:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-card: #1a1a25;
    --bg-card-hover: #222230;
    --bg-tertiary: #252535;
    --bg-hover: #2a2a3a;

    --text-primary: #ffffff;
    --text-secondary: #a0a0b0;
    --text-muted: #6b6b7b;

    --accent-purple: #8b5cf6;
    --accent-purple-light: #a78bfa;
    --accent-purple-dark: #7c3aed;
    --accent-blue: #6366f1;
    --accent-pink: #ec4899;
    --accent-gradient: linear-gradient(135deg, #8b5cf6 0%, #6366f1 50%, #ec4899 100%);
    
    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --glow-primary: rgba(99, 102, 241, 0.5);
    --glow-secondary: rgba(139, 92, 246, 0.3);

    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;

    --border-color: rgba(255,255,255,0.1);
    --accent-glow: rgba(139,92,246,0.4);
    --accent-glow-strong: rgba(139,92,246,0.6);

    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.4s cubic-bezier(0.4,0,0.2,1);
    --glass-bg: rgba(26,26,37,0.6);
    --glass-border: rgba(255,255,255,0.08);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
}


.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    height: 80px;
    display: flex;
    align-items: center;
    transition: var(--transition-normal);
}

.nav-container {
    max-width: 1400px;
    width: 100%;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-left {
    flex: 1;
    display: flex;
    align-items: center;
    margin-top: 13px;
}

.nav-center {
    flex: 2;
    display: flex;
    justify-content: center;
}

.nav-right {
    flex: 1;
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: 1.5rem;
}

.logo {
    text-decoration: none;
    display: flex;
    align-items: center;
}

.logo-text {
    font-size: 1.75rem;
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
    font-family: 'Times New Roman', Times, serif;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 3rem;
    align-items: center;
}

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.95rem;
    padding: 0.5rem 0;
    position: relative;
    transition: var(--transition-normal);
    white-space: nowrap;
    text-decoration: none;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-gradient);
    transition: var(--transition-normal);
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-link.active {
    font-weight: 600;
}

.nav-link.active::after {
    background: var(--accent-secondary);
    box-shadow: 0 0 15px var(--glow-secondary);
}

.location-selector {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 0.5rem 1rem;
    background: var(--bg-card);
    border-radius: 8px;
    border: 1px solid var(--border-color);
    cursor: pointer;
    transition: var(--transition-normal);
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.location-selector:hover {
    border-color: var(--accent-primary);
    box-shadow: 0 0 20px var(--glow-secondary);
    color: var(--text-primary);
}

.location-icon {
    color: var(--accent-primary);
}

.location-dropdown {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-family: inherit;
    font-size: 0.9rem;
    cursor: pointer;
    outline: none;
}

.location-dropdown option {
    background: var(--bg-card);
    color: var(--text-primary);
}


.profile-menu-wrapper {
    position: relative;
}

.profile-btn {
    width: 38px;
    height: 38px;
    border-radius: 50%;
    background: linear-gradient(135deg, #8b5cf6, #6366f1);
    border: 2px solid rgba(139, 92, 246, 0.4);
    color: white;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.profile-btn:hover {
    transform: scale(1.1);
    box-shadow: 0 0 16px rgba(139, 92, 246, 0.5);
}

.profile-dropdown {
    position: absolute;
    top: 48px;
    right: 0;
    background: #1a1a25;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    padding: 8px;
    min-width: 180px;
    display: none;
    z-index: 9999;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
}

.profile-dropdown .user-name {
    padding: 8px 12px;
    color: #a0a0b0;
    font-size: 13px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    margin-bottom: 6px;
}

.profile-dropdown button {
    display: flex;
    align-items: center;
    gap: 8px;
    width: 100%;
    padding: 9px 12px;
    border-radius: 8px;
    font-size: 14px;
    background: none;
    border: none;
    cursor: pointer;
    transition: background 0.2s;
    text-align: left;
    color: var(--text-secondary);
    font-family: inherit;
}

