.howto-main {
  max-width: 920px;
  margin: 0 auto;
  padding: 0 1rem;
}
.howto-title {
  font-size: 2rem;
  color: #0a66c2;
  border-bottom: 3px solid #0a66c2;
  padding-bottom: 0.5rem;
  margin-bottom: 0.5rem;
}
.howto-subtitle {
  color: #666;
  font-size: 0.95rem;
  margin-top: 0;
  margin-bottom: 0.8rem;
}
.meta-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  margin-bottom: 2rem;
  font-size: 0.85rem;
  color: #555;
}
.meta-bar .meta-item {
  background: #eef4fb;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
}

.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: 0.2rem 0; font-size: 0.95rem; }
.toc a { color: #0a66c2; text-decoration: none; }
.toc a:hover { text-decoration: underline; }

.section {
  margin: 3rem 0;
}
.section > h2 {
  font-size: 1.4rem;
  color: #1a1a1a;
  border-left: 5px solid #0a66c2;
  padding-left: 0.7rem;
  margin: 2.5rem 0 1rem;
}
.section h3 {
  font-size: 1.15rem;
  color: #0a66c2;
  margin-top: 1.8rem;
  margin-bottom: 0.5rem;
}
.section h4 {
  font-size: 1rem;
  margin-top: 1.4rem;
  margin-bottom: 0.4rem;
  color: #1a1a1a;
}

.section p { line-height: 1.8; margin: 0.6rem 0; }
.section ul, .section ol { margin: 0.5rem 0; padding-left: 1.6rem; }
.section li { margin: 0.3rem 0; line-height: 1.7; }

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

.note, .tip, .warn, .pitfall {
  border-left: 4px solid;
  padding: 0.7rem 1rem;
  margin: 1rem 0;
  border-radius: 4px;
  background: #f7f9fc;
}
.note { border-color: #0a66c2; background: #eef4fb; }
.tip { border-color: #2e7d32; background: #ecf7ec; }
.warn { border-color: #ed6c02; background: #fff7e6; }
.pitfall { border-color: #d32f2f; background: #fdecea; }
.note > strong, .tip > strong, .warn > strong, .pitfall > strong {
  display: inline-block;
  margin-right: 0.4rem;
}

.step-card {
  border: 1px solid #d0d7de;
  border-radius: 8px;
  padding: 1rem 1.4rem;
  margin: 1.5rem 0;
  background: #fff;
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}
.step-card .step-no {
  display: inline-block;
  background: #0a66c2;
  color: #fff;
  border-radius: 999px;
  padding: 0.15rem 0.7rem;
  font-size: 0.85rem;
  font-weight: 700;
  margin-right: 0.5rem;
}
.step-card h3 {
  display: inline;
  font-size: 1.1rem;
  margin: 0;
  color: #1a1a1a;
}

.diagram {
  background: #f6f8fa;
  border: 1px solid #d0d7de;
  border-radius: 6px;
  padding: 1rem;
  font-family: 'Consolas', 'Monaco', monospace;
  font-size: 0.85rem;
  line-height: 1.5;
  white-space: pre;
  overflow-x: auto;
  color: #24292f;
}

.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) {
  .howto-title { font-size: 1.5rem; }
  .section > h2 { font-size: 1.2rem; }
}