app.css

/* Hide components */
[data-testid="DMDrawer"],
[data-testid="SideNav_NewTweet_Button"],
[data-testid="retweet"] > div span,
[data-testid="unretweet"] > div span,
[data-testid="like"] > div span,
[data-testid="unlike"] > div span,
[data-testid="reply"] > div span,
[data-testid="socialContext"],
[data-testid="SideNav_AccountSwitcher_Button"] > div svg {
  display: none !important;
}

/* Hide right column but first section */
[data-testid="sidebarColumn"]
  > div
  > div:last-child
  > div
  > div
  > div
  > div:not(:first-child) {
  display: none;
}

/* Desktop view */
@media (min-width: 1280px) {
  /* Set primary nav to have 20% width */
  nav[aria-label="Primary"] {
    max-width: 20%;
  }

  /* Hide trending link on left column */
  [data-testid="AppTabBar_Explore_Link"] {
    display: none !important;
  }
}

/* Hide nav menu item labels */
nav[aria-label="Primary"] > a > div > div + div,
[data-testid="AppTabBar_More_Menu"] > div > div + div {
  display: none;
}

/* Hide search input placeholder */
[data-testid="SearchBox_Search_Input"]::-webkit-input-placeholder {
  color: transparent !important;
}

[data-testid="SearchBox_Search_Input"]::-moz-placeholder {
  color: transparent !important;
}

[data-testid="SearchBox_Search_Input"]:-ms-input-placeholder {
  color: transparent !important;
}

[data-testid="SearchBox_Search_Input"]:-moz-placeholder {
  color: transparent !important;
}

[data-testid="SearchBox_Search_Input"]::placeholder {
  color: transparent !important;
}