/* ═══════════════════════════════════════════════════════════════════════
   Copper & Black design system
   Dark-only, flat "IDE / terminal" language (specs/007-ide-theme): solid
   panels, hairline borders, one flat copper accent, monospace labels.

   1 Tokens · 2 Base · 3 Layout · 4 Typography · 5 Components ·
   6 Site chrome · 7 Shared page pieces · 8 Command palette · 9 Blazor
   ═══════════════════════════════════════════════════════════════════════ */

/* ── 1. Tokens ─────────────────────────────────────────────────────────── */
:root {
    color-scheme: dark;
    interpolate-size: allow-keywords;

    /* Surfaces */
    --bc-bg-deep:     #0e0c0a;
    --bc-bg-primary:  #131110;
    --bc-bg-surface:  #1c1916;
    --bc-bg-elevated: #231f1b;
    --bc-bg-inset:    #0b0908;

    /* Lines */
    --bc-border:        #302a23;
    --bc-border-strong: #463c31;

    /* Text: every readable tier meets WCAG AA (4.5:1) on --bc-bg-surface */
    --bc-text-primary:   #f5ede0;   /* headings, emphasis   17:1  */
    --bc-text-body:      #cdbfac;   /* running text         9.7:1 */
    --bc-text-secondary: #a89070;   /* labels, tags         6.4:1 */
    --bc-text-muted:     #9a866e;   /* captions, hints      5.0:1 */
    --bc-text-faint:     #6e5a48;   /* decoration only, never text that must be read */

    /* Copper accent: flat fills and hairlines, never gradients or glow */
    --bc-accent:        #f97316;
    --bc-accent-light:  #fb923c;
    --bc-accent-deep:   #ea580c;
    --bc-on-accent:     #0e0c0a;    /* text on copper fills  7:1 */
    --bc-accent-dim:    rgba(249, 115, 22, 0.10);
    --bc-accent-border: rgba(249, 115, 22, 0.28);

    /* Type */
    --font-sans:    'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
    --font-display: 'Space Grotesk', 'Inter', system-ui, sans-serif;
    --font-mono:    'JetBrains Mono', ui-monospace, 'Cascadia Mono', Consolas, monospace;

    --text-2xs:     0.75rem;
    --text-xs:      0.8125rem;
    --text-sm:      0.875rem;
    --text-base:    clamp(1rem, 0.96rem + 0.18vw, 1.0625rem);
    --text-lg:      clamp(1.125rem, 1.05rem + 0.3vw, 1.25rem);
    --text-xl:      clamp(1.25rem, 1.12rem + 0.55vw, 1.5rem);
    --text-2xl:     clamp(1.6rem, 1.3rem + 1.4vw, 2.25rem);
    --text-3xl:     clamp(2.1rem, 1.6rem + 2.2vw, 3.25rem);
    --text-display: clamp(2.75rem, 1.8rem + 3.6vw, 4.5rem);

    --tracking-tight:   -0.025em;
    --tracking-display: -0.035em;
    --tracking-label:    0.08em;

    /* Space: 4px base */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.5rem;
    --space-6: 2rem;
    --space-7: 3rem;
    --space-8: 4rem;
    --space-9: 6rem;
    --section-y: clamp(3.5rem, 2rem + 5vw, 6.5rem);

    /* Layout */
    --container:        72rem;
    --container-wide:   86rem;
    --container-narrow: 46rem;
    --gutter:           clamp(1rem, 0.5rem + 2.5vw, 2rem);
    --header-h:         64px;   /* keep in sync with SiteTheme.LayoutProperties.AppbarHeight */

    /* Shape & motion */
    --bc-radius-sm: 4px;
    --bc-radius:    6px;
    --bc-radius-lg: 8px;
    --bc-radius-xl: 10px;
    --ease-out:     cubic-bezier(0.2, 0.8, 0.2, 1);
    --dur:          180ms;
    --shadow-overlay: 0 24px 70px rgba(0, 0, 0, 0.55);   /* floating layers only */
}

