Frost_edelweiss

Yes, it is a light hearted humming while she is rummaging to find clothes for Jiaxu who is stuck in hospital. It is not one of the 7 OST songs. I wonder if it could be a yihuik song...
No time to trawl through the yihuik song compilation MV; though, and it could be another playlist. The tune rings familiar but I can't place it right now.
I did find one song that was from a different OST. It's the Zhāng Yīháo (張洢豪) song : 遇见你的第一天起我就喜欢你 I've Liked You Since The First Day I Met You, from the c-drama 《时光与他，恰是正好 》Time and Him are Just Right OST
This song is featured in ep 12 when student Jiang Ming goes to the stage to sing and play it on the guitar, as a confesion to Sang Zhi who is already leaving and does not listen.
(Such a shame that we are deprived of Discussion pins to collect these infos :( )

yes, I saw that too. For once, I have reacted harshly here against such haters. I don't usually let myself get involved in controversies and play the sjw for the wronged ones. I prefer moderate tones...

Yeah... Smiles...

They are not post credits but overlooked by hasty watchers who run away to next episode when they reach a few still pictures.
Check my postings in Episode Guide to find why and where these are "added"...

It would be nice if we were not deprived of a Discussion option to pin "Hidden details in the drama", "Positive reviews (haters abstain)" and "Music featured in HL"....
I suspect we can't because of the reality of the haters "water army" even on MDL :(

Thanks! I too prefer positive comments to general demolishing and nitpicking when it is clear, as ratings not only here but elsewhere show, that this one is a VERY GOOD and even EXCEPTIONALLY GOOD drama, and that the actress is indeed talented and deserving of praise.
Even for non keluli, it is worth it to go check out these threads : you are right.

I don't do social media generally (have no need for an army of friends, although am willing to greet some people that interacted here in conversations; and despite I don't shake off followers who are not put off by my not answering friend requests),
but I will keep these links in my personal file about what I watch, read, or listen to!
Continued happy drama watching good wishes to you.

This one is in the 7 OST songs I mentioned.

bgm has been asked about several times, Emmaline Zhang wrote :"I bought them on itunes apple.. and also available on spotify" But I don't use itunes and spotify so can't check if she meant the songs or really the instrumental bgm.
I noticed someone spotted Sang Yan humming or singing a snippet of a Coco Lee song, (It was her famous DiDaDee song).

It is unfortunate that we are deprived of a Discussion pin for posting what we know about the music, or the settings and shooting locales.

I have decided to abstain from listening to that mantis' often toxic rants filled with half baked notions that she dishonestly just copy pastes from toxic hater social media when she finds it. Not just for ZLS whom she clearly dislikes but also about most other young successful actors. She deigns to be less poisonous in the case of some lesser known or older well known ones, but even there, I don't trust her advise any longer.
The only ones I more or less listen to are Marcus an CdramaInvasion. But I prefer to follow my gut feeling, because even recoms from some I suspected were thinking along same lines as I do, have not always brought me to watch stuff I enjoyed. Perhaps I am quirky. Anyway, I don"t purport to set up a channel with my recoms.
I once added a list in FB but to me, now, even reviewing is a chore. I just keep tabs on what I watch for myself and am not trying to spread the "good gospel" to everybody... It's bad enough that I indulge in adding comments here.
I prefer adding facts, about settings, music, places, historical details, when I feel like it, now in Discussion, if there is a feature for it (don't know why there isn't for this drama. Although I suspect it has to do with the toxic water army targeting Rosy.
See what that "reviewer" most certainly made us be amputated of ?
Now we have to trawl through thousands of comments to find those about music we might be interested in.

Very nice and heartfelt appreciation of the drama. I also liked the post scriptum " If you’re a male who enjoyed Hidden Love as much as I did, do know you that you are amazing. Thank you for being so willing to understand a girl’s heart."
But surely crushes are not only a female thing.
We did witness young Fu's crush for young Zhi... and Jiang Ming's later.
Of course, these crushes are rather conventionally heterosexual, but they could also happen in same sex relationships. In the manhua, it is even spelled out that probably, since he's been without a gf for that many years, Jiaxu must be in love with Sang Yan!
Yet, bromances and sistermances are not necessarily sexual : it can just be a warm friendship, like the ones portrayed in this sweet and very real-feeling c-drama.
Although the characters are more "ideal" than they could be in real life: no one is as perfectly dedicated as Sang Zhi, nor as gentle as Jiaxu, sigh. If there were such people, the world would be a better place. The misunderstandings they go through to doubt each other are often just the truth, in real life, and disappointments have to be dealt with.
Btw the wise advice that Jiaxu gave to Zhi, to send unwanted suitors packing, resonated with me. "Thank you for your care about me. But I have already someone else in my heart."and let the other initiate if they still hoped we could stay just friends. That rang so true: it is the kindest way do it,even if there is no one else really.
This lovely drama is packed with sound advice like that, plus incentives to not let go totally of oneself and end up obsessed and mentally ill like the Jiang Ying character or led to betray and become evil like the Xin Zhenru classmate.

