Новая грамматическая тема: частица «пусть» может выражать уступку, например: «Пусть макияж и простой, он ей очень подходит».

Here пусть does not mean let in the usual sense.

In this sentence, пусть is a particle of concession. It means something like:

• even if
• though
• granted that
• admittedly

So the pattern Пусть X и Y, Z means:

• Even if X is Y, Z
• Granted, X is Y, but Z

In Пусть макияж и простой, он ей очень подходит, the speaker is conceding one point first: yes, the makeup is simple. But despite that, it still suits her very well.

Here it is a particle, not a verb.

That matters because пусть has more than one use in Russian:

• пусть as a particle of concession
  
  • Пусть макияж и простой, он ей очень подходит.
• пусть in the sense of let / may
  
  • Пусть он войдёт. = Let him come in.
  • Пусть всё будет хорошо. = May everything be fine.

So learners often get confused because the same word appears in different functions. In your example, it is purely concessive: even though / granted that.

That и is part of a very common concessive pattern in Russian.

The structure is often:

• Пусть X и Y, ...
• Хотя X и Y, ...

Here, и does not simply mean and. It helps emphasize the concessive idea: even though X is indeed Y.

So:

• Пусть макияж и простой, он ей очень подходит means roughly:
• Granted that the makeup is simple, it still suits her very well

Without и, the sentence would usually sound less natural in this pattern.

Compare:

• Пусть он и молод, но очень опытен.
  = Though he is young, he is very experienced.

So in this construction, и is a normal and expected feature.

Because Russian normally omits the verb to be in the present tense.

So:

• макияж простой literally looks like makeup simple
• but it means the makeup is simple

This is completely normal Russian grammar.

Compare:

• Он врач. = He is a doctor.
• Она красивая. = She is beautiful.
• Макияж простой. = The makeup is simple.

So in the first clause, the implied meaning is:

• Пусть макияж и простой...
• Even though the makeup is simple...

Because it agrees with макияж.

Макияж is:

• masculine
• singular
• nominative

So the adjective must also be:

• masculine
• singular
• nominative

That gives простой.

Compare:

• макияж простой — masculine
• причёска простая — feminine
• платье простое — neuter
• туфли простые — plural

So if the noun changed, the adjective would change too:

• Пусть причёска и простая, она ей очень идёт.

Very close, yes.

You could also say:

• Хотя макияж и простой, он ей очень подходит.

This has almost the same meaning: Although the makeup is simple, it suits her very well.

The difference is mostly one of nuance:

• хотя = straightforward although
• пусть = granted / even if / admittedly

So пусть often sounds like the speaker is acknowledging an objection and then answering it.

That is why пусть can feel a little more rhetorical:

• Yes, it may be simple, but it still suits her.

Yes, absolutely.

You can say:

• Пусть макияж и простой, но он ей очень подходит.

That is perfectly natural.

In Russian, after a concessive clause, the main clause may appear:

• with но
• or without it

Both are possible.

Very roughly:

• without но = slightly smoother, more compact
• with но = the contrast is made more explicit

So both of these work:

• Пусть макияж и простой, он ей очень подходит.
• Пусть макияж и простой, но он ей очень подходит.

Because the sentence has two clauses:

1. Пусть макияж и простой
2. он ей очень подходит

The first clause is concessive, and the second is the main statement. Russian separates them with a comma.

This is similar to English punctuation in sentences like:

• Although the makeup is simple, it suits her very well.

So the comma is required because the sentence contains a subordinate concessive idea followed by the main clause.

Yes, but it can sound a bit more deliberate or rhetorical than the most basic хотя sentence.

A native speaker will understand it immediately, and it is perfectly normal Russian. But compared with plain хотя, пусть may sound:

• a bit more expressive
• a bit more argumentative
• sometimes a bit more literary or polished

For everyday speech, learners will often hear both:

• Хотя макияж и простой, он ей очень подходит
• Пусть макияж и простой, он ей очень подходит

The second one has more of a granted, but still... feeling.

Sometimes yes, but пусть is the safer choice here.

Пускай is often a more colloquial variant of пусть, especially in the let meaning:

• Пускай он войдёт.

In concessive uses, пусть is more standard and more common in careful speech and writing.

So for this grammar pattern, it is best for learners to remember:

• Пусть X и Y, ...

That is the clearest model to copy.