/* ============================================================
   西游记主题 · 学科页横幅（参考图样式）
   蓝天流云 + 远山 + 书法标语 + 角色位
   仅在 html[data-theme="xiyou"] 下显示；其他主题完全不渲染。
   ============================================================ */
.xyb{ display:none; }

html[data-theme="xiyou"] .xyb{
  display:flex; align-items:center; gap:14px; position:relative; overflow:hidden;
  margin:14px 0 16px; border-radius:22px; padding:18px 20px 12px; min-height:156px;
  background:linear-gradient(178deg,#8FCDEF 0%,#B6E1F7 30%,#EAF6FC 56%,#FFF4DE 84%,#FFE8C4 100%);
  border:1px solid rgba(198,148,86,.4);
  box-shadow:0 10px 26px rgba(150,100,50,.18);
}
/* 流云 */
html[data-theme="xiyou"] .xyb::before{
  content:''; position:absolute; inset:0; pointer-events:none;
  background-image:
    radial-gradient(ellipse 46px 15px at 18% 22%, rgba(255,255,255,.9), transparent 70%),
    radial-gradient(ellipse 30px 11px at 34% 33%, rgba(255,255,255,.75), transparent 70%),
    radial-gradient(ellipse 58px 18px at 56% 15%, rgba(255,255,255,.8), transparent 70%),
    radial-gradient(ellipse 36px 12px at 80% 28%, rgba(255,255,255,.7), transparent 70%);
}
/* 远山 + 金色地平线 */
html[data-theme="xiyou"] .xyb::after{
  content:''; position:absolute; left:0; right:0; bottom:0; height:64px; pointer-events:none;
  background:
    radial-gradient(ellipse 110px 54px at 16% 104%, rgba(196,158,104,.48), transparent 70%),
    radial-gradient(ellipse 170px 70px at 64% 108%, rgba(170,130,78,.4), transparent 70%),
    linear-gradient(180deg, rgba(255,246,226,0) 0%, #FFF3DA 72%);
}
html[data-theme="xiyou"] .xyb-txt{ position:relative; z-index:2; flex:1; min-width:0; padding-right:6px; }
html[data-theme="xiyou"] .xyb-slogan{
  font-size:23px; font-weight:900; color:#8E3A14; line-height:1.47; letter-spacing:4px;
  text-shadow:0 2px 0 rgba(255,255,255,.92), 0 6px 13px rgba(140,80,30,.16);
}
html[data-theme="xiyou"] .xyb-sub{ margin-top:9px; font-size:12.5px; font-weight:800; color:#9A6A38; letter-spacing:.05em; }

/* 角色位：Q 版立绘（透明 webp），站在远山线上 */
html[data-theme="xiyou"] .xyb-char{
  position:relative; z-index:2; flex:none; align-self:flex-end; width:142px; height:150px;
  display:flex; align-items:flex-end; justify-content:center;
  font-size:76px; line-height:1; filter:drop-shadow(0 7px 12px rgba(120,70,20,.32));
  animation:xybBob 3.8s ease-in-out infinite;
}
html[data-theme="xiyou"] .xyb-char img{ height:100%; width:auto; object-fit:contain; display:block; }
@keyframes xybBob{ 0%,100%{transform:translateY(0);} 50%{transform:translateY(-6px);} }

@media (max-width:640px){
  html[data-theme="xiyou"] .xyb{ padding:14px 16px 10px; min-height:124px; border-radius:18px; }
  html[data-theme="xiyou"] .xyb-slogan{ font-size:18px; letter-spacing:2px; }
  html[data-theme="xiyou"] .xyb-sub{ font-size:11.5px; margin-top:7px; }
  html[data-theme="xiyou"] .xyb-char{ width:100px; height:108px; font-size:58px; }
}