discourse/plugins/chat/assets/stylesheets/common/chat-message.scss

.chat-message-deleted,
.chat-message-hidden {
  margin-left: calc(var(--message-left-width) + 0.75em);
  padding: 0;

  .chat-message-expand {
    color: var(--primary-low-mid);
    padding: 0.25em;

    &:hover {
      background: inherit;
      color: inherit;
    }
  }
}

@mixin chat-reaction {
  align-items: center;
  display: inline-flex;
  padding: 0.3em 0.6em;
  margin: 1px 0.25em 1px 0;
  font-size: var(--font-down-2);
  border-radius: 4px;
  border: 1px solid var(--primary-low);
  background: transparent;
  cursor: pointer;
  user-select: none;
  transition: background 0.2s, border-color 0.2s;

  &.reacted {
    border-color: var(--tertiary-medium);
    background: var(--tertiary-very-low);
    color: var(--tertiary-hover);

    &:hover {
      background: var(--tertiary-low);
    }
  }

  &:not(.reacted) {
    &:hover {
      background: var(--primary-low);
      border-color: var(--primary-low-mid);
    }

    &:focus {
      background: none;
    }
  }

  .emoji {
    height: 15px;
    margin-right: 4px;
    width: auto;
  }
}

.chat-message {
  align-items: flex-start;
  padding: 0.25em 0.5em 0.25em 0.75em;
  background-color: var(--secondary);
  display: flex;
  min-width: 0;

  .chat-message-reaction {
    @include chat-reaction;
  }

  &.chat-action {
    background-color: var(--highlight-bg);
  }

  &.errored {
    color: var(--primary-medium);
  }

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

  .not-mobile-device &.deleted:hover {
    background-color: var(--danger-hover);
  }

  &.is-reply {
    display: grid;
    grid-template-columns: var(--message-left-width) 1fr;
    grid-template-rows: 30px auto;
    grid-template-areas:
      "replyto replyto"
      "avatar message";

    .chat-user-avatar {
      grid-area: avatar;
    }

    .chat-message-content {
      grid-area: message;
    }
  }

  .chat-message-content {
    display: flex;
    flex-direction: column;
    flex-grow: 1;
    word-break: break-word;
    overflow-wrap: break-word;
    min-width: 0;
  }

  .chat-message-text {
    min-width: 0;
    width: 100%;

    code {
      box-sizing: border-box;
      font-size: var(--font-down-1);
      width: 100%;
    }

    .mention.highlighted {
      background: var(--tertiary-low);
      color: var(--primary);
      display: inline-block;
      font-size: 0.93em;
      font-weight: normal;
      padding: 0 0.3em 0.07em;
      border-radius: 0.6em;
      text-decoration: none;
    }

    img.ytp-thumbnail-image,
    img.youtube-thumbnail {
      height: 100%;
      max-height: unset;

      &:hover {
        border-radius: 0;
      }
    }

    // Automatic aspect-ratio mapping https://developer.mozilla.org/en-US/docs/Web/Media/images/aspect_ratio_mapping
    p img:not(.emoji) {
      max-width: 100%;
      height: auto;
    }

    ul,
    ol {
      padding-left: 1.25em;
    }
  }

  .chat-message-edited {
    display: inline-block;
    color: var(--primary-medium);
    font-size: var(--font-down-2);
  }

  .chat-message-reaction-list,
  .chat-transcript-reactions {
    @include unselectable;
    margin-top: 0.25em;
    display: flex;
    flex-wrap: wrap;

    .reaction-users-list {
      position: absolute;
      top: -2px;
      transform: translateY(-100%);
      border: 1px solid var(--primary-low);
      border-radius: 6px;
      padding: 0.5em;
      background: var(--primary-very-low);
      max-width: 300px;
      z-index: 3;
    }

    .chat-message-react-btn {
      vertical-align: top;
      padding: 0em 0.25em;
      background: none;
      border: none;

      .d-icon {
        color: var(--primary-high);
      }

      &:hover {
        .d-icon {
          color: var(--primary);
        }
      }
    }
  }

  .chat-send-error {
    color: var(--danger-medium);
  }

  .chat-message-mention-warning {
    position: relative;
    margin-top: 0.25em;
    font-size: var(--font-down-1);

    .dismiss-mention-warning {
      position: absolute;
      top: 15px;
      right: 5px;
      cursor: pointer;
    }

    .warning-item {
      margin: 0.25em 0;
    }

    .invite-link {
      color: var(--tertiary);
      cursor: pointer;
    }
  }

  .chat-message-avatar .chat-user-avatar .chat-user-avatar-container .avatar,
  .chat-emoji-avatar .chat-emoji-avatar-container {
    width: 28px;
    height: 28px;
  }
}

.chat-message-container.highlighted .chat-message {
  background-color: var(--tertiary-low) !important;
}

.chat-messages-container {
  .not-mobile-device & .chat-message:hover,
  .chat-message.chat-message-selected {
    background: var(--primary-very-low);
  }

  .chat-message.chat-message-bookmarked {
    background: var(--highlight-bg);

    &:hover {
      background: var(--highlight-medium);
    }
  }

  .not-mobile-device & .chat-message-reaction-list .chat-message-react-btn {
    display: none;
  }

  .not-mobile-device & .chat-message:hover {
    .chat-message-reaction-list .chat-message-react-btn {
      display: inline-block;
    }
  }
}

.chat-message-flagged {
  display: inline-block;
  color: var(--danger);
  height: 100%;
  padding: 0 0.3em;
  cursor: pointer;

  .flag-count,
  .d-icon {
    color: var(--danger);
  }
}

.chat-action-text {
  font-style: italic;
}

.chat-message-container.is-hovered,
.chat-message.chat-message-selected {
  background: var(--primary-very-low);
}

.chat-message.chat-message-bookmarked {
  background: var(--highlight-bg);
}

.has-full-page-chat .chat-message .onebox:not(img),
.chat-drawer-container .chat-message .onebox {
  margin: 0.5em 0;
  border-width: 2px;

  header {
    margin-bottom: 0.5em;
  }

  h3 a,
  h4 a {
    font-size: 14px;
  }

  pre {
    display: flex;
    max-height: 150px;
  }

  p {
    overflow: hidden;
  }
}

.chat-drawer-container .chat-message .onebox {
  width: 85%;
  border: 2px solid var(--primary-low);

  header {
    margin-bottom: 0.5em;
  }

  .onebox-body {
    grid-template-rows: auto auto auto;
    overflow: auto;
  }

  h3 {
    @include line-clamp(2);
    font-weight: 500;
    font-size: var(--font-down-1);
  }

  p {
    display: none;
  }
}

.chat-message-reaction {
  > * {
    pointer-events: none;
  }
}

.retry-staged-message-btn {
  padding: 0.5em 0;
  background: none;

  &:hover,
  &:focus,
  &:active {
    background: none !important;
  }

  &:focus .retry-staged-message-btn__action {
    text-decoration: underline;
  }

  .d-icon,
  &__title,
  &:hover .d-icon {
    color: var(--danger) !important;
    font-size: var(--font-down-1);
  }

  .d-icon {
    margin-right: 0.25em !important;
  }

  &__action {
    color: var(--tertiary);
    font-size: var(--font-down-1);
    margin-left: 0.25em;

    &:hover {
      color: var(--tertiary-high);
      text-decoration: underline;
    }
  }
}