:root {
    --ink: #172033;
    --muted: #5f6b7d;
    --surface: #ffffff;
    --surface-soft: #f5f7fb;
    --line: #dfe5ee;
    --accent: #2456d6;
    --accent-dark: #173b91;
    --accent-soft: #eaf0ff;
    --success: #16785d;
    --max-width: 1160px;
    --shadow: 0 16px 40px rgba(23, 32, 51, 0.09);
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    color: var(--ink);
    background: var(--surface);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.65;
    overflow-x: hidden;
}

body.theme-quantum {
    --accent: #6844c6;
    --accent-dark: #3e277d;
    --accent-soft: #f0ecff;
}

body.theme-isac {
    --accent: #087d93;
    --accent-dark: #075367;
    --accent-soft: #e6f7fa;
}

body.theme-ntn {
    --accent: #28619f;
    --accent-dark: #183e6b;
    --accent-soft: #e9f2fb;
}

body.theme-optical {
    --accent: #b85817;
    --accent-dark: #7b360d;
    --accent-soft: #fff0e5;
}

body.theme-6g {
    --accent: #304fc4;
    --accent-dark: #1c317d;
    --accent-soft: #eaedff;
}

a {
    color: var(--accent);
}

a:hover {
    color: var(--accent-dark);
}

a:focus-visible,
button:focus-visible {
    outline: 3px solid color-mix(in srgb, var(--accent) 45%, white);
    outline-offset: 3px;
}

.interest-container {
    width: min(calc(100% - 40px), var(--max-width));
    min-width: 0;
    margin: 0 auto;
}

.interest-site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    border-bottom: 1px solid rgba(223, 229, 238, 0.9);
    background: rgba(255, 255, 255, 0.94);
    -webkit-backdrop-filter: blur(14px);
    backdrop-filter: blur(14px);
}

.interest-nav {
    min-height: 72px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
}

.interest-brand {
    color: var(--ink);
    font-size: 1.08rem;
    font-weight: 750;
    letter-spacing: -0.02em;
    text-decoration: none;
    white-space: nowrap;
}

.interest-nav-links {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 1.35rem;
    margin: 0;
    padding: 0;
    list-style: none;
}

.interest-nav-links a {
    color: var(--muted);
    font-size: 0.94rem;
    font-weight: 650;
    text-decoration: none;
}

.interest-nav-links a[aria-current="page"],
.interest-nav-links a:hover {
    color: var(--accent);
}

.topic-hero {
    position: relative;
    overflow: hidden;
    border-bottom: 1px solid var(--line);
    background:
        radial-gradient(circle at 85% 15%, color-mix(in srgb, var(--accent) 18%, transparent) 0, transparent 34%),
        linear-gradient(145deg, #f9fbff 0%, var(--accent-soft) 100%);
}

.topic-hero::after {
    position: absolute;
    right: -120px;
    bottom: -180px;
    width: 420px;
    height: 420px;
    border: 1px solid color-mix(in srgb, var(--accent) 20%, transparent);
    border-radius: 50%;
    content: "";
}

.topic-hero-inner {
    position: relative;
    z-index: 1;
    padding: 3.5rem 0 4.5rem;
}

.breadcrumb {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.45rem;
    margin-bottom: 2.7rem;
    color: var(--muted);
    font-size: 0.9rem;
}

.breadcrumb a {
    color: inherit;
    text-decoration: none;
}

.breadcrumb a:hover {
    color: var(--accent);
}

.topic-hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.55fr) minmax(280px, 0.75fr);
    gap: clamp(2rem, 5vw, 5rem);
    align-items: center;
}

.topic-hero-grid > *,
.topic-hero-copy,
.status-panel {
    min-width: 0;
}

.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 0.55rem;
    margin: 0 0 1rem;
    color: var(--accent-dark);
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.12em;
    line-height: 1.3;
    text-transform: uppercase;
}

.eyebrow::before {
    width: 24px;
    height: 2px;
    background: var(--accent);
    content: "";
}

.topic-hero h1 {
    max-width: 850px;
    margin: 0;
    font-size: clamp(2.45rem, 6vw, 4.8rem);
    letter-spacing: -0.055em;
    line-height: 1.04;
}