/* ── 2. Base ───────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }

html {
    -webkit-text-size-adjust: 100%;
    text-size-adjust: 100%;
    scroll-padding-top: calc(var(--header-h) + var(--space-4));
    scrollbar-color: var(--bc-border-strong) var(--bc-bg-deep);
    background: var(--bc-bg-deep);
}

body {
    margin: 0;
    min-height: 100dvh;
    overflow-x: clip;
    background: var(--bc-bg-deep);
    color: var(--bc-text-body);
    font-family: var(--font-sans);
    font-size: var(--text-base);
    font-weight: 400;
    line-height: 1.65;
    font-feature-settings: 'cv02', 'cv03', 'cv04', 'cv11';
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
    margin: 0;
    color: var(--bc-text-primary);
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: var(--tracking-tight);
    text-wrap: balance;
}

p, figure, blockquote, dl, dd { margin: 0; }
p { text-wrap: pretty; }
ul[class], ol[class] { margin: 0; padding: 0; list-style: none; }

:where(a) {
    color: var(--bc-accent-light);
    text-decoration-thickness: 1px;
    text-underline-offset: 0.2em;
}
:where(a:hover) { color: var(--bc-text-primary); }

img, picture, video, canvas { display: block; max-width: 100%; }
button, input, select, textarea { font: inherit; color: inherit; }
code, kbd, pre, samp { font-family: var(--font-mono); }
table { border-collapse: collapse; }

::selection { background: rgba(249, 115, 22, 0.35); color: var(--bc-text-primary); }

:where(a, button, summary, [tabindex], input[type="range"]):focus-visible {
    outline: 2px solid var(--bc-accent-light);
    outline-offset: 3px;
}

/* Programmatic focus targets (FocusOnNavigate, skip link) don't need a ring. */
h1:focus, main:focus { outline: none; }

.visually-hidden {
    position: absolute !important;
    width: 1px !important;
    height: 1px !important;
    padding: 0 !important;
    margin: -1px !important;
    overflow: hidden !important;
    clip: rect(0, 0, 0, 0) !important;
    white-space: nowrap !important;
    border: 0 !important;
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* ── 3. Layout ─────────────────────────────────────────────────────────── */
.container {
    width: 100%;
    max-width: calc(var(--container) + 2 * var(--gutter));
    margin-inline: auto;
    padding-inline: var(--gutter);
}
.container--wide   { max-width: calc(var(--container-wide) + 2 * var(--gutter)); }
.container--narrow { max-width: calc(var(--container-narrow) + 2 * var(--gutter)); }

.section { padding-block: var(--section-y); }
.section--flush-top { padding-top: 0; }

.stack   { display: flex; flex-direction: column; gap: var(--stack-gap, var(--space-4)); }
.cluster { display: flex; flex-wrap: wrap; align-items: center; gap: var(--cluster-gap, var(--space-3)); }

.grid-auto {
    display: grid;
    gap: var(--grid-gap, var(--space-5));
    grid-template-columns: repeat(auto-fill, minmax(min(100%, var(--grid-min, 18rem)), 1fr));
}

/* ── 4. Typography ─────────────────────────────────────────────────────── */
.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    margin: 0;
    color: var(--bc-accent-light);
    font-family: var(--font-mono);
    font-size: var(--text-2xs);
    font-weight: 500;
    letter-spacing: var(--tracking-label);
    line-height: 1.4;
    text-transform: uppercase;
}

/* Terminal-path eyebrow, e.g. "~/projects" */
.eyebrow--path { letter-spacing: 0.02em; text-transform: none; }

.display       { font-size: var(--text-display); line-height: 1.02; letter-spacing: var(--tracking-display); }
.page-title    { font-size: var(--text-3xl); line-height: 1.08; letter-spacing: -0.03em; }
.section-title { font-size: var(--text-2xl); }

.lead {
    max-width: 62ch;
    color: var(--bc-text-body);
    font-size: var(--text-lg);
    line-height: 1.6;
}

.prose { max-width: 68ch; }
.prose > * + * { margin-top: 1em; }

.muted       { color: var(--bc-text-muted); }
.mono        { font-family: var(--font-mono); }
.text-accent { color: var(--bc-accent-light); }

/* ── 5. Components ─────────────────────────────────────────────────────── */
.icon {
    display: inline-block;
    flex-shrink: 0;
    width: 1em;
    height: 1em;
    vertical-align: -0.125em;
}

