Custom CSS, hide the Vivaldi titlebar when fullscreen, Windows Version

custom.css

/* Hide the Vivaldi titlebar when maximised, Windows Version */
/* Intended for use with tab position being on the left or right */
/* @import "custom.css"; */
/* resources\vivaldi\style\common.css */

/* Remove header */
:-webkit-any(.native, .maximized)#browser #header {
    min-height: 0 !important;
}

/* Demolish Vivaldi button */
:-webkit-any(.native, .maximized)#browser .vivaldi  {
	display: none !important;
}

/* Keep horizontal menu */
:-webkit-any(.native, .maximized)#browser .topmenu {
    position: absolute;
}

/* Reduce toolbar size for vivialdi button */
:-webkit-any(.native, .maximized)#browser:not(.tabs-top) .toolbar.toolbar-addressbar {
    padding-left: 24px;
}

/* Reduce toolbar size for horizontal menu */
:-webkit-any(.native, .maximized).horizontal-menu#browser:not(.tabs-top) .toolbar.toolbar-addressbar {
    padding-left: 267px;
}

/* Non-Native window fixes */

/* Keep window buttons */
.maximized#browser .window-buttongroup {
    display: none !important;
}

/* Reduce toolbar size for window buttons */
.maximized#browser:not(.native):not(.tabs-top) .toolbar.toolbar-addressbar {
    padding-right: 140px;
}

/* Adjust horizontal menu position */
.maximized#browser:not(.native) .topmenu {
    left: -30px;
}

/* Remove vivaldi button, horizontal menu and window buttons when no ui */
.maximized.minimal-ui#browser :-webkit-any(.vivaldi, .topmenu, .window-buttongroup) {
    display: none !important;
}

/* Tabs on top fixes */

/* Maximized not Native - Reduce tab bar size for horizontal menu and window buttons */
.maximized.horizontal-menu#browser:not(.native) #tabs-container.top {
    padding-left: 276px !important;
    padding-right: 140px !important;
}

/* Native - Reduce tab bar size for horizontal menu and window buttons */
.native.horizontal-menu#browser #tabs-container.top {
    padding-left: 276px !important;
}

/* Remove coloured bar
.toolbar-addressbar:after {
    display: none !important;
}     */

I don't understand. My toolbar is already hidden in Fullscreen mode.
I am looking for something that will show the toolbar + address bar in Fullscreen when you hover mouse to top of screen.

My apologies, the wording in the comment was wrong, this wont work for what you want. This script hides the title bar when vivaldi is maximised.

In full screen mode you can use CTRL + L to bring up the address bar, and use hotkeys for the rest (ctrl + F1 will bring up a searchable list)