VS code common dark theme with neon highlights

vscode_dark++.css

.mtk13 {
    color: #9cdcfe;
    text-shadow: 0 0 2px #100c0f, 0 0 5px #ffdda926, 0 0 10px #fff3;
}

.mtk12 {
    color: #ffdda9;
    text-shadow: 0 0 2px #100c0f, 0 0 5px #ffdda926, 0 0 10px #fff3;
}

.mtk15 {
    color: #e67ede;
}

.mtk11  {
    color: #4ec9b0;
    text-shadow: 0 0 2px #100c0f, 0 0 5px #38a992, 0 0 10px #fff3;
}

.mtk5 {
    color: #48abff;
    text-shadow: 0 0 2px #000, 0 0 10px #48abff6b, 0 0 5px #48abff85, 0 0 25px #48abff52;
}

.mtk16 {
    color: #c586c0;
    letter-spacing: -0.4px;
    font-weight: 500;
}

.panel-header {
    background-color: rgba(106, 95, 134, 0.2) !important;
}

#workbench.parts.sidebar {
    background: rgb(25, 25, 25) !important;
}

div#workbench.parts.sidebar {}

.part.sidebar.left {
    background-color: rgb(25, 25, 25) !important;
}

.part.activitybar.left {
    background-color: rgb(19, 19, 19) !important;
}

.monaco-workbench {
    background-color: #1d1d1d;
}

.monaco-list .monaco-list-row.selected {
    background-color: rgba(138, 138, 138, 0.2);
}


.monaco-workbench .part.statusbar {
    background-color: rgb(100, 50, 125) !important;
}

.cdr.squiggly-error:after {
    content: '';
    position: absolute;
    height: 100%;
    width: 100%;
    background: #a52e2e;
    filter: blur(10px);
}

.monaco-editor .view-overlays .current-line {
    background: #1f1f1f;
    transform: translateY(-3px);
    background: #1b1b1b;
    height: 25px !important;
    z-index: -1;
}

.showUnused .monaco-editor .squiggly-inline-unnecessary {
    opacity: 0.8;
    filter: contrast(0.7);
}

Hi, Where to add this code ? thanks

@kanta-mir
https://dev.to/js2me/make-your-own-custom-theme-for-vs-code-me7