feat(button): focus state

src/components/button.js

@@ -1,12 +1,27 @@
 import React from "react";
 import styled from "@emotion/styled";
+import { css } from "@emotion/react";
 
 const Container = styled.button`
   background-color: transparent;
   margin: 0;
   padding: 4px 8px;
-  border: 1px solid var(--color-black);
-  border-radius: 4px;
+  border: 1px solid var(--color-dark);
+  font-size: var(--font-size-md);
+  ${props =>
+    props.float &&
+    css`
+      float: ${props.float};
+    `}
+
+  &:focus {
+    outline: 0;
+    box-shadow: 0 0 0 2px var(--color-dark);
+  }
+
+  &:focus:not(:focus-visible) {
+    box-shadow: none;
+  }
 `;
 
 export default function Button({ children, ...other }) {