:root {
  --bg: #ffffff;
  --ink: #0a0a0a;
  --ink-soft: #222222;
  --ink-muted: #9aa0a8;
  --rule: #ececec;
  --accent: #2547e6;
  --accent-soft: #6488ff;
  --accent-deep: #1730a8;
  --max: 1200px;
}

*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  letter-spacing: -0.005em;
}

a { color: inherit; }

.case-study {
  max-width: var(--max);
  margin: 0 auto;
  padding: 96px 48px 120px;
}

.hero-image {
  width: 100%;
  aspect-ratio: 16 / 8;
  border-radius: 28px;
  background: #f4f6fb;
  display: block;
  margin-bottom: 64px;
  overflow: hidden;
  box-shadow: 0 1px 2px rgba(10, 10, 30, 0.04), 0 12px 40px rgba(10, 30, 90, 0.06);
}

.hero-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  display: block;
}

.case-title {
  font-size: clamp(36px, 4.5vw, 56px);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.08;
  margin-bottom: 64px;
  max-width: 22ch;
}

.meta-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  padding-bottom: 88px;
  border-bottom: 1px solid var(--rule);
  margin-bottom: 88px;
}

.meta-item dt {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--accent);
  margin-bottom: 14px;
}
.meta-item dd {
  font-size: 15px;
  line-height: 1.5;
  color: var(--ink);
}

.case-body {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 96px;
  align-items: start;
}

.section-nav {
  position: sticky;
  top: 96px;
}
.section-nav ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.section-nav a {
  position: relative;
  display: flex;
  align-items: center;
  color: var(--ink-muted);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  padding-left: 18px;
  line-height: 1.4;
  transition: color 0.2s ease;
}
.section-nav a:hover { color: var(--ink-soft); }
.section-nav a .dot {
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--ink);
  opacity: 0;
  transition: opacity 0.2s ease;
}
.section-nav a.active {
  color: var(--ink);
}
.section-nav a.active .dot {
  opacity: 1;
}

.case-content section {
  margin-bottom: 112px;
  scroll-margin-top: 80px;
}
.case-content section:last-child { margin-bottom: 0; }

.section-label {
  color: var(--accent);
  font-size: 16px;
  font-weight: 500;
  margin-bottom: 18px;
}

.case-content h2 {
  font-size: clamp(28px, 3vw, 40px);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.12;
  margin-bottom: 28px;
  max-width: 22ch;
}

.case-content .section-subtitle {
  color: var(--ink);
  font-size: 20px;
  font-weight: 600;
  line-height: 1.35;
  max-width: 42ch;
  margin: -10px 0 28px;
}

.case-content p {
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink-soft);
  max-width: 62ch;
  margin-bottom: 24px;
}
.case-content p + p { margin-top: -4px; }

.media-block {
  margin: 40px 0 0;
  border-radius: 24px;
  overflow: hidden;
  background: linear-gradient(135deg, var(--accent-soft) 0%, var(--accent) 70%, var(--accent-deep) 100%);
  aspect-ratio: 16 / 10;
  display: flex;
  align-items: center;
  justify-content: center;
}
.media-block.soft {
  background: linear-gradient(135deg, #eef2ff 0%, #dbe4ff 100%);
}
.media-placeholder {
  color: rgba(255, 255, 255, 0.85);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.media-block.soft .media-placeholder {
  color: #6b7aa8;
}

.playtest-findings {
  max-width: 760px;
  margin: 34px 0 0;
}

.finding-group + .finding-group {
  margin-top: 34px;
}

.finding-group h3 {
  margin-bottom: 14px;
  color: var(--accent);
  font-size: 15px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.finding-group ul {
  display: grid;
  gap: 12px;
  padding-left: 20px;
}

.finding-group li {
  color: var(--ink-soft);
  font-size: 16px;
  line-height: 1.6;
}

.interview-accordion {
  max-width: 720px;
  margin: 32px 0 0;
  border: 1px solid var(--rule);
  border-radius: 12px;
  background: #fbfcff;
  overflow: hidden;
}

.interview-accordion summary {
  cursor: pointer;
  padding: 16px 18px;
  color: var(--ink);
  font-size: 15px;
  font-weight: 600;
  list-style-position: inside;
}

.interview-accordion summary:hover {
  background: #f4f6fb;
}

.interview-content {
  max-height: 620px;
  overflow: auto;
  padding: 4px 22px 24px;
  border-top: 1px solid var(--rule);
}

.interview-content h3 {
  margin: 28px 0 14px;
  color: var(--accent);
  font-size: 15px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.interview-content h3:first-child {
  margin-top: 20px;
}

