zotero/scss/elements/_attachmentsBox.scss

attachments-box {
	display: flex;
	flex-direction: column;

	&[hidden] {
		display: none;
	}

	.head {
		.togglePreview {
			display: none;
		}
	
		&:hover {
			.togglePreview {
				display: unset;
			}
		}
	}

	&[data-use-preview] {
		.togglePreview {
			@include svgicon-menu('preview-hide', 'universal', '16');
		}
	}

	&:not([data-use-preview]),
	& > collapsible-section[empty] {
		attachment-preview {
			visibility: hidden;
			display: none;
		}

		.togglePreview {
			@include svgicon-menu('preview-show', 'universal', '16');
		}
	}
	
	& > collapsible-section > .body {
		display: flex;
		flex-direction: column;

		attachment-preview {
			opacity: 1;
	
			&[data-preview-status=fail] {
				display: none;
				opacity: 0;
	
				.icon {
					opacity: 0;
				}
			}
	
			&[data-preview-status=loading] {
				opacity: 0;
			}
		}

		.attachments-container {
			padding-left: 12px;
			display: flex;
			flex-direction: column;

			@include comfortable {
				gap: 4px;
			}
		}
	}
}