:root {
    --max-w:        1200px;
    --gutter:       clamp(20px, 5vw, 60px);
    --accent:       #6846c6;
    --accent-dark:  #4f34a3;
    --accent-light: #ede8fb;
    --ink:          #0e0e12;
    --ink-3:        #555564;
    --white:        #ffffff;
    --border:       rgba(0,0,0,.08);
    --font-sans:    'Inter', sans-serif;
    --ease:         cubic-bezier(.22,1,.36,1);
}

/* ── shared ── */
.bd-container { max-width: var(--max-w); margin: 0 auto; padding: 0 var(--gutter); }

.bd-label {
    display: inline-block;
    color: var(--accent);
    font-size: .8rem;
    font-weight: 700;
    letter-spacing: .18em;
    text-transform: uppercase;
    margin-bottom: 16px;
}

.bd-title {
    font-size: clamp(2rem, 4vw, 3rem);
    line-height: 1.15;
    color: var(--ink);
    font-weight: 700;
}

/* ── scroll reveal ── */
.bd-reveal {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity .65s var(--ease), transform .65s var(--ease);
}
.bd-reveal.visible { opacity: 1; transform: none; }
.bd-reveal[data-delay="1"] { transition-delay: .1s; }
.bd-reveal[data-delay="2"] { transition-delay: .2s; }
.bd-reveal[data-delay="3"] { transition-delay: .3s; }
.bd-reveal[data-delay="4"] { transition-delay: .4s; }
.bd-reveal[data-delay="5"] { transition-delay: .5s; }

/* ═══════════════════════════════════════
    INTRO
═══════════════════════════════════════ */
.bd-intro {
    padding: 100px var(--gutter) 72px;
    position: relative;
    overflow: hidden;
    max-width: var(--max-w);
    width: 100%;
    margin: 0 auto;
}

.bd-intro-inner { max-width: 760px; }
.bd-intro-inner .bd-title { margin-bottom: 20px; }
.bd-intro-inner p {
    font-size: 1.0625rem;
    color: var(--ink-3);
    line-height: 1.85;
    max-width: 620px;
}

/* ═══════════════════════════════════════
    SECTION HEADERS (reused)
═══════════════════════════════════════ */
.bd-section-header {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: end;
    margin-bottom: 48px;
}
.bd-section-header-right {
    color: var(--ink-3);
    font-size: .975rem;
    line-height: 1.85;
    padding-bottom: 4px;
}

/* ═══════════════════════════════════════
    CORE DISCIPLINES — flip grid
═══════════════════════════════════════ */
.bd-disciplines-section { padding: 0 var(--gutter) 120px; }

.bd-solutions-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.bd-flip-wrap {
    height: 420px;
    perspective: 1000px;
    isolation: isolate;
}

.bd-flip-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
    transform-origin: center center;
    transition: transform .72s cubic-bezier(.4, 0, .2, 1);
    border-radius: 16px;
}

.bd-flip-wrap:hover .bd-flip-inner,
.bd-flip-wrap.flipped .bd-flip-inner {
    transform: rotateY(-180deg);
}

.bd-flip-front,
.bd-flip-back {
    position: absolute;
    inset: 0;
    border-radius: 16px;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    overflow: hidden;
}

.bd-flip-front {
    background: #fff;
    border: 1px solid var(--border);
    display: flex;
    flex-direction: column;
}

.bd-front-img {
    width: 100%;
    height: 240px;
    object-fit: cover;
    flex-shrink: 0;
    filter: brightness(.9) saturate(.88);
}

.bd-flip-front-body {
    padding: 24px 26px 22px;
    display: flex;
    flex-direction: column;
    flex: 1;
    border-top: 1px solid var(--border);
}

.bd-front-tag {
    font-size: .72rem;
    font-weight: 700;
    letter-spacing: .14em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 8px;
}

.bd-front-name {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--ink);
    line-height: 1.3;
}

.bd-front-hint {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    font-size: .76rem;
    font-weight: 600;
    color: rgba(104,70,198,.4);
    margin-top: auto;
    letter-spacing: .04em;
}
.bd-front-hint .material-icons-round { font-size: 14px; }

.bd-flip-back {
    transform: rotateY(180deg);
    background: var(--ink);
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
}

.bd-back-img {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    filter: brightness(.32) saturate(.65);
}

.bd-flip-back::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse 80% 60% at 20% 110%, rgba(104,70,198,.55) 0%, transparent 65%);
    pointer-events: none;
    z-index: 1;
}

