/* Page immersive du système — son cadre (en-tête, trame, pied), ses chapitres, les principes et les
   strates du contexte, la lumière des mesures et la médiation épistémique. Le thème bascule à seuil :
   les jetons --immersion-* passent des rôles canoniques de luxis aux couleurs de nuit de System selon
   --immersion-mix (0 à l'arrivée, 100 % après un défilement court), que sgbl_immersion.js écrit sur le
   corps de la page ; sans script, la page reste claire. --immersion-grid révèle la trame au milieu du
   troisième chapitre. */

@layer page {
    @property --immersion-night {
        syntax: "<number>";
        inherits: true;
        initial-value: 0;
    }
    @property --immersion-grid {
        syntax: "<number>";
        inherits: true;
        initial-value: 0;
    }
    .immersion {
        --immersion-mix: 0%;
        --immersion-ink-mix: 0%;
        --immersion-contrast-boost: 0%;
        --immersion-canvas: color-mix(in srgb, var(--local-color-identity-night-canvas) var(--immersion-mix), var(--canon-theme-canvas));
        --immersion-surface-base: color-mix(in srgb, var(--local-color-identity-night-surface) var(--immersion-mix), var(--canon-theme-surface));
        --immersion-surface: color-mix(in srgb, var(--immersion-canvas) var(--immersion-contrast-boost), var(--immersion-surface-base));
        --immersion-raised: color-mix(in srgb, var(--local-color-identity-night-raised) var(--immersion-mix), var(--canon-theme-raised));
        --immersion-ink: color-mix(in srgb, var(--local-color-identity-night-ink) var(--immersion-ink-mix), var(--canon-theme-ink));
        --immersion-muted-base: color-mix(in srgb, var(--local-color-identity-night-muted) var(--immersion-ink-mix), var(--canon-theme-faint));
        --immersion-muted: color-mix(in srgb, var(--immersion-ink) var(--immersion-contrast-boost), var(--immersion-muted-base));
        --immersion-line: color-mix(in srgb, var(--local-color-identity-night-line) var(--immersion-mix), var(--canon-theme-line));
        --immersion-action-base: color-mix(in srgb, var(--local-color-identity-night-action) var(--immersion-mix), var(--canon-theme-action));
        --immersion-action: color-mix(in srgb, var(--immersion-ink) var(--immersion-contrast-boost), var(--immersion-action-base));
        --immersion-action-soft: color-mix(in srgb, var(--immersion-action) 16%, transparent);
        --immersion-glass-edge: color-mix(in srgb, var(--immersion-ink) 16%, transparent);
        --immersion-glass-shine: color-mix(in srgb, var(--immersion-ink) 30%, transparent);
        --immersion-glass-tint: color-mix(in srgb, var(--immersion-ink) 6%, transparent);
        --immersion-signal: color-mix(in srgb, var(--local-color-identity-night-signal) var(--immersion-mix), var(--local-color-identity-signal));
        --immersion-signal-tint: color-mix(in srgb, var(--immersion-signal) 10%, transparent);
        --immersion-perimeter: color-mix(in srgb, var(--local-color-identity-night-perimeter) var(--immersion-mix), var(--canon-theme-action));
        --immersion-perimeter-tint: color-mix(in srgb, var(--immersion-perimeter) 5%, transparent);
        --immersion-perimeter-line: color-mix(in srgb, var(--immersion-perimeter) 42%, var(--immersion-line));
        --immersion-envelope-line: color-mix(in srgb, var(--immersion-ink) 37%, var(--immersion-line));
        --immersion-envelope-glow: color-mix(in srgb, var(--immersion-action) 6%, transparent);
        --immersion-server-line: color-mix(in srgb, var(--immersion-action) 37%, var(--immersion-line));
        --immersion-node-line: color-mix(in srgb, var(--immersion-ink) 34%, var(--immersion-line));
        --immersion-node-tint: color-mix(in srgb, var(--immersion-action) 6%, var(--immersion-canvas));
    }
    .chapters {
        --chapters-pointer-strength: 0;
        --chapters-pointer-top: 100%;
        --chapters-pointer-left: 50%;
    }

    .immersion {
        overflow-x: clip;
    }
    .immersion-lattice {
        position: fixed;
        inset: 0;
