You can attain such a setup using new CSS3 facilities, namely border-radius and gradient form of background image. You can find information about those all around the internet, for example background gradient and border radius.
Below is example, it will not work in all browsers, and is not exactly what you want, but it should be enough to give you the basic idea:
The html structure could look like this:
<div id="big_div">
Search for a hotel
<div id="small_white_div">
Some other content
</div>
</div>
And the corresponding css would be:
#big_div {height:450px;width:250px;border-radius: 5px;background-color:red;
background-image: linear-gradient(bottom, rgb(33,51,140) 5%, rgb(125,187,209) 51%,
rgb(33,51,140) 100%);
background-image: -o-linear-gradient(bottom, rgb(33,51,140) 5%, rgb(125,187,209) 51%,
rgb(33,51,140) 100%);
background-image: -moz-linear-gradient(bottom, rgb(33,51,140) 5%, rgb(125,187,209)
51%, rgb(33,51,140) 100%);
background-image: -webkit-linear-gradient(bottom, rgb(33,51,140) 5%, rgb(125,187,209)
51%, rgb(33,51,140) 100%);
background-image: -ms-linear-gradient(bottom, rgb(33,51,140) 5%, rgb(125,187,209) 51%,
rgb(33,51,140) 100%);
background-image: -webkit-gradient(
linear,
left bottom,
left top,
color-stop(0.05, rgb(33,51,140)),
color-stop(0.51, rgb(125,187,209)),
color-stop(1, rgb(33,51,140))
);}
#small_white_div {height:400px;width:220px;margin:auto;border-radius:5px;
background-color:white;margin-top:20px;}
Good luck.