/* ==========================================================
   鲲鹏AI · SEO 专题页样式（/seo/*.html）
   目标：长文可读性 —— 大厂文档/资讯站的做法
   - 正文行高 1.9，中文长文最舒服
   - 每段不超过 76 字符，行宽控制在 720px 内
   - H2 上方留白明显大于下方，层级一眼可辨
   - 强调色只用品牌色，不用彩色高亮
   ========================================================== */

.seo-main {
  background: #fff;
}

/* ---------- Hero ---------- */
.seo-hero {
  background: var(--bg-sub, #f7f8fa);
  border-bottom: 1px solid var(--line, #e7e9ec);
  padding: 48px 0 40px;
}

.seo-hero__cat {
  display: inline-block;
  background: var(--brand-weak, #ecf2fe);
  color: var(--brand, #0052d9);
  font-size: var(--fs-12, 12px);
  padding: 4px 10px;
  border-radius: var(--r-xs, 4px);
  margin-bottom: 16px;
}

.seo-hero h1 {
  font-size: var(--fs-32, 32px);
  font-weight: var(--fw-bold, 600);
  line-height: 1.35;
  letter-spacing: -.02em;
  color: var(--ink-1, rgba(0, 0, 0, .9));
  margin: 0 0 16px;
  max-width: 900px;
}

.seo-hero .lead {
  font-size: var(--fs-16, 16px);
  line-height: 1.85;
  color: var(--ink-2, rgba(0, 0, 0, .75));
  max-width: 780px;
  margin: 0;
}

.seo-hero__meta {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  margin-top: 24px;
  font-size: var(--fs-12, 12px);
  color: var(--ink-4, rgba(0, 0, 0, .38));
}

/* ---------- 目录 ---------- */
.seo-toc {
  padding: 28px 0;
  background: #fff;
  border-bottom: 1px solid var(--line-soft, #f0f1f3);
}

.seo-toc__title {
  font-size: var(--fs-16, 16px);
  font-weight: var(--fw-medium, 500);
  color: var(--ink-1, rgba(0, 0, 0, .9));
  margin: 0 0 14px;
}

.seo-toc__list {
  counter-reset: toc;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px 32px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.seo-toc__list li { counter-increment: toc; }

.seo-toc__list a {
  display: flex;
  gap: 10px;
  font-size: var(--fs-14, 14px);
  line-height: 1.7;
  color: var(--ink-2, rgba(0, 0, 0, .75));
  transition: color .18s;
}

.seo-toc__list a::before {
  content: counter(toc, decimal-leading-zero);
  flex-shrink: 0;
  color: var(--ink-4, rgba(0, 0, 0, .38));
  font-variant-numeric: tabular-nums;
  font-weight: var(--fw-medium, 500);
}

.seo-toc__list a:hover { color: var(--brand, #0052d9); }
.seo-toc__list a:hover::before { color: var(--brand, #0052d9); }

/* ---------- 正文 ---------- */
.seo-body {
  padding: 40px 0 24px;
}

.seo-block {
  margin-bottom: 40px;
  scroll-margin-top: 76px;   /* 顶栏 sticky，锚点定位不要被遮住 */
}

.seo-block h2 {
  font-size: var(--fs-24, 24px);
  font-weight: var(--fw-bold, 600);
  line-height: 1.45;
  letter-spacing: -.01em;
  color: var(--ink-1, rgba(0, 0, 0, .9));
  margin: 0 0 16px;
  padding-left: 14px;
  border-left: 3px solid var(--brand, #0052d9);
}

.seo-block p {
  font-size: 15px;
  line-height: 1.95;
  color: var(--ink-2, rgba(0, 0, 0, .75));
  margin: 0 0 14px;
  max-width: 780px;
}

.seo-block p strong {
  color: var(--ink-1, rgba(0, 0, 0, .9));
  font-weight: var(--fw-medium, 500);
}

/* 要点列表 */
.seo-list {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  max-width: 820px;
}

.seo-list li {
  position: relative;
  padding-left: 22px;
  margin-bottom: 14px;
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--ink-2, rgba(0, 0, 0, .75));
}

.seo-list li::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 13px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--brand, #0052d9);
}

