client/web: style tweaks

Style changes made in live pairing session.

Updates #10261

Co-authored-by: Will Norris <will@tailscale.com>
Co-authored-by: Alessandro Mingione <alessandro@tailscale.com>
Signed-off-by: Sonia Appasamy <sonia@tailscale.com>

client/web/src/ui/card.tsx

@@ -0,0 +1,40 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+import cx from "classnames"
+import React from "react"
+
+type Props = {
+  children: React.ReactNode
+  className?: string
+  elevated?: boolean
+  empty?: boolean
+  noPadding?: boolean
+}
+
+/**
+ * Card is a box with a border, rounded corners, and some padding. Use it to
+ * group content into a single container and give it more importance. The
+ * elevation prop gives it a box shadow, while the empty prop a light gray
+ * background color.
+ *
+ *     <Card>{content}</Card>
+ *     <Card elevated>{content}</Card>
+ *     <Card empty><EmptyState description="You don't have any keys" /></Card>
+ *
+ */
+export default function Card(props: Props) {
+  const { children, className, elevated, empty, noPadding } = props
+  return (
+    <div
+      className={cx("rounded-md border", className, {
+        "shadow-soft": elevated,
+        "bg-gray-0": empty,
+        "bg-white": !empty,
+        "p-6": !noPadding,
+      })}
+    >
+      {children}
+    </div>
+  )
+}