Cara Insert CSS Berbeda-beda di Blogspot

Could you please provide more information on what you are attempting to do as this will help your fellow bloggers in the community to better assist you.

Using Theme > Customize > Advanced  > Add CSS, you can add your custom  CSS code.

If you need to add a print only CSS, you can use a print rule to enclose the print only CSS.

@media only print {
/* Your print only CSS goes here */
}

If you need CSS for mobile devices, you can try the following CSS media queries:

/* Extra small devices (phones, 600px and down) */
@media only screen and (max-width: 600px) {
/* Your CSS goes here */
}

/* Small devices (portrait tablets and large phones, 600px and up) */
@media only screen and (min-width: 600px) {
/* Your CSS goes here */
}

/* Medium devices (landscape tablets, 768px and up) */
@media only screen and (min-width: 768px) {
/* Your CSS goes here */
}

/* Large devices (laptops/desktops, 992px and up) */
@media only screen and (min-width: 992px) {
/* Your CSS goes here */
}

/* Extra large devices (large laptops and desktops, 1200px and up) */
@media only screen and (min-width: 1200px) {
/* Your CSS goes here */
}

Additional information on CSS media queries is available here:
https://www.w3schools.com/cssref/css3_pr_mediaquery.asp
https://www.w3schools.com/css/css_rwd_mediaqueries.asp

If you need a specific CSS code for one post or one page, you can insert CSS code on the relevant post or page by selecting the HTML mode in the Blogger editor:

<style type="text/css">
/* Your page or post specific CSS goes here */
</style>

​I hope this helps you understand the possibilities.

Have a good day.