style.css

/* make all elements a bit smaller */
body {
  zoom: 90%;
}

/* hide text from board view drop-down button */
.js-board-views-btn-container > div > button > span:nth-child(2) {
  display: none;
}

/* hide all header dividers */
.board-header-btn-divider {
  display: none;
}

/* hide text from workspace drop-down button */
.board-header-btn-org-name > .board-header-btn-text {
  display: none;
}

/* hide text from board visibility drop-down button */
.board-header-btn.perms-btn > .board-header-btn-text {
  display: none;
}

/* hide text from board menu button */
.board-header-btn.mod-show-menu > .board-header-btn-text {
  display: none;
}

.js-board-header-subscribed {
  display: none;
}

/* hide "Add List" button to prevent horizontal scrolling */
#board > .js-add-list {
  display: none;
}

/* try to display labels and members side-by-side */
.badges {
  max-width: 75% !important;
}

.list-card-members {
  float: none !important;
}

/* hide all icon badges */
.js-badges .badge,
.js-plugin-badges .hidden {
  display: none;
}

/* display custom fields line by line */
.custom-field-front-badges {
  display: block;
}

.custom-field-front-badges .badge {
  min-width: 51%;
}

/* inspired by https://github.com/webrender/trello-collapse-lists */
.js-list.collapsed {
  transform: rotate(90deg);
  transform-origin: top left;
  position: relative;
  height: 42px;
  left: 42px;
  width: 228px;
  margin-right: -182px;
}

/* hide everything in a closed list... */
.js-list.collapsed .list * {
  display: none !important;
}

/* ...except for the title and the collapse toggle */
.js-list.collapsed .list .list-header,
.js-list.collapsed .list .list-header-name,
.js-list.collapsed .list .collapse-toggle {
  display: block !important;
}

/* we need to reduce the width of the title to fit the collapse toggle in */
.js-list .list .list-header-name {
  width: calc(100% - 25px);
}

.ui-draggable-dragging {
  display: none !important;
}

/* collapse toggle button */
.collapse-toggle {
  float: left;
  cursor: pointer;
  background: white;
  border: 1px solid #ccc;
  border-radius: 50%;
  height: 20px;
  width: 20px;
  text-align: center;
  position: relative;
  margin-left: 2px;
}

/* collapse toggle button - triangle */
.collapse-toggle:after {
  display: block;
  content: "";
  width: 0;
  height: 0;
  border-left: 5px solid transparent;
  border-right: 5px solid transparent;
  border-top: 5px solid #000;
  position: absolute;
  top: 8px;
  left: 5px;
}