Poslije kiše park izgleda još ljepše.

Because poslije (after) requires the genitive case.

• dictionary form: kiša = rain
• after poslije: kiše = of rain / after rain

So:

• poslije kiše = after the rain / after rain

This is very common in Croatian: certain prepositions automatically trigger a specific case, and poslije takes the genitive.

Yes. Nakon kiše is also correct and means the same thing: after the rain.

In many contexts, poslije and nakon are interchangeable. A learner can safely understand both. Very roughly:

• poslije is often felt as a bit more everyday/conversational
• nakon can sound a bit more neutral or formal

But both are standard and natural here.

Izgleda is the 3rd person singular present of izgledati.

So:

• izgledam = I look / appear
• izgledaš = you look
• izgleda = he/she/it looks

In this sentence:

• park izgleda = the park looks

It describes appearance, not the act of looking at something.

Because park is the subject of the sentence, so it is in the nominative case.

The basic structure is:

• Poslije kiše = after the rain
• park = the park
• izgleda još ljepše = looks even nicer

Since park is the thing doing the “looking/appearing,” it stays in its basic form.

Here još means even.

So:

• ljepše = more beautifully / nicer
• još ljepše = even more beautifully / even nicer

In English, the most natural translation is usually even nicer.

Be careful, because još can mean different things in other contexts, such as:

• still
• yet
• more

But with a comparative like ljepše, it very often means even.

This sentence uses ljepše in the common adverbial/predicative way after izgledati.

Croatian often says:

• izgleda lijepo
• izgleda bolje
• izgleda čudno
• izgleda ljepše

So here ljepše works like nicer / more nicely in appearance, and it does not have to agree with park as a regular adjective would.

A useful comparison:

• Park izgleda još ljepše. = The park looks even nicer.
• Park je još ljepši. = The park is even nicer.

In the second sentence, ljepši agrees with park because it is a straightforward adjective with biti (to be).

It comes from the comparative of lijep (beautiful, nice).

The forms are:

• lijep = beautiful, nice
• ljepši = more beautiful, nicer
• ljepše = more beautifully / nicer (in this kind of use)

Notice the stem change:

• lijep → ljep-

This is a normal pattern for this word, even though it may look a bit irregular to an English speaker.

So in this sentence:

• još ljepše = even nicer

Yes, you could. Croatian word order is fairly flexible.

These are both natural:

• Poslije kiše park izgleda još ljepše.
• Park poslije kiše izgleda još ljepše.

The first version puts poslije kiše first, which gives a nice sense of setting the scene: After the rain, ...

The second starts with park, so it puts the focus more immediately on the park.

The meaning stays basically the same.

Usually, no.

In Croatian, a short introductory phrase like Poslije kiše does not normally need a comma:

• Poslije kiše park izgleda još ljepše.

You might sometimes see a comma for stylistic emphasis, but in ordinary writing it is not necessary.

A rough English-friendly guide:

• kiše sounds roughly like KEE-sheh
• ljepše sounds roughly like LYEP-sheh

A few useful details:

• š is like English sh
• lj is a single Croatian sound, something like the lli in some pronunciations of million, though not exactly the same
• final e is clearly pronounced, not silent

So:

• kiše → KEE-sheh
• ljepše → LYEP-sheh

Yes, that is a perfectly natural English translation if the context allows it.

Literally, ljepše is closer to more beautifully / prettier / nicer, but English often prefers a smoother translation such as:

• The park looks even nicer after the rain.
• After the rain, the park looks even more beautiful.
• The park looks better after the rain.

So better is not word-for-word, but it can still be a very natural translation.