:root {
  --bg: #f7f4ee;
  --panel: #ffffff;
  --ink: #1d232a;
  --muted: #6b7280;
  --accent: #136f63;
  --border: #e2ded4;
  --shadow: 0 18px 45px rgba(20, 24, 31, 0.12);
}
* {
  box-sizing: border-box;
}
body {
  margin: 0;
  font-family: "Zen Kaku Gothic New", "Noto Sans JP", "BIZ UDPGothic", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 8%, rgba(250, 246, 235, 0.95), rgba(247, 243, 233, 0.6) 45%),
    linear-gradient(180deg, #f8f5ef 0%, #efe9dd 100%);
}
main {
  max-width: 980px;
  margin: 0 auto;
  padding: 28px 20px 60px;
}
header {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 18px 22px;
  box-shadow: var(--shadow);
  margin-bottom: 22px;
}
.back-link {
  margin: 0 0 10px;
  font-size: 14px;
}
.back-link a {
  color: var(--accent);
  font-weight: 600;
  text-decoration: none;
}
.back-link a:hover {
  text-decoration: underline;
}
h1 {
  margin: 0 0 6px;
  font-size: 26px;
  letter-spacing: 0.02em;
}
h2 {
  margin-top: 32px;
  margin-bottom: 12px;
  font-size: 20px;
  border-left: 6px solid var(--accent);
  padding-left: 10px;
}
h3 {
  margin-top: 18px;
  margin-bottom: 8px;
  font-size: 16px;
  color: #111827;
}
h4 {
  margin: 14px 0 6px;
  font-size: 14px;
  color: #1f2937;
}
p {
  margin: 0 0 10px;
  line-height: 1.7;
}
ul, ol {
  margin: 0 0 10px 18px;
  padding: 0;
  line-height: 1.7;
}
li {
  margin-bottom: 6px;
}
code {
  background: #f1efe8;
  padding: 2px 6px;
  border-radius: 6px;
  font-size: 0.95em;
}
hr {
  border: none;
  border-top: 1px dashed var(--border);
  margin: 22px 0;
}
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px 18px;
  box-shadow: 0 10px 30px rgba(30, 33, 42, 0.08);
  margin-bottom: 16px;
}
.caption {
  font-size: 12px;
  color: var(--muted);
  margin-top: 6px;
}
img {
  max-width: 100%;
  border-radius: 12px;
  border: 1px solid var(--border);
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.08);
  margin: 8px 0 6px;
}
.muted {
  color: var(--muted);
  font-size: 13px;
}