/* ═══════════════════════════════════════════════════
   mlab engineering notes (/engineering)
   Index, article layout and every block an article can
   use. Builds on mlab-editorial.css (report rail, kv,
   eyebrow). Behaviour: /assets/js/mlab-engineering.js
═══════════════════════════════════════════════════ */

.eng-root {
    --eng-ink: var(--card-foreground, #111827);
    --eng-muted: var(--mlab-text-secondary, #6b7280);
    --eng-faint: color-mix(in srgb, var(--eng-ink) 38%, var(--eng-surface));
    --eng-line: var(--mlab-edit-hairline);
    --eng-line-strong: var(--mlab-edit-hairline-strong);
    --eng-surface: var(--card, #ffffff);
    --eng-sunken: color-mix(in srgb, var(--eng-ink) 3%, var(--eng-surface));
    --eng-grid: color-mix(in srgb, var(--eng-ink) 8%, var(--eng-surface));
    --eng-accent: #d97706;
    --eng-accent-soft: rgba(217, 119, 6, .10);
    --eng-mono: var(--mlab-edit-mono);
    --eng-serif: var(--mlab-font-sans, 'Inter', system-ui, sans-serif);
    --eng-math: Georgia, 'Times New Roman', serif;

    /* Categorical: validated all-pairs (CVD + normal vision) on both surfaces.
       Slot 1 is always mlab. Never cycle past slot 3. */
    --eng-s1: #d97706;
    --eng-s2: #2a78d6;
    --eng-s3: #c2416f;

    /* Status: outcomes, always shipped with a label. */
    --eng-good: #16a34a;
    --eng-bad: #dc2626;
    --eng-neutral: color-mix(in srgb, var(--eng-ink) 22%, var(--eng-surface));
    --eng-warn: #f59e0b;
    --eng-faint-fill: color-mix(in srgb, var(--eng-ink) 10%, var(--eng-surface));

    /* Sequential (heatmap): one hue, low to high. */
    --eng-seq-lo: #fef7e6;
    --eng-seq-hi: #a8460a;
    --eng-seq-on-hi: #ffffff;

    /* Code */
    --eng-code-bg: #fafaf9;
    --eng-code-kw: #9333ea;
    --eng-code-str: #15803d;
    --eng-code-num: #c2410c;
    --eng-code-com: #78716c;
    --eng-code-fn: #1d4ed8;
    --eng-code-ty: #0f766e;
    --eng-code-hl: rgba(217, 119, 6, .09);

    --eng-ease: cubic-bezier(.2, .8, .2, 1);
}

html[data-bs-theme=dark] .eng-root {
    --eng-s2: #3987e5;
    --eng-s3: #d55181;
    --eng-good: #22c55e;
    --eng-bad: #ef4444;
    --eng-accent-soft: rgba(217, 119, 6, .16);
    --eng-seq-lo: #2a1d0b;
    --eng-seq-hi: #fbbf24;
    --eng-seq-on-hi: #1f1400;
    --eng-code-bg: #0c0d0f;
    --eng-code-kw: #c084fc;
    --eng-code-str: #86efac;
    --eng-code-num: #fdba74;
    --eng-code-com: #8b9099;
    --eng-code-fn: #93c5fd;
    --eng-code-ty: #5eead4;
    --eng-code-hl: rgba(217, 119, 6, .14);
}

.eng-mono { font-family: var(--eng-mono); }
.eng-s1 { --eng-c: var(--eng-s1); }
.eng-s2 { --eng-c: var(--eng-s2); }
.eng-s3 { --eng-c: var(--eng-s3); }

/* ─── Reading progress (top of viewport) ─── */
.eng-progress {
    position: fixed; inset: 0 0 auto 0; height: 2px; z-index: 1100;
    pointer-events: none;
}
.eng-progress span {
    display: block; height: 100%; width: 100%;
    background: var(--eng-accent);
    transform-origin: 0 50%;
    transform: scaleX(var(--p, 0));
}

/* ═══ Index ═══════════════════════════════════════════ */
.eng-index-hero {
    position: relative;
    overflow: hidden;
    border: 1px solid var(--eng-line);
    border-radius: 20px;
    background: var(--eng-surface);
    padding: 2.6rem 2.4rem 1.6rem;
    margin-top: 1rem;
}
.eng-index-grid {
    position: absolute; inset: 0;
    background-image:
        linear-gradient(var(--eng-line) 1px, transparent 1px),
        linear-gradient(90deg, var(--eng-line) 1px, transparent 1px);
    background-size: 32px 32px;
    mask-image: radial-gradient(ellipse 70% 90% at 100% 0%, #000 0%, transparent 70%);
    -webkit-mask-image: radial-gradient(ellipse 70% 90% at 100% 0%, #000 0%, transparent 70%);
    pointer-events: none;
}
.eng-index-hero::after {
    content: ""; position: absolute; right: -120px; top: -160px;
    width: 420px; height: 420px; border-radius: 50%;
    background: radial-gradient(circle, rgba(217, 119, 6, .16), transparent 65%);
    pointer-events: none;
}
.eng-index-hero-inner { position: relative; z-index: 1; }
.eng-eyebrow { display: flex; align-items: center; gap: .5rem; }
.eng-eyebrow a { display: inline-flex; align-items: center; gap: .35rem; text-decoration: none; transition: color .15s ease; }
.eng-eyebrow a:hover { color: var(--eng-ink); }
.eng-eyebrow :is(i, svg) { width: 13px; height: 13px; }
.eng-eyebrow-sep { opacity: .5; }
.eng-eyebrow-dot {
    width: 7px; height: 7px; border-radius: 50%;
    background: var(--eng-accent);
    box-shadow: 0 0 0 4px var(--eng-accent-soft);
}
.eng-index-title {
    font-family: var(--eng-serif);
    font-size: clamp(2.1rem, 4.2vw, 3.2rem);
    font-weight: 600;
    line-height: 1.06;
    letter-spacing: -.03em;
    color: var(--eng-ink);
    margin: 0 0 1rem;
}
.eng-index-lead { max-width: 60ch; color: var(--eng-muted); font-size: 1.02rem; line-height: 1.7; margin-bottom: 1.6rem; }
.eng-index-kv { max-width: 760px; }

.eng-rules {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    margin: 1.25rem 0 2.5rem;
    border: 1px solid var(--eng-line);
    border-radius: 16px;
    background: var(--eng-surface);
}
.eng-rule { padding: 1.4rem 1.5rem; }
.eng-rule + .eng-rule { border-left: 1px solid var(--eng-line); }
.eng-rule-num { font-family: var(--eng-mono); font-size: .72rem; color: var(--eng-accent); font-weight: 600; }
.eng-rule-title { font-size: 1rem; font-weight: 600; color: var(--eng-ink); margin: .55rem 0 .4rem; }
.eng-rule p { color: var(--eng-muted); font-size: .88rem; line-height: 1.6; margin: 0; }

