:root {
    --paper: #f6f8f8;
    --paper-strong: #ffffff;
    --ink: #263541;
    --ink-strong: #192631;
    --muted: #667680;
    --line: #cfd9dc;
    --line-strong: #aebdc2;
    --signal: #2f8394;
    --signal-strong: #246f7e;
    --signal-soft: #dcebed;
    --signal-wash: #edf5f6;
    --inverse: #16232c;
    --inverse-2: #1e303a;
    --inverse-text: #edf4f5;
    --inverse-muted: #a9bbc1;
    --shadow: 0 22px 60px rgba(22, 35, 44, 0.08);
    --rail-height: 68px;
}

:root[data-theme="dark"] {
    --paper: #0b1115;
    --paper-strong: #10181d;
    --ink: #e7eef0;
    --ink-strong: #ffffff;
    --muted: #94a5ab;
    --line: #28363c;
    --line-strong: #3b4c53;
    --signal: #3b95a6;
    --signal-strong: #55adba;
    --signal-soft: #17363e;
    --signal-wash: #10272d;
    --inverse: #e8eff1;
    --inverse-2: #d8e3e6;
    --inverse-text: #16232c;
    --inverse-muted: #52636a;
    --shadow: 0 22px 60px rgba(0, 0, 0, 0.22);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--rail-height) + 24px);
}

body {
    min-width: 320px;
    background: var(--paper);
    color: var(--ink);
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    line-height: 1.55;
    text-rendering: optimizeLegibility;
    transition: background-color 180ms ease, color 180ms ease;
}

a {
    color: inherit;
}

button,
a {
    -webkit-tap-highlight-color: transparent;
}

.site-rail {
    position: sticky;
    top: 0;
    z-index: 100;
    min-height: var(--rail-height);
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    gap: 2.25rem;
    padding: 0 2.2rem;
    border-bottom: 1px solid var(--line);
    background: color-mix(in srgb, var(--paper) 92%, transparent);
    backdrop-filter: blur(16px);
}

.rail-brand {
    display: inline-flex;
    align-items: center;
    text-decoration: none;
}

.logo-stack {
    display: grid;
    position: relative;
}

.logo-stack > img {
    grid-area: 1 / 1;
    width: 100%;
    height: auto;
    display: block;
    transition: opacity 140ms ease;
}

.logo-stack--rail {
    width: 176px;
}

.logo-stack--opening {
    width: min(520px, 100%);
    margin-bottom: 2.15rem;
}

.theme-logo--dark {
    opacity: 0;
    pointer-events: none;
}

:root[data-theme="dark"] .theme-logo--light {
    opacity: 0;
    pointer-events: none;
}

:root[data-theme="dark"] .theme-logo--dark {
    opacity: 1;
}

.rail-nav {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1.65rem;
    min-width: 0;
}

.rail-nav a,
.site-footer a {
    text-decoration: none;
    color: var(--muted);
    font-size: 0.79rem;
    font-weight: 680;
    letter-spacing: 0.02em;
    transition: color 140ms ease;
}

.rail-nav a:hover,
.site-footer a:hover {
    color: var(--ink-strong);
}

.rail-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.theme-switch {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    border: 0;
    background: transparent;
    color: var(--muted);
    font: inherit;
    font-size: 0.75rem;
    font-weight: 700;
    cursor: pointer;
}

.theme-switch__track {
    width: 34px;
    height: 18px;
    border: 1px solid var(--line-strong);
    border-radius: 999px;
    padding: 2px;
    display: inline-flex;
    align-items: center;
}

.theme-switch__thumb {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--ink);
    transition: transform 160ms ease, background 160ms ease;
}

:root[data-theme="dark"] .theme-switch__thumb {
    transform: translateX(14px);
    background: var(--signal-strong);
}

.rail-contact {
    text-decoration: none;
    border: 1px solid var(--line-strong);
    padding: 0.55rem 0.85rem;
    font-size: 0.76rem;
    font-weight: 760;
    letter-spacing: 0.03em;
    transition: border-color 140ms ease, background 140ms ease;
}

