primevue-mirror/src/components/button/Button.css

/* Button */
.p-button {
    display: inline-block;
    position: relative;
    padding: 0;
    text-decoration: none !important;
    cursor: pointer;
    text-align: center;
    zoom: 1;
    overflow: visible; /* the overflow property removes extra width in IE */
    margin-right: 0.25em;
    user-select: none;
    -moz-user-select: none;
    -webkit-user-select: none;
}

.p-button:disabled {
    cursor: default;
}

/*button text element */
.p-button .p-button-text {
    display: block;
    line-height: normal;
}

.p-button-text-only .p-button-text {
    padding: .25em 1em;
}

.p-button-icon-only .p-button-text,
.p-button-text-empty .p-button-text {
    padding: .25em;
    text-indent: -9999999px;
}

.p-button-text-icon-left .p-button-text {
    padding: .25em 1em .25em 2.1em;
}

.p-button-text-icon-right .p-button-text {
    padding: .25em 2.1em .25em 1em;
}

/*button icon element(s) */
.p-button-icon-only .p-button-icon-left,
.p-button-text-icon-left .p-button-icon-left,
.p-button-text-icon-right .p-button-icon-right {
    position: absolute;
    top: 50%;
    margin-top: -.5em;
    height: 1em;
}

.p-button-icon-only .p-button-icon-left {
    top: 50%;
    left: 50%;
    margin-top: -.5em;
    margin-left: -.5em;
    width: 1em;
    height: 1em;
}

.p-button-icon-left {
    left: .5em;
}

.p-button-icon-right {
    right: .5em;
}

/*button sets*/
.p-buttonset .p-button {
    margin-left: 0;
    margin-right: 0;
}

/* workarounds */
button.p-button::-moz-focus-inner {
    border: 0; padding: 0; /* reset extra padding in Firefox */
}

/** Fluid **/
.p-fluid .p-button {
    width: 100%;
}

.p-fluid .p-button-text-icon-left .p-button-text,
.p-fluid .p-button-text-icon-right .p-button-text {
    padding-left: 1em;
    padding-right: 1em;
}

/** ButtonSet **/
.p-fluid .p-buttonset {
    width: 100%;
}

.p-fluid .p-buttonset.p-buttonset-1 .p-button {width: 100%;}
.p-fluid .p-buttonset.p-buttonset-2 .p-button {width: 50%;}
.p-fluid .p-buttonset.p-buttonset-3 .p-button {width: 33.3%;}
.p-fluid .p-buttonset.p-buttonset-4 .p-button {width: 25%;}
.p-fluid .p-buttonset.p-buttonset-5 .p-button {width: 20%;}
.p-fluid .p-buttonset.p-buttonset-6 .p-button {width: 16.6%;}

@media (max-width: 640px) {
    .p-fluid .p-buttonset.p-buttonset-1 .p-button,
    .p-fluid .p-buttonset.p-buttonset-2 .p-button,
    .p-fluid .p-buttonset.p-buttonset-3 .p-button,
    .p-fluid .p-buttonset.p-buttonset-4 .p-button,
    .p-fluid .p-buttonset.p-buttonset-5 .p-button,
    .p-fluid .p-buttonset.p-buttonset-6 .p-button {
        width: 100%;
    }
}