#callUS {
  /* ... Your existing positioning code (margin, anchor, etc) ... */
  margin: 0;
  position-anchor: --call__button;
  top: anchor(bottom);
  left: anchor(left);
  margin-top: 0.5rem;
  
  /* 1. Set the "Visible" state */
  opacity: 1;
  transform: translateY(0) scaleY(1);
  transform-origin: top;
  transition: 
    opacity 0.3s ease-out, 
    transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1), /* Adds a tiny "bounce" */
    display 0.3s allow-discrete, 
    overlay 0.3s allow-discrete;
}

/* 2. Set the "Hidden" state (Before it enters and after it leaves) */
#callUS:not(:popover-open) {
  opacity: 0;
  transform: translateY(-10px) scaleY(0.95);
}

/* 3. The Magic: The "Entry" state */
@starting-style {
  #callUS:popover-open {
    opacity: 0;
    transform: translateY(-10px) scaleY(0.95);
  }
}

#callPOP{display:flex;flex-direction:column;margin:0;width:100%}
#callPOP li{margin-block:0 1rem;display:block !important;margin-inline:0}
#callPOP button{background:none;border:none;color:#222 !important;position:relative;padding-left:2rem;line-height:1.5;text-align:left;cursor:pointer;}
#callPOP button span{display:block;}
#callPOP button span:nth-child(2) {font-size: calc(10px + 8 * (100vw / 1920)) !important;}
#callPOP button:before{font-family:'1stAuto';content:'\e968';float:left;margin-inline:0 1rem;color:#222;position: absolute;left: 0;top: 50%;transform: translateY(-50%);font-size:1.5rem}
#callPOP a{color:#fff !important;}
/*.tippy-box{background:white;border:2px solid #222}*/
.tippy-box[data-theme~='white'] {background:white;border:2px solid #222;min-width:150px}