How to Style the Number on a HTML List

:root {  font: 400 16px/1.25 Verdana}
ol {  list-style-type: none;}
ol li {  counter-increment: step-counter;  position: relative;  margin: 10px 0 0 0;}
ol li::before {  content: counter(step-counter);  display: block;  position: absolute;  top: -1px;  /* Adjust < -number | number+ > */  left: -32px;  width: 1.25rem;  height: 1.25rem;  line-height: 1.25rem;  background-color: rgb(0, 200, 200);  color: white;  font-weight: bold;  font-size: 0.8rem;  text-align: center;  border-radius: 15px;}

<ol>  <li>This is the first item</li>  <li>This is the second item</li>  <li>This is the third item</li>  <li>This is the fourth item</li>  <li>This is the fifth item</li>  <li>This is the sixth item</li></ol>

How to style the number on a html list?

It can be done using CSS3 but not 100% cross browser (namely IE7). using the pseudo :before element and counter-reset and counter-increment you can hide the list-style and create your own.

here is an article outlining how: Styling ordered list numbers

and here is a demo built from that article.

Also in case of the dreaded link rot - here is the main CSS code required (this can be applied to any ordered list)

ol {
    counter-reset:li; /* Initiate a counter */
    margin-left:0; /* Remove the default left margin */
    padding-left:0; /* Remove the default left padding */
}
ol > li {
    position:relative; /* Create a positioning context */
    margin:0 0 6px 2em; /* Give each list item a left margin to make room for the numbers */
    padding:4px 8px; /* Add some spacing around the content */
    list-style:none; /* Disable the normal item numbering */
    border-top:2px solid #666;
    background:#f6f6f6;
}
ol > li:before {
    content:counter(li); /* Use the counter as content */
    counter-increment:li; /* Increment the counter by 1 */
    /* Position and style the number */
    position:absolute;
    top:-2px;
    left:-2em;
    -moz-box-sizing:border-box;
    -webkit-box-sizing:border-box;
    box-sizing:border-box;
    width:2em;
    /* Some space between the number and the content in browsers that support
       generated content but not positioning it (Camino 2 is one example) */
    margin-right:8px;
    padding:4px;
    border-top:2px solid #666;
    color:#fff;
    background:#666;
    font-weight:bold;
    font-family:"Helvetica Neue", Arial, sans-serif;
    text-align:center;
}
li ol,
li ul {margin-top:6px;}
ol ol li:last-child {margin-bottom:0;}​

This code will produce a custom ordered list; albeit not the style you asked for. I will leave the customization work upto you :) cheers

Styling numbers of outside ordered list

Firstly, it's not list-position-style it's list-style-position. Anyway, just list-style: none; it so that to hide the numbers, then apply position: relative; to li and position: absolute; to its :before. Just take a look on what I have done below:

ol {   list-style: none;   counter-reset: item; } li {   counter-increment: item;   margin-bottom: 5px;    position: relative; } li:before {   margin-right: 10px;   content: counter(item);   background: lightblue;   border-radius: 100%;   color: white;   width: 1.2em;   text-align: center;   display: inline-block;   position: absolute;   left: -25px; }

<ol>   <li><span>blah blah blah.</span>   <ol type="a" class="ol substeps">   <li>blah blah</li>     <li>blah</li>     </ol></li>  <li>blah blah blah blah</li></ol>

document.querySelector('ol').children[1].classList.add('highlight');

li.highlight::marker {
  color: red;
}

<ol>
  <li>item</li>
  <li>item</li>
  <li>item</li>
  <li>item</li>
</ol>

.custom {  margin: 0;  padding: 0;  list-style-type: none;  counter-reset: step-counter calc(var(--start) - 1);}
.custom li {  counter-increment: step-counter;  margin-bottom: 10px;}
.custom li::before {  content: counter(step-counter);  margin-right: 5px;  font-size: 80%;  background-color: rgb(0, 200, 200);  color: white;  font-weight: bold;  padding: 3px 8px;  border-radius: 3px;}

<ol style="--start:6" start="6" class="custom">  <li>This is the sixth item</li>  <li>This is the seventh item</li>  <li>This is the eighth item</li>  <li>This is the ninth item</li>  <li>This is the tenth item</li></ol>

#thelistitem {
  color: blue;
}

#thelistitem::marker {
  color: var(--color);
}

<ol>
  <li id="thelistitem">
    Hello there!
  </li>
</ol>
<button onclick="document.getElementById('thelistitem').style.setProperty('--color', 'red');">Click me</button>

ol {  counter-reset: item;  margin-left: 0;  padding-left: 0;}li {  display: block;  margin-bottom: .5em;  margin-left: 2em;}li::before {  display: inline-block;  content: counter(item) ") ";  counter-increment: item;  width: 2em;  margin-left: -2em;}

<ol>  <li>One</li>  <li>Two</li>  <li>Three</li>  <li>Four</li>  <li>Five</li>  <li>Six</li>  <li>Seven</li>  <li>Eight</li>  <li>Nine<br>Items</li>  <li>Ten<br>Items</li></ol>