How can I adapt the menu bar and content using ready-made styles?

I tried to adapt the menu bar and content using ready-made styles.

And then I try to add some content from a known set of ready-made styles.

I try to add several elements
but they overlap or remove each other’s style or elements.

How can I make the navigation bar separately independent and be able to add content elements from a known set of ready-made styles without damaging the navigation bar and themselves?

How can I adapt the menu bar and content using ready-made styles?

I would like, if possible, to try to somehow integrate the menu bar into the style system. I’m still a beginner.

I mainly do logic in Django, and for the interface, blocks are something similar to fomantic-ui.com – ready-made style systems.

Now I’m trying to add a menu bar different from the style (“fomantic-ui.com”) – but it doesn’t work the same as without the style system (“fomantic-ui.com”).
It overlaps the content and the style seems to be mixed.

I’m trying to create a Django . HTML design from the navigation bar made by hand and the rest of the content to design based on ready-made styles – fomantic-ui.com.

index.html

{% load static %}
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Sidebar Menu | Side Navigation Bar</title>
    <!-- CSS -->
    <link rel="stylesheet" href="{% static "css/style.css" %}" />
    <!-- Boxicons CSS -->
    <link
      href="https://unpkg.com/[email protected]/css/boxicons.min.css"
      rel="stylesheet"
    />
    <!-- You MUST include jQuery 3.4+ before Fomantic -->
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/jquery.min.js"></script>
    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/[email protected]/dist/semantic.min.css">
    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/semantic.min.js"></script>
  </head>
  <body hx-headers='{"X-CSRFToken": "{{ csrf_token }}"}'>
    <nav>
      <div class="logo">
        <i class="bx bx-menu menu-icon"></i>
        <span class="logo-name">InfoEco</span>
      </div>
      <div class="sidebar">
        <div class="logo">
          <i class="bx bx-menu menu-icon"></i>
          <span class="logo-name">InfoEco</span>
        </div>
        <div class="sidebar-content">
          <ul class="lists">
            <li class="list">
              <a href="#" class="nav-link">
                <i class="bx bx-home-alt icon"></i>
                <span class="link">Home</span>
              </a>
            </li>
            <li class="list">
              <a href="#" class="nav-link">
                <i class="bx bx-bar-chart-alt-2 icon"></i>
                <span class="link">Label Nav Menu 1</span>
              </a>
              <div class="sub-menu">
                <a href="#">Label Nav Sub Menu 1</a>
                <a href="#">Label Nav Sub Menu 2</a>
                <a href="#">Label Nav Sub Menu 3</a>
                <a href="#">Label Nav Sub Menu 4</a>
              </div>
            </li>
            <li class="list">
              <a href="#" class="nav-link">
                <i class="bx bx-bell icon"></i>
                <span class="link">Label Nav Menu 2</span>
              </a>
              <div class="sub-menu">
                <a href="#">Label Nav Sub Menu 1</a>
                <a href="#">Label Nav Sub Menu 2</a>
              </div>
            </li>
            <li class="list">
              <a href="#" class="nav-link">
                <i class="bx bx-heart icon"></i>
                <span class="link">Label Nav Menu 3</span>
              </a>
            </li>
            <li class="list">
              <a href="#" class="nav-link">
                <i class="bx bx-folder-open icon"></i>
                <span class="link">Label Nav Menu 4</span>
              </a>
            </li>
          </ul>

          <div class="bottom-cotent">
            <li class="list">
              <a href="#" class="nav-link">
                <i class="bx bx-cog icon"></i>
                <span class="link">Label Nav Menu 5</span>
              </a>
            </li>
            <li class="list">
              <a href="#" class="nav-link">
                <i class="bx bx-log-out icon"></i>
                <span class="link">Label Nav Menu 6</span>
              </a>
            </li>
          </div>
        </div>
      </div>
    </nav>