.topic-hero-copy > p:not(.eyebrow) {
    max-width: 790px;
    margin: 1.4rem 0 0;
    color: #3e4b60;
    font-size: clamp(1.06rem, 2vw, 1.25rem);
}

.topic-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.65rem;
    margin-top: 1.65rem;
}

.topic-tag {
    border: 1px solid color-mix(in srgb, var(--accent) 28%, white);
    border-radius: 999px;
    padding: 0.42rem 0.78rem;
    color: var(--accent-dark);
    background: rgba(255, 255, 255, 0.76);
    font-size: 0.84rem;
    font-weight: 700;
}

.status-panel {
    position: relative;
    border: 1px solid color-mix(in srgb, var(--accent) 25%, white);
    border-radius: 20px;
    padding: 1.5rem;
    background: rgba(255, 255, 255, 0.84);
    box-shadow: var(--shadow);
}

.status-label {
    display: inline-block;
    margin-bottom: 0.75rem;
    border-radius: 999px;
    padding: 0.38rem 0.72rem;
    color: #fff;
    background: var(--accent);
    font-size: 0.72rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.status-panel h2 {
    margin: 0 0 0.65rem;
    font-size: 1.18rem;
    line-height: 1.35;
}

.status-panel p {
    margin: 0;
    color: var(--muted);
    font-size: 0.96rem;
}

.content-section {
    padding: 5rem 0;
}

.content-section.alt {
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
    background: var(--surface-soft);
}

.section-heading {
    max-width: 760px;
    margin-bottom: 2.3rem;
}

.section-kicker {
    margin: 0 0 0.55rem;
    color: var(--accent);
    font-size: 0.77rem;
    font-weight: 800;
    letter-spacing: 0.11em;
    text-transform: uppercase;
}

.section-heading h2 {
    margin: 0;
    font-size: clamp(1.9rem, 4vw, 2.8rem);
    letter-spacing: -0.035em;
    line-height: 1.15;
}

.section-heading p {
    margin: 0.8rem 0 0;
    color: var(--muted);
    font-size: 1.04rem;
}

.evidence-strip {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    overflow: hidden;
    margin-top: -1.3rem;
    border: 1px solid var(--line);
    border-radius: 18px;
    background: var(--surface);
    box-shadow: 0 10px 26px rgba(23, 32, 51, 0.06);
}

.evidence-item {
    padding: 1.45rem 1.55rem;
}

.evidence-item + .evidence-item {
    border-left: 1px solid var(--line);
}

.evidence-item span {
    display: block;
    margin-bottom: 0.35rem;
    color: var(--accent);
    font-size: 0.73rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.evidence-item strong {
    display: block;
    font-size: 1.02rem;
    line-height: 1.45;
}

.method-grid,
.topic-card-grid,
.resource-grid,
.hub-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.2rem;
}

.method-card,
.topic-card,
.resource-card,
.hub-card {
    border: 1px solid var(--line);
    border-radius: 18px;
    padding: 1.45rem;
    background: var(--surface);
}

.method-number {
    display: inline-grid;
    width: 2.15rem;
    height: 2.15rem;
    place-items: center;
    margin-bottom: 1rem;
    border-radius: 10px;
    color: #fff;
    background: var(--accent);
    font-size: 0.85rem;
    font-weight: 800;
}

.method-card h3,
.topic-card h3,
.resource-card h3,
.hub-card h2 {
    margin: 0;
    font-size: 1.14rem;
    line-height: 1.4;
}

.method-card p,
.topic-card p,
.resource-card p,
.hub-card p {
    margin: 0.55rem 0 0;
    color: var(--muted);
}

.two-column {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.3rem;
}

.list-panel {
    border: 1px solid var(--line);
    border-radius: 20px;
    padding: clamp(1.4rem, 3vw, 2rem);
    background: var(--surface);
}

.list-panel h3 {
    margin: 0 0 1rem;
    font-size: 1.3rem;
}

.professional-list {
    display: grid;
    gap: 0.8rem;
    margin: 0;
    padding: 0;
    list-style: none;
}

.professional-list li {
    position: relative;
    padding-left: 1.45rem;
    color: #3d4a5f;
}

.professional-list li::before {
    position: absolute;
    top: 0.64em;
    left: 0;
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--accent);
    content: "";
}