.profile-dropdown button:hover {
    background: rgba(139, 92, 246, 0.15);
    color: var(--text-primary);
}

.profile-dropdown .logout-item {
    color: #ef4444;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding-top: 10px;
}

.profile-dropdown .logout-item:hover {
    background: rgba(239, 68, 68, 0.1);
    color: #ef4444;
}

.login-nav-btn {
    background: linear-gradient(135deg, #8b5cf6, #6366f1);
    color: white;
    padding: 8px 18px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s;
    white-space: nowrap;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.login-nav-btn:hover {
    opacity: 0.9;
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(139, 92, 246, 0.4);
}


.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    z-index: 1100;
}

.mobile-menu-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: #fff;
    border-radius: 2px;
    transition: all 0.3s;
}

.mobile-menu {
    display: none;
    position: fixed;
    top: 80px;
    left: 0;
    right: 0;
    background: rgba(10, 10, 15, 0.98);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    z-index: 999;
    padding: 1.5rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
}

.mobile-menu.open {
    display: block;
}

.mobile-nav-links {
    list-style: none;
    padding: 0;
    margin: 0;
}

.mobile-nav-links li {
    margin-bottom: 4px;
}

.mobile-nav-links a {
    display: block;
    padding: 0.85rem 1rem;
    color: #a0a0b0;
    text-decoration: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 500;
    transition: all 0.2s;
}

.mobile-nav-links a:hover {
    background: rgba(139, 92, 246, 0.15);
    color: #fff;
}

.mobile-auth {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
}

@media (max-width: 768px) {
    .nav-center,
    .nav-right {
        display: none !important;
    }

    .mobile-menu-toggle {
        display: flex !important;
    }
}

.mobile-welcome { color: #a0a0b0; font-size: 13px; margin-bottom: 8px; }

.mobile-logout-btn {
    background: rgba(239, 68, 68, 0.15);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: #ef4444;
    padding: 8px 16px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: all 0.3s ease;
}

.mobile-logout-btn:hover { background: rgba(239, 68, 68, 0.25); }

.mobile-login-btn {
    display: block;
    text-align: center;
    background: linear-gradient(135deg, #8b5cf6, #6366f1);
    color: white;
    padding: 10px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
}

.mobile-login-btn:hover { transform: translateY(-2px); box-shadow: 0 4px 15px rgba(139, 92, 246, 0.4); }


.main-content {
    margin-top: 80px;
    min-height: calc(100vh - 80px);
    position: relative;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 3rem 2rem;
}

.page {
    display: none;
    animation: fadeInUp 0.5s ease-out;
}

.page.active {
    display: block;
}

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

.page-header {
    text-align: center;
    margin-bottom: 4rem;
}

.page-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    letter-spacing: -1px;
}

.gradient-text {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.page-subtitle {
    color: var(--text-secondary);
    font-size: 1.2rem;
    max-width: 600px;
    margin: 0 auto;
}

.breadcrumb {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 2rem;
    font-size: 0.9rem;
    color: var(--text-muted);
    flex-wrap: wrap;
}

.breadcrumb-item {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition-fast);
    cursor: pointer;
}

.breadcrumb-item:hover { color: var(--accent-purple-light); }

.breadcrumb-item.active {
    color: var(--text-primary);
    font-weight: 500;
    cursor: default;
}

.breadcrumb i {
    font-size: 0.7rem;
    color: var(--text-muted);
}


.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    padding: 2.5rem;
    transition: var(--transition-slow);
    position: relative;
    overflow: hidden;
}

.glass-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.category-card {
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    min-height: 300px;
    justify-content: center;
    gap: 1.5rem;
}

.category-card:hover {
    transform: translateY(-8px);
    border-color: rgba(139, 92, 246, 0.3);
    box-shadow: 0 20px 40px rgba(0,0,0,0.4), 0 0 40px rgba(139,92,246,0.1);
}

.card-hover-effect {
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at var(--mouse-x, 50%) var(--mouse-y, 50%), rgba(139,92,246,0.15), transparent 50%);
    opacity: 0;
    transition: var(--transition-normal);
    pointer-events: none;
}