    <section class="overlay"></section> 
    
    <div class="ui container">
      <div class="ui grid">
        <div class="four wide column">
          <div class="ui vertical menu">
            <a class="item">
              <h4 class="ui header">Promotions</h4>
              <p>Check out our new promotions</p>
            </a>
            <a class="item">
              <h4 class="ui header">Coupons</h4>
              <p>Check out our collection of coupons</p>
            </a>
            <a class="item">
              <h4 class="ui header">Rebates</h4>
              <p>Visit our rebate forum for information on claiming rebates</p>
            </a>
          </div>
        </div>
        <div class="twelve wide column">content</div>
      </div>
    </div>
    <script src="{% static "script/script.js" %}"></script>
  </body>
</html>

style.css

/* Google Fonts - Poppins */
@import url("https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600&display=swap");

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
}
body {
  min-height: 100%;
  background: #e3f2fd;
}
nav {
  position: fixed;
  top: 0;
  left: 0;
  height: 70px;
  width: 100%;
  display: flex;
  align-items: center;
  background: #fff;
  box-shadow: 0 0 1px rgba(0, 0, 0, 0.1);
}
nav .logo {
  display: flex;
  align-items: center;
  margin: 0 24px;
}
.logo .menu-icon {
  color: #333;
  font-size: 24px;
  margin-right: 14px;
  cursor: pointer;
}
.logo .logo-name {
  color: #333;
  font-size: 22px;
  font-weight: 500;
}
nav .sidebar {
  position: fixed;
  top: 0;
  left: -100%;
  height: 100%;
  width: 260px;
  padding: 20px 0;
  background-color: #fff;
  box-shadow: 0 5px 1px rgba(0, 0, 0, 0.1);
  transition: all 0.4s ease;
}
nav.open .sidebar {
  left: 0;
}
.sidebar .sidebar-content {
  display: flex;
  height: 100%;
  flex-direction: column;
  justify-content: space-between;
  padding: 30px 16px;
}
.sidebar-content .list {
  list-style: none;
}
.list .nav-link {
  display: flex;
  align-items: center;
  margin: 8px 0;
  padding: 14px 12px;
  border-radius: 8px;
  text-decoration: none;
}
.lists .nav-link:hover {
  background: linear-gradient(#dfe4e6, #eff2f4);
}
.nav-link .icon {
  margin-right: 14px;
  font-size: 20px;
  color: #707070;
}
.nav-link .link {
  font-size: 16px;
  color: #707070;
  font-weight: 400;
}
.lists .nav-link:hover .icon,
.lists .nav-link:hover .link {
  color: #4b6a78;
  font-weight: 500;
}
.overlay {
  position: fixed;
  top: 0;
  left: -100%;
  height: 1000vh;
  width: 200%;
  opacity: 0;
  pointer-events: none;
  transition: all 0.4s ease;
  background: rgba(0, 0, 0, 0.3);
}
nav.open ~ .overlay {
  opacity: 1;
  left: 260px;
  pointer-events: auto;
}
nav .sidebar .sidebar-content .list .sub-menu {
  margin-left: 5px;
  padding-left: 10px;
  border-left: 1px solid #bbb;
  max-height: 0px;
  overflow: hidden;
  transition: max-height 300ms ease-in-out;
}
nav .sidebar .sidebar-content .list.active .sub-menu {
  max-height: 500px;
}
nav .sidebar .sidebar-content .list .sub-menu a {
  text-decoration: none;
  display: block;
  padding: 5px;
  margin: 5px 0px;
  font-size: 16px;
  color: #707070;
  font-weight: 400;
  cursor: pointer;
}
nav .sidebar .sidebar-content .list .sub-menu a:hover {
  background: linear-gradient(#dfe4e6, #eff2f4);
  color: #4b6a78;
  font-weight: 500;
}

script.js

const navBar = document.querySelector("nav"),
       menuBtns = document.querySelectorAll(".menu-icon"),
       overlay = document.querySelector(".overlay");

     menuBtns.forEach((menuBtn) => {
       menuBtn.addEventListener("click", () => {
         navBar.classList.toggle("open");
       });
     });

     overlay.addEventListener("click", () => {
       navBar.classList.remove("open");
     });

document.querySelectorAll("nav .sidebar .sidebar-content .list a").forEach(function(list){
  list.addEventListener("click",function(e){
    if(e.target.parentNode.children.length > 1){
      e.target.parentNode.classList.toggle("active");
    }
  });
});

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