/* =========================================================
   Agence Melo Design — Case Study pages v3
   Black x Orange · Editorial layout
   ========================================================= */

/* ---------- Back link ---------- */
.cs-back {
  position: fixed;
  top: calc(var(--nav-h) + 1rem);
  left: clamp(1.25rem, 3.5vw, 2.5rem);
  z-index: 200;
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  padding: 0.4rem 0.9rem;
  border: 1px solid var(--line);
  border-radius: 50px;
  background: rgba(5,5,5,0.82);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition: color 0.22s, border-color 0.22s;
}
.cs-back:hover { color: var(--ink); border-color: var(--accent); }
.cs-back svg { width: 14px; height: 14px; flex-shrink: 0; }

/* ---------- Hero ---------- */
.cs-hero {
  position: relative;
  height: 72vh;
  min-height: 520px;
  max-height: 780px;
  overflow: hidden;
  display: flex;
  align-items: flex-end;
}
.cs-hero__img {
  position: absolute;
  inset: 0;
  width: 100%; height: 100%;
  object-fit: cover;
  object-position: center top;
  transform: scale(1.04);
  transition: transform 6s ease;
}
.cs-hero:hover .cs-hero__img { transform: scale(1); }
.cs-hero__overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(5,5,5,0.9) 0%, rgba(5,5,5,0.3) 55%, transparent 100%);
}
.cs-hero__content {
  position: relative;
  z-index: 2;
  width: 100%;
  padding: var(--sp-6) clamp(1.25rem, 3.5vw, 2.5rem) var(--sp-5);
  max-width: var(--max-w);
  margin: 0 auto;
}
.cs-hero__eyebrow {
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent-2);
  margin-bottom: var(--sp-2);
}
.cs-hero__title {
  font-family: var(--f-display);
  font-size: clamp(2.4rem, 5vw + 0.5rem, 5rem);
  font-weight: 400;
  color: #fff;
  line-height: 1.05;
  margin-bottom: var(--sp-3);
  letter-spacing: -0.03em;
}
.cs-hero__title .italic { font-style: italic; font-weight: 300; }
.cs-hero__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}
.cs-hero__tag {
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.9);
  border: 1px solid rgba(255,255,255,0.3);
  padding: 0.25rem 0.8rem;
  border-radius: 50px;
  backdrop-filter: blur(4px);
}

/* ---------- Metrics bar ---------- */
.cs-metrics {
  background: var(--bg-3);
  border-bottom: 1px solid var(--line);
  padding: 0;
}
.cs-metrics__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 3.5vw, 2.5rem);
}
.cs-metric {
  text-align: center;
  padding: var(--sp-4) var(--sp-2);
  border-right: 1px solid var(--line);
  position: relative;
}
.cs-metric:last-child { border-right: none; }
.cs-metric__num {
  font-family: var(--f-display);
  font-size: clamp(2rem, 4vw, 3.2rem);
  font-weight: 400;
  font-style: italic;
  color: var(--accent);
  line-height: 1;
  display: block;
}
.cs-metric__label {
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 0.4rem;
  display: block;
}

/* ---------- Tab navigation ---------- */
.cs-tabs {
  background: var(--bg-2);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: var(--nav-h);
  z-index: 100;
}
.cs-tabs__nav {
  display: flex;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
  gap: 0;
}
.cs-tabs__nav::-webkit-scrollbar { display: none; }
.cs-tab-btn {
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  padding: var(--sp-3) var(--sp-4);
  transition: color 0.22s, border-color 0.22s;
  white-space: nowrap;
  line-height: 1;
  font-weight: 500;
}
.cs-tab-btn:hover { color: var(--ink); }
.cs-tab-btn.is-active {
  color: var(--ink);
  border-bottom-color: var(--accent);
}

/* ---------- Tab panels ---------- */
.cs-panel { display: none; }
.cs-panel.is-active { display: block; }

/* ---------- Main layout ---------- */
.cs-body {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: var(--sp-7) clamp(1.25rem, 3.5vw, 2.5rem);
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: var(--sp-6);
  align-items: start;
}
.cs-main { min-width: 0; }
.cs-sidebar {
  position: sticky;
  top: calc(var(--nav-h) + 2.5rem);
}

/* ---------- Section headings ---------- */
.cs-section { margin-bottom: var(--sp-6); }
.cs-section + .cs-section {
  padding-top: var(--sp-5);
  border-top: 1px solid var(--line);
}
.cs-section__label {
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: var(--sp-2);
  font-weight: 500;
}
.cs-section__title {
  font-family: var(--f-display);
  font-size: clamp(1.5rem, 2.5vw + 0.5rem, 2.4rem);
  font-weight: 400;
  margin-bottom: var(--sp-3);
  color: var(--ink);
  line-height: 1.15;
  letter-spacing: -0.02em;
}
.cs-section__body {
  font-size: var(--fs-lede);
  color: var(--ink-2);
  line-height: 1.8;
  max-width: 64ch;
}
.cs-section__body p + p { margin-top: var(--sp-3); }
.cs-section__body strong { color: var(--ink); font-weight: 600; }

