How to make a submenu the entire width of the container?

Question

css

Good afternoon. Can you please tell me how to make a horizontal submenu the entire width of the container?

Tried to solve this problem with

.dropdown-menu {
  width: 100%;
  max-width: 1140px;
text-align: center;
left: 0%;
right: 0%;
top: auto;
position: fixed;
margin: 0 auto;
}

Looks like that. as it should, but because of the fixation, the menu suffers if it is slightly scrolled.

The submenu will have 4-5 columns.

I understand that it is necessary to work with this part of the code, but I have already tried everything ...

<div class="dropdown-menu">
            <div class="dropdown-inner">
              <?php foreach (array_chunk($category['children'], ceil(count($category['children']) / $category['column'])) as $children) { ?>
              <ul class="list-unstyled">
                <?php foreach ($children as $child) { ?>
                <li class="drop-dva"><a href="<?php echo $child['href']; ?>"><?php echo $child['name']; ?></a></li>
                <?php } ?>
              </ul>
              <?php } ?>
            </div>
             </div>

I do on a standard template ocstore 2.3

Answer 1

First things first: left: 0% overlaps right: 0%, a redundant property.
Second, an example:

<!-- Условный родительский контейнер .container -->
<div class="container">
    <!-- Список с элементами меню ul -->
    <ul>
        <li>
            <a href="#">Ссылка 1</a>
        </li>
        <li>
            <a href="#">Ссылка 2</a>
        </li>
        <li>
            <a href="#">Ссылка 3</a>
        </li>
    </ul>
</div>

<style>
    .container ul {
        display: block;
        height: 60px;
        line-height: 60px;
        background: #ededed;
    }
    .container ul li {
        display: inline-block;
        list-style-type: none;
        padding: 0 20px;
    }
</style>

Third, your question seems to me to have very little input, so the answer is partly based on guesswork as to what is required.