/* ── Design tokens & reset ──────────────────────────────────── */

:root {
  --color-accent:       #315f9d;
  --color-accent-dark:  #12365f;
  --color-bg:           #f6f9fc;
  --color-bg-secondary: #eef4fb;
  --color-bg-white:     #ffffff;
  --color-text:         #263a55;
  --color-text-sub:     #52647a;
  --color-text-muted:   #7c8da1;
  --color-border:       #dce3ec;
  --color-border-light: #edf1f5;
  --color-brand-dark:   #102b50;
  --color-success:      #16a34a;
  --color-warning:      #d97706;
  --color-error:        #dc2626;
  --font-body:    'LINE Seed JP', 'Hiragino Sans', 'Yu Gothic', sans-serif;
  --font-heading: 'LINE Seed JP', 'Hiragino Sans', sans-serif;
  --font-mono:    'SFMono-Regular', 'Consolas', 'Menlo', monospace;
  --transition:   0.3s cubic-bezier(0.4, 0.4, 0, 1);
}

*, *::before, *::after { box-sizing: border-box; }
[hidden] { display: none !important; }

body {
  margin: 0;
  padding: 0;
  background: var(--color-bg-white);
  font-family: var(--font-body);
  font-size: 1rem;
  color: var(--color-text);
  line-height: 1.7;
  letter-spacing: 0;
  overflow-wrap: break-word;
  line-break: strict;
}

/* ── Article layout ─────────────────────────────────────────── */
.article-page-main {
  min-height: 52vh;
  background: #fff;
}

.article-container {
  width: min(var(--article-width, 720px), calc(100% - var(--viewport-gutter, 64px)));
  margin: 0 auto;
  padding: 3.5rem 0 5rem;
}

.article-container--list {
  width: min(var(--article-list-width, 960px), calc(100% - var(--viewport-gutter, 64px)));
}

.article-page-main.page-content .article-container {
  padding: 0;
}

/* ── Article header ─────────────────────────────────────────── */
.article-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
}
.article-title {
  font-family: var(--font-heading);
  font-size: 1.8125rem;
  font-weight: 700;
  line-height: 1.4;
  letter-spacing: 0;
  color: var(--color-brand-dark);
  margin: 0 0 0.75rem;
  word-break: auto-phrase;
}
.article-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.8125rem;
  color: var(--color-text-sub);
}
.article-meta time { font-variant-numeric: tabular-nums; }
.article-reading-time-sep { color: var(--color-text-muted); }
.article-tags { display: flex; flex-wrap: wrap; gap: 0.35rem; margin-left: auto; }
.article-tag {
  display: inline-block;
  padding: 0.15rem 0.6rem;
  background: var(--color-bg-secondary);
  border-radius: 50px;
  font-size: 0.75rem;
  color: var(--color-text-sub);
  text-decoration: none;
}
.article-tag--cat {
  background: color-mix(in srgb, var(--color-accent) 10%, transparent);
  color: var(--color-accent);
  font-weight: 700;
  transition: background 0.2s;
}
.article-tag--cat:hover {
  background: color-mix(in srgb, var(--color-accent) 20%, transparent);
}

.article-detail-hero .article-title {
  font-size: clamp(1.8125rem, 3.2vw, 2.5rem);
  word-break: auto-phrase;
}

.article-detail-hero .article-meta {
  justify-content: center;
}

.article-detail-hero .article-tags {
  justify-content: center;
  margin-left: 0;
}

.article-detail-hero .md-link {
  margin-left: 0;
}

/* ── Table of contents ──────────────────────────────────────── */
.toc {
  background: var(--color-bg-secondary);
  border-left: 3px solid var(--color-accent);
  border-radius: 0 8px 8px 0;
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  font-size: 0.875rem;
}
.toc-title {
  font-weight: 700;
  margin: 0 0 0.5rem;
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-sub);
}
.toc ol, .toc ul { margin: 0; padding-left: 1.25rem; }
.toc li { margin: 0.25rem 0; }
.toc a { color: var(--color-text); text-decoration: none; }
.toc a:hover { color: var(--color-accent); }
.toc .toc-h3 { font-size: 0.8125rem; color: var(--color-text-sub); margin-left: 1.25em; }