/* Buttons: anchors and <button>s share one look */
.btn {
    --btn-bg: transparent;
    --btn-fg: var(--bc-text-primary);
    --btn-border: var(--bc-border-strong);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5em;
    min-height: 2.75rem;
    padding: 0.625rem 1.25rem;
    border: 1px solid var(--btn-border);
    border-radius: var(--bc-radius);
    background: var(--btn-bg);
    color: var(--btn-fg);
    font-family: var(--font-sans);
    font-size: 0.9375rem;
    font-weight: 600;
    line-height: 1.2;
    text-decoration: none;
    white-space: nowrap;
    cursor: pointer;
    transition: background-color var(--dur) var(--ease-out),
                border-color var(--dur) var(--ease-out),
                color var(--dur) var(--ease-out);
}
.btn:hover { --btn-bg: var(--bc-accent-dim); --btn-border: var(--bc-accent); }

.btn--primary       { --btn-bg: var(--bc-accent); --btn-fg: var(--bc-on-accent); --btn-border: var(--bc-accent); }
.btn--primary:hover { --btn-bg: var(--bc-accent-light); --btn-border: var(--bc-accent-light); }

.btn--lg    { min-height: 3rem; padding: 0.75rem 1.5rem; font-size: 1rem; }
.btn--sm    { min-height: 2.25rem; padding: 0.4rem 0.85rem; font-size: var(--text-sm); }
.btn--block { width: 100%; }

.btn.is-active,
.btn[aria-pressed="true"] { --btn-bg: var(--bc-accent-dim); --btn-border: var(--bc-accent); --btn-fg: var(--bc-accent-light); }

.btn:disabled,
.btn[aria-disabled="true"] { opacity: 0.55; cursor: not-allowed; pointer-events: none; }

.btn .icon { font-size: 1.15em; }
.btn .icon--trailing { transition: transform var(--dur) var(--ease-out); }
.btn:hover .icon--trailing { transform: translateX(2px); }

/* Square icon-only button: menu, close, social links */
.icon-btn {
    display: inline-grid;
    place-items: center;
    width: 2.5rem;
    height: 2.5rem;
    padding: 0;
    border: 1px solid var(--bc-border);
    border-radius: var(--bc-radius);
    background: transparent;
    color: var(--bc-text-body);
    font-size: 1.25rem;
    text-decoration: none;
    cursor: pointer;
    transition: background-color var(--dur) var(--ease-out),
                border-color var(--dur) var(--ease-out),
                color var(--dur) var(--ease-out);
}
.icon-btn:hover { border-color: var(--bc-accent-border); background: var(--bc-accent-dim); color: var(--bc-accent-light); }

/* Cards */
.card {
    position: relative;
    padding: var(--card-pad, clamp(1.25rem, 0.9rem + 1.2vw, 2rem));
    border: 1px solid var(--bc-border);
    border-radius: var(--bc-radius-lg);
    background: var(--bc-bg-surface);
}
.card--featured { border-color: var(--bc-accent-border); }

/* Flat copper top edge, like an active editor tab */
.card--featured::before {
    content: "";
    position: absolute;
    inset: -1px -1px auto;
    height: 2px;
    border-radius: var(--bc-radius-lg) var(--bc-radius-lg) 0 0;
    background: var(--bc-accent);
}

.card--interactive { transition: border-color var(--dur) var(--ease-out), background-color var(--dur) var(--ease-out); }
.card--interactive:hover,
.card--interactive:focus-within { border-color: var(--bc-accent-border); background: var(--bc-bg-elevated); }

.card--dashed { border-style: dashed; border-color: var(--bc-border-strong); background: transparent; }

.card__head  { display: flex; align-items: center; gap: var(--space-3); margin-bottom: var(--space-4); }
.card__title { font-size: var(--text-xl); }

.icon-tile {
    --tile: 2.75rem;
    display: inline-grid;
    place-items: center;
    flex-shrink: 0;
    width: var(--tile);
    height: var(--tile);
    border: 1px solid var(--bc-accent-border);
    border-radius: var(--bc-radius-lg);
    background: var(--bc-accent-dim);
    color: var(--bc-accent-light);
    font-size: calc(var(--tile) * 0.5);
}
.icon-tile--sm { --tile: 2.25rem; }
.icon-tile--lg { --tile: 3.5rem; }

