style.css

       /* Dark Theme Variables */
       :root {
        --primary: #6a00ff;
        --secondary: #00e5ff;
        --accent: #ff00aa;
        --dark: #0a0a20;
        --darker: #050510;
        --light: #e0f7fa;
        --gray: #a0a0c0;
        --success: #00ffaa;
        --warning: #ffcc00;
        --danger: #ff5555;
        --dark-gray: #303050;
        --medium-gray: #707090;
        --light-gray: #c0c0e0;
        --white: #ffffff;
        
        --sidebar-width: 280px;
        --header-height: 70px;
        --border-radius: 8px;
        --transition: all 0.3s ease;
        --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
        --widget-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    }

    /* Light Theme Variables */
    body.light-theme {
        --dark: #f5f5ff;
        --darker: #e0e0f0;
        --light: #1a1a2e;
        --gray: #606080;
        --dark-gray: #d0d0e0;
        --medium-gray: #9090b0;
        --light-gray: #303050;
        --white: #0a0a20;
    }

    body.light-theme .resource-card,
    body.light-theme .resources-section,
    body.light-theme .challenge-banner,
    body.light-theme .sidebar,
    body.light-theme header,
    body.light-theme .user-dropdown {
        background-color: var(--dark);
        border-color: rgba(0, 0, 0, 0.1);
    }

    * {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
        font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    }

    html {
        scroll-behavior: smooth;
    }

    body {
        background-color: var(--darker);
        color: var(--light);
        min-height: 100vh;
        position: relative;
        overflow-x: hidden;
        transition: background-color 0.3s ease, color 0.3s ease;
    }

    /* Header */
    header {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: var(--header-height);
        background-color: var(--dark);
        box-shadow: var(--box-shadow);
        display: flex;
        justify-content: space-between;
        align-items: center;
        padding: 0 25px;
        z-index: 100;
        transition: var(--transition);
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }

    .logo {
        display: flex;
        align-items: center;
        gap: 12px;
    }

    .logo img {
        height: 36px;
        width: auto;
    }

    .logo h1 {
        font-size: 1.4rem;
        font-weight: 700;
        color: var(--primary);
    }

    .menu-toggle {
        background: none;
        border: none;
        color: var(--white);
        font-size: 1.4rem;
        cursor: pointer;
        display: none;
        width: 40px;
        height: 40px;
        align-items: center;
        justify-content: center;
        border-radius: var(--border-radius);
        transition: var(--transition);
    }

    .menu-toggle.active {
        background: rgba(106, 0, 255, 0.2);
        transform: rotate(90deg);
    }

    .user-menu {
        display: flex;
        align-items: center;
        gap: 20px;
    }

    .notification {
        position: relative;
        cursor: pointer;
    }

    .notification i {
        font-size: 1.2rem;
        color: var(--medium-gray);
    }

    .notification-badge {
        position: absolute;
        top: -5px;
        right: -5px;
        background-color: var(--danger);
        color: white;
        border-radius: 50%;
        width: 18px;
        height: 18px;
        display: flex;
        justify-content: center;
        align-items: center;
        font-size: 0.7rem;
        font-weight: bold;
    }

    .user-avatar {
        width: 40px;
        height: 40px;
        border-radius: 50%;
        background-color: var(--primary);
        color: white;
        display: flex;
        justify-content: center;
        align-items: center;
        font-weight: bold;
        cursor: pointer;
        transition: var(--transition);
    }

    .user-avatar:hover {
        transform: scale(1.1);
    }

    /* Theme Toggle Styles */
    .theme-toggle {
        margin-right: 15px;
    }

    .toggle-checkbox {
        display: none;
    }

    .toggle-label {
        position: relative;
        display: block;
        width: 60px;
        height: 30px;
        background-color: var(--dark-gray);
        border-radius: 15px;
        cursor: pointer;
        transition: var(--transition);
    }

    .toggle-label i {
        position: absolute;
        top: 6px;
        font-size: 1rem;
        transition: var(--transition);
    }

    .toggle-label .fa-sun {
        left: 8px;
        color: var(--warning);
    }

    .toggle-label .fa-moon {
        right: 8px;
        color: var(--light-gray);
    }

    .toggle-ball {
        position: absolute;
        top: 3px;
        left: 3px;
        width: 24px;
        height: 24px;
        background-color: var(--white);
        border-radius: 50%;
        transition: var(--transition);
    }

    .toggle-checkbox:checked + .toggle-label {
        background-color: var(--medium-gray);
    }

    .toggle-checkbox:checked + .toggle-label .toggle-ball {
        transform: translateX(30px);
        background-color: var(--white);
    }

    .toggle-checkbox:checked + .toggle-label .fa-sun {
        color: var(--light-gray);
    }

    .toggle-checkbox:checked + .toggle-label .fa-moon {
        color: var(--primary);
    }

    /* User Dropdown */
    .user-dropdown {
        position: absolute;
        top: calc(var(--header-height) + 10px);
        right: 25px;
        background-color: var(--dark);
        border-radius: var(--border-radius);
        box-shadow: var(--box-shadow);
        width: 250px;
        padding: 15px;
        z-index: 101;
        opacity: 0;
        visibility: hidden;
        transition: var(--transition);
        border: 1px solid rgba(255, 255, 255, 0.1);
    }