.roadmap {
    position: relative;
    display: grid;
    gap: 1rem;
}

.roadmap-step {
    display: grid;
    grid-template-columns: 130px minmax(0, 1fr);
    gap: 1.4rem;
    align-items: start;
    border: 1px solid var(--line);
    border-radius: 18px;
    padding: 1.35rem;
    background: var(--surface);
}

.roadmap-phase {
    border-radius: 10px;
    padding: 0.55rem 0.7rem;
    color: var(--accent-dark);
    background: var(--accent-soft);
    font-size: 0.76rem;
    font-weight: 800;
    letter-spacing: 0.06em;
    text-align: center;
    text-transform: uppercase;
}

.roadmap-step h3 {
    margin: 0;
    font-size: 1.13rem;
}

.roadmap-step p {
    margin: 0.4rem 0 0;
    color: var(--muted);
}

.resource-card {
    position: relative;
    display: flex;
    flex-direction: column;
    min-height: 230px;
    transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.resource-card:hover {
    border-color: color-mix(in srgb, var(--accent) 45%, white);
    box-shadow: var(--shadow);
    transform: translateY(-3px);
}

.resource-type {
    align-self: flex-start;
    margin-bottom: 1rem;
    border-radius: 999px;
    padding: 0.35rem 0.68rem;
    color: var(--accent-dark);
    background: var(--accent-soft);
    font-size: 0.72rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.resource-card .resource-note {
    margin-bottom: 1.2rem;
    font-size: 0.92rem;
}

.resource-link {
    display: inline-flex;
    align-items: center;
    gap: 0.45rem;
    margin-top: auto;
    font-size: 0.93rem;
    font-weight: 750;
    text-decoration: none;
}

.resource-link::after {
    content: "↗";
}

.resource-context {
    margin: -1rem 0 2rem;
    border-left: 3px solid var(--accent);
    padding: 0.85rem 1rem;
    color: var(--muted);
    background: var(--accent-soft);
    font-size: 0.94rem;
}

.bridge-card {
    display: grid;
    grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr);
    gap: 2rem;
    align-items: start;
    border: 1px solid color-mix(in srgb, var(--accent) 24%, white);
    border-radius: 22px;
    padding: clamp(1.5rem, 4vw, 2.6rem);
    background: linear-gradient(145deg, var(--accent-soft), #fff 72%);
}

.bridge-card h2 {
    margin: 0;
    font-size: clamp(1.7rem, 3vw, 2.25rem);
    letter-spacing: -0.03em;
    line-height: 1.2;
}

.bridge-card p {
    margin: 0;
    color: #3d4a5f;
}

.bridge-points {
    display: grid;
    gap: 0.75rem;
    margin-top: 1.15rem;
}

.bridge-point {
    border-radius: 12px;
    padding: 0.85rem 1rem;
    background: rgba(255, 255, 255, 0.8);
}

.bridge-point strong {
    display: block;
    margin-bottom: 0.18rem;
}

.hub-hero .topic-hero-grid {
    grid-template-columns: minmax(0, 1.3fr) minmax(300px, 0.8fr);
}

.hub-card {
    display: flex;
    flex-direction: column;
    min-height: 285px;
    transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.hub-card:hover {
    border-color: color-mix(in srgb, var(--card-accent, var(--accent)) 42%, white);
    box-shadow: var(--shadow);
    transform: translateY(-4px);
}

.hub-card.quantum { --card-accent: #6844c6; }
.hub-card.isac { --card-accent: #087d93; }
.hub-card.ntn { --card-accent: #28619f; }
.hub-card.optical { --card-accent: #b85817; }
.hub-card.future { --card-accent: #304fc4; }

.hub-card-status {
    display: inline-block;
    align-self: flex-start;
    margin-bottom: 1.1rem;
    border-radius: 999px;
    padding: 0.34rem 0.66rem;
    color: var(--card-accent, var(--accent));
    background: color-mix(in srgb, var(--card-accent, var(--accent)) 10%, white);
    font-size: 0.71rem;
    font-weight: 800;
    letter-spacing: 0.075em;
    text-transform: uppercase;
}

.hub-card ul {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
    margin: 1rem 0 1.3rem;
    padding: 0;
    list-style: none;
}

.hub-card li {
    border-radius: 999px;
    padding: 0.3rem 0.58rem;
    color: #4b5768;
    background: var(--surface-soft);
    font-size: 0.78rem;
    font-weight: 650;
}

