mastodon/app/assets/stylesheets/components.scss

.button {
  background-color: #2b90d9;

  &:hover {
    background-color: #489fde;
  }

  &:disabled {
    background-color: #9baec8;
  }
}

.icon-button {
  color: #616b86;
  cursor: pointer;

  &:hover {
    color: #717b98;
  }

  &.disabled {
    color: #535b72;
    cursor: default;
  }

  &.active {
    color: #2b90d9;
  }
}

.compose-drawer__textarea {
  background: #fff;

  &:disabled {
    background: #d9e1e8;
  }
}

.status__content, .reply-indicator__content {
  font-size: 15px;
  line-height: 20px;
  white-space: pre-wrap;
  word-wrap: break-word;
  font-weight: 300;

  a {
    color: #d9e1e8;
    text-decoration: none;

    &:hover {
      text-decoration: underline;
    }

    &.mention {
      &:hover {
        text-decoration: none;

        span {
          text-decoration: underline;
        }
      }
    }
  }
}

.reply-indicator__content {
  color: #282c37;
  font-size: 14px;

  a {
    color: #535b72;
  }
}

.status__display-name, .status__relative-time {
  text-decoration: none;
}

.status__display-name, .reply-indicator__display-name {
  &:hover {
    strong {
      text-decoration: underline;
    }
  }
}

.status__relative-time {
  &:hover {
    text-decoration: underline;
  }
}