Header+Footer: fix copy and improve elevator btn

src/components/Footer/Footer.css

@@ -56,21 +56,20 @@ footer .links {
 
 @media screen and (max-width: 719px) {
   #back-to-top-button {
-    position: sticky;
+    position: fixed;
-    top: calc(100% - 64px);
+    bottom: 20px;
-    float: right;
+    right: 20px;
     display: flex;
     align-items: center;
     justify-content: center;
-    width: 48px;
+    width: 56px;
-    height: 48px;
+    height: 56px;
     padding: 0;
-    margin: 16px;
   }
 
   #back-to-top-button img {
-    width: 24px;
+    width: 28px;
-    height: 24px;
+    height: 28px;
   }
 
   footer .links {

src/components/Footer/Footer.tsx

@@ -26,13 +26,6 @@ const Footer: React.FC<FooterProps> = () => {
           <img src={uArrowUpLeft} alt="" />
         </button>
         <div className="outro">
-          {/* <img id="command" src={commandKeySpec} alt="" />
-          <img
-            id="command"
-            className="inspectable xray"
-            src={commandKey}
-            alt=""
-          /> */}
           <Links />
           <p>
             We designed the icon library we always wanted to use. Easy to pick
@@ -41,7 +34,7 @@ const Footer: React.FC<FooterProps> = () => {
             a little quirky, too.
           </p>
           <p>
-            We're thankful for the open-source tools we've benefited from and
+            We're thankful for the tools we've benefited from and
             this is our small contribution towards a collaborative digital
             community.
           </p>

src/components/Header/Header.tsx

@@ -56,14 +56,14 @@ const Header: React.FC<HeaderProps> = () => {
         </div>
         <div className="intro">
           <h2>
-            Phosphor is a flexible icon family for interfaces, presentations — 
+            Phosphor is a flexible icon family for interfaces, diagrams, presentations — 
             <wbr />
             whatever, really.
           </h2>
           <div className="button-container">
             <button className="main-button" onClick={handleGetStarted}>
               <ArrowCircleUpRight size={24} weight="fill" />
-              See the docs
+              Get started
             </button>
             <button className="main-button" onClick={handleScrollToIcons}>
               <ArrowCircleDown size={24} weight="fill" />