/* CSS Variables for design tokens */
:root {
    --bg-main: #0b0f19;
    --bg-sidebar: #070a12;
    --bg-card: rgba(17, 24, 39, 0.7);
    --border-color: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(255, 255, 255, 0.15);
    
    --color-primary: #8b5cf6;
    --color-primary-glow: rgba(139, 92, 246, 0.25);
    --color-secondary: #06b6d4;
    --color-secondary-glow: rgba(6, 182, 212, 0.25);
    --color-accent: #ec4899;
    --color-accent-glow: rgba(236, 72, 153, 0.25);
    
    --color-success: #10b981;
    --color-error: #ef4444;
    --color-warning: #f59e0b;
    --color-info: #3b82f6;
    
    --text-primary: #f3f4f6;
    --text-muted: #9ca3af;
    --text-dark: #4b5563;
    
    --font-sans: 'Outfit', sans-serif;
    --font-mono: 'Fira Code', monospace;
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    
    --sidebar-width: 260px;
    --card-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    --glass-blur: blur(12px);
}

/* Global Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    scrollbar-width: thin;
    scrollbar-color: var(--color-primary-glow) transparent;
}

body {
    background-color: var(--bg-main);
    color: var(--text-primary);
    font-family: var(--font-sans);
    overflow-x: hidden;
    height: 100vh;
    width: 100vw;
}

/* Mobile Header Bar */
.mobile-header {
    display: none;
    height: 60px;
    background-color: var(--bg-sidebar);
    border-bottom: 1px solid var(--border-color);
    padding: 0 1.25rem;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 100;
}

.mobile-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.mobile-brand h2 {
    font-size: 1.2rem;
    font-weight: 700;
    background: linear-gradient(to right, #ffffff, #d1d5db);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.mobile-menu-btn {
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 1.4rem;
    cursor: pointer;
}

/* App Container Layout */
.app-container {
    display: flex;
    height: 100vh;
    width: 100vw;
    position: relative;
}

/* Sidebar Styling */
.sidebar {
    width: var(--sidebar-width);
    background-color: var(--bg-sidebar);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    padding: 2rem 1.5rem;
    flex-shrink: 0;
    z-index: 90;
    transition: transform 0.3s ease;
}

.sidebar-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 3rem;
}

.brand-icon {
    font-size: 1.75rem;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    filter: drop-shadow(0 0 8px var(--color-primary-glow));
}

.sidebar-brand h2 {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    background: linear-gradient(to right, #ffffff, #d1d5db);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.sidebar-nav {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    flex-grow: 1;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.85rem 1rem;
    background: none;
    border: none;
    border-radius: 12px;
    color: var(--text-muted);
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    text-align: left;
    transition: var(--transition-fast);
}

.nav-item i {
    font-size: 1.15rem;
    width: 1.25rem;
    text-align: center;
    transition: var(--transition-fast);
}

.nav-item:hover {
    color: #ffffff;
    background-color: rgba(255, 255, 255, 0.03);
}

.nav-item.active {
    color: #ffffff;
    background: linear-gradient(135deg, rgba(139, 92, 246, 0.15), rgba(6, 182, 212, 0.05));
    border: 1px solid rgba(139, 92, 246, 0.3);
    box-shadow: 0 0 15px rgba(139, 92, 246, 0.1);
}

.nav-item.active i {
    color: var(--color-primary);
    filter: drop-shadow(0 0 5px var(--color-primary-glow));
}

.sidebar-footer {
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
    font-size: 0.75rem;
    color: var(--text-dark);
    text-align: center;
}

/* Main Content Area */
.main-content {
    flex-grow: 1;
    height: 100vh;
    overflow-y: auto;
    padding: 2.5rem;
    position: relative;
}

.tab-content {
    display: none;
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.4s ease, transform 0.4s ease;
    height: 100%;
}

.tab-content.active {
    display: block;
    opacity: 1;
    transform: translateY(0);
}

.section-header {
    margin-bottom: 2.5rem;
}

.section-header h2 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.section-header p {
    color: var(--text-muted);
    font-size: 1.05rem;
}

.dashboard-layout {
    display: grid;
    grid-template-columns: 1fr 340px;
    gap: 2rem;
    align-items: start;
    margin-bottom: 2rem;
}

