/* ────────────────────────────────────────────────────────────────────
   Use cases section ,  horizontal carousel with persona cards
   ──────────────────────────────────────────────────────────────────── */
.usecases {
  background: var(--paper);
  padding: 64px 0 80px;
  border-top: 1px solid var(--border2);
  font-family: system-ui;
  overflow: hidden;
}

.usecases-intro {
  max-width: 1280px;
  margin: 0 auto 32px;
  padding: 0 32px;
}
.usecases-eyebrow {
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--violet);
  margin: 0 0 10px;
}
.usecases-title {
  font-family: Georgia, serif;
  font-size: clamp(28px, 3vw, 40px);
  font-weight: 400;
  line-height: 1.08;
  letter-spacing: -0.025em;
  color: var(--ink);
  margin: 0;
  max-width: 620px;
}

/* ── Carousel ── */
.usecases-track-wrap {
  position: relative;
  overflow: hidden;
}
.usecases-track {
  display: flex;
  gap: 18px;
  padding: 0 32px;
  transition: transform 700ms cubic-bezier(0.22, 1, 0.36, 1);
  will-change: transform;
}

.usecase-card {
  flex: 0 0 72%;
  max-width: 980px;
  scroll-snap-align: start;
}
@media (max-width: 1280px) { .usecase-card { flex-basis: 78%; } }
@media (max-width: 720px)  { .usecase-card { flex-basis: 88%; } }

/* ── Card image / visual block ── */
.usecase-visual {
  position: relative;
  width: 100%;
  aspect-ratio: 21 / 9;
  border-radius: 12px;
  overflow: hidden;
  background: linear-gradient(180deg, #f7f4ed 0%, #f3efe7 100%);
  padding: 32px 44px;
  font-family: system-ui;
}
.usecase-visual--students {
  background: linear-gradient(180deg, #f7f4ed 0%, #f3efe7 100%);
}
.usecase-visual--teams {
  background: linear-gradient(180deg, #f7f4ed 0%, #f3efe7 100%);
}
.usecase-visual::before { content: none; }

/* Big persona word, top-left, with a soft blinking caret next to it. */
.usecase-visual h3 {
  position: relative;
  z-index: 2;
  font-family: Georgia, serif;
  font-weight: 400;
  font-style: normal;
  font-size: clamp(36px, 4vw, 56px);
  line-height: 1.0;
  letter-spacing: -0.02em;
  color: var(--ink);
  margin: 0;
  padding: 0;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.usecase-visual h3::after {
  content: '';
  display: inline-block;
  width: 4px;
  height: 0.78em;
  background: var(--violet);
  margin-left: 6px;
  animation: usecase-caret 1.05s steps(2) infinite;
  transform: translateY(0.08em);
}
@keyframes usecase-caret { 50% { opacity: 0; } }

/* ── In-card mock: document with one highlighted line + Cite button ── */
.usecase-mock {
  position: absolute;
  left: 9%;
  bottom: 0;
  width: 46%;
  max-width: 460px;
  aspect-ratio: 4 / 3.5;
  background: var(--paper);
  border-top-left-radius: 8px;
  border-top-right-radius: 8px;
  padding: 26px 26px 18px;
  box-shadow: 0 18px 50px rgba(15,14,17,0.10);
  display: flex;
  flex-direction: column;
  gap: 9px;
  overflow: hidden;
}
.usecase-mock .line {
  height: 8px;
  border-radius: 2px;
  background: rgba(15,14,17,0.10);
}
.usecase-mock .line.short { width: 60%; }
.usecase-mock .line.med { width: 84%; }
.usecase-mock .line.long { width: 96%; }
.usecase-mock .line.hl {
  /* Selected sentence ,  violet to signal the active claim that gets a citation */
  background: rgba(91,79,207,0.55);
  width: 72%;
}
.usecase-mock .gap { height: 6px; }
.usecase-mock .cite-btn {
  position: absolute;
  right: 22px;
  bottom: 22px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--violet);
  color: #fff;
  font-family: system-ui;
  font-size: 13.5px;
  font-weight: 500;
  padding: 8px 14px;
  border-radius: 999px;
}
.usecase-mock .cite-btn::before {
  content: '+';
  font-size: 16px;
  font-weight: 400;
  line-height: 1;
}

