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<span class="srOnly">
    This is done by using the srOnly class.
</span>

.srOnly {
    border-width: 0;
    clip: rect(0, 0, 0, 0);
    height: 1px;
    margin: -1px;
    overflow: hidden;
    padding: 0;
    position: absolute;
    white-space: nowrap;
    width: 1px;
}