Hi Richard,
Sure, please add this CSS to Theme Options > CSS with your preferred font size.
.single-post #reply-title {
font-size: 1em !important;
}
As for translation, I see that you’re not using multiple language so translating it this way should be okay. Please add this code to your child theme’s functions.php
add_filter( 'gettext', 'custom_string_translation', 20, 3 );
function custom_string_translation( $translated_text, $text, $domain ) {
if ( is_singular() ) {
switch ( trim( $translated_text ) ) {
case 'Reply' :
$translated_text = __( 'Répondre à Inacio', '__x__' );
break;
case 'Comments' :
$translated_text = __( 'Répondre à Inacio', '__x__' );
break;
}
}
return $translated_text;
}
And please add your translation
Hope this helps.