.visualizer-card {
    background-color: var(--bg-card);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--border-color);
    border-radius: 18px;
    padding: 1.5rem;
    box-shadow: var(--card-shadow);
}

.sidebar-panel {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.info-card {
    background-color: var(--bg-card);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--border-color);
    border-radius: 18px;
    padding: 1.5rem;
    box-shadow: var(--card-shadow);
}

.info-card h3 {
    font-size: 1.15rem;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border-color);
    color: #ffffff;
}

.flex-grow-card {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    max-height: 480px;
}

.hero-section {
    position: relative;
    padding: 4rem 2.5rem;
    border-radius: 24px;
    background: linear-gradient(135deg, #131224 0%, #070b13 100%);
    border: 1px solid var(--border-color);
    overflow: hidden;
    margin-bottom: 2.5rem;
    box-shadow: var(--card-shadow);
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 80% 20%, rgba(139, 92, 246, 0.12) 0%, transparent 60%);
    pointer-events: none;
}

.hero-text {
    position: relative;
    z-index: 2;
    max-width: 600px;
}

.badge {
    display: inline-block;
    padding: 0.35rem 0.85rem;
    background-color: rgba(139, 92, 246, 0.12);
    border: 1px solid rgba(139, 92, 246, 0.3);
    color: var(--color-primary);
    border-radius: 50px;
    font-size: 0.8rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin-bottom: 1.5rem;
}

.hero-text h1 {
    font-size: 2.75rem;
    font-weight: 700;
    line-height: 1.15;
    margin-bottom: 1rem;
    letter-spacing: -0.03em;
    background: linear-gradient(to right, #ffffff 30%, #a78bfa 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-desc {
    font-size: 1.1rem;
    color: var(--text-muted);
    line-height: 1.6;
    margin-bottom: 2rem;
}

.typewriter-container {
    font-family: var(--font-mono);
    font-size: 1.15rem;
    color: var(--color-secondary);
    background-color: rgba(6, 182, 212, 0.05);
    border: 1px solid rgba(6, 182, 212, 0.2);
    padding: 0.75rem 1.25rem;
    border-radius: 8px;
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    box-shadow: 0 4px 15px rgba(6, 182, 212, 0.08);
}

.typewriter-cursor {
    animation: blink 0.8s infinite;
    font-weight: bold;
    color: var(--color-secondary);
}

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

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.feature-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 18px;
    padding: 1.75rem;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: rgba(139, 92, 246, 0.3);
    box-shadow: 0 10px 25px rgba(139, 92, 246, 0.08);
}

.card-icon {
    width: 3.25rem;
    height: 3.25rem;
    border-radius: 14px;
    background: linear-gradient(135deg, rgba(139, 92, 246, 0.1), rgba(6, 182, 212, 0.1));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.35rem;
    color: var(--color-primary);
    margin-bottom: 1.25rem;
    border: 1px solid rgba(139, 92, 246, 0.15);
}

.feature-card h3 {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.feature-card p {
    font-size: 0.95rem;
    color: var(--text-muted);
    line-height: 1.5;
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.learn-more {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--color-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: var(--transition-fast);
}

.feature-card:hover .learn-more {
    color: var(--color-secondary);
    gap: 0.75rem;
}

.control-bar {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 1.25rem;
    padding-bottom: 1.25rem;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 1.5rem;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.control-group label {
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
}

.custom-select {
    background-color: #121824;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0.5rem 1rem;
    color: #ffffff;
    font-family: var(--font-sans);
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition-fast);
}

.custom-select:hover, .custom-select:focus {
    border-color: var(--color-primary);
    outline: none;
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    background: #1f2937;
    height: 6px;
    border-radius: 3px;
    outline: none;
    width: 140px;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--color-primary);
    cursor: pointer;
    box-shadow: 0 0 8px var(--color-primary-glow);
    transition: var(--transition-fast);
}

input[type="range"]::-webkit-slider-thumb:hover {
    background: var(--color-secondary);
    transform: scale(1.1);
}