/* Tags */
.tag-list { display: flex; flex-wrap: wrap; gap: var(--space-2); }

.tag {
    display: inline-flex;
    align-items: center;
    padding: 0.2rem 0.6rem;
    border: 1px solid var(--bc-border);
    border-radius: var(--bc-radius-sm);
    background: var(--bc-bg-elevated);
    color: var(--bc-text-secondary);
    font-family: var(--font-mono);
    font-size: var(--text-xs);
    line-height: 1.5;
    white-space: nowrap;
}
.tag--accent { border-color: var(--bc-accent-border); color: var(--bc-accent-light); }
.tag--strong { color: var(--bc-text-primary); }

/* Inline metrics, e.g. "134,400 nodes · Mach 0.3" */
.metric-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-1) var(--space-4);
    color: var(--bc-accent-light);
    font-family: var(--font-mono);
    font-size: var(--text-xs);
}
.metric-list > li { display: inline-flex; align-items: center; gap: var(--space-2); }
.metric-list > li::before {
    content: "";
    width: 5px;
    height: 5px;
    border-radius: 1px;
    background: currentColor;
    opacity: 0.7;
}

/* Stats */
.stat { display: flex; flex-direction: column; gap: var(--space-1); }
.stat__value {
    color: var(--bc-accent-light);
    font-family: var(--font-mono);
    font-size: var(--text-2xl);
    font-weight: 700;
    line-height: 1.15;
    letter-spacing: -0.02em;
}
.stat__label { color: var(--bc-text-primary); font-weight: 600; }
.stat__hint  { color: var(--bc-text-muted); font-size: var(--text-sm); }

/* Segmented control (two-state view switch) */
.segmented {
    display: inline-flex;
    gap: 2px;
    padding: 3px;
    border: 1px solid var(--bc-border);
    border-radius: var(--bc-radius);
    background: var(--bc-bg-primary);
}
.segmented__btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.4rem 0.9rem;
    border: 0;
    border-radius: calc(var(--bc-radius) - 2px);
    background: transparent;
    color: var(--bc-text-secondary);
    font-family: var(--font-mono);
    font-size: var(--text-xs);
    cursor: pointer;
    transition: background-color var(--dur) var(--ease-out), color var(--dur) var(--ease-out);
}
.segmented__btn:hover { color: var(--bc-text-primary); }
.segmented__btn[aria-pressed="true"] {
    background: var(--bc-bg-elevated);
    box-shadow: inset 0 0 0 1px var(--bc-accent-border);
    color: var(--bc-accent-light);
}

/* Native <details> accordion */
.disclosure {
    border: 1px solid var(--bc-border);
    border-radius: var(--bc-radius-lg);
    background: var(--bc-bg-surface);
    transition: border-color var(--dur) var(--ease-out);
}
.disclosure + .disclosure { margin-top: var(--space-2); }
.disclosure:hover,
.disclosure[open] { border-color: var(--bc-border-strong); }

.disclosure > summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-4);
    padding: 1rem 1.25rem;
    color: var(--bc-text-primary);
    font-weight: 600;
    list-style: none;
    cursor: pointer;
}
.disclosure > summary::-webkit-details-marker { display: none; }
.disclosure > summary::after {
    content: "+";
    color: var(--bc-accent-light);
    font-family: var(--font-mono);
    font-size: 1.25rem;
    line-height: 1;
    transition: transform var(--dur) var(--ease-out);
}
.disclosure[open] > summary::after { transform: rotate(45deg); }
.disclosure__body { padding: 0 1.25rem 1.25rem; color: var(--bc-text-body); }

/* Animated open/close where ::details-content and interpolate-size are supported */
.disclosure::details-content {
    block-size: 0;
    overflow: hidden;
    transition: block-size 250ms var(--ease-out), content-visibility 250ms allow-discrete;
}
.disclosure[open]::details-content { block-size: auto; }

/* ── 6. Site chrome ────────────────────────────────────────────────────── */

/* Animated maze behind every page (maze-background.js sizes it to the viewport) */
.maze-bg {
    position: fixed;
    inset: 0;
    z-index: 0;
    display: block;
    width: 100vw;
    height: 100vh;
    background: var(--bc-bg-deep);
    pointer-events: none;
}

