styles.css

html, body, main {
	width: 100%;
	height: 100%;
	padding: 0;
	margin: 0;
}
main {
	display: flex;
}
#editor {
    height: 100%;
	flex-grow: 1;
}
#project-tree {
    height: 100%;
    box-sizing: border-box;
	background-color: #EEE;
	padding: 0.5em;
    overflow: auto;
    overflow-x: initial;
    overflow-y: auto;
    font-family: monospace;
}

.fs-file-item, .fs-directory-item {
	display: block;
}
.fs-file-item::before {
	content: "\25A2 ";
}
.fs-directory-item+*{
	display: none;
}
.fs-directory-item.active+*{
	display: block;
}
.fs-directory-item::before {
	content: "\25BA ";
}
.fs-directory-item.active::before {
	content: "\25BC ";
}