/* ── Floating verified-citation card on the right side ── */
.usecase-quote {
  position: absolute;
  right: 6%;
  top: 42%;
  width: 38%;
  max-width: 360px;
  background: var(--paper);
  border-radius: 10px;
  box-shadow:
    0 24px 60px rgba(15,14,17,0.14),
    0 2px 8px rgba(15,14,17,0.06);
  padding: 18px 20px;
  font-family: system-ui;
  transform: rotate(-1.5deg);
}
.usecase-quote p {
  margin: 0 0 10px;
  font-family: Georgia, serif;
  font-style: italic;
  font-size: 16px;
  line-height: 1.35;
  color: var(--ink);
}
.usecase-quote .verified {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--ink2);
}
.usecase-quote .verified .ok {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 12px; height: 12px;
  color: var(--violet);
}
.usecase-quote .verified .label {
  color: var(--violet);
  font-weight: 500;
}
.usecase-quote .verified .src { color: var(--ink3); margin-left: 2px; }

/* ── Variant: Researchers ,  Daily briefing list ── */
.usecase-mock--briefing {
  padding: 18px 18px 14px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.usecase-mock--briefing .briefing-head {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 11px;
  color: var(--ink3);
  margin-bottom: 4px;
}
.usecase-mock--briefing .briefing-head .dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--violet);
}
.usecase-mock--briefing .briefing-head .ct {
  margin-left: auto;
  background: var(--violet-light);
  color: var(--violet);
  font-size: 10px;
  font-weight: 600;
  padding: 1px 7px;
  border-radius: 999px;
}
.usecase-mock--briefing .b-card {
  border: 1px solid rgba(15,14,17,0.08);
  border-radius: 6px;
  padding: 8px 10px;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 8px;
  align-items: start;
  background: var(--paper);
}
.usecase-mock--briefing .b-card.active {
  border-color: rgba(91,79,207,0.30);
  background: rgba(237,233,255,0.45);
}
.usecase-mock--briefing .rel {
  width: 18px; height: 18px;
  border-radius: 3px;
  font-size: 9px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}
.usecase-mock--briefing .rel.h { background: #e0f5ee; color: #1a9e75; }
.usecase-mock--briefing .rel.m { background: #fdf3e3; color: #b97318; }
.usecase-mock--briefing .b-card .ttl {
  font-size: 10.5px;
  font-weight: 500;
  color: var(--ink);
  line-height: 1.3;
}
.usecase-mock--briefing .b-card .src {
  font-size: 9px;
  color: var(--ink3);
  margin-top: 2px;
}

/* Variant-specific floating chip: topic graph match indicator */
.usecase-quote.usecase-quote--chip {
  width: auto;
  max-width: none;
  padding: 12px 16px;
  transform: rotate(-2deg);
}
.usecase-quote--chip .chip-title {
  font-family: system-ui;
  font-size: 12px;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 6px;
}
.usecase-quote--chip .chip-title .pulse {
  display: inline-block;
  width: 7px; height: 7px;
  border-radius: 50%;
  background: #1a9e75;
  box-shadow: 0 0 0 3px rgba(26,158,117,0.18);
}
.usecase-quote--chip .topics {
  display: flex;
  gap: 5px;
  flex-wrap: wrap;
}
.usecase-quote--chip .topic {
  display: inline-block;
  font-size: 10.5px;
  background: var(--violet-light);
  color: var(--violet);
  padding: 2px 8px;
  border-radius: 999px;
  font-weight: 500;
}

/* ── Variant: Teams ,  Shared paper with collaborator highlights ── */
.usecase-mock--shared {
  padding: 22px 22px 14px;
  display: flex;
  flex-direction: column;
  gap: 9px;
}
.usecase-mock--shared .doc-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 6px;
}
.usecase-mock--shared .doc-title-mock {
  font-family: Georgia, serif;
  font-size: 13px;
  color: var(--ink);
  margin: 0;
}
.usecase-mock--shared .who {
  display: inline-flex;
}
.usecase-mock--shared .who .av {
  width: 18px; height: 18px;
  border-radius: 50%;
  border: 2px solid var(--paper);
  margin-left: -5px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 8.5px;
  font-weight: 700;
  color: #fff;
}
.usecase-mock--shared .who .av:first-child { margin-left: 0; }
.usecase-mock--shared .who .av-r { background: #5b4fcf; }
.usecase-mock--shared .who .av-m { background: #1a9e75; }
.usecase-mock--shared .who .av-j { background: #b97318; }
.usecase-mock--shared .line {
  height: 7px;
  border-radius: 2px;
  background: rgba(15,14,17,0.10);
}
.usecase-mock--shared .line.short { width: 60%; }
.usecase-mock--shared .line.med { width: 84%; }
.usecase-mock--shared .line.long { width: 96%; }
.usecase-mock--shared .line.hl-r { background: rgba(91,79,207,0.55); width: 72%; }
.usecase-mock--shared .line.hl-m { background: rgba(26,158,117,0.55); width: 80%; }