/* ---------- Process steps ---------- */
.cs-steps {
  counter-reset: step;
  display: grid;
  gap: var(--sp-4);
  margin-top: var(--sp-4);
}
.cs-step {
  display: grid;
  grid-template-columns: 2.5rem 1fr;
  gap: var(--sp-3);
  align-items: start;
  padding: var(--sp-4);
  background: var(--bg-3);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  transition: border-color 0.25s, background 0.25s;
}
.cs-step:hover {
  border-color: var(--line-2);
  background: var(--bg-2);
}
.cs-step::before {
  counter-increment: step;
  content: "0" counter(step);
  font-family: var(--f-display);
  font-size: 1.2rem;
  color: var(--accent);
  font-style: italic;
  padding-top: 0.15rem;
}
.cs-step__title {
  font-family: var(--f-display);
  font-size: 1.1rem;
  font-weight: 400;
  margin-bottom: 0.5rem;
  color: var(--ink);
  letter-spacing: -0.01em;
}
.cs-step__desc {
  font-size: var(--fs-sm);
  color: var(--ink-2);
  line-height: 1.7;
}

/* ---------- Image blocks ---------- */
.cs-img-block {
  margin: var(--sp-5) 0;
  border-radius: var(--r-lg);
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--bg-3);
}
.cs-img-block img {
  width: 100%;
  display: block;
  object-fit: cover;
}
.cs-img-block__caption {
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  color: var(--muted);
  letter-spacing: 0.08em;
  padding: var(--sp-2) var(--sp-3);
  background: var(--bg-3);
  border-top: 1px solid var(--line);
}
.cs-images {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-3);
  margin: var(--sp-4) 0;
}
.cs-images--full { grid-template-columns: 1fr; }
.cs-images img {
  width: 100%;
  border-radius: var(--r-lg);
  object-fit: cover;
  aspect-ratio: 16 / 10;
  background: var(--bg-3);
}

/* ---------- Quote ---------- */
.cs-quote {
  position: relative;
  padding: var(--sp-4) var(--sp-5);
  margin: var(--sp-5) 0;
  background: var(--bg-3);
  border-radius: var(--r-lg);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
}
.cs-quote::before {
  content: '"';
  position: absolute;
  top: var(--sp-2);
  left: var(--sp-3);
  font-family: var(--f-display);
  font-size: 4rem;
  color: var(--accent);
  line-height: 1;
  opacity: 0.3;
}
.cs-quote__text {
  font-family: var(--f-display);
  font-size: clamp(1.05rem, 1.5vw + 0.4rem, 1.3rem);
  font-style: italic;
  font-weight: 300;
  color: var(--ink);
  line-height: 1.6;
}
.cs-quote__author {
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-top: var(--sp-2);
  font-weight: 500;
}

/* ---------- Sidebar ---------- */
.cs-card {
  background: var(--bg-3);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  padding: var(--sp-3);
  margin-bottom: var(--sp-3);
}
.cs-card__title {
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: var(--sp-2);
  font-weight: 500;
}
.cs-card__list { display: grid; gap: var(--sp-2); }
.cs-card__item { display: flex; flex-direction: column; gap: 0.12rem; }
.cs-card__item-key {
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  color: var(--muted);
  letter-spacing: 0.08em;
}
.cs-card__item-val {
  font-family: var(--f-display);
  font-size: 0.95rem;
  color: var(--ink);
}

/* ---------- Tags ---------- */
.cs-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: var(--sp-2);
}
.cs-tag {
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  letter-spacing: 0.06em;
  color: var(--ink-2);
  background: var(--bg-2);
  border: 1px solid var(--line);
  padding: 0.28rem 0.7rem;
  border-radius: 50px;
  transition: border-color 0.2s, color 0.2s;
}
.cs-tag:hover { border-color: var(--accent); color: var(--accent); }

/* ---------- Next project ---------- */
.cs-next {
  background: var(--bg-3);
  border-top: 1px solid var(--line);
  padding: var(--sp-6) 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.cs-next::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--accent-glow) 0%, transparent 60%);
  pointer-events: none;
}
.cs-next__label {
  font-family: var(--f-sans);
  font-size: var(--fs-xs);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: var(--sp-2);
}
.cs-next__title {
  font-family: var(--f-display);
  font-size: clamp(1.5rem, 3vw, 2.8rem);
  font-weight: 400;
  color: var(--ink);
  margin-bottom: var(--sp-3);
  letter-spacing: -0.02em;
}

/* ---------- PDF viewer ---------- */
.cs-pdf { background: var(--bg-2); padding: var(--sp-6) 0; }
.cs-pdf__wrap {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 3.5vw, 2.5rem);
}
.cs-pdf__wrap p { color: var(--muted); font-size: var(--fs-sm); }
.cs-pdf__viewer iframe { display: block; width: 100%; height: 640px; border-radius: var(--r-lg); }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .cs-body { grid-template-columns: 1fr; }
  .cs-sidebar {
    position: static;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--sp-3);
  }
  .cs-metrics__grid { grid-template-columns: repeat(2, 1fr); }
  .cs-metric { border-right: none; border-bottom: 1px solid var(--line); }
  .cs-metric:nth-child(2n) { border-right: 1px solid var(--line); }
  .cs-metric:nth-child(3),
  .cs-metric:last-child { border-bottom: none; }
}
@media (max-width: 600px) {
  .cs-hero { height: 60vh; min-height: 400px; }
  .cs-images { grid-template-columns: 1fr; }
  .cs-sidebar { grid-template-columns: 1fr; }
  .cs-metrics__grid { grid-template-columns: 1fr 1fr; }
  .cs-back { font-size: 0; padding: 0.6rem; border-radius: 50%; }
  .cs-back svg { width: 16px; height: 16px; }
  .cs-pdf__viewer iframe { height: 420px; }
}