调整wp\\u link\\u pages（）的“nextpagelink”和“previouspagelink”参数，使其具有可以设置样式的css类

$args = array(
    \'nextpagelink\'     => \'<span class="next">\' . __(\'Next page\') . \'</span>\',
    \'previouspagelink\' => \'<span class="prev">\' . __(\'Previous page\') . \'</span>\'
);
wp_link_pages($args);