin: 0; }

.hero__masthead dt {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--support);
    margin-bottom: 0.25rem;
}

.hero__masthead dd {
    margin: 0;
    font-family: var(--font-sans);
    font-size: 0.92rem;
    font-weight: 500;
    color: var(--carbon);
    line-height: 1.4;
}

@media (max-width: 720px) {
    .hero__masthead { grid-template-columns: repeat(2, 1fr); }
}

/* ----------------------------------------------------------------
   Layout: content column + floating TOC
---------------------------------------------------------------- */

.layout {
    position: relative;
    max-width: 1280px;
    margin: 0 auto;
    padding: clamp(2rem, 5vw, 4rem) 1.5rem clamp(3rem, 6vw, 5rem);
}

.content {
    max-width: var(--col);
    margin: 0 auto;
    padding: 0 var(--col-pad);
}

/* Floating TOC: only on wide screens */
.toc {
    display: none;
}

@media (min-width: 1200px) {
    .layout {
        display: grid;
        grid-template-columns: 1fr minmax(0, calc(var(--col) + var(--col-pad) * 2)) 1fr;
        column-gap: 2rem;
        align-items: start;
    }

    .content {
        grid-column: 2 / 3;
        max-width: 100%;
        padding: 0 var(--col-pad);
    }

    .toc {
        display: block;
        grid-column: 3 / 4;
        position: sticky;
        top: 5rem;
        align-self: start;
        max-width: 240px;
        padding: 0.25rem 0 0 1rem;
        border-left: 1px solid var(--rule);
        font-family: var(--font-sans);
    }
}

.toc__heading {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--support);
    margin-bottom: 0.85rem;
}

.toc__list {
    list-style: none;
    padding: 0;
    margin: 0;
    counter-reset: toc;
}

.toc__list li {
    counter-increment: toc;
    margin-bottom: 0.55rem;
    line-height: 1.4;
}

.toc__list a {
    display: block;
    padding: 0.25rem 0 0.25rem 0.85rem;
    margin-left: -2px;
    border-left: 2px solid transparent;
    color: var(--support);
    font-size: 0.85rem;
    font-weight: 500;
    letter-spacing: 0.005em;
    transition: color 200ms ease, border-color 200ms ease;
}

.toc__list a::before {
    content: counter(toc, decimal-leading-zero) "  ";
    color: var(--rule);
    font-family: var(--font-mono);
    font-size: 0.72rem;
    letter-spacing: 0.06em;
}

.toc__list a:hover {
    color: var(--carbon);
    border-left-color: var(--rule);
}

.toc__list a.is-active {
    color: var(--carbon);
    border-left-color: var(--ibm-blue);
}

/* ----------------------------------------------------------------
   Articles
---------------------------------------------------------------- */

.article {
    position: relative;
    padding: clamp(2.5rem, 5vw, 4rem) 0 clamp(2rem, 4vw, 3rem);
}

.article + .separator,
.colophon + .separator {
    margin: 0;
}

.article__num {
    position: absolute;
    top: 1.25rem;
    left: -0.5rem;
    font-family: var(--font-sans);
    font-weight: 300;
    font-size: clamp(3rem, 6vw, 5rem);
    line-height: 1;
    color: var(--rule);
    letter-spacing: -0.03em;
    z-index: 0;
    pointer-events: none;
    user-select: none;
}

@media (max-width: 720px) {
    .article__num {
        font-size: 2.5rem;
        top: 0.5rem;
        left: 0;
        opacity: 0.6;
    }
}

.article__header {
    position: relative;
    z-index: 1;
    margin-bottom: 2rem;
}

.article__category {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--ibm-blue);
    margin-bottom: 0.85rem;
    display: inline-block;
}

.article__title {
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: clamp(1.5rem, 3vw, 2.5rem);
    line-height: 1.18;
    letter-spacing: -0.012em;
    margin: 0 0 0.75rem;
    color: var(--carbon);
}

.article__dek {
    font-family: var(--font-serif);
    font-style: italic;
    font-size: 1.1rem;
    line-height: 1.55;
    color: var(--support);
    margin: 0 0 1.25rem;
    max-width: 36em;
}

.article__meta {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem 1.4rem;
    font-family: var(--font-mono);
    font-size: 0.74rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--support);
}

