teemant-old/src/script/theme.js

function swapSheet(name) {
	document.querySelector('#theme_stylesheet').setAttribute('href', 'style/'+name+'.css');
}

const themes = module.exports = {
	available: {
		default: {
			name: 'Default',
			type: 'bright',
			nick_pallete: {
				H: [1, 360],
				S: [30, 100],
				L: [30, 70]
			},
			stylesheet: 'theme_default',
			default: true,
			colorSamples: {
				toolbar: '#00c7e0',
				background: '#f5f5f5'
			}
		},

		night: {
			name: 'Night',
			type: 'dark',
			nick_pallete: {
				H: [1, 360],
				S: [30, 100],
				L: [50, 100]
			},
			stylesheet: 'theme_night',
			default: false,
			colorSamples: {
				toolbar: '#008e8e',
				background: '#1d1d1d'
			}
		}
	},

	change_theme: function(name) {
		if(name in themes.available) {
			swapSheet(themes.available[name].stylesheet);
			window.irc.config.theme = name;
		}
	}
};