.about-section{
  position:relative;
  padding:88px 0 104px;
  background:var(--bg-soft);
  overflow:hidden;
}
.about-section::before{
  content:"";position:absolute;top:-220px;left:50%;
  transform:translateX(-50%);
  width:1000px;height:560px;border-radius:50%;
  background:radial-gradient(circle,rgba(0,184,169,.09),transparent 68%);
}

/* 正文卡片 */
.about-card{
  position:relative;z-index:2;
  max-width:920px;margin:0 auto;
  background:#fff;
  border-radius:28px;
  padding:64px 64px 60px;
  box-shadow:var(--sh-md);
  border:1px solid var(--line);
  overflow:hidden;
}
.about-card::before{
  content:"";position:absolute;top:0;left:0;right:0;height:4px;
  background:var(--grad-main);
}
.about-card::after{
  content:"";position:absolute;right:-90px;bottom:-90px;
  width:280px;height:280px;border-radius:50%;
  background:radial-gradient(circle,rgba(15,108,189,.07),transparent 68%);
  pointer-events:none;
}

/* 标题行 */
.about-head{
  display:flex;align-items:center;gap:18px;
  margin-bottom:32px;
}
.about-head .line{
  width:44px;height:4px;border-radius:4px;
  background:var(--grad-main);
  flex-shrink:0;
}
.about-head h2{
  font-size:clamp(22px,2.4vw,28px);
  font-weight:900;line-height:1.3;
  letter-spacing:-.5px;
}

/* 正文段落 */
.about-text{
  position:relative;z-index:2;
  font-size:16.5px;
  line-height:2.05;
  color:var(--text2);
  text-indent:2em;
}
.about-text strong{
  font-weight:900;
  color:var(--c-blue);
}
.about-text .hl{
  font-weight:900;
  background:var(--grad-blue-teal);
  -webkit-background-clip:text;background-clip:text;
  color:transparent;
}

/* 签名区 */
.about-sign{
  position:relative;z-index:2;
  margin-top:44px;padding-top:32px;
  border-top:1px dashed var(--line);
  display:flex;align-items:center;justify-content:space-between;
  gap:24px;flex-wrap:wrap;
}
.about-sign .who{
  display:flex;align-items:center;gap:14px;
}
.about-sign .who .mark{
  width:44px;height:44px;border-radius:13px;
  box-shadow:0 8px 22px rgba(15,108,189,.26);
  flex-shrink:0;
}
.about-sign .who b{
  display:block;font-size:15px;font-weight:900;color:var(--text);
  line-height:1.4;
}
.about-sign .who span{
  font-size:12.5px;color:var(--text3);
  letter-spacing:1.8px;font-weight:700;
}
.about-sign .btn{padding:12px 26px;font-size:14px;}

/* ============================================================
   PART 3 · 关于我们页面的响应式
   ============================================================ */
@media (max-width:980px){
  .about-card{padding:48px 40px 46px;}
}

@media (max-width:740px){
  .about-section{padding:60px 0 74px;}
  .about-card{padding:38px 26px 36px;border-radius:22px;}
  .about-text{font-size:15.5px;line-height:1.95;}
  .about-sign{flex-direction:column;align-items:flex-start;gap:22px;}
}

@media (max-width:430px){
  .about-card::after{display:none;}
}