.eng-list-head {
    display: flex; align-items: baseline; gap: .8rem;
    padding-bottom: .8rem; border-bottom: 1px solid var(--eng-line-strong);
}
.eng-list-head .mlab-report-section-num { margin-left: auto; }
.eng-entry {
    display: grid;
    grid-template-columns: 150px minmax(0, 1fr) auto;
    gap: 1.5rem;
    padding: 1.6rem .4rem;
    border-bottom: 1px solid var(--eng-line);
    color: inherit;
    text-decoration: none;
    position: relative;
    transition: background .2s ease;
}
.eng-entry::before {
    content: ""; position: absolute; left: 0; top: 1.6rem; bottom: 1.6rem; width: 2px;
    background: var(--eng-accent); border-radius: 2px;
    transform: scaleY(0); transition: transform .3s var(--eng-ease);
}
.eng-entry:hover { background: var(--eng-sunken); color: inherit; }
.eng-entry:hover::before { transform: scaleY(1); }
.eng-entry-meta { display: flex; flex-direction: column; gap: .35rem; font-family: var(--eng-mono); font-size: .74rem; color: var(--eng-muted); padding-left: .6rem; }
.eng-entry-num { color: var(--eng-accent); font-weight: 600; }
.eng-entry-title {
    font-family: var(--eng-serif); font-weight: 600; font-size: 1.35rem; letter-spacing: -.015em; line-height: 1.25;
    color: var(--eng-ink); margin: 0 0 .5rem;
}
.eng-entry-summary { color: var(--eng-muted); font-size: .92rem; line-height: 1.65; margin: 0 0 .8rem; max-width: 68ch; }
.eng-entry-tags { display: flex; flex-wrap: wrap; gap: .35rem; }
.eng-entry-side {
    display: flex; align-items: flex-start; gap: .6rem; white-space: nowrap;
    font-family: var(--eng-mono); font-size: .74rem; color: var(--eng-muted);
}
.eng-entry-side :is(i, svg) { width: 18px; height: 18px; color: var(--eng-ink); transition: transform .25s var(--eng-ease); }
.eng-entry:hover .eng-entry-side :is(i, svg) { transform: translate(3px, -3px); color: var(--eng-accent); }

.eng-tag {
    display: inline-flex; align-items: center;
    font-family: var(--eng-mono); font-size: .68rem;
    padding: .18rem .5rem; border-radius: 999px;
    border: 1px solid var(--eng-line); color: var(--eng-muted);
    background: var(--eng-surface);
}
.eng-badge-sample {
    display: inline-flex; align-items: center; gap: .3rem;
    font-family: var(--eng-mono); font-size: .68rem; font-weight: 600;
    padding: .18rem .55rem; border-radius: 999px;
    color: #b45309; background: rgba(217, 119, 6, .10); border: 1px solid rgba(217, 119, 6, .24);
}
html[data-bs-theme=dark] .eng-badge-sample { color: #fcd34d; background: rgba(245, 158, 11, .14); border-color: rgba(245, 158, 11, .30); }
.eng-badge-sample :is(i, svg) { width: 12px; height: 12px; }

/* ─── Index: search + tag filter ─── */
.eng-filter { display: flex; flex-wrap: wrap; align-items: center; gap: .75rem 1rem; padding: 1rem 0; border-bottom: 1px solid var(--eng-line); }
.eng-search {
    position: relative; display: flex; align-items: center; flex: 1 1 280px; max-width: 420px; margin: 0;
    height: 38px; padding: 0 .55rem 0 .75rem; gap: .5rem;
    border: 1px solid var(--eng-line-strong); border-radius: 10px; background: var(--eng-surface);
    transition: border-color .15s ease, box-shadow .15s ease;
}
.eng-search:focus-within { border-color: var(--eng-accent); box-shadow: 0 0 0 3px var(--eng-accent-soft); }
.eng-search > :is(i, svg) { width: 16px; height: 16px; color: var(--eng-muted); flex: 0 0 auto; }
.eng-search input {
    flex: 1 1 auto; min-width: 0; height: 100%; border: 0; outline: 0; background: transparent;
    font-size: .88rem; color: var(--eng-ink);
}
.eng-search input::placeholder { color: var(--eng-faint); }
/* The wrapper carries the focus ring; the site-wide input ring would double it. */
.eng-search input:is(:focus, :focus-visible) { outline: none !important; box-shadow: none !important; border: 0 !important; }
.eng-search input::-webkit-search-cancel-button { -webkit-appearance: none; }
.eng-search kbd {
    font-family: var(--eng-mono); font-size: .66rem; color: var(--eng-muted); line-height: 1;
    padding: .2rem .4rem; border-radius: 5px; border: 1px solid var(--eng-line-strong); background: var(--eng-sunken);
    box-shadow: none;
}
.eng-search:focus-within kbd { opacity: 0; }
.eng-filter-chips { display: flex; flex-wrap: wrap; gap: .4rem; }
.eng-filter-chip {
    display: inline-flex; align-items: center; gap: .4rem;
    font-family: var(--eng-mono); font-size: .72rem; color: var(--eng-muted);
    padding: .3rem .6rem; border-radius: 999px; border: 1px solid var(--eng-line); background: var(--eng-surface);
    cursor: pointer; transition: color .15s ease, border-color .15s ease, background .15s ease;
}
.eng-filter-chip span { font-size: .64rem; color: var(--eng-faint); }
.eng-filter-chip:hover { color: var(--eng-ink); border-color: var(--eng-line-strong); }
.eng-filter-chip[aria-pressed="true"] { color: var(--eng-ink); background: var(--eng-accent-soft); border-color: rgba(217, 119, 6, .4); }
.eng-filter-chip[aria-pressed="true"] span { color: var(--eng-accent); }
.eng-entry[hidden] { display: none; }
.eng-entry mark { background: rgba(217, 119, 6, .22); color: inherit; padding: 0 .1em; border-radius: 3px; }
.eng-entry.is-match { animation: eng-match .35s var(--eng-ease); }
@keyframes eng-match { from { opacity: .3; transform: translateY(4px); } }

.eng-noresult, .eng-empty { text-align: center; padding: 3rem 1rem; color: var(--eng-muted); }
.eng-noresult[hidden] { display: none; }
.eng-noresult > :is(i, svg) { width: 26px; height: 26px; margin-bottom: .6rem; color: var(--eng-faint); }
.eng-noresult p { font-size: .92rem; margin: 0 0 .9rem; }
.eng-noresult strong { color: var(--eng-ink); }
.eng-empty { border-bottom: 1px solid var(--eng-line); }
.eng-empty-icon {
    width: 48px; height: 48px; margin: 0 auto 1rem; display: grid; place-items: center;
    border-radius: 14px; border: 1px solid rgba(217, 119, 6, .3); background: var(--eng-accent-soft); color: var(--eng-accent);
}
.eng-empty-icon :is(i, svg) { width: 22px; height: 22px; }
.eng-empty h3 { font-size: 1.05rem; font-weight: 600; color: var(--eng-ink); margin: 0 0 .35rem; }
.eng-empty p { font-size: .9rem; margin: 0 auto; max-width: 46ch; }

