* {
    margin: 0;
    padding: 0; 
}

html {
    background-color: white;
}

body {
	font-family: Arial, Helvetica, sans-serif;
    font-size: 100%;
    width: auto;
    margin: 0 auto;
}

a:focus, a:hover {
    text-decoration: underline;
}

header {
    padding-top: 10px;
    padding-bottom: 50px;
    background-color:#005A8B;
    height: 15px;
}

header img {
	float:left;
    padding-top: 0;
    padding-left: 10px;
}

#nav_menu ul li a:hover {
    text-decoration: underline;
    font-size: 110%
}

#nav_menu ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    position: relative;
    float: left;
}

#nav_menu ul li {
    float: left;
}

#nav_menu ul li a {
    display: block;
    width: 100px;
    padding: 0.5em 0em;
    margin-left: 4em;
    margin-right: 4em;
    text-decoration: none;
    color: white;
    font-weight: bold;
}

#nav_menu ul li a.alpha:hover {
    text-decoration: none;
    font-size: 95%;
}

#nav_menu a.alpha {
    color:  white;
    text-align: left;
    padding-left: 70px;
    padding-top: 10px;
    width: 200px;
    margin-left: 2em;
    font-size: 95%
}

#nav_menu ul ul {
    display: none;
    position: absolute;
    top: 100%;
    background-color: #005A8B;
}

#nav_menu ul ul li {
    float: none;
}

#nav_menu ul li:hover > ul {
    display: block;
}

#nav_menu ul::after {
    content: "";
    clear: both;
    display: block;
}

#nav_menu ul ul {
    display: none;
    position: absolute;
    top: 100%;
}

#nav_menu ul ul li {
    float: none;
}

#nav_menu ul li:hover > ul {
    display: block;
}

#nav_menu ul::after {
    content: "";
    clear: both;
    display: block;
}

main {
	clear: left;
}

p.beta1 {
    border: 3px solid black;
    margin-top: 5%;
    margin-left: 15%;
    height: 300px;
    width: 19%;
    border-radius: 100%;
    padding: 10px 20px;
    float: left;
    background-image: url(Images/Peng_Xu.jpg);
    background-repeat: no-repeat;
    background-size: cover;
}

section.beta1 {
    margin-top: 4%;
    margin-right: 10%;
    margin-bottom: 5%;
    width: 600px;
    text-align: left;
    color: black;
    padding: 40px;
    font-family: cursive;
    font-size: 159%;
    float: right;
}

section.beta1 ul, section.beta2 ul, section.beta3 ul, section.beta4 ul {
    list-style-type: none;
}

p.beta2 {
    border: 3px solid black;
    margin-top: 5%;
    margin-left: 15%;
    height: 300px;
    width: 19%;
    border-radius: 100%;
    padding: 10px 20px;
    float: left;
    background-image: url(Images/Andy_Du.jpg);
    background-repeat: no-repeat;
    background-size: cover;
}

section.beta2 {
    margin-top: 1%;
    margin-right: 10%;
    margin-bottom: 5%;
    width: 600px;
    text-align: left;
    color: black;
    padding: 40px;
    font-family: cursive;
    font-size: 159%;
    float: right;
}

section.beta2 ul li a:hover {
    font-style: italic;
}

p.beta3 {
    border: 3px solid black;
    margin-top: 5%;
    margin-left: 15%;
    height: 300px;
    width: 19%;
    border-radius: 100%;
    padding: 10px 20px;
    float: left;
    background-image: url(Images/Roger_Blake.jpg);
    background-repeat: no-repeat;
    background-size: cover;
}

section.beta3 {
    margin-top: 2%;
    margin-right: 10%;
    margin-bottom: 5%;
    width: 600px;
    text-align: left;
    color: black;
    padding: 40px;
    font-family: cursive;
    font-size: 159%;
    float: right;
}

p.beta4 {
    border: 3px solid black;
    margin-top: 5%;
    margin-left: 15%;
    height: 300px;
    width: 19%;
    border-radius: 100%;
    padding: 10px 20px;
    float: left;
    background-image: url(Images/Jonathan_Kim.jpg);
    background-repeat: no-repeat;
    background-size: cover;
}

section.beta4 {
    margin-top: 2%;
    margin-right: 10%;
    margin-bottom: 5%;
    width: 600px;
    text-align: left;
    color: black;
    padding: 40px;
    font-family: cursive;
    font-size: 159%;
    float: right;
}

.empty {
    height: 150px;
    width: 100%;
    float: left;
}

footer {
    margin-top: 99px;
    background-color:#005A8B;
    clear: both;
    height: 70px;
}

footer p {
    text-align: center;
    color: white;
    padding: 1em 0;
}

.breadcrumb {
    margin-left: 2em; 
    margin-top: 1em; 
    font-size: 130%;
    color: #005A8B;
    text-decoration: none;  
}
.breadcrumb a {
    color: #005A8B;
}
#link1 {
    font-weight: bold;
    color: #4d4d4d
}

#home {
    text-decoration: none
}
#home:hover {
    text-decoration: underline;  
}