Step 1 of Tutorial incomplete

When following the instructions exactly as written, the result will be a blank browser page.
Some stylesheets are missing in the starter/index.html

core-header-panel {
height: 100%;
overflow: auto;
-webkit-overflow-scrolling: touch;
}
core-toolbar {
background: #03a9f4;
color: white;
}
#tabs {
width: 100%;
margin: 0;
-webkit-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
user-select: none;
}