.technical-bg {
    background-image:
        linear-gradient(rgba(233, 227, 214, 0.08) 1px, transparent 1px),
        linear-gradient(90deg, rgba(233, 227, 214, 0.08) 1px, transparent 1px);
    background-size: 40px 40px;
}

.bg-system {
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
    overflow: hidden;
    perspective: 1000px;
    background:
        radial-gradient(ellipse 80% 60% at 50% 40%, rgba(194, 173, 130, 0.08), transparent 70%),
        radial-gradient(ellipse 60% 50% at 20% 80%, rgba(140, 136, 168, 0.05), transparent 60%);
}

.bg-plane {
    position: absolute;
    inset: -5%;
    width: 110%;
    height: 110%;
    transform-style: preserve-3d;
    transition: transform 0.5s ease-out, opacity 0.5s ease-out;
    will-change: transform, opacity;
}

.plane-grid {
    transform: translateZ(-200px) translateY(calc(var(--scroll-progress) * 100px));
    opacity: 0.58;
}

.plane-shell {
    position: absolute;
    transform: translateZ(-100px) translateY(calc(var(--scroll-progress) * 50px));
    border-left: 1px solid rgba(233, 227, 214, 0.14);
    border-right: 1px solid rgba(233, 227, 214, 0.14);
    width: 60%;
    left: 20%;
    background: linear-gradient(180deg, rgba(194, 173, 130, 0.03) 0%, transparent 30%, transparent 70%, rgba(194, 173, 130, 0.03) 100%);
}

.plane-rail {
    transform: translateZ(-50px) translateY(calc(var(--scroll-progress) * 20px));
    display: flex;
    justify-content: center;
    opacity: 1;
}

.rail-track {
    width: 2px;
    height: 100%;
    background: linear-gradient(to bottom, transparent, rgba(194, 173, 130, 0.45) 15%, rgba(194, 173, 130, 0.45) 85%, transparent);
    position: relative;
    box-shadow: 0 0 24px rgba(194, 173, 130, 0.15);
}

.route-bead {
    position: absolute;
    top: calc(var(--scroll-progress) * 100%);
    left: -4px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #C2AD82;
    box-shadow: 0 0 16px rgba(194, 173, 130, 0.8), 0 0 32px rgba(194, 173, 130, 0.35);
    transition: top 0.1s linear;
    will-change: top;
}

.chamber-overlay {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.8s ease-in-out;
}

.bg-system[data-chapter="0"] .chamber-hero { opacity: 1; }
.bg-system[data-chapter="1"] .chamber-intake { opacity: 1; }
.bg-system[data-chapter="2"] .chamber-quote { opacity: 1; }
.bg-system[data-chapter="3"] .chamber-execution { opacity: 1; }
.bg-system[data-chapter="4"] .chamber-vault { opacity: 1; }
.bg-system[data-chapter="5"] .chamber-mica { opacity: 1; }
.bg-system[data-chapter="6"] .chamber-settle { opacity: 1; }
.bg-system[data-chapter="7"] .chamber-report { opacity: 1; }
.bg-system[data-chapter="8"] .chamber-cta { opacity: 1; }

.trace-path {
    stroke-dasharray: 2000;
    stroke-dashoffset: 2000;
    transition: stroke-dashoffset 1.5s ease-out;
}

.bg-system[data-chapter="0"] .chamber-hero .trace-path,
.bg-system[data-chapter="1"] .chamber-intake .trace-path,
.bg-system[data-chapter="2"] .chamber-quote .trace-path,
.bg-system[data-chapter="3"] .chamber-execution .trace-path,
.bg-system[data-chapter="4"] .chamber-vault .trace-path,
.bg-system[data-chapter="5"] .chamber-mica .trace-path,
.bg-system[data-chapter="6"] .chamber-settle .trace-path,
.bg-system[data-chapter="7"] .chamber-report .trace-path,
.bg-system[data-chapter="8"] .chamber-cta .trace-path {
    stroke-dashoffset: 0;
}

.tech-annotation {
    position: absolute;
    font-family: 'Public Sans', sans-serif;
    font-size: 8px;
    color: #C2AD82;
    text-transform: uppercase;
    letter-spacing: 0.2em;
    opacity: 0;
    transition: opacity 0.3s;
}

.bg-system[data-chapter="0"] .chamber-hero .tech-annotation,
.bg-system[data-chapter="1"] .chamber-intake .tech-annotation,
.bg-system[data-chapter="2"] .chamber-quote .tech-annotation,
.bg-system[data-chapter="3"] .chamber-execution .tech-annotation,
.bg-system[data-chapter="4"] .chamber-vault .tech-annotation,
.bg-system[data-chapter="5"] .chamber-mica .tech-annotation,
.bg-system[data-chapter="6"] .chamber-settle .tech-annotation,
.bg-system[data-chapter="7"] .chamber-report .tech-annotation,
.bg-system[data-chapter="8"] .chamber-cta .tech-annotation {
    opacity: 0.92;
}

.bg-system .chamber-overlay svg .trace-path {
    filter: drop-shadow(0 0 1px rgba(194, 173, 130, 0.25));
}

.bg-system > .bg-plane:last-child {
    transform-style: preserve-3d;
}

.chamber-overlay > svg[class*="layer-"],
.chamber-overlay > div[class*="layer-"] {
    position: absolute;
    left: 50%;
    top: 50%;
    margin: 0;
}

.chamber-overlay > svg.layer-deep,
.chamber-overlay > div.layer-deep {
    transform: translate(-50%, -50%) translateZ(-150px) scale(1.1);
}

.chamber-overlay > svg.layer-mid,
.chamber-overlay > div.layer-mid {
    transform: translate(-50%, -50%) translateZ(-50px) scale(1.05);
}

.chamber-overlay > svg.layer-front,
.chamber-overlay > div.layer-front {
    transform: translate(-50%, -50%) translateZ(50px) scale(0.95);
}