I was going back to check on some songs that were featured in the drama. I already had pointed out Drowninng Sorrows by Mao Buyi in ep.8 You can listen to the full song here with full Chinese, pinyin and English translation in this MV : https://www.youtube.com/watch?v=A3M4Zm2s1Ao

But there was another one that sounded familiar to me, the one Jiang Ming was singing for Zhi in ep.12. This one was in fact :
遇见你的第一天起我就喜欢你 I've Liked You Since The First Day I Met You, from the c-drama 《时光与他，恰是正好 》Time and Him are Just Right OST, sung by Zhāng Yīháo (張洢豪)
(I'll add it to my review, in the paragraph list of the songs that were played in HL.)
For a full performance with Chinese and pinyin lyrics, there is this MV : https://www.youtube.com/watch?v=LTH4dD1lYdI

Peachey Blossom and some others have provides MV compilations for the 7 songs in the OST :
https://www.youtube.com/watch?v=sljE9-lAe8Y&t=1121s
Titles; singers and timestamps are in the description of that MV, and if you need the pinyin and translations, you can look for the individual titles in the Peachy Blossom channel.

(I wanted to add this in Discussion as " OST songs and other music from HIDDEN LOVE "
Feel free to add more there, if you noticed other songs and music you recognized !
but hmm where is the button to add a discussion ?)

Forget all that you watched, get rid of the jaded gazing through heavily lead-tinted dark old-hand "grandma- who- knows- better" glasses of disbelief and suspicion. (Btw chuckle along when you get to the part with the monstrous and hilarious asymmetrical sunglasses).
Even if this doesn't remind you of the crushes you might have had, treasured or awkward suppressed and forgotten childish memories, it could let you be moved or reminded of what it felt like to imagine and get the added bonus of personal connection to the youth and coming-of-age story better than anything you watched before.
I suggest you watch on just as if you were admiring and expecting a small seedling break the soil and grow first frail then strong until the rose bud flowers and engulfs you in its heavenly perfume : enjoy !
This drama is very special and we are many who knew it even from the beginning with the too young child actress who was not bad but did not steal or represent the show.
Zhao Lusi and Chen Zheyuan have elevated the "classical love story" from ordinary to work of art : it is that good!
That's why it is on top of the wave of popularity, not just a little story for fangirls of a manhua. Netflix does not look to China to purchase a drama idly. It is already an international phenomenon, breaking many mental and geographical boundaries with its soft and refreshing, healing message, based on humanity's most powerful sentiments to change the world for the better : hope, confidence, benevolence, trust, courage, persistence, and love.
Also, don't forget to play along with the end snippets and find clues to where they belong and why they were added.
:)

Better than that lol. For me it's a straight 11 !!

Or, if you can't access that for some reason, try kiss or cool or similar.
Or patiently wait for later.

Ep25? yes, it is a common complaint from those who watched the episode, alas.
Perhaps they will get fixed later, or Netflix will have better ones.
Viki doesn't have the drama, unfortunately, so the dedicated fansubbers will not be able to enlighten us about some moments that had us raise eyebrows.
It does not detract from the fact that the acting and story was excellent.

Amending my answer.
After some thought, while rewatching Ep25, I think the message on that faded star strip must have been something like:
我的梦想就是去宜荷大学 (wǒ de mèngxiǎng jiùshì qù yi hé dàxué)
My dream is to go to Yihé university.
I first thought it was 鱼河 Yúhé (fish river) but of course it was 宜荷 Yihé in subtitles

Enough netting fish on this Net for now ! Another day is dawning, another drama beckoning (Yang Yang Fireworks next after finishing with the Bai Jingting Destined ; and then, forging ahead with the Longest Promise... Too much that's tempting).

Watch till very end of 25.5 and see the message :
只只的 所有的 愿望 成真 (Zhǐ zhǐ de suǒyǒu de yuànwàng chéng zhēn)
May ZhiZhi's wishes come true

So sweet, and all our wishes came true too !

I will be looking forward for that Snowstorm of Love !

Yes, no wait for fast track option, but a treat and an add-on 25.5 with lots of stuff including the explanation for the somewhat cryptic message on the last star at the end of episode 25.
It read : 只只的 所有的 愿望 成真 (Zhǐ zhǐ de suǒyǒu de yuànwàng chéng zhēn)
May ZhiZhi's wishes all come true !
And ours did as well - glowing heart for this lovely drama !

Ah yes :
只只的 所有的 愿望 成真 (Zhǐ zhǐ de suǒyǒu de yuànwàng chéng zhēn)
May ZhiZhi's wishes all come true.
Sweet.