body {
  font-family: 'Inter', sans-serif;
  background: #f9fafb;
  color: #111827;
  margin: 0;
  line-height: 1.7;
}

a {
  color: #1d4ed8;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

main {
  padding: 32px 18px 64px;
  max-width: 1100px;
  margin: 0 auto;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  margin-bottom: 24px;
}

.page-header h1 {
  font-size: 2.4rem;
  margin-bottom: 0.75rem;
  color: #0f172a;
}

.page-header p {
  margin: 0;
  color: #4b5563;
  font-size: 1.05rem;
}

.blog-layout {
  display: grid;
  grid-template-columns: minmax(260px, 300px) 1fr;
  gap: 24px;
  margin-top: 32px;
}

.post-actions {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.toggle-button {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: 1px solid #1d4ed8;
  background: #1d4ed8;
  color: #ffffff;
  padding: 10px 16px;
  border-radius: 999px;
  font-weight: 600;
  cursor: pointer;
  width: fit-content;
  transition: background 0.2s ease, color 0.2s ease, border 0.2s ease;
}

.toggle-button.secondary {
  background: #ffffff;
  color: #1d4ed8;
}

.post-list {
  background: #ffffff;
  border: 1px solid #e5e7eb;
  border-radius: 12px;
  padding: 16px;
  max-height: 480px;
  overflow-y: auto;
  display: none;
}

.post-list.active {
  display: block;
}

.post-list h2 {
  font-size: 1.1rem;
  margin-bottom: 12px;
  color: #0f172a;
}

.post-item {
  padding: 10px 12px;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.2s ease;
  color: #1f2937;
  font-size: 0.98rem;
}

.post-item:hover,
.post-item.active {
  background: #e0f2fe;
  color: #0c4a6e;
}

.viewer {
  background: #ffffff;
  border: 1px solid #e5e7eb;
  border-radius: 12px;
  padding: 24px;
  min-height: 420px;
  box-shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
  overflow-wrap: anywhere;
}

.viewer h1,
.viewer h2,
.viewer h3 {
  color: #0f172a;
}

.viewer h1 {
  margin-top: 0;
}

.viewer pre {
  background: #0f172a;
  color: #f8fafc;
  padding: 14px;
  border-radius: 8px;
  overflow-x: auto;
  font-size: 0.95rem;
}

.viewer code {
  font-family: 'Fira Code', 'Consolas', 'Courier New', monospace;
}

.viewer blockquote {
  border-left: 4px solid #1d4ed8;
  background: #eff6ff;
  padding: 10px 16px;
  color: #1e3a8a;
}

.viewer ul {
  padding-left: 20px;
}

.viewer ul li {
  margin-bottom: 6px;
}

.empty-state {
  margin-top: 40px;
  border: 1px dashed #d1d5db;
  border-radius: 12px;
  padding: 48px 24px;
  text-align: center;
  color: #6b7280;
}

.status-message {
  margin-top: 12px;
  font-size: 0.9rem;
  color: #1f2937;
  display: none;
}

.status-message.visible {
  display: block;
}

@media (max-width: 900px) {
  main {
    padding: 28px 18px 48px;
  }

  .blog-layout {
    grid-template-columns: 1fr;
  }

  .post-actions {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 12px;
  }

  .toggle-button {
    width: auto;
  }

  .post-list {
    max-height: none;
  }
}

@media (max-width: 700px) {
  main {
    padding: 24px 16px 44px;
  }

  .page-header h1 {
    font-size: 2rem;
  }

  .page-header p {
    font-size: 0.98rem;
  }

  .viewer {
    padding: 20px;
  }

  .post-actions {
    width: 100%;
  }

  .toggle-button {
    width: 100%;
    justify-content: center;
  }

  .status-message {
    text-align: center;
    width: 100%;
  }
}

@media (max-width: 540px) {
  main {
    padding: 22px 14px 40px;
  }

  .page-header h1 {
    font-size: 1.75rem;
  }

  .page-header p {
    font-size: 0.94rem;
  }

  .post-actions {
    gap: 10px;
  }

  .toggle-button {
    padding: 10px 14px;
    font-size: 0.95rem;
  }

  .post-list {
    padding: 12px;
  }

  .post-item {
    padding: 9px 10px;
    font-size: 0.94rem;
  }

  .viewer {
    padding: 18px 16px;
  }

  .viewer pre {
    font-size: 0.88rem;
    padding: 12px;
  }

  .viewer blockquote {
    padding: 10px 14px;
  }
}

@media (max-width: 420px) {
  main {
    padding: 20px 12px 36px;
  }

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

  .toggle-button {
    font-size: 0.9rem;
  }

  .viewer {
    padding: 16px 14px;
  }

  .viewer h1 {
    font-size: 1.4rem;
  }

  .viewer h2 {
    font-size: 1.2rem;
  }

  .viewer h3 {
    font-size: 1.05rem;
  }

  .viewer pre {
    font-size: 0.82rem;
  }
}