/* ================================================
   EngiSuite Learning Platform - Modern Styles
   Based on Universal Theme System
   ================================================ */

/* Remove conflicting Tailwind import - use universal theme instead */

/* ================================================
   Typography
   ================================================ */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 0.5rem;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
p { margin-bottom: 1rem; }

/* ================================================
   Custom Scrollbar - Consistent across all themes
   ================================================ */
.sidebar-scroll::-webkit-scrollbar {
    width: 6px;
}
.sidebar-scroll::-webkit-scrollbar-track {
    background: var(--bg-muted);
}
.sidebar-scroll::-webkit-scrollbar-thumb {
    background: var(--border-default);
    border-radius: 3px;
}
.sidebar-scroll::-webkit-scrollbar-thumb:hover {
    background: var(--border-strong);
}

/* ================================================
   Tree Navigation Styles - Clean and professional
   ================================================ */
.tree-item {
    transition: all 0.2s ease;
}
.tree-item:hover {
    background-color: var(--bg-surface-hover);
}
.tree-children {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}
.tree-children.expanded {
    max-height: 2000px;
}
.tree-toggle {
    transition: transform 0.2s ease;
}
.tree-toggle.expanded {
    transform: rotate(90deg);
}

/* ================================================
   Tab Styles - Professional and consistent
   ================================================ */
.tab-btn {
    transition: all 0.2s ease;
    border-bottom: 2px solid transparent;
}
.tab-btn.active {
    border-bottom-color: var(--primary);
    color: var(--primary);
}

/* ================================================
   Active Lesson Highlight - Clear and accessible
   ================================================ */
.lesson-active {
    background-color: var(--primary-light);
    border-left: 3px solid var(--primary);
}

/* ================================================
   Welcome Screen - Modern, clean design
   ================================================ */
#welcome-screen {
    background: linear-gradient(135deg, var(--bg-surface) 0%, var(--bg-muted) 100%);
}

.welcome-icon {
    font-size: 6rem;
    color: var(--primary);
    margin-bottom: 1rem;
}

.welcome-card {
    background: var(--bg-surface);
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-lg);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.welcome-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.welcome-card i {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    display: block;
}

/* ================================================
   Lesson Header - Clean and organized
   ================================================ */
#lesson-header {
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border-default);
}

#lesson-header h1 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.lesson-meta {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* ================================================
   Lesson Content - Readable and professional
   ================================================ */
#lesson-content {
    background: var(--bg-surface);
}

.tab-panel {
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ================================================
   Prose Content - Enhanced readability
   ================================================ */
.prose {
    color: var(--text-primary);
    max-width: 100%;
}

.prose h1,
.prose h2,
.prose h3,
.prose h4,
.prose h5,
.prose h6 {
    color: var(--text-primary);
    margin-top: 2rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.prose p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 1.25rem;
}

.prose a {
    color: var(--primary);
    text-decoration: none;
    transition: color 0.2s ease;
}

.prose a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* ================================================
   Simulations & Quiz Containers - Modern design
   ================================================ */
.simulation-card,
.quiz-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-default);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow-sm);
    transition: all 0.2s ease;
}

.simulation-card:hover,
.quiz-card:hover {
    box-shadow: var(--shadow-md);
}

/* ================================================
   Empty State - Clean and informative
   ================================================ */
.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    color: var(--text-muted);
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

/* ================================================
   Responsive Design - Mobile-first approach
   ================================================ */
@media (max-width: 768px) {
    /* Sidebar adjustments */
    #sidebar {
        position: fixed;
        left: -100%;
        top: 0;
        height: 100vh;
        z-index: 1000;
        transition: left 0.3s ease;
    }
    
    #sidebar.open {
        left: 0;
    }
    
    /* Welcome screen adjustments */
    .welcome-grid {
        grid-template-columns: 1fr !important;
        gap: 1rem !important;
    }
    
    /* Lesson header adjustments */
    #lesson-header {
        padding: 1rem;
    }
    
    #lesson-header h1 {
        font-size: 1.5rem;
    }
    
    /* Tab adjustments */
    .tab-btn {
        font-size: 0.875rem;
        padding: 0.75rem 1rem;
    }
}