:root {
  --color-bg: #f6f7f9;
  --color-surface: #ffffff;
  --color-text: #1f2733;
  --color-text-muted: #5b6675;
  --color-primary: #2c5282;
  --color-primary-dark: #1e3a5f;
  --color-accent: #c53030;
  --color-border: #e2e6ec;
  --color-chip: #edf2f7;
  --shadow-card: 0 1px 3px rgba(20, 30, 50, 0.08), 0 1px 2px rgba(20, 30, 50, 0.04);
  --shadow-card-hover: 0 6px 16px rgba(20, 30, 50, 0.12);
  --radius: 12px;
  --font-body: 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', 'Yu Gothic UI', 'Meiryo',
    system-ui, -apple-system, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.85;
  overflow-wrap: anywhere;
}

a {
  color: var(--color-primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
}

/* ---------- レイアウト ---------- */

.site-header {
  background: linear-gradient(135deg, var(--color-primary-dark), var(--color-primary));
  color: #fff;
  padding: 0.9rem 1rem;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: 0 2px 8px rgba(20, 30, 50, 0.25);
}

.site-header__inner {
  max-width: 1180px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.site-header__title {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.site-header__title a {
  color: #fff;
  text-decoration: none;
}

.site-header__tagline {
  font-size: 0.75rem;
  opacity: 0.85;
  margin: 0;
}

.site-nav {
  margin-left: auto;
  display: flex;
  gap: 0.25rem;
  flex-wrap: wrap;
}

.site-nav a {
  color: #fff;
  font-size: 0.85rem;
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  text-decoration: none;
  transition: background 0.15s;
}

.site-nav a:hover {
  background: rgba(255, 255, 255, 0.15);
}

.layout {
  max-width: 1180px;
  margin: 0 auto;
  padding: 1.5rem 1rem 3rem;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 2rem;
  align-items: start;
}

@media (max-width: 960px) {
  .layout {
    grid-template-columns: minmax(0, 1fr);
  }
}

.site-footer {
  background: var(--color-primary-dark);
  color: #cbd7e6;
  padding: 2rem 1rem;
  font-size: 0.85rem;
}

.site-footer__inner {
  max-width: 1180px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: space-between;
  align-items: center;
}

.site-footer a {
  color: #e6eef8;
}

/* ---------- サイドバー ---------- */

.sidebar {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.widget {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1rem 1.1rem;
  box-shadow: var(--shadow-card);
}

.widget__title {
  margin: 0 0 0.7rem;
  font-size: 0.95rem;
  font-weight: 700;
  padding-bottom: 0.45rem;
  border-bottom: 2px solid var(--color-primary);
}

.widget ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.widget-recent li {
  padding: 0.45rem 0;
  border-bottom: 1px dashed var(--color-border);
  font-size: 0.85rem;
  line-height: 1.5;
}

.widget-recent li:last-child {
  border-bottom: none;
}

.widget-recent__date {
  display: block;
  color: var(--color-text-muted);
  font-size: 0.72rem;
  margin-top: 0.15rem;
}

.widget-list li {
  padding: 0.3rem 0;
  font-size: 0.85rem;
}

.widget-list a {
  display: flex;
  justify-content: space-between;
  gap: 0.5rem;
}

.widget-list .count {
  color: var(--color-text-muted);
  font-size: 0.78rem;
}

.moshimo-disclosure {
  font-size: 0.72rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

/* ---------- カード一覧（トップ） ---------- */

.page-title {
  margin: 0 0 0.4rem;
  font-size: 1.5rem;
  line-height: 1.4;
}

.page-lead {
  color: var(--color-text-muted);
  font-size: 0.92rem;
  margin: 0 0 1.4rem;
}

.column-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.column-card {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  transition: box-shadow 0.15s, transform 0.15s;
}

.column-card:hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
}

@media (max-width: 640px) {
  .column-card {
    grid-template-columns: minmax(0, 1fr);
  }
}

.column-card__thumb {
  display: block;
  background: var(--color-chip);
  min-height: 150px;
}

.column-card__thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.column-card__placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  min-height: 150px;
  font-size: 3rem;
}