.rail-contact:hover {
    border-color: var(--signal);
    background: var(--signal-wash);
}

.opening-statement,
.platform-ledger,
.deployment-field,
.architecture-notes,
.closing-band,
.site-footer {
    width: min(1240px, calc(100% - 3rem));
    margin-inline: auto;
}

.opening-statement {
    padding: 5rem 0 5.4rem;
}

.opening-marker,
.section-index,
.profile-label,
.topology-label,
.context-type {
    font-size: 0.68rem;
    font-weight: 820;
    letter-spacing: 0.18em;
    text-transform: uppercase;
}

.opening-marker {
    display: flex;
    align-items: center;
    gap: 0.7rem;
    color: var(--signal-strong);
    margin-bottom: 2rem;
}

.opening-marker span {
    display: inline-block;
    width: 38px;
    height: 2px;
    background: var(--signal);
}

.opening-layout {
    display: grid;
    grid-template-columns: minmax(0, 1.7fr) minmax(290px, 0.7fr);
    gap: clamp(3rem, 7vw, 7rem);
    align-items: end;
}

.opening-title {
    max-width: 850px;
    font-size: clamp(2.5rem, 5vw, 5.35rem);
    line-height: 0.98;
    letter-spacing: -0.055em;
    font-weight: 760;
    color: var(--ink-strong);
}

.opening-title span {
    color: var(--signal-strong);
}

.opening-intro {
    max-width: 800px;
    margin-top: 1.85rem;
    font-size: clamp(1rem, 1.35vw, 1.18rem);
    color: var(--muted);
}

.opening-actions,
.closing-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
    margin-top: 2rem;
}

.action {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 44px;
    padding: 0.72rem 1rem;
    text-decoration: none;
    font-size: 0.8rem;
    font-weight: 790;
    letter-spacing: 0.02em;
    border: 1px solid transparent;
    transition: transform 140ms ease, border-color 140ms ease, background 140ms ease;
}

.action:hover {
    transform: translateY(-1px);
}

.action--solid {
    background: var(--signal-strong);
    color: #ffffff;
}

.action--solid:hover {
    background: var(--signal);
}

.action--line {
    border-color: var(--line-strong);
    color: var(--ink-strong);
    background: transparent;
}

.action--line:hover {
    border-color: var(--signal);
    background: var(--signal-wash);
}

.operating-profile {
    border-top: 2px solid var(--ink-strong);
    border-bottom: 1px solid var(--line);
    padding: 1rem 0 0;
}

.profile-label {
    color: var(--muted);
    margin-bottom: 0.6rem;
}

.operating-profile dl > div {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 1rem;
    padding: 0.78rem 0;
    border-top: 1px solid var(--line);
}

.operating-profile dt {
    color: var(--muted);
    font-size: 0.82rem;
}

.operating-profile dd {
    color: var(--ink-strong);
    font-size: 0.82rem;
    font-weight: 760;
    text-align: right;
}

.platform-ledger {
    padding: 1rem 0 6rem;
}

.section-intro {
    display: grid;
    grid-template-columns: 180px minmax(0, 1fr);
    gap: 1.5rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--line);
}

.section-index {
    color: var(--signal-strong);
    padding-top: 0.35rem;
}

.section-intro h2,
.identity-heading h2,
.architecture-copy h2,
.closing-band h2 {
    color: var(--ink-strong);
    font-size: clamp(1.85rem, 3vw, 3rem);
    line-height: 1.05;
    letter-spacing: -0.04em;
    font-weight: 760;
}

.section-intro p {
    max-width: 780px;
    margin-top: 0.9rem;
    color: var(--muted);
}

.ledger {
    border-bottom: 1px solid var(--line);
}

.ledger-row {
    display: grid;
    grid-template-columns: 70px 160px minmax(230px, 0.8fr) minmax(0, 1.45fr);
    gap: 1.4rem;
    align-items: start;
    padding: 1.7rem 0;
    border-top: 1px solid var(--line);
}

