Add UXML and USS

[Svarshick]

UXML+USS are markup and sheet languages for the Unity Game Engine (like HTML+CSS)

1. UXML is inspired by HTML, XAML and XML
2. USS is similar to CSS

File extensions

1. UXML : .uxml
2. USS : .uss

[AlDanial]

Can you point me to small UXML and USS files with various comments that I can use for the test suite?

[Svarshick]

Unfortunately, I couldn't find any official UXML/USS examples with comments., so I created some simple ones

1. UXMl example

<ui:UXML xmlns:ui="UnityEngine.UIElements" xmlns:uie="UnityEditor.UIElements" editor-extension-mode="False">
    <!-- Importing styles from uss file -->
    <Style src="project://database/Assets/UI/Resources/common.uss?fileID=7433441132597879392&amp;guid=c5fd8770b48bac1e48d6087c0a2e0230&amp;type=3#common" />
    <!-- Instantiating build-in control (Button) -->
    <ui:Button text="Choose me" name="choice" />
</ui:UXML>

2. USS example

/* name selector (like ID selector in CSS) */
#root {
    /* 
    some style
    this is an example of a multiline comment 
    */
}

/* class selector (like in CSS) */
.hidden {
    display: none;
}