.column-card__body {
  padding: 0.9rem 1.1rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.column-card__cat {
  align-self: flex-start;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--color-primary);
  background: var(--color-chip);
  padding: 0.15rem 0.6rem;
  border-radius: 999px;
}

.column-card__title {
  margin: 0;
  font-size: 1.05rem;
  line-height: 1.5;
}

.column-card__title a {
  color: var(--color-text);
}

.column-card__excerpt {
  margin: 0;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.column-card__meta {
  margin-top: auto;
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

/* ページャー */

.pager {
  display: flex;
  gap: 0.4rem;
  justify-content: center;
  margin: 2rem 0 0;
  flex-wrap: wrap;
}

.pager a,
.pager span {
  min-width: 2.3rem;
  padding: 0.4rem 0.7rem;
  text-align: center;
  border-radius: 8px;
  font-size: 0.9rem;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
}

.pager .current {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
  font-weight: 700;
}

/* ---------- 教科書トップ・カテゴリ ---------- */

.help-numbers {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.6rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.help-numbers li {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-accent);
  border-radius: 8px;
  padding: 0.55rem 0.8rem;
  font-size: 0.85rem;
  line-height: 1.5;
}

.help-numbers .num {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--color-accent);
  margin-right: 0.5rem;
}

.section-title {
  font-size: 1.15rem;
  margin: 2rem 0 0.9rem;
  padding-left: 0.7rem;
  border-left: 4px solid var(--color-primary);
}

.cat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1rem;
}

.cat-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  transition: box-shadow 0.15s, transform 0.15s;
  display: flex;
  flex-direction: column;
}

.cat-card:hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
}

.cat-card__thumb {
  display: block;
  aspect-ratio: 16 / 9;
  background: var(--color-chip);
  overflow: hidden;
}

.cat-card__thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.cat-card__placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  font-size: 3rem;
}

.cat-card__body {
  padding: 0.8rem 1rem 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  flex: 1;
}

.cat-card__title {
  margin: 0;
  font-size: 1rem;
  line-height: 1.5;
}

.cat-card__title a {
  color: var(--color-text);
}

.cat-card__desc {
  margin: 0;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

.cat-card__count {
  margin-top: auto;
  font-size: 0.78rem;
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.chips a {
  font-size: 0.75rem;
  background: var(--color-chip);
  color: var(--color-primary-dark);
  padding: 0.15rem 0.65rem;
  border-radius: 999px;
}

.chips a span {
  color: var(--color-text-muted);
  margin-left: 0.3em;
  font-size: 0.7rem;
}

.help-links {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1rem 1.2rem;
  margin: 1.2rem 0;
}

.help-links h2 {
  margin: 0 0 0.6rem;
  font-size: 1rem;
}

.help-links ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.4rem;
}

.help-links li {
  font-size: 0.85rem;
  line-height: 1.6;
}

.help-links li span {
  color: var(--color-text-muted);
  margin-left: 0.6em;
  font-size: 0.8rem;
}

.breadcrumb {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-bottom: 1rem;
}

.breadcrumb ol {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
}

.breadcrumb li + li::before {
  content: '›';
  margin-right: 0.3rem;
  color: var(--color-text-muted);
}

/* ---------- 記事本文 ---------- */

.article {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.6rem 1.8rem 2rem;
  box-shadow: var(--shadow-card);
}

@media (max-width: 640px) {
  .article {
    padding: 1.2rem 1rem 1.5rem;
  }
}

.article__header {
  margin-bottom: 1.2rem;
}

.article__title {
  margin: 0.3rem 0 0.5rem;
  font-size: 1.55rem;
  line-height: 1.45;
}

.article__meta {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  display: flex;
  gap: 0.8rem;
  align-items: center;
  flex-wrap: wrap;
}

.article__meta .cat {
  background: var(--color-chip);
  color: var(--color-primary);
  font-weight: 700;
  padding: 0.1rem 0.6rem;
  border-radius: 999px;
}

.article-body {
  font-size: 0.98rem;
}

.article-body h2 {
  font-size: 1.25rem;
  margin: 2.2rem 0 1rem;
  padding: 0.5rem 0.9rem;
  background: linear-gradient(90deg, var(--color-chip), transparent);
  border-left: 4px solid var(--color-primary);
  border-radius: 4px;
  line-height: 1.5;
}

