/* ============================================================
   baidu-seo.css · 百度SEO优化
   Hero 骨架：H4 大圆叠图（左侧大圆装饰 + 图文错位）
   ============================================================ */

/* ---------- Hero H4 大圆叠图 ---------- */
.bd-hero{padding:60px 0 90px;background:var(--bg);overflow:hidden;position:relative}
.bd-hero-x{top:40%;left:0;right:0;opacity:.3}
.bd-circle{
  position:absolute;left:-120px;top:50%;transform:translateY(-50%);
  width:420px;height:420px;border-radius:50%;
  background:var(--blue);opacity:.35;
}
.bd-hero-in{display:grid;grid-template-columns:1fr 1.1fr;gap:48px;align-items:center;position:relative;z-index:2}
.bd-hero-media img{width:100%;border-radius:var(--r-lg);box-shadow:var(--shadow)}
.bd-hero-text h1{font-size:clamp(30px,4vw,48px);font-weight:800;margin:14px 0 18px}
.bd-hero-text h1 em{font-style:normal;color:var(--blue-ink);background:linear-gradient(transparent 65%,var(--yellow) 65%);padding:0 6px}
.bd-hero-text p{color:var(--muted);font-size:16px;margin-bottom:24px;max-width:520px}
.bd-hero-cta{display:flex;gap:14px;flex-wrap:wrap}

/* ---------- 对勾清单（section 2） ---------- */
.bd-check{background:var(--white);overflow:hidden}
.bd-check-v{left:30px;top:60px;bottom:60px;opacity:.25}
.bd-check-list{margin-left:50px;display:flex;flex-direction:column;gap:14px;max-width:820px}
.bd-check-list li{
  display:flex;gap:16px;align-items:flex-start;
  background:var(--bg);border:2px solid var(--line);border-radius:var(--r-md);
  padding:16px 22px;
}
.bd-check-list .ic{
  flex:none;width:32px;height:32px;border-radius:50%;
  background:var(--green);color:#fff;display:flex;align-items:center;justify-content:center;
  font-size:16px;margin-top:2px;
}
.bd-check-list h3{margin-bottom:4px;font-size:17px}
.bd-check-list p{color:var(--muted);font-size:14.5px}

/* ---------- 四块异形卡（section 3） ---------- */
.bd-algo{background:var(--bg);overflow:hidden}
.bd-algo-x{top:50%;left:0;right:0;opacity:.25}
.bd-algo-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;position:relative;z-index:2}
.bd-algo-card{
  background:var(--white);border:2px solid var(--line);border-radius:var(--r-lg);
  padding:28px 22px;position:relative;
}
.bd-algo-card:nth-child(odd){transform:translateY(20px)}
.bd-algo-no{
  position:absolute;top:-14px;right:18px;
  width:36px;height:36px;border-radius:50%;
  background:var(--yellow);font-weight:800;
  display:flex;align-items:center;justify-content:center;
}
.bd-algo-card h3{margin-bottom:8px;font-size:18px}
.bd-algo-card p{color:var(--muted);font-size:14px}

/* ---------- 漏斗步骤（section 4） ---------- */
.bd-fix{background:var(--white)}
.bd-fix-list{max-width:760px;margin:0 auto;display:flex;flex-direction:column;gap:0}
.bd-fix-step{
  display:flex;gap:20px;align-items:center;
  padding:18px 24px;background:var(--cream);
  border:2px solid var(--line);border-radius:var(--r-md);
  margin-bottom:-2px;
}
.bd-fix-step:nth-child(1){border-radius:var(--r-md) var(--r-md) 0 0}
.bd-fix-step:nth-child(4){border-radius:0 0 var(--r-md) var(--r-md);margin-bottom:0}
.bd-fix-no{
  flex:none;width:44px;height:44px;border-radius:50%;
  background:var(--blue);color:#fff;font-weight:800;
  display:flex;align-items:center;justify-content:center;
}
.bd-fix-step h3{font-size:17px;margin-bottom:4px}
.bd-fix-step p{color:var(--muted);font-size:14.5px}

