.back-link {
  display: inline-block;
  font-size: 13px;
  color: var(--ink-soft);
  margin-bottom: 20px;
}
.back-link:hover { color: var(--ink); }

.case-hero { padding: 56px 0 40px; }

.case-tag {
  color: var(--accent);
  font-weight: 700;
  font-size: 13px;
  letter-spacing: 0.04em;
  margin: 0 0 10px;
}

.case-hero h1 {
  font-size: clamp(24px, 4vw, 34px);
  margin: 0;
  font-weight: 700;
}

.case-brief { padding: 0 0 56px; }

.case-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.case-info h2, .case-points h2 {
  font-size: 16px;
  margin: 0 0 16px;
}

.case-info dl {
  margin: 0;
  border-top: 1px solid var(--border);
}
.case-info dt {
  font-size: 12px;
  color: var(--ink-soft);
  padding-top: 14px;
}
.case-info dd {
  margin: 4px 0 0;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border);
  font-size: 14px;
}

.case-points ul {
  margin: 0;
  padding-left: 18px;
  font-size: 14px;
  color: var(--ink-soft);
}
.case-points li { margin-bottom: 10px; }

/* 改善提案 */
.case-improve { padding: 0 0 64px; }

.case-improve h2 {
  font-size: 16px;
  margin: 0 0 12px;
}

.improve-lead {
  font-size: 14px;
  color: var(--ink-soft);
  max-width: 720px;
  margin: 0 0 28px;
}

.improve-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.improve-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 22px 20px;
  display: flex;
  flex-direction: column;
}

.improve-num {
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.08em;
  margin: 0 0 8px;
}

.improve-card h3 {
  font-size: 15px;
  margin: 0 0 10px;
}

.improve-card p {
  font-size: 13px;
  color: var(--ink-soft);
  margin: 0 0 12px;
}

.improve-metric {
  margin-top: auto;
  font-size: 12px;
  font-weight: 700;
  color: var(--ink);
  background: var(--accent-soft);
  border-radius: 6px;
  padding: 8px 12px;
}
.improve-card p.improve-metric { margin-bottom: 0; }

.case-preview { padding: 0 0 80px; }

.preview-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}
.preview-bar span {
  font-size: 13px;
  font-weight: 700;
  color: var(--ink-soft);
}

.btn-outline {
  display: inline-block;
  padding: 8px 18px;
  border-radius: 999px;
  border: 1px solid var(--border);
  font-size: 13px;
}
.btn-outline:hover { border-color: var(--ink); }

.preview-frame {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: #fff;
}

.preview-frame iframe {
  width: 100%;
  height: 760px;
  border: 0;
  display: block;
}

@media (max-width: 720px) {
  .case-grid { grid-template-columns: 1fr; }
  .improve-grid { grid-template-columns: 1fr; }
  .preview-frame iframe { height: 560px; }
}