    .user-dropdown.active {
        opacity: 1;
        visibility: visible;
    }

    .user-dropdown-header {
        display: flex;
        align-items: center;
        gap: 15px;
        padding-bottom: 15px;
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
        margin-bottom: 15px;
    }

    .user-dropdown-avatar {
        width: 50px;
        height: 20px;
        border-radius: 50%;
        background-color: var(--primary);
        color: white;
        display: flex;
        justify-content: center;
        align-items: center;
        font-weight: bold;
        font-size: 1.2rem;
    }

    .user-dropdown-info h3 {
        font-size: 1rem;
        margin-bottom: 5px;
        color: var(--white);
    }

    .user-dropdown-info p {
        font-size: 0.8rem;
        color: var(--medium-gray);
    }

    .user-dropdown-menu {
        list-style: none;
    }

    .user-dropdown-menu li a {
        display: flex;
        align-items: center;
        padding: 10px;
        color: var(--light-gray);
        text-decoration: none;
        border-radius: var(--border-radius);
        transition: var(--transition);
        font-size: 0.9rem;
    }

    .user-dropdown-menu li a i {
        margin-right: 10px;
        width: 20px;
        text-align: center;
        color: var(--medium-gray);
    }

    .user-dropdown-menu li a:hover {
        background-color: rgba(106, 0, 255, 0.1);
        color: var(--primary);
    }

    .user-dropdown-menu li a:hover i {
        color: var(--primary);
    }

    .user-dropdown-footer {
        margin-top: 15px;
        padding-top: 15px;
        border-top: 1px solid rgba(255, 255, 255, 0.1);
    }

    .logout-btn {
        display: flex;
        align-items: center;
        justify-content: center;
        width: 100%;
        padding: 10px;
        background-color: rgba(255, 85, 85, 0.1);
        color: var(--danger);
        border: none;
        border-radius: var(--border-radius);
        cursor: pointer;
        transition: var(--transition);
        font-size: 0.9rem;
    }

    .logout-btn i {
        margin-right: 8px;
    }

    .logout-btn:hover {
        background-color: rgba(255, 85, 85, 0.2);
    }

    /* Overlay */
    .overlay {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background-color: rgba(0, 0, 0, 0.7);
        z-index: 99;
        opacity: 0;
        visibility: hidden;
        transition: var(--transition);
    }

    .overlay.active {
        opacity: 1;
        visibility: visible;
    }

    /* Main Container */
    .main-container {
        display: flex;
        flex-direction: column;
        min-height: 100vh;
        margin-top: var(--header-height);
    }

    /* Sidebar */
    .sidebar {
        width: var(--sidebar-width);
        background-color: var(--dark);
        padding: 25px 0;
        height: calc(100vh - var(--header-height));
        position: fixed;
        left: 0;
        top: var(--header-height);
        transition: transform 0.3s ease, box-shadow 0.3s ease;
        z-index: 98;
        box-shadow: var(--box-shadow);
        overflow-y: auto;
        border-right: 1px solid rgba(255, 255, 255, 0.1);
    }

    .nav-menu {
        list-style: none;
        padding: 0;
    }

    .nav-menu li a {
        display: flex;
        align-items: center;
        padding: 12px 25px;
        color: var(--light-gray);
        text-decoration: none;
        transition: var(--transition);
        font-size: 0.95rem;
        font-weight: 500;
    }

    .nav-menu li a i {
        margin-right: 12px;
        font-size: 1.1rem;
        width: 24px;
        text-align: center;
        color: var(--medium-gray);
    }

    .nav-menu li a:hover {
        background-color: rgba(106, 0, 255, 0.1);
        color: var(--primary);
    }

    .nav-menu li a:hover i {
        color: var(--primary);
    }

    .nav-menu li a.active {
        background-color: rgba(106, 0, 255, 0.2);
        color: var(--primary);
        border-left: 3px solid var(--primary);
    }

    .nav-menu li a.active i {
        color: var(--primary);
    }

    .nav-menu li a span {
        flex-grow: 1;
    }

    /* Content Area */
    .content {
        flex: 1;
        padding: 30px;
        margin-left: var(--sidebar-width);
        transition: var(--transition);
        background-color: var(--darker);
    }

    /* Welcome Section */
    .welcome-section {
        margin-bottom: 30px;
        background-color: var(--dark);
        padding: 25px;
        border-radius: var(--border-radius);
        box-shadow: var(--widget-shadow);
        display: flex;
        justify-content: space-between;
        align-items: center;
        border: 1px solid rgba(255, 255, 255, 0.1);
    }

    .welcome-text h1 {
        font-size: 1.8rem;
        margin-bottom: 8px;
        font-weight: 700;
        color: var(--white);
    }

    .welcome-text h1 span {
        color: var(--primary);
    }

    .welcome-text p {
        color: var(--medium-gray);
        font-size: 0.95rem;
    }