.btn-group {
    display: flex;
    gap: 0.75rem;
    margin-left: auto;
}

.btn {
    font-family: var(--font-sans);
    font-size: 0.9rem;
    font-weight: 600;
    padding: 0.55rem 1.25rem;
    border-radius: 8px;
    cursor: pointer;
    border: 1px solid transparent;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: var(--transition-fast);
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), #7c3aed);
    color: #ffffff;
    box-shadow: 0 4px 14px rgba(139, 92, 246, 0.3);
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-1px);
    box-shadow: 0 6px 20px rgba(139, 92, 246, 0.45);
}

.btn-secondary {
    background-color: #1f2937;
    border-color: var(--border-color);
    color: var(--text-primary);
}

.btn-secondary:hover:not(:disabled) {
    background-color: #374151;
    border-color: var(--border-hover);
}

.btn-accent {
    background-color: rgba(6, 182, 212, 0.1);
    border-color: rgba(6, 182, 212, 0.3);
    color: var(--color-secondary);
}

.btn-accent:hover:not(:disabled) {
    background-color: rgba(6, 182, 212, 0.2);
    border-color: var(--color-secondary);
}

.btn-copy {
    background-color: rgba(139, 92, 246, 0.1);
    border: 1px solid rgba(139, 92, 246, 0.3);
    color: var(--color-primary);
    padding: 0.3rem 0.75rem;
    font-size: 0.8rem;
    border-radius: 6px;
    cursor: pointer;
    transition: var(--transition-fast);
}

.btn-copy:hover {
    background-color: rgba(139, 92, 246, 0.2);
    border-color: var(--color-primary);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: none !important;
}

.input-panel {
    background-color: rgba(255, 255, 255, 0.02);
    border: 1px dashed var(--border-color);
    padding: 1rem;
    border-radius: 12px;
    margin-bottom: 1.5rem;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.input-group label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.input-with-btn {
    display: flex;
    gap: 0.75rem;
}

.custom-text-input {
    flex-grow: 1;
    background-color: #121824;
    border: 1px solid var(--border-color);
    color: #ffffff;
    padding: 0.55rem 1rem;
    border-radius: 8px;
    font-family: var(--font-mono);
    font-size: 0.9rem;
    outline: none;
    transition: var(--transition-fast);
}

.custom-text-input:focus {
    border-color: var(--color-secondary);
}

.error-msg {
    color: var(--color-error);
    font-size: 0.8rem;
    margin-top: 0.2rem;
}

.visualizer-container {
    background-color: #080b11;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    height: 340px;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: flex-end;
    justify-content: center;
    padding: 1rem;
    position: relative;
    overflow: hidden;
}

.sorting-board {
    display: flex;
    align-items: flex-end;
    justify-content: center;
    width: 100%;
    height: 100%;
    gap: 4px;
}

.sort-bar {
    flex-grow: 1;
    background: linear-gradient(to top, var(--color-primary), #a78bfa);
    border-radius: 4px 4px 0 0;
    transition: height 0.1s ease, background-color 0.1s ease;
    position: relative;
    display: flex;
    justify-content: center;
}

.sort-bar-value {
    position: absolute;
    bottom: -22px;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-muted);
    font-family: var(--font-mono);
}

.sort-bar.comparing {
    background: linear-gradient(to top, var(--color-accent), #f472b6) !important;
    box-shadow: 0 0 10px var(--color-accent-glow);
}

.sort-bar.swapping {
    background: linear-gradient(to top, var(--color-secondary), #22d3ee) !important;
    box-shadow: 0 0 10px var(--color-secondary-glow);
}

.sort-bar.sorted {
    background: linear-gradient(to top, var(--color-success), #34d399) !important;
}

.sort-bar.pivot {
    background: linear-gradient(to top, var(--color-warning), #fbbf24) !important;
}

.explanation-container {
    background-color: rgba(255, 255, 255, 0.01);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.25rem;
}

.explanation-container h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.small-desc {
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-bottom: 1rem;
}

.array-diagram {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
    padding: 0.75rem;
    background-color: #07090e;
    border-radius: 8px;
    border: 1px solid rgba(255, 255, 255, 0.03);
    min-height: 60px;
}

.diagram-node {
    display: flex;
    flex-direction: column;
    align-items: center;
    background-color: #121824;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 0.4rem 0.75rem;
    font-family: var(--font-mono);
    min-width: 45px;
    transition: all 0.2s ease;
}