.hub-card .resource-link {
    color: var(--card-accent, var(--accent));
}

.hub-card .resource-link::after {
    content: "→";
}

.hub-card.featured {
    grid-column: 1 / -1;
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    min-height: auto;
    align-items: center;
    gap: 1.2rem;
}

.hub-card.featured .resource-link {
    align-self: center;
    margin: 0;
}

.integrity-note {
    border: 1px solid #b9dfd3;
    border-radius: 18px;
    padding: 1.3rem 1.45rem;
    color: #214f42;
    background: #effaf6;
}

.integrity-note strong {
    display: block;
    margin-bottom: 0.35rem;
    color: var(--success);
}

.topic-switcher {
    padding: 2.7rem 0;
    border-top: 1px solid var(--line);
    background: var(--surface-soft);
}

.topic-switcher-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.topic-switcher p {
    margin: 0;
    color: var(--muted);
}

.button-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.7rem;
}

.interest-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--accent);
    border-radius: 10px;
    padding: 0.72rem 1rem;
    color: #fff;
    background: var(--accent);
    font-size: 0.9rem;
    font-weight: 750;
    text-decoration: none;
}

.interest-button.secondary {
    color: var(--accent);
    background: transparent;
}

.interest-button:hover {
    color: #fff;
    background: var(--accent-dark);
}

.interest-button.secondary:hover {
    color: var(--accent-dark);
    background: var(--accent-soft);
}

.interest-footer {
    padding: 2rem 0;
    color: #d3d8e2;
    background: var(--ink);
}

.interest-footer-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.interest-footer p {
    margin: 0;
}

.interest-footer a {
    color: #fff;
    font-weight: 650;
}

.skip-link {
    position: fixed;
    top: 0.6rem;
    left: 0.6rem;
    z-index: 100;
    padding: 0.65rem 0.9rem;
    color: #fff;
    background: var(--ink);
    transform: translateY(-160%);
}

.skip-link:focus {
    transform: translateY(0);
}

@media (max-width: 860px) {
    .interest-nav {
        align-items: flex-start;
        flex-direction: column;
        padding: 1rem 0;
    }

    .interest-nav-links {
        width: 100%;
        min-width: 0;
        max-width: 100%;
        justify-content: flex-start;
        overflow-x: auto;
        padding-bottom: 0.15rem;
    }

    .topic-hero-grid,
    .hub-hero .topic-hero-grid,
    .bridge-card {
        grid-template-columns: 1fr;
    }

    .status-panel {
        max-width: 620px;
    }

}

@media (max-width: 680px) {
    .interest-container {
        width: min(calc(100% - 28px), var(--max-width));
    }

    .topic-hero-inner {
        padding: 2.5rem 0 3.3rem;
    }

    .breadcrumb {
        margin-bottom: 1.9rem;
    }

    .topic-hero h1 {
        font-size: clamp(2.05rem, 10.8vw, 3rem);
        overflow-wrap: anywhere;
    }

    .topic-hero-copy > p:not(.eyebrow) {
        overflow-wrap: anywhere;
    }

    .content-section {
        padding: 3.6rem 0;
    }

    .method-grid,
    .topic-card-grid,
    .resource-grid,
    .hub-grid,
    .two-column,
    .evidence-strip {
        grid-template-columns: 1fr;
    }

    .evidence-item + .evidence-item {
        border-top: 1px solid var(--line);
        border-left: 0;
    }

    .roadmap-step {
        grid-template-columns: 1fr;
        gap: 0.85rem;
    }

    .roadmap-phase {
        justify-self: start;
    }

    .hub-card.featured {
        grid-column: auto;
        grid-template-columns: 1fr;
    }

    .topic-switcher-inner,
    .interest-footer-inner {
        align-items: flex-start;
        flex-direction: column;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        transition-duration: 0.01ms !important;
    }
}

@media print {
    .interest-site-header,
    .topic-switcher,
    .interest-footer,
    .skip-link {
        display: none;
    }

    .topic-hero,
    .content-section,
    .content-section.alt {
        padding: 1.5rem 0;
        border: 0;
        background: #fff;
    }

    .resource-card,
    .method-card,
    .list-panel,
    .roadmap-step,
    .bridge-card,
    .hub-card {
        break-inside: avoid;
        box-shadow: none;
    }
}