/* 調査ノート風・1カラム。角丸なし、罫線でメリハリをつける */
:root {
  --paper: #f6f3ea;
  --ink: #1e2638;
  --ink-soft: #4a5268;
  --accent: #b8472a;
  --sand: #e6dfcc;
  --serif: "Yu Mincho", "YuMincho", "Hiragino Mincho ProN", "Noto Serif JP", serif;
  --sans: "Yu Gothic", "YuGothic", "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
}

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

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-weight: 500;
  font-size: 16px;
  line-height: 1.9;
  overflow-wrap: anywhere;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--accent); text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }

.nb-wrap { max-width: 760px; margin: 0 auto; padding: 0 20px; }

/* ヘッダー：太線＋細線の二重罫 */
.nb-head { padding: 28px 0 0; }
.nb-head .nb-wrap { border-bottom: 4px solid var(--ink); padding-bottom: 14px; position: relative; }
.nb-head .nb-wrap::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -9px;
  border-bottom: 1px solid var(--ink);
}
.nb-head__name { margin: 0; font-family: var(--serif); font-size: 1.35rem; line-height: 1.5; font-weight: 700; }
.nb-head__name a { color: var(--ink); text-decoration: none; }
.nb-head__copy { margin: 4px 0 0; font-size: .85rem; color: var(--ink-soft); letter-spacing: .08em; }

.nb-main { padding-top: 40px; padding-bottom: 56px; }

.nb-label {
  font-family: var(--sans); font-size: .8rem; letter-spacing: .25em; font-weight: 700;
  margin: 0 0 16px; padding-bottom: 6px; border-bottom: 1px solid var(--ink);
}
.nb-no { color: var(--accent); font-weight: 700; letter-spacing: .1em; margin-right: 12px; }

/* 記事一覧：横長の帯 */
.nb-list { list-style: none; margin: 0; padding: 0; }
.nb-row { border-bottom: 1px dashed var(--ink-soft); }
.nb-row__link { display: flex; gap: 22px; padding: 22px 0; color: inherit; text-decoration: none; }
.nb-row__img {
  flex: 0 0 240px; width: 240px; aspect-ratio: 3 / 2; object-fit: cover;
  border: 1px solid var(--ink);
}
.nb-row__body { min-width: 0; }
.nb-row__meta { margin: 0; font-size: .8rem; color: var(--ink-soft); }
.nb-row__title { margin: 4px 0 8px; font-family: var(--serif); font-size: 1.15rem; line-height: 1.55; }
.nb-row__link:hover .nb-row__title { color: var(--accent); }
.nb-row__text { margin: 0; font-size: .875rem; color: var(--ink-soft); line-height: 1.75; }

/* パンくず */
.nb-crumb ol { list-style: none; margin: 0 0 24px; padding: 0; display: flex; flex-wrap: wrap; font-size: .78rem; color: var(--ink-soft); }
.nb-crumb li:not(:last-child)::after { content: "／"; margin: 0 6px; }
.nb-crumb a { color: var(--ink-soft); }

/* 記事 */
.nb-entry__title { font-family: var(--serif); font-size: 1.65rem; line-height: 1.5; margin: 6px 0 24px; }
.nb-entry__fig { margin: 0 auto 32px; max-width: 640px; }
.nb-entry__img { width: 100%; aspect-ratio: 3 / 2; object-fit: cover; border: 1px solid var(--ink); }

.nb-toc { background: var(--sand); border-top: 3px solid var(--ink); padding: 18px 24px 14px; margin: 0 0 40px; }
.nb-toc__label { margin: 0 0 6px; font-weight: 700; font-size: .85rem; letter-spacing: .2em; }
.nb-toc ol { margin: 0; padding-left: 1.6em; font-size: .92rem; line-height: 1.7; }
.nb-toc li { margin: 4px 0; }
.nb-toc li::marker { color: var(--accent); font-weight: 700; }
.nb-toc a { color: var(--ink); text-decoration: none; }
.nb-toc a:hover { color: var(--accent); text-decoration: underline; }

.nb-body h2 {
  font-family: var(--serif); font-size: 1.35rem; line-height: 1.55;
  margin: 56px 0 18px; padding: 4px 0 4px 14px; border-left: 5px solid var(--accent);
  scroll-margin-top: 16px;
}
.nb-body h3 {
  font-size: 1.05rem; margin: 32px 0 10px; padding-bottom: 4px;
  border-bottom: 1px dashed var(--ink-soft);
}
.nb-body p { margin: 0 0 1.3em; }
.nb-note { font-size: .85rem; color: var(--ink-soft); text-align: right; }

/* 関連記事 */
.nb-rel { margin-top: 64px; }
.nb-rel__list { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.nb-rel__item { display: block; color: var(--ink); text-decoration: none; }
.nb-rel__img { width: 100%; aspect-ratio: 3 / 2; object-fit: cover; border: 1px solid var(--ink); }
.nb-rel__title { display: block; margin-top: 8px; font-size: .85rem; line-height: 1.6; font-weight: 700; }
.nb-rel__item:hover .nb-rel__title { color: var(--accent); }

.nb-missing { padding: 40px 0; }

/* フッター */
.nb-foot { background: var(--ink); color: var(--paper); padding: 22px 0; font-size: .8rem; }
.nb-foot__row { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.nb-foot a { color: var(--paper); }

@media (max-width: 640px) {
  body { font-size: 15px; }
  .nb-head__name { font-size: 1.1rem; }
  .nb-row__link { flex-direction: column; gap: 12px; }
  .nb-row__img { flex: none; width: 100%; }
  .nb-entry__title { font-size: 1.35rem; }
  .nb-body h2 { font-size: 1.2rem; }
  .nb-toc { padding: 16px 16px 12px; }
  .nb-rel__list { grid-template-columns: 1fr; }
}