:root {
  --ink: #1c1b19;
  --ink-soft: #3d3b38;
  --muted: #8b877f;
  --bg: #fbfaf8;
  --card: #ffffff;
  --line: #e6e3dc;
  --line-soft: #f0ede7;
  --accent: #2f4a3f;
}

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Hiragino Sans", "Yu Gothic", "Noto Sans JP", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.95;
  letter-spacing: 0.02em;
  -webkit-font-smoothing: antialiased;
}

.serif {
  font-family: "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", "Noto Serif JP", serif;
}

/* ---------- header ---------- */
header.site {
  background: var(--card);
  border-bottom: 1px solid var(--line);
  padding: 40px 20px 26px;
  text-align: center;
}
header.site .logo {
  font-family: "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", serif;
  font-size: 25px;
  font-weight: 600;
  letter-spacing: 0.22em;
  color: var(--ink);
  text-decoration: none;
  display: inline-block;
  text-indent: 0.22em;
}
header.site .tagline {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 12px;
  letter-spacing: 0.16em;
}
header.site .tagline::before,
header.site .tagline::after {
  content: "";
  display: inline-block;
  width: 24px;
  height: 1px;
  background: var(--line);
  vertical-align: middle;
  margin: 0 12px;
}

nav.site {
  margin-top: 22px;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 28px;
  font-size: 13px;
  letter-spacing: 0.1em;
}
nav.site a {
  color: var(--ink-soft);
  text-decoration: none;
  padding-bottom: 3px;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s;
}
nav.site a:hover { border-bottom-color: var(--ink); }

.ad-notice {
  color: var(--muted);
  text-align: center;
  font-size: 11px;
  letter-spacing: 0.08em;
  padding: 10px 12px;
  border-bottom: 1px solid var(--line-soft);
}

/* ---------- layout ---------- */
main {
  max-width: 680px;
  margin: 0 auto;
  padding: 64px 24px 88px;
}

h1 {
  font-family: "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", serif;
  font-size: 27px;
  font-weight: 600;
  line-height: 1.65;
  letter-spacing: 0.04em;
  margin: 0 0 28px;
}
h2 {
  font-family: "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", serif;
  font-size: 20px;
  font-weight: 600;
  letter-spacing: 0.05em;
  margin: 3em 0 1em;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}
h3 { font-size: 16.5px; letter-spacing: 0.04em; margin: 2.4em 0 0.8em; }

p { margin: 0 0 1.6em; }
a { color: var(--accent); text-underline-offset: 3px; }

ul, ol { padding-left: 1.3em; margin: 0 0 1.8em; }
li { margin-bottom: 0.6em; }

strong { font-weight: 600; }

.post-meta {
  color: var(--muted);
  font-size: 12px;
  letter-spacing: 0.14em;
  margin-bottom: 18px;
}

/* ---------- index list ---------- */
.card-list { list-style: none; padding: 0; margin: 0; }
.card {
  padding: 30px 0;
  border-bottom: 1px solid var(--line);
}
.card:first-child { padding-top: 0; }
.card .date {
  display: block;
  color: var(--muted);
  font-size: 11.5px;
  letter-spacing: 0.14em;
  margin-bottom: 10px;
}
.card a.title {
  font-family: "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", serif;
  font-size: 19px;
  font-weight: 600;
  line-height: 1.6;
  letter-spacing: 0.03em;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s;
}
.card a.title:hover { border-bottom-color: var(--ink); }
.card p {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- notes & buttons ---------- */
.pr-note {
  font-size: 12px;
  color: var(--muted);
  letter-spacing: 0.04em;
  padding: 12px 0;
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
  margin-bottom: 2.4em;
}

.btn-rakuten {
  display: inline-block;
  background: var(--ink);
  color: #fff;
  padding: 15px 34px;
  text-decoration: none;
  font-size: 14px;
  letter-spacing: 0.08em;
  transition: opacity 0.2s;
}
.btn-rakuten:hover { opacity: 0.82; }

table {
  border-collapse: collapse;
  width: 100%;
  font-size: 14px;
  margin: 0 0 2em;
}
th, td {
  border-bottom: 1px solid var(--line);
  padding: 13px 12px;
  text-align: left;
}
th {
  font-weight: 600;
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--ink-soft);
  border-bottom: 1px solid var(--ink);
}

/* ---------- author card ---------- */
.author-card {
  margin-top: 72px;
  padding-top: 28px;
  border-top: 1px solid var(--ink);
  font-size: 13.5px;
  line-height: 1.9;
}
.author-card .name {
  font-family: "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", serif;
  font-weight: 600;
  font-size: 16px;
  letter-spacing: 0.08em;
  color: var(--ink);
  margin: 0 0 10px;
}
.author-card p { margin: 0 0 8px; color: var(--muted); }
.author-card a { font-size: 13px; }

/* ---------- footer ---------- */
footer.site {
  border-top: 1px solid var(--line);
  padding: 44px 24px 56px;
  text-align: center;
  color: var(--muted);
  font-size: 11.5px;
  line-height: 2;
  letter-spacing: 0.04em;
  background: var(--card);
}
footer.site p { margin: 3px 0; }

nav.social {
  display: flex;
  justify-content: center;
  gap: 26px;
  margin-bottom: 26px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--line-soft);
  font-size: 12px;
  letter-spacing: 0.16em;
}
nav.social a {
  color: var(--ink-soft);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: border-color 0.2s;
}
nav.social a:hover { border-bottom-color: var(--ink); }

@media (max-width: 600px) {
  main { padding: 44px 20px 64px; }
  header.site { padding: 30px 18px 22px; }
  header.site .logo { font-size: 20px; letter-spacing: 0.16em; }
  h1 { font-size: 22px; }
  h2 { font-size: 18px; }
  nav.site { gap: 20px; }
}