.ledger-number {
    color: var(--signal-strong);
    font-size: 0.76rem;
    font-weight: 840;
    letter-spacing: 0.12em;
}

.ledger-name {
    color: var(--ink-strong);
    font-size: 1.5rem;
    font-weight: 780;
    letter-spacing: -0.03em;
}

.ledger-summary {
    color: var(--muted);
    padding-top: 0.25rem;
}

.ledger-features {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    list-style: none;
    gap: 0.55rem 1.5rem;
}

.ledger-features li {
    position: relative;
    padding-left: 0.9rem;
    font-size: 0.84rem;
    color: var(--ink);
}

.ledger-features li::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0.62em;
    width: 4px;
    height: 4px;
    background: var(--signal);
}

.license-note {
    display: flex;
    gap: 0.9rem;
    align-items: flex-start;
    margin-top: 1.2rem;
    color: var(--muted);
    font-size: 0.9rem;
}

.license-note strong {
    color: var(--ink-strong);
}

.license-note__mark {
    flex: 0 0 auto;
    width: 9px;
    height: 9px;
    margin-top: 0.38rem;
    background: var(--signal);
    transform: rotate(45deg);
}

.linked-work {
    background: var(--inverse);
    color: var(--inverse-text);
    padding: 5.5rem max(1.5rem, calc((100vw - 1240px) / 2));
}

.section-intro--inverse {
    border-color: color-mix(in srgb, var(--inverse-muted) 28%, transparent);
}

.section-intro--inverse .section-index {
    color: var(--signal-strong);
}

.section-intro--inverse h2 {
    color: var(--inverse-text);
}

.section-intro--inverse p {
    color: var(--inverse-muted);
}

.context-chain {
    display: grid;
    grid-template-columns: 1fr 72px 1fr 72px 1fr 72px 1fr;
    align-items: center;
    margin-top: 3rem;
}

.context-item {
    min-height: 138px;
    border: 1px solid color-mix(in srgb, var(--inverse-muted) 35%, transparent);
    padding: 1.2rem;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    background: color-mix(in srgb, var(--inverse-2) 88%, transparent);
}

.context-type {
    color: var(--signal-strong);
    margin-bottom: auto;
}

.context-item strong {
    font-size: 1.08rem;
    letter-spacing: -0.02em;
}

.context-item small {
    margin-top: 0.2rem;
    color: var(--inverse-muted);
}

.context-connector {
    display: flex;
    align-items: center;
    justify-content: center;
}

.context-connector span {
    width: 100%;
    height: 1px;
    position: relative;
    background: color-mix(in srgb, var(--inverse-muted) 45%, transparent);
}

.context-connector span::after {
    content: "";
    position: absolute;
    right: -1px;
    top: -3px;
    width: 7px;
    height: 7px;
    border-top: 1px solid var(--signal-strong);
    border-right: 1px solid var(--signal-strong);
    transform: rotate(45deg);
}

.context-principles {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 2rem;
    margin-top: 2.3rem;
}

.context-principles p {
    color: var(--inverse-muted);
    font-size: 0.88rem;
}

.context-principles span {
    color: var(--signal-strong);
    font-weight: 820;
    margin-right: 0.4rem;
}

.identity-band {
    width: min(1240px, calc(100% - 3rem));
    margin: 0 auto;
    padding: 6rem 0;
    display: grid;
    grid-template-columns: 0.72fr 1.6fr;
    gap: clamp(3rem, 7vw, 7rem);
}

.identity-heading {
    border-top: 2px solid var(--ink-strong);
    padding-top: 1rem;
}

.identity-heading h2 {
    margin-top: 1rem;
}

.identity-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(280px, 0.86fr);
    gap: 3rem;
}

.identity-lead {
    color: var(--ink-strong);
    font-size: 1.3rem;
    line-height: 1.35;
    letter-spacing: -0.02em;
    margin-bottom: 1rem;
}