.interview-content h4 {
  margin: 20px 0 8px;
  color: var(--ink);
  font-size: 16px;
  font-weight: 700;
  line-height: 1.45;
}

.case-content .interview-content p {
  max-width: none;
  margin-bottom: 8px;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.55;
}

.decision-pages {
  max-width: 960px;
  margin-top: 46px;
}

.decision-page + .decision-page {
  margin-top: 64px;
}

.decision-page h3 {
  margin-bottom: 22px;
  color: var(--accent);
  font-size: 16px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.feature-list {
  display: grid;
  gap: 36px;
}

.feature-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  align-items: start;
  padding-bottom: 34px;
  border-bottom: 1px solid var(--rule);
}

.feature-item:has(.feature-image) {
  grid-template-columns: minmax(220px, 0.9fr) minmax(260px, 1.1fr);
  gap: 18px 36px;
}

.feature-item-wide {
  grid-template-columns: minmax(0, 1fr);
}

.feature-item-wide:has(.feature-image) {
  grid-template-columns: minmax(0, 1fr);
}

.feature-item h4 {
  margin-bottom: 0;
  color: var(--ink);
  font-size: 20px;
  font-weight: 700;
  line-height: 1.25;
}

.case-content .feature-item p {
  max-width: 48ch;
  margin-bottom: 0;
  font-size: 16px;
}

.feature-item:has(.feature-image) h4,
.feature-item:has(.feature-image) p {
  grid-column: 1;
}

.feature-item:has(.feature-image) .feature-image {
  grid-column: 2;
  grid-row: 1 / span 2;
  align-self: center;
}

.feature-item-wide:has(.feature-image) h4,
.feature-item-wide:has(.feature-image) p,
.feature-item-wide:has(.feature-image) .feature-image {
  grid-column: 1;
}

.feature-item-wide:has(.feature-image) .feature-image {
  grid-row: auto;
  margin-top: 8px;
  max-width: 760px;
  justify-self: center;
}

.feature-image-placeholder {
  width: 100%;
  aspect-ratio: 4 / 3;
  border: 1px dashed #c8d2f0;
  border-radius: 16px;
  background: #f7f9ff;
  color: #6b7aa8;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 18px;
  text-align: center;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1.4;
  text-transform: uppercase;
}

.feature-image,
.section-feature-image {
  width: 100%;
  height: auto;
  display: block;
  object-fit: contain;
}

.section-feature-image {
  max-width: 360px;
  margin: -4px auto 32px;
}

.feature-image-small {
  width: 72%;
  justify-self: center;
}

.feature-image-tiny {
  width: 58%;
}

.feature-item-compact .feature-image:not(.feature-image-small) {
  max-width: 280px;
  justify-self: center;
}

.iteration-accordion {
  margin: 40px 0 0;
  border-top: 1px solid var(--rule);
}

.iteration-accordion:last-of-type {
  border-bottom: 1px solid var(--rule);
}

.iteration-accordion summary {
  cursor: pointer;
  list-style: none;
  padding: 28px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  transition: color 0.15s ease;
}

.iteration-accordion summary::-webkit-details-marker { display: none; }
.iteration-accordion summary::marker { display: none; }

.iteration-accordion summary:hover .iteration-accordion-title {
  color: var(--accent);
}

.iteration-accordion-heading {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
}

.iteration-accordion-label {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--accent);
}

.iteration-accordion-title {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.015em;
  color: var(--ink);
  line-height: 1.25;
  transition: color 0.15s ease;
}

.iteration-accordion-toggle {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  border: 1px solid var(--rule);
  border-radius: 50%;
  position: relative;
  transition: transform 0.25s ease, border-color 0.15s ease;
}

.iteration-accordion-toggle::before,
.iteration-accordion-toggle::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  background: var(--ink);
  transition: opacity 0.2s ease;
}

.iteration-accordion-toggle::before {
  width: 10px;
  height: 1.5px;
  transform: translate(-50%, -50%);
}

.iteration-accordion-toggle::after {
  width: 1.5px;
  height: 10px;
  transform: translate(-50%, -50%);
}

.iteration-accordion[open] .iteration-accordion-toggle::after {
  opacity: 0;
}

.iteration-accordion summary:hover .iteration-accordion-toggle {
  border-color: var(--accent);
}

.iteration-accordion-body {
  padding: 8px 0 48px;
}

.iteration-accordion[open] .iteration-accordion-body {
  animation: iteration-reveal 0.35s ease-out both;
}

@keyframes iteration-reveal {
  from {
    opacity: 0;
    transform: translateY(-6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.iteration-screens {
  max-width: 960px;
  margin-top: 8px;
}

