body {
    font-family: Arial, sans-serif;
    background-color: #f9f9f9;
    color: #333;
}

nav {
    background-color: #34495e;
    color: #fff;
    padding: 10px 20px;
}

nav ul {
    list-style-type: none;
    padding: 0;
}

nav ul li {
    display: inline;
    margin-right: 10px;
}

nav ul li a {
    color: #fff;
    text-decoration: none;
    font-weight: bold;
}

nav ul li a:hover {
    color: #888;
    font-style: italic;
}

header {
    background-color: #2c3e50;
    color: #fff;
    padding: 50px 0;
    text-align: center;
}

section {
    margin: 50px 0;
    text-align: center;
}

.portfolio-item {
    margin: 20px;
    border: 1px solid #bdc3c7;
    border-radius: 10px;
    box-shadow: 5px 5px 15px rgba(0,0,0,0.1);
    transition: box-shadow 0.3s ease-in-out;
}

.portfolio-item:hover {
    box-shadow: 5px 5px 15px rgba(0,0,0,0.3);
}

.collapsible {
    background-color: #34495e;
    color: white;
    cursor: pointer;
    padding: 18px;
    width: 100%;
    border-left: 1px solid #000;
    border-right: 1px solid #000;
    border-top: 1px solid #000;
    border-top-left-radius: 5px;
    border-top-right-radius: 5px;
    border-bottom-left-radius: 5px;
    border-bottom-right-radius: 5px;
    text-align: left;
    outline: none;
    font-size: 15px;
    transition: background-color 0.3s ease-in-out;
}

.collapsible:hover, .active {
    background-color: #2c3e50;
}

.active {
    border-bottom-left-radius: 0px;
    border-bottom-right-radius: 0px;
}

.content {
    padding: 20px 20px;
    display: none;
    overflow: hidden;
    background-color: #ecf0f1;
    border-left: 1px solid #000;
    border-right: 1px solid #000;
    border-bottom: 1px solid #000;
    border-bottom-left-radius: 5px;
    border-bottom-right-radius: 5px;
}

footer {
    background-color: #34495e;
    color: #fff;
    text-align: center;
    padding: 20px 0;
}

a {
    color: #bbb;
    text-decoration: none;
}

a:hover {
    color: #2365cf;
    text-decoration: underline;
}