Quiero que la flecha se mueva hacia arriba cuando abra la opción desplegable de selección.
<select class="form-select" aria-label="Default select example"> <option selected>Open this select menu</option> <option value="1">One</option> <option value="2">Two</option> <option value="3">Three</option> </select>Toma, prueba este,
select{ background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-chevron-down" viewBox="0 0 16 16"><path fill-rule="evenodd" d="M1.646 4.646a.5.5 0 0 1 .708 0L8 10.293l5.646-5.647a.5.5 0 0 1 .708.708l-6 6a.5.5 0 0 1-.708 0l-6-6a.5.5 0 0 1 0-.708z"/></svg>') no-repeat right #ddd; -webkit-appearance: none; padding-right: 1.5rem; background-position: right 0.1rem center; } select:focus { background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-chevron-up" viewBox="0 0 16 16"><path fill-rule="evenodd" d="M7.646 4.646a.5.5 0 0 1 .708 0l6 6a.5.5 0 0 1-.708.708L8 5.707l-5.646 5.647a.5.5 0 0 1-.708-.708l6-6z"/></svg>') no-repeat right #ddd; background-position: right 0.1rem center; } <select class="form-select" aria-label="Default select example"> <option selected>Open this select menu</option> <option value="1">One</option> <option value="2">Two</option> <option value="3">Three</option> </select>Los íconos son de bootstrap, Chevron arriba y Chevron abajo