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

body {
    display: flex;
    background-color: #f7f9fc;
    color: #333;
    scroll-behavior: smooth;
}

/* Left Navigation Bar */
.sidebar {
    width: 260px;
    height: 100vh;
    background-color: #1e293b;
    color: #fff;
    position: fixed;
    top: 0;
    left: 0;
    padding: 20px;
    display: flex;
    flex-direction: column;
    box-shadow: 4px 0 10px rgba(0,0,0,0.1);
}

.sidebar h2 {
    font-size: 1.4rem;
    margin-bottom: 30px;
    padding-bottom: 10px;
    border-bottom: 2px solid #38bdf8;
    text-align: center;
    color: #38bdf8;
}

.sidebar a {
    color: #cbd5e1;
    text-decoration: none;
    padding: 12px 15px;
    margin-bottom: 8px;
    border-radius: 6px;
    transition: all 0.3s ease;
    font-weight: 500;
}

.sidebar a:hover {
    background-color: #334155;
    color: #fff;
    padding-left: 20px;
}

/* Right Content Area */
.content {
    margin-left: 260px; /* Matches sidebar width */
    padding: 0px 40px 40px 40px; /* Set top padding to 0px to align perfectly at the top */
    width: calc(100% - 260px);
    min-height: 100vh;
}

header {
    margin-top: 0; /* Ensures the header touches the very top edge */
    margin-bottom: 40px;
    background: linear-gradient(135deg, #38bdf8, #0284c7);
    color: white;
    padding: 30px;
    border-radius: 0 0 12px 12px; /* Keeps the rounded corners on the bottom only */
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}

header h1 {
    font-size: 2.2rem;
    margin-bottom: 5px;
}

/* Class Week Sections */
.week-section {
    background: #ffffff;
    padding: 30px;
    border-radius: 12px;
    margin-bottom: 30px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.02), 0 1px 3px rgba(0,0,0,0.05);
    border-left: 5px solid #0284c7;
}

.week-section h3 {
    font-size: 1.5rem;
    color: #0f172a;
    margin-bottom: 15px;
}

/* Link Cards */
.link-list {
    list-style: none;
}

.link-item {
    margin-bottom: 12px;
}

.link-item a {
    display: inline-block;
    color: #1d4ed8;
    text-decoration: none;
    font-size: 1.1rem;
    font-weight: 500;
    transition: color 0.2s;
}

.link-item a:hover {
    color: #1e40af;
    text-decoration: underline;
}

.link-description {
    font-size: 0.95rem;
    color: #64748b;
    margin-top: 2px;
}

/* Responsive design for mobile phone screens */
@media (max-width: 768px) {
    body {
        flex-direction: row; /* Keeps sidebar and content side-by-side */
    }
    
    .sidebar {
        width: 90px; /* Narrows the sidebar to save screen space */
        padding: 10px 5px;
        position: fixed;
        height: 100vh;
        top: 0;
        left: 0;
    }
    
    .sidebar h2 {
        font-size: 0.9rem; /* Shrinks the header title */
        margin-bottom: 15px;
        padding-bottom: 5px;
    }
    
    .sidebar a {
        font-size: 0.8rem; /* Small text for clean fit */
        padding: 10px 5px;
        text-align: center;
        margin-bottom: 5px;
        word-wrap: break-word; /* Prevents long words from cutting off */
    }
    
    .sidebar a:hover {
        padding-left: 5px; /* Disables wide slide effect on mobile touch screens */
    }
    
    .content {
        margin-left: 90px; /* Matches narrow mobile sidebar */
        width: calc(100% - 90px);
        padding: 0px 15px 15px 15px; /* Top padding 0px for mobile alignment */
    }

    header {
        padding: 15px;
        margin-top: 0;
        margin-bottom: 20px;
    }

    header h1 {
        font-size: 1.5rem;
    }

    .week-section {
        padding: 15px;
        margin-bottom: 20px;
    }
}