/* Enhanced DSA Pattern Explorer Styles */
:root {
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --secondary-color: #0ea5e9;
    --accent-color: #10b981;
    --success-color: #059669;
    --warning-color: #d97706;
    --error-color: #dc2626;
    --text-main: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #9ca3af;
    --bg-main: #f8fafc;
    --bg-card: #ffffff;
    --bg-code: #1e293b;
    --bg-gray-50: #f9fafb;
    --bg-gray-100: #f3f4f6;
    --border-color: #e2e8f0;
    --border-hover: #cbd5e1;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --transition: all 0.2s ease-in-out;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Utility Classes */
.transition-all { transition: var(--transition); }
.shadow-sm { box-shadow: var(--shadow-sm); }
.shadow-md { box-shadow: var(--shadow-md); }
.shadow-lg { box-shadow: var(--shadow-lg); }

/* Header Styles */
header {
    background-color: var(--bg-card);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

/* Code Syntax Highlighting */
.code-block {
    background-color: var(--bg-code);
    color: #f8fafc;
    border-radius: 0.5rem;
    overflow-x: auto;
    font-family: 'Fira Code', 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
    font-size: 0.875rem;
    line-height: 1.5;
}

.code-block pre {
    padding: 1.5rem;
    margin: 0;
    white-space: pre;
    word-wrap: normal;
}

/* Syntax highlighting colors */
.keyword { color: #8b5cf6; }
.string { color: #10b981; }
.number { color: #f59e0b; }
.comment { color: #6b7280; font-style: italic; }
.function { color: #3b82f6; }
.variable { color: #06b6d4; }

/* Interactive Elements */
.interactive-demo {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 1rem;
    padding: 2rem;
    color: white;
    margin: 1.5rem 0;
}

.demo-controls {
    display: flex;
    gap: 0.75rem;
    margin-top: 1rem;
    flex-wrap: wrap;
}

.demo-btn {
    padding: 0.5rem 1rem;
    background-color: rgba(255, 255, 255, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: white;
    border-radius: 0.375rem;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
    font-size: 0.875rem;
}

.demo-btn:hover {
    background-color: rgba(255, 255, 255, 0.3);
    transform: translateY(-1px);
}

/* Visualization Containers */
.visualization-container {
    background-color: var(--bg-gray-50);
    border: 2px dashed var(--border-color);
    border-radius: 0.75rem;
    padding: 2rem;
    min-height: 300px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.visualization-container:hover {
    border-color: var(--primary-color);
    background-color: rgba(59, 130, 246, 0.02);
}

/* Algorithm Step Visualization */
.algo-step {
    display: flex;
    align-items: center;
    padding: 1rem;
    border-radius: 0.5rem;
    margin: 0.5rem 0;
    transition: var(--transition);
    border-left: 4px solid transparent;
}

.algo-step.active {
    background-color: rgba(59, 130, 246, 0.1);
    border-left-color: var(--primary-color);
}

.algo-step.completed {
    background-color: rgba(16, 185, 129, 0.1);
    border-left-color: var(--success-color);
}

/* Array Visualization */
.array-container {
    display: flex;
    gap: 0.25rem;
    align-items: center;
    justify-content: center;
    margin: 1rem 0;
    flex-wrap: wrap;
}

.array-element {
    width: 3rem;
    height: 3rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--bg-gray-100);
    border: 2px solid var(--border-color);
    border-radius: 0.375rem;
    font-weight: 600;
    font-size: 0.875rem;
    transition: var(--transition);
    position: relative;
}

.array-element.highlight {
    background-color: #fef3c7;
    border-color: #f59e0b;
    color: #92400e;
    transform: scale(1.1);
}

.array-element.success {
    background-color: #d1fae5;
    border-color: var(--success-color);
    color: #065f46;
}

.array-element.error {
    background-color: #fee2e2;
    border-color: var(--error-color);
    color: #991b1b;
}

.array-element::after {
    content: attr(data-index);
    position: absolute;
    top: -1.5rem;
    font-size: 0.625rem;
    color: var(--text-muted);
    font-weight: normal;
}

/* Tree Visualization */
.tree-container {
    position: relative;
    width: 100%;
    min-height: 300px;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 2rem;
    overflow: auto;
}

.tree-node {
    width: 2.5rem;
    height: 2.5rem;
    border-radius: 50%;
    background-color: var(--bg-card);
    border: 2px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.75rem;
    position: absolute;
    transition: var(--transition);
    cursor: pointer;
}