.diagram-node.active-check {
    border-color: var(--color-accent);
    box-shadow: 0 0 8px var(--color-accent-glow);
    background-color: rgba(236, 72, 153, 0.05);
}

.diagram-node.active-swap {
    border-color: var(--color-secondary);
    box-shadow: 0 0 8px var(--color-secondary-glow);
    background-color: rgba(6, 182, 212, 0.05);
}

.diagram-node.active-sorted {
    border-color: var(--color-success);
    background-color: rgba(16, 185, 129, 0.05);
}

.diagram-node-val {
    font-size: 0.95rem;
    font-weight: bold;
    color: #ffffff;
}

.diagram-node-idx {
    font-size: 0.7rem;
    color: var(--text-dark);
    margin-top: 0.2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    width: 100%;
    text-align: center;
    padding-top: 0.15rem;
}

.scroll-desc {
    max-height: 250px;
    overflow-y: auto;
    padding-right: 0.25rem;
}

.scroll-desc p {
    font-size: 0.9rem;
    line-height: 1.5;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
}

.complexity-table {
    width: 100%;
    font-size: 0.9rem;
}

.complexity-table td {
    padding: 0.5rem 0;
}

.complexity-table td:first-child {
    color: var(--text-muted);
}

.complexity-table td:last-child {
    text-align: right;
    font-weight: 600;
}

.complexity-table code {
    font-family: var(--font-mono);
    background-color: #121824;
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    color: var(--color-primary);
}

.badge-property {
    background-color: rgba(16, 185, 129, 0.1);
    color: var(--color-success);
    border: 1px solid rgba(16, 185, 129, 0.25);
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: 600;
}

.canvas-container {
    height: auto;
    padding: 0.5rem;
    background-color: #070a11;
}

.canvas-wrapper {
    position: relative;
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
}

canvas {
    max-width: 100%;
    border-radius: 8px;
    background-color: #090e1a;
    display: block;
}

.canvas-legend {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 1rem;
    font-size: 0.85rem;
    color: var(--text-muted);
    border-top: 1px solid var(--border-color);
    width: 100%;
    padding-top: 0.75rem;
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.legend-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    display: inline-block;
}

.legend-dot.start { background-color: var(--color-success); }
.legend-dot.end { background-color: var(--color-error); }
.legend-dot.visited { background-color: var(--color-secondary); }
.legend-dot.path { background-color: var(--color-primary); }

.complexity-badge-container {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.75rem;
    flex-wrap: wrap;
}

.c-badge {
    background-color: #121824;
    border: 1px solid var(--border-color);
    padding: 0.3rem 0.6rem;
    border-radius: 6px;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.c-badge strong {
    color: var(--color-primary);
    font-family: var(--font-mono);
}

.accent-title {
    color: #ffffff;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.logs-container {
    flex-grow: 1;
    overflow-y: auto;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    background-color: #07090e;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 0.85rem;
    color: var(--text-muted);
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
    min-height: 150px;
    max-height: 300px;
}

.log-line {
    line-height: 1.4;
    padding-bottom: 0.25rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.02);
}

.log-line.system { color: var(--text-dark); font-style: italic; }
.log-line.calc { color: var(--color-secondary); }
.log-line.found { color: var(--color-success); font-weight: bold; }
.log-line.update { color: var(--color-primary); }
.log-line.error { color: var(--color-error); }

.code-viewer-container {
    margin-top: 1.5rem;
    background-color: #070a12;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
}

.code-viewer-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1.25rem;
    background-color: rgba(255, 255, 255, 0.02);
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
    gap: 0.5rem;
}

.code-header-right {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.code-viewer-header h3 {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-muted);
}

.language-tabs {
    display: flex;
    gap: 0.25rem;
    background-color: #121824;
    padding: 0.2rem;
    border-radius: 6px;
    border: 1px solid var(--border-color);
}

.lang-tab {
    background: none;
    border: none;
    color: var(--text-muted);
    font-family: var(--font-sans);
    font-size: 0.8rem;
    font-weight: 600;
    padding: 0.3rem 0.75rem;
    border-radius: 4px;
    cursor: pointer;
    transition: var(--transition-fast);
}

.lang-tab.active {
    background-color: var(--color-primary);
    color: #ffffff;
}