/* ─── Index: living hero + card illustrations (mlab-engineering-index.js) ─── */
.eng-life {
    position: absolute; inset: 0; width: 100%; height: 100%;
    mask-image: radial-gradient(ellipse 70% 90% at 100% 0%, #000 0%, transparent 70%);
    -webkit-mask-image: radial-gradient(ellipse 70% 90% at 100% 0%, #000 0%, transparent 70%);
    cursor: crosshair;
}
.eng-index-hero-inner { pointer-events: none; }
.eng-index-hero-inner :is(a, p, h1, .mlab-kv) { pointer-events: auto; }
.eng-eyebrow-dot { animation: eng-rec 2.4s ease-in-out infinite; }
@keyframes eng-rec {
    0%, 100% { box-shadow: 0 0 0 4px var(--eng-accent-soft); }
    50% { box-shadow: 0 0 0 7px rgba(217, 119, 6, 0); }
}
.eng-caret {
    display: inline-block; width: .09em; height: .82em; margin-left: .12em;
    background: var(--eng-accent); vertical-align: -.04em; border-radius: 1px;
    animation: eng-blink 1.1s steps(1) infinite;
}

.eng-art {
    position: relative; height: 84px; margin-bottom: 1.1rem;
    border: 1px solid var(--eng-line); border-radius: 12px; background: var(--eng-sunken);
    overflow: hidden;
}

/* 01: terminal */
.eng-art--term { padding: .7rem .85rem; font-family: var(--eng-mono); font-size: .7rem; line-height: 1.75; color: var(--eng-ink); }
.eng-art-line { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.eng-art-prompt { color: var(--eng-accent); font-weight: 600; }
.eng-art-line--dim { color: var(--eng-muted); }
.eng-art-line--ok { color: #15803d; }
html[data-bs-theme=dark] .eng-art-line--ok { color: #86efac; }
.eng-art-caret { display: inline-block; width: .5em; height: 1em; background: var(--eng-ink); vertical-align: -2px; margin-left: 1px; animation: eng-blink 1s steps(1) infinite; }
.eng-art-out { opacity: 0; transform: translateY(3px); }
.eng-art--term.is-done .eng-art-out { opacity: 1; transform: none; transition: opacity .35s ease calc(var(--d) * 280ms), transform .35s ease calc(var(--d) * 280ms); }
.eng-art--term.is-done .eng-art-caret { display: none; }

/* 02: the bar that loses */
.eng-art--bars { display: flex; align-items: flex-end; justify-content: center; gap: 14px; padding: 12px 0 20px; }
.eng-art-bar { position: relative; width: 26px; height: 100%; display: flex; align-items: flex-end; }
.eng-art-bar span {
    display: block; width: 100%; height: calc(var(--h) * 100%); border-radius: 4px 4px 0 0;
    background: var(--eng-neutral); transform-origin: 50% 100%; transform: scaleY(0);
}
.eng-art-bar--us span { background: var(--eng-accent); }
.eng-art-bar em {
    position: absolute; left: 50%; bottom: -16px; transform: translateX(-50%);
    font-style: normal; font-family: var(--eng-mono); font-size: .6rem; color: var(--eng-muted); white-space: nowrap;
}
.eng-art-oops {
    position: absolute; left: 50%; bottom: calc(var(--h) * 100% + 6px);
    font-family: var(--eng-mono); font-size: .6rem; font-weight: 600; color: var(--eng-accent);
    padding: .05rem .35rem; border-radius: 6px; background: var(--eng-surface); border: 1px solid rgba(217, 119, 6, .35);
    transform: translateX(-50%) scale(0); transform-origin: 50% 100%;
}
.eng-art--bars.is-play span { transform: scaleY(1); transition: transform .8s cubic-bezier(.34, 1.4, .64, 1) calc(var(--i) * 140ms); }
.eng-art--bars.is-play .eng-art-oops { transform: translateX(-50%) scale(1) rotate(-6deg); transition: transform .45s cubic-bezier(.34, 1.8, .64, 1) 1.05s; }

/* 03: odometer */
.eng-art--odo { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: .15rem; }
.eng-odo { display: flex; font-family: var(--eng-mono); font-size: 2rem; font-weight: 600; line-height: 1; height: 1em; color: var(--eng-ink); font-variant-numeric: tabular-nums; }
.eng-odo-static { display: block; }
.eng-odo-col { display: block; height: 1em; overflow: hidden; }
.eng-odo-strip { display: flex; flex-direction: column; transform: translateY(0); }
.eng-odo-strip span { display: block; height: 1em; }
.eng-art--odo.is-play .eng-odo-strip { transform: translateY(calc(var(--to) * -1em)); transition: transform 1.6s cubic-bezier(.2, .8, .2, 1) calc(var(--i) * 180ms); }
.eng-odo-cap { font-family: var(--eng-mono); font-size: .62rem; color: var(--eng-muted); letter-spacing: .03em; }

@media (max-width: 767.98px) {
    .eng-index-hero { padding: 1.8rem 1.25rem 1.2rem; }
    .eng-rules { grid-template-columns: 1fr; }
    .eng-rule + .eng-rule { border-left: 0; border-top: 1px solid var(--eng-line); }
    .eng-entry { grid-template-columns: minmax(0, 1fr); gap: .6rem; padding: 1.3rem .2rem; }
    .eng-entry-meta { flex-direction: row; gap: .8rem; padding-left: 0; }
    .eng-entry-side { display: none; }
    .eng-entry::before { display: none; }
}

/* ═══ Article header ══════════════════════════════════ */
.eng-head { max-width: 880px; margin: 1.5rem 0 2.6rem; }
@media (min-width: 992px) { .eng-head { margin-left: calc(220px + 3rem); } }
.eng-title {
    font-family: var(--eng-serif);
    font-size: clamp(2rem, 4vw, 3rem); font-weight: 600; line-height: 1.08; letter-spacing: -.03em;
    color: var(--eng-ink); margin: .2rem 0 1rem;
}
.eng-lead { font-size: 1.1rem; line-height: 1.7; color: var(--eng-muted); max-width: 68ch; margin-bottom: 1.4rem; }
.eng-meta {
    display: flex; flex-wrap: wrap; align-items: center; gap: .5rem 1.4rem;
    padding: .9rem 0; border-top: 1px solid var(--eng-line); border-bottom: 1px solid var(--eng-line);
    font-size: .84rem; color: var(--eng-muted);
}
.eng-meta-item { display: inline-flex; align-items: center; gap: .4rem; }
.eng-meta-item :is(i, svg) { width: 15px; height: 15px; }
.eng-meta-tags { display: inline-flex; flex-wrap: wrap; gap: .35rem; margin-left: auto; }
@media (max-width: 767.98px) { .eng-meta-tags { margin-left: 0; } }

/* ═══ Article layout ══════════════════════════════════ */
.eng-layout { grid-template-columns: 220px minmax(0, 1fr); gap: 3rem; }
@media (max-width: 991.98px) { .eng-layout { grid-template-columns: minmax(0, 1fr); gap: 1.25rem; } }

.eng-rail .mlab-report-nav-item { align-items: flex-start; white-space: normal; line-height: 1.35; padding: .45rem .65rem; font-size: .82rem; }
.eng-rail .mlab-report-nav-item > span:first-child { margin-right: 0; }
.eng-rail-num { font-family: var(--eng-mono); font-size: .68rem; color: var(--eng-faint); padding-top: .12rem; min-width: 1.2rem; }
.eng-rail .mlab-report-nav-item.active .eng-rail-num { color: var(--eng-accent); }
/* Second level sits under the chapter title, past its number. */
.eng-rail .mlab-report-nav-subs { margin: .1rem 0 .4rem 1.5rem; }
.eng-rail .mlab-report-nav-sub { white-space: normal; }
.eng-rail-progress { height: 2px; margin: .9rem .65rem 0; background: var(--eng-line); border-radius: 2px; overflow: hidden; }
.eng-rail-progress span { display: block; height: 100%; background: var(--eng-accent); transform-origin: 0 50%; transform: scaleX(var(--p, 0)); }
@media (max-width: 991.98px) {
    .eng-rail .mlab-report-nav-item { white-space: nowrap; }
    .eng-rail-progress { display: none; }
}