/* ---------- 左文右图（section 5） ---------- */
.bd-tool{background:var(--bg)}
.bd-tool-in{display:grid;grid-template-columns:1.1fr 1fr;gap:48px;align-items:center}
.bd-tool-text h2{font-size:clamp(24px,3vw,32px);margin-bottom:14px}
.bd-tool-text>p{color:var(--muted);margin-bottom:18px}
.bd-tool-media img{width:100%}

/* ---------- 案例卡（section 6） ---------- */
.bd-case{background:var(--white)}
.bd-case-grid{display:grid;grid-template-columns:1fr 1fr;gap:24px;max-width:860px;margin:0 auto}
.bd-case-card{
  display:block;border-radius:var(--r-lg);overflow:hidden;
  border:2px solid var(--line);transition:transform .3s,box-shadow .3s;
}
.bd-case-card:hover{transform:translateY(-5px);box-shadow:var(--shadow)}
.bd-case-card img{width:100%;height:220px;object-fit:cover}
.bd-case-cap{display:block;padding:16px 18px;background:var(--bg)}
.bd-case-cap b{display:block;font-size:16px}
.bd-case-cap i{font-style:normal;color:var(--muted);font-size:13.5px}
.bd-case-more{text-align:center;margin-top:30px;font-weight:700}

/* ---------- FAQ（section 7） ---------- */
.bd-faq{background:var(--bg)}
.bd-faq-list{max-width:820px;margin:0 auto;display:flex;flex-direction:column;gap:12px}
.bd-faq-item{
  background:var(--white);border:2px solid var(--line);border-radius:var(--r-md);
  padding:16px 22px;border-left:5px solid var(--blue);
}
.bd-faq-item summary{font-weight:800;cursor:pointer;list-style:none;position:relative;padding-right:26px}
.bd-faq-item summary::-webkit-details-marker{display:none}
.bd-faq-item summary::after{content:"+";position:absolute;right:0;top:0;font-size:20px;color:var(--blue-ink)}
.bd-faq-item[open] summary::after{content:"−"}
.bd-faq-item p{margin-top:10px;color:var(--muted);font-size:14.5px}

/* ---------- 站长平台（section 7.5） ---------- */
.bd-webmaster{background:var(--bg);overflow:hidden}
.bd-webmaster-v{left:30px;top:60px;bottom:60px;opacity:.2}
.bd-webmaster-in{margin-left:50px;display:grid;grid-template-columns:repeat(3,1fr);gap:18px;max-width:900px}
.bd-webmaster-block{
  background:var(--white);border:2px solid var(--line);border-radius:var(--r-md);
  padding:22px 24px;border-top:5px solid var(--blue-ink);
}
.bd-webmaster-block h3{margin-bottom:8px;font-size:17px}
.bd-webmaster-block p{color:var(--muted);font-size:14.5px;line-height:1.7}

/* ---------- CTA（section 8） ---------- */
.bd-cta{background:var(--white);padding-bottom:80px}
.bd-cta-band{
  background:linear-gradient(120deg,var(--blue-ink) 0%,#3a7fa8 100%);
  border-radius:var(--r-lg);padding:60px 40px;text-align:center;color:#fff;
  box-shadow:var(--shadow);position:relative;overflow:hidden;
}
.bd-cta-band h2{color:#fff;font-size:clamp(24px,3vw,34px);margin-bottom:14px}
.bd-cta-band p{color:#DCEEF8;max-width:560px;margin:0 auto 26px}
.bd-cta-actions{display:flex;gap:14px;justify-content:center;flex-wrap:wrap;margin-bottom:20px}
.bd-cta-contact{font-size:14px;color:#BEE0F2;font-weight:700;letter-spacing:.04em}

/* ---------- 响应式 ---------- */
@media (max-width:900px){
  .bd-hero-in,.bd-tool-in{grid-template-columns:1fr}
  .bd-circle{display:none}
  .bd-algo-grid{grid-template-columns:1fr 1fr}
  .bd-algo-card:nth-child(odd){transform:none}
  .bd-case-grid{grid-template-columns:1fr}
  .bd-check-list{margin-left:0}
  .bd-check-v{display:none}
  .bd-webmaster-in{grid-template-columns:1fr;margin-left:0}
  .bd-webmaster-v{display:none}
}