.category-card:hover .card-hover-effect { opacity: 1; }

.card-icon {
    width: 80px;
    height: 80px;
    background: var(--bg-secondary);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: var(--accent-purple-light);
    border: 1px solid var(--border-color);
    transition: var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.card-icon::after {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--accent-gradient);
    opacity: 0;
    transition: var(--transition-normal);
}

.category-card:hover .card-icon {
    transform: scale(1.1);
    border-color: rgba(139,92,246,0.3);
    box-shadow: 0 0 30px var(--accent-glow);
}

.category-card:hover .card-icon::after { opacity: 0.1; }

.card-icon i {
    position: relative;
    z-index: 1;
    transition: var(--transition-normal);
}

.category-card:hover .card-icon i { transform: scale(1.1); }

.card-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.card-description {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 0.95rem;
}

.subcategory-card {
    cursor: pointer;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    min-height: 280px;
}

.subcategory-card:hover {
    transform: translateY(-5px);
    border-color: rgba(139,92,246,0.3);
    box-shadow: 0 15px 30px rgba(0,0,0,0.3), 0 0 30px rgba(139,92,246,0.1);
}

.card-stats {
    display: flex;
    gap: 1.5rem;
    margin-top: auto;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
    font-size: 0.85rem;
    color: var(--text-muted);
}

.card-stats span {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.card-stats i { color: var(--accent-purple-light); }


.question-container {
    max-width: 800px;
    margin: 0 auto;
}

.timer-container {
    display: flex;
    justify-content: center;
    margin-bottom: 2rem;
}

.timer {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    background: var(--bg-card);
    padding: 0.75rem 1.5rem;
    border-radius: 50px;
    border: 1px solid var(--border-color);
    font-family: 'Courier New', monospace;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.timer i {
    color: var(--accent-purple-light);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50%       { opacity: 0.6; }
}

.question-card {
    margin-bottom: 2rem;
    padding: 2.5rem;
}

.question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.question-number {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
}

.difficulty-badge {
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.difficulty-badge.easy   { background: rgba(16,185,129,0.2);  color: var(--success); border: 1px solid rgba(16,185,129,0.3); }
.difficulty-badge.medium { background: rgba(245,158,11,0.2);  color: var(--warning); border: 1px solid rgba(245,158,11,0.3); }
.difficulty-badge.hard   { background: rgba(239,68,68,0.2);   color: var(--error);   border: 1px solid rgba(239,68,68,0.3);  }

.question-text {
    font-size: 1.25rem;
    line-height: 1.6;
    color: var(--text-primary);
    font-weight: 500;
}

/* Options */
.options-grid {
    display: grid;
    gap: 1rem;
    margin-bottom: 2rem;
}

.option-card {
    display: flex;
    align-items: center;
    gap: 1.25rem;
    padding: 1.5rem;
    cursor: pointer;
    transition: var(--transition-normal);
    background: var(--glass-bg);
}

.option-card:hover {
    background: rgba(139,92,246,0.1);
    border-color: rgba(139,92,246,0.3);
    transform: translateX(8px);
    box-shadow: 0 5px 20px rgba(139,92,246,0.1);
}

.option-letter {
    width: 40px;
    height: 40px;
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    color: var(--accent-purple-light);
    transition: var(--transition-normal);
    flex-shrink: 0;
}

.option-card:hover .option-letter {
    border-color: var(--accent-purple);
    background: rgba(139,92,246,0.1);
    box-shadow: 0 0 15px var(--accent-glow);
}

.option-text { font-size: 1rem; color: var(--text-primary); }

.option-card.selected { background: rgba(139,92,246,0.15); border-color: var(--accent-purple); }
.option-card.selected .option-letter { background: var(--accent-purple); color: white; border-color: var(--accent-purple); }
.option-card.correct  { background: rgba(16,185,129,0.15); border-color: var(--success); animation: correctPulse 0.5s ease; }
.option-card.correct  .option-letter { background: var(--success); color: white; border-color: var(--success); }
.option-card.wrong    { background: rgba(239,68,68,0.15);   border-color: var(--error);   animation: shake 0.5s ease; }
.option-card.wrong    .option-letter { background: var(--error);   color: white; border-color: var(--error); }