.eng-article { min-width: 0; counter-reset: eng-h2; }

/* ═══ Sections & prose ════════════════════════════════ */
.eng-section { padding: 0 0 3rem; scroll-margin-top: 88px; }
.eng-section + .eng-section { padding-top: 3rem; border-top: 1px solid var(--eng-line); }
.eng-section > h2 {
    counter-increment: eng-h2;
    display: flex; align-items: baseline; gap: .8rem;
    font-family: var(--eng-serif); font-weight: 600; font-size: 1.7rem; letter-spacing: -.02em; line-height: 1.2;
    color: var(--eng-ink); margin: 0 0 1.3rem; scroll-margin-top: 96px;
}
.eng-section > h2::before {
    content: counter(eng-h2, decimal-leading-zero);
    font-family: var(--eng-mono); font-size: .78rem; color: var(--eng-accent); font-weight: 600;
    transform: translateY(-.35rem);
}
.eng-section h3 {
    font-size: 1.08rem; font-weight: 600; color: var(--eng-ink);
    margin: 2.4rem 0 .7rem; scroll-margin-top: 96px;
}
.eng-section p, .eng-keypoints li, .eng-steps li, .eng-compare li {
    font-size: 1rem; line-height: 1.78; color: var(--eng-ink);
}
.eng-section p { margin: 0 0 1.15rem; }
.eng-section a:not([class]) {
    color: inherit; text-decoration: underline;
    text-decoration-color: color-mix(in srgb, var(--eng-accent) 55%, transparent);
    text-underline-offset: 3px; text-decoration-thickness: 1.5px;
    transition: text-decoration-color .15s ease;
}
.eng-section a:not([class]):hover { text-decoration-color: var(--eng-accent); }
.eng-section :not(pre) > code {
    font-family: var(--eng-mono); font-size: .86em;
    padding: .1em .38em; border-radius: 6px;
    background: var(--eng-sunken); border: 1px solid var(--eng-line);
    color: var(--eng-ink);
}
.eng-dropcap::first-letter {
    float: left; font-family: var(--eng-serif); font-size: 3.5rem; font-weight: 600; line-height: .8;
    padding: .42rem .55rem 0 0; color: var(--eng-accent);
}

.eng-keypoints { list-style: none; padding: 0; margin: 1.6rem 0 0; }
.eng-keypoints li { position: relative; padding: .7rem 0 .7rem 1.6rem; border-top: 1px solid var(--eng-line); }
.eng-keypoints li:last-child { border-bottom: 1px solid var(--eng-line); }
.eng-keypoints li::before {
    content: ""; position: absolute; left: .2rem; top: 1.45rem;
    width: 7px; height: 7px; border-radius: 2px; background: var(--eng-accent); transform: rotate(45deg);
}

/* Pull quote */
.eng-quote { margin: 2.2rem 0; padding: .2rem 0 .2rem 1.6rem; border-left: 2px solid var(--eng-accent); }
.eng-quote p { font-family: var(--eng-serif); font-size: 1.45rem; font-weight: 500; letter-spacing: -.015em; line-height: 1.38; color: var(--eng-ink); margin: 0; }

/* Footnotes */
.eng-fn-ref a { font-family: var(--eng-mono); font-size: .7rem; font-weight: 600; color: var(--eng-accent); text-decoration: none; padding: 0 .15rem; }
.eng-footnotes {
    margin: 2.6rem 0 0; padding: 1.2rem 0 0 1.2rem; border-top: 1px solid var(--eng-line);
    font-size: .84rem; color: var(--eng-muted);
}
.eng-footnotes li { font-size: .84rem !important; line-height: 1.65 !important; color: var(--eng-muted) !important; scroll-margin-top: 96px; }
.eng-footnotes li:target { color: var(--eng-ink) !important; }
.eng-fn-back { text-decoration: none; color: var(--eng-accent); margin-left: .2rem; }

/* ═══ Stat tiles ══════════════════════════════════════ */
.eng-stats {
    display: grid; grid-template-columns: repeat(4, minmax(0, 1fr));
    border: 1px solid var(--eng-line); border-radius: 16px; background: var(--eng-surface);
    overflow: hidden;
}
.eng-stat { position: relative; padding: 1.2rem 1.25rem 1rem; display: flex; flex-direction: column; min-height: 168px; }
.eng-stat + .eng-stat { border-left: 1px solid var(--eng-line); }
.eng-stat-label { font-size: .78rem; color: var(--eng-muted); }
.eng-stat-value { font-size: 2.1rem; font-weight: 600; letter-spacing: -.02em; color: var(--eng-ink); margin: .35rem 0 .15rem; font-variant-numeric: tabular-nums; }
.eng-stat-delta { font-size: .76rem; color: var(--eng-muted); }
.eng-stat-delta.is-up { color: #15803d; }
html[data-bs-theme=dark] .eng-stat-delta.is-up { color: #86efac; }
.eng-stat-delta.is-up::before { content: "▲ "; font-size: .62rem; }
.eng-spark { display: block; width: 100%; height: 34px; margin-top: auto; overflow: visible; }
.eng-spark-line { fill: none; stroke: var(--eng-neutral); stroke-width: 1.5; stroke-linejoin: round; stroke-linecap: round; }
.eng-spark-area { fill: var(--eng-accent-soft); stroke: none; }
.eng-spark-dot { fill: var(--eng-accent); stroke: var(--eng-surface); stroke-width: 2; }
@media (max-width: 991.98px) {
    .eng-stats { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .eng-stat:nth-child(3) { border-left: 0; }
    .eng-stat:nth-child(n+3) { border-top: 1px solid var(--eng-line); }
}

/* ═══ Callouts ════════════════════════════════════════ */
.eng-callout {
    display: flex; gap: .85rem; align-items: flex-start;
    padding: 1rem 1.15rem; margin: 1.6rem 0;
    border: 1px solid var(--eng-line); border-radius: 12px;
    background: var(--eng-sunken);
    font-size: .92rem; line-height: 1.65; color: var(--eng-ink);
}
.eng-callout > :is(i, svg) { width: 18px; height: 18px; flex: 0 0 auto; margin-top: .18rem; color: var(--eng-muted); }
.eng-callout strong { font-weight: 600; }
.eng-callout--sample { border-color: rgba(217, 119, 6, .28); background: var(--eng-accent-soft); margin: 1.2rem 0 0; }
.eng-callout--sample > :is(i, svg) { color: var(--eng-accent); }
.eng-callout--loss { border-color: rgba(220, 38, 38, .26); background: rgba(220, 38, 38, .05); }
.eng-callout--verified { border-color: rgba(22, 163, 74, .28); background: rgba(22, 163, 74, .06); }
.eng-callout--verified > :is(i, svg) { color: var(--eng-good); }
html[data-bs-theme=dark] .eng-callout--verified { background: rgba(34, 197, 94, .08); border-color: rgba(34, 197, 94, .30); }
.eng-callout--loss > :is(i, svg) { color: var(--eng-bad); }
html[data-bs-theme=dark] .eng-callout--loss { background: rgba(239, 68, 68, .08); border-color: rgba(239, 68, 68, .30); }