.article__meta li {
    position: relative;
}

.article__meta li + li::before {
    content: "";
    position: absolute;
    left: -0.85rem;
    top: 50%;
    width: 4px;
    height: 4px;
    background: var(--rule);
    transform: translateY(-50%);
    border-radius: 50%;
}

.article__body {
    position: relative;
    z-index: 1;
}

.article__body > p {
    margin: 0 0 1.25rem;
}

.article__body h3 {
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 1.25rem;
    line-height: 1.3;
    letter-spacing: -0.005em;
    color: var(--carbon);
    margin: 2.4rem 0 1rem;
    padding-top: 0.5rem;
    border-top: 1px solid var(--rule);
}

.article__body h4 {
    font-family: var(--font-sans);
    font-weight: 500;
    font-size: 1.05rem;
    color: var(--carbon);
    margin: 2rem 0 0.6rem;
}

.article__body code {
    font-family: var(--font-mono);
    font-size: 0.88em;
    background: var(--code-bg);
    border: 1px solid var(--rule);
    border-radius: 3px;
    padding: 0.05rem 0.35rem;
    color: var(--carbon);
}

.article__body sup.fn {
    color: var(--ibm-blue);
    font-family: var(--font-mono);
    font-size: 0.7em;
    margin-left: 0.1em;
}

/* Drop cap on first paragraph */
.dropcap::first-letter {
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 3.6em;
    float: left;
    line-height: 0.9;
    margin: 0.1em 0.12em 0 -0.04em;
    color: var(--carbon);
}

/* Numbered lists */
.numbered {
    counter-reset: num;
    list-style: none;
    padding: 0;
    margin: 0 0 1.5rem;
}

.numbered li {
    counter-increment: num;
    position: relative;
    padding-left: 2.4rem;
    margin-bottom: 0.6rem;
    line-height: 1.7;
}

.numbered li::before {
    content: counter(num, decimal-leading-zero);
    position: absolute;
    left: 0;
    top: 0.05em;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--ibm-blue);
    letter-spacing: 0.04em;
    width: 2rem;
    border-right: 1px solid var(--rule);
    padding-right: 0.5rem;
    text-align: right;
    line-height: 1.7;
}

/* Pull quote */
.pullquote {
    margin: 2rem 0;
    padding: 1.25rem 0 1.25rem 1.5rem;
    border-left: 3px solid var(--ibm-blue);
    background: linear-gradient(90deg, rgba(15, 98, 254, 0.04), transparent 70%);
}

.pullquote p {
    margin: 0;
    font-family: var(--font-serif);
    font-style: italic;
    font-size: 1.18rem;
    line-height: 1.55;
    color: var(--carbon);
    letter-spacing: -0.005em;
}

/* Article rule + footnote */
.article__rule {
    border: none;
    border-top: 1px solid var(--rule);
    margin: 2.5rem 0 1.5rem;
}

.footnote {
    font-family: var(--font-serif);
    font-size: 0.88rem;
    line-height: 1.65;
    color: var(--support);
    margin: 0;
}

.footnote sup {
    color: var(--ibm-blue);
    font-family: var(--font-mono);
    margin-right: 0.25em;
}

/* Inline keyboard / hex chip */
.kbd {
    font-family: var(--font-mono);
    font-size: 0.85em;
    background: var(--code-bg);
    border: 1px solid var(--rule);
    border-bottom-width: 2px;
    border-radius: 3px;
    padding: 0.05rem 0.4rem;
    color: var(--carbon);
}

/* ----------------------------------------------------------------
   Code blocks
---------------------------------------------------------------- */

.codeblock {
    margin: 1.75rem 0 1.75rem;
    border-radius: 4px;
    overflow: hidden;
    box-shadow: 0 1px 0 rgba(0, 0, 0, 0.02);
}

.codeblock__bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--rule);
    padding: 4px 12px;
    border-radius: 4px 4px 0 0;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--support);
    letter-spacing: 0.04em;
}

.codeblock__lang {
    text-transform: uppercase;
    font-weight: 500;
    color: var(--carbon);
    letter-spacing: 0.1em;
}

.codeblock__file {
    font-style: normal;
    color: var(--support);
}

.codeblock pre {
    margin: 0;
    background: var(--code-bg);
    border: 1px solid var(--rule);
    border-top: none;
    border-radius: 0 0 4px 4px;
    padding: 1rem;
    overflow-x: auto;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    line-height: 1.65;
    color: var(--carbon);
}

