Ultra simple, no bullshit pitch-black theme. Compatible with all client mods.

discord-pitch-black.scss

.theme-dark {
  &:root {
    --background-primary: #000;
    --background-secondary: #000;
    --background-tertiary: #000;
    --deprecated-panel-background: #000;
    --channeltextarea-background: #101010;
  }

  .topSectionNormal-2-vo2m, .body-3ND3kc, .container-3ayLPN, .modal-yWgWj-, .autocomplete-1vrmpx, .emojiPicker-3m1S-j {
    background-color: #101010;
  }

  // Popout
  .header-ykumBX {
    background-color: #090909;

    .title-2-NHs5 {
      color: #fff;
    }
  }

  .messagesPopoutWrap-1MQ1bW {
    background-color: #181818;
    border: 1px #202020 solid;

    .messageGroupWrapper-o-Zw7G {
      border: none;
      background-color: transparent;

      &:hover .actionButtons-1sUUug {
        box-shadow: none;
        background-color: transparent;
      }
    }

    .messagesPopout-24nkyi {
      background-color: transparent;
    }
  }

  .headerNormal-T_seeN {
    background-color: #080808;
  }

  .bodyInner-245q0L {
    background-color: #151515;
  }

  .footer-1fjuF6 {
    border-color: #050505;
    background-color: #151515;
    color: hsla(0, 0%, 100%, .8);

    .quickMessage-1yeL4E {
      background-color: #202020;
      border-color: #202020;
    }
  }

  // Search
  .focused-2bY0OD {
    background-color: #151515;
  }

  .option-96V44q {
    &:after {
      display: none;
    }

    &.selected-rZcOL- {
      background-color: #202020;
    }
  }

  .searchResultsWrap-2DKFzt {
    background-color: transparent;

    .searchHeader-1l-wpR, .channelSeparator-1X1FuH .channelName-1QajIf {
      background-color: inherit;
    }

    .searchResult-3pzFAB:before, .searchResult-3pzFAB:after {
      display: none;
    }

    .searchResultMessage-2VxO12.hit-NLlWXA {
      background-color: #101010;
      border-color: #000;
      box-shadow: none;
    }
  }

  // Modals
  .topSectionNormal-2-vo2m .tabBarContainer-1s1u-z {
    border-top: none;
    border-bottom: 1px #050505 solid;
  }

  .footer-3rDWdC {
    background-color: #151515;
    box-shadow: none;
  }

  // Message
  .selectorSelected-1_M1WV {
    background-color: #202020;
  }

  .emojiPicker-3m1S-j {
    infoBar-U6oBFk, .categories-1feg4n {
      background-color: #171717;
    }
  }

  .embedWrapper-3AbfJJ {
    background-color: #101010;
    border-left-color: #151515;
  }

  // Server Boost
  .perksModal-fSYqOq {
    background-color: #000;

    .ctaBar-2UsjF2, .perk-2WeBWW {
      background-color: #101010;
    }
  }

  .tierHeaderLocked-1a2opw {
    background-color: #151515;
  }

  .tierBody-x9kBBp {
    background-color: #101010;
  }

  // Server Discovery
  .pageWrapper-1PgVDX {
    background-color: #000;
  }

  .searchBox-3Y2Vi7 {
    background-color: #101010;
  }

  .card-3DjzTQ {
    background: #050505;

    &:hover {
      background-color: #101010;
      box-shadow: none;
    }
  }

  // Stuff
  .friendsTable-133bsv {
    background-color: #000;
  }

  // Scrollbar
  .base-3dtUhz .scroller-2FKFPG::-webkit-scrollbar-thumb {
    background-color: #252525 !important;
    border-color: #000 !important;
    border-radius: 0;
  }

  .base-3dtUhz .scroller-2FKFPG::-webkit-scrollbar-track-piece {
    background-color: #000 !important;
    border-color: #000 !important;
  }
}