.tree-node:hover {
    border-color: var(--primary-color);
    background-color: rgba(59, 130, 246, 0.1);
    transform: scale(1.1);
}

.tree-node.visited {
    background-color: rgba(16, 185, 129, 0.2);
    border-color: var(--success-color);
}

.tree-edge {
    position: absolute;
    height: 2px;
    background-color: var(--border-color);
    transform-origin: 0 0;
    transition: var(--transition);
}

.tree-edge.active {
    background-color: var(--primary-color);
    height: 3px;
}

/* Graph Visualization */
.graph-container {
    position: relative;
    width: 100%;
    height: 400px;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    background-color: var(--bg-card);
    overflow: hidden;
}

.graph-node {
    position: absolute;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--primary-color);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.875rem;
    cursor: pointer;
    transition: var(--transition);
    z-index: 2;
}

.graph-node:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-md);
}

.graph-edge {
    position: absolute;
    height: 2px;
    background-color: var(--text-muted);
    z-index: 1;
    transition: var(--transition);
}

.graph-edge.highlighted {
    background-color: var(--warning-color);
    height: 3px;
}

/* Complexity Analysis */
.complexity-analysis {
    background: linear-gradient(135deg, #f3f4f6 0%, #e5e7eb 100%);
    border-radius: 0.75rem;
    padding: 1.5rem;
    margin: 1.5rem 0;
    border: 1px solid var(--border-color);
}

.complexity-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid rgba(156, 163, 175, 0.3);
}

.complexity-item:last-child {
    border-bottom: none;
}

.complexity-label {
    font-weight: 600;
    color: var(--text-main);
}

.complexity-value {
    font-family: 'Fira Code', monospace;
    background-color: var(--bg-card);
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    border: 1px solid var(--border-color);
    font-size: 0.875rem;
}

/* Problem Cards */
.problem-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 1rem;
    transition: var(--transition);
    cursor: pointer;
}

.problem-card:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.problem-title {
    font-weight: 600;
    color: var(--text-main);
    margin-bottom: 0.5rem;
}

.problem-difficulty {
    display: inline-block;
    padding: 0.125rem 0.5rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 500;
}

.difficulty-easy {
    background-color: rgba(16, 185, 129, 0.1);
    color: var(--success-color);
}

.difficulty-medium {
    background-color: rgba(245, 158, 11, 0.1);
    color: var(--warning-color);
}

.difficulty-hard {
    background-color: rgba(220, 38, 38, 0.1);
    color: var(--error-color);
}

/* Progress Indicators */
.progress-bar {
    width: 100%;
    height: 0.5rem;
    background-color: var(--bg-gray-100);
    border-radius: 9999px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 9999px;
    transition: width 0.5s ease-in-out;
}

/* Tooltips */
.tooltip {
    position: relative;
    display: inline-block;
}

.tooltip-content {
    visibility: hidden;
    position: absolute;
    z-index: 999;
    bottom: 125%;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--bg-code);
    color: white;
    padding: 0.5rem;
    border-radius: 0.375rem;
    font-size: 0.75rem;
    white-space: nowrap;
    opacity: 0;
    transition: opacity 0.3s;
}

.tooltip-content::after {
    content: "";
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 5px solid transparent;
    border-top-color: var(--bg-code);
}

.tooltip:hover .tooltip-content {
    visibility: visible;
    opacity: 1;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideIn {
    from { transform: translateY(20px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.animate-fade-in { animation: fadeIn 0.3s ease-in-out; }
.animate-slide-in { animation: slideIn 0.5s ease-out; }
.animate-pulse { animation: pulse 2s infinite; }

/* Loading States */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid var(--bg-gray-100);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Responsive Design */
@media (max-width: 768px) {
    .array-container {
        justify-content: flex-start;
        overflow-x: auto;
        padding-bottom: 0.5rem;
    }
    
    .array-element {
        flex-shrink: 0;
    }
    
    .tree-container {
        padding: 1rem;
    }
    
    .complexity-analysis {
        padding: 1rem;
    }
    
    .demo-controls {
        justify-content: center;
    }
}

/* Print Styles */
@media print {
    header { display: none; }
    #sidebar { display: none; }
    .visualization-container { border: 1px solid #ccc; }
    .interactive-demo { background: #f5f5f5 !important; color: black !important; }
}