primevue-mirror/apps/showcase/assets/styles/layout/_designer.scss

.designer {
    [type='color'] {
        margin-top: -4px;
        border: 0 none;
        padding: 0;
        -webkit-appearance: none;
        -moz-appearance: none;
        appearance: none;
        width: 28px;
        height: 28px;
        background-color: transparent;
        border: none;
        cursor: pointer;
    }
    
    [type='color']::-webkit-color-swatch {
        border-radius: 4px;
        width: 24px;
        height: 24px;
        border: 0 none;
    }

    .p-fieldset-toggleable > .p-fieldset-legend:hover {
        background: transparent;
    }

}