/* 🎯 Topics.css - Level Overview Pages Styling */

:root {
    --level-1-color: #10b981;
    --level-2-color: #3b82f6;
    --level-3-color: #8b5cf6;
    --level-4-color: #f59e0b;
}

/* Topics Grid Layout */
.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Topic Card */
.topic-card {
    background: rgba(30, 41, 59, 0.5);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    padding: 30px;
    position: relative;
    overflow: hidden;
    transition: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
    cursor: pointer;
    text-decoration: none;
    display: block;
}

.topic-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--card-accent), transparent);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.topic-card:hover::before {
    opacity: 1;
}

.topic-card:hover {
    transform: translateY(-8px);
    border-color: rgba(255, 255, 255, 0.2);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

/* Topic Number Badge */
.topic-number {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--card-accent), var(--card-accent-dark));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    font-weight: 700;
    color: white;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

/* Topic Icon */
.topic-icon {
    font-size: 3rem;
    margin-bottom: 15px;
    display: block;
    filter: drop-shadow(0 2px 8px rgba(0, 0, 0, 0.3));
}

/* Topic Title */
.topic-card h3 {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: 12px;
    line-height: 1.3;
    font-weight: 600;
}

/* Topic Description */
.topic-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
    margin-bottom: 20px;
    opacity: 0.9;
}

/* Topic Meta Info */
.topic-meta {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    opacity: 0.8;
}

.meta-item span {
    opacity: 0.6;
}

/* Difficulty Badge */
.difficulty-badge {
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.difficulty-beginner {
    background: rgba(16, 185, 129, 0.15);
    color: #10b981;
    border: 1px solid rgba(16, 185, 129, 0.3);
}

.difficulty-intermediate {
    background: rgba(59, 130, 246, 0.15);
    color: #3b82f6;
    border: 1px solid rgba(59, 130, 246, 0.3);
}

.difficulty-advanced {
    background: rgba(139, 92, 246, 0.15);
    color: #8b5cf6;
    border: 1px solid rgba(139, 92, 246, 0.3);
}

.difficulty-expert {
    background: rgba(245, 158, 11, 0.15);
    color: #f59e0b;
    border: 1px solid rgba(245, 158, 11, 0.3);
}

/* Level-specific accent colors */
.level-1 .topic-card {
    --card-accent: var(--level-1-color);
    --card-accent-dark: #059669;
}

.level-2 .topic-card {
    --card-accent: var(--level-2-color);
    --card-accent-dark: #2563eb;
}

.level-3 .topic-card {
    --card-accent: var(--level-3-color);
    --card-accent-dark: #7c3aed;
}

.level-4 .topic-card {
    --card-accent: var(--level-4-color);
    --card-accent-dark: #d97706;
}

/* Level Header */
.level-header {
    text-align: center;
    margin-bottom: 60px;
}

.level-title {
    font-family: var(--font-heading);
    font-size: 3rem;
    margin-bottom: 15px;
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.level-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto;
    line-height: 1.6;
}

/* Progress Indicator */
.progress-container {
    margin-top: 30px;
    padding: 20px;
    background: rgba(30, 41, 59, 0.3);
    border-radius: 16px;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.progress-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 10px;
    display: flex;
    justify-content: space-between;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 10px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--card-accent), var(--card-accent-dark));
    border-radius: 10px;
    transition: width 0.6s ease;
}

/* Responsive Design */
@media (max-width: 768px) {
    .topics-grid {
        grid-template-columns: 1fr;
        gap: 20px;
        padding: 15px;
    }

    .level-title {
        font-size: 2.2rem;
    }

    .level-subtitle {
        font-size: 1rem;
    }

    .topic-card {
        padding: 25px;
    }

    .topic-number {
        width: 40px;
        height: 40px;
        font-size: 1rem;
    }
}

/* Animation Utilities */
@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-in {
    animation: slideInUp 0.6s ease-out forwards;
}

/* Stagger animation delays */
.topic-card:nth-child(1) {
    animation-delay: 0.1s;
}

.topic-card:nth-child(2) {
    animation-delay: 0.2s;
}

.topic-card:nth-child(3) {
    animation-delay: 0.3s;
}

.topic-card:nth-child(4) {
    animation-delay: 0.4s;
}

.topic-card:nth-child(5) {
    animation-delay: 0.5s;
}

.topic-card:nth-child(6) {
    animation-delay: 0.6s;
}