.identity-copy p:not(.identity-lead) {
    color: var(--muted);
}

.identity-register {
    border-top: 1px solid var(--line-strong);
}

.identity-register > div {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 1rem;
    padding: 0.92rem 0;
    border-bottom: 1px solid var(--line);
}

.identity-register span {
    color: var(--muted);
    font-size: 0.82rem;
}

.identity-register strong {
    font-size: 0.82rem;
    color: var(--ink-strong);
}

.deployment-field {
    padding: 0 0 6rem;
}

.topology {
    display: grid;
    grid-template-columns: 1fr 130px 1fr 130px 1fr;
    align-items: center;
    margin-top: 3rem;
}

.topology-stage {
    min-height: 180px;
    border: 1px solid var(--line-strong);
    padding: 1.3rem;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    position: relative;
    overflow: hidden;
    background: var(--paper-strong);
}

.topology-stage::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--signal);
}

.topology-stage--cluster::after,
.topology-stage--dc::after {
    content: "";
    position: absolute;
    inset: 24px 24px auto auto;
    width: 52px;
    height: 52px;
    border: 1px solid var(--line);
    box-shadow: -10px 10px 0 -1px var(--paper-strong), -10px 10px 0 0 var(--line);
}

.topology-stage--dc::after {
    width: 64px;
    height: 64px;
    box-shadow: -9px 9px 0 -1px var(--paper-strong), -9px 9px 0 0 var(--line), -18px 18px 0 -1px var(--paper-strong), -18px 18px 0 0 var(--line);
}

.topology-label {
    color: var(--signal-strong);
    margin-bottom: auto;
}

.topology-stage strong {
    color: var(--ink-strong);
    font-size: 1.3rem;
}

.topology-stage span {
    color: var(--muted);
    font-size: 0.84rem;
}

.topology-path {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.topology-path::before,
.topology-path::after,
.topology-path i {
    content: "";
    width: 8px;
    height: 8px;
    background: var(--line-strong);
    transform: rotate(45deg);
}

.topology-path i:nth-child(2) {
    background: var(--signal);
}

.deployment-notes {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1rem 3rem;
    margin-top: 1.4rem;
    color: var(--muted);
    font-size: 0.9rem;
}

.deployment-notes strong {
    color: var(--ink-strong);
}

.architecture-notes {
    border-top: 1px solid var(--line);
    padding: 5.5rem 0;
    display: grid;
    grid-template-columns: minmax(0, 0.9fr) minmax(420px, 1.1fr);
    gap: clamp(3rem, 7vw, 7rem);
}

.architecture-copy h2 {
    margin-top: 1rem;
}

.architecture-copy > p {
    margin-top: 1.2rem;
    color: var(--muted);
}

.architecture-caveat {
    padding-left: 1rem;
    border-left: 3px solid var(--signal);
    color: var(--ink) !important;
}

.architecture-register {
    border-top: 1px solid var(--line-strong);
}

.architecture-register > div {
    display: grid;
    grid-template-columns: 0.85fr 1.15fr;
    gap: 2rem;
    padding: 1rem 0;
    border-bottom: 1px solid var(--line);
}

.architecture-register dt {
    color: var(--muted);
    font-size: 0.82rem;
}

.architecture-register dd {
    color: var(--ink-strong);
    font-size: 0.88rem;
    font-weight: 720;
}

.closing-band {
    padding: 4.2rem 0;
    border-top: 2px solid var(--ink-strong);
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 3rem;
    align-items: end;
}

.closing-band h2 {
    max-width: 760px;
    margin-top: 0.8rem;
}

.closing-band p {
    max-width: 760px;
    margin-top: 1rem;
    color: var(--muted);
}

.closing-actions {
    margin-top: 0;
    justify-content: flex-end;
}

.site-footer {
    display: flex;
    justify-content: space-between;
    gap: 2rem;
    padding: 1.6rem 0 2.2rem;
    border-top: 1px solid var(--line);
    color: var(--muted);
    font-size: 0.78rem;
}

