Q:

How can I hide or diminish VS2017's vertical lines in the editor

Visual Studio 2017 uses quite bright, dashed, vertical lines within code's indentation to highlight the extent of various scopes.

How can I turn these off, or make them less vivid?

A:

You can reduce the intensity of these lines:

In VS2017, go to menu Tools, Options....
Navigate to Environment/Fonts and Colors and scroll to select the Structure Guide Lines display item.

Click custom, then drag down the black arrow to the right of the dialog until you see a colour you like.

A:

You can also turn them off completely from Tools\Options, Text Editor, General, Show structure guide lines.