/* ═══ Figures & charts ════════════════════════════════ */
.eng-figure {
    margin: 2rem 0;
    border: 1px solid var(--eng-line); border-radius: 16px;
    background: var(--eng-surface);
    padding: 1.2rem 1.3rem 1rem;
}
.eng-figure-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 1rem; margin-bottom: 1rem; }
.eng-figure-num { font-family: var(--eng-mono); font-size: .68rem; letter-spacing: .04em; text-transform: uppercase; color: var(--eng-accent); font-weight: 600; }
.eng-figure-title { font-size: .98rem; font-weight: 600; color: var(--eng-ink); margin-top: .2rem; }
.eng-figure figcaption { font-size: .8rem; line-height: 1.6; color: var(--eng-muted); padding-top: .85rem; margin-top: .6rem; border-top: 1px solid var(--eng-line); }
.eng-figure-badge {
    display: inline-flex; align-items: center; gap: .4rem; flex: 0 0 auto;
    font-family: var(--eng-mono); font-size: .68rem; color: var(--eng-muted);
    padding: .25rem .6rem; border-radius: 999px; border: 1px solid var(--eng-line);
}
.eng-figure-badge :is(i, svg) { width: 12px; height: 12px; }
.eng-live-dot { width: 6px; height: 6px; border-radius: 50%; background: var(--eng-good); animation: eng-pulse 1.8s ease-in-out infinite; }
@keyframes eng-pulse { 50% { opacity: .3; } }
.eng-view-tabs { flex: 0 0 auto; }
.eng-view-tabs .mlab-ui-tab { font-size: .76rem; padding: .3rem .7rem; }

/* Reveal on scroll */
.eng-js .eng-figure, .eng-js .eng-stats, .eng-js .eng-code, .eng-js .eng-term, .eng-js .eng-compare, .eng-js .eng-repro {
    opacity: 0; transform: translateY(14px);
    transition: opacity .7s var(--eng-ease), transform .7s var(--eng-ease);
}
.eng-js .is-in { opacity: 1 !important; transform: none !important; }

.eng-legend { display: flex; flex-wrap: wrap; gap: .4rem 1.1rem; margin: 0 0 .8rem; font-size: .8rem; color: var(--eng-muted); }
.eng-legend-item { display: inline-flex; align-items: center; gap: .45rem; }
.eng-swatch { display: inline-block; width: 10px; height: 10px; border-radius: 3px; background: var(--eng-c, var(--eng-neutral)); flex: 0 0 auto; }
.eng-swatch--good { background: var(--eng-good); }
.eng-swatch--bad { background: var(--eng-bad); }
.eng-swatch--muted { background: var(--eng-neutral); }
.eng-swatch--warn { background: var(--eng-warn); }
.eng-swatch--faint { background: var(--eng-faint-fill); }
.eng-legend-item.is-off { opacity: .4; }
.eng-legend button.eng-legend-item { border: 0; background: none; padding: 0; color: inherit; font: inherit; cursor: pointer; }

.eng-chart { position: relative; }
.eng-chart svg { display: block; width: 100%; overflow: visible; }
.eng-chart [hidden] { display: none !important; }
.eng-chart-table { display: none; }
.eng-figure.is-table .eng-chart-svg, .eng-figure.is-table .eng-legend { display: none; }
.eng-figure.is-table .eng-chart-table { display: block; }

/* Axes, grid, labels */
.eng-ax-grid { stroke: var(--eng-grid); stroke-width: 1; shape-rendering: crispEdges; }
.eng-ax-base { stroke: var(--eng-line-strong); stroke-width: 1; shape-rendering: crispEdges; }
.eng-ax-text { fill: var(--eng-muted); font-size: 11px; font-family: var(--eng-mono); }
.eng-ax-title { fill: var(--eng-muted); font-size: 11px; }
.eng-cat-text { fill: var(--eng-ink); font-size: 12px; font-weight: 500; }
.eng-val-text { fill: var(--eng-ink); font-size: 11px; font-family: var(--eng-mono); font-weight: 600; }
.eng-val-text--in { fill: #fff; }

/* Marks */
.eng-mark-s1 { fill: var(--eng-s1); stroke: var(--eng-s1); }
.eng-mark-s2 { fill: var(--eng-s2); stroke: var(--eng-s2); }
.eng-mark-s3 { fill: var(--eng-s3); stroke: var(--eng-s3); }
.eng-mark-good { fill: var(--eng-good); }
.eng-mark-bad { fill: var(--eng-bad); }
.eng-mark-muted { fill: var(--eng-neutral); }
.eng-mark-warn { fill: var(--eng-warn); }
.eng-mark-faint { fill: var(--eng-faint-fill); }
.eng-ref-line { stroke: var(--eng-accent); stroke-width: 1.5; shape-rendering: crispEdges; }
rect.eng-bar, path.eng-bar { stroke: none; transition: opacity .2s ease; }
.eng-chart.has-focus .eng-bar:not(.is-focus) { opacity: .35; }

.eng-line { fill: none; stroke-width: 2; stroke-linejoin: round; stroke-linecap: round; }
.eng-area { stroke: none; opacity: .10; }
.eng-dot { stroke: var(--eng-surface); stroke-width: 2; }
.eng-cross { stroke: var(--eng-line-strong); stroke-width: 1; shape-rendering: crispEdges; }
.eng-hit { fill: transparent; cursor: crosshair; }
.eng-marker-line { stroke: var(--eng-ink); stroke-width: 1; stroke-dasharray: 0; opacity: .55; shape-rendering: crispEdges; }
.eng-marker-text { fill: var(--eng-ink); font-size: 11px; font-family: var(--eng-mono); font-weight: 600; }
.eng-annot-text { fill: var(--eng-muted); font-size: 11px; font-style: italic; }
.eng-heat-text { font-size: 11px; font-family: var(--eng-mono); font-weight: 600; fill: var(--eng-ink); pointer-events: none; }
.eng-heat-text.is-strong { fill: var(--eng-seq-on-hi); }
.eng-heat-scale { display: inline-block; width: 120px; height: 8px; border-radius: 4px; margin: 0 .5rem; background: linear-gradient(90deg in oklch, color-mix(in oklch, var(--eng-seq-hi) 8%, var(--eng-seq-lo)), var(--eng-seq-hi)); }
.eng-seg-text--good, .eng-seg-text--bad { fill: #fff; }
.eng-seg-text--muted, .eng-seg-text--faint { fill: var(--eng-ink); }
.eng-seg-text--warn { fill: #1f1400; }
html[data-bs-theme=dark] .eng-seg-text--good { fill: #052e16; }
.eng-heat-cell { stroke: var(--eng-surface); stroke-width: 2; transition: opacity .2s ease; }
.eng-chart.has-focus .eng-heat-cell:not(.is-focus) { opacity: .45; }

/* Entry animations (only once the figure scrolls in) */
.eng-anim .eng-bar-g { transform-box: fill-box; transform-origin: 50% 100%; transform: scaleY(0); }
.eng-anim .eng-bar-g--h { transform-origin: 0 50%; transform: scaleX(0); }
.eng-anim .eng-line { stroke-dasharray: 1; stroke-dashoffset: 1; }
.eng-anim .eng-area, .eng-anim .eng-dot, .eng-anim .eng-val-text, .eng-anim .eng-heat-cell, .eng-anim .eng-heat-text, .eng-anim .eng-marker { opacity: 0; }
.is-in .eng-anim .eng-bar-g { transform: none; transition: transform .9s var(--eng-ease) calc(var(--i, 0) * 70ms); }
.is-in .eng-anim .eng-line { stroke-dashoffset: 0; transition: stroke-dashoffset 1.6s cubic-bezier(.4, 0, .2, 1) calc(var(--i, 0) * 180ms); }
.is-in .eng-anim .eng-area { opacity: .10; transition: opacity .8s ease .9s; }
.is-in .eng-anim .eng-dot { opacity: 1; transition: opacity .3s ease calc(1.2s + var(--i, 0) * 180ms); }
.is-in .eng-anim .eng-val-text { opacity: 1; transition: opacity .4s ease calc(.6s + var(--i, 0) * 70ms); }
.is-in .eng-anim .eng-heat-cell, .is-in .eng-anim .eng-heat-text { opacity: 1; transition: opacity .5s ease calc(var(--i, 0) * 22ms); }
.is-in .eng-anim .eng-marker { opacity: 1; transition: opacity .5s ease calc(.9s + var(--i, 0) * 160ms); }

/* Table view generated from the chart spec */
.eng-chart-table .eng-table { margin: 0; }

/* Tooltip (one per page) */
.eng-tooltip {
    position: fixed; z-index: 1200; pointer-events: none;
    min-width: 140px; max-width: 280px;
    padding: .55rem .7rem; border-radius: 10px;
    background: var(--eng-surface); color: var(--eng-ink);
    border: 1px solid var(--eng-line-strong);
    box-shadow: 0 12px 32px -12px rgba(15, 23, 42, .28);
    font-size: .78rem; line-height: 1.45;
    opacity: 0; transform: translateY(4px); transition: opacity .12s ease, transform .12s ease;
}
.eng-tooltip.is-on { opacity: 1; transform: none; }
.eng-tooltip-title { font-weight: 600; margin-bottom: .3rem; }
.eng-tooltip-row { display: flex; align-items: center; gap: .45rem; }
.eng-tooltip-row .eng-swatch { width: 8px; height: 8px; }
.eng-tooltip-row b { margin-left: auto; padding-left: .8rem; font-family: var(--mlab-edit-mono); font-weight: 600; }
.eng-tooltip-sub { color: var(--mlab-text-secondary); font-size: .72rem; margin-top: .25rem; }

/* ═══ Diagram ═════════════════════════════════════════ */
.eng-diagram-scroll { overflow-x: auto; margin: 0 -.3rem; padding: 0 .3rem; }
.eng-diagram { min-width: 640px; height: auto; display: block; }
.eng-dg-node rect { fill: var(--eng-surface); stroke: var(--eng-line-strong); stroke-width: 1; }
.eng-dg-node--accent rect { fill: var(--eng-accent-soft); stroke: var(--eng-accent); }
.eng-dg-node--end rect { fill: var(--eng-sunken); }
.eng-dg-label { fill: var(--eng-ink); font-size: 14px; font-weight: 600; text-anchor: middle; }
.eng-dg-sub { fill: var(--eng-muted); font-size: 11px; font-family: var(--eng-mono); text-anchor: middle; }
.eng-dg-note { fill: var(--eng-muted); font-size: 11.5px; font-style: italic; text-anchor: middle; }
.eng-dg-tick { stroke: var(--eng-line-strong); stroke-width: 1; }
.eng-dg-flow { fill: none; stroke: var(--eng-faint); stroke-width: 1.5; stroke-dasharray: 4 5; animation: eng-flow 1.2s linear infinite; }
.eng-dg-flow--accent { stroke: var(--eng-accent); stroke-width: 2; animation-duration: .6s; }
.eng-dg-flow--loop { stroke-dasharray: 2 5; }
.eng-dg-arrowhead { fill: var(--eng-faint); }
.eng-dg-packet { fill: var(--eng-ink); }
.eng-dg-packet--accent { fill: var(--eng-accent); }
@keyframes eng-flow { to { stroke-dashoffset: -18; } }

/* ═══ Tables ══════════════════════════════════════════ */
.eng-table-wrap { overflow-x: auto; margin: 1.6rem 0; border: 1px solid var(--eng-line); border-radius: 14px; background: var(--eng-surface); }
.eng-table { width: 100%; border-collapse: collapse; font-size: .86rem; color: var(--eng-ink); }
.eng-table th {
    text-align: left; font-weight: 500; font-size: .7rem; letter-spacing: .04em; text-transform: uppercase;
    color: var(--eng-muted); padding: .75rem 1rem; border-bottom: 1px solid var(--eng-line-strong);
    background: var(--eng-sunken); vertical-align: bottom; line-height: 1.45;
}
.eng-table td { padding: .7rem 1rem; border-bottom: 1px solid var(--eng-line); vertical-align: top; line-height: 1.55; }
/* Text cells wrap so every column stays on screen; numbers keep one line. */
.eng-table td:is(.num, .nowrap) { white-space: nowrap; }
.eng-table td:first-child { min-width: 9rem; }
.eng-table tbody tr:last-child td { border-bottom: 0; }
.eng-table tbody tr { transition: background .15s ease; }
.eng-table tbody tr:hover { background: var(--eng-sunken); }
.eng-table .num { text-align: right; font-family: var(--eng-mono); font-variant-numeric: tabular-nums; }
.eng-table td.is-best { font-weight: 700; }
.eng-table td.is-best::after { content: ""; display: inline-block; width: 5px; height: 5px; border-radius: 50%; background: var(--eng-accent); margin-left: .4rem; vertical-align: middle; }
.eng-table tr.is-ours td:first-child { font-weight: 600; }
.eng-table td .eng-swatch { margin-right: .55rem; vertical-align: -1px; }

/* ═══ Code ════════════════════════════════════════════ */
.eng-code {
    margin: 1.6rem 0; border: 1px solid var(--eng-line); border-radius: 14px;
    background: var(--eng-code-bg); overflow: hidden;
}
.eng-code-head {
    display: flex; align-items: center; gap: .6rem;
    padding: .55rem .6rem .55rem 1rem; border-bottom: 1px solid var(--eng-line);
    background: var(--eng-surface);
    font-family: var(--eng-mono); font-size: .74rem; color: var(--eng-muted);
}
.eng-code-dots { display: inline-flex; gap: 5px; margin-right: .3rem; }
.eng-code-dots span { width: 9px; height: 9px; border-radius: 50%; background: var(--eng-line-strong); }
.eng-code-file { color: var(--eng-ink); }
.eng-code-lang { margin-left: auto; text-transform: uppercase; font-size: .64rem; letter-spacing: .06em; padding: .12rem .45rem; border-radius: 6px; border: 1px solid var(--eng-line); }
.eng-code-copy {
    display: inline-flex; align-items: center; gap: .35rem;
    border: 1px solid var(--eng-line); background: var(--eng-surface); color: var(--eng-muted);
    border-radius: 7px; padding: .22rem .5rem; font-family: var(--eng-mono); font-size: .68rem; cursor: pointer;
    transition: color .15s ease, border-color .15s ease;
}
.eng-code-copy:hover { color: var(--eng-ink); border-color: var(--eng-line-strong); }
.eng-code-copy :is(i, svg) { width: 13px; height: 13px; }
.eng-code-copy.is-done { color: var(--eng-good); }
.eng-code pre { margin: 0; padding: .85rem 0; overflow-x: auto; background: transparent; font-size: .82rem; line-height: 1.7; }
.eng-code code { font-family: var(--eng-mono); color: var(--eng-ink); background: none; padding: 0; border: 0; display: block; min-width: max-content; }
.eng-ln { display: block; padding: 0 1.1rem 0 0; position: relative; }
.eng-ln::before {
    content: attr(data-n); display: inline-block; width: 3.2rem; padding-right: 1rem;
    text-align: right; color: var(--eng-faint); user-select: none; font-size: .74rem;
}
.eng-ln.is-hl { background: var(--eng-code-hl); box-shadow: inset 2px 0 0 var(--eng-accent); }
.eng-ln.is-add { background: rgba(22, 163, 74, .09); box-shadow: inset 2px 0 0 var(--eng-good); }
.eng-ln.is-del { background: rgba(220, 38, 38, .08); box-shadow: inset 2px 0 0 var(--eng-bad); }
.eng-ln.is-del .eng-ln-text { opacity: .75; }
.tk-kw { color: var(--eng-code-kw); }
.tk-str { color: var(--eng-code-str); }
.tk-num { color: var(--eng-code-num); }
.tk-com { color: var(--eng-code-com); font-style: italic; }
.tk-fn { color: var(--eng-code-fn); }
.tk-ty { color: var(--eng-code-ty); }
.tk-key { color: var(--eng-code-fn); }

/* Terminal replay */
.eng-term { margin: 1.6rem 0; border-radius: 14px; overflow: hidden; background: #0b0c0e; border: 1px solid rgba(255, 255, 255, .08); color: #e5e7eb; }
.eng-term-head { display: flex; align-items: center; gap: .6rem; padding: .55rem .6rem .55rem 1rem; border-bottom: 1px solid rgba(255, 255, 255, .08); font-family: var(--eng-mono); font-size: .74rem; color: #9ca3af; }
.eng-term-head .eng-code-dots span:nth-child(1) { background: #ef4444; }
.eng-term-head .eng-code-dots span:nth-child(2) { background: #f59e0b; }
.eng-term-head .eng-code-dots span:nth-child(3) { background: #22c55e; }
.eng-term-replay { margin-left: auto; display: inline-flex; align-items: center; gap: .35rem; border: 1px solid rgba(255, 255, 255, .14); background: transparent; color: #d1d5db; border-radius: 7px; padding: .22rem .55rem; font-family: var(--eng-mono); font-size: .68rem; cursor: pointer; }
.eng-term-replay:hover { color: #fff; border-color: rgba(255, 255, 255, .3); }
.eng-term-replay :is(i, svg) { width: 13px; height: 13px; }
.eng-term-body { padding: 1rem 1.1rem 1.1rem; font-family: var(--eng-mono); font-size: .8rem; line-height: 1.75; min-height: 21rem; white-space: pre-wrap; word-break: break-word; }
.eng-term-line { display: block; }
.eng-term-prompt { color: #d97706; user-select: none; }
.eng-term-line--dim { color: #6b7280; }
.eng-term-line--ok { color: #86efac; }
.eng-term-line--warn { color: #fcd34d; }
.eng-term-caret { display: inline-block; width: .55em; height: 1.05em; background: #e5e7eb; vertical-align: -2px; animation: eng-blink 1s steps(1) infinite; }
@keyframes eng-blink { 50% { opacity: 0; } }

/* ═══ Formula ═════════════════════════════════════════ */
.eng-formula {
    display: flex; flex-wrap: wrap; align-items: center; gap: .6rem 1rem;
    margin: 1.6rem 0; padding: 1.3rem 1.5rem;
    border: 1px solid var(--eng-line); border-radius: 14px; background: var(--eng-sunken);
}
.eng-formula-lhs, .eng-formula-eq, .eng-formula-frac { font-family: var(--eng-math); font-style: italic; font-size: 1.7rem; color: var(--eng-ink); }
.eng-formula-frac { display: inline-flex; flex-direction: column; align-items: center; line-height: 1.2; font-size: 1.35rem; }
.eng-formula-frac span:first-child { border-bottom: 1.5px solid var(--eng-ink); padding: 0 .4rem .15rem; }
.eng-formula-frac span:last-child { padding-top: .15rem; }
.eng-formula-where { font-family: var(--eng-mono); font-size: .76rem; color: var(--eng-muted); margin-left: auto; }

/* ═══ Threshold explorer ══════════════════════════════ */
.eng-threshold-readout { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 0; border: 1px solid var(--eng-line); border-radius: 12px; margin-bottom: 1rem; }
.eng-readout { padding: .7rem .9rem; display: flex; flex-direction: column; gap: .2rem; }
.eng-readout + .eng-readout { border-left: 1px solid var(--eng-line); }
.eng-readout--wide { grid-column: span 2; }
.eng-readout-k { display: inline-flex; align-items: center; gap: .4rem; font-size: .74rem; color: var(--eng-muted); }
.eng-readout-v { font-family: var(--eng-mono); font-size: 1.35rem; font-weight: 600; color: var(--eng-ink); font-variant-numeric: tabular-nums; }
.eng-readout-v--sm { font-size: .95rem; padding-top: .3rem; }
.eng-threshold-control { display: grid; grid-template-columns: auto minmax(0, 1fr) auto; align-items: center; gap: 1rem; margin-top: .6rem; }
.eng-threshold-label { font-size: .82rem; color: var(--eng-muted); margin: 0; white-space: nowrap; }
.eng-threshold-label .eng-mono { color: var(--eng-ink); font-weight: 600; display: inline-block; min-width: 2.6rem; }
.eng-threshold-presets { display: inline-flex; gap: .35rem; }
.eng-chip-btn {
    font-size: .74rem; padding: .28rem .65rem; border-radius: 999px;
    border: 1px solid var(--eng-line); background: var(--eng-surface); color: var(--eng-muted); cursor: pointer;
    transition: color .15s ease, border-color .15s ease, background .15s ease;
}
.eng-chip-btn:hover { color: var(--eng-ink); border-color: var(--eng-line-strong); }
.eng-chip-btn.is-on { color: var(--eng-ink); background: var(--eng-accent-soft); border-color: rgba(217, 119, 6, .35); }

.eng-range { -webkit-appearance: none; appearance: none; width: 100%; height: 22px; background: transparent; cursor: pointer; }
.eng-range:focus { outline: none; }
.eng-range::-webkit-slider-runnable-track {
    height: 4px; border-radius: 4px;
    background: linear-gradient(90deg, var(--eng-accent) var(--fill, 50%), var(--eng-line-strong) var(--fill, 50%));
}
.eng-range::-moz-range-track { height: 4px; border-radius: 4px; background: var(--eng-line-strong); }
.eng-range::-moz-range-progress { height: 4px; border-radius: 4px; background: var(--eng-accent); }
.eng-range::-webkit-slider-thumb {
    -webkit-appearance: none; width: 18px; height: 18px; border-radius: 50%; margin-top: -7px;
    background: var(--eng-surface); border: 2px solid var(--eng-accent);
    box-shadow: 0 2px 6px rgba(15, 23, 42, .18); transition: transform .15s ease;
}
.eng-range::-moz-range-thumb { width: 14px; height: 14px; border-radius: 50%; background: var(--eng-surface); border: 2px solid var(--eng-accent); }
.eng-range:active::-webkit-slider-thumb { transform: scale(1.15); }
.eng-range:focus-visible::-webkit-slider-thumb { box-shadow: 0 0 0 4px var(--eng-accent-soft); }

