om/node_modules/buefy/src/scss/components/_select.scss

.select {
    select {
        padding-right: 2.5em;
        option {
            color: $grey-dark;
            padding: 0.25em 0.5em;
        }
        option:disabled {
            cursor: not-allowed;
            opacity: 0.5;
        }
        optgroup {
            color: $grey-light;
            font-weight: $weight-normal;
            font-style: normal;
            padding: 0.25em 0;
        }
    }
    &.is-empty select {
        color: rgba($grey, 0.7);
    }

}