/* ── Walkthrough Section (grey box) ─────────────── */
.walkthrough-section {
    background-color: var(--warm-grey);
    padding: 64px 72px;
    max-width: 1300px;
    margin: 0 auto 32px auto;
    border-radius: 24px;
}
.walkthrough-header { margin-bottom: 48px; }
.walkthrough-steps {
    display: flex;
    flex-direction: column;
    gap: 0;
}
.walkthrough-step {
    padding: 24px 0;
    border-bottom: 1px solid rgba(0,0,0,0.08);
    display: grid;
    grid-template-columns: 48px 1fr;
    gap: 32px;
    align-items: start;
}
.walkthrough-step:first-child { border-top: 1px solid rgba(0,0,0,0.08); }
.wt-number {
    font-size: 14px;
    font-weight: 600;
    color: var(--light-gray);
    padding-top: 4px;
}
.wt-trigger {
    display: flex;
    align-items: center;
    justify-content: space-between;
    cursor: pointer;
    -webkit-user-select: none;
    user-select: none;
}
.wt-trigger:hover .wt-chevron { opacity: 1; }
.wt-content h3 {
    font-size: 22px;
    font-weight: 600;
    letter-spacing: -0.02em;
    margin-bottom: 0;
    line-height: 1.3;
}
.wt-chevron {
    flex-shrink: 0;
    width: 16px;
    height: 16px;
    color: var(--light-gray);
    opacity: 0.6;
    transition: transform 0.3s ease, opacity 0.2s ease;
    margin-left: 16px;
}
.walkthrough-step.open .wt-chevron {
    transform: rotate(180deg);
    opacity: 1;
}
.wt-detail {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows 0.4s ease;
}
.walkthrough-step.open .wt-detail {
    grid-template-rows: 1fr;
}
.wt-detail-inner {
    overflow: hidden;
}
.wt-detail-inner > :first-child {
    margin-top: 16px;
}
.wt-content p {
    font-size: 17px;
    line-height: 1.7;
    color: #4a4a4a;
    max-width: 680px;
    margin-bottom: 16px;
}
.code-hint {
    display: inline-block;
    font-family: "SF Mono", "Fira Code", Monaco, Consolas, monospace;
    font-size: 13px;
    font-weight: 500;
    color: var(--gray);
    background: rgba(0,0,0,0.05);
    padding: 4px 12px;
    border-radius: 4px;
    margin-bottom: 16px;
}
.code-example {
    font-family: "SF Mono", "Fira Code", Monaco, Consolas, monospace;
    font-size: 13px;
    line-height: 1.6;
    color: #4a4a4a;
    background: rgba(0,0,0,0.04);
    padding: 16px 20px;
    border-radius: 8px;
    max-width: 520px;
}
.code-example .ce-comment { color: var(--light-gray); }
.code-example .ce-key { color: #4a4a4a; }
.code-example .ce-val { color: var(--black); font-weight: 500; }

/* ── Verified Delta Section (grey box, two-column) ── */
.delta-section {
    background-color: var(--warm-grey);
    padding: 64px 72px;
    max-width: 1300px;
    margin: 0 auto 32px auto;
    border-radius: 24px;
}
.delta-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: start;
}
.delta-headline {
    font-size: clamp(28px, 3.5vw, 40px);
    font-weight: 600;
    letter-spacing: -0.03em;
    line-height: 1.2;
    margin-bottom: 20px;
}
.delta-body {
    font-size: 17px;
    line-height: 1.7;
    color: #4a4a4a;
    margin-bottom: 16px;
}
.delta-body strong { color: var(--black); font-weight: 600; }
.properties-list {
    display: flex;
    flex-direction: column;
    gap: 0;
}
.property-item {
    padding: 20px 0;
    border-bottom: 1px solid rgba(0,0,0,0.08);
}
.property-item:first-child { border-top: 1px solid rgba(0,0,0,0.08); }
.property-item h4 {
    font-size: 17px;
    font-weight: 600;
    margin-bottom: 6px;
}
.property-item p {
    font-size: 15px;
    line-height: 1.6;
    color: #4a4a4a;
}

/* ── Boundary Embed (inside delta-section) ──────── */
.boundary-embed {
    margin-top: 56px;
    padding-top: 48px;
    border-top: 1px solid rgba(0,0,0,0.08);
}
.boundary-embed-header { margin-bottom: 32px; }
.boundary-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}
.boundary-col {
    background: var(--white);
    border: 1px solid rgba(0,0,0,0.08);
    border-radius: 16px;
    overflow: hidden;
}
.boundary-col.ledger-col {
    background: var(--black);
    color: var(--white);
    border-color: transparent;
}
.boundary-col-header {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 20px 24px;
    border-bottom: 1px solid rgba(0,0,0,0.06);
    font-size: 14px;
    font-weight: 600;
    letter-spacing: -0.01em;
}
.boundary-col-header svg { width: 18px; height: 18px; flex-shrink: 0; }
.boundary-col.ledger-col .boundary-col-header {
    border-bottom-color: rgba(255,255,255,0.1);
}
.boundary-row {
    display: flex;
    justify-content: space-between;
    padding: 12px 24px;
    border-bottom: 1px solid rgba(0,0,0,0.04);
    font-size: 14px;
}
.boundary-col.ledger-col .boundary-row {
    border-bottom-color: rgba(255,255,255,0.06);
}
.boundary-row:last-child { border-bottom: none; }
.boundary-row .b-key { color: var(--gray); }
.boundary-col.ledger-col .boundary-row .b-key { color: rgba(255,255,255,0.5); }
.boundary-row .b-val {
    font-family: "SF Mono", Monaco, monospace;
    font-size: 12px;
    font-weight: 600;
}
.boundary-col.ledger-col .boundary-row .b-val { color: #6ee7b7; }
.boundary-note {
    text-align: center;
    margin-top: 24px;
    font-size: 14px;
    color: var(--gray);
    line-height: 1.6;
    max-width: 640px;
    margin-left: auto;
    margin-right: auto;
}

/* ── Page-specific Mobile Overrides ────────────── */
@media (max-width: 1024px) {
    .walkthrough-section { padding: 40px 24px; margin: 0 12px 12px 12px; }
    .walkthrough-header { margin-bottom: 32px; }
    .section-headline { font-size: 28px; }
    .walkthrough-step {
        grid-template-columns: 32px 1fr;
        gap: 16px; padding: 20px 0;
    }
    .wt-content h3 { font-size: 19px; }
    .wt-content p { font-size: 16px; }
    .wt-chevron { margin-left: 12px; }
    .code-example { font-size: 12px; padding: 12px 16px; }

    .delta-section { padding: 40px 24px; margin: 0 12px 12px 12px; }
    .delta-grid { grid-template-columns: 1fr; gap: 40px; }
    .delta-headline { font-size: 28px; }

    .boundary-embed { margin-top: 40px; padding-top: 32px; }
    .boundary-grid { grid-template-columns: 1fr; gap: 16px; }
}