divをそのコンテンツ以下にする方法を教えてください。

div {
  display: inline-block;
}

<div>
  <table>
    <tr>
      <td>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi ultrices feugiat massa sed laoreet. Maecenas et magna egestas, facilisis purus quis, vestibulum nibh.</td>
      <td>Nunc auctor aliquam est ac viverra. Sed enim nisi, feugiat sed accumsan eu, convallis eget felis. Pellentesque consequat eu leo nec pharetra. Aenean interdum enim dapibus diam.</td>
      <td>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi ultrices feugiat massa sed laoreet. Maecenas et magna egestas, facilisis purus quis, vestibulum nibh.</td>
    </tr>
  </table>
</div>

.floating-box {
    display:-moz-inline-stack;
    display: inline-block;

    width: fit-content; 
    height: fit-content;

    width: 150px;
    height: 75px;
    margin: 10px;
    border: 3px solid #73AD21;  
}

<h2>The Way is using inline-block</h2>

Supporting elements are also added in CSS.

<div>
   <div class="floating-box">Floating box</div>
   <div class="floating-box">Floating box</div>
   <div class="floating-box">Floating box</div>
   <div class="floating-box">Floating box</div>
   <div class="floating-box">Floating box</div>
   <div class="floating-box">Floating box</div>
   <div class="floating-box">Floating box</div>
   <div class="floating-box">Floating box</div>
</div>

body {
    font-family: sans-serif;
}
.top {
    display: -webkit-inline-flex;
    display: inline-flex;
}
.top, .bottom {
    background-color: #3F3;
    border: 2px solid #FA6;
}
/* bottomwrapper will take the rest of the width */
.bottomwrapper {
    display: -webkit-flex;
    display: flex;
}
table {
    border-collapse: collapse;
}
table, th, td {
    width: 280px;
    border: 1px solid #666;
}
th {
    background-color: #282;
    color: #FFF;
}
td {
    color: #444;
}
th, td {
    padding: 0 4px 0 4px;
}

Is this
<div class="top">
	<table>
        <tr>
            <th>OS</th>
            <th>Version</th> 
        </tr>
        <tr>
            <td>OpenBSD</td>
            <td>5.7</td> 
        </tr>
        <tr>
            <td>Windows</td>
            <td>Please upgrade to 10!</td> 
        </tr>
    </table>
</div>
what you are looking for?
<br>
Or may be...
<div class="bottomwrapper">
    <div class="bottom">
    	<table>
            <tr>
                <th>OS</th>
                <th>Version</th> 
            </tr>
            <tr>
                <td>OpenBSD</td>
                <td>5.7</td> 
            </tr>
            <tr>
                <td>Windows</td>
                <td>Please upgrade to 10!</td> 
            </tr>
        </table>
    </div>
</div>
this is what you are looking for.

div {
  display: inline-block;
  display:-moz-inline-stack;
  zoom:1;
  *display:inline;
  border-style: solid;
  border-color: #0000ff;
}

<div>
  <table>
    <tr>
      <td>Column1</td>
      <td>Column2</td>
      <td>Column3</td>
    </tr>
  </table>
</div>

div {
  display: inline-block;
  padding: 2vw;
  background-color: green;
}

table {
  width: 70vw;
  background-color: white;
}

<div>
    <table border="colapsed">
      <tr>
        <td>Apple</td>
        <td>Banana</td>
        <td>Strawberry</td>
      </tr>
      <tr>
        <td>Apple</td>
        <td>Banana</td>
        <td>Strawberry</td>
      </tr>
      <tr>
        <td>Apple</td>
        <td>Banana</td>
        <td>Strawberry</td>
      </tr>

    </table>
</div>

$('button').click(function(){

  $('nav ul').each(function(){
    
    $parent = $(this).parent();
    
    $parent.width( $(this).width() );
    
  });
});

nav {
  display: inline-block;
  text-align: left; /* doesn't do anything, unlike some might guess */
}
ul {
  display: inline;
}

/* needed style */
ul {
  padding: 0;
}
body {
  width: 420px;
}

/* just style */
body {
  background: #ddd;
  margin: 1em auto;
}
button {
  display: block;
}
nav {
  background: #bbb;
  margin: 1rem auto;
  padding: 0.5rem;
}
li {
  display: inline-block;
  width: 40px;
  height: 20px;
  border: solid thin #777;
  margin: 4px;
  background: #999;
  text-align: center;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<button>fix</button>

<nav>
  <ul>
    <li>3</li>
    <li>.</li>
    <li>1</li>
    <li>4</li>
  </ul>
</nav>

<nav>
  <ul>
    <li>3</li>
    <li>.</li>
    <li>1</li>
    <li>4</li>
    <li>1</li>
    <li>5</li>
    <li>9</li>
    <li>2</li>
    <li>6</li>
    <li>5</li>
    <li>3</li>
    <li>5</li>
  </ul>
</nav>