@keyframes correctPulse { 0%, 100% { transform: scale(1); } 50% { transform: scale(1.02); } }
@keyframes shake { 0%, 100% { transform: translateX(0); } 25% { transform: translateX(-10px); } 75% { transform: translateX(10px); } }


.feedback-section {
    margin-bottom: 2rem;
    animation: slideDown 0.4s ease-out;
}

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

.answer-feedback {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1.5rem;
    border-radius: 16px;
    margin-bottom: 1rem;
    border: 1px solid transparent;
}

.answer-feedback.correct { background: rgba(16,185,129,0.1); border-color: rgba(16,185,129,0.3); }
.answer-feedback.wrong   { background: rgba(239,68,68,0.1);   border-color: rgba(239,68,68,0.3); }

.feedback-icon {
    width: 50px; height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    flex-shrink: 0;
}

.answer-feedback.correct .feedback-icon { background: rgba(16,185,129,0.2); color: var(--success); }
.answer-feedback.wrong   .feedback-icon { background: rgba(239,68,68,0.2);  color: var(--error); }

.feedback-content h3 { font-size: 1.2rem; margin-bottom: 0.25rem; }
.answer-feedback.correct .feedback-content h3 { color: var(--success); }
.answer-feedback.wrong   .feedback-content h3 { color: var(--error); }
.feedback-content p { color: var(--text-secondary); font-size: 0.9rem; }

.explanation-card { background: rgba(255,255,255,0.03); border-left: 4px solid var(--accent-purple); }
.explanation-card h4 { display: flex; align-items: center; gap: 0.5rem; margin-bottom: 1rem; color: var(--accent-purple-light); font-size: 1rem; }
.explanation-card h4 i { color: var(--warning); }
.explanation-card p { color: var(--text-secondary); line-height: 1.8; font-size: 0.95rem; }


.notepad-container {
    margin-bottom: 2rem;
    background: var(--bg-secondary);
    border-radius: 20px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    box-shadow: 0 10px 40px rgba(0,0,0,0.4);
}

.notepad-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
}

.notepad-header h4 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 600;
}

.clear-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    padding: 0.5rem 1rem;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.85rem;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.clear-btn:hover { background: rgba(239,68,68,0.1); border-color: rgba(239,68,68,0.3); color: var(--error); }

.notepad-wrapper { position: relative; background: #ffffff; }

.drawing-canvas {
    width: 100%;
    height: 300px;
    background: #ffffff;
    cursor: crosshair;
    display: block;
}

.notepad-toolbar {
    position: absolute;
    bottom: 1rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(255,255,255,0.95);
    padding: 0.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.15);
    border: 1px solid #e0e0e0;
}

.tool-btn {
    width: 40px; height: 40px;
    border: none;
    background: transparent;
    border-radius: 8px;
    cursor: pointer;
    color: #666;
    font-size: 1rem;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.tool-btn:hover  { background: #f0f0f0; color: #333; }
.tool-btn.active { background: var(--accent-purple); color: white; }

.toolbar-divider { width: 1px; height: 24px; background: #ddd; margin: 0 0.25rem; }

.color-picker {
    width: 32px; height: 32px;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    background: none;
    padding: 2px;
    border: 2px solid #ddd;
}


.navigation-buttons {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
    margin-top: 3rem;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 2rem;
    border-radius: 12px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition-normal);
    border: none;
    position: relative;
    overflow: hidden;
}

.prev-btn { background: var(--bg-card); color: var(--text-primary); border: 1px solid var(--border-color); }
.prev-btn:hover:not(:disabled) { background: var(--bg-hover); border-color: var(--text-secondary); transform: translateX(-4px); }