.seo-list li strong {
  color: var(--ink-1, rgba(0, 0, 0, .9));
  font-weight: var(--fw-medium, 500);
}

/* ---------- FAQ ---------- */
.seo-faq {
  padding: 40px 0;
  background: var(--bg-sub, #f7f8fa);
  border-top: 1px solid var(--line, #e7e9ec);
  border-bottom: 1px solid var(--line, #e7e9ec);
  scroll-margin-top: 76px;
}

.seo-faq__item {
  background: #fff;
  border: 1px solid var(--line, #e7e9ec);
  border-radius: var(--r-sm, 8px);
  padding: 20px 24px;
  margin-top: 12px;
}

.seo-faq__item h3 {
  font-size: var(--fs-16, 16px);
  font-weight: var(--fw-medium, 500);
  line-height: 1.6;
  color: var(--ink-1, rgba(0, 0, 0, .9));
  margin: 0 0 10px;
  padding-left: 26px;
  position: relative;
}

.seo-faq__item h3::before {
  content: "Q";
  position: absolute;
  left: 0;
  top: 3px;
  width: 18px;
  height: 18px;
  border-radius: var(--r-xs, 4px);
  background: var(--brand-weak, #ecf2fe);
  color: var(--brand, #0052d9);
  font-size: 11px;
  font-weight: var(--fw-bold, 600);
  display: flex;
  align-items: center;
  justify-content: center;
}

.seo-faq__item p {
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--ink-2, rgba(0, 0, 0, .75));
  margin: 0;
  padding-left: 26px;
  max-width: 800px;
}

/* ---------- 相关链接区 ---------- */
.seo-related {
  padding: 40px 0;
}

.seo-related--gray {
  background: var(--bg-sub, #f7f8fa);
  border-top: 1px solid var(--line, #e7e9ec);
}

.seo-related__desc {
  font-size: var(--fs-14, 14px);
  color: var(--ink-3, rgba(0, 0, 0, .56));
  margin: -6px 0 20px;
}

.seo-rel-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.seo-rel {
  display: block;
  background: #fff;
  border: 1px solid var(--line, #e7e9ec);
  border-radius: var(--r-sm, 8px);
  padding: 18px 20px;
  transition: border-color .18s, box-shadow .18s, transform .18s;
}

.seo-rel:hover {
  border-color: var(--brand-border, #bed6fb);
  box-shadow: var(--sh-2, 0 6px 16px rgba(0, 0, 0, .08));
  transform: translateY(-2px);
}

.seo-rel__name {
  font-size: var(--fs-14, 14px);
  font-weight: var(--fw-medium, 500);
  color: var(--ink-1, rgba(0, 0, 0, .9));
  line-height: 1.6;
}

.seo-rel__sub {
  font-size: var(--fs-13, 13px);
  color: var(--ink-3, rgba(0, 0, 0, .56));
  margin-top: 6px;
  line-height: 1.7;
}

.seo-rel__go {
  font-size: var(--fs-13, 13px);
  color: var(--brand, #0052d9);
  margin-top: 10px;
}

.seo-rel__cat {
  display: inline-block;
  font-size: var(--fs-12, 12px);
  color: var(--brand, #0052d9);
  background: var(--brand-weak, #ecf2fe);
  padding: 2px 8px;
  border-radius: var(--r-xs, 4px);
  margin-bottom: 10px;
}

.seo-rel--seo .seo-rel__name {
  font-size: var(--fs-14, 14px);
  line-height: 1.7;
}

/* ---------- CTA ---------- */
.seo-cta {
  padding: 48px 0;
  background: #0d1117;
  color: #fff;
  text-align: center;
}

.seo-cta h2 {
  font-size: var(--fs-24, 24px);
  font-weight: var(--fw-bold, 600);
  letter-spacing: -.01em;
  color: #fff;
  margin: 0 0 14px;
}

.seo-cta p {
  font-size: var(--fs-14, 14px);
  line-height: 1.85;
  color: rgba(255, 255, 255, .7);
  margin: 0 auto 26px;
  max-width: 680px;
}

.seo-cta__btns {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.seo-cta .btn--ghost {
  color: rgba(255, 255, 255, .82);
  border-color: rgba(255, 255, 255, .2);
}