.code-content-wrapper {
    padding: 1.25rem;
    overflow-x: auto;
    max-height: 360px;
    background-color: #05070c;
}

pre { margin: 0; }

code.fira-code {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: #e5e7eb;
    line-height: 1.5;
    display: block;
}

.subtab-navigation {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
    overflow-x: auto;
}

.subtab-btn {
    background: none;
    border: none;
    color: var(--text-muted);
    font-family: var(--font-sans);
    font-size: 1.05rem;
    font-weight: 600;
    padding: 0.5rem 1rem;
    cursor: pointer;
    position: relative;
    transition: var(--transition-fast);
    white-space: nowrap;
}

.subtab-btn:hover { color: #ffffff; }
.subtab-btn.active { color: var(--color-primary); }

.subtab-btn.active::after {
    content: '';
    position: absolute;
    bottom: -9px;
    left: 0;
    right: 0;
    height: 3px;
    background-color: var(--color-primary);
    border-radius: 3px 3px 0 0;
    box-shadow: 0 0 10px var(--color-primary-glow);
}

.subtab-view { display: none; }
.subtab-view.active { display: block; }

.chess-container {
    height: auto;
    padding: 1.5rem;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #07090e;
    overflow-x: auto;
}

.nqueens-board {
    display: grid;
    border: 2px solid var(--border-color);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
    border-radius: 8px;
    overflow: hidden;
}

.chess-cell {
    width: clamp(30px, 6vw, 48px);
    height: clamp(30px, 6vw, 48px);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: clamp(1.2rem, 3.5vw, 1.8rem);
    position: relative;
    transition: background-color 0.15s ease;
}

.chess-cell.light { background-color: #1e293b; }
.chess-cell.dark { background-color: #0f172a; }
.chess-cell.queen-placed { background-color: rgba(16, 185, 129, 0.25) !important; }
.chess-cell.checking { background-color: rgba(245, 158, 11, 0.3) !important; }
.chess-cell.conflict {
    background-color: rgba(239, 68, 68, 0.45) !important;
    animation: cell-shake 0.2s 2;
}




@keyframes cell-shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-4px); }
    75% { transform: translateX(4px); }
}

.queen-img {
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.5));
    animation: queen-pop 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 2;
    user-select: none;
}

@keyframes queen-pop {
    0% { transform: scale(0); }
    100% { transform: scale(1); }
}

.toast {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background-color: var(--color-primary);
    color: #ffffff;
    padding: 0.75rem 1.25rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.9rem;
    box-shadow: 0 4px 15px var(--color-primary-glow);
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 200;
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

/* ----------------------------------------------------
   RESPONSIVE MEDIA QUERIES (TABLETS & PHONES)
   ---------------------------------------------------- */
@media (max-width: 1024px) {
    .dashboard-layout {
        grid-template-columns: 1fr;
    }
    
    .main-content {
        padding: 1.75rem;
    }
}

@media (max-width: 768px) {
    .mobile-header {
        display: flex;
    }
    
    .sidebar {
        position: fixed;
        top: 60px;
        left: 0;
        bottom: 0;
        width: 280px;
        transform: translateX(-100%);
        box-shadow: 4px 0 25px rgba(0, 0, 0, 0.5);
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .sidebar-brand {
        display: none;
    }
    
   .main-content {
      padding: 1.25rem;
      height: calc(100vh - 60px);
   }
    
    .hero-section {
        padding: 2.5rem 1.5rem;
    }
    
    .hero-text h1 {
        font-size: 2rem;
    }
    
    .typewriter-container {
        font-size: 0.95rem;
        padding: 0.5rem 0.85rem;
    }
    
    .control-bar {
        flex-direction: column;
        align-items: stretch;
    }
    
    .btn-group {
        margin-left: 0;
        width: 100%;
        justify-content: space-between;
    }
    
    .btn {
        flex-grow: 1;
        justify-content: center;
    }

    input[type="range"] {
        width: 100%;
    }

    .nqueens-board {
        grid-template-columns: repeat(var(--nq-cols, 8), clamp(28px, 8vw, 40px)) !important;
        grid-template-rows: repeat(var(--nq-rows, 8), clamp(28px, 8vw, 40px)) !important;
    }
}