/* ============================================================
   サイトA: まなび百科 — 学習メディアデザイン v2 (Claude design)
   コンセプト: 清潔・知的・親しみ。教科書のように読みやすく、
   ツールと表がストレスなく使えること。
   ============================================================ */
:root {
  --primary: #1d4ed8;
  --primary-strong: #1e40af;
  --primary-soft: #eff6ff;
  --primary-border: #bfdbfe;
  --accent: #059669;
  --accent-soft: #ecfdf5;
  --ink: #1e293b;
  --ink-sub: #64748b;
  --ink-faint: #94a3b8;
  --bg: #ffffff;
  --bg-soft: #f8fafc;
  --border: #e2e8f0;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, .06);
  --shadow-md: 0 4px 16px rgba(15, 23, 42, .08);
  --font: "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Yu Gothic Medium", "Yu Gothic", Meiryo, system-ui, sans-serif;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  color: var(--ink); background: var(--bg);
  line-height: 1.9; font-size: 16px;
  -webkit-font-smoothing: antialiased;
}
.container { max-width: 880px; margin: 0 auto; padding: 0 20px; }
a { color: var(--primary); }
a:hover { opacity: .85; }
:focus-visible { outline: 3px solid var(--primary-border); outline-offset: 2px; }

/* ---------- header ---------- */
.site-header {
  background: #fff;
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 50;
  box-shadow: var(--shadow-sm);
}
.site-header .container {
  display: flex; flex-wrap: wrap; align-items: center;
  gap: 6px 24px; padding: 14px 20px;
}
.logo {
  color: var(--primary-strong); font-size: 1.35rem; font-weight: 800;
  text-decoration: none; letter-spacing: .02em;
}
.logo::before { content: "📖 "; }
.global-nav { display: flex; flex-wrap: wrap; gap: 2px; margin-left: auto; }
.global-nav a {
  color: var(--ink-sub); text-decoration: none; font-size: .85rem; font-weight: 600;
  padding: 6px 10px; border-radius: 999px;
  transition: background .15s, color .15s;
}
.global-nav a:hover { background: var(--primary-soft); color: var(--primary-strong); opacity: 1; }

/* ---------- hero ---------- */
.hero {
  background: linear-gradient(135deg, var(--primary-soft) 0%, #f0fdfa 100%);
  border: 1px solid var(--primary-border);
  border-radius: var(--radius);
  padding: 48px 32px; margin: 28px 0;
}
.hero h1 { font-size: 1.9rem; margin-bottom: 10px; color: var(--primary-strong); letter-spacing: .01em; }
.hero p { color: var(--ink-sub); max-width: 40em; }

/* ---------- sections / cards ---------- */
.cat-section { margin: 40px 0; }
.cat-section h2 {
  display: flex; align-items: center; gap: 10px;
  font-size: 1.3rem; margin-bottom: 16px;
}
.cat-section h2::before {
  content: ""; width: 6px; height: 1.2em; border-radius: 3px;
  background: linear-gradient(180deg, var(--primary), var(--accent));
}
.cat-section h2 a { color: var(--ink); text-decoration: none; }
.cat-section h2 a:hover { color: var(--primary); }

.card-list {
  list-style: none;
  display: grid; grid-template-columns: repeat(auto-fill, minmax(255px, 1fr)); gap: 12px;
}
.card-list li a {
  display: block; height: 100%;
  padding: 16px 18px;
  border: 1px solid var(--border); border-radius: var(--radius);
  background: #fff; color: var(--ink); text-decoration: none;
  font-weight: 600; font-size: .95rem; line-height: 1.6;
  box-shadow: var(--shadow-sm);
  transition: transform .15s, box-shadow .15s, border-color .15s;
}
.card-list li a:hover {
  transform: translateY(-2px);
  border-color: var(--primary-border);
  box-shadow: var(--shadow-md);
  opacity: 1;
}
.card-cat { display: block; font-size: .74rem; color: var(--primary); font-weight: 700; margin-bottom: 2px; letter-spacing: .04em; }
.card-desc { display: block; font-size: .82rem; color: var(--ink-sub); margin-top: 6px; font-weight: 400; }
.card-list-lg { grid-template-columns: 1fr; }

/* ---------- breadcrumb ---------- */
.breadcrumb { font-size: .8rem; color: var(--ink-faint); margin: 16px 0; }
.breadcrumb a { color: var(--ink-faint); text-decoration: none; }
.breadcrumb a:hover { color: var(--primary); }

/* ---------- article ---------- */
.post-header { margin: 8px 0 24px; }
.post-category {
  display: inline-block; color: var(--primary-strong); background: var(--primary-soft);
  font-weight: 700; font-size: .78rem; padding: 3px 12px; border-radius: 999px;
}
.post h1 { font-size: 1.75rem; line-height: 1.45; margin: 12px 0 8px; letter-spacing: .01em; }
.post-date { color: var(--ink-faint); font-size: .82rem; }

