zotero/scss/elements/_itemPaneHeader.scss

item-pane-header {
	&:not([hidden]) {
		display: flex;
	}
	flex-direction: column;
	align-items: stretch;
	padding: 8px;
	border-bottom: 1px solid var(--fill-quinary);
	
	max-height: 25%;
	overflow-y: auto;
	scrollbar-color: var(--color-scrollbar) var(--color-scrollbar-background);

	.head-container {
		display: flex;
		flex-direction: column;
		align-items: center;
		justify-content: space-between;

		@include compact {
			gap: 4px;
		}

		@include comfortable {
			gap: 8px;
		}

		.title-head {
			align-self: stretch;

			.title {
				margin-top: calc(0px - var(--editable-text-padding-block));
				flex: 1 1 0;
				font-weight: 600;
				line-height: 1.333;
				
				editable-text {
					flex: 1;
				}
			}
			
			.creator-year {
				color: var(--fill-secondary);
			}
			
			.bib-entry {
				line-height: 1.5;
				
				&.loading {
					color: var(--fill-secondary);
				}
			}
			
			.creator-year, .bib-entry {
				// Set padding to match editable-text in tight mode, plus 1px for border
				padding-inline: calc(var(--editable-text-tight-padding-inline) + 1px);
				overflow-wrap: anywhere;
			}
		}

		.custom-head {
			display: flex;
			flex-direction: row;
			align-self: stretch;
			gap: 8px;

			@media (-moz-platform: macos) {
				// The extent of the button is about 2px wider than its optical width
				// need to compensate for that
				gap: 4px;
			}

			&:empty {
				display: none;
			}

			button {
				// Allow the button to grow/shrink to fit the container
				width: 0;
				margin: 0;
				flex-grow: 1;

				padding: 2px 6px;

				@media (-moz-platform: macos) {
					height: 24px;
					padding: 3px 0px 1px 0px;

					&:is(.split-menu-button) {
						padding: 3px 2px 1px 3px;
					}
				}

				.button-text {
					width: 0;
					flex-grow: 1;
					justify-content: center;

					&::before {
						overflow: hidden;
						white-space: nowrap;
						text-overflow: ellipsis;
					}
				}

				&:is(.no-shrink-button) {
					width: auto;
					flex-shrink: 0;

					.button-text {
						width: auto;
					}
				}
			}
		}
	}

	&.no-title-head {
		&:not(.has-custom-head) {
			padding: 0;
			border: none;
		}

		.title-head {
			display: none;
		}
	}
}