Can't change one specific div in a list ?

Question

Hello,

I have a list of several div (10).
i gave them the exact same configuration with a class.
And then proceded to give each one a unique id.

Now my problem is that everything works until i try to select one of the div and change it with CSS.

here's the html part :

<div id='menu'>
<div id="firstlist">
<ul>
<li><div id='1b' class='ch'></div></li>
<li><div id='2b' class='ch'></div></li>
<li><div id='3b' class='ch'></div></li>
<li><div id='4b' class='ch'></div></li>
<li><div id='5b' class='ch'></div></li>
</ul>
</div>
<div id='secondlist'>
<ul>
<li><div id='6b' class='ch'></div></li>
<li><div id='7b' class='ch'></div></li>
<li><div id='8b' class='ch'></div></li>
<li><div id='9b' class='ch'></div></li>
<li><div id='10b' class='ch'></div></li>
</ul>
</div>
</div>

And here's the CSS part :

#1b{
background-color: red;
}
#menu{
display: flex;
}

#menu ul{
display: flex;
flex-direction: column;
}

.ch{
border: 1px solid black;
border-radius: 100%;
height: 60px;
width: 60px;
transition-duration: 0.5s;
list-style: none;
margin: 8px;
}

.ch:hover{
transition-duration: 0.5s;
width: 70px;
height: 70px;
}

.ch:active{
transition-duration: 0.5s;
border-bottom-color: red;
}

a HUGE thanks to anyone that can help !!!
Have a great day !

Answer 1

The problem seems to be that the id should no start with a digit…

Html: <div id=b1>Text</div>
Css: #b1{…}
^^Worked for me
While it did not work with id 1b

Answer 2

What do you want to change?

People are more likely to help if you provide a minimal working example as a script on sololearn playground. Goo Code section, click +, select the programming language, insert your code and save. Come back to this thread, click +, Insert Code, sort for My Code Bits, select your code.

Answer 3

Thanks a lot, didn't even thought about that 😅🤦‍♂️.
Have a Great day/night 😉👍

Answer 4

What Alexander Thiem said, and from the CSS course on Sololearn:

"To select elements with a specific class, use a period character, followed by the name of the class.
Do NOT start a class or id name with a number!"

Answer 5

ID's Cannot Start With a Number