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  <link rel="stylesheet" href="" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">

<div class="btn-group">  
<button type="button" class="btn btn-danger">Welcome</button>
  <button type="button" class="btn btn-danger dropdown-toggle dropdown-toggle-split" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    <span class="sr-only">Toggle Dropdown</span>
  <div class="dropdown-menu">
    <a class="dropdown-item" href="#">About me</a>
    <a class="dropdown-item" href="#">My accomplishments</a>
    <a class="dropdown-item" href="#">All my works</a>
    <div class="dropdown-divider"></div>
    <a class="dropdown-item" href="#">Learn more</a>
<div class="btn-group">
  <button type="button" class="btn btn-warning dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    HTML expert
  <div class="dropdown-menu">
    <h6 class="dropdown-header">HTML's hidden secrets</h6>
    <a class="dropdown-item active" href="#">What's HTML?</a>
    <a class="dropdown-item" href="#">What can you expect of HTML?</a>
    <a class="dropdown-item" href="#">How HTML benefits SEO?</a>
    <a class="dropdown-item" href="#">HTML Demo</a>
<div class="btn-group">
  <button type="button" class="btn btn-info dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    CSS Amateur
  <div class="dropdown-menu dropdown-menu-right">
    <a class="dropdown-item active" href="#">What's CSS?</a>
    <a class="dropdown-item" href="#">What can CSS do?</a>
    <a class="dropdown-item" href="#">Cool things about CSS</a>
    <a class="dropdown-item disabled" href="#">CSS Demo</a>
<div class="btn-group dropright">
  <button type="button" class="btn btn-outline-primary dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    Javascript Beginner
  <div class="dropdown-menu">
    <a class="dropdown-item" href="#">What is JS?</a>
    <a class="dropdown-item" href="#">How to fastest pick up JS?</a>
    <a class="dropdown-item" href="#">Future Career related to JS</a>
    <a class="dropdown-item" href="#">JS Demo</a>
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