*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  font-size: 18px;
  line-height: 1.75;
  color: #1a1a1a;
  background: #fff;
}

a { color: #1a56db; text-decoration: none; }
a:hover { text-decoration: underline; }

/* Header */
header {
  border-bottom: 1px solid #e5e7eb;
  padding: 1.25rem 1.5rem;
}
.header-inner {
  max-width: 900px;
  margin: 0 auto;
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
}
.site-name {
  font-size: 1.25rem;
  font-weight: 700;
  color: #1a1a1a;
  letter-spacing: -0.02em;
}
.site-tagline {
  font-size: 0.9rem;
  color: #6b7280;
}

/* Homepage */
.home-hero {
  max-width: 900px;
  margin: 3rem auto 2.5rem;
  padding: 0 1.5rem;
}
.home-hero h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: 0.75rem;
}
.home-hero p {
  font-size: 1.1rem;
  color: #4b5563;
  max-width: 580px;
}

.post-list {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem 4rem;
}
.post-list h2 {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #6b7280;
  margin-bottom: 1.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid #e5e7eb;
}
.post-card {
  padding: 1.5rem 0;
  border-bottom: 1px solid #f3f4f6;
}
.post-card:last-child { border-bottom: none; }
.post-card h3 { font-size: 1.15rem; font-weight: 600; margin-bottom: 0.4rem; line-height: 1.3; }
.post-card h3 a { color: #1a1a1a; }
.post-card h3 a:hover { color: #1a56db; text-decoration: none; }
.post-card p { font-size: 0.95rem; color: #4b5563; margin-bottom: 0.5rem; }
.post-meta { font-size: 0.8rem; color: #9ca3af; }

/* Article */
.article-wrap {
  max-width: 700px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 5rem;
}
.article-header { margin-bottom: 2.5rem; }
.article-header h1 {
  font-size: 1.9rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.25;
  margin-bottom: 0.75rem;
}
.article-header .article-meta { font-size: 0.85rem; color: #9ca3af; }

.article-body h2 {
  font-size: 1.3rem;
  font-weight: 700;
  margin: 2.5rem 0 0.75rem;
  letter-spacing: -0.01em;
}
.article-body h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin: 1.75rem 0 0.5rem;
}
.article-body p { margin-bottom: 1.1rem; }
.article-body ul, .article-body ol {
  margin: 0.75rem 0 1.1rem 1.5rem;
}
.article-body li { margin-bottom: 0.4rem; }
.article-body strong { font-weight: 600; }
.article-body hr { border: none; border-top: 1px solid #e5e7eb; margin: 2rem 0; }

.article-body table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  margin: 1.25rem 0;
}
.article-body th {
  text-align: left;
  padding: 0.5rem 0.75rem;
  background: #f9fafb;
  border-bottom: 2px solid #e5e7eb;
  font-weight: 600;
}
.article-body td {
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid #e5e7eb;
  vertical-align: top;
}
.article-body tr:last-child td { border-bottom: none; }

.affiliate-box {
  background: #f0f7ff;
  border-left: 4px solid #1a56db;
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  font-size: 0.95rem;
  border-radius: 0 6px 6px 0;
}

.article-note {
  font-size: 0.85rem;
  color: #6b7280;
  font-style: italic;
  background: #f9fafb;
  padding: 0.75rem 1rem;
  border-radius: 4px;
  margin: 1rem 0;
}

/* Footer */
footer {
  border-top: 1px solid #e5e7eb;
  padding: 2rem 1.5rem;
  font-size: 0.85rem;
  color: #9ca3af;
  text-align: center;
}

@media (max-width: 640px) {
  body { font-size: 17px; }
  .home-hero h1 { font-size: 1.6rem; }
  .article-header h1 { font-size: 1.5rem; }
}