discourse/app/assets/stylesheets/desktop/compose.scss

#reply-control {
  .reply-area {
    margin: 0 auto;
    padding: 5px 15px;
    box-sizing: border-box;
    height: calc(100% - 11px);
    width: 100%;
    .submit-panel {
      flex-wrap: wrap;
      align-items: center;
    }
  }

  #private-message-users {
    width: 404px;
  }

  .item + #private-message-users {
    width: unset;
    min-width: 150px;
    flex: 1 1 auto;
  }

  .select-kit.is-expanded {
    z-index: z("composer", "dropdown") + 1;
  }
}

.edit-title {
  --overflow-buffer: 1em;
  // this gives text little space to overflow without being cropped (e.g., Õ in headings)

  .d-editor-preview-wrapper {
    margin-top: calc(-41px - var(--overflow-buffer));
    padding-top: var(--overflow-buffer);
  }
  &:not(.private-message) {
    .d-editor-preview-wrapper {
      @media screen and (max-width: 955px) {
        margin-top: calc(-75px - var(--overflow-buffer));
      }
    }
  }

  .with-tags {
    .d-editor-preview-wrapper {
      margin-top: calc(-75px - var(--overflow-buffer));
    }
  }
}

.closed {
  .grippie {
    display: none;
  }
}

.open {
  .grippie {
    cursor: row-resize;
    padding: 4px 0;
    background: var(--tertiary);
    &:before {
      content: "";
      display: block;
      width: 27px;
      margin: auto;
      border-top: 3px double var(--secondary);
    }
  }
}

.discourse-touch {
  .open {
    .grippie {
      padding: 7px 0;
    }
  }
}

.composer-popup-container {
  max-width: 1500px;
  margin-left: auto;
  margin-right: auto;
}

.composer-popup {
  position: absolute;
  width: calc(50% - 45px);
  max-width: 724px;
  top: 20px;
  bottom: 10px;
  left: 51%;
  overflow-y: auto;
  z-index: z("composer", "popover");
  padding: 10px 10px 35px 10px;
  box-shadow: shadow("card");
  background: var(--highlight-medium);
  .hide-preview & {
    z-index: z("composer", "dropdown") + 1;
  }

  &.urgent {
    background: var(--danger-low);
  }

  &.education-message {
    background-color: var(--tertiary-low);
  }

  h3 {
    margin-bottom: 10px;
  }

  p {
    margin-bottom: 10px;
  }

  a.close {
    display: flex;
    align-items: center;
    position: absolute;
    right: 10px;
    top: 10px;
    color: var(--primary);
    opacity: 0.5;
    font-size: $font-up-1;
    &:before {
      content: "esc";
      font-size: $font-down-1;
      margin-right: 0.5em;
    }
  }

  a.close:hover {
    opacity: 1;
  }

  ul {
    margin: 0;
    padding: 0 0 0 1.5em;
    &.list,
    &.topics {
      list-style: none;
      padding: 0;
    }

    li {
      font-weight: normal;
      margin-top: 8px;
    }
  }
}

.composer-controls {
  .d-chevron-down {
    vertical-align: text-top;
  }
}

.custom-body {
  background-color: var(--tertiary-low);
  p {
    max-width: 98%;
  }
}

.similar-topics {
  background-color: var(--tertiary-low);

  a[href] {
    color: var(--primary);
  }

  .posts-count {
    background-color: var(--tertiary);
  }

  .search-link {
    .topic-title {
      flex: 0 1 auto;
      margin-right: 0.5em;
    }
    .topic-statuses:empty {
      display: none;
    }
    span.badge-wrapper {
      margin-left: 0;
    }
    .blurb {
      color: var(--primary-high);
    }
    .topic-title,
    .blurb {
      .d-icon {
        color: var(--primary-high);
      }
    }
    span.topic {
      display: flex;
      flex-direction: column;

      .first-line {
        flex: 1;
      }

      .second-line {
        display: flex;
        flex-wrap: wrap;
        align-items: center;

        .discourse-tags {
          font-size: $font-down-1;
        }
      }
    }
  }
}

.composer-popup:nth-of-type(2) {
  margin-left: 10px;
  width: calc(50% - 65px);
}

a.toggle-preview {
  color: var(--primary-high);
  &:hover {
    color: var(--tertiary);
  }
}

#draft-status,
#file-uploading {
  flex-grow: 1;
  text-align: right;
}

// fullscreen composer styles
.fullscreen-composer {
  overflow: hidden;

  .profiler-results {
    display: none;
  }
  #reply-control {
    &.fullscreen {
      // important needed because of inline styles when height is changed manually with grippie
      height: 100vh !important;
      max-height: 100%; // prevents devices from miscalculating using vh
      @supports (--custom: property) {
        height: calc(var(--composer-vh, 1vh) * 100) !important;
      }
      z-index: z("header") + 1;
      .d-editor-preview-wrapper {
        margin-top: 1%;
      }
      .reply-to {
        border-bottom: 1px solid var(--primary-low);
        padding-bottom: 3px;
        margin: 0;
        .composer-controls {
          margin-right: 0;
        }
      }
      .d-editor-textarea-wrapper {
        border: none;
      }
      &.show-preview .d-editor-textarea-wrapper {
        border-right: 1px solid var(--primary-low);
      }
      #draft-status,
      #file-uploading {
        margin-left: 0;
        text-align: initial;
      }
      .composer-popup {
        top: 30px;
      }
      &:before {
        content: "";
        background: var(--secondary);
        width: 100%;
        height: 100%;
        position: fixed;
        z-index: -1;
        left: 0;
      }
    }
  }
}