:root {
  --ink: #10253c;
  --muted: #506070;
  --line: #d8e0e7;
  --bg: #f6f8fb;
  --card: #ffffff;
  --accent: #2f5e4e;
  --accent-ink: #ffffff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Noto Sans JP', sans-serif;
  color: var(--ink);
  background: var(--bg);
}

.case-wrap {
  width: min(1200px, 92vw);
  margin: 0 auto;
}

.case-topbar {
  background: #0f2b4a;
  color: #fff;
  font-size: 0.95rem;
}

.case-topbar .case-wrap {
  display: flex;
  gap: 14px;
  align-items: center;
  min-height: 48px;
}

.case-topbar a {
  color: #fff;
  text-decoration: none;
  opacity: 0.92;
}

.case-topbar a:hover {
  opacity: 1;
}

.case-hero {
  background: linear-gradient(135deg, #eef4f2 0%, #dde8e4 100%);
  border-bottom: 1px solid #cfd9d3;
}

.case-hero .case-wrap {
  padding: 34px 0 30px;
}

.case-hero h1 {
  margin: 0;
  font-size: clamp(1.8rem, 3.2vw, 2.7rem);
  line-height: 1.35;
}

.case-hero p {
  margin: 12px 0 0;
  color: #2f475c;
  line-height: 1.85;
  font-size: clamp(0.95rem, 1.4vw, 1.07rem);
}

.case-tools {
  margin: 24px auto 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.case-chip {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  padding: 8px 14px;
  border: 1px solid #bfccd8;
  border-radius: 999px;
  background: #fff;
  color: #203447;
  font-size: 0.9rem;
  font-weight: 700;
}

.case-chip:hover {
  border-color: #8ea2b7;
}

.case-chip.is-active {
  background: #183c61;
  color: #fff;
  border-color: #183c61;
}

.case-section {
  margin: 34px auto;
}

.case-section h2 {
  margin: 0 0 14px;
  font-size: clamp(1.3rem, 2.1vw, 1.75rem);
}

.case-section p {
  margin: 0;
  color: var(--muted);
  line-height: 1.8;
}

.category-grid {
  margin-top: 18px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.category-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.category-card img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  display: block;
}

.category-card__body {
  padding: 14px;
}

.category-card__body h3 {
  margin: 0;
  font-size: 1.05rem;
}

.category-card__body p {
  margin-top: 8px;
  font-size: 0.93rem;
  line-height: 1.7;
  color: #415265;
}

.category-card__body a {
  margin-top: 12px;
  display: inline-flex;
  text-decoration: none;
  padding: 9px 12px;
  border-radius: 8px;
  background: var(--accent);
  color: var(--accent-ink);
  font-weight: 700;
  font-size: 0.9rem;
}

.case-grid {
  margin-top: 16px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.case-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
}

.case-card img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  display: block;
}

.case-card__body {
  padding: 12px 13px 14px;
}

.case-tag {
  display: inline-flex;
  margin-bottom: 8px;
  padding: 4px 8px;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 700;
  background: #e8eef5;
  color: #28435e;
}

.case-card h3 {
  margin: 0;
  font-size: 1rem;
}

.case-card p {
  margin-top: 7px;
  font-size: 0.9rem;
  line-height: 1.72;
  color: #415265;
}

.case-footer {
  margin: 36px 0 48px;
  padding: 16px;
  border: 1px solid #d4dde5;
  background: #fff;
  border-radius: 12px;
  text-align: center;
}

.case-footer a {
  display: inline-flex;
  margin-top: 10px;
  text-decoration: none;
  padding: 10px 14px;
  border-radius: 8px;
  background: #17385b;
  color: #fff;
  font-weight: 700;
}

@media (max-width: 960px) {
  .category-grid,
  .case-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 620px) {
  .case-hero .case-wrap {
    padding: 24px 0 22px;
  }

  .category-grid,
  .case-grid {
    grid-template-columns: 1fr;
  }

  /* Category detail pages: show image thumbnails in 3 columns on mobile */
  .case-grid--mobile-3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 8px;
  }

  .case-grid--mobile-3 .case-card {
    border-radius: 8px;
  }

  .case-grid--mobile-3 .case-card img {
    aspect-ratio: 1 / 1;
  }

  .case-grid--mobile-3 .case-card__body {
    display: none;
  }

  .case-topbar .case-wrap {
    min-height: 42px;
    font-size: 0.88rem;
  }
}