/* 
   Course Template Styles
   Used for all course pages in /teaching/templates/isibc/
   Author: Indrajit Ghosh
   Created: Jan 23, 2026
*/

:root {
    --color-black: #000000;
    --color-white: #ffffff;
    --color-dark: #353535;
    --color-dark-variant: #555555;
    
    --primary-color: var(--color-dark);
    --accent-color: var(--color-dark-variant);
    --secondary-color: var(--color-dark-variant);
    --light-bg: #f8f9fa;
}

.page-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, #34495e 100%);
    color: white;
    padding: 3rem 2rem;
    margin-bottom: 3rem;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin: 0 0 1rem 0;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--color-white);
}

.course-meta {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.meta-item {
    background: rgba(255, 255, 255, 0.1);
    padding: 1rem;
    border-radius: 8px;
    border-left: 4px solid var(--accent-color);
}

.meta-item-label {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    opacity: 0.9;
    margin-bottom: 0.3rem;
}

.meta-item-value {
    font-size: 1rem;
    font-weight: 600;
}

.section-heading {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-top: 2.5rem;
    margin-bottom: 1.5rem;
    position: relative;
    padding-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.section-heading::before {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 50px;
    height: 3px;
    background: var(--accent-color);
    border-radius: 2px;
}

.section-heading i {
    font-size: 1.5rem;
    color: var(--secondary-color);
}

.textbooks-list {
    background: white;
    border-radius: 10px;
    padding: 2rem;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    margin-bottom: 2rem;
}

.textbooks-list ol {
    margin-bottom: 0;
}

.textbooks-list li {
    margin-bottom: 1rem;
    color: #555;
    line-height: 1.6;
}

.textbooks-list i {
    font-style: italic;
    color: #333;
}

.textbooks-list a {
    color: var(--secondary-color);
    text-decoration: none;
}

.textbooks-list a:hover {
    text-decoration: underline;
}

.info-box {
    background: #f0f7ff;
    border-left: 5px solid var(--accent-color);
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 2rem;
}

.info-box p {
    margin: 0.5rem 0;
    color: #2c3e50;
}

.info-box p:first-child {
    margin-top: 0;
}

.info-box p:last-child {
    margin-bottom: 0;
}

.info-box strong {
    color: var(--secondary-color);
}

.assignment-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.assignment-card {
    background: white;
    border-radius: 10px;
    padding: 1.5rem;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    border-top: 4px solid var(--secondary-color);
    transition: all 0.3s ease;
}

.assignment-card:hover {
    box-shadow: 0 6px 20px rgba(0,0,0,0.1);
    transform: translateY(-3px);
}

.assignment-number {
    font-size: 0.9rem;
    color: var(--secondary-color);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.5rem;
}

.assignment-link {
    display: inline-block;
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all 0.3s ease;
}

.assignment-link:hover {
    color: var(--accent-color);
    text-decoration: underline;
}

.due-date {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 1rem;
    color: #777;
    font-size: 0.95rem;
}

.due-date i {
    color: var(--accent-color);
}

.container-course {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.last-updated {
    text-align: center;
    color: #888;
    font-size: 0.9rem;
    margin-top: 3rem;
}

.assignment {
    background: linear-gradient(135deg, #f8f9fa 0%, #e8ecf1 100%);
    padding: 2.5rem;
    margin: 2rem 0;
    border-radius: 12px;
    border-left: 6px solid var(--secondary-color);
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.1);
}

.assignment h2 {
    color: var(--primary-color);
    font-size: 1.8rem;
    font-weight: 700;
    margin-top: 0;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 3px solid var(--secondary-color);
}

.assignment .due-date {
    color: var(--accent-color);
    font-weight: 600;
    margin-bottom: 1.5rem;
    font-size: 1rem;
}

.problem {
    background: white;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.05);
    border-left: 4px solid var(--accent-color);
}

.problem b {
    color: var(--secondary-color);
    font-size: 1.1rem;
    display: block;
    margin-bottom: 0.8rem;
}

.problem p {
    color: #333;
    line-height: 1.7;
}

.back-to-top {
    display: inline-block;
    margin-top: 1.5rem;
    padding: 0.7rem 1.5rem;
    background: linear-gradient(135deg, var(--secondary-color) 0%, #2980b9 100%);
    color: white;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 600;
    transition: all 0.3s ease;
}

.back-to-top:hover {
    background: linear-gradient(135deg, #2980b9 0%, #1e5fa3 100%);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(52, 152, 219, 0.3);
}

.center-img {
    text-align: center;
    margin: 1.5rem 0;
}

.center-img img {
    max-width: 100%;
    width: 450px;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.center-img figcaption {
    margin-top: 0.8rem;
    font-size: 0.9rem;
    color: #666;
    font-style: italic;
}

/* Responsive Design */
@media (max-width: 768px) {
    .page-header {
        padding: 2rem 1.5rem;
        margin-bottom: 2rem;
    }

    .page-header h1 {
        font-size: 1.8rem;
    }

    .course-meta {
        grid-template-columns: repeat(2, 1fr);
        gap: 1rem;
    }

    .meta-item {
        padding: 0.8rem;
    }

    .assignment-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .section-heading {
        font-size: 1.3rem;
        margin-top: 2rem;
        margin-bottom: 1rem;
    }

    .textbooks-list {
        padding: 1.5rem;
    }

    .textbooks-list li {
        margin-bottom: 0.8rem;
    }
}

@media (max-width: 480px) {
    .page-header {
        padding: 1.5rem 1rem;
        margin-bottom: 1.5rem;
    }

    .page-header h1 {
        font-size: 1.4rem;
        margin-bottom: 0.8rem;
    }

    .course-meta {
        grid-template-columns: 1fr;
        gap: 0.8rem;
    }

    .meta-item {
        padding: 0.7rem;
        border-left-width: 3px;
    }

    .meta-item-label {
        font-size: 0.8rem;
    }

    .meta-item-value {
        font-size: 0.95rem;
    }

    .section-heading {
        font-size: 1.2rem;
        margin-top: 1.5rem;
        margin-bottom: 1rem;
        gap: 0.6rem;
    }

    .section-heading i {
        font-size: 1.2rem;
    }

    .textbooks-list {
        padding: 1.2rem;
    }

    .textbooks-list li {
        margin-bottom: 0.8rem;
        font-size: 0.95rem;
    }

    .assignment-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .assignment-card {
        padding: 1.2rem;
        border-top-width: 3px;
    }

    .assignment-link {
        font-size: 1rem;
    }

    .info-box {
        padding: 1.2rem;
        border-left-width: 4px;
    }

    .info-box p {
        font-size: 0.95rem;
    }

    .assignment {
        padding: 1.8rem;
    }

    .assignment h2 {
        font-size: 1.4rem;
        margin-bottom: 0.8rem;
    }

    .problem {
        padding: 1.2rem;
        margin-bottom: 1.2rem;
    }

    .problem b {
        font-size: 1rem;
    }
}