.skip-link {
    position: fixed;
    top: var(--space-2);
    left: var(--space-2);
    z-index: 2100;
    padding: 0.6rem 1rem;
    border-radius: var(--bc-radius);
    background: var(--bc-accent);
    color: var(--bc-on-accent);
    font-weight: 600;
    text-decoration: none;
    transform: translateY(-200%);
    transition: transform var(--dur) var(--ease-out);
}
.skip-link:focus { transform: none; }

/* Header (MudAppBar). An inset shadow draws the hairline without adding to the 64px height. */
.site-header { box-shadow: inset 0 -1px 0 var(--bc-border); }

.site-header__inner {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    gap: var(--space-4);
    flex: 1 1 auto;
    min-width: 0;
    height: 100%;
}
.site-header .brand       { grid-column: 1; justify-self: start; }
.site-header .site-nav    { grid-column: 2; }
.site-header__actions {
    display: flex;
    grid-column: 3;
    justify-self: end;
    align-items: center;
    gap: var(--space-2);
}

.brand {
    color: var(--bc-accent-light);
    font-family: var(--font-display);
    font-size: 1.2rem;
    font-weight: 700;
    line-height: 1;
    letter-spacing: -0.03em;
    text-decoration: none;
    white-space: nowrap;
}
.brand__bracket { color: var(--bc-text-faint); }
.brand--lg { font-size: 1.6rem; }

.site-nav { display: none; }
.site-nav__list { display: flex; gap: var(--space-1); }
.site-nav__link {
    display: inline-flex;
    align-items: center;
    height: 2.25rem;
    padding: 0 0.85rem;
    border-radius: var(--bc-radius);
    color: var(--bc-text-body);
    font-size: var(--text-sm);
    font-weight: 500;
    text-decoration: none;
    transition: background-color var(--dur) var(--ease-out), color var(--dur) var(--ease-out);
}
.site-nav__link:hover { background: var(--bc-accent-dim); color: var(--bc-text-primary); }
.site-nav__link.active {
    background: var(--bc-accent-dim);
    box-shadow: inset 0 -2px 0 var(--bc-accent);
    color: var(--bc-accent-light);
}

.menu-toggle { display: inline-grid; }

.cmdk-trigger {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    height: 2.5rem;
    padding: 0 0.75rem;
    border: 1px solid var(--bc-border);
    border-radius: var(--bc-radius);
    background: transparent;
    color: var(--bc-text-secondary);
    font-size: var(--text-sm);
    cursor: pointer;
    transition: border-color var(--dur) var(--ease-out), color var(--dur) var(--ease-out);
}
.cmdk-trigger:hover { border-color: var(--bc-accent-border); color: var(--bc-text-primary); }
.cmdk-trigger .icon { font-size: 1.15rem; }
.cmdk-trigger-label,
.cmdk-trigger-keys { display: none; }
.cmdk-trigger-keys {
    padding: 0.05rem 0.4rem;
    border: 1px solid var(--bc-border);
    border-radius: var(--bc-radius-sm);
    background: var(--bc-bg-deep);
    color: var(--bc-text-muted);
    font-family: var(--font-mono);
    font-size: var(--text-2xs);
}

/* command-palette.js adds .is-mac to <html>, which Blazor never re-renders. */
.kbd-mac { display: none; }
.is-mac .kbd-mac { display: inline; }
.is-mac .kbd-other { display: none; }

@media (min-width: 600px) {
    .cmdk-trigger-label,
    .cmdk-trigger-keys { display: inline; }
}

@media (min-width: 900px) {
    .site-nav { display: block; }
    .menu-toggle { display: none; }
}

/* Mobile drawer (MudDrawer) */
.site-drawer.mud-drawer { border-left: 1px solid var(--bc-border); }