.next-btn { background: var(--accent-gradient); color: white; box-shadow: 0 4px 20px rgba(139,92,246,0.3); }
.next-btn:hover:not(:disabled) { transform: translateX(4px); box-shadow: 0 6px 30px rgba(139,92,246,0.5), 0 0 20px var(--accent-glow-strong); }

.nav-btn:disabled { opacity: 0.5; cursor: not-allowed; }



.coding-actions-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding: 1rem 1.5rem;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    animation: slideDown 0.4s ease-out;
}

.coding-timer {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-family: 'Courier New', monospace;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.coding-timer i { color: var(--accent-purple-light); animation: pulse 2s infinite; }

.coding-buttons { display: flex; gap: 1rem; }

.coding-action-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: 10px;
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    transition: var(--transition-normal);
    border: none;
    position: relative;
    overflow: hidden;
}

.run-btn { background: transparent; color: var(--text-primary); border: 2px solid var(--accent-purple); }
.run-btn:hover { background: rgba(139,92,246,0.1); box-shadow: 0 0 20px var(--accent-glow); transform: translateY(-2px); }
.run-btn i { color: var(--accent-purple-light); }

.submit-btn { background: var(--accent-gradient); color: white; box-shadow: 0 4px 15px rgba(139,92,246,0.3); }
.submit-btn:hover { transform: translateY(-2px); box-shadow: 0 6px 25px rgba(139,92,246,0.5), 0 0 20px var(--accent-glow-strong); }


.coding-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
    min-height: 600px;
}

.coding-question-panel {
    padding: 2rem;
    overflow-y: auto;
    max-height: 800px;
}

.coding-question-title {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    letter-spacing: -0.5px;
}

.coding-question-content {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 2rem;
}

.coding-question-content code {
    background: rgba(139,92,246,0.1);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    color: var(--accent-purple-light);
    font-size: 0.9em;
}

.coding-examples { margin-bottom: 2rem; }

.example-block {
    margin-bottom: 1.5rem;
    background: rgba(0,0,0,0.2);
    border-radius: 12px;
    padding: 1.25rem;
    border: 1px solid var(--border-color);
}

.example-block h4 { color: var(--text-primary); margin-bottom: 0.75rem; font-size: 0.9rem; font-weight: 600; }

.code-block { font-family: 'Courier New', monospace; font-size: 0.9rem; color: var(--text-secondary); line-height: 1.6; }
.code-block p { margin-bottom: 0.5rem; }
.code-block strong { color: var(--accent-purple-light); }

.coding-constraints { background: rgba(255,255,255,0.02); border-radius: 12px; padding: 1.25rem; border: 1px solid var(--border-color); }
.coding-constraints h4 { color: var(--text-primary); margin-bottom: 0.75rem; font-size: 0.9rem; font-weight: 600; }
.coding-constraints ul { list-style: none; padding: 0; }
.coding-constraints li { color: var(--text-secondary); font-size: 0.9rem; margin-bottom: 0.5rem; padding-left: 1.5rem; position: relative; }
.coding-constraints li::before { content: '•'; color: var(--accent-purple-light); position: absolute; left: 0.5rem; font-weight: bold; }


.coding-editor-panel { display: flex; flex-direction: column; gap: 1rem; }

.editor-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    border-radius: 16px;
}


.language-selector {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    position: relative;
    background: rgba(139,92,246,0.08);
    border: 1px solid rgba(139,92,246,0.25);
    border-radius: 10px;
    padding: 0.4rem 0.9rem;
    transition: border-color 0.2s;
}

.language-selector:hover {
    border-color: rgba(139,92,246,0.5);
}

.language-selector i:first-child {
    color: var(--accent-purple-light);
    font-size: 1rem;
}

.language-selector select {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    background: transparent;
    border: none;
    outline: none;

    color: var(--text-primary);
    font-family: 'Inter', sans-serif;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    padding-right: 1.5rem;
    color-scheme: dark;
}


.language-selector select option {
    background: #1a1a2e;
    color: #ffffff;
    font-weight: 500;
}