.article-body h3 {
  font-size: 1.05rem;
  margin: 1.8rem 0 0.8rem;
  padding-bottom: 0.3rem;
  border-bottom: 2px solid var(--color-border);
}

.article-body ul {
  padding-left: 1.4rem;
}

.article-body li {
  margin: 0.45rem 0;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.88rem;
}

.article-body th,
.article-body td {
  border: 1px solid var(--color-border);
  padding: 0.55rem 0.75rem;
  text-align: left;
  vertical-align: top;
  line-height: 1.6;
}

.article-body th {
  background: var(--color-chip);
  white-space: nowrap;
}

.article-body blockquote {
  margin: 1.2rem 0;
  padding: 0.8rem 1.1rem;
  background: #fdf6ec;
  border-left: 4px solid #d69e2e;
  border-radius: 4px;
  font-size: 0.85rem;
  color: #5f4b1e;
}

.article-body blockquote p {
  margin: 0;
}

.article-body hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 1.8rem 0;
}

.article-image {
  margin: 1.2rem 0;
  text-align: center;
}

.article-image img {
  border-radius: 10px;
  box-shadow: var(--shadow-card);
}

.article-image--small img {
  max-width: 400px;
  width: 100%;
}

/* ---------- アフィリエイト ---------- */

.moshimo-affiliate {
  margin: 1.6rem 0;
  padding: 1rem 1.2rem;
  border: 1px dashed var(--color-border);
  border-radius: var(--radius);
  background: #fbfcfe;
}

.moshimo-affiliate__label {
  font-size: 0.7rem;
  color: var(--color-text-muted);
  margin-bottom: 0.4rem;
}

.moshimo-affiliate__body {
  max-width: 160px;
}

.moshimo-affiliate__body img {
  max-width: 100% !important;
  width: auto !important;
  height: auto !important;
  display: block;
}

.moshimo-affiliate__body img[width="0"] {
  width: 0 !important;
  max-width: none !important;
  height: 1px !important;
}

.valuecommerce-sidebar-ad {
  text-align: center;
}

/* ---------- 記事ナビ ---------- */

.article-nav {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 1.6rem;
  font-size: 0.88rem;
  flex-wrap: wrap;
}

/* ---------- 検索 (Pagefind) ---------- */

.search-box {
  --pagefind-ui-primary: var(--color-primary);
  --pagefind-ui-text: var(--color-text);
  --pagefind-ui-background: var(--color-surface);
  --pagefind-ui-border: var(--color-border);
  --pagefind-ui-border-width: 1px;
  --pagefind-ui-border-radius: 8px;
  --pagefind-ui-font: var(--font-body);
  --pagefind-ui-scale: 0.85;
}

/* ---------- アーカイブ ---------- */

.archive-title {
  font-size: 1.3rem;
  margin: 0 0 1.2rem;
}

/* 関連ニュース */
.related-news {
  margin: 2rem 0 0;
}

.related-news__list {
  display: grid;
  gap: 0.75rem;
  padding: 0;
  margin: 1rem 0 0;
  list-style: none;
}

.related-news__item {
  margin: 0;
}

.related-news__item[hidden] {
  display: none;
}

.related-news__item a {
  position: relative;
  display: block;
  padding: 0.9rem 2.6rem 0.9rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-surface);
  box-shadow: var(--shadow-card);
  color: var(--color-text);
  font-weight: 700;
  line-height: 1.65;
  text-decoration: none;
}

.related-news__item a::after {
  content: '›';
  position: absolute;
  top: 50%;
  right: 1rem;
  transform: translateY(-50%);
  color: var(--color-primary);
  font-size: 1.35rem;
  line-height: 1;
}

.related-news__item a:hover,
.related-news__item a:focus-visible {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-card-hover);
  color: var(--color-primary);
  outline: none;
  text-decoration: none;
}

.related-news__pager {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin: 1rem 0 0;
}

.related-news__pager button {
  min-width: 2.4rem;
  min-height: 2.4rem;
  padding: 0.35rem 0.65rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-surface);
  color: var(--color-primary);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

.related-news__pager button:hover,
.related-news__pager button:focus-visible {
  border-color: var(--color-primary);
  outline: none;
}

.related-news__pager button.current {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}