.drawer-panel {
    display: flex;
    flex-direction: column;
    gap: var(--space-5);
    height: 100%;
    padding: var(--space-4);
}
.drawer-panel__head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: calc(var(--header-h) - 2 * var(--space-4));
}
.drawer-nav__list { display: grid; gap: var(--space-1); }
.drawer-nav__link {
    display: flex;
    align-items: center;
    min-height: 3rem;
    padding: 0 var(--space-4);
    border-radius: var(--bc-radius);
    color: var(--bc-text-body);
    font-size: 1.0625rem;
    font-weight: 500;
    text-decoration: none;
}
.drawer-nav__link:hover { background: var(--bc-accent-dim); color: var(--bc-text-primary); }
.drawer-nav__link.active {
    background: var(--bc-accent-dim);
    box-shadow: inset 2px 0 0 var(--bc-accent);
    color: var(--bc-accent-light);
}
.drawer-panel__social {
    margin-top: auto;
    padding-top: var(--space-4);
    border-top: 1px solid var(--bc-border);
}

/* Page shell: sits above the maze canvas, footer pinned to the bottom */
.site-shell {
    position: relative;
    z-index: 1;
    display: flex;
    flex-direction: column;
    min-height: 100dvh;
}
.site-main { flex: 1 0 auto; }

/* Footer */
.site-footer {
    margin-top: var(--space-8);
    border-top: 1px solid var(--bc-border);
    background: var(--bc-bg-primary);
}
.site-footer__grid {
    display: grid;
    gap: var(--space-7);
    padding-block: var(--space-8) var(--space-7);
}
.site-footer__tagline { margin-top: var(--space-3); color: var(--bc-text-body); }
.site-footer__brand .social-links { margin-top: var(--space-5); }

.social-links { display: flex; gap: var(--space-2); }

.footer-heading {
    margin-bottom: var(--space-4);
    color: var(--bc-text-muted);
    font-family: var(--font-mono);
    font-size: var(--text-2xs);
    font-weight: 500;
    letter-spacing: var(--tracking-label);
    text-transform: uppercase;
}
.footer-links   { display: grid; gap: var(--space-2); }
.footer-contact { display: grid; gap: var(--space-3); }
.footer-contact li { display: flex; align-items: center; gap: var(--space-3); overflow-wrap: anywhere; }
.footer-contact .icon { color: var(--bc-text-secondary); font-size: 1.15rem; }
.footer-links a,
.footer-contact a { color: var(--bc-text-body); text-decoration: none; }
.footer-links a:hover,
.footer-contact a:hover { color: var(--bc-accent-light); }

.site-footer__bottom {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: var(--space-2) var(--space-5);
    padding-block: var(--space-5);
    border-top: 1px solid var(--bc-border);
    color: var(--bc-text-muted);
    font-size: var(--text-sm);
}

@media (min-width: 760px) {
    .site-footer__grid { grid-template-columns: 1.4fr 1fr 1fr; }
}

/* ── 7. Shared page pieces ─────────────────────────────────────────────── */
.page-header {
    padding-block: clamp(2.5rem, 1.5rem + 4vw, 4.5rem) clamp(1.5rem, 1rem + 2vw, 2.5rem);
}
.page-header .page-title { margin-top: var(--space-3); }
.page-header .lead { margin-top: var(--space-4); }

.section-head {
    display: flex;
    flex-wrap: wrap;
    align-items: end;
    justify-content: space-between;
    gap: var(--space-4);
    margin-bottom: var(--space-6);
}
.section-head .section-title { margin-top: var(--space-2); }
.section-head .lead { margin-top: var(--space-3); }

/* Math (KaTeX is inserted by JS, so these can't live in scoped CSS) */
.math-block {
    overflow-x: auto;
    padding: clamp(1rem, 0.75rem + 1vw, 1.5rem);
    border: 1px solid var(--bc-border);
    border-left: 3px solid var(--bc-accent);
    border-radius: var(--bc-radius);
    background: var(--bc-bg-inset);
}
.math-formula {
    color: var(--bc-text-primary);
    font-size: clamp(1rem, 0.9rem + 0.5vw, 1.25rem);
    text-align: center;
}

/* Hide raw LaTeX until KaTeX has typeset it; reveal it anyway if KaTeX never loads. */
.math-formula:not([data-rendered]) {
    visibility: hidden;
    animation: math-reveal 0s linear 5s forwards;
}
@keyframes math-reveal { to { visibility: visible; } }

.math-block .katex { font-size: 1.1em; }
.math-block .katex-display { margin: 0; }

