Demo here
1. Log in to your blogger account and Go to Design >>page Element
2.Click Add gadget and Select 'HTML/JavaScript'
3. Now paste paste below code
<style>
#nav1 {
margin: 0;
padding: 6px 7px 0;
height:37px;
background: #7d7d7d url(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtC-UKVVMVUur2rYQ4U3yKP3ZcbK-zfF29H2-g1EaELupD58fVX2wb0oDEWM8GAurLgHBykldHJ0uQ3Cqsr2JarjZPziyifzCdeuueNzhGHP7Fx9fCQTmmU-NpOcVnrwgAIkf7KLYJ477p/s320/image1.png) repeat-x 0 -110px;
line-height: 100%;
border-radius: 3em;
-webkit-border-radius: 3em;
-moz-border-radius: 3em;
-webkit-box-shadow: 0 1px 3px rgba(0,0,0, .4);
-moz-box-shadow: 0 1px 3px rgba(0,0,0, .4);
}
#nav1 li {
margin: 0 5px;
padding: 0 0 8px;
float: left;
position: relative;
list-style: none;
}
/* main level link */
#nav1 a {
font-weight: bold;
color: #000000;
text-decoration: none;
display: block;
padding: 8px 20px;
margin: 0;
-webkit-border-radius: 1.6em;
-moz-border-radius: 1.6em;
text-shadow: 0 1px 1px rgba(0,0,0, .3);
}
#nav1 a:hover {
background: #000;
color: #fff;
}
/* main level link hover */
#nav1 .current a, #nav1 li:hover > a {
background: #666 url(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgek4ME8dGxH8DxCor2t0bWxBX_bx6Rxc51XEK9IulXQXEGfVctGVG_TPP5EscOr-U8DwOywJIYkMrD1MrZ-VbeRReGA7xyka9bE_UXjVGTZB89DsDQ3rbEJGnfcFwhq5YBtZ25nhFF_2nz/s320/image1.png) repeat-x 0 -40px;
color: #444;
border-top: solid 1px #f8f8f8;
-webkit-box-shadow: 0 1px 1px rgba(0,0,0, .2);
-moz-box-shadow: 0 1px 1px rgba(0,0,0, .2);
box-shadow: 0 1px 1px rgba(0,0,0, .2);
text-shadow: 0 1px 0 rgba(255,255,255, 1);
}
/* sub levels link hover */
#nav1 ul li:hover a, #nav li:hover li a {
background: none;
border: none;
color: #666;
-webkit-box-shadow: none;
-moz-box-shadow: none;
}
#nav1 ul a:hover {
background: #0078ff url(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgek4ME8dGxH8DxCor2t0bWxBX_bx6Rxc51XEK9IulXQXEGfVctGVG_TPP5EscOr-U8DwOywJIYkMrD1MrZ-VbeRReGA7xyka9bE_UXjVGTZB89DsDQ3rbEJGnfcFwhq5YBtZ25nhFF_2nz/s320/image1.png) repeat-x 0 -100px !important;
color: #fff !important;
-webkit-border-radius: 0;
-moz-border-radius: 0;
text-shadow: 0 1px 1px rgba(0,0,0, .1);
}
/* dropdown */
#nav1 li:hover > ul {
display: block;
}
/* level 2 list */
#nav1 ul {
display: none;
margin: 0;
padding: 0;
width: 185px;
position: absolute;
top: 35px;
left: 0;
background: #ddd url(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtC-UKVVMVUur2rYQ4U3yKP3ZcbK-zfF29H2-g1EaELupD58fVX2wb0oDEWM8GAurLgHBykldHJ0uQ3Cqsr2JarjZPziyifzCdeuueNzhGHP7Fx9fCQTmmU-NpOcVnrwgAIkf7KLYJ477p/s320/image1.png) repeat-x 0 0;
border: solid 1px #b4b4b4;
-webkit-border-radius: 10px;
-moz-border-radius: 10px;
border-radius: 10px;
-webkit-box-shadow: 0 1px 3px rgba(0,0,0, .3);
-moz-box-shadow: 0 1px 3px rgba(0,0,0, .3);
box-shadow: 0 1px 3px rgba(0,0,0, .3);
}
#nav1 ul li {
float: none;
margin: 0;
padding: 0;
}
#nav1 ul a {
font-weight: normal;
text-shadow: 0 1px 0 #fff;
font-weight: bold;
color: #000000;
}
/* level 3+ list */
#nav1 ul ul {
left: 181px;
top: -3px;
}
/* rounded corners of first and last link */
#nav1 ul li:first-child > a {
-webkit-border-top-left-radius: 9px;
-moz-border-radius-topleft: 9px;
-webkit-border-top-right-radius: 9px;
-moz-border-radius-topright: 9px;
}
#nav1 ul li:last-child > a {
-webkit-border-bottom-left-radius: 9px;
-moz-border-radius-bottomleft: 9px;
-webkit-border-bottom-right-radius: 9px;
-moz-border-radius-bottomright: 9px;
}
/* clearfix */
#nav1:after {
content: ".";
display: block;
clear: both;
visibility: hidden;
line-height: 0;
height: 0;
}
#nav1 {
display: inline-block;
}
</style>
<ul id="nav1">
<li class="current"><a href="/">Home</a></li>
<li><a href="3">level1</a>
<ul>
<li><a href="#">Link 1</a></li>
<li><a href="#">Link 2</a></li>
<li><a href="#">Link 3</a></li>
<li><a href="#">Link 4</a></li>
</ul>
</li>
<li><a href="#">Multi-Levels</a>
<ul>
<li><a href="#">Link 1</a></li>
<li><a href="#">Link 2</a></li>
<li><a href="#">Link 3</a></li>
<li><a href="#">Link 4</a></li>
</ul>
</li>
<li><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
</ul>
* Replace with # your links.
* Replace with link your names.
4. Now save 'HTML/JavaScript'. you are done.