@media (max-width: 767.98px) {
    .eng-threshold-readout { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .eng-readout--wide { grid-column: 1 / -1; border-left: 0 !important; border-top: 1px solid var(--eng-line); }
    .eng-threshold-control { grid-template-columns: minmax(0, 1fr); gap: .5rem; }
}

/* ═══ Compare, steps, repro, end ══════════════════════ */
.eng-compare { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); margin: 1.8rem 0; border: 1px solid var(--eng-line); border-radius: 14px; background: var(--eng-surface); overflow: hidden; }
.eng-compare-col { padding: 1.1rem 1.25rem; }
.eng-compare-col + .eng-compare-col { border-left: 1px solid var(--eng-line); background: linear-gradient(180deg, var(--eng-accent-soft), transparent 70%); }
.eng-compare-head { display: inline-flex; align-items: center; gap: .45rem; font-size: .8rem; font-weight: 600; margin-bottom: .6rem; }
.eng-compare-head :is(i, svg) { width: 15px; height: 15px; }
.eng-compare-head--before { color: var(--eng-muted); }
.eng-compare-head--after { color: var(--eng-accent); }
.eng-compare ul { list-style: none; padding: 0; margin: 0; }
.eng-compare li { position: relative; padding: .3rem 0 .3rem 1.2rem; font-size: .9rem !important; line-height: 1.6 !important; }
.eng-compare li::before { content: ""; position: absolute; left: 0; top: .9rem; width: 8px; height: 1.5px; background: var(--eng-faint); }
.eng-compare-col + .eng-compare-col li::before { background: var(--eng-accent); }
/* Two peers side by side, neither "before" nor "after". */
.eng-compare--peers .eng-compare-col + .eng-compare-col { background: none; }
.eng-compare--peers .eng-compare-col + .eng-compare-col li::before { background: var(--eng-faint); }
@media (max-width: 767.98px) {
    .eng-compare { grid-template-columns: minmax(0, 1fr); }
    .eng-compare-col + .eng-compare-col { border-left: 0; border-top: 1px solid var(--eng-line); }
}

.eng-steps { list-style: none; padding: 0; margin: 0; counter-reset: eng-step; }
.eng-steps li { counter-increment: eng-step; position: relative; padding: 1rem 0 1rem 3.2rem; border-top: 1px solid var(--eng-line); }
.eng-steps li:last-child { border-bottom: 1px solid var(--eng-line); }
.eng-steps li::before {
    content: counter(eng-step, decimal-leading-zero);
    position: absolute; left: 0; top: 1.1rem;
    font-family: var(--eng-mono); font-size: .8rem; font-weight: 600; color: var(--eng-accent);
    width: 2.2rem; height: 2.2rem; display: grid; place-items: center;
    border: 1px solid rgba(217, 119, 6, .3); border-radius: 10px; background: var(--eng-accent-soft);
}
.eng-steps strong { display: block; font-weight: 600; margin-bottom: .15rem; }

.eng-repro {
    display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 1.5rem;
    margin: 2.2rem 0 0; padding: 1.5rem; border: 1px solid var(--eng-line); border-radius: 16px;
    background: radial-gradient(ellipse 60% 120% at 0% 0%, var(--eng-accent-soft), transparent 70%), var(--eng-surface);
}
.eng-repro-title { font-family: var(--eng-serif); font-size: 1.25rem; font-weight: 600; letter-spacing: -.01em; color: var(--eng-ink); margin: -.3rem 0 .4rem; }
.eng-repro-copy p { font-size: .88rem !important; color: var(--eng-muted) !important; margin: 0; }
.eng-repro-files { display: flex; flex-direction: column; gap: .45rem; justify-content: center; }
.eng-file { display: flex; align-items: center; gap: .6rem; padding: .55rem .75rem; border: 1px solid var(--eng-line); border-radius: 10px; background: var(--eng-surface); font-family: var(--eng-mono); font-size: .76rem; color: var(--eng-ink); }
.eng-file :is(i, svg) { width: 15px; height: 15px; color: var(--eng-muted); }
.eng-file-size { margin-left: auto; color: var(--eng-muted); }
@media (max-width: 767.98px) { .eng-repro { grid-template-columns: minmax(0, 1fr); } }

.eng-end { margin-top: 1rem; }
.eng-end-card { display: flex; align-items: flex-end; justify-content: space-between; gap: 1.5rem; padding: 1.5rem; border: 1px solid var(--eng-line); border-radius: 16px; background: var(--eng-surface); }
.eng-end-author { font-size: 1.25rem; font-weight: 600; letter-spacing: -.01em; color: var(--eng-ink); margin-top: -.4rem; }
.eng-end-copy { color: var(--eng-muted); font-size: .88rem; margin: .3rem 0 0; max-width: 52ch; }
.eng-end-actions { display: flex; gap: .5rem; flex: 0 0 auto; }
.eng-end-actions :is(i, svg) { width: 15px; height: 15px; }
@media (max-width: 767.98px) { .eng-end-card { flex-direction: column; align-items: flex-start; } }

.eng-kv { margin: 1.4rem 0 1.6rem; }

/* ═══ Motion & print ══════════════════════════════════ */
@media (prefers-reduced-motion: reduce) {
    .eng-root *, .eng-root *::before { animation: none !important; transition: none !important; }
    .eng-art-bar span, .eng-art-out { transform: none !important; opacity: 1 !important; }
    .eng-art-oops { transform: translateX(-50%) scale(1) !important; }
    .eng-art-caret { display: none; }
    .eng-js .eng-figure, .eng-js .eng-stats, .eng-js .eng-code, .eng-js .eng-term, .eng-js .eng-compare, .eng-js .eng-repro { opacity: 1; transform: none; }
    .eng-anim .eng-bar-g { transform: none !important; }
    .eng-anim .eng-line { stroke-dashoffset: 0 !important; }
    .eng-anim .eng-area { opacity: .10 !important; }
    .eng-anim .eng-dot, .eng-anim .eng-val-text, .eng-anim .eng-heat-cell, .eng-anim .eng-heat-text, .eng-anim .eng-marker { opacity: 1 !important; }
}
@media print {
    .eng-progress, .mlab-report-rail, .eng-view-tabs, .eng-code-copy, .eng-term-replay, .eng-end-actions { display: none !important; }
    .eng-layout { grid-template-columns: 1fr !important; }
    .eng-js .eng-figure, .eng-js .eng-stats, .eng-js .eng-code, .eng-js .eng-term, .eng-js .eng-compare, .eng-js .eng-repro { opacity: 1 !important; transform: none !important; }
    .eng-figure, .eng-code, .eng-table-wrap { break-inside: avoid; }
}