/* Accordion summary button — remove default ring */
lightning-accordion-section::part(button) {
    outline: none;
    box-shadow: none;
}

/* Custom 15-px focus ring that matches your card radius */
lightning-accordion-section::part(button):focus-visible {
    outline: 2px solid var(--lwc-brandAccessible, yellow);
    outline-offset: -1px;
    border-radius: 15px;
}

/* Rounded first & last headers */
lightning-accordion-section:first-child::part(button) {
    border-top-left-radius: 15px;
    border-top-right-radius: 15px;
}
lightning-accordion-section:last-child::part(button) {
    border-bottom-left-radius: 15px;
    border-bottom-right-radius: 15px;
}