body {
    font-family: Arial, sans-serif;
}
header {
    width: 100%;
    box-shadow: 0px 2px 5px rgba(0, 0, 0, .2);
}
.sidebar {
    height: 100vh;
    width: 250px;
    position: fixed;
    top: 0;
    left: 0;
    background-color: #343a40;
    color: #fff;
    transition: all 0.3s ease;
}

.sidebar.collapsed {
    width: 80px;
}

.sidebar a {
    color: #adb5bd;
    text-decoration: none;
    padding: 10px 15px;
    display: block;
    transition: all 0.3s ease;
}

.sidebar a:hover {
    background-color: #495057;
    color: #fff;
}

.sidebar h2 {
    font-size: 1.5rem;
    text-align: center;
    padding: 15px 0;
    margin: 0;
    transition: all 0.3s ease;
}

.sidebar.collapsed h2 {
    font-size: 1rem;
}

.sidebar.collapsed a {
    text-align: center;
}

.content {
    margin-left: 250px;
    transition: all 0.3s ease;
}

.content.collapsed {
    margin-left: 80px;
}

.toggle-btn {
    background-color: #343a40;
    color: #fff;
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.3s ease;
    cursor: pointer;
}