.skip-link {
    position: fixed;
    top: var(--space-4);
    left: var(--space-4);
    z-index: 50;
    transform: translateY(-160%);
    background: var(--text-primary);
    color: var(--ink);
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-sm);
    font-weight: 600;
    text-decoration: none;
}

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

.mono,
.section-kicker,
.meta {
    font-family: 'JetBrains Mono', monospace;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    font-size: var(--text-2xs);
}

.mono,
.section-kicker {
    color: var(--accent-soft);
}

.site-nav a {
    display: inline-flex;
    min-height: 2.5rem;
    align-items: center;
    color: inherit;
    text-decoration: none;
    font-size: var(--text-xs);
    font-weight: 600;
}

.site-nav > a {
    color: var(--text-primary);
    font-family: 'JetBrains Mono', monospace;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.site-nav div {
    padding: 0.26rem;
    border: 1px solid rgba(245, 241, 234, 0.12);
    border-radius: 999px;
    background: rgba(5, 5, 5, 0.74);
    box-shadow: 0 18px 40px rgba(0, 0, 0, 0.28);
    backdrop-filter: blur(18px);
}

.site-nav div a {
    padding: 0 var(--space-3);
    border-radius: 999px;
    transition:
        color var(--duration-fast) var(--ease-standard),
        background var(--duration-fast) var(--ease-standard);
}

.site-nav div a:hover,
.site-nav div a.is-current {
    color: var(--text-primary);
    background: rgba(245, 241, 234, 0.09);
}

h1,
h2,
h3,
h4,
p {
    overflow-wrap: anywhere;
}

h1 {
    font-size: var(--text-hero);
    font-weight: 600;
    line-height: 0.92;
    letter-spacing: 0;
    margin: var(--space-4) 0 var(--space-5);
}

h2 {
    font-size: var(--text-2xl);
    font-weight: 500;
    line-height: 1.04;
    letter-spacing: 0;
}

.intro-text {
    max-width: 640px;
    color: var(--text-secondary);
    font-size: var(--text-lg);
    font-weight: 300;
    line-height: 1.55;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3);
    margin-top: var(--space-7);
}

.hero-actions a,
.contact-link {
    position: relative;
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    min-height: 2.75rem;
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
}

.hero-actions a {
    padding: 0 var(--space-4);
    border: 1px solid var(--border-strong);
    border-radius: 999px;
    background: rgba(16, 16, 15, 0.6);
    transition:
        border-color var(--duration-fast) var(--ease-standard),
        background var(--duration-fast) var(--ease-standard),
        transform var(--duration-fast) var(--ease-standard);
}

.hero-actions a::after,
.contact-link::after {
    content: '';
    width: 0.46rem;
    height: 0.46rem;
    border-top: 1px solid currentColor;
    border-right: 1px solid currentColor;
    transform: rotate(45deg);
}

.hero-actions a:hover {
    transform: translateY(-2px);
    border-color: rgba(231, 77, 61, 0.82);
    background: rgba(231, 77, 61, 0.12);
}

.system-card {
    position: relative;
    overflow: hidden;
    min-height: 620px;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background:
        linear-gradient(150deg, rgba(231, 77, 61, 0.12), transparent 34%),
        linear-gradient(20deg, rgba(143, 183, 176, 0.12), transparent 42%),
        var(--surface);
    box-shadow: var(--shadow);
}

.system-card::before,
.system-card::after {
    content: '';
    position: absolute;
    pointer-events: none;
}

.system-card::before {
    inset: var(--space-4);
    border: 1px solid rgba(245, 241, 234, 0.07);
    border-radius: var(--radius-sm);
}

.system-card::after {
    width: 32%;
    height: 1px;
    right: var(--space-5);
    top: 50%;
    background: var(--accent);
    box-shadow: 0 0 32px rgba(231, 77, 61, 0.5);
}

.system-card__header {
    position: relative;
    z-index: 1;
    display: flex;
    justify-content: space-between;
    padding: var(--space-5);
    color: var(--text-muted);
    font-family: 'JetBrains Mono', monospace;
}

