css – 根据div大小调整字体大小

html：

<div id="launchmain" >
<div id="box1"></div>
<div id="box2"></div>
<div id="box3"></div>
<div id="box4"></div>
    <div id ="maininvite">
        <h2> header</h2>
        <p>not a lot of text here but still overflowing</p>
    </div>
<div id="box6"></div>
<div id="box7"></div>
<div id="box8"></div>
<div id="box9"></div>
</div>

用css：

html,body {
 height: 100%;
 width: 100%;    
}
#launchmain {
 width: 55%;
 display: inline-block;
 position: relative;
    top:10%;
    left:25%;
}
#launchmain:after {
    padding-top: 79.26%; 
    display: block;
    content: '';
    margin-top: 10px;
}
#box1
{
    border: 1px solid #000000;

    position: absolute;
    width:25.37%; 
    height:21.88%            
}
#box2
{
    border: 1px solid #000000;
    width: 48.48%;
    height:21.88%;
    position: absolute;
    left:25.64%
}
#box3
{
    border: 1px solid #000000;
    width:25.37%; 
    height:21.88%;
    position: absolute;
    left:74.39%;
}
#box4
{
    border: 1px solid #000000;
    width:33.235%; 
    height:53.84%;
    position: absolute;
    top:22.07%;
}
#maininvite
{
    border: 1px solid #000000;
    width:33.53%; 
    height:53.84%;
    position: absolute;
    top:22.07%;
    left: 33.235%;
}
#box6
{
    border: 1px solid #000000;
    width:33.235%; 
    height:53.84%;
    position: absolute;
    top:22.07%;
    left: 66.765%;
}
#box7
{
    border: 1px solid #000000;
   width:25.37%; 
    height:21.88% ;
    position: absolute;
    top:76.2%;

}
#box8
{
    border: 1px solid #000000;
  width: 48.48%;
    height:21.88%;
    position: absolute;
   left:25.64%;
    top:76.2%;
}
#box9
{
    border: 1px solid #000000;
    width:25.37%; 
    height:21.88% ;
    position: absolute;
    top:76.2%;
    left:74.39%;
}
#maininvite h2{

    font-size: 180%;
}

p{
    position: relative;
    font-size: 80%;
}
​

它由9个盒子组成,中间有文字.
我已经做了这样的框,所以他们将调整大小,屏幕调整大小,所以它将一直保持在同一个地方.

然而,文本不会调整大小 – 即使我使用百分比.

>如何调整文本大小,使其始终与整个页面的比例相同？
这是处理多种分辨率的正确解决方案吗？或者我应该在css中有很多@media检查,并且每种媒体类型都有很多布局？