.codeblock pre code {
    font-family: var(--font-mono);
    background: none;
    border: none;
    padding: 0;
    font-size: 1em;
}

/* Pseudo syntax tokens */
.tok-kw  { color: #6f42c1; font-weight: 500; }
.tok-fn  { color: var(--ibm-blue); }
.tok-num { color: var(--alert); }
.tok-str { color: #0f7a3f; }
.tok-com { color: var(--support); font-style: italic; }

/* ----------------------------------------------------------------
   Section separators
---------------------------------------------------------------- */

.separator {
    position: relative;
    max-width: var(--col);
    margin: 0.5rem auto;
    padding: 0 var(--col-pad);
    text-align: center;
}

.separator::before {
    content: "";
    display: block;
    height: 1px;
    background: var(--rule);
    margin: 0 auto;
}

.separator__num {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: var(--paper);
    padding: 0 0.85rem;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--support);
    letter-spacing: 0.16em;
}

/* ----------------------------------------------------------------
   Colophon
---------------------------------------------------------------- */

.colophon {
    position: relative;
    padding: clamp(2.5rem, 5vw, 4rem) 0 clamp(2.5rem, 5vw, 4rem);
}

.colophon .article__num {
    font-size: clamp(2.5rem, 5vw, 4rem);
}

.colophon__grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.25rem 2rem;
    margin: 1.5rem 0 2rem;
    padding: 1.25rem 0;
    border-top: 1px solid var(--rule);
    border-bottom: 1px solid var(--rule);
}

.colophon__cell { margin: 0; }

.colophon__label {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--support);
    margin-bottom: 0.35rem;
}

.colophon__value {
    font-family: var(--font-serif);
    font-size: 0.98rem;
    line-height: 1.55;
    color: var(--carbon);
}

.colophon__signoff {
    font-family: var(--font-sans);
    font-style: normal;
    font-size: 0.95rem;
    color: var(--support);
    margin: 0;
}

@media (max-width: 720px) {
    .colophon__grid { grid-template-columns: 1fr; }
}

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

.site-footer {
    border-top: 1px solid var(--rule);
    background: var(--paper);
    padding: 2.5rem 1.5rem 3rem;
    font-family: var(--font-sans);
}

.site-footer__inner {
    max-width: 1280px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 1rem 2rem;
    align-items: center;
}

.site-footer__brand {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.85rem;
    color: var(--carbon);
    font-weight: 500;
}

.site-footer__links {
    display: flex;
    gap: 1.4rem;
    font-size: 0.82rem;
}

.site-footer__links a {
    color: var(--support);
    border-bottom: 1px solid transparent;
    padding-bottom: 1px;
}

.site-footer__links a:hover {
    color: var(--carbon);
    border-bottom-color: var(--carbon);
}

.site-footer__legal {
    grid-column: 1 / -1;
    border-top: 1px solid var(--rule);
    padding-top: 1.25rem;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    letter-spacing: 0.04em;
    color: var(--support);
}

@media (max-width: 720px) {
    .site-footer__inner {
        grid-template-columns: 1fr;
    }
    .site-footer__links {
        flex-wrap: wrap;
    }
}

/* ----------------------------------------------------------------
   Back-to-top button
---------------------------------------------------------------- */

.totop {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 1px solid var(--rule);
    background: var(--paper);
    color: var(--carbon);
    font-family: var(--font-sans);
    font-size: 1.05rem;
    line-height: 1;
    cursor: pointer;
    opacity: 0;
    pointer-events: none;
    transform: translateY(8px);
    transition: opacity 250ms ease, transform 250ms ease, background 200ms ease;
    z-index: 40;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
}

.totop:hover {
    background: var(--carbon);
    color: var(--paper);
    border-color: var(--carbon);
}

.totop.is-visible {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
}

/* ----------------------------------------------------------------
   Fade-reveal animation (500ms)
---------------------------------------------------------------- */

[data-reveal] {
    opacity: 0;
    transform: translateY(14px);
    transition: opacity 500ms ease, transform 500ms ease;
    will-change: opacity, transform;
}

[data-reveal].is-revealed {
    opacity: 1;
    transform: translateY(0);
}

/* Respect reduced motion */
@media (prefers-reduced-motion: reduce) {
    [data-reveal] {
        opacity: 1;
        transform: none;
        transition: none;
    }
    html { scroll-behavior: auto; }
}