.system-card__header .mono {
    margin: 0;
}

.signal-map {
    position: relative;
    z-index: 1;
    width: min(88%, 430px);
    margin: var(--space-4) auto 0;
    overflow: hidden;
}

.signal-map svg {
    overflow: hidden;
}

.trace {
    fill: none;
    stroke: rgba(245, 241, 234, 0.34);
    stroke-width: 1.5;
    stroke-linecap: round;
}

.trace-two {
    stroke: rgba(143, 183, 176, 0.62);
}

.trace-three {
    stroke: rgba(231, 77, 61, 0.72);
}

.node {
    fill: var(--bg);
    stroke: var(--text-primary);
    stroke-width: 2;
}

.node-b,
.node-d,
.node-f {
    stroke: var(--accent);
}

.signal-list {
    position: absolute;
    left: var(--space-5);
    right: var(--space-5);
    bottom: var(--space-5);
    z-index: 1;
    display: grid;
    gap: var(--space-3);
}

.signal-list div {
    display: grid;
    grid-template-columns: 5rem 1fr;
    gap: var(--space-3);
    padding-top: var(--space-3);
    border-top: 1px solid rgba(245, 241, 234, 0.11);
}

.signal-list dt {
    color: var(--text-primary);
    font-weight: 600;
}

.signal-list dd {
    color: var(--text-secondary);
    font-size: var(--text-sm);
}

.section-kicker {
    margin-bottom: var(--space-4);
}

.section-intro p {
    color: var(--text-secondary);
    font-size: var(--text-md);
    line-height: 1.6;
}

.case-files {
    display: grid;
    gap: var(--space-4);
}

.case-file {
    border-top: 1px solid var(--border-strong);
    background: linear-gradient(180deg, rgba(23, 22, 21, 0.86), rgba(16, 16, 15, 0.46));
}

.case-file__toggle {
    display: grid;
    grid-template-columns: 4.5rem 1fr 2rem;
    gap: var(--space-4);
    align-items: center;
    width: 100%;
    min-height: 7rem;
    padding: var(--space-5) 0;
    text-align: left;
}

.case-file__index {
    align-self: stretch;
    display: grid;
    place-items: center;
    color: var(--accent);
    font-family: 'JetBrains Mono', monospace;
    font-size: var(--text-xs);
}

.meta {
    display: block;
    color: var(--accent-soft);
    margin-bottom: var(--space-2);
}

.case-file__title {
    display: block;
    color: var(--text-primary);
    font-size: var(--text-xl);
    line-height: 1.1;
    font-weight: 500;
}

.case-file__mark {
    position: relative;
    width: 1.5rem;
    height: 1.5rem;
}

.case-file__mark::before,
.case-file__mark::after {
    content: '';
    position: absolute;
    inset: 50% auto auto 50%;
    width: 1.1rem;
    height: 1px;
    background: var(--text-primary);
    transform: translate(-50%, -50%);
    transition: transform var(--duration-fast) var(--ease-standard);
}

.case-file__mark::after {
    transform: translate(-50%, -50%) rotate(90deg);
}

.case-file.is-open .case-file__mark::after {
    transform: translate(-50%, -50%) rotate(0deg);
}

.case-file__body {
    display: grid;
    grid-template-columns: 4.5rem minmax(0, 720px);
    gap: var(--space-4);
    padding: 0 0 var(--space-6);
}

.case-file__body::before {
    content: '';
    justify-self: center;
    width: 1px;
    background: linear-gradient(var(--accent), transparent);
}

.case-file__body p {
    grid-column: 2;
    color: var(--text-secondary);
    font-size: var(--text-base);
    line-height: 1.72;
}

.case-file__body p + p {
    margin-top: var(--space-3);
}

.stack-board {
    display: grid;
    gap: var(--space-4);
}

.stack-panel {
    position: relative;
    overflow: hidden;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: rgba(16, 16, 15, 0.82);
    transition:
        border-color var(--duration-base) var(--ease-standard),
        background var(--duration-base) var(--ease-standard),
        transform var(--duration-fast) var(--ease-standard);
}

