If you want some styles to apply specifically to slot content, you can do that with the :slotted pseudo-selector:
<style scoped>/* Add margin to <p> tags within the slot */:slotted(p) {margin: 15px 5px;}</style>
You can also use :global to have styles apply to global scope, even within the <style scoped> block:
<style scoped>:global(body) {margin: 0;padding: 0;font-family: sans-serif;}</style>
Of course, if you have lots of global styles you want to add, it's probably easier to just add a second <style> block:
<style scoped>/* Add margin to <p> tags within the slot */:slotted(p) {margin: 15px 5px;}</style><style>body {margin: 0;padding: 0;font-family: sans-serif;}</style>
Check out the docs for more info.