/* ── Article body ───────────────────────────────────────────── */
.article-body {
  line-height: 1.85;
  letter-spacing: 0;
  overflow-wrap: anywhere;
  word-break: break-word;
}
.article-body h2 {
  font-size: 1.1875rem;
  font-weight: 700;
  margin: 2.25rem 0 0.75rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--color-border-light);
  color: var(--color-brand-dark);
}
.article-body h3 {
  font-size: 1.0625rem;
  font-weight: 700;
  margin: 1.75rem 0 0.5rem;
  color: var(--color-brand-dark);
}
.article-body h4 {
  font-size: 1rem;
  font-weight: 700;
  margin: 1.5rem 0 0.4rem;
}
.article-body p    { margin: 0 0 1rem; }
.article-body ul, .article-body ol { margin: 0 0 1rem; padding-left: 1.5rem; }
.article-body li   { margin: 0.3rem 0; }
.article-body li ul, .article-body li ol { margin-bottom: 0; }
.article-body blockquote {
  margin: 1rem 0;
  padding: 0.75rem 1rem;
  border-left: 3px solid var(--color-accent);
  background: var(--color-bg-secondary);
  border-radius: 0 8px 8px 0;
  color: var(--color-text-sub);
  font-style: italic;
}
.article-body hr { border: none; border-top: 1px solid var(--color-border); margin: 2rem 0; }
.article-body img { max-width: 100%; height: auto; border-radius: 8px; margin: 0.5rem 0; }
.article-body a { color: var(--color-accent); }
.article-body a:hover { text-decoration: underline; }
.article-body strong { font-weight: 700; color: var(--color-brand-dark); }

/* ── Code ───────────────────────────────────────────────────── */
.article-body code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--color-bg-secondary);
  padding: 0.1em 0.4em;
  border-radius: 4px;
  border: 1px solid var(--color-border-light);
}
.article-body pre {
  background: #0f172a;
  border-radius: 10px;
  padding: 1.1rem 1.25rem;
  overflow-x: auto;
  margin: 1rem 0;
  line-height: 1.6;
}
.article-body pre code {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  background: none;
  border: none;
  padding: 0;
  color: #e2e8f0;
}

/* ── Table ──────────────────────────────────────────────────── */
.article-body .table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; margin: 1rem 0; }
.article-body table { width: 100%; border-collapse: collapse; font-size: 0.875rem; }
.article-body th {
  background: var(--color-bg-secondary);
  font-weight: 700;
  text-align: left;
  padding: 0.55rem 0.75rem;
  border: 1px solid var(--color-border);
}
.article-body td { padding: 0.5rem 0.75rem; border: 1px solid var(--color-border-light); vertical-align: top; }

/* ── Related links ──────────────────────────────────────────── */
.related-tools {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
}
.related-tools-title {
  font-size: 0.8125rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-sub);
  margin: 0 0 0.75rem;
}
.related-tools-list { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.related-tool-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.4rem 0.9rem;
  background: var(--color-bg-white);
  border: 1px solid var(--color-border);
  border-radius: 50px;
  font-size: 0.8125rem;
  color: var(--color-text);
  text-decoration: none;
  transition: all var(--transition);
}
.related-tool-link:hover { border-color: var(--color-accent); color: var(--color-accent); }

/* ── .md source link ────────────────────────────────────────── */
.md-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.8rem;
  color: var(--color-text-sub);
  text-decoration: none;
  letter-spacing: 0.04em;
  transition: color var(--transition);
  margin-left: auto;
}
.md-link:hover { color: var(--color-accent); }
.md-link .bi { font-size: 14px; flex-shrink: 0; }

/* ── Prev/next nav ──────────────────────────────────────────── */
.article-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
}
.article-nav a {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 0.75rem 1rem;
  background: var(--color-bg-white);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  text-decoration: none;
  transition: border-color var(--transition);
}
.article-nav a:hover { border-color: var(--color-accent); }
.article-nav-label { font-size: 0.75rem; color: var(--color-text-muted); }
.article-nav-title { font-size: 0.875rem; color: var(--color-text); font-weight: 400; }
.article-nav .next { text-align: right; }
.article-nav .prev:empty, .article-nav .next:empty { visibility: hidden; }

/* ── Article list ───────────────────────────────────────────── */
.article-list { display: flex; flex-direction: column; gap: 1rem; }
.article-card {
  display: block;
  padding: 1.25rem 1.5rem;
  background: var(--color-bg-white);
  border: 1px solid var(--color-border-light);
  border-radius: 8px;
  text-decoration: none;
  box-shadow: 0 10px 24px rgba(16, 43, 80, 0.06);
  transition: border-color var(--transition);
}
.article-card:hover { border-color: var(--color-accent); }
.article-card-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
  margin: 0 0 0.35rem;
  line-height: 1.5;
}
.article-card-desc {
  font-size: 0.9375rem;
  color: var(--color-text-sub);
  margin: 0 0 0.5rem;
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.article-card-meta {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