        z-index: 0;
    }
    .immersion-header {
        position: fixed;
        inset: 0 0 auto;
        z-index: 20;
        min-height: 60px;
        padding: 0 clamp(20px, 4vw, 56px);
        display: grid;
        grid-template-columns: auto 1fr auto;
        align-items: center;
        gap: 24px;
    }
    .immersion-brand {
        display: inline-flex;
        align-items: center;
        gap: 10px;
    }
    .immersion-brand img {
        width: 26px;
        height: 26px;
    }
    .immersion-menu {
        justify-self: center;
        display: flex;
        gap: 26px;
    }
    .immersion-menu a {
        padding: 6px 0;
    }
    .immersion-index {
        justify-self: end;
    }
    .immersion-main {
        position: relative;
        z-index: 1;
        width: 100%;
    }
    .chapter {
        position: relative;
        min-height: 0;
        padding: clamp(112px, 15vh, 176px) clamp(20px, 7vw, 112px) clamp(80px, 11vh, 136px);
        display: flex;
        align-items: center;
        overflow: clip;
    }
    .chapter::before {
        position: absolute;
        inset: -20%;
        z-index: 0;
    }
    .chapter--intro {
        padding-top: clamp(140px, 22vh, 220px);
    }
    .chapter-content {
        position: relative;
        z-index: 2;
        width: min(100%, 1180px);
        margin: 0 auto;
    }
    .chapter--diagram .chapter-content {
        width: min(100%, 1420px);
        display: grid;
        grid-template-columns: minmax(260px, 0.8fr) minmax(0, 1.4fr);
        align-items: center;
        gap: clamp(32px, 4vw, 64px);
    }
    .kicker {
        margin: 0 0 24px;
        display: flex;
        align-items: center;
        gap: 12px;
    }
    .kicker::before {
        width: 24px;
        height: 1px;
    }
    .chapter h1 {
        max-width: 16ch;
        margin: 0 0 32px;
    }
    .chapter h2 {
        max-width: 20ch;
        margin: 0 0 28px;
    }
    .chapter h3 {
        margin: 0 0 12px;
    }
    .principle h2 {
        max-width: none;
        margin-bottom: 18px;
    }
    .lead,
    .chapter-text,
    .principle p,
    .mediation p,
    .strata-message,
    .mediation-message {
        max-width: var(--canon-width-reading);
    }
    .lead {
        margin: 0;
    }
    .chapters {
        margin-top: 44px;
        display: grid;
        grid-template-columns: repeat(4, minmax(0, 1fr));
    }
    .chapters a {
        position: relative;
        overflow: hidden;
        padding: 18px 16px;
        display: flex;
        flex-direction: column;
        gap: 14px;
    }
    .chapters a:first-child {
        padding-left: 0;
    }
    .chapters a::before {
        position: absolute;
        inset: 0;
    }
    .chapters a::after {
        position: absolute;
        height: 3px;
        width: 100%;
        left: 0;
        bottom: 0;
    }
    .chapters a > span {
        display: flex;
        justify-content: space-between;
    }
    .chapters a:hover > span::after {
        transform: translateX(4px);
    }
    .principle {
        padding: 28px;
    }
    .chapter--intro .principle {
        width: min(100%, 72ch);
        margin-top: 40px;
    }
    .principle p {
        margin: 0;
    }
    .principle p + p {
        margin-top: 14px;
    }
    .cue {
        margin: 64px 0 0;
        display: flex;
        align-items: center;
        gap: 14px;
    }
    .cue span {
        position: relative;
        width: 56px;
        height: 1px;
        overflow: hidden;
    }
    .cue span::after {
        position: absolute;
        inset: 0 auto 0 0;
        width: 40%;
    }
    .chapter-text {
        margin: 0;
        max-width: 60ch;
    }
    .principles {
        margin-top: 56px;
        display: grid;
        grid-template-columns: repeat(3, minmax(0, 1fr));
        gap: 1px;
    }
    .principles .principle {
        position: relative;
        padding: 56px 28px 30px;
    }
    .principles .index {
        position: absolute;
        top: 24px;
        left: 28px;