/* Variant-specific floating chip: comment thread */
.usecase-quote.usecase-quote--thread {
  padding: 14px 16px 12px;
  transform: rotate(-1.2deg);
}
.usecase-quote--thread .thread-comment {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 8px;
  align-items: start;
  margin-bottom: 9px;
}
.usecase-quote--thread .thread-comment:last-child { margin-bottom: 0; }
.usecase-quote--thread .av {
  width: 22px; height: 22px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 9.5px;
  font-weight: 700;
  color: #fff;
  flex-shrink: 0;
  margin-top: 1px;
}
.usecase-quote--thread .av.av-m { background: #1a9e75; }
.usecase-quote--thread .av.av-j { background: #b97318; }
.usecase-quote--thread .thread-comment .who {
  font-family: system-ui;
  font-size: 11px;
  font-weight: 600;
  color: var(--ink);
}
.usecase-quote--thread .thread-comment .when {
  font-family: system-ui;
  font-size: 10px;
  color: var(--ink3);
  margin-left: 6px;
  font-weight: 400;
}
.usecase-quote--thread .thread-comment .body {
  font-family: system-ui;
  font-size: 11.5px;
  line-height: 1.45;
  color: var(--ink2);
  margin-top: 1px;
}

/* ────────────────────────────────────────────────────────────────────
   Variant A ,  Researchers: scattered floating "feed" cards
   ────────────────────────────────────────────────────────────────────
   3-4 small cards positioned absolute at slight rotations across the
   lower half of the visual, with a tag label + a few mock text lines.
   Replaces the single big briefing list with a diverse layout. */
.usecase-scatter {
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.scatter-card {
  position: absolute;
  background: var(--paper);
  border-radius: 6px;
  padding: 12px 14px 14px;
  box-shadow:
    0 18px 36px rgba(15,14,17,0.10),
    0 2px 6px rgba(15,14,17,0.05);
  width: 22%;
  min-width: 180px;
}
.scatter-card .tag {
  font-family: system-ui;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink3);
  margin-bottom: 9px;
}
.scatter-card .tag.violet {
  color: var(--violet);
}
.scatter-card .tag .dot {
  display: inline-block;
  width: 5px; height: 5px;
  border-radius: 50%;
  background: currentColor;
  vertical-align: middle;
  margin-right: 6px;
  transform: translateY(-1px);
}
.scatter-card .row {
  height: 8px;
  border-radius: 2px;
  background: rgba(15,14,17,0.10);
  margin-bottom: 7px;
}
.scatter-card .row.short { width: 55%; }
.scatter-card .row.med { width: 80%; }
.scatter-card .row.long { width: 96%; }
.scatter-card .row:last-child { margin-bottom: 0; }
/* Position + rotation per card ,  places them across the lower 60% of the
   visual, just like the reference image. */
.scatter-card.c1 { left: 12%; top: 48%; transform: rotate(-3.5deg); }
.scatter-card.c2 { left: 38%; top: 42%; transform: rotate(1.2deg); }
.scatter-card.c3 { left: 64%; top: 50%; transform: rotate(-1.8deg); }

/* ────────────────────────────────────────────────────────────────────
   Variant B ,  Students: single big centered "Verified citation" card
   ────────────────────────────────────────────────────────────────────
   Mirrors the Clinicians reference: one large centered card with a
   violet "VERIFIED CITATION" header row, a big serif quote, a thin
   divider, then journal · year + author on a single line. */
.usecase-citation {
  position: absolute;
  left: 14%;
  right: 14%;
  bottom: 14%;
  background: var(--paper);
  border-radius: 8px;
  padding: 26px 32px 22px;
  box-shadow:
    0 28px 56px rgba(15,14,17,0.12),
    0 3px 8px rgba(15,14,17,0.05);
}
.usecase-citation .vc-head {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-family: system-ui;
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--violet);
  margin-bottom: 14px;
}
.usecase-citation .vc-head svg { display: block; }
.usecase-citation .vc-quote {
  font-family: Georgia, serif;
  font-weight: 400;
  font-size: clamp(20px, 2.2vw, 26px);
  line-height: 1.32;
  color: var(--ink);
  margin: 0 0 22px;
  position: relative;
  padding-left: 18px;
}
.usecase-citation .vc-quote::before {
  content: '\201C';
  position: absolute;
  left: 0; top: -4px;
  font-family: Georgia, serif;
  font-size: 28px;
  color: var(--violet);
  line-height: 1;
}
.usecase-citation .vc-meta {
  border-top: 1px solid var(--border2);
  padding-top: 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: system-ui;
  font-size: 13.5px;
  color: var(--ink2);
}
.usecase-citation .vc-meta .src { font-weight: 500; color: var(--ink); }
.usecase-citation .vc-meta .author { color: var(--ink3); }

