/* SufLearn - Main Stylesheet */
/* Clean, minimal, white background design */

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: #ffffff;
    color: #333333;
    line-height: 1.6;
}

a {
    text-decoration: none;
    color: inherit;
}

/* Container */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    padding: 60px 0;
    text-align: center;
    border-bottom: 1px solid #eeeeee;
}

.header-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

.logo-placeholder {
    width: 100px;
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 10px;
}

.logo-placeholder img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.site-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: #1a1a1a;
}

.site-description {
    font-size: 1.1rem;
    color: #666666;
    max-width: 500px;
    line-height: 1.7;
}

/* Section */
.section {
    padding: 60px 0;
    border-bottom: 1px solid #eeeeee;
}

.section:last-of-type {
    border-bottom: none;
}

.section-title {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 30px;
    color: #1a1a1a;
    text-align: center;
}

.section-subtitle {
    font-size: 1rem;
    color: #666666;
    text-align: center;
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* Method Section */
.method-item {
    margin-bottom: 40px;
    padding: 30px;
    background-color: #fafafa;
    border: 1px solid #eeeeee;
}

.method-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 15px;
    color: #1a1a1a;
}

.method-points {
    list-style: disc;
    padding-left: 20px;
}

.method-points li {
    margin-bottom: 8px;
    color: #555555;
}

/* Cards Grid */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.card {
    padding: 30px;
    background-color: #ffffff;
    border: 1px solid #dddddd;
    text-align: center;
    cursor: pointer;
}

.card:hover {
    border-color: #333333;
}

.card-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 10px;
    color: #1a1a1a;
}

.card-status {
    font-size: 0.85rem;
    padding: 5px 12px;
    display: inline-block;
}

.card-status.active {
    background-color: #e8f5e9;
    color: #2e7d32;
}

.card-status.coming-soon {
    background-color: #f5f5f5;
    color: #999999;
}

.card.disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.card.disabled:hover {
    border-color: #dddddd;
}

/* Material Buttons */
.material-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
    max-width: 600px;
    margin: 0 auto;
}

.material-btn {
    display: block;
    padding: 20px 30px;
    background-color: #ffffff;
    border: 1px solid #dddddd;
    font-size: 1.1rem;
    font-weight: 500;
    color: #333333;
    text-align: left;
    cursor: pointer;
}

.material-btn:hover {
    border-color: #333333;
    background-color: #fafafa;
}

/* Material Detail Page */
.page-header {
    padding: 40px 0;
    border-bottom: 1px solid #eeeeee;
}

.back-link {
    display: inline-block;
    margin-bottom: 20px;
    color: #666666;
    font-size: 0.9rem;
}

.back-link:hover {
    color: #333333;
}

.page-title {
    font-size: 2rem;
    font-weight: 700;
    color: #1a1a1a;
}

.video-container {
    width: 100%;
    max-width: 800px;
    margin: 40px auto;
    aspect-ratio: 16 / 9;
    background-color: #f5f5f5;
}

.video-container iframe {
    width: 100%;
    height: 100%;
    border: none;
}

.content-text {
    max-width: 800px;
    margin: 0 auto;
    padding: 40px 0;
    font-size: 1.05rem;
    line-height: 1.8;
    color: #444444;
    white-space: pre-line;
}

.navigation-buttons {
    display: flex;
    justify-content: space-between;
    max-width: 800px;
    margin: 0 auto;
    padding: 40px 0;
    border-top: 1px solid #eeeeee;
}

.nav-btn {
    padding: 12px 24px;
    background-color: #ffffff;
    border: 1px solid #dddddd;
    font-size: 0.95rem;
    color: #333333;
    cursor: pointer;
}

.nav-btn:hover {
    border-color: #333333;
    background-color: #fafafa;
}

.nav-btn.disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.nav-btn.disabled:hover {
    border-color: #dddddd;
    background-color: #ffffff;
}

/* Footer */
.footer {
    padding: 40px 0;
    text-align: center;
    background-color: #fafafa;
    border-top: 1px solid #eeeeee;
}

.footer-text {
    font-size: 0.9rem;
    color: #888888;
}

/* Page Container */
.page-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.page-content {
    flex: 1;
}

/* Breadcrumb */
.breadcrumb {
    padding: 20px 0;
    font-size: 0.9rem;
    color: #666666;
}

.breadcrumb a {
    color: #666666;
}

.breadcrumb a:hover {
    color: #333333;
}

.breadcrumb span {
    margin: 0 8px;
}

/* Loading State */
.loading {
    text-align: center;
    padding: 60px;
    color: #999999;
}

/* Responsive */
/* Logo Optimization */
.logo-placeholder {
    width: 120px;
    height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 15px;
    overflow: hidden;
    /* Ensure image doesn't overflow */
    border-radius: 50%;
    /* Optional: nice circular touch if logo allows, or remove */
    background-color: #f9f9f9;
    /* Light bg for transparent logos */
}

.logo-placeholder img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    /* Sharp and strictly fitted */
    transition: transform 0.3s ease;
}

.logo-placeholder:hover img {
    transform: scale(1.05);
    /* Micro-interaction */
}

/* Sponsor Section */
.sponsor-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    /* Responsive columns */
    gap: 30px;
    margin-top: 30px;
}

.sponsor-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.sponsor-img-container {
    width: 100%;
    aspect-ratio: 16 / 9;
    /* Consistent 1920x1080 ratio */
    background-color: #eeeeee;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.sponsor-img-container:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
}

.sponsor-img-container img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.sponsor-label {
    font-size: 0.75rem;
    color: #999999;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Enhanced Footer */
.footer {
    padding: 60px 0 40px;
    /* More breathing room */
    text-align: center;
    background-color: #f8f9fa;
    border-top: 1px solid #eeeeee;
}

.footer-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: #1a1a1a;
    margin-bottom: 10px;
}

.footer-quote {
    font-size: 1rem;
    color: #555555;
    font-style: italic;
    margin-bottom: 20px;
}

.footer-credit {
    font-size: 0.9rem;
    color: #888888;
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid #e0e0e0;
    max-width: 400px;
    margin-left: auto;
    margin-right: auto;
}

/* Responsive Adjustments */
@media (max-width: 768px) {
    .header {
        padding: 40px 0;
    }

    .header-content {
        gap: 15px;
    }

    .logo-placeholder {
        width: 100px;
        /* Smaller on mobile */
        height: 100px;
    }

    .site-title {
        font-size: 2rem;
    }

    .site-description {
        font-size: 1rem;
        padding: 0 10px;
        /* Prevent text touching edges */
    }

    .section {
        padding: 40px 0;
    }

    .section-title {
        font-size: 1.6rem;
    }

    .cards-grid {
        grid-template-columns: 1fr;
        /* Stack cards */
        padding: 0 10px;
        /* Edge spacing */
    }

    .sponsor-grid {
        grid-template-columns: 1fr;
        /* Stack sponsors */
        gap: 20px;
    }

    .page-title {
        font-size: 1.6rem;
        text-align: center;
        /* Ensure title centered on mobile */
    }

    .navigation-buttons {
        flex-direction: column;
        gap: 12px;
    }

    .nav-btn {
        width: 100%;
        text-align: center;
        padding: 15px;
        /* Larger touch target */
    }
}