.seo-cta .btn--ghost:hover {
  background: rgba(255, 255, 255, .1);
  color: #fff;
  border-color: rgba(255, 255, 255, .32);
}

/* ==========================================================
   响应式
   ========================================================== */
@media (max-width: 1024px) {
  .seo-rel-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .seo-hero { padding: 32px 0 28px; }
  .seo-hero h1 { font-size: 22px; }
  .seo-hero .lead { font-size: var(--fs-14, 14px); line-height: 1.85; }

  .seo-toc { padding: 22px 0; }
  .seo-toc__list { grid-template-columns: 1fr; gap: 6px; }

  .seo-body { padding: 28px 0 16px; }
  .seo-block { margin-bottom: 32px; }
  .seo-block h2 { font-size: 19px; padding-left: 11px; }
  .seo-block p { font-size: 14.5px; line-height: 1.9; }
  .seo-list li { font-size: 14px; margin-bottom: 12px; }

  .seo-faq { padding: 28px 0; }
  .seo-faq__item { padding: 16px 18px; }
  .seo-faq__item h3 { font-size: 15px; }
  .seo-faq__item p { font-size: 14px; padding-left: 0; }

  .seo-related { padding: 28px 0; }
  .seo-rel-grid { grid-template-columns: 1fr; gap: 10px; }

  .seo-cta { padding: 36px 0; }
  .seo-cta h2 { font-size: 19px; }
  .seo-cta__btns .btn { height: 42px; }
}

/* ==========================================================
   首页 SEO 引流区（AI 培训与项目指南）
   ========================================================== */
.seo-guide {
  padding: 56px 0;
  background: #fff;
  border-bottom: 1px solid var(--line, #e7e9ec);
}

.seo-guide__lead {
  max-width: 820px;
  margin: -8px 0 28px;
}

.seo-guide__lead p {
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--ink-2, rgba(0, 0, 0, .75));
  margin: 0;
}

.seo-guide__lead strong {
  color: var(--ink-1, rgba(0, 0, 0, .9));
  font-weight: var(--fw-medium, 500);
}

.seo-guide__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.seo-guide__card {
  display: block;
  background: #fff;
  border: 1px solid var(--line, #e7e9ec);
  border-radius: var(--r-sm, 8px);
  padding: 22px 24px 20px;
  transition: border-color .18s, box-shadow .18s, transform .18s;
}

.seo-guide__card:hover {
  border-color: var(--brand-border, #bed6fb);
  box-shadow: var(--sh-2, 0 6px 16px rgba(0, 0, 0, .08));
  transform: translateY(-2px);
}

.seo-guide__cat {
  display: inline-block;
  font-size: var(--fs-12, 12px);
  color: var(--brand, #0052d9);
  background: var(--brand-weak, #ecf2fe);
  padding: 2px 8px;
  border-radius: var(--r-xs, 4px);
  margin-bottom: 12px;
}

.seo-guide__card h3 {
  font-size: var(--fs-16, 16px);
  font-weight: var(--fw-medium, 500);
  line-height: 1.6;
  color: var(--ink-1, rgba(0, 0, 0, .9));
  margin: 0 0 10px;
}

.seo-guide__card p {
  font-size: var(--fs-13, 13px);
  line-height: 1.85;
  color: var(--ink-3, rgba(0, 0, 0, .56));
  margin: 0;
}

.seo-guide__go {
  display: inline-block;
  margin-top: 14px;
  font-size: var(--fs-13, 13px);
  color: var(--brand, #0052d9);
}

/* 主 CTA 卡：浅底区分层次 */
.seo-guide__card--cta {
  background: var(--bg-sub, #f7f8fa);
  border-color: var(--brand-border, #bed6fb);
}

@media (max-width: 1024px) {
  .seo-guide__grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .seo-guide { padding: 36px 0; }
  .seo-guide__lead { margin: -6px 0 20px; }
  .seo-guide__lead p { font-size: 14px; line-height: 1.85; }
  .seo-guide__grid { grid-template-columns: 1fr; gap: 10px; }
  .seo-guide__card { padding: 18px 20px 16px; }
  .seo-guide__card h3 { font-size: 15px; }
}