/* ── Category filter ────────────────────────────────────────── */
.tag-filter { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 1.25rem; }
.tag-filter-item {
  display: inline-block;
  padding: 0.3rem 0.9rem;
  border: 1px solid var(--color-border);
  border-radius: 50px;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--color-text-sub);
  text-decoration: none;
  background: var(--color-bg-white);
  min-height: 32px;
  line-height: 1.6;
  transition: border-color 0.2s, color 0.2s, background 0.2s;
}
.tag-filter-item:not(.is-active):hover { border-color: var(--color-accent); color: var(--color-accent); }
.tag-filter-item.is-active { background: var(--color-accent); border-color: var(--color-accent); color: #fff; }
.tag-filter-note { font-size: 0.875rem; color: var(--color-text-sub); margin: 0 0 1rem; }
.tag-filter-note a { color: var(--color-accent); text-decoration: none; }
.tag-filter-note a:hover { text-decoration: underline; }

/* ── Pagination ─────────────────────────────────────────────── */
.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-top: 2.5rem;
  padding: 2.75rem 0 2rem;
  border-top: 1px solid var(--color-border-light);
  border-bottom: 1px solid var(--color-border-light);
  flex-wrap: nowrap;
}
.pagination-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 56px;
  width: 56px;
  height: 56px;
  padding: 0;
  border: 2px solid var(--color-border);
  border-radius: 16px;
  background: var(--color-bg-white);
  color: var(--color-text);
  text-decoration: none;
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s, background 0.2s;
}
.pagination-button .bi { font-size: 22px; }
.pagination-button:hover {
  border-color: var(--color-text-sub);
}
.pagination-button.is-disabled {
  color: var(--color-text-muted);
  background: var(--color-bg-secondary);
  cursor: not-allowed;
  opacity: 0.5;
}
.pagination-form {
  flex: 0 0 176px;
  width: 176px;
  margin: 0;
}
.pagination-select-wrap {
  position: relative;
  display: block;
  width: 100%;
}
.pagination-select-wrap::after {
  content: '';
  position: absolute;
  top: 50%;
  right: 26px;
  width: 10px;
  height: 10px;
  border-right: 3px solid var(--color-text-sub);
  border-bottom: 3px solid var(--color-text-sub);
  transform: translateY(-70%) rotate(45deg);
  pointer-events: none;
}
.pagination-select {
  appearance: none;
  width: 100%;
  height: 56px;
  padding: 0 52px 0 20px;
  border: 2px solid var(--color-border);
  border-radius: 16px;
  background: var(--color-bg-white);
  color: var(--color-text);
  font: inherit;
  font-size: 1.75rem;
  font-variant-numeric: tabular-nums;
  line-height: 1;
  cursor: pointer;
}
.pagination-button:focus-visible,
.pagination-select:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--color-accent) 35%, transparent);
  outline-offset: 3px;
}
.pagination-submit {
  margin-left: 0.5rem;
}
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

.article-list-heading {
  margin: 0 0 1.4rem;
  color: var(--color-brand-dark);
  font-size: clamp(1.75rem, 3vw, 2.35rem);
  line-height: 1.4;
}

.article-empty {
  padding: 3rem 1.5rem;
  color: var(--color-text-sub);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  text-align: center;
}

.article-empty > .bi {
  color: var(--color-accent);
  font-size: 42px;
}

.article-empty p {
  margin: 0.8rem 0 1.3rem;
}

.article-error-main {
  display: grid;
  min-height: 55vh;
  place-items: center;
}

.article-error-panel {
  text-align: center;
}

.article-error-panel h1 {
  margin: 1rem 0 0.5rem;
  color: var(--color-brand-dark);
  font-size: 1.8rem;
}

.article-error-panel > p:not(.error-code) {
  margin: 0 0 1.5rem;
  color: var(--color-text-sub);
}

/* ── Responsive ─────────────────────────────────────────────── */
@media (max-width: 600px) {
  .article-container { padding: 1.5rem 0 3.5rem; }
  .article-title { font-size: 1.375rem; }
  .article-tags { margin-left: 0; }
  .article-nav { grid-template-columns: 1fr; }
  .article-nav .next { text-align: left; }
  .pagination { gap: 0.5rem; padding: 2rem 0 1.5rem; }
  .pagination-button { flex-basis: 48px; width: 48px; height: 48px; border-radius: 14px; }
  .pagination-form { flex: 0 1 160px; width: min(160px, calc(100vw - 9rem)); }
  .pagination-select { height: 48px; padding: 0 44px 0 16px; border-radius: 14px; font-size: 1.25rem; }
  .pagination-select-wrap::after { right: 21px; width: 9px; height: 9px; }
}