So this would be an example for the Homeworld Theme. Building the theme with the website editor left me without a working custom font but all other elements in working order. In order to get the custom font to work I had to add the "@font-face {}" section to load source the font files first. Then you can reference the font name where you want it.
I see in this theme file it sources a "main.css" which means someone with good experience could build a completely custom layout beyond just the theme code.
Code:
/**
* @name Homeworld_ReaverVI
* @author ClearVision Team
* @version 6.9.0
* @description Highly customizable and beautiful theme for BetterDiscord.
* @source https://github.com/ClearVision/ClearVision-v6
* @website https://clearvision.github.io
* @invite dHaSxn3
* @BDEditor Clear Vision
*/
@import url('https://clearvision.github.io/ClearVision-v6/main.css');
@font-face {
font-family: "Microgramma D Bold Extended";
src: url("https://db.onlinewebfonts.com/t/49441315ab9ce55176682715f25ea4b2.eot");
src: url("https://db.onlinewebfonts.com/t/49441315ab9ce55176682715f25ea4b2.eot?#iefix")format("embedded-opentype"),
url("https://db.onlinewebfonts.com/t/49441315ab9ce55176682715f25ea4b2.woff2")format("woff2"),
url("https://db.onlinewebfonts.com/t/49441315ab9ce55176682715f25ea4b2.woff")format("woff"),
url("https://db.onlinewebfonts.com/t/49441315ab9ce55176682715f25ea4b2.ttf")format("truetype"),
url("https://db.onlinewebfonts.com/t/49441315ab9ce55176682715f25ea4b2.svg#Microgramma D Bold Extended")format("svg");
}
:root {
--main-color: #0006FF;
--hover-color: #FFEC00;
--success-color: #00FF8B;
--danger-color: #982929;
--url-color: var(--main-color);
--background-image: url('https://i.imgur.com/0o36wzB.jpeg');
--background-shading: 100%;
--background-position: center;
--background-size: cover;
--background-repeat: no-repeat;
--background-attachment: fixed;
--background-brightness: 100%;
--background-contrast: 100%;
--background-saturation: 100%;
--background-grayscale: 0%;
--background-invert: 0%;
--background-blur: 0px;
--background-overlay: rgb(0,51,255,0.13);
--user-popout-image: url('https://i.imgur.com/ec40T.jpeg');
--user-popout-position: center right;
--user-popout-size: contain;
--user-popout-repeat: no-repeat;
--user-popout-attachment: fixed;
--user-popout-brightness: 100%;
--user-popout-contrast: 300%;
--user-popout-saturation: 100%;
--user-popout-grayscale: 100%;
--user-popout-invert: 0%;
--user-popout-blur: 2px;
--user-modal-image: url('https://i.imgur.com/aRsITbN.jpeg');
--user-modal-position: center;
--user-modal-size: contain;
--user-modal-repeat: no-repeat;
--user-modal-attachment: fixed;
--user-modal-brightness: 172%;
--user-modal-contrast: 221%;
--user-modal-saturation: 100%;
--user-modal-grayscale: 0%;
--user-modal-invert: 0%;
--user-modal-blur: 0px;
--home-icon: url('https://i.imgur.com/bp87HA2.png');
--home-position: center;
--home-size: 34px;
--channel-unread: #C1D100CF;
--channel-color: rgb(0,142,255,1);
--muted-color: rgb(255,0,0,1);
--online-color: #8BC34A;
--idle-color: #faa61a;
--dnd-color: #982929;
--streaming-color: #593695;
--offline-color: #808080;
--main-font: Microgramma D;
--code-font: Courier;
--channels-width: 220px;
--members-width: 240px;
--backdrop-overlay: rgba(0,0,0,0.8);
--backdrop-image: var(--background-image);
--backdrop-position: var(--background-position);
--backdrop-size: var(--background-size);
--backdrop-repeat: var(--background-repeat);
--backdrop-attachment: var(--background-attachment);
--backdrop-brightness: var(--background-brightness);
--backdrop-contrast: var(--background-contrast);
--backdrop-saturation: var(--background-saturation);
--backdrop-invert: var(--background-invert);
--backdrop-grayscale: var(--background-grayscale);
--backdrop-sepia: var(--background-sepia);
--backdrop-blur: var(--background-blur);
--bd-blue: var(--main-color);
--bd-blue-hover: var(--hover-color);
--bd-blue-active: var(--hover-color);
}
/* Any custom CSS below here */