/* ============================================================
   CASE STUDIES PAGE — Ribbon system
   ============================================================ */

/* ─── PAGE HEADER ─────────────────────────────────────────── */
.cs-header {
  padding: clamp(5rem, 9vw, 7rem) 0 clamp(2.5rem, 5vw, 4rem);
  border-bottom: 1px solid var(--line);
  position: relative;
  overflow: hidden;
}
.cs-header::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 85% 20%, var(--teal-glow), transparent 50%);
  pointer-events: none;
}
.cs-header-in {
  position: relative;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 4vw, 3rem);
  display: grid;
  grid-template-columns: 1.4fr auto;
  gap: 3rem;
  align-items: end;
}
.cs-header h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  margin-bottom: 1rem;
  max-width: 720px;
}
.cs-header .lede {
  font-size: clamp(1.0625rem, 1.5vw, 1.25rem);
  color: var(--muted);
  max-width: 540px;
  line-height: 1.55;
}

/* NDA + DSGVO badge box — top right of header */
.nda-note {
  font-size: 0.75rem;
  color: var(--muted);
  padding: 1rem 1.2rem;
  border-left: 2px solid var(--teal);
  background: var(--teal-tint);
  border-radius: 0 2px 2px 0;
  max-width: 280px;
  line-height: 1.55;
}
.nda-note strong {
  display: block;
  color: var(--ink);
  font-weight: 600;
  margin-bottom: 4px;
  font-size: 0.8125rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

/* ─── RIBBONS CONTAINER ───────────────────────────────────── */
.ribbons {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: clamp(2rem, 5vw, 4rem) clamp(1.25rem, 4vw, 3rem) clamp(4rem, 8vw, 6rem);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.ribbon {
  background: var(--bg);
  border: 1px solid var(--line-2);
  border-radius: 4px;
  overflow: hidden;
  transition: border-color var(--t-med), box-shadow var(--t-med);
}
.ribbon.open {
  border-color: var(--teal);
  box-shadow: 0 8px 32px var(--teal-glow);
}

/* ─── Closed header strip ─────────────────────────────────── */
.ribbon-head {
  display: grid;
  grid-template-columns: 70px 1fr auto 40px;
  gap: 1.5rem;
  align-items: center;
  padding: 1.4rem 1.6rem;
  cursor: pointer;
  user-select: none;
  background: var(--bg);
  transition: background var(--t-fast);
}
.ribbon-head:hover { background: var(--bg-2); }
.ribbon.open .ribbon-head { background: var(--bg-2); }

.ribbon-year {
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--teal);
  letter-spacing: -0.01em;
}
.ribbon-meta {
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.3rem;
}
.ribbon-title {
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--ink);
  letter-spacing: -0.01em;
  line-height: 1.25;
}
.ribbon-tags {
  display: flex;
  gap: 5px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

/* Project tags vs NDA badge — different shapes */
.r-tag {
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--teal);
  background: transparent;
  border: 1px solid var(--teal-tint);
  padding: 3px 10px;
  border-radius: 999px;
  white-space: nowrap;
}
.r-nda {
  border-radius: 2px;
  border-style: dashed;
  border-color: var(--muted-2);
  color: var(--muted);
  letter-spacing: 0.1em;
  font-size: 9.5px;
  text-transform: uppercase;
  font-weight: 600;
  padding: 3px 8px;
  background: transparent;
}

/* Plus/minus toggle */
.ribbon-toggle {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: 1px solid var(--line-2);
  background: transparent;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--t-med);
  flex-shrink: 0;
  position: relative;
}
.ribbon.open .ribbon-toggle {
  background: var(--teal);
  border-color: var(--teal);
}
.ribbon-toggle::before,
.ribbon-toggle::after {
  content: '';
  position: absolute;
  background: var(--ink);
  transition: all var(--t-med);
}
.ribbon-toggle::before { width: 11px; height: 1.5px; }
.ribbon-toggle::after  { width: 1.5px; height: 11px; }
.ribbon.open .ribbon-toggle::before,
.ribbon.open .ribbon-toggle::after { background: #fff; }
.ribbon.open .ribbon-toggle::after { opacity: 0; }

/* ─── Expanded body ──────────────────────────────────────── */
.ribbon-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--t-med);
}
.ribbon.open .ribbon-body { max-height: 1500px; }

.ribbon-content {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 2rem;
  padding: 0.5rem 1.6rem 1.6rem;
  align-items: start;
}

.ribbon-visual {
  background: var(--bg-3);
  border: 1px solid var(--line);
  border-radius: 3px;
  aspect-ratio: 4/3;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
}
.ribbon-visual img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.ribbon-visual .placeholder {
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--muted-2);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* ─── PSR Tabs ────────────────────────────────────────────── */
.psr {
  display: flex;
  flex-direction: column;
  min-height: 100%;
}
.psr-tabs {
  display: flex;
  border-bottom: 1px solid var(--line);
  margin-bottom: 1.25rem;
}
.psr-tab {
  font-family: var(--font-display);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  background: transparent;
  border: none;
  padding: 0.65rem 0;
  margin-right: 2rem;
  cursor: pointer;
  position: relative;
  transition: color var(--t-fast);
}
.psr-tab:hover { color: var(--ink); }
.psr-tab.active { color: var(--teal); }
.psr-tab.active::after {
  content: '';
  position: absolute;
  left: 0; right: 0;
  bottom: -1px;
  height: 2px;
  background: var(--teal);
}

.psr-pane {
  display: none;
  animation: paneFade .25s ease both;
}
.psr-pane.active { display: block; }
@keyframes paneFade {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: translateY(0); }
}
.psr-pane p {
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--ink-2);
  margin-bottom: 0.75rem;
}
.psr-pane ul {
  list-style: none;
  margin-top: 0.5rem;
}
.psr-pane li {
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--ink-2);
  padding: 0.4rem 0 0.4rem 1.1rem;
  position: relative;
  border-bottom: 1px solid var(--line);
}
.psr-pane li:last-child { border-bottom: none; }
.psr-pane li::before {
  content: '';
  position: absolute;
  left: 0; top: 1.05rem;
  width: 7px; height: 1px;
  background: var(--teal);
}

/* ─── KPI strip at the bottom ─────────────────────────────── */
.ribbon-kpis {
  display: flex;
  gap: 2.5rem;
  padding: 1.25rem 1.6rem;
  border-top: 1px solid var(--line);
  background: var(--bg-2);
  flex-wrap: wrap;
}
.ribbon-kpi-num {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--teal);
  letter-spacing: -0.02em;
  line-height: 1;
}
.ribbon-kpi-label {
  font-size: 0.6875rem;
  color: var(--muted);
  margin-top: 4px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

/* ─── Mobile ──────────────────────────────────────────────── */
@media (max-width: 880px) {
  .cs-header-in {
    grid-template-columns: 1fr;
    align-items: start;
  }
  .nda-note { max-width: 100%; }

  .ribbon-head {
    grid-template-columns: 50px 1fr 36px;
    gap: 1rem;
    padding: 1.1rem 1.2rem;
  }
  .ribbon-tags { display: none; }
  .ribbon-content {
    grid-template-columns: 1fr;
    padding: 0.5rem 1.2rem 1.2rem;
    gap: 1.25rem;
  }
  .ribbon-visual { aspect-ratio: 16/10; }
  .ribbon-kpis {
    padding: 1rem 1.2rem;
    gap: 1.5rem;
  }
  .psr-tab { margin-right: 1.25rem; }
}
@media (max-width: 480px) {
  .ribbon-year { font-size: 0.9rem; }
  .ribbon-title { font-size: 0.95rem; }
}