Caption and Image alignment

I have made my own child theme with my own css. I have an image that I wish to align right. If I use this code without captions it works correctly.<img src="https://meliolegbag.com/wp-content/uploads/2015/04/MattPearceCEOAlbertMedical.jpg" alt="Dr. Matt Pearce, CEO of Albert Medical - the makers of Melio Leg Bag System" width="384" height="422" class="size-full wp-image-642" align="right" />

But if I use this code with captions it doesnt align.
[caption id="attachment_642" align="alignright" width="384"]<a href="https://meliolegbag.com/wp-content/uploads/2015/04/MattPearceCEOAlbertMedical.jpg"><img src="https://meliolegbag.com/wp-content/uploads/2015/04/MattPearceCEOAlbertMedical.jpg" alt="Dr. Matt Pearce, CEO of Albert Medical - the makers of Melio Leg Bag System" width="384" height="422" class="size-full wp-image-642" /></a> Dr. Matt Pearce, CEO of Albert Medical - the makers of Melio Leg Bag System[/caption]
I read that maybe my custom style sheets may be missing the correct classes so I copied this code from the wordpress site yet it still does not work can anyone help?

.alignnone {
    margin: 5px 20px 20px 0;
}

.aligncenter,
div.aligncenter {
    display: block;
    margin: 5px auto 5px auto;
}

.alignright {
    float:right;
    margin: 5px 0 20px 20px;
}

.alignleft {
    float: left;
    margin: 5px 20px 20px 0;
}

a img.alignright {
    float: right;
    margin: 5px 0 20px 20px;
}

a img.alignnone {
    margin: 5px 20px 20px 0;
}

a img.alignleft {
    float: left;
    margin: 5px 20px 20px 0;
}

a img.aligncenter {
    display: block;
    margin-left: auto;
    margin-right: auto
}

.wp-caption {
    background: #fff;
    border: 1px solid #f0f0f0;
    max-width: 96%; /* Image does not overflow the content area */
    padding: 5px 3px 10px;
    text-align: center;
}

.wp-caption.alignnone {
    margin: 5px 20px 20px 0;
}

.wp-caption.alignleft {
    margin: 5px 20px 20px 0;
}

.wp-caption.alignright {
    margin: 5px 0 20px 20px;
}

.wp-caption img {
    border: 0 none;
    height: auto;
    margin: 0;
    max-width: 98.5%;
    padding: 0;
    width: auto;
}

.wp-caption p.wp-caption-text {
    font-size: 11px;
    line-height: 17px;
    margin: 0;
    padding: 0 4px 5px;
}

/* Text meant only for screen readers. */
.screen-reader-text {
	clip: rect(1px, 1px, 1px, 1px);
	position: absolute !important;
	height: 1px;
	width: 1px;
	overflow: hidden;
}

.screen-reader-text:focus {
	background-color: #f1f1f1;
	border-radius: 3px;
	box-shadow: 0 0 2px 2px rgba(0, 0, 0, 0.6);
	clip: auto !important;
	color: #21759b;
	display: block;
	font-size: 14px;
	font-size: 0.875rem;
	font-weight: bold;
	height: auto;
	left: 5px;
	line-height: normal;
	padding: 15px 23px 14px;
	text-decoration: none;
	top: 5px;
	width: auto;
	z-index: 100000; /* Above WP toolbar. */
}