.site-footer nav {
    display: flex;
    flex-wrap: wrap;
    gap: 1.2rem;
}

@media (max-width: 1080px) {
    .site-rail {
        gap: 1.2rem;
        padding-inline: 1.25rem;
    }

    .rail-nav {
        gap: 1rem;
    }

    .logo-stack--rail {
        width: 150px;
    }

    .opening-layout,
    .identity-band,
    .architecture-notes {
        grid-template-columns: 1fr;
    }

    .operating-profile {
        max-width: 620px;
    }

    .context-chain {
        grid-template-columns: 1fr 40px 1fr;
        gap: 0;
    }

    .context-item:nth-of-type(5),
    .context-item:nth-of-type(7) {
        margin-top: 1rem;
    }

    .context-connector:nth-of-type(4) {
        display: none;
    }

    .context-chain .context-item:nth-child(5) {
        grid-column: 1;
    }

    .context-chain .context-connector:nth-child(6) {
        grid-column: 2;
    }

    .context-chain .context-item:nth-child(7) {
        grid-column: 3;
    }

    .topology {
        grid-template-columns: 1fr 72px 1fr 72px 1fr;
    }
}

@media (max-width: 860px) {
    .site-rail {
        grid-template-columns: auto 1fr auto;
    }

    .rail-nav {
        display: none;
    }

    .rail-actions {
        grid-column: 3;
    }

    .section-intro {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }

    .ledger-row {
        grid-template-columns: 54px 130px 1fr;
    }

    .ledger-features {
        grid-column: 2 / -1;
        padding-top: 0.8rem;
    }

    .identity-layout {
        grid-template-columns: 1fr;
    }

    .topology {
        grid-template-columns: 1fr;
        gap: 0.8rem;
    }

    .topology-path {
        min-height: 44px;
        transform: rotate(90deg);
    }

    .deployment-notes,
    .context-principles {
        grid-template-columns: 1fr;
    }

    .closing-band {
        grid-template-columns: 1fr;
        align-items: start;
    }

    .closing-actions {
        justify-content: flex-start;
    }
}

@media (max-width: 640px) {
    :root {
        --rail-height: 60px;
    }

    .site-rail {
        padding-inline: 0.9rem;
    }

    .logo-stack--rail {
        width: 126px;
    }

    .theme-switch #themeBtnText,
    .rail-contact {
        display: none;
    }

    .opening-statement,
    .platform-ledger,
    .identity-band,
    .deployment-field,
    .architecture-notes,
    .closing-band,
    .site-footer {
        width: min(100% - 2rem, 1240px);
    }

    .opening-statement {
        padding: 3.4rem 0 4rem;
    }

    .logo-stack--opening {
        margin-bottom: 1.5rem;
    }

    .opening-title {
        font-size: clamp(2.2rem, 12vw, 3.45rem);
    }

    .opening-actions .action,
    .closing-actions .action {
        width: 100%;
    }

    .platform-ledger,
    .identity-band,
    .deployment-field,
    .architecture-notes {
        padding-bottom: 4rem;
    }

    .ledger-row {
        grid-template-columns: 42px 1fr;
        gap: 0.7rem 1rem;
    }

    .ledger-name {
        font-size: 1.25rem;
    }

    .ledger-summary,
    .ledger-features {
        grid-column: 2;
    }

    .ledger-features {
        grid-template-columns: 1fr;
    }

    .linked-work {
        padding: 4rem 1rem;
    }

    .context-chain {
        display: flex;
        flex-direction: column;
        gap: 0;
    }

    .context-item {
        width: 100%;
        min-height: 120px;
    }

    .context-connector {
        width: 1px;
        height: 38px;
    }

    .context-connector span {
        width: 1px;
        height: 100%;
    }

    .context-connector span::after {
        right: -3px;
        top: auto;
        bottom: -1px;
        transform: rotate(135deg);
    }

    .architecture-register > div {
        grid-template-columns: 1fr;
        gap: 0.3rem;
    }

    .site-footer {
        flex-direction: column;
    }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        scroll-behavior: auto !important;
        transition: none !important;
        animation: none !important;
    }
}