Lightning Component (Sample.cmp):

<!--Sample.cmp--> 
<aura:component implements="flexipage:availableForAllPageTypes">
    <div class="marquee">
        <p>
            <a title="Welcome to Biswajeet Samal's Blog" href="http://biswajeetsamal.com/blog" target="_blank">Welcome to Biswajeet Samal's Blog</a>
        </p>
    </div>
</aura:component>

Lightning Component Style (Sample.css):

.marquee.THIS {
    width: 100%;
    line-height: 50px;
    color: white;
    white-space: nowrap;
    overflow: hidden;
    box-sizing: border-box;
    background-color: red;
}

.marquee.THIS p {
    display: inline-block;
    padding-left: 100%;
    animation: marquee 20s linear infinite;
    font-size:30px;
}

@keyframes marquee {
    0%   { transform: translate(0, 0); }
    100% { transform: translate(-100%, 0); }
}

Output: