:root{
  --ebc-bg:#ffffff;
  --ebc-fg:#111827;
  --ebc-muted:#6b7280;
  --ebc-border:#e5e7eb;
  --ebc-primary:#2563eb;
  --ebc-primary-fg:#ffffff;
}
.ebc-launcher{
  position:fixed; right:18px; bottom:18px;
  width:54px; height:54px; border-radius:999px;
  border:1px solid var(--ebc-border);
  background:var(--ebc-primary); color:var(--ebc-primary-fg);
  cursor:pointer; box-shadow:0 10px 25px rgba(0,0,0,.12);
  font:600 14px/1 system-ui,-apple-system,Segoe UI,Roboto,Arial;
}
.ebc-panel{
  position:fixed; right:18px; bottom:84px;
  width:340px; height:460px;
  border:1px solid var(--ebc-border);
  background:var(--ebc-bg); color:var(--ebc-fg);
  border-radius:14px; box-shadow:0 14px 40px rgba(0,0,0,.14);
  display:none; overflow:hidden;
  font:400 13px/1.35 system-ui,-apple-system,Segoe UI,Roboto,Arial;
}
.ebc-panel.ebc-open{ display:flex; flex-direction:column; }
.ebc-header{
  padding:12px 12px;
  border-bottom:1px solid var(--ebc-border);
  display:flex; align-items:center; justify-content:space-between;
}
.ebc-title{ font-weight:700; font-size:13px; }
.ebc-close{ border:0; background:transparent; cursor:pointer; color:var(--ebc-muted); font-size:18px; }
.ebc-messages{ padding:12px; gap:8px; display:flex; flex-direction:column; overflow:auto; flex:1; }
.ebc-msg{ max-width:85%; padding:9px 10px; border-radius:12px; border:1px solid var(--ebc-border); background:#f9fafb; }
.ebc-msg.ebc-user{ margin-left:auto; background:#eff6ff; border-color:#dbeafe; }
.ebc-meta{ font-size:11px; color:var(--ebc-muted); margin-top:2px; }
.ebc-inputbar{
  padding:10px; border-top:1px solid var(--ebc-border);
  display:flex; gap:8px; align-items:center;
}
.ebc-input{
  flex:1; border:1px solid var(--ebc-border);
  border-radius:10px; padding:9px 10px;
  outline:none;
}
.ebc-send{
  border:1px solid var(--ebc-border);
  background:var(--ebc-primary); color:var(--ebc-primary-fg);
  border-radius:10px; padding:9px 12px;
  cursor:pointer; font-weight:600;
}
.ebc-error{ color:#b91c1c; font-size:12px; padding:0 12px 10px; display:none; }