ar-design/dist/assets/css/components/feedback/modal/header.css

AR Design is a (react | nextjs) ui library.

.ar-modal-wrapper > .ar-modal > .header {
  display: flex;
  flex-direction: row;
  justify-content: space-between;
  align-items: center;
  height: 3.5rem;
  padding: 0 2rem;
  border-bottom: solid 1px var(--gray-200);
}
.ar-modal-wrapper > .ar-modal > .header > .ar-typography-title {
  width: calc(100% - 2.75rem);
  text-wrap: nowrap;
  text-overflow: ellipsis;
  overflow: hidden;
}

.ar-modal-wrapper > .ar-modal > .header .close {
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: var(--white);
  min-width: 2rem;
  min-height: 2rem;
  border: solid 1px var(--gray-300);
  border-radius: var(--border-radius-sm);
  cursor: pointer;
  user-select: none;
  transition: background 250ms, border 250ms ease-in-out;
}
.ar-modal-wrapper > .ar-modal > .header .close::before,
.ar-modal-wrapper > .ar-modal > .header .close::after {
  position: absolute;
  content: "";
  width: 2px;
  height: 15px;
  background-color: var(--gray-300);
  transform-origin: center;
  transform: rotate(-45deg);
  transition: transform 250ms ease-in-out;
}
.ar-modal-wrapper > .ar-modal > .header .close::after {
  transform: rotate(45deg);
}
.ar-modal-wrapper > .ar-modal > .header .close:hover {
  background-color: rgba(var(--danger-rgb), 0.1);
  border: solid 1px var(--danger);
  color: rgba(var(--danger-rgb), 0.75);
}
.ar-modal-wrapper > .ar-modal > .header .close:hover::before,
.ar-modal-wrapper > .ar-modal > .header .close:hover::after {
  background-color: var(--danger);
  transform: rotate(45deg);
}
.ar-modal-wrapper > .ar-modal > .header .close:hover::after {
  transform: rotate(-45deg);
}