:root {
  --accent: #14b8a6;
  --accent-dark: #0f766e;
  --accent-deep: #115e59;
  --accent-light: #f0fdfa;
  --accent-mid: #99f6e4;
  --ink: #0f172a;
  --border: #e4e4e7;
  --text: #18181b;
  --muted: #71717a;
  --card-shadow: 0 1px 2px rgba(15, 23, 42, 0.05), 0 6px 24px rgba(15, 23, 42, 0.07);
}
* { box-sizing: border-box; }
body {
  font-family: "Hiragino Sans", "Yu Gothic UI", "Meiryo", sans-serif;
  color: var(--text);
  max-width: 760px;
  margin: 0 auto;
  padding: 0 16px 64px;
  line-height: 1.8;
  background: #fff;
}
a { color: var(--accent-dark); }

/* ---------- dark full-bleed header (matches LP hero) ---------- */
.site-header {
  width: 100vw;
  margin: 0 0 28px calc(50% - 50vw);
  padding: 14px max(16px, calc(50vw - 364px));
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  background:
    radial-gradient(ellipse 50% 90% at 15% 0%, rgba(20, 184, 166, 0.22), transparent 60%),
    linear-gradient(165deg, #0f172a 0%, #0e2a2e 60%, #114e4a 100%);
  border-bottom: 1px solid rgba(94, 234, 212, 0.25);
}
.site-header .logo {
  font-size: 1.08rem;
  font-weight: 700;
  text-decoration: none;
  color: #fff;
  display: inline-flex;
  align-items: center;
  gap: 9px;
  letter-spacing: 0.02em;
}
.brand-mark { width: 26px; height: 26px; border-radius: 7px; box-shadow: 0 2px 10px rgba(20, 184, 166, 0.45); }
.site-header nav { display: flex; gap: 8px; }
.site-header nav a {
  margin: 0;
  font-size: 0.86rem;
  text-decoration: none;
  color: rgba(255, 255, 255, 0.72);
  padding: 5px 13px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 999px;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
}
.site-header nav a:hover { color: #fff; border-color: rgba(94, 234, 212, 0.6); background: rgba(94, 234, 212, 0.08); }

.breadcrumb { font-size: 0.82rem; color: var(--muted); margin-bottom: 8px; }
.breadcrumb a { color: var(--muted); }

/* ---------- article ---------- */
article h1, body > h1 { font-size: 1.5rem; line-height: 1.5; margin: 0 0 8px; font-weight: 800; }
.article-meta { color: var(--muted); font-size: 0.82rem; margin-bottom: 26px; }
article h2 {
  font-size: 1.2rem;
  margin: 40px 0 14px;
  padding-left: 12px;
  border-left: 4px solid var(--accent);
  font-weight: 700;
}
article h3 { font-size: 1.02rem; margin: 20px 0 8px; }
article p { margin: 0 0 16px; }
article ol, article ul { margin: 0 0 16px; padding-left: 1.4em; }
article li { margin-bottom: 6px; }
article table {
  border-collapse: separate;
  border-spacing: 0;
  width: 100%;
  margin: 12px 0 20px;
  font-size: 0.88rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
  box-shadow: var(--card-shadow);
}
article th, article td { border-bottom: 1px solid var(--border); padding: 8px 12px; text-align: left; }
article tr:last-child td { border-bottom: none; }
article th {
  background: linear-gradient(135deg, var(--accent-dark), var(--accent-deep));
  color: #fff;
  border-bottom: none;
  font-weight: 700;
}
code, .formula {
  font-family: "SFMono-Regular", Menlo, monospace;
  background: var(--ink);
  color: #5eead4;
  border-radius: 6px;
  padding: 2px 8px;
  font-size: 0.86em;
}
.step-note {
  background: var(--accent-light);
  border: 1px solid rgba(20, 184, 166, 0.4);
  border-left: 4px solid var(--accent);
  border-radius: 8px;
  padding: 10px 14px;
  font-size: 0.88rem;
  margin: 0 0 16px;
}

/* ---------- CTA (dark, matches LP pricing card) ---------- */
.cta-box {
  background:
    radial-gradient(ellipse 80% 70% at 85% -10%, rgba(94, 234, 212, 0.35), transparent 60%),
    linear-gradient(160deg, #115e59 0%, #134e4a 65%, #0f3d3a 100%);
  border: 1px solid rgba(94, 234, 212, 0.4);
  border-radius: 14px;
  padding: 24px;
  margin: 32px 0;
  color: #fff;
  box-shadow: 0 10px 32px rgba(17, 94, 89, 0.3);
}
.cta-box h2 { border-left: none; padding-left: 0; margin-top: 0; color: #fff; }
.cta-box p { margin-bottom: 14px; color: rgba(240, 253, 250, 0.92); }
.cta-box a:not(.cta-button) { color: #99f6e4; }
.cta-button {
  display: inline-block;
  background: #fff;
  color: #115e59;
  text-decoration: none;
  padding: 11px 24px;
  border-radius: 9px;
  font-weight: 700;
  font-size: 0.95rem;
  box-shadow: 0 4px 14px rgba(2, 12, 27, 0.25);
  transition: transform 0.12s, box-shadow 0.12s;
}
.cta-button:hover { transform: translateY(-1px); box-shadow: 0 7px 20px rgba(2, 12, 27, 0.35); }

/* ---------- faq ---------- */
.faq dt { font-weight: 700; margin-top: 14px; }
.faq dd { margin: 4px 0 0; color: var(--muted); font-size: 0.92rem; }

/* ---------- article lists / related ---------- */
.blog-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 12px; }
.blog-list li {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 16px;
  background: #fff;
  box-shadow: var(--card-shadow);
  transition: border-color 0.15s, transform 0.15s, box-shadow 0.15s;
}
.blog-list li:hover {
  border-color: rgba(20, 184, 166, 0.5);
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(15, 23, 42, 0.1);
}
.blog-list a { text-decoration: none; font-weight: 600; font-size: 1.02rem; }
.blog-list p { margin: 6px 0 0; color: var(--muted); font-size: 0.88rem; }

/* ---------- index grid with thumbnails ---------- */
.blog-grid { grid-template-columns: repeat(2, 1fr); gap: 16px; }
@media (max-width: 620px) { .blog-grid { grid-template-columns: 1fr; } }
.blog-grid li { padding: 0 0 16px; overflow: hidden; }
.blog-grid .thumb { display: block; margin-bottom: 10px; background: #0f172a; }
.blog-grid .thumb img { display: block; width: 100%; height: auto; transition: transform 0.25s ease; }
.blog-grid li:hover .thumb img { transform: scale(1.04); }
.blog-grid li > a:not(.thumb) { display: block; padding: 0 16px; line-height: 1.55; }
.blog-grid p { padding: 0 16px; }

.related { margin-top: 44px; }
.related h2 {
  font-size: 1.1rem;
  border-left: 4px solid var(--accent);
  border-top: none;
  padding-left: 12px;
  padding-top: 0;
  margin: 0 0 14px;
}
.related .blog-list a { font-size: 0.95rem; }

/* ---------- dark full-bleed footer (matches LP) ---------- */
footer.site-footer {
  width: 100vw;
  margin: 56px 0 -64px calc(50% - 50vw);
  padding: 30px max(16px, calc(50vw - 364px)) 44px;
  background: linear-gradient(180deg, #0f172a 0%, #0b1220 100%);
  color: #94a3b8;
  font-size: 0.78rem;
  border-top: none;
}
footer.site-footer a { color: #5eead4; }