.custom-timer .timer {
    font-size: <?php echo esc_attr($atts['fontsize']); ?>px;
}

.custom-timer .timer-labels {
    display: flex;
    justify-content: space-between;
    font-size: <?php echo esc_attr($atts['fontsize'] - 4); ?>px;
    margin-top: 5px;
}

.custom-timer .hrs-label,
.custom-timer .min-label,
.custom-timer .sec-label {
    font-weight: bold;
}