fix(client): adjust CTA button width depending on viewport (#38432)

client/src/components/Intro/index.js

@@ -107,7 +107,7 @@ function Intro({
               <h2 className='medium-heading'>Spotify</h2>
             </div>
           </Col>
-          <Col sm={10} smOffset={1} xs={12}>
+          <Col md={6} mdOffset={3} sm={8} smOffset={2} xs={12}>
             <button
               className={'btn-cta-big signup-btn btn-cta center-block'}
               onClick={() => {

client/src/components/landing/index.js

@@ -16,7 +16,7 @@ const propTypes = {
 
 const BigCallToAction = () => (
   <Row>
-    <Col sm={10} smOffset={1} xs={12}>
+    <Col md={6} mdOffset={3} sm={10} smOffset={1} xs={12}>
       <Login block={true}>Sign in and get started (it's free)</Login>
     </Col>
   </Row>