Invoices in view mode look strange

2

Check your custom theme, make sure to set body style min-width to 800px;

/* BODY STYLES - Main document styling */
		body {
			margin: 0;
			padding: 30px; /* Space around document content */
			font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; /* Change font family here */
			color: #171717; /* Main text color */
			font-size: 12px; /* Base font size for document */
			line-height: 1.428571429;
			min-width: 800px; /* Minimum width to prevent layout breaking */
		}