    }
    .strata {
        position: relative;
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        gap: 48px;
        margin-top: 28px;
        padding: 30px 0;
        overflow: hidden;
    }
    .strata-item {
        min-width: 0;
        position: relative;
        display: flex;
        align-items: center;
        justify-content: space-around;
        gap: 12px;
        padding: 20px 8px;
    }
    .strata-item > span {
        position: absolute;
        top: -12px;
        left: 8px;
    }
    .strata-item i {
        height: 7px;
        width: 7px;
        transform: rotate(45deg);
    }
    .strata-beam {
        position: absolute;
        top: 50%;
        width: 60%;
        height: 1px;
        transform: translateX(-120%);
    }
    .strata-message,
    .mediation-message {
        min-height: 2.8em;
        margin: 1em 0 0;
    }
    .glow {
        position: relative;
    }
    .glow > canvas {
        position: absolute;
        top: -240px;
        left: 0;
        width: 100%;
        height: calc(100% + 520px);
        z-index: 1;
    }
    .measures {
        position: relative;
        padding: clamp(80px, 10vw, 128px) clamp(20px, 7vw, 112px);
    }
    .measures-head {
        margin-bottom: clamp(36px, 5vw, 60px);
        display: flex;
        align-items: center;
        justify-content: space-between;
        gap: 24px;
    }
    .measures-head .kicker {
        margin: 0;
    }
    .measures-stamp {
        margin: 0;
        display: flex;
        align-items: center;
        gap: 10px;
    }
    .measures-stamp::before {
        width: 6px;
        height: 6px;
    }
    .measures-grid {
        margin: 0;
        display: grid;
        grid-template-columns: repeat(3, minmax(0, 1fr));
        gap: 16px;
    }
    .measures-grid > div {
        position: relative;
        min-width: 0;
        padding: 40px 28px 30px;
        display: flex;
        flex-direction: column;
    }
    .measures-grid dt {
        order: 2;
        margin-top: 22px;
    }
    .measures-grid dt > span {
        display: block;
        margin-top: 6px;
    }
    .measures-grid dd {
        order: 1;
        min-height: 1em;
        margin: 0;
    }
    .measures-note {
        max-width: 78ch;
        margin: 20px 0 0;
    }
    .mediation-action {
        margin-top: 24px;
        width: auto;
        gap: 24px;
    }
    .mediation {
        margin-top: 24px;
        display: grid;
        grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr);
        align-items: stretch;
        gap: 14px;
    }
    .mediation article {
        padding: 26px;
    }
    .mediation article > span {
        display: block;
        margin-bottom: 20px;
    }
    .mediation p {
        margin: 0;
    }
    .mediation-arrow {
        align-self: center;
    }
    .immersion-footer {
        position: relative;
        z-index: 1;
        min-height: 80px;
        padding: 24px clamp(20px, 7vw, 112px);
        display: flex;
        align-items: center;
        justify-content: space-between;
        gap: 24px;
    }
    .immersion-defs {
        position: absolute;
        width: 0;
        height: 0;
        overflow: hidden;
    }
    @media (width > 800px) {
        .chapter--intro .chapter-content {
            display: grid;
            grid-template-columns: minmax(0, 6fr) minmax(22rem, 4fr);
            grid-template-areas:
                "kicker principle"
                "title principle"
                "lead principle"
                "nav nav"
                "cue cue";
            align-items: start;
            column-gap: clamp(48px, 7vw, 112px);
        }
        .chapter--intro .kicker {
            grid-area: kicker;
        }
        .chapter--intro h1 {
            grid-area: title;
        }
        .chapter--intro .lead {
            grid-area: lead;
        }
        .chapter--intro .principle {
            grid-area: principle;
            width: 100%;
            margin-top: 0;
            align-self: center;