/* ────────────────────────────────────────────────────────────────────
   Variant C ,  Teams: overlapping note cards w/ collaborator avatars
   ────────────────────────────────────────────────────────────────────
   3 small cards stacked diagonally with avatar bubbles attached to each.
   Reads as "multiple researchers contributing notes to a shared paper."
   Different rhythm from the scatter layout ,  more compact, more
   intentional staircase composition. */
.usecase-stack {
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.stack-card {
  position: absolute;
  background: var(--paper);
  border-radius: 7px;
  padding: 12px 14px 14px;
  box-shadow:
    0 18px 38px rgba(15,14,17,0.10),
    0 2px 6px rgba(15,14,17,0.05);
  width: 32%;
  min-width: 220px;
}
.stack-card .head {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 10px;
}
.stack-card .av {
  width: 22px; height: 22px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-family: system-ui;
  font-size: 10.5px;
  font-weight: 700;
  flex-shrink: 0;
}
.stack-card .av-m { background: #1a9e75; }
.stack-card .av-r { background: var(--violet); }
.stack-card .av-j { background: #b97318; }
.stack-card .who {
  font-family: system-ui;
  font-size: 11.5px;
  font-weight: 600;
  color: var(--ink);
  line-height: 1;
}
.stack-card .when {
  font-family: system-ui;
  font-size: 10px;
  color: var(--ink3);
  margin-left: auto;
}
.stack-card .body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text", sans-serif;
  font-size: 13px;
  line-height: 1.5;
  color: var(--ink2);
  margin: 0 0 8px;
}
.stack-card .anchor {
  font-family: system-ui;
  font-size: 10.5px;
  color: var(--violet);
  background: var(--violet-light);
  padding: 2px 7px;
  border-radius: 3px;
  display: inline-block;
}

.stack-card.s1 { left: 8%;  top: 30%; transform: rotate(-3deg);  z-index: 1; }
.stack-card.s2 { left: 32%; top: 48%; transform: rotate(1.5deg); z-index: 2; }
.stack-card.s3 { left: 58%; top: 36%; transform: rotate(-1.2deg); z-index: 3; }

/* Hide the old silhouette + play affordances ,  superseded by the mock */
.usecase-figure { display: none; }
.usecase-play   { display: none; }

/* ── Caption below the visual ── */
.usecase-caption {
  margin-top: 24px;
  max-width: 380px;
}
.usecase-caption .label {
  font-size: 14.5px;
  font-weight: 500;
  color: var(--ink);
  margin: 0 0 6px;
}
.usecase-caption .desc {
  font-size: 13.5px;
  line-height: 1.55;
  color: var(--ink2);
  margin: 0 0 16px;
}
.usecase-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 13.5px;
  font-weight: 500;
  color: var(--ink);
  text-decoration: none;
}
.usecase-link svg {
  width: 14px; height: 14px;
  transition: transform 200ms ease;
}
.usecase-link:hover svg { transform: translateX(3px); }

/* ── Nav (chevrons) ── */
.usecases-nav {
  display: flex;
  gap: 6px;
  margin-top: 28px;
  padding: 0 48px;
  align-items: center;
  max-width: 1280px;
  margin-left: auto;
  margin-right: auto;
}
.usecases-nav-spacer { flex: 1; }
.usecases-nav-pill {
  display: inline-flex;
  gap: 0;
  align-items: center;
  background: var(--paper2);
  border-radius: 999px;
  padding: 6px;
}
.usecases-nav button {
  width: 38px; height: 38px;
  border: none;
  background: transparent;
  border-radius: 50%;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  color: var(--ink2);
  transition: background 160ms ease, color 160ms ease;
}
.usecases-nav button:hover { background: var(--paper3, #e8e4dc); color: var(--ink); }
.usecases-nav button:disabled {
  color: var(--ink3);
  cursor: not-allowed;
  background: transparent;
}
.usecases-nav svg { width: 16px; height: 16px; }