.bd-back-content {
    position: relative;
    z-index: 2;
    padding: 32px 28px 28px;
}

.bd-back-tag {
    display: inline-block;
    font-size: .7rem;
    font-weight: 700;
    letter-spacing: .16em;
    text-transform: uppercase;
    color: rgba(255,255,255,.45);
    margin-bottom: 10px;
}

.bd-back-name {
    font-size: 1.2rem;
    font-weight: 700;
    color: #fff;
    line-height: 1.3;
    margin-bottom: 14px;
}

.bd-back-desc {
    font-size: .875rem;
    color: rgba(255,255,255,.65);
    line-height: 1.8;
    margin-bottom: 26px;
}

.bd-back-link {
    display: inline-flex;
    align-items: center;
    gap: 9px;
    padding: 11px 20px;
    background: var(--accent);
    color: #fff;
    border-radius: 8px;
    font-weight: 600;
    font-size: .875rem;
    transition: background .25s var(--ease), gap .25s var(--ease);
    width: fit-content;
}
.bd-back-link:hover { background: var(--accent-dark); gap: 14px; }
.bd-back-link .material-icons-round { font-size: 16px; }

/* ═══════════════════════════════════════
    INFRASTRUCTURE & RESILIENCE — horizontal list
═══════════════════════════════════════ */
.bd-infra-section {
    padding: 0 var(--gutter) 120px;
}

.bd-infra-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2px;
    border-radius: 16px;
    overflow: hidden;
    border: 1px solid var(--border);
}

.bd-infra-item {
    background: #fff;
    padding: 40px 36px;
    border-right: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    position: relative;
    transition: background .3s var(--ease);
    display: flex;
    gap: 24px;
    align-items: flex-start;
}
.bd-infra-item:hover { background: #faf9ff; }
.bd-infra-item:nth-child(2n) { border-right: none; }
.bd-infra-item:nth-child(3),
.bd-infra-item:nth-child(4) { border-bottom: none; }

.bd-infra-item::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: var(--accent);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform .35s var(--ease);
}
.bd-infra-item:hover::before { transform: scaleX(1); }

.bd-infra-icon {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    background: var(--accent-light);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: background .3s var(--ease);
}
.bd-infra-item:hover .bd-infra-icon { background: var(--accent); }
.bd-infra-icon .material-icons-round {
    font-size: 22px;
    color: var(--accent);
    transition: color .3s var(--ease);
}
.bd-infra-item:hover .bd-infra-icon .material-icons-round { color: #fff; }

.bd-infra-body {}
.bd-infra-name {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--ink);
    margin-bottom: 10px;
    line-height: 1.3;
}
.bd-infra-desc {
    font-size: .875rem;
    color: var(--ink-3);
    line-height: 1.75;
}

/* ═══════════════════════════════════════
    APPROACH STRIP
═══════════════════════════════════════ */
.bd-approach-section {
    padding: 100px var(--gutter);
    background: #f8f9fb;
    position: relative;
    overflow: hidden;
}
.bd-approach-section::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse 50% 70% at 100% 0%, rgba(104,70,198,.05) 0%, transparent 60%);
    pointer-events: none;
}

.bd-approach-header {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: end;
    margin-bottom: 64px;
}
.bd-approach-header-right {
    color: var(--ink-3);
    font-size: .975rem;
    line-height: 1.85;
    padding-bottom: 4px;
}

.bd-approach-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2px;
    border-radius: 16px;
    overflow: hidden;
    border: 1px solid var(--border);
}

.bd-approach-item {
    background: #fff;
    padding: 36px 28px 32px;
    border-right: 1px solid var(--border);
    position: relative;
    transition: background .3s var(--ease);
}
.bd-approach-item:last-child { border-right: none; }
.bd-approach-item:hover { background: #faf9ff; }

.bd-approach-item::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: var(--accent);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform .35s var(--ease);
}
.bd-approach-item:hover::before { transform: scaleX(1); }

.bd-approach-num {
    font-size: 2.4rem;
    font-weight: 800;
    color: var(--accent-light);
    line-height: 1;
    margin-bottom: 16px;
    letter-spacing: -.02em;
}
.bd-approach-item:hover .bd-approach-num { color: rgba(104,70,198,.2); }

.bd-approach-name {
    font-size: 1rem;
    font-weight: 700;
    color: var(--ink);
    margin-bottom: 10px;
    line-height: 1.3;
}