.eq-legend-wrap { overflow-x: auto; }
.eq-legend { width: 100%; margin-top: var(--space-3); font-size: var(--text-sm); }
.eq-legend th,
.eq-legend td { padding: 0.45rem 0.75rem; text-align: left; vertical-align: top; }
.eq-legend tr + tr > * { border-top: 1px solid var(--bc-border); }
.eq-legend th {
    width: 11rem;
    color: var(--bc-accent-light);
    font-family: var(--font-mono);
    font-weight: 600;
    white-space: nowrap;
}
.eq-legend td { color: var(--bc-text-body); }

/* ── 8. Command palette (⌘K) ───────────────────────────────────────────── */
.cmdk-overlay {
    position: fixed;
    inset: 0;
    z-index: 2000;
    display: flex;
    align-items: flex-start;
    justify-content: center;
    padding-top: 14vh;
    background: rgba(8, 7, 6, 0.55);
    backdrop-filter: blur(4px);
    opacity: 0;
    transition: opacity 0.18s ease;
}
/* The rule above would otherwise override [hidden] and leave an invisible overlay eating clicks. */
.cmdk-overlay[hidden] { display: none; }
.cmdk-overlay--open { opacity: 1; }

.cmdk-panel {
    display: flex;
    flex-direction: column;
    width: min(92vw, 560px);
    max-height: 60vh;
    overflow: hidden;
    border: 1px solid var(--bc-accent-border);
    border-radius: var(--bc-radius-lg);
    background: var(--bc-bg-elevated);
    box-shadow: var(--shadow-overlay);
    transform: translateY(-8px);
    transition: transform 0.18s ease;
}
.cmdk-overlay--open .cmdk-panel { transform: translateY(0); }

.cmdk-input-wrap {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 18px;
    border-bottom: 1px solid var(--bc-border);
}
.cmdk-search-icon { width: 1.1rem; height: 1.1rem; flex-shrink: 0; color: var(--bc-accent-light); }
.cmdk-input {
    flex: 1;
    border: none;
    outline: none;
    background: transparent;
    color: var(--bc-text-primary);
    font-family: var(--font-display);
    font-size: 1.05rem;
}
.cmdk-input::placeholder { color: var(--bc-text-muted); }

.cmdk-list { margin: 0; padding: 8px; overflow-y: auto; list-style: none; }
.cmdk-row {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 11px 14px;
    border-radius: var(--bc-radius);
    color: var(--bc-text-secondary);
    cursor: pointer;
}
.cmdk-row--active {
    background: var(--bc-accent-dim);
    box-shadow: inset 0 0 0 1px var(--bc-accent-border);
    color: var(--bc-text-primary);
}
.cmdk-row-icon { width: 1.15rem; height: 1.15rem; flex-shrink: 0; color: var(--bc-accent-light); }
.cmdk-row-label { flex: 1; font-family: var(--font-display); font-weight: 500; }
.cmdk-row-hint {
    color: var(--bc-text-muted);
    font-family: var(--font-mono);
    font-size: 0.72rem;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}
.cmdk-row--copied .cmdk-row-hint { color: var(--bc-accent-light); }
.cmdk-empty { padding: 20px; color: var(--bc-text-muted); font-size: 0.9rem; text-align: center; }

.cmdk-footer {
    display: flex;
    gap: 18px;
    padding: 10px 18px;
    border-top: 1px solid var(--bc-border);
    color: var(--bc-text-muted);
    font-size: 0.72rem;
}
.cmdk-footer kbd {
    margin-right: 3px;
    padding: 1px 5px;
    border: 1px solid var(--bc-border);
    border-radius: var(--bc-radius-sm);
    background: var(--bc-bg-deep);
    color: var(--bc-text-secondary);
    font-family: var(--font-mono);
}

@media (prefers-reduced-motion: reduce) {
    .cmdk-overlay, .cmdk-panel { transition: none; }
}

/* ── 9. Blazor ─────────────────────────────────────────────────────────── */
.blazor-error-boundary {
    padding: 1rem 1.25rem;
    border: 1px solid var(--bc-border);
    border-left: 3px solid #f87171;
    border-radius: var(--bc-radius);
    background: var(--bc-bg-elevated);
    color: var(--bc-text-primary);
}
.blazor-error-boundary::after { content: "An error has occurred."; }