Update: Updated gtk theme and added gitignore.

usr/share/themes/gtk-dark-keyitdev/metacity-1/titlebuttons/titlebutton-unshade-backdrop.svg

@@ -0,0 +1,63 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   width="16"
+   height="16"
+   version="1.1"
+   id="svg11"
+   sodipodi:docname="titlebutton-unshade-backdrop.svg"
+   inkscape:version="1.1.2 (0a00cf5339, 2022-02-04)"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:svg="http://www.w3.org/2000/svg">
+  <defs
+     id="defs15" />
+  <sodipodi:namedview
+     id="namedview13"
+     pagecolor="#505050"
+     bordercolor="#eeeeee"
+     borderopacity="1"
+     inkscape:pageshadow="0"
+     inkscape:pageopacity="0"
+     inkscape:pagecheckerboard="0"
+     showgrid="false"
+     inkscape:zoom="36.375"
+     inkscape:cx="8"
+     inkscape:cy="8"
+     inkscape:window-width="1920"
+     inkscape:window-height="1012"
+     inkscape:window-x="0"
+     inkscape:window-y="0"
+     inkscape:window-maximized="1"
+     inkscape:current-layer="svg11" />
+  <path
+     d="m 8.0001,15.000015 c 3.8659,0 6.9999,-3.134 6.9999,-7.0000004 0,-3.866 -3.134,-7 -6.9999,-7 -3.866,0 -7.0001,3.134 -7.0001,7 0,3.8660004 3.134,7.0000004 7.0001,7.0000004"
+     fill="#5d5d5d"
+     id="path2"
+     style="fill:#414868;fill-opacity:1" />
+  <g
+     id="titlebutton-minimize-backdrop"
+     transform="matrix(1 0 0 -1 -253 -252.64)">
+    <rect
+       x="253"
+       y="-268.64"
+       width="16"
+       height="16"
+       ry="1.6931e-5"
+       opacity="0"
+       stroke-width=".47432"
+       style="paint-order:markers stroke fill"
+       id="rect4" />
+    <g
+       transform="translate(254,-267.64)"
+       enable-background="new"
+       id="g6" />
+  </g>
+  <path
+     d="M 8,11.500015 6,8.5000146 h 1 v -4 h 2 v 4 h 1 z"
+     color="#000000"
+     fill="#000000"
+     opacity="0.5"
+     style="text-indent:0;text-decoration-line:none;text-transform:none"
+     id="path9" />
+</svg>