/* ─────────────────────────────────────────
   Case study pages (extends style.css)
───────────────────────────────────────── */

.cs-hero {
  padding: 10rem 0 var(--space-lg);
}

.cs-back {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
  transition: color var(--dur-fast);
}

.cs-back:hover {
  color: var(--color-text);
}

.cs-title {
  font-size: var(--text-section);
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1;
  color: var(--color-text);
}

.cs-tagline {
  font-size: clamp(1.2rem, 2vw, 1.6rem);
  font-weight: 400;
  line-height: 1.4;
  color: var(--color-text-muted);
  max-width: 44ch;
  margin-top: 1.25rem;
}

.cs-meta {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem 2rem;
  margin-top: var(--space-lg);
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-border);
}

.cs-meta dt {
  font-size: var(--text-label);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.cs-meta dd {
  font-size: 0.95rem;
  line-height: 1.5;
  color: var(--color-text);
}

.cs-meta dd a {
  border-bottom: 1px solid var(--color-border);
  transition: border-color var(--dur-fast);
}

.cs-meta dd a:hover {
  border-color: var(--color-text);
}

.cs-cover {
  margin-top: var(--space-lg);
  border-radius: 4px;
  overflow: hidden;
  background: var(--color-surface);
  aspect-ratio: 1350 / 1080;
}

.cs-cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* Numbers strip */
.cs-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  padding: var(--space-lg) 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.cs-stat strong {
  display: block;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.1;
  color: var(--color-text);
}

.cs-stat span {
  display: block;
  font-size: 0.85rem;
  line-height: 1.5;
  color: var(--color-text-muted);
  margin-top: 0.5rem;
  max-width: 22ch;
}

/* Sections */
.cs-section {
  padding: var(--space-xl) 0 0;
}

.cs-section:has(+ .cs-next) {
  padding-bottom: var(--space-xl);
}

.cs-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 2fr);
  gap: clamp(2rem, 6vw, 7rem);
  align-items: start;
}

.cs-aside {
  position: sticky;
  top: 8rem;
}

.cs-heading {
  font-size: clamp(1.6rem, 2.6vw, 2.3rem);
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--color-text);
  margin-top: 0.25rem;
}

.cs-body p {
  font-size: var(--text-body);
  line-height: 1.8;
  color: var(--color-text-muted);
  max-width: 62ch;
}

.cs-body p + p {
  margin-top: 1.25rem;
}

.cs-body p.cs-lead {
  color: var(--color-text);
}

.cs-body strong {
  font-weight: 600;
  color: var(--color-text);
}

.cs-body ul {
  margin-top: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.cs-body li {
  position: relative;
  padding-left: 1.5rem;
  font-size: var(--text-body);
  line-height: 1.7;
  color: var(--color-text-muted);
  max-width: 62ch;
}

.cs-body li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.8em;
  width: 0.5rem;
  height: 1px;
  background: var(--color-text-muted);
}

/* Figures */
.cs-figure {
  margin-top: var(--space-lg);
}

.cs-figure .cs-frame {
  border-radius: 4px;
  overflow: hidden;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
}

.cs-figure img {
  width: 100%;
}

.cs-figure figcaption {
  font-size: 0.82rem;
  line-height: 1.5;
  color: var(--color-text-muted);
  margin-top: 0.9rem;
}

.cs-figure-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

/* Phone gallery */
.cs-phones {
  display: flex;
  gap: 1.25rem;
  overflow-x: auto;
  padding-bottom: 1rem;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
}

.cs-phones::-webkit-scrollbar {
  height: 6px;
}

.cs-phones::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 3px;
}

.cs-phones figure {
  flex: 0 0 auto;
  width: clamp(220px, 24vw, 300px);
  scroll-snap-align: start;
}

.cs-phones .cs-frame {
  border-radius: 4px;
  overflow: hidden;
  background: var(--color-surface);
  aspect-ratio: 1290 / 2796;
}

.cs-phones img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.cs-phones figcaption {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  margin-top: 0.75rem;
  line-height: 1.5;
}

/* Decisions */
.cs-decisions {
  display: flex;
  flex-direction: column;
  counter-reset: decision;
}

.cs-decision {
  counter-increment: decision;
  display: grid;
  grid-template-columns: 3rem 1fr;
  gap: 1rem;
  padding: 2rem 0;
  border-top: 1px solid var(--color-border);
}

.cs-decision:last-child {
  border-bottom: 1px solid var(--color-border);
}

.cs-decision::before {
  content: counter(decision, decimal-leading-zero);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-muted);
  padding-top: 0.3rem;
}

.cs-decision h3 {
  font-size: 1.15rem;
  font-weight: 500;
  line-height: 1.35;
  color: var(--color-text);
  margin-bottom: 0.6rem;
}

.cs-decision p {
  font-size: 0.95rem;
  line-height: 1.75;
  color: var(--color-text-muted);
  max-width: 62ch;
}

.cs-decision p + p {
  margin-top: 0.75rem;
}

/* Tier table */
.cs-tiers {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-top: var(--space-md);
}

.cs-tier {
  border: 1px solid var(--color-border);
  border-radius: 20px;
  padding: 1.5rem;
}

.cs-tier h4 {
  font-size: 0.8rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-text-muted);
}

.cs-tier .cs-price {
  font-size: 1.5rem;
  font-weight: 500;
  color: var(--color-text);
  margin: 0.5rem 0 1rem;
}

.cs-tier ul {
  margin-top: 0;
  gap: 0.4rem;
}

.cs-tier li {
  font-size: 0.85rem;
  line-height: 1.5;
}

/* Next project */
.cs-next {
  padding: var(--space-xl) 0;
  border-top: 1px solid var(--color-border);
  text-align: center;
}

.cs-next-link {
  display: inline-block;
  font-size: var(--text-contact);
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1.1;
  color: var(--color-text);
  margin-top: var(--space-md);
}

.cs-next-link .arrow-up-right {
  transition: transform var(--dur-med) var(--ease-expo);
}

.cs-next-link:hover .arrow-up-right {
  transform: translate(4px, -4px);
}

/* Responsive */
@media (max-width: 1024px) {
  .cs-grid {
    grid-template-columns: 1fr;
    gap: var(--space-md);
  }

  .cs-aside {
    position: static;
  }

  .cs-meta,
  .cs-stats {
    grid-template-columns: repeat(2, 1fr);
  }

  .cs-tiers {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .cs-hero {
    padding-top: 7rem;
  }

  .cs-figure-pair {
    grid-template-columns: 1fr;
  }

  .cs-cover,
  .cs-figure .cs-frame {
    border-radius: 4px;
  }
}