/* ============================================================
   STAGE 4 — CASE STUDIES CSS
   Append to the bottom of public/css/style.css.
   All classes here are new — none duplicate Stages 1, 2, or 3.
   Classes reused from earlier stages: .inner-hero, .breadcrumb,
   .section-label, .section-header, .section-header__sub,
   .service-page-grid, .service-page-sidebar, .sidebar-cta-card,
   .sidebar-related, .sidebar-related__link, .cta-banner,
   .also-consider, .related-services, .related-services--3col,
   .related-service-card, .link-arrow, .metric-value, .metric-label,
   .capability-list, .capability-list--lg, .btn-primary, .btn-outline
   ============================================================ */

/* ------------------------------------------------------------
   FILTER BAR — case studies index page
   ------------------------------------------------------------ */
.cs-filter-bar {
    background: white;
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-md) 0;
    position: sticky;
    top: 68px; /* below the fixed site header */
    z-index: 90;
}

.cs-filter-bar__inner {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
    flex-wrap: wrap;
}

.cs-filter-bar__label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    white-space: nowrap;
}

.cs-filter-bar__pills {
    display: flex;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

.cs-pill {
    display: inline-block;
    padding: 0.375rem 1rem;
    border-radius: 100px;
    font-size: 0.8125rem;
    font-weight: 500;
    border: 1px solid var(--color-border);
    background: transparent;
    color: var(--color-text-muted);
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-body);
}

.cs-pill:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    background: white;
}

.cs-pill--active {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}

/* ------------------------------------------------------------
   CASE STUDY GRID — index page
   ------------------------------------------------------------ */
.cs-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-lg);
}

/* Base case study card */
.cs-card {
    background: white;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.cs-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--color-border);
    transition: var(--transition);
}

.cs-card:hover {
    border-color: var(--color-primary);
    box-shadow: 0 12px 40px rgba(0,0,74,0.09);
    transform: translateY(-3px);
}

.cs-card:hover::before {
    background: var(--color-accent);
}

/* Featured card spans full width */
.cs-card--featured {
    grid-column: 1 / -1;
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: var(--space-2xl);
    align-items: start;
}

.cs-card__meta {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

.cs-card__tag {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--color-accent-dark);
    background: rgba(219,180,94,0.1);
    border: 1px solid rgba(219,180,94,0.25);
    padding: 0.275rem 0.75rem;
    border-radius: 100px;
}

.cs-card__industry {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--color-text-muted);
}

.cs-card__title {
    font-size: 1.125rem;
    color: var(--color-primary);
    line-height: 1.4;
    margin: 0;
}

.cs-card--featured .cs-card__title {
    font-size: 1.375rem;
}

.cs-card__excerpt {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    line-height: 1.75;
    margin: 0;
    flex: 1;
}

/* Metrics row inside cards */
.cs-card__metrics {
    display: flex;
    gap: var(--space-xl);
    padding: var(--space-md) 0;
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    flex-wrap: wrap;
}

.cs-card__metric {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

/* Arrow link for non-featured cards */
.cs-card__link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-top: auto;
    transition: var(--transition);
}

.cs-card__link:hover {
    gap: 10px;
    color: var(--color-accent-dark);
}

/* Right visual panel on featured card */
.cs-card__visual {
    background: var(--color-bg-subtle);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: var(--space-lg);
    align-self: stretch;
}

.cs-card__stat-block {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.cs-stat {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    font-size: 0.875rem;
    color: var(--color-text-muted);
    font-weight: 500;
}

.cs-stat__icon {
    width: 36px;
    height: 36px;
    min-width: 36px;
    background: var(--color-primary);
    color: var(--color-accent);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
}

/* ------------------------------------------------------------
   CASE STUDY DETAIL — hero metrics strip
   ------------------------------------------------------------ */
.cs-detail-meta {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-md);
    flex-wrap: wrap;
}

.cs-detail-meta__industry {
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: rgba(255,255,255,0.55);
}

.cs-detail-hero-metrics {
    display: flex;
    gap: var(--space-xl);
    margin-top: var(--space-xl);
    padding-top: var(--space-xl);
    border-top: 1px solid rgba(255,255,255,0.12);
    flex-wrap: wrap;
}

.cs-detail-hero-metric {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

/* Reuses .metric-value and .metric-label from Stage 1 */
.cs-detail-hero-metric .metric-value {
    font-size: 2rem;
    color: var(--color-accent);
}