.iteration-screen + .iteration-screen {
  margin-top: 88px;
}

.iteration-screen h3 {
  margin-bottom: 22px;
  color: var(--accent);
  font-size: 16px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.iteration-screen-image {
  width: 100%;
  border-radius: 16px;
  overflow: hidden;
  background: #f4f6fb;
  border: 1px solid var(--rule);
  margin-bottom: 28px;
  box-shadow: 0 1px 2px rgba(10, 10, 30, 0.04), 0 12px 32px rgba(10, 30, 90, 0.06);
}

.iteration-screen-image img {
  width: 100%;
  height: auto;
  display: block;
}

.case-content .iteration-screen > p {
  max-width: 62ch;
  margin-bottom: 32px;
}

.iteration-changes {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 36px;
  padding-top: 28px;
  border-top: 1px solid var(--rule);
}

.change-col h4 {
  margin-bottom: 14px;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
}

.change-col.change-kept h4 { color: var(--accent); }
.change-col.change-new h4 { color: var(--ink); }
.change-col.change-cut h4 { color: var(--ink-muted); }

.change-col ul {
  list-style: none;
  padding: 0;
  display: grid;
  gap: 10px;
}

.change-col li {
  position: relative;
  padding-left: 14px;
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.55;
}

.change-col li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 1px;
  background: var(--ink-muted);
}

.change-col.change-cut li {
  color: var(--ink-muted);
}

.impact-pillars {
  margin-top: 40px;
  max-width: 760px;
}

.impact-pillar {
  padding: 36px 0;
  border-top: 1px solid var(--rule);
}

.impact-pillar:last-child {
  border-bottom: 1px solid var(--rule);
}

.case-content .impact-pillar p.impact-pillar-label {
  margin: 0 0 12px;
  max-width: none;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--accent);
}

.case-content .impact-pillar h3 {
  margin: 0 0 14px;
  color: var(--ink);
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.015em;
  line-height: 1.3;
  max-width: 32ch;
  text-transform: none;
}

.case-content .impact-pillar p {
  margin-bottom: 0;
}

.demo-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 8px 0 20px;
}

.demo-button {
  appearance: none;
  border: 1px solid var(--ink);
  border-radius: 8px;
  background: var(--ink);
  color: var(--bg);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 0 16px;
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  line-height: 1;
  text-decoration: none;
  transition: background 0.2s ease, color 0.2s ease, transform 0.2s ease;
}

.demo-button:hover {
  background: var(--accent);
  border-color: var(--accent);
}

.demo-button:active {
  transform: translateY(1px);
}

.demo-frame {
  width: 100%;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--rule);
  border-radius: 24px;
  overflow: hidden;
  background: #f4f6fb;
  box-shadow: 0 1px 2px rgba(10, 10, 30, 0.04), 0 16px 44px rgba(10, 30, 90, 0.08);
}

.demo-frame iframe {
  width: 100%;
  height: 100%;
  border: 0;
  display: block;
  background: #ffffff;
}

.figma-frame {
  margin: 8px 0 32px;
}

.demo-frame:fullscreen {
  aspect-ratio: auto;
  border-radius: 0;
  border: 0;
}

@media (max-width: 960px) {
  .case-study { padding: 88px 28px 96px; }
  .hero-image { aspect-ratio: 16 / 9; border-radius: 22px; margin-bottom: 48px; }
  .case-title { margin-bottom: 48px; }
  .meta-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 28px 24px;
    padding-bottom: 56px;
    margin-bottom: 56px;
  }
  .case-body {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .section-nav {
    position: static;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--rule);
  }
  .section-nav ul {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 10px 20px;
  }
  .section-nav a { padding-left: 0; }
  .section-nav a .dot { display: none; }
  .case-content section { margin-bottom: 80px; }
  .feature-item,
  .feature-item:has(.feature-image) { grid-template-columns: 1fr; }
  .feature-item:has(.feature-image) .feature-image {
    grid-column: 1;
    grid-row: auto;
    margin-top: 8px;
  }
  .feature-image-placeholder,
  .feature-image { max-width: 420px; }
  .feature-image-small { width: 78%; justify-self: start; }
  .demo-frame { aspect-ratio: 4 / 5; border-radius: 18px; }
  .iteration-changes { grid-template-columns: 1fr; gap: 28px; }
}

@media (max-width: 520px) {
  .case-study { padding: 80px 20px 80px; }
  .meta-grid { grid-template-columns: 1fr; gap: 22px; }
  .hero-mark { gap: 18px; }
}