:root {
    --primary-color: #2c3e50;
    --secondary-color: #34495e;
    --accent-color: #3498db;
    --text-color: #2c3e50;
    --light-bg: #f8f9fa;
}

body {
    color: var(--text-color);
    line-height: 1.6;
}

/* Narrower container */
.container {
    max-width: 1000px;
}

.hero-section {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 5rem 0;
}

.course-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.course-subtitle {
    font-size: 2rem;
    opacity: 0.9;
    margin-bottom: 2rem;
}

.section-title {
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 2rem;
    border-bottom: 3px solid var(--accent-color);
    padding-bottom: 0.5rem;
}

.card {
    border: none;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    margin-bottom: 1.5rem;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.15);
}

/* Weekly structure styling */
.week-section {
    background: white;
    border: 1px solid #dee2e6;
    border-radius: 8px;
    margin-bottom: 1.5rem;
    overflow: hidden;
}

.week-header {
    background: linear-gradient(135deg, var(--accent-color), #2980b9);
    color: white;
    padding: 1rem 1.5rem;
    font-weight: 600;
    font-size: 1.1rem;
}

.week-content {
    padding: 1.5rem;
}

.week-topics {
    background: var(--light-bg);
    padding: 1rem;
    border-radius: 5px;
    margin-bottom: 1rem;
}

.assignment-item {
    background: #e8f5e8;
    border-left: 4px solid #27ae60;
    padding: 0.75rem;
    margin: 0.5rem 0;
    border-radius: 0 5px 5px 0;
}

.guest-item {
    background: #fdeaea;
    border-left: 4px solid #e74c3c;
    padding: 0.75rem;
    margin: 0.5rem 0;
    border-radius: 0 5px 5px 0;
}

.reading-item {
    background: #f0f8ff;
    border-left: 4px solid #3498db;
    padding: 0.75rem;
    margin: 0.5rem 0;
    border-radius: 0 5px 5px 0;
}

.navbar {
    background-color: white !important;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.navbar-brand {
    font-weight: 600;
    color: var(--primary-color) !important;
}

.nav-link {
    color: var(--text-color) !important;
    font-weight: 500;
}

.nav-link:hover {
    color: var(--accent-color) !important;
}

.course-info {
    background-color: var(--light-bg);
    border-radius: 10px;
    padding: 2rem;
    margin-bottom: 3rem;
}

.footer {
    background-color: var(--primary-color);
    color: white;
    padding: 3rem 0;
    margin-top: 5rem;
}

.badge-assignment {
    background-color: #27ae60;
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
}

.badge-guest {
    background-color: #e74c3c;
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
}

.badge-reading {
    background-color: #3498db;
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
}

/* Guest speaker specific styles */
.guest-speaker-card {
    border-left: 4px solid #e74c3c;
    position: relative;
}

.speaker-photo {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid #e74c3c;
    margin-bottom: 1rem;
}

.speaker-date {
    background: rgba(231, 76, 60, 0.9);
    color: white;
    padding: 0.3rem 0.7rem;
    border-radius: 0 0 0 15px;
    font-size: 0.75rem;
    font-weight: 500;
    position: absolute;
    top: 0;
    right: 0;
    margin: 0;
    box-shadow: 0 2px 6px rgba(231, 76, 60, 0.2);
}

.project-card {
    border-left: 4px solid #9b59b6;
}