app.xml

<vbox id="root" w="hug, fill" h="hug, fill" gap="4" padding="8">

    <hbox id="top-bar" w="fill" h="hug" gap="4" padding="4">
        <button id="file/new" icon="test-icon" label="New" />
        <button id="file/open" icon="test-icon" label="Open" />
        <button id="file/save" icon="test-icon" label="Save" />
        <button id="file/save-as" icon="test-icon" label="Save As" />

        <spacer />;
        
        <button id="edit/copy" icon="test-icon" />
        <button id="edit/paste" icon="test-icon" />
        <button id="edit/cut" icon="test-icon" />
        <button id="edit/delete" icon="test-icon" />
    </hbox>
    
    <hbox id="main" w="fill" h="hug, fill" gap="2" padding="2">
        <vbox id="side-bar" w="hug" h="hug, fill" gap="4" padding="4">
            <button id="side/browser" icon="test-icon" />
            <button id="side/search" icon="test-icon" />
            <button id="side/git" icon="test-icon" />
            <button id="side/debug" icon="test-icon" />
            <button id="side/addons" icon="test-icon" />
            <spacer />;
            <button id="side/help" icon="test-icon" />
            <button id="side/account" icon="test-icon" />
        </vbox>
        
        <vbox id="side-content" w="360" h="hug, fill" padding="4">
            <header id="content/browser" />
        </vbox>
        
        <vbox id="content" w="fill" h="hug, fill" padding="4">
        </vbox>
    </hbox>

    <hbox id="status-bar" w="fill" h="hug" gap="4" padding="4">
        <button id="status/file" label="File" />
        <button id="status/col" label="Col" />
        <button id="status/row" label="Row" />
    </hbox>
</vbox>