hdr-explainer {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 32px;
    align-items: start;
    background: var(--text);
    border-radius: var(--radius);
    padding: 32px 36px;
}

.hdr-explainer-text {
    display: grid;
    gap: 10px;
}

.hdr-explainer-text h3 {
    font-size: 18px;
    font-weight: 700;
    color: #fff;
}

.hdr-explainer-text p {
    font-size: 14px;
    color: rgba(255,255,255,0.6);
    line-height: 1.7;
}

.hdr-explainer-text strong { color: #fff; }

.hdr-explainer-diagram {
    display: grid;
    align-items: center;
    gap: 6px;
    min-width: 160px;
}

.hdr-layer {
    width: 100%;
    border-radius: 10px;
    padding: 12px 14px;
    text-align: center;
}

.hdr-layer-sdr    { background: rgba(255,255,255,0.08); border: 1px solid rgba(255,255,255,0.15); }
.hdr-layer-map    { background: rgba(26,143,255,0.2);   border: 1px solid rgba(26,143,255,0.4); }
.hdr-layer-result { background: rgba(255,214,10,0.15);  border: 1px solid rgba(255,214,10,0.4); }

.hdr-layer-label {
    display: block;
    font-size: 12px;
    font-weight: 700;
    color: #fff;
    margin-bottom: 2px;
}

.hdr-layer-sub {
    display: block;
    font-size: 11px;
    color: rgba(255,255,255,0.5);
    line-height: 1.4;
}

.hdr-layer-plus,
.hdr-layer-equals {
    font-size: 16px;
    font-weight: 700;
    color: rgba(255,255,255,0.3);
    line-height: 1;
}

/* ── HDR format cards ── */
concept-pair.hdr-formats { --card-padding: 20px 22px; }

concept-pair.hdr-formats .card-body {
    display: grid;
    gap: 14px;
}

.hdr-format-item { display: grid; gap: 3px; }

.hdr-format-item strong {
    font-size: 14px;
    font-weight: 600;
}

.hdr-format-item span {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* ── Responsive ── */
@media (max-width: 768px) {
    hdr-explainer {
        grid-template-columns: 1fr;
    }

    .hdr-explainer-diagram {
        grid-auto-flow: column;
        min-width: unset;
    }

    .hdr-layer { min-width: 120px; }
}