.language-selector select option:hover,
.language-selector select option:checked {
    background: linear-gradient(90deg, #8b5cf6, #6366f1);
    color: #ffffff;
}

.language-selector .fa-chevron-down {
    position: absolute;
    right: 10px;
    color: var(--accent-purple-light);
    font-size: 0.75rem;
    pointer-events: none;
    transition: transform var(--transition-fast);
}

.language-selector:hover .fa-chevron-down {
    transform: rotate(180deg);
}

.editor-actions { display: flex; gap: 0.5rem; }

.editor-icon-btn {
    width: 36px; height: 36px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
}

.editor-icon-btn:hover {
    background: rgba(139,92,246,0.1);
    border-color: rgba(139,92,246,0.3);
    color: var(--text-primary);
    transform: translateY(-2px);
}

.editor-container {
    flex: 1;
    background: #1e1e2e;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    overflow: hidden;
    position: relative;
    box-shadow: inset 0 2px 10px rgba(0,0,0,0.3);
}

.code-editor {
    width: 100%;
    height: 100%;
    min-height: 400px;
    background: transparent;
    border: none;
    color: #abb2bf;
    font-family: 'Fira Code', 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 14px;
    line-height: 1.6;
    padding: 1.5rem;
    resize: none;
    outline: none;
    tab-size: 4;
}

.code-editor::placeholder { color: #5c6370; }


.test-cases-container {
    padding: 1.5rem;
    max-height: 250px;
    overflow-y: auto;
}

.test-cases-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.test-cases-header h4 { display: flex; align-items: center; gap: 0.5rem; color: var(--text-primary); font-size: 1rem; font-weight: 600; }
.test-cases-header h4 i { color: var(--accent-purple-light); }

.test-status { font-size: 0.85rem; font-weight: 500; padding: 0.25rem 0.75rem; border-radius: 20px; background: rgba(255,255,255,0.05); color: var(--text-muted); }
.test-status.passed { background: rgba(16,185,129,0.2); color: var(--success); }
.test-status.failed { background: rgba(239,68,68,0.2);  color: var(--error);   }

.test-cases-list { display: flex; flex-direction: column; gap: 0.75rem; }

.test-case-item {
    background: rgba(0,0,0,0.2);
    border-radius: 12px;
    padding: 1rem;
    border: 1px solid var(--border-color);
    transition: var(--transition-fast);
}

.test-case-item:hover { border-color: rgba(139,92,246,0.3); transform: translateX(4px); }

.test-case-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 0.75rem; }
.test-case-num { font-weight: 600; color: var(--text-primary); font-size: 0.9rem; }

.test-case-status { font-size: 0.8rem; display: flex; align-items: center; gap: 0.5rem; }
.test-case-status.pending { color: var(--text-muted); }
.test-case-status.passed  { color: var(--success); }
.test-case-status.failed  { color: var(--error); }
.test-case-status i { font-size: 0.6rem; }

.test-io { display: flex; flex-direction: column; gap: 0.5rem; }
.test-input, .test-expected, .test-output { font-family: 'Courier New', monospace; font-size: 0.85rem; }
.test-input strong, .test-expected strong, .test-output strong { color: var(--text-secondary); margin-right: 0.5rem; font-weight: 600; }
.test-input code, .test-expected code, .test-output code { color: var(--accent-purple-light); background: rgba(139,92,246,0.1); padding: 0.2rem 0.4rem; border-radius: 4px; }
.test-output code.user-output { color: var(--text-primary); }


.coding-navigation {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

.coding-navigation .nav-btn { padding: 1rem 2.5rem; }


.code-editor::-webkit-scrollbar,
.test-cases-container::-webkit-scrollbar,
.coding-question-panel::-webkit-scrollbar { width: 8px; }
.code-editor::-webkit-scrollbar-track,
.test-cases-container::-webkit-scrollbar-track,
.coding-question-panel::-webkit-scrollbar-track { background: transparent; }
.code-editor::-webkit-scrollbar-thumb,
.test-cases-container::-webkit-scrollbar-thumb,
.coding-question-panel