.session-main {
  max-width: 920px;
  margin: 0 auto;
  padding: 0 1rem;
}
.session-title {
  font-size: 2rem;
  color: #0a66c2;
  border-bottom: 3px solid #0a66c2;
  padding-bottom: 0.5rem;
  margin-bottom: 0.5rem;
}
.session-subtitle {
  color: #666;
  font-size: 0.95rem;
  margin-top: 0;
  margin-bottom: 2rem;
}
.toc {
  background: #f5f8fb;
  border: 1px solid #d6e3ee;
  border-radius: 6px;
  padding: 1rem 1.5rem;
  margin-bottom: 2.5rem;
}
.toc h2 { margin-top: 0; font-size: 1.1rem; color: #0a66c2; }
.toc ol { padding-left: 1.4rem; margin: 0; }
.toc li { padding: 0.25rem 0; font-size: 0.95rem; }
.toc a { color: #0a66c2; text-decoration: none; }
.toc a:hover { text-decoration: underline; }

.qa-section {
  margin-bottom: 3rem;
  scroll-margin-top: 1rem;
}
.qa-section > h2 {
  font-size: 1.3rem;
  color: #1a1a1a;
  border-left: 5px solid #0a66c2;
  padding-left: 0.7rem;
  margin-top: 2.5rem;
}

.qa-block {
  border-radius: 8px;
  padding: 1rem 1.25rem;
  margin: 1rem 0;
  position: relative;
}
.qa-block.question {
  background: #eef4fb;
  border-left: 4px solid #0a66c2;
}
.qa-block.answer {
  background: #fafafa;
  border-left: 4px solid #888;
}
.qa-label {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: #555;
  margin-bottom: 0.4rem;
  text-transform: none;
}
.qa-block.question .qa-label { color: #0a66c2; }
.qa-content > *:first-child { margin-top: 0; }
.qa-content > *:last-child { margin-bottom: 0; }

.qa-content h1, .qa-content h2, .qa-content h3, .qa-content h4 {
  margin-top: 1.2rem;
  margin-bottom: 0.5rem;
  color: #1a1a1a;
}
.qa-content h1 { font-size: 1.3rem; }
.qa-content h2 { font-size: 1.15rem; }
.qa-content h3 { font-size: 1.05rem; }
.qa-content h4 { font-size: 1rem; }

.qa-content p { line-height: 1.75; margin: 0.6rem 0; }
.qa-content ul, .qa-content ol { margin: 0.5rem 0; padding-left: 1.6rem; }
.qa-content li { margin: 0.25rem 0; line-height: 1.7; }

.qa-content code {
  background: #eef0f2;
  padding: 0.1em 0.4em;
  border-radius: 3px;
  font-size: 0.92em;
  font-family: 'Consolas', 'Monaco', monospace;
}
.qa-content pre {
  background: #1e1e1e;
  color: #eee;
  padding: 0.9rem 1rem;
  border-radius: 6px;
  overflow-x: auto;
  font-size: 0.88rem;
  line-height: 1.55;
}
.qa-content pre code {
  background: transparent;
  color: #eee;
  padding: 0;
}
.qa-content table {
  border-collapse: collapse;
  width: 100%;
  margin: 1rem 0;
  font-size: 0.92rem;
}
.qa-content th, .qa-content td {
  border: 1px solid #d0d7de;
  padding: 0.5rem 0.75rem;
  text-align: left;
  vertical-align: top;
}
.qa-content thead th {
  background: #eef4fb;
  color: #0a66c2;
}
.qa-content hr {
  border: 0;
  border-top: 1px dashed #ccc;
  margin: 1rem 0;
}

.back-to-top {
  margin-top: 3rem;
  text-align: center;
  font-size: 0.95rem;
}
.back-to-top a { color: #0a66c2; text-decoration: none; }
.back-to-top a:hover { text-decoration: underline; }

@media (max-width: 600px) {
  .session-title { font-size: 1.5rem; }
  .qa-section > h2 { font-size: 1.1rem; }
  .qa-block { padding: 0.75rem 0.9rem; }
}