i use the education hub theme (premium version) and wanna modify the image size of the sliders. i noticed that i can go to admin panel > appearance > customize > additional css and paste the codes there but after i clicked the publish button, a message shows that “looks like something’s gone wrong. wait a couple seconds, and then try again”. may i know if i forget to add some codes? below please see the css

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div#main-slider {
height: 600px !important;
width: 800px !important;
}

/* if used slider, each page will display the featured image first, this css hide the image in each page */
.page img.aligncenter.wp-post-image {
display: none;
}

/* adjust the font size of the page title */
h1 {
font-size: 38px;
}

/* hide the page title */
.page h1.entry-title {
display: none;
}

/* hide the prev/next in post*/
nav.navigation.post-navigation {
display: none;
}

/* hide featured content */
#featured-content p {
display: none;
}

/* if used slider, each page will display the featured image first, this css hide the image in each page */
.page img.aligncenter.wp-post-image {
display: none;
}

/* adjust the font size of the page title */
h1 {
font-size: 38px;
}

/* hide the page title */
.page h1.entry-title {
display: none;
}

/* hide the prev/next in post*/
nav.navigation.post-navigation {
display: none;
}

/* hide featured content */
#featured-content p {
display: none;
}

#featured-content a img {
pointer-events: none;
}

/* hide the author name and date */
/*.entry-meta {
display: none;
}*/

/* hide entry footer */
/*
.entry-footer {
display: none;
}
*/

/* the following 3 entries are used to adjust the length of notice, NOT recommeded, uncommented them if want to use. */
/*
#quick-contact {
width: 100%;
}

.top-news {
width: 60%;
}

#notice-ticker {
width: 90%;
}
*/
/* end of the entries */
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