A convenção do condomínio e o regimento interno estão claros.

Because the subject is made of two nouns joined by e:

A convenção do condomínio + o regimento interno

That creates a compound subject, so the verb must be plural:

• está = singular
• estão = plural

So estão is the correct agreement form here.

Because the adjective is describing both nouns together:

• a convenção = feminine singular
• o regimento = masculine singular

When Portuguese has a mixed-gender plural group, the default agreement is masculine plural. So:

• feminine + masculine = claros
• not claras

If both nouns were feminine, then claras would be used.

Here, estar claros means that the documents are clear / understandable / explicit. Portuguese often uses estar to describe how something seems or how it is presented at the moment.

So estão claros suggests something like:

• they are clear
• they are understandable
• their wording is clear

You may also hear são claros in some contexts, but that sounds more like a general or inherent characteristic. In everyday usage, estão claros is very natural for talking about whether information, instructions, or rules are clear.

Yes, grammatically you could. But there is a slight nuance:

• estão claros = they are clear, understandable, well expressed
• são claros = they are clear by nature or in a more general/descriptive sense

In many real situations, Brazilians would prefer estão claros when talking about whether a text, rule, or explanation is clear to the reader.

Do is a contraction of:

• de
  • o = do

So:

• do condomínio = of the condominium / from the condominium

This kind of contraction is extremely common in Portuguese:

• de + a = da
• de + o = do
• em + a = na
• em + o = no

In Brazilian Portuguese, especially in housing or legal contexts, they are not exactly the same thing.

• convenção do condomínio: the condominium’s main governing document, similar to bylaws or a formal governing convention
• regimento interno: the internal rules or house rules, usually more about day-to-day behavior and procedures

So the sentence refers to two separate documents or sets of rules.

Portuguese usually uses definite articles with specific nouns more often than English does. Here, the sentence is talking about two specific documents:

• a convenção
• o regimento interno

Using the articles makes it sound natural and specific.

English often drops articles in places where Portuguese keeps them, so this is something English speakers need to get used to.

Because interno only agrees with regimento, which is singular masculine:

• o regimento interno

This is just a normal noun + adjective combination:

• regimento = masculine singular
• interno = masculine singular

Then later, the adjective claros describes the whole pair of nouns together, so that one becomes plural.

Grammatically, do condomínio is attached directly to convenção, but in context it is very likely understood to relate to both items.

So the sentence naturally suggests:

• the condominium convention
• the condominium internal regulations

If you wanted to make that explicit, you could also say:

A convenção e o regimento interno do condomínio estão claros.

That version is often very natural too.

Yes. That is a very natural alternative, especially if both items clearly belong to the same condominium.

Compare:

• A convenção do condomínio e o regimento interno estão claros.
• A convenção e o regimento interno do condomínio estão claros.

Both are acceptable. The second version groups both nouns more neatly under do condomínio.

No. Here claros means clear, easy to understand, or unambiguous.

The adjective claro can have different meanings depending on context:

• color: light
• explanation/text/rules: clear

In this sentence, it is clearly the second meaning.

A rough pronunciation for Brazilian Portuguese would be something like kon-ven-SOWN, with the final -ão nasalized.

A few important points:

• the stress falls on the last syllable: -ção
• -ão is a nasal sound, not a plain ow
• English speakers usually need practice with this nasal ending

The same kind of nasal sound appears in estão and condomínio has its own stress on -mí-: kon-do-MEE-nee-o.