* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f5f5f5;
    color: #333;
}

.container {
    display: flex;
    min-height: 100vh;
}

/* Sidebar Styling */
.sidebar {
    width: 250px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
    box-shadow: 2px 0 10px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease;
    z-index: 1000;
}

.sidebar.collapsed {
    transform: translateX(-100%);
}

.reopen-btn {
    display: none;
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 1001;
    background: #667eea;
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 18px;
    line-height: 1;
}

.sidebar.collapsed ~ .reopen-btn {
    display: block;
}

.logo {
    margin-bottom: 40px;
    text-align: center;
    border-bottom: 2px solid rgba(255, 255, 255, 0.3);
    padding-bottom: 20px;
}

.logo h2 {
    font-size: 24px;
    font-weight: 600;
}

.nav-menu {
    list-style: none;
}

.nav-menu li {
    margin: 15px 0;
}

.nav-menu button {
    background: none;
    border: none;
    color: white;
    font-size: 16px;
    cursor: pointer;
    width: 100%;
    text-align: left;
    padding: 12px 15px;
    border-radius: 5px;
    transition: all 0.3s ease;
}

.nav-menu button:hover {
    background-color: rgba(255, 255, 255, 0.2);
    padding-left: 25px;
}

.nav-menu button.active {
    background-color: rgba(255, 255, 255, 0.3);
    border-left: 3px solid #fff;
    padding-left: 12px;
}

.sidebar-footer {
    position: absolute;
    bottom: 20px;
    width: calc(100% - 40px);
}

.toggle-btn {
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.5);
    padding: 10px 15px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 14px;
    width: 100%;
    transition: all 0.3s ease;
}

.toggle-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    border-color: white;
}

/* Main Content Area */
.main-content {
    margin-left: 250px;
    padding: 40px;
    flex: 1;
    transition: margin-left 0.3s ease;
}

.sidebar.collapsed ~ .main-content {
    margin-left: 0;
}

/* Cards Section */
.section-title {
    margin-bottom: 40px;
    text-align: center;
}

.section-title h1 {
    font-size: 36px;
    margin-bottom: 10px;
    color: #333;
}

.section-title p {
    font-size: 16px;
    color: #666;
}

.cards-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.card {
    background: white;
    border-radius: 10px;
    padding: 30px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    cursor: pointer;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

.card h3 {
    font-size: 22px;
    margin-bottom: 15px;
    color: #667eea;
}

.card p {
    font-size: 14px;
    color: #666;
    margin-bottom: 20px;
    line-height: 1.6;
}

.card-link {
    display: inline-block;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 10px 20px;
    border-radius: 5px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

.card-link:hover {
    background: linear-gradient(135deg, #764ba2 0%, #667eea 100%);
    transform: scale(1.05);
}

/* Content Section */
.content-section {
    animation: fadeIn 0.3s ease;
}

.back-btn {
    background: #667eea;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 14px;
    margin-bottom: 30px;
    transition: all 0.3s ease;
}

.back-btn:hover {
    background: #764ba2;
    transform: translateX(-5px);
}

.content-body {
    background: white;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    line-height: 1.8;
}

.content-body h2 {
    color: #667eea;
    margin-bottom: 20px;
    font-size: 28px;
}

.content-body p {
    color: #666;
    font-size: 16px;
    margin-bottom: 15px;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .sidebar {
        width: 200px;
    }

    .main-content {
        margin-left: 200px;
        padding: 20px;
    }

    .sidebar.collapsed ~ .main-content {
        margin-left: 0;
    }

    .cards-container {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .section-title h1 {
        font-size: 28px;
    }

    .content-body {
        padding: 20px;
    }
}

@media (max-width: 480px) {
    .sidebar {
        width: 100%;
        height: auto;
        position: relative;
        transform: none;
    }

    .sidebar.collapsed {
        transform: none;
    }

    .main-content {
        margin-left: 0;
        padding: 15px;
    }

    .logo {
        margin-bottom: 20px;
    }

    .nav-menu {
        display: flex;
        gap: 10px;
        flex-wrap: wrap;
    }

    .nav-menu li {
        flex: 1;
        min-width: 150px;
        margin: 5px 0;
    }

    .sidebar-footer {
        position: static;
        width: auto;
        margin-top: 20px;
    }

    .section-title h1 {
        font-size: 22px;
    }

    .card {
        padding: 20px;
    }
}