youtube-music/src/plugins/music-together/style.css

.music-together-button {
  display: inline-flex;

  cursor: pointer;
  margin-left: 8px;

  & svg {
    width: 24px;
    height: 24px;
    fill: rgba(255, 255, 255, .5);
  }

  &:hover svg:hover {
    fill: #fff;
  }
}
#right-content > .music-together-divider {
  width: 1px;
  height: 26px;
  margin-left: 16px;
  margin-right: 8px;
}

.music-together-divider {
  background-color: rgba(255, 255, 255, .15);
}
.music-together-divider.horizontal {
  width: 100%;
  height: 1px;
}
.music-together-divider.vertical {
  width: 1px;
  height: 100%;
}

.music-together-tool {
  position: absolute;

  display: flex;
  align-items: center;
  gap: 8px;

  opacity: 0;
  translate: 50%;
  pointer-events: none;

  transition: all 0.225s ease-out;

  &.open {
    position: unset;
    opacity: 1;
    translate: 0;
    pointer-events: all;
  }
}

.music-together-spinner {

}

.music-together-popup {
  position: fixed;

  z-index: 1000;
}
.music-together-popup-container {
  border-radius: 10px !important;
}

.music-together-item {
  display: flex;
  height: 48px;
  align-items: center;
  padding: 0 8px;
  --iron-icon-fill-color: #fff;

  &:not([is-disabled]) {
    cursor: pointer;
  }
  &:hover {
    background-color: var(--ytmusic-menu-item-hover-background-color, rgba(255,255,255,0.05));
  }
}

.music-together-status {
  display: flex;
  flex-direction: column;
  align-items: stretch;

  padding: 16px;
}
.music-together-profile {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  overflow: hidden;
  flex-shrink: 0;
}
.music-together-profile.big {
  width: 32px;
  height: 32px;
}

.music-together-status-container {
  flex: 1;
  display: flex;
  flex-direction: row;
  align-items: flex-start;
  gap: 16px;
}
.music-together-status-item {
  display: inline-flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 4px;

  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
  font-size: 14px;
  font-weight: 400;
}
.music-together-user-container {
  display: flex;
  flex-direction: row;
  justify-content: flex-start;
  align-items: center;

  gap: 8px;
  padding-top: 16px;
  font-size: 14px;
}
.music-together-empty {
  width: 100%;

  font-size: 14px;
  color: rgba(255, 255, 255, .5);
  text-align: center;
}

.music-together-owner {
  width: 24px;
  height: 24px;
  flex-shrink: 0;
  border-radius: 50%;

  margin-left: 8px;
}

.music-together-name {
  display: none;

  color: #fff;
  font-size: 14px;
  margin-left: 8px;
}

ytmusic-player-queue-item:hover .music-together-name {
  display: unset;
}