syouzyou ha karui desu ga, kyou ha ie de yasumimasu.

They mark two different topics:

• 症状は軽いです = As for the symptoms, they are mild
• 今日は家で休みます = As for today, I’ll rest at home

The first は sets up 症状 as the topic of the first clause.
The second は sets up 今日 as the topic of the second clause.

This is very normal in Japanese. A sentence can shift topic partway through, especially when it has two clauses.

Here, が means but.

So:

• 症状は軽いですが = The symptoms are mild, but...

It connects the first idea to the second and shows a contrast:

• the symptoms are not severe
• but the speaker will still rest at home today

In polite Japanese, ending a clause with ですが is very common.

Because 軽い is an い-adjective.

With い-adjectives, you normally keep the adjective in its plain form and add です for politeness:

• 軽い = mild / light
• 軽いです = is mild

You do not say 軽くです.

軽く is the adverbial form, used when the adjective modifies a verb, such as:

• 軽く食べます = eat lightly / have a light meal

But here the adjective is directly describing 症状, so 軽いです is correct.

Because で marks the place where an action happens.

• 家で休みます = rest at home

The verb 休みます is an action/state that takes place somewhere, so で is natural.

Compare:

• 家にいます = be at home
• 家で休みます = rest at home

A simple way to think about it:

• に often marks a destination or location of existence
• で often marks the location where an action occurs

Here, 休みます means to rest.

So 家で休みます means:

• I’ll rest at home
• I’ll stay home and rest

Depending on context, 休みます can also mean:

• take a break
• take a day off
• be absent

In this sentence, because of 家で, the meaning is clearly rest at home.

Japanese often leaves out the subject when it is obvious from context.

So even though 私 is not stated, the sentence naturally implies something like:

• I’ll rest at home today

In conversation, Japanese usually omits words like I, you, or we unless they are needed for clarity or emphasis.

You can say 今日家で休みます, and it would still be understandable.

But 今日は gives today a stronger topic or contrastive feeling:

• As for today, I’ll rest at home
• Today, at least, I’m resting at home

This can imply something like:

• maybe not every day
• maybe even though the symptoms are mild, today I’ll still rest

So 今日は sounds a little more deliberate and natural in many contexts.

It can be either, depending on context.

Japanese nouns usually do not change form for singular vs. plural the way English nouns do. So 症状 could mean:

• a symptom
• symptoms

In this sentence, English would often translate it as the symptoms, but the Japanese word itself does not explicitly mark plurality.

It has two clauses joined by が:

1. 症状は軽いです
   = The symptoms are mild

2. 今日は家で休みます
   = Today I’ll rest at home

Together:

• 症状は軽いですが、今日は家で休みます。
• The symptoms are mild, but I’ll rest at home today.

So the pattern is:

• Topic + description + が
• Topic + place + で + verb

Yes. It is polite because it uses:

• です
• ます

Specifically:

• 軽いです
• 休みます

This makes it suitable for normal polite conversation, such as talking to a coworker, teacher, doctor, or someone you do not speak casually with.

A casual version would be something like:

• 症状は軽いけど、今日は家で休む。

No. Normal Japanese writing does not use spaces between words.

This sentence would usually be written as:

• 症状は軽いですが、今日は家で休みます。

Spaces are often added only in beginner materials to make the sentence easier to read.

Because in Japanese, 家 often means both:

• house as a physical building
• home as the place where you live

In 家で休みます, the natural English meaning is rest at home, not rest in the house, because the speaker is talking about where they will stay to recover.

So while 家 literally can mean house, home is the more natural translation here.