/* ========================================
   XuZhiShi — Footer (Apple-style, BCI+VR design)
   Brand bar + 5-col grid + contact bar + bottom
   ======================================== */

.footer{color:var(--text-secondary);padding:0;background:#fafafa;position:relative;z-index:1;border-top:none}
.footer-brand{display:flex;align-items:center;justify-content:space-between;padding:4rem clamp(1.5rem,8vw,6rem) 3rem;border-bottom:1px solid rgba(0,0,0,0.06)}
.footer-brand-left{display:flex;align-items:center;gap:1rem}
.footer-brand-left img{height:32px;width:auto;object-fit:contain}
.footer-brand-left span{font-size:0.875rem;color:var(--text-muted);font-weight:400;padding-left:1rem;border-left:1px solid rgba(0,0,0,0.1)}
.footer-back-top{width:40px;height:40px;border-radius:50%;border:1px solid rgba(0,0,0,0.08);background:var(--bg);display:grid;place-items:center;cursor:pointer;transition:all 0.3s var(--ease);text-decoration:none;color:var(--text-secondary);font-size:1rem}
.footer-back-top:hover{transform:translateY(-2px);box-shadow:0 4px 12px rgba(0,0,0,0.06);border-color:rgba(0,113,227,0.2);color:var(--primary)}
.footer-main{display:grid;grid-template-columns:2fr repeat(4,1fr);gap:2.5rem;padding:3rem clamp(1.5rem,8vw,6rem);border-bottom:1px solid rgba(0,0,0,0.06)}
.footer-intro{padding-right:2rem}
.footer-intro p{font-size:0.8125rem;color:var(--text-muted);line-height:1.7;margin-bottom:1.5rem}
.footer-social{display:flex;gap:0.75rem}
.footer-social a{width:32px;height:32px;border-radius:50%;background:rgba(0,0,0,0.04);display:grid;place-items:center;text-decoration:none;color:var(--text-muted);font-size:0.875rem;transition:all 0.3s var(--ease)}
.footer-social a:hover{background:var(--primary);color:#fff;transform:translateY(-2px)}
.footer-col h4{font-size:0.6875rem;font-weight:600;color:var(--text);margin-bottom:1.25rem;letter-spacing:0.08em;text-transform:uppercase}
.footer-col a{display:block;font-size:0.8125rem;color:var(--text-muted);text-decoration:none;margin-bottom:0.625rem;transition:color 0.2s}
.footer-col a:hover{color:var(--primary)}
.footer-contact-bar{display:flex;align-items:center;justify-content:space-between;gap:2rem;padding:2rem clamp(1.5rem,8vw,6rem);border-bottom:1px solid rgba(0,0,0,0.06)}
.footer-contact-items{display:flex;align-items:center;gap:2.5rem;flex-wrap:wrap}
.footer-contact-item{display:flex;align-items:center;gap:0.5rem;font-size:0.8125rem;color:var(--text-muted)}
.footer-contact-item svg{color:var(--primary);flex-shrink:0}
.footer-qrcode{display:flex;align-items:center;gap:0.75rem;flex-shrink:0}
.footer-qrcode-box{width:64px;height:64px;border-radius:10px;border:1px solid rgba(0,0,0,0.06);background:var(--bg);display:grid;place-items:center;overflow:hidden}
.footer-qrcode-box img{width:100%;height:100%;object-fit:cover}
.footer-qrcode-label{font-size:0.6875rem;color:var(--text-muted)}
.footer-bottom{padding:1.5rem clamp(1.5rem,8vw,6rem);display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:1rem;font-size:0.6875rem;color:var(--text-muted)}
.footer-bottom-links{display:flex;gap:1.5rem}
.footer-bottom-links a{color:var(--text-muted);text-decoration:none;transition:color 0.2s}
.footer-bottom-links a:hover{color:var(--primary)}

/* Footer responsive */
@media(max-width:1023px){
  .footer-main{grid-template-columns:1fr 1fr 1fr;gap:2rem}
  .footer-intro{grid-column:1/-1;padding-right:0}
}
@media(max-width:767px){
  .footer-brand{flex-direction:column;align-items:flex-start;gap:1rem;padding:3rem 1.5rem 2rem}
  .footer-main{grid-template-columns:1fr 1fr;gap:1.5rem;padding:2rem 1.5rem}
  .footer-intro{grid-column:1/-1}
  .footer-contact-bar{flex-direction:column;align-items:flex-start;gap:1.5rem;padding:2rem 1.5rem}
  .footer-contact-items{flex-direction:column;gap:0.75rem}
  .footer-bottom{flex-direction:column;text-align:center;padding:1.5rem}
  .footer-bottom-links{justify-content:center}
}