        }
        .chapter--intro .chapters {
            grid-area: nav;
            margin-top: 56px;
        }
        .chapter--intro .cue {
            grid-area: cue;
        }
    }
    @media (max-width: 800px) {
        .immersion-header {
            grid-template-columns: auto 1fr;
        }
        .immersion-menu {
            display: none;
        }
        .chapter--diagram .chapter-content {
            grid-template-columns: 1fr;
            gap: 40px;
        }
        .chapters {
            grid-template-columns: repeat(2, minmax(0, 1fr));
        }
        .chapters a:nth-child(odd) {
            padding-left: 0;
        }
        .principles,
        .measures-grid,
        .mediation {
            grid-template-columns: 1fr;
        }
        .mediation-arrow {
            justify-self: start;
            transform: rotate(90deg);
        }
    }
    @media (max-width: 600px) {
        .immersion-index {
            display: none;
        }
        .chapter {
            padding: 120px 20px 72px;
        }
        .chapters a {
            padding: 14px 12px;
        }
        .principle,
        .mediation article {
            padding: 22px;
        }
        .principles .principle {
            padding: 52px 22px 26px;
        }
        .principles .index {
            left: 22px;
        }
        .strata {
            grid-template-columns: 1fr;
            gap: 24px;
            padding: 28px 0;
        }
        .measures {
            padding: 64px 20px 72px;
        }
        .measures-head {
            align-items: flex-start;
            flex-direction: column;
            gap: 12px;
        }
        .measures-grid > div {
            padding: 32px 22px 26px;
        }
        .immersion-footer {
            align-items: flex-start;
            flex-direction: column;
        }
    }
    @media (prefers-reduced-motion: reduce) {
        .chapters a:hover > span::after {
            transform: none;
        }
        .glow > canvas {
            visibility: hidden;
        }
    }

    .immersion {
        background: var(--immersion-canvas);
    }
    .immersion-lattice {
        opacity: calc(var(--immersion-grid) * 0.72);
        background-image:
            linear-gradient(var(--immersion-line) 1px, transparent 1px),
            linear-gradient(90deg, var(--immersion-line) 1px, transparent 1px);
        background-size: 96px 96px;
        -webkit-mask-image: radial-gradient(ellipse 90% 85% at 50% 40%, #000 30%, transparent 100%);
        mask-image: radial-gradient(ellipse 90% 85% at 50% 40%, #000 30%, transparent 100%);
    }
    .immersion-header {
        background: color-mix(in srgb, var(--immersion-canvas) 76%, transparent);
        border-bottom: 1px solid var(--immersion-line);
        backdrop-filter: blur(16px) saturate(1.1);
    }
    .immersion-brand img {
        filter: invert(var(--immersion-night));
    }
    .immersion-menu a {
        border-bottom: 1px solid transparent;
    }
    .immersion-menu a[aria-current="location"] {
        border-bottom-color: var(--immersion-action);
    }
    .immersion :is(button, summary):focus-visible {
        outline: 2px solid var(--immersion-signal);
        outline-offset: 4px;
    }
    .chapter {
        isolation: isolate;
    }
    .chapter--intro::before {
        background: radial-gradient(circle at 84% 12%, var(--immersion-action-soft), transparent 30rem);
    }
    .chapter--episteme {
        border-top: 1px solid var(--immersion-line);
    }
    .kicker::before {
        background: var(--immersion-action);
    }
    .chapters {
        border-block: 1px solid var(--immersion-line);
    }
    .chapters a {
        border-left: 1px solid var(--immersion-line);
    }
    .chapters a:first-child {
        border-left: 0;
    }
    .immersion-menu a:focus-visible,
    .chapters a:focus-visible {
        outline: 2px solid var(--immersion-action);
        outline-offset: 2px;
    }
    .chapters a::before {
