스크롤과 관련된 코드가 이미 존재함.

덮어쓸 필요가 있음

css > default.css

수정 전

<?php if (!empty($design['scrollbar_hidden']) && $design['scrollbar_hidden'] == '1'): ?>
/* 스크롤바 숨김 */
::-webkit-scrollbar {
    display: none;
}

* {
    -ms-overflow-style: none;  /* IE, Edge */
    scrollbar-width: none;  /* Firefox */
}
<?php else: ?>
/* 커스텀 스크롤바 */
::-webkit-scrollbar {
    width: <?php echo isset($design['scrollbar_width']) ? $design['scrollbar_width'] : '8'; ?>px;
    height: <?php echo isset($design['scrollbar_width']) ? $design['scrollbar_width'] : '8'; ?>px;
}

::-webkit-scrollbar-track {
    background: <?php echo isset($design['scrollbar_track_bg']) ? $design['scrollbar_track_bg'] : '#f1f5f9'; ?>;
    border-radius: <?php echo isset($design['scrollbar_track_radius']) ? $design['scrollbar_track_radius'] : '4'; ?>px;
}

::-webkit-scrollbar-thumb {
    background: <?php echo isset($design['scrollbar_thumb_bg']) ? $design['scrollbar_thumb_bg'] : '#94a3b8'; ?>;
    border-radius: <?php echo isset($design['scrollbar_thumb_radius']) ? $design['scrollbar_thumb_radius'] : '4'; ?>px;
}

::-webkit-scrollbar-thumb:hover {
    background: <?php echo isset($design['scrollbar_thumb_bg']) ? $design['scrollbar_thumb_bg'] : '#94a3b8'; ?>;
    filter: brightness(0.9);
}

/* Firefox 스크롤바 */
* {
    scrollbar-width: thin;
    scrollbar-color: <?php echo isset($design['scrollbar_thumb_bg']) ? $design['scrollbar_thumb_bg'] : '#94a3b8'; ?> <?php echo isset($design['scrollbar_track_bg']) ? $design['scrollbar_track_bg'] : '#f1f5f9'; ?>;
}
<?php endif; ?>

::-webkit-scrollbar {
    display: none !important;
}

* {
    -ms-overflow-style: none !important;
    scrollbar-width: none !important; 
}


body {
    -ms-overflow-style: none !important;
    scrollbar-width: none !important;
}
body::-webkit-scrollbar {
    display: none !important;
}