I am creating wordpress theme on a single options page. I have customized the default do_setting_fields and do_setting_sections functions. my fields are displaying fine but when i am trying to save it, It won't save.

function amna_theme_options_page () {
wp_enqueue_style( 'theme-options-css', get_template_directory_uri() . '/inc/admin/assets/css/theme-options-css.css' );
settings_errors(); 
?>
<div class="wrap flex-tab">
    <form action='' method='post' class="amna-fields">
        <?php 
        amna_do_settings_fields('amna-fields-group', 'theme_amna');
        amna_do_settings_sections('theme_amna'); 
        
        submit_button();
        ?>
    </form>
</div>
<?php }

And these are the functions i have override to display fields

function amna_do_settings_sections($page) {
global $wp_settings_sections, $wp_settings_fields;

if ( !isset($wp_settings_sections) || !isset($wp_settings_sections[$page]) )
    return;

foreach( (array) $wp_settings_sections[$page] as $section ) {
    echo "<h3>{$section['title']}</h3>\n";
    call_user_func($section['callback'], $section);
    if ( !isset($wp_settings_fields) ||
         !isset($wp_settings_fields[$page]) ||
         !isset($wp_settings_fields[$page][$section['id']]) )
            continue;
    echo '<div class="settings-form-wrapper">';
    amna_do_settings_fields($page, $section['id']);
    echo '</div>';
}
}

function amna_do_settings_fields($page, $section) {
global $wp_settings_fields;

if ( ! isset( $wp_settings_fields[ $page ][ $section ] ) ) {
    return;
}

foreach ( (array) $wp_settings_fields[$page][$section] as $field ) { ?>
    <div class="settings-form-row flex-tab">
        
        <?php if ( !empty($field['args']['label_for']) )
            echo '<p><label for="' . $field['args']['label_for'] . '">' .
                $field['title'] . '</label><br />';
        else
        call_user_func($field['callback'], $field['args']);
        echo '</p>';
    echo '</div>';
}
}

I am creating wordpress theme on a single options page. I have customized the default do_settings_fields and do_settings_sections functions. my fields are displaying fine but when i am trying to save it, It won't save.

function amna_theme_options_page () {
wp_enqueue_style( 'theme-options-css', get_template_directory_uri() . '/inc/admin/assets/css/theme-options-css.css' );
settings_errors(); 
?>
<div class="wrap flex-tab">
    <form action='' method='post' class="amna-fields">
        <?php 
        amna_do_settings_fields('amna-fields-group', 'theme_amna');
        amna_do_settings_sections('theme_amna'); 
        
        submit_button();
        ?>
    </form>
</div>
<?php }

And these are the functions i have override to display fields

function amna_do_settings_sections($page) {
global $wp_settings_sections, $wp_settings_fields;

if ( !isset($wp_settings_sections) || !isset($wp_settings_sections[$page]) )
    return;

foreach( (array) $wp_settings_sections[$page] as $section ) {
    echo "<h3>{$section['title']}</h3>\n";
    call_user_func($section['callback'], $section);
    if ( !isset($wp_settings_fields) ||
         !isset($wp_settings_fields[$page]) ||
         !isset($wp_settings_fields[$page][$section['id']]) )
            continue;
    echo '<div class="settings-form-wrapper">';
    amna_do_settings_fields($page, $section['id']);
    echo '</div>';
}
}

function amna_do_settings_fields($page, $section) {
global $wp_settings_fields;

if ( ! isset( $wp_settings_fields[ $page ][ $section ] ) ) {
    return;
}

foreach ( (array) $wp_settings_fields[$page][$section] as $field ) { ?>
    <div class="settings-form-row flex-tab">
        
        <?php if ( !empty($field['args']['label_for']) )
            echo '<p><label for="' . $field['args']['label_for'] . '">' .
                $field['title'] . '</label><br />';
        else
        call_user_func($field['callback'], $field['args']);
        echo '</p>';
    echo '</div>';
}
}