<style type="text/css">
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    #div-before, #div-after {
        background-color:#aee;
        color:#000;
        width:400px;
    }
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    #div-1 {
        width:400px;
        background-color:#000;
        color:#fff;
        position: absolute; //        
    }  
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    #div-1a {        
        background-color:#d33;
        color:#fff;
        position: absolute;  //绝对定位  
        right: 0px; //     
        top: 0px; //
    }  
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    #div-1-padding {
        padding:20px;
    }
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</style>
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<div>
 
    <div id="div-before">  
        <p>id = div-before</p> 
    </div>
 
    <div id="div-1">
        <div id="div-1-padding">
            <p>id = div-1</p>
            <div id="div-1a">
                <p>id = div-1a</p>
                <p>Lorem ipsum dolor sit amet.</p>
            </div>
            <div id="div-1b">
                <p>id = div-1b</p>
                <p>Lorem ipsum dolor sit amet .</p>
            </div>
        </div>
    </div>
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     <div id="div-after">  
        <p>id = div-after</p> 
    </div>
 
</div>