.stack-panel::before {
    content: '';
    position: absolute;
    inset: 0;
    width: 0.24rem;
    background: var(--text-muted);
    opacity: 0.45;
    transition:
        background var(--duration-base) var(--ease-standard),
        opacity var(--duration-base) var(--ease-standard);
}

.stack-panel[data-accent='desktop']::before {
    background: var(--accent-cool);
}

.stack-panel[data-accent='server']::before {
    background: var(--accent-soft);
}

.stack-panel[data-accent='local-ai']::before {
    background: var(--accent);
}

.stack-panel:hover {
    transform: translateY(-2px);
}

.stack-panel.is-active {
    border-color: rgba(245, 241, 234, 0.24);
    background: linear-gradient(135deg, rgba(245, 241, 234, 0.08), rgba(16, 16, 15, 0.9));
}

.stack-panel.is-active::before {
    opacity: 1;
}

.stack-panel__button {
    display: grid;
    grid-template-columns: 3rem 1fr;
    gap: var(--space-4);
    align-items: center;
    width: 100%;
    padding: var(--space-5);
    text-align: left;
}

.stack-panel__icon {
    display: grid;
    place-items: center;
    width: 3rem;
    height: 3rem;
    border: 1px solid rgba(245, 241, 234, 0.14);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.035);
}

.stack-panel__title,
.stack-panel__meta {
    display: block;
}

.stack-panel__title {
    color: var(--text-primary);
    font-weight: 600;
    line-height: 1.25;
}

.stack-panel__meta {
    margin-top: var(--space-2);
    color: var(--text-muted);
    font-family: 'JetBrains Mono', monospace;
    font-size: var(--text-xs);
    line-height: 1.45;
}

.stack-panel__body {
    padding: 0 var(--space-5) var(--space-5) calc(var(--space-5) + 4rem);
}

.stack-panel__body p {
    max-width: 620px;
    color: var(--text-secondary);
    line-height: 1.72;
}

.contact-link {
    font-size: var(--text-lg);
    margin-top: var(--space-2);
}

.contact-link:hover {
    color: var(--accent-soft);
}

.footer-note {
    color: var(--text-muted);
    font-size: var(--text-xs);
    font-family: 'JetBrains Mono', monospace;
}

a:focus-visible,
button:focus-visible {
    outline: 2px solid var(--accent-soft);
    outline-offset: 4px;
    border-radius: var(--radius-sm);
}

@media (max-width: 980px) {
    .system-card {
        min-height: 560px;
    }

    .section-intro p,
    .sticky-intro p {
        max-width: 680px;
        margin-top: var(--space-4);
    }
}

@media (max-width: 640px) {
    .site-nav > a {
        display: none;
    }

    .site-nav div {
        width: 100%;
        justify-content: space-between;
    }

    .site-nav div a {
        flex: 1;
        justify-content: center;
        padding: 0 var(--space-2);
    }

    .hero-copy,
    .intro-text,
    .system-card,
    .section-intro,
    .section-intro p {
        max-width: 100%;
        min-width: 0;
    }

    .intro-text {
        width: 100%;
    }

    .intro-text {
        font-size: var(--text-md);
    }

    .hero-actions {
        display: grid;
    }

    .hero-actions a {
        justify-content: space-between;
    }

    .system-card {
        min-height: 520px;
    }

    .system-card__header,
    .signal-list {
        left: var(--space-4);
        right: var(--space-4);
    }

    .signal-list div {
        grid-template-columns: 1fr;
        gap: var(--space-1);
    }

    .case-file__toggle {
        grid-template-columns: 2.5rem 1fr 1.5rem;
        gap: var(--space-3);
    }

    .case-file__title {
        font-size: var(--text-lg);
    }

    .case-file__body {
        grid-template-columns: 2.5rem minmax(0, 1fr);
        gap: var(--space-3);
    }

    .stack-panel__button {
        grid-template-columns: 2.75rem 1fr;
        padding: var(--space-4);
    }

    .stack-panel__icon {
        width: 2.75rem;
        height: 2.75rem;
    }

    .stack-panel__body {
        padding: 0 var(--space-4) var(--space-4);
    }

    .footer-note {
        margin-top: var(--space-5);
    }
}