    .stat-item {
        display: flex;
        align-items: center;
        gap: 10px;
        color: var(--medium-gray);
    }

    /* Challenge Banner */
    .challenge-banner {
        background: linear-gradient(135deg, var(--primary), var(--accent));
        border-radius: var(--border-radius);
        padding: 25px;
        margin-bottom: 30px;
        display: flex;
        align-items: center;
        justify-content: space-between;
        position: relative;
        overflow: hidden;
    }

    .challenge-banner::before {
        content: '';
        position: absolute;
        top: -50px;
        right: -50px;
        width: 150px;
        height: 150px;
        background: rgba(255, 255, 255, 0.1);
        border-radius: 50%;
    }

    .challenge-banner::after {
        content: '';
        position: absolute;
        bottom: -30px;
        right: 20px;
        width: 100px;
        height: 100px;
        background: rgba(255, 255, 255, 0.05);
        border-radius: 50%;
    }

    .challenge-content {
        flex: 1;
        position: relative;
        z-index: 1;
    }

    .challenge-content h3 {
        color: var(--white);
        font-size: 1.4rem;
        margin-bottom: 10px;
    }

    .challenge-content p {
        color: rgba(255, 255, 255, 0.9);
        margin-bottom: 15px;
        max-width: 600px;
    }

    .challenge-button {
        background-color: var(--white);
        color: var(--primary);
        border: none;
        border-radius: var(--border-radius);
        padding: 12px 24px;
        font-weight: 600;
        text-decoration: none;
        display: inline-flex;
        align-items: center;
        gap: 8px;
        transition: var(--transition);
        position: relative;
        z-index: 1;
    }

    .challenge-button:hover {
        transform: translateY(-2px);
        box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
        background-color: var(--light);
    }

    .challenge-button i {
        transition: var(--transition);
    }

    .challenge-button:hover i {
        transform: translateX(3px);
    }

    /* Resources Section */
    .resources-section {
        background-color: var(--dark);
        border-radius: var(--border-radius);
        padding: 30px;
        margin-bottom: 30px;
        box-shadow: var(--widget-shadow);
        border: 1px solid rgba(255, 255, 255, 0.1);
    }

    .section-header {
        margin-bottom: 30px;
    }

    .section-header h2 {
        font-size: 1.8rem;
        color: var(--white);
        margin-bottom: 10px;
    }

    .section-header p {
        color: var(--medium-gray);
        line-height: 1.6;
    }

    .resources-grid {
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
        gap: 20px;
    }

    .resource-card {
        background-color: var(--darker);
        border-radius: var(--border-radius);
        padding: 20px;
        transition: var(--transition);
        border: 1px solid rgba(255, 255, 255, 0.1);
    }

    .resource-card:hover {
        transform: translateY(-5px);
        box-shadow: var(--widget-shadow);
        border-color: var(--primary);
    }

    .resource-icon {
        width: 60px;
        height: 60px;
        background-color: rgba(106, 0, 255, 0.1);
        border-radius: 50%;
        display: flex;
        align-items: center;
        justify-content: center;
        margin-bottom: 15px;
        color: var(--primary);
        font-size: 1.5rem;
    }

    .resource-card h3 {
        color: var(--white);
        margin-bottom: 10px;
        font-size: 1.2rem;
    }

    .resource-card p {
        color: var(--medium-gray);
        margin-bottom: 15px;
        line-height: 1.6;
    }

    .resource-link {
        color: var(--primary);
        text-decoration: none;
        font-weight: 500;
        transition: var(--transition);
        display: inline-flex;
        align-items: center;
        gap: 5px;
    }

    .resource-link:hover {
        color: var(--secondary);
    }

    .resource-link i {
        transition: var(--transition);
    }

    .resource-link:hover i {
        transform: translateX(3px);
    }

    /* Responsive Styles */
    @media (max-width: 1200px) {
        .resources-grid {
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
        }
    }

    @media (max-width: 992px) {
        .sidebar {
            transform: translateX(-100%);
            width: 280px;
            z-index: 1000;
        }
        
        .sidebar.active {
            transform: translateX(0);
            box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
        }
        
        .content {
            margin-left: 0;
        }
        
        .menu-toggle {
            display: flex;
        }

        .challenge-banner {
            flex-direction: column;
            text-align: center;
            gap: 20px;
        }

        .challenge-content {
            text-align: center;
        }
    }

    @media (max-width: 768px) {
        :root {
            --header-height: 60px;
            --sidebar-width: 260px;
        }

        .resources-grid {
            grid-template-columns: 1fr 1fr;
        }

        .section-header h2 {
            font-size: 1.5rem;
        }

        .welcome-section {
            flex-direction: column;
            align-items: flex-start;
            gap: 20px;
        }
    }

    @media (max-width: 576px) {
        :root {
            --header-height: 60px;
        }
        
        header {
            padding: 0 15px;
        }
        
        .logo h1 {
            font-size: 1.2rem;
        }
        
        .logo img {
            height: 30px;
        }
        
        .content {
            padding: 20px 15px;
        }

        .resources-grid {
            grid-template-columns: 1fr;
        }

        .resource-card {
            padding: 15px;
        }
    }