CSS opacity effecting the child divs - html

Question

I tried the opacity with the help of this. It does work well, except for one thing. The div where I want to use the opacity has other contents in it too. So, when I use opacity in that parent div, the child div also gets effected! What to do so as to effect only the parent div and not the child divs? Any help will be greatly appreciated. Thank you.
html:
<div id="profile_rightbar">
<div id="shortcuts">
<div class="icon pink">
<a href="#">
<p>Pictures</p>
<p>210</p>
</a>
</div>
<div class="icon green">
<a href="#">
<p>Videos</p>
<p>210</p>
</a>
</div>
<div class="icon blue">
<a href="#">
<p>Forums</p>
<p>210</p>
</a>
</div>
<div class="icon orange">
<a href="#">
<p>Pages</p>
<p>210</p>
</a>
</div>
<div class="icon pink">
<a href="#">
<p>Followers</p>
<p>210</p>
</a>
</div>
<div class="icon green">
<a href="#">
<p>Following</p>
<p>210</p>
</a>
</div>
</div>
<div id="status">
<p>Always do your best. What you plant now, you will harvest later.</p>
</div>
<div id="write">
<textarea id="redactor" name="content">
<h2>Hello and Welcome</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
</textarea>
</div>
<div id="activity">
<div class="picture">
<a href="#">
<p>The world is so perfect. How can one not love this beautiful world.</p>
<img src="image/world.jpg">
</a>
</div>
<div class="picture">
<a href="#">
<p>The world is so perfect. How can one not love this beautiful world.</p>
<img src="image/world.jpg">
</a>
</div>
<div class="forum">
<a href="#">
</a>
</div>
<div class="video">
<a href="#">
</a>
</div>
<div class="page">
<a href="#">
</a>
</div>
<div class="following">
<a href="#">
</a>
</div>
</div>
</div>
<div class="clear_right"></div>
css:
html, body {
width: 100%;
height: 100%;
}
#main_wrapper {
width:100%;
height: 100%;
background:url(../image/pantera.jpg) no-repeat center center fixed;
-webkit-background-size: cover;
-moz-background-size: cover;
-ms-background-size: cover;
-o-background-size: cover;
background-size: cover;
}
#profile_page {
width: 800px;
margin: 0 auto;
overflow: hidden;
border: 1px solid red;
}
#username h1 {
text-align: center;
color: white;
}
#profile_leftbar {
width: 210px;
float: left;
}
#profile_picture {
background-color: white;
border-radius: 10px;
border: 1px solid #dbdbdb;
}
#profile_picture img {
display: block;
margin: 0 auto;
border: none;
max-width:190px;
padding: 8px;
}
#about {
background: #f4f4f4;
border-radius: 5px;
margin-top: 8px;
border: 1px solid #dbdbdb;
}
#about p {
text-align: center;
color: #000000;
padding-top: 3px;
padding-bottom: 3px;
}
#about hr {
height:1px;
border:0px solid ;
border-top:1px solid #ccc;
}
#follow_message {
width: 210px;
margin: 5px auto;
}
#follow_message li {
list-style-type: none;
float: left;
margin-left: 3px;
}
#follow_message a {
display: block;
width: 101px;
text-align: center;
height: 30px;
color: white;
text-decoration: none;
line-height: 30px;
margin: 2px 0;
background: maroon;
}
#profile_rightbar {
float: right;
width: 590px;
}
#shortcuts {
overflow: hidden;
width: 588px;
margin: 0 auto;
}
#shortcuts div {
float: left;
margin: 4px;
}
.icon a {
text-decoration: none;
text-align: center;
display: block;
color: white;
border-radius: 5px;
width: 88px;
padding: 1px;
}
.icon a:hover {
text-decoration: underline;
}
.pink a {
background-color:#d63175;
}
.green a {
background-color:#51b73c;
}
.blue a {
background-color:#2f8ae0;
}
.orange a {
background-color:#f7a809;
}
#status {
background-color:white;
box-shadow:5px 5px 20px 1px black;
max-width:490px;
word-wrap:break-word;
padding:6px;
margin: 15px auto;
text-align:center;
font-size:30px;
line-height: 32px;
}
#write {
width: 575px;
margin: 0 auto;
}
#write textarea {
font-size:20px;
max-width:575px;
width: 575px;
}
#activity {
margin: 10px;
width: 575px;
}
#activity {
border: solid red;
opacity: 0.2;
filter: alpha(opacity=20); /* IE8 and lower */
zoom: 1;
#activity div {
background: white;
margin: 0 auto;
}
#activity .picture a img {
display: block;
max-width: 540px;
margin: 0 auto;
}
.picture a {
color: black;
text-decoration: none;
}
.picture a p {
margin-top:15px;
margin-left:15px;
}

Answer 1

dont use opacity it affects all child elements
Use
background-color : rgba(255,255,255,0.2);
which blurs only the parent element.