.bd-approach-desc {
    font-size: .875rem;
    color: var(--ink-3);
    line-height: 1.75;
}

/* ═══════════════════════════════════════
    CTA
═══════════════════════════════════════ */
.bd-cta-strip { padding: 100px var(--gutter); }
.bd-cta-inner {
    max-width: var(--max-w);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 60px;
    padding: 64px;
    border-radius: 24px;
    background: var(--ink);
    position: relative;
    overflow: hidden;
}
.bd-cta-inner::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
    radial-gradient(ellipse 50% 100% at 10% 50%, rgba(104,70,198,.35) 0%, transparent 60%),
    radial-gradient(ellipse 40% 80% at 90% 20%, rgba(37,99,235,.2) 0%, transparent 60%);
    pointer-events: none;
}
.bd-cta-text { flex: 1; position: relative; }
.bd-cta-text .bd-label { color: rgba(255,255,255,.55); }
.bd-cta-text h2 {
    font-size: clamp(1.6rem, 3vw, 2.2rem);
    color: #fff;
    line-height: 1.2;
    margin-bottom: 12px;
}
.bd-cta-text p {
    font-size: .95rem;
    color: rgba(255,255,255,.5);
    line-height: 1.8;
    max-width: 480px;
}
.bd-cta-actions {
    display: flex;
    flex-direction: column;
    gap: 12px;
    flex-shrink: 0;
    position: relative;
}
.bd-btn-primary-sol {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 26px;
    background: var(--accent);
    color: #fff;
    border-radius: 8px;
    font-weight: 600;
    font-size: .95rem;
    white-space: nowrap;
    transition: background .25s var(--ease), transform .25s var(--ease), box-shadow .25s var(--ease);
}
.bd-btn-primary-sol:hover {
    background: var(--accent-dark);
    transform: translateY(-2px);
    box-shadow: 0 10px 28px rgba(104,70,198,.35);
}
.bd-btn-primary-sol .material-icons-round { font-size: 18px; }
.bd-btn-secondary-sol {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 26px;
    background: transparent;
    color: rgba(255,255,255,.8);
    border: 1.5px solid rgba(255,255,255,.2);
    border-radius: 8px;
    font-weight: 600;
    font-size: .95rem;
    white-space: nowrap;
    transition: background .25s var(--ease), border-color .25s var(--ease);
}
.bd-btn-secondary-sol:hover {
    background: rgba(255,255,255,.06);
    border-color: rgba(255,255,255,.4);
}

/* ═══════════════════════════════════════
    RESPONSIVE
═══════════════════════════════════════ */
@media (max-width: 1024px) {
    .bd-solutions-grid      { grid-template-columns: repeat(2, 1fr); }
    .bd-approach-grid       { grid-template-columns: repeat(2, 1fr); }
    .bd-approach-item       { border-right: none; border-bottom: 1px solid var(--border); }
    .bd-approach-item:last-child,
    .bd-approach-item:nth-child(3) { border-bottom: none; }
    .bd-section-header,
    .bd-approach-header     { grid-template-columns: 1fr; gap: 16px; }
}
@media (max-width: 768px) {
    .bd-intro               { padding: 72px var(--gutter) 48px; }
    .bd-disciplines-section { padding: 0 var(--gutter) 80px; }
    .bd-infra-section       { padding: 0 var(--gutter) 80px; }
    .bd-solutions-grid      { grid-template-columns: 1fr; }
    .bd-flip-wrap           { height: 400px; }
    .bd-infra-grid          { grid-template-columns: 1fr; border-radius: 12px; }
    .bd-infra-item          { border-right: none; border-bottom: 1px solid var(--border); }
    .bd-infra-item:nth-child(4) { border-bottom: none; }
    .bd-approach-section    { padding: 72px var(--gutter); }
    .bd-approach-grid       { grid-template-columns: 1fr; border-radius: 12px; }
    .bd-approach-item       { border-bottom: 1px solid var(--border); border-right: none; }
    .bd-approach-item:last-child { border-bottom: none; }
    .bd-cta-strip           { padding: 0 var(--gutter) 80px; }
    .bd-cta-inner {
    flex-direction: column;
    align-items: flex-start;
    padding: 48px 32px;
    gap: 32px;
    }
    .bd-cta-actions         { width: 100%; }
    .bd-btn-primary-sol,
    .bd-btn-secondary-sol   { width: 100%; justify-content: center; }
}