.cs-detail-hero-metric .metric-label {
    color: rgba(255,255,255,0.55);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-top: 0;
}

/* ------------------------------------------------------------
   CASE STUDY DETAIL — content sections
   ------------------------------------------------------------ */
.cs-section {
    padding: var(--space-xl) 0;
    border-bottom: 1px solid var(--color-border);
}

.cs-section:last-child {
    border-bottom: none;
}

.cs-section__label {
    display: flex;
    align-items: baseline;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
}

.cs-section__num {
    font-family: var(--font-display);
    font-size: 0.875rem;
    font-weight: 700;
    color: var(--color-accent);
    letter-spacing: 0.06em;
    flex-shrink: 0;
}

.cs-section__title {
    font-size: 1.25rem;
    color: var(--color-primary);
    margin: 0;
    line-height: 1.3;
}

.cs-section__body p {
    font-size: 1rem;
    color: var(--color-text-muted);
    line-height: 1.8;
    margin-bottom: var(--space-md);
}

.cs-section__body p:last-child { margin-bottom: 0; }

/* Results grid inside detail */
.cs-results-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-lg);
}

.cs-result {
    background: var(--color-bg-subtle);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    border-top: 3px solid var(--color-accent);
}

.cs-result__value {
    display: block;
    font-family: var(--font-display);
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1;
    margin-bottom: var(--space-sm);
}

.cs-result__title {
    font-size: 0.9375rem;
    color: var(--color-primary);
    margin-bottom: var(--space-sm);
    line-height: 1.3;
}

.cs-result p {
    font-size: 0.875rem;
    color: var(--color-text-muted);
    line-height: 1.65;
    margin: 0;
}

/* Testimonial block */
.cs-testimonial {
    background: var(--color-primary);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    margin: 0;
    position: relative;
}

.cs-testimonial::before {
    content: '\201C';
    position: absolute;
    top: var(--space-md);
    left: var(--space-xl);
    font-family: var(--font-display);
    font-size: 4rem;
    color: var(--color-accent);
    opacity: 0.4;
    line-height: 1;
}

.cs-testimonial__quote {
    font-size: 1.0625rem;
    color: rgba(255,255,255,0.9);
    line-height: 1.8;
    font-style: italic;
    padding-top: var(--space-md);
    margin-bottom: var(--space-lg);
}

.cs-testimonial__footer {
    display: flex;
    flex-direction: column;
    gap: 3px;
    padding-top: var(--space-md);
    border-top: 1px solid rgba(255,255,255,0.12);
}

.cs-testimonial__author {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--color-accent);
}

.cs-testimonial__org {
    font-size: 0.8125rem;
    color: rgba(255,255,255,0.5);
}

/* ------------------------------------------------------------
   CASE STUDY DETAIL — sidebar quick facts
   ------------------------------------------------------------ */
.cs-detail-quick-facts {
    background: var(--color-bg-subtle);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
}

.cs-detail-quick-facts h5 {
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--color-text-muted);
    margin-bottom: var(--space-md);
}

.cs-facts-list {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: var(--space-sm) var(--space-md);
    align-items: baseline;
    margin: 0;
}

.cs-facts-list dt {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-text-muted);
    white-space: nowrap;
}

.cs-facts-list dd {
    font-size: 0.875rem;
    color: var(--color-text);
    line-height: 1.5;
    margin: 0;
}

/* ------------------------------------------------------------
   RESPONSIVE — STAGE 4
   ------------------------------------------------------------ */
@media (max-width: 1024px) {
    .cs-card--featured          { grid-template-columns: 1fr; }
    .cs-card__visual            { display: none; }
    .cs-results-grid            { grid-template-columns: repeat(2, 1fr); }
    .cs-filter-bar              { top: 0; position: static; }
}

@media (max-width: 768px) {
    .cs-grid                    { grid-template-columns: 1fr; }
    .cs-card--featured          { grid-column: auto; }
    .cs-results-grid            { grid-template-columns: 1fr; }
    .cs-detail-hero-metrics     { gap: var(--space-lg); }
    .cs-facts-list              { grid-template-columns: 1fr; }
    .cs-facts-list dt           { margin-top: var(--space-sm); }
    .cs-facts-list dt:first-child { margin-top: 0; }
}

@media (max-width: 480px) {
    .cs-card__metrics           { gap: var(--space-md); }
    .cs-detail-hero-metrics     { flex-direction: column; gap: var(--space-md); }
}