discourse/plugins/chat/assets/stylesheets/common/chat-channel-selector-modal.scss

:root {
  --chat-channel-selector-input-height: 40px;
}

.chat-channel-selector-modal-modal.modal.in {
  animation: none;
}

#chat-channel-selector-modal-inner {
  width: 500px;
  height: 350px;

  .chat-channel-selector-input-container {
    position: relative;

    .search-icon {
      position: absolute;
      left: 10px;
      top: 50%;
      transform: translateY(-50%);
      color: var(--primary-high);
    }

    #chat-channel-selector-input {
      width: 100%;
      height: var(--chat-channel-selector-input-height);
      padding-left: 30px;
      margin: 0 0 1px;
    }
  }
  .channels {
    height: calc(100% - var(--chat-channel-selector-input-height));
    overflow: auto;

    .no-channels-notice {
      padding: 0.5em;
    }

    .chat-channel-selection-row {
      display: flex;
      align-items: center;
      height: 2.5em;
      padding-left: 0.5em;

      &.focused {
        background: var(--primary-low);
      }
      .username {
        margin-left: 0.5em;
      }
      .chat-channel-title {
        color: var(--primary-high);
      }

      .chat-channel-unread-indicator {
        border: none;
        margin-left: 0.5em;
        height: 12px;
        width: 12px;
      }
    }
  }
}