.toc-box {
  background: var(--bg-soft); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px 24px; margin: 24px 0;
}
.toc-title { font-weight: 800; margin-bottom: 8px; font-size: .95rem; }
.toc-title::before { content: "☰ "; color: var(--primary); }
.toc-box ul { padding-left: 20px; font-size: .9rem; line-height: 2; }
.toc-box a { text-decoration: none; }
.toc-box a:hover { text-decoration: underline; }

.post-body { font-size: 1.02rem; }
.post-body h2 {
  font-size: 1.4rem; line-height: 1.5;
  margin: 48px 0 18px; padding: 10px 16px;
  background: var(--primary-soft);
  border-left: 6px solid var(--primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.post-body h3 {
  font-size: 1.15rem; margin: 32px 0 14px; padding-bottom: 6px;
  border-bottom: 2px solid var(--primary-border);
}
.post-body p { margin: 16px 0; }
.post-body ul, .post-body ol { margin: 16px 0 16px 26px; }
.post-body li { margin: 6px 0; }
.post-body table {
  border-collapse: collapse; width: 100%; margin: 20px 0;
  font-size: .92rem; display: block; overflow-x: auto;
  border-radius: var(--radius-sm);
}
.post-body th, .post-body td { border: 1px solid var(--border); padding: 10px 14px; text-align: left; }
.post-body th { background: var(--primary-soft); color: var(--primary-strong); font-weight: 700; white-space: nowrap; }
.post-body tr:nth-child(even) td { background: var(--bg-soft); }
.post-body blockquote {
  border-left: 4px solid var(--accent); background: var(--accent-soft);
  padding: 14px 18px; margin: 18px 0; border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.post-body code {
  background: var(--bg-soft); border: 1px solid var(--border);
  padding: 2px 6px; border-radius: 5px; font-size: .9em;
}
.post-body .point-box, .post-body .formula-box {
  border: 2px solid var(--primary); border-radius: var(--radius);
  padding: 18px 22px; margin: 24px 0;
  background: var(--primary-soft);
  box-shadow: var(--shadow-sm);
}
.post-body .point-box::before {
  content: "POINT"; display: block;
  color: var(--primary-strong); font-weight: 800; font-size: .78rem;
  letter-spacing: .12em; margin-bottom: 6px;
}
.post-body .formula-box { text-align: center; font-size: 1.15rem; font-weight: 700; }

/* ---------- tools ---------- */
.tool-box {
  border: 2px solid var(--accent); border-radius: var(--radius);
  padding: 24px; margin: 24px 0; background: var(--accent-soft);
  box-shadow: var(--shadow-sm);
}
.tool-box label { display: block; font-weight: 700; margin: 14px 0 6px; font-size: .92rem; }
.tool-box input, .tool-box select {
  width: 100%; max-width: 340px; padding: 12px 14px; font-size: 1.05rem;
  border: 1.5px solid var(--border); border-radius: var(--radius-sm);
  background: #fff;
}
.tool-box input:focus { border-color: var(--accent); outline: none; }
.tool-box button {
  margin-top: 18px; padding: 13px 34px; font-size: 1rem; font-weight: 800;
  color: #fff; background: var(--accent);
  border: none; border-radius: 999px; cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: transform .15s, box-shadow .15s;
}
.tool-box button:hover { transform: translateY(-1px); box-shadow: var(--shadow-md); }
.tool-result { font-size: 1.35rem; font-weight: 800; margin-top: 16px; color: var(--primary-strong); }

/* ---------- related ---------- */
.related { margin: 48px 0; padding-top: 24px; border-top: 1px solid var(--border); }
.related h2 { font-size: 1.2rem; margin-bottom: 14px; }

/* ---------- footer ---------- */
.site-footer {
  background: #0f172a; color: #cbd5e1;
  margin-top: 64px; padding: 36px 0 28px; font-size: .85rem;
}
.site-footer nav { display: flex; flex-wrap: wrap; gap: 8px 18px; margin-bottom: 12px; }
.site-footer a { color: #cbd5e1; text-decoration: none; }
.site-footer a:hover { color: #fff; opacity: 1; }
.footer-sub { padding-top: 10px; border-top: 1px solid #1e293b; }
.copyright { margin-top: 14px; color: #64748b; }

/* ---------- responsive ---------- */
@media (max-width: 640px) {
  body { font-size: 15.5px; }
  .post h1 { font-size: 1.4rem; }
  .hero { padding: 32px 22px; }
  .hero h1 { font-size: 1.45rem; }
  .post-body h2 { font-size: 1.22rem; margin-top: 40px; }
  .global-nav { margin-left: 0; }
}