        background: radial-gradient(ellipse 160px 90px at var(--chapters-pointer-left) var(--chapters-pointer-top), color-mix(in srgb, var(--immersion-action) 18%, transparent), transparent 100%);
        opacity: var(--chapters-pointer-strength);
    }
    .chapters a::after {
        background: radial-gradient(ellipse 115px 4px at var(--chapters-pointer-left) 100%, var(--immersion-ink) 0%, var(--immersion-action) 15%, transparent 100%);
        opacity: var(--chapters-pointer-strength);
    }
    .chapters a:focus-visible::after {
        opacity: 1;
    }
    .principle {
        background: color-mix(in srgb, var(--immersion-surface) 72%, transparent);
        border: 1px solid var(--immersion-line);
        border-radius: 4px;
        backdrop-filter: blur(12px);
    }
    .cue span {
        background: var(--immersion-line);
    }
    .cue span::after {
        background: var(--immersion-action);
    }
    .principles {
        background: var(--immersion-line);
        border: 1px solid var(--immersion-line);
    }
    .principles .principle {
        background: var(--immersion-canvas);
        border: 0;
        border-radius: 0;
        backdrop-filter: none;
    }
    .principles .principle:has([aria-pressed="true"]) {
        background: linear-gradient(150deg, var(--immersion-action-soft), var(--immersion-canvas) 70%);
    }
    .principles .principle:hover {
        background: var(--immersion-raised);
    }
    .strata {
        border-block: 1px solid var(--immersion-line);
    }
    .strata-item {
        background: linear-gradient(90deg, transparent, var(--immersion-line) 50%, transparent) center / 100% 1px no-repeat;
    }
    .strata-item i {
        border: 1px solid var(--immersion-muted);
    }
    .strata[data-strata-view="address"] i {
        background: var(--immersion-action);
        box-shadow: 0 0 12px var(--immersion-action-soft);
    }
    .strata[data-strata-view="preserve"] .strata-item {
        border-left: 1px solid var(--immersion-action);
        background-color: var(--immersion-action-soft);
    }
    .strata[data-strata-view="compose"] i {
        opacity: 0.24;
    }
    .strata[data-strata-view="compose"] i:nth-child(3),
    .strata[data-strata-view="compose"] i:nth-child(4) {
        background: var(--immersion-signal);
        border-color: var(--immersion-signal);
        box-shadow: 0 0 16px var(--immersion-signal);
        opacity: 1;
    }
    .strata-beam {
        background: linear-gradient(90deg, transparent, var(--immersion-signal), transparent);
    }
    .glow {
        isolation: isolate;
    }
    .measures {
        border-block: 1px solid var(--immersion-line);
        background: color-mix(in srgb, var(--immersion-surface) 55%, var(--immersion-canvas));
    }
    .measures-stamp::before {
        border-radius: 50%;
        background: var(--immersion-action);
        box-shadow: 0 0 0 0 var(--immersion-action-soft);
    }
    .measures-grid > div {
        isolation: isolate;
        background: linear-gradient(135deg, var(--immersion-glass-tint), transparent 58%);
        border: 1px solid var(--immersion-glass-tint);
        border-radius: 20px;
        box-shadow:
            inset 1px 1px 0 var(--immersion-glass-tint),
            inset -1px -1px 0 color-mix(in srgb, var(--immersion-glass-edge) 30%, transparent);
        backdrop-filter: saturate(1.4) brightness(1.08) blur(5px);
        backdrop-filter: url("#glass") saturate(1.4) brightness(1.08) blur(5px);
    }
    .measures-grid > div:hover {
        border-color: var(--immersion-glass-shine);
    }
    .mediation article {
        background: color-mix(in srgb, var(--immersion-surface) 72%, transparent);
        border: 1px solid var(--immersion-line);
        border-top: 2px solid var(--immersion-action);
        border-radius: 0 0 4px 4px;
    }
    .mediation article[data-reached] {
        border-top-color: var(--immersion-signal);
        background: linear-gradient(160deg, var(--immersion-signal-tint), transparent 75%);
    }
