/* ============================================
   Article Page — Blog Layout
   ============================================ */

/* --- Navigation --- */
.article-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background: rgba(10, 10, 10, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--gold-border);
}

.article-nav-back,
.article-nav-link {
  font-family: var(--font-sans);
  font-size: 0.8rem;
  color: var(--gold);
  text-decoration: none;
  letter-spacing: 0.1em;
  transition: opacity 0.3s ease;
}

.article-nav-back:hover,
.article-nav-link:hover {
  opacity: 0.6;
}

/* --- Article Container --- */
.article-page {
  max-width: 720px;
  margin: 0 auto;
  padding: 6rem 2rem 4rem;
}

/* --- Header --- */
.article-header {
  margin-bottom: 4rem;
  padding-bottom: 3rem;
  border-bottom: 1px solid var(--gold-border);
}

.article-hero-img {
  width: 100%;
  aspect-ratio: 1.91 / 1;
  overflow: hidden;
  border-radius: 2px;
  margin-bottom: 2rem;
}

.article-hero-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.article-meta {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--gold);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  margin-bottom: 1.5rem;
  opacity: 0.8;
}

.article-header h1 {
  font-family: var(--font-serif);
  font-size: 2.2rem;
  font-weight: 500;
  line-height: 1.4;
  color: var(--white);
  margin-bottom: 0.8rem;
}

.article-subtitle {
  font-family: var(--font-sans);
  font-size: 1rem;
  color: var(--gray-light);
  line-height: 1.6;
}

/* --- Body --- */
.article-body section {
  margin-bottom: 3.5rem;
}

.article-body h2 {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 500;
  color: var(--white);
  margin-bottom: 1.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid rgba(201, 169, 110, 0.15);
}

.article-body h3 {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--white);
  margin-top: 2rem;
  margin-bottom: 1rem;
}

.article-body p {
  font-family: 'Noto Serif JP', serif;
  font-size: 1.05rem;
  line-height: 2.2;
  color: rgba(232, 228, 223, 0.9);
  margin-bottom: 1.2rem;
}

.article-body strong {
  color: var(--white);
  font-weight: 600;
}

.article-body blockquote {
  margin: 2rem 0;
  padding: 1.5rem 2rem;
  border-left: 2px solid var(--gold);
  background: var(--gold-dim);
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-style: italic;
  line-height: 2;
  color: var(--white);
}

.article-body blockquote cite {
  display: block;
  margin-top: 0.8rem;
  font-size: 0.85rem;
  font-style: normal;
  color: var(--gray-light);
}

.article-body .formula-inline {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  text-align: center;
  padding: 1.5rem 0;
  color: var(--gold);
  letter-spacing: 0.05em;
}

/* --- Footer --- */
.article-footer {
  margin-top: 4rem;
  padding-top: 3rem;
  border-top: 1px solid var(--gold-border);
  text-align: center;
}

.article-footer-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 3rem;
}

.article-footer-link {
  font-family: var(--font-sans);
  font-size: 0.85rem;
  color: var(--gold);
  text-decoration: none;
  letter-spacing: 0.05em;
  transition: opacity 0.3s ease;
}

.article-footer-link:hover {
  opacity: 0.6;
}

.article-footer-cta {
  margin-bottom: 2rem;
}

.article-footer-cta p {
  font-family: 'Noto Serif JP', serif;
  font-size: 1.1rem;
  color: var(--gray-light);
  margin-bottom: 1.5rem;
}

.article-footer .footer-copy {
  font-size: 0.75rem;
  color: var(--gray);
  margin-top: 2rem;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .article-nav {
    padding: 0.8rem 1rem;
  }

  .article-page {
    padding: 5rem 1.2rem 3rem;
  }

  .article-header h1 {
    font-size: 1.6rem;
  }

  .article-body h2 {
    font-size: 1.25rem;
  }

  .article-body p {
    font-size: 0.95rem;
    line-height: 2;
  }

  .article-body blockquote {
    padding: 1rem 1.2rem;
    font-size: 1rem;
  }

  .article-footer-nav {
    flex-direction: column;
    gap: 1rem;
  }
}