styles.css

.iframe-wrapper {
	position: relative;
	margin-top: 1rem;
	margin-bottom: 1rem;
}
.iframe-header {
	display: grid;
	align-items: end;
	height: 40px;
}
.iframe-title {
	margin-left: 8px;
}
.iframe-togglesize-btn {
	position: absolute;
	top: 0;
	right: 0;
}
.iframe-copiki, .iframe-fullsize-dummy {
	border: 3px solid #e2e2e2;
	border-radius: 8px;
	overflow: auto;
	resize: vertical;
	min-height: 200px;
}
.iframe-copiki {
	transition: all .5s ease;
}

.iframe-fullsize {
	position: fixed;
	top: 0;
	left: 0;
	bottom: 0;
	right: 0;
	width: 100%;
	height: 100%; 
	margin: 0;
	padding: 5px;
	overflow: hidden;
	z-index: 999999;

	background: rgba(255, 255, 255, .9);
	
	transition: all .5s ease;
}
.iframe-fullsize .iframe-copiki {
	width: 100%;
	height: calc(100vh - 50px) !important;
	resize: none;
}
.iframe-fullsize .iframe-togglesize-btn {
    top: 5px;
    right: 5px;
}