:root {
  color-scheme: dark;
  --ink-black: #0d1b2a;
  --prussian-blue: #1b263b;
  --dusk-blue: #415a77;
  --dusty-denim: #778da9;
  --alabaster-grey: #e0e1dd;

  --paper: var(--ink-black);
  --paper-raised: var(--alabaster-grey);
  --surface-soft: #16233a;
  --ink: var(--alabaster-grey);
  --ink-on-light: var(--ink-black);
  --ink-soft: var(--dusty-denim);
  --line: rgba(119, 141, 169, 0.22);
  --accent: var(--dusty-denim);
  --accent-strong: var(--dusk-blue);
  --ochre: var(--dusty-denim);

  --font-sans: "Hiragino Sans", "Yu Gothic", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--paper);
  background-image:
    radial-gradient(circle at 15% 0%, rgba(65, 90, 119, 0.35), transparent 45%),
    radial-gradient(circle at 85% 15%, rgba(27, 38, 59, 0.6), transparent 40%);
  color: var(--ink);
  font-family: var(--font-sans);
  line-height: 1.8;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; transition: color 0.2s ease; }
a:hover { color: var(--ink); text-decoration: underline; }
a:focus-visible, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.site-header {
  border-bottom: 1px solid var(--line);
  padding: 28px 24px 24px;
  backdrop-filter: blur(10px);
  background: rgba(13, 27, 42, 0.55);
}

.site-header .wrap {
  max-width: 720px;
  margin: 0 auto;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.site-title {
  font-weight: 800;
  font-size: 1.15rem;
  letter-spacing: 0.02em;
  margin: 0;
}

.site-title a { color: var(--ink); display: inline-flex; align-items: center; gap: 8px; }
.site-title a:hover { color: var(--ink); text-decoration: none; }

.site-title a::before {
  content: "く";
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  border-radius: 2px 8px 8px 8px;
  background: var(--alabaster-grey);
  color: var(--ink-black);
  font-size: 0.8rem;
  font-weight: 800;
}

.site-tagline {
  font-size: 0.85rem;
  color: var(--ink-soft);
  margin: 0;
}

main { max-width: 720px; margin: 0 auto; padding: 40px 24px 80px; }

.hero { margin-bottom: 48px; }

.hero p {
  font-size: 1.05rem;
  color: var(--ink-soft);
  max-width: 34em;
}

.category-heading {
  font-size: 1.4rem;
  letter-spacing: -0.01em;
  color: var(--alabaster-grey);
  font-weight: 800;
  margin: 56px 0 10px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--accent-strong);
}

.category-group:first-child .category-heading { margin-top: 0; }

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

.article-list li {
  border-top: 1px solid var(--line);
  padding: 24px 0;
}

.article-list li:last-child { border-bottom: 1px solid var(--line); }

.article-list .kicker,
.article-header .kicker {
  display: inline-block;
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 4px 14px;
  margin: 0 0 10px;
}

.article-list h2 {
  font-size: 1.2rem;
  margin: 0 0 8px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.article-list h2 a { color: var(--ink); }

.article-list .excerpt {
  color: var(--ink-soft);
  margin: 0;
  font-size: 0.95rem;
}

/* Article page */
.article-header { margin-bottom: 36px; }

.article-header h1 {
  font-size: 1.9rem;
  line-height: 1.45;
  letter-spacing: -0.02em;
  margin: 0 0 12px;
}

.article-meta {
  font-size: 0.82rem;
  color: var(--ink-soft);
}

.article-body h2 {
  font-size: 1.3rem;
  letter-spacing: -0.01em;
  margin: 2.2em 0 0.8em;
}

.article-body h3 {
  font-size: 1.05rem;
  margin: 1.8em 0 0.6em;
}

.article-body p { margin: 0 0 1.2em; }

.table-scroll {
  overflow-x: auto;
  margin: 1.5em 0;
  -webkit-overflow-scrolling: touch;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 0;
  font-size: 0.92rem;
}

.article-body th, .article-body td {
  border: 1px solid var(--line);
  padding: 10px 12px;
  text-align: left;
}

.article-body th { background: var(--surface-soft); font-weight: 600; }

.product-card {
  background: var(--paper-raised);
  color: var(--ink-on-light);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 20px 24px;
  margin: 1.5em 0;
}

.product-card h3 { margin-top: 0; color: var(--ink-on-light); }
.product-card p { color: var(--ink-on-light); }

.product-card img {
  display: block;
  width: 140px;
  height: 140px;
  object-fit: contain;
  background: #fff;
  border-radius: 10px;
  margin: 0 0 14px;
}

.cta-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 10px;
  padding: 10px 22px;
  background: var(--ink-black);
  color: var(--alabaster-grey);
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 700;
  transition: opacity 0.15s ease, transform 0.15s ease;
}

.cta-link:hover { opacity: 0.82; transform: translateY(-1px); text-decoration: none; }

.related-articles ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 10px;
}

.related-articles li {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 12px 18px;
}

.related-articles a { color: var(--ink); font-weight: 600; }

.disclosure-note {
  font-size: 0.82rem;
  color: var(--ink-on-light);
  border-left: 3px solid var(--dusk-blue);
  padding: 10px 16px;
  margin: 2em 0;
  background: var(--paper-raised);
  border-radius: 0 10px 10px 0;
}

.site-footer {
  border-top: 1px solid var(--line);
  padding: 32px 24px;
  text-align: center;
  font-size: 0.82rem;
  color: var(--ink-soft);
}

.site-footer nav { margin-bottom: 8px; }

.site-footer a { margin: 0 8px; }

@media (max-width: 480px) {
  .article-header h1 { font-size: 1.5rem; }
}