    .mediation article[aria-current="step"] {
        box-shadow: 0 -12px 35px -22px var(--immersion-signal);
    }
    .immersion-footer {
        background: var(--immersion-canvas);
        border-top: 1px solid var(--immersion-line);
    }
    @media (max-width: 800px) {
        .chapters a:nth-child(odd) {
            border-left: 0;
        }
        .chapters a:nth-child(n + 3) {
            border-top: 1px solid var(--immersion-line);
        }
    }

    .immersion {
        color: var(--immersion-ink);
        font-weight: var(--canon-weight-body);
        letter-spacing: var(--canon-tracking-body);
    }
    .immersion-header {
        color: var(--immersion-ink);
    }
    .immersion-brand {
        color: var(--immersion-ink);
        font-size: 0.9rem;
        font-weight: 700;
        letter-spacing: 0.14em;
        text-decoration: none;
    }
    .immersion-menu a,
    .chapters a {
        color: var(--immersion-ink);
        text-decoration: none;
    }
    .immersion-menu a {
        color: var(--immersion-muted);
        font-size: 0.7rem;
        font-weight: 500;
        letter-spacing: 0.14em;
        text-transform: uppercase;
    }
    .immersion-menu a:hover,
    .immersion-menu a[aria-current="location"] {
        color: var(--immersion-ink);
    }
    .immersion-index {
        color: var(--immersion-muted);
        font-size: 0.72rem;
        font-variant-numeric: tabular-nums;
        letter-spacing: 0.12em;
    }
    .chapter::before,
    .kicker::before,
    .chapters a::before,
    .chapters a::after,
    .cue span::after,
    .measures-stamp::before {
        content: "";
    }
    .kicker {
        color: var(--immersion-muted);
        font-size: 0.7rem;
        font-weight: 500;
        letter-spacing: 0.18em;
        text-transform: uppercase;
    }
    .index {
        color: var(--immersion-action);
    }
    .principles .index {
        font-size: 0.68rem;
        letter-spacing: 0.14em;
    }
    .chapter h1,
    .chapter h2,
    .chapter h3 {
        font-family: var(--canon-font-figura);
        color: var(--immersion-ink);
        text-wrap: balance;
    }
    .chapter h1 {
        font-size: clamp(2.9rem, 7.4vw, 7.2rem);
        line-height: 0.92;
        letter-spacing: -0.05em;
        font-weight: 600;
    }
    .chapter h2 {
        font-size: clamp(2.1rem, 4.6vw, 4.8rem);
        line-height: 0.98;
        letter-spacing: -0.04em;
        font-weight: 600;
    }
    .chapter h3 {
        font-size: clamp(1.15rem, 1.9vw, 1.55rem);
        line-height: 1.15;
        letter-spacing: -0.02em;
        font-weight: 600;
    }
    .principle h2 {
        font-size: clamp(1.25rem, 1.8vw, 1.6rem);
        line-height: 1.15;
        letter-spacing: -0.02em;
    }
    .lead,
    .chapter-text,
    .principle p,
    .mediation p {
        text-align: left;
        line-height: 1.6;
    }
    .lead {
        color: var(--immersion-muted);
        font-size: clamp(1.05rem, 1.45vw, 1.3rem);
    }
    .chapters a {
        font-size: 0.92rem;
        font-weight: 580;
        letter-spacing: -0.01em;
    }
    .chapters a > span {
        color: var(--immersion-muted);
        font-size: 0.68rem;
        letter-spacing: 0.14em;
    }
    .chapters a > span::after {
        content: "→";
        color: var(--immersion-action);
    }
    .principle p {
        color: var(--immersion-muted);
        font-size: 0.98rem;
    }
    .cue {
        color: var(--immersion-muted);
        font-size: 0.66rem;
        letter-spacing: 0.18em;
        text-transform: uppercase;
    }
    .chapter-text {
        color: var(--immersion-muted);
        font-size: 1.02rem;
    }
    .strata-item > span {
        font-size: 0.62rem;
        text-transform: uppercase;
        letter-spacing: 0.14em;
        color: var(--immersion-muted);
    }
    .strata-message,
    .mediation-message {
        color: var(--immersion-muted);
        font-size: 0.85rem;
        line-height: 1.65;
    }
    .measures-stamp {
        color: var(--immersion-muted);
        font-size: 0.7rem;
        letter-spacing: 0.12em;
        text-transform: uppercase;
    }
    .measures-grid > div {
        text-align: left;
    }
    .measures-grid dt {
        color: var(--immersion-ink);
        font-size: 0.9rem;
        font-weight: 560;
        line-height: 1.45;
        letter-spacing: -0.01em;
    }
    .measures-grid dt > span {
        color: var(--immersion-muted);
        font-size: 0.68rem;
        font-weight: 500;
        letter-spacing: 0.06em;
    }
    .measures-grid dd {
        color: var(--immersion-ink);
        font-size: clamp(3.6rem, 7.2vw, 7rem);
        font-variant-numeric: tabular-nums;
        font-weight: 560;
        line-height: 0.9;
        letter-spacing: -0.06em;
        text-align: left;
        white-space: nowrap;
    }
    .measures-note {
        color: var(--immersion-muted);
        font-size: 0.68rem;
        line-height: 1.6;
        letter-spacing: 0.04em;
    }
    .mediation-action {
        font-size: 0.85rem;
        color: var(--immersion-signal);
    }
    .mediation-action:hover {
        color: var(--immersion-action);
    }
    .mediation article > span {
        color: var(--immersion-action);
        font-size: 0.68rem;
        font-weight: 500;
        letter-spacing: 0.16em;
        text-transform: uppercase;
    }
    .mediation p {
        color: var(--immersion-muted);
        font-size: 0.95rem;
    }
    .mediation-arrow {
        color: var(--immersion-action);
        font-size: 1.3rem;
    }
    .mediation-arrow[data-reached] {
        color: var(--immersion-signal);
        text-shadow: 0 0 14px var(--immersion-signal);
    }
    .immersion-footer {
        color: var(--immersion-muted);
        font-size: 0.72rem;
        letter-spacing: 0.08em;
    }
    .immersion-footer a {
        color: var(--immersion-ink);
        text-decoration: underline;
        text-underline-offset: 0.2em;
    }
    @media (width > 800px) {
        .chapter--intro h1 {
            font-size: clamp(3.2rem, 5.6vw, 6.4rem);
        }
    }

    .immersion-menu,
    .chapters {
        user-select: none;
    }
    .immersion-lattice,
    .chapter::before,
    .chapters a::before,
    .chapters a::after,
    .glow > canvas {
        pointer-events: none;
    }
    .chapters a::before {
        transition: opacity 220ms ease;
    }
    .chapters a::after {
        transition: opacity 180ms ease;
    }
    .chapters a > span::after {
        transition: transform 140ms ease;
    }
    .cue span::after {
        animation: cue-sweep 1.8s ease-in-out infinite;
    }
    .strata-item i {
        transition: background 250ms ease, box-shadow 250ms ease, opacity 250ms ease;
    }
    .strata[data-running] .strata-beam {
        animation: strata-sweep 900ms ease-out;
    }
    .measures-stamp::before {
        animation: measures-pulse 2.4s ease-out infinite;
    }
    .measures-grid > div {
        transition: border-color 140ms ease;
    }
    .mediation article {
        transition: border-color 160ms ease, background 160ms ease;
    }
    @media (prefers-reduced-motion: reduce) {
        .chapters a::after,
        .chapters a > span::after,
        .strata-item i,
        .mediation article {
            transition: none;
        }
        .cue span::after,
        .measures-stamp::before,
        .strata[data-running] .strata-beam {
            animation: none;
        }
    }
    @keyframes cue-sweep {
        from {
            transform: translate3d(-100%, 0, 0);
        }
        to {
            transform: translate3d(260%, 0, 0);
        }
    }
    @keyframes strata-sweep {
        to {
            transform: translateX(120%);
        }
    }
    @keyframes measures-pulse {
        0% {
            box-shadow: 0 0 0 0 color-mix(in srgb, var(--immersion-action) 45%, transparent);
        }
        70% {
            box-shadow: 0 0 0 8px transparent;
        }
        100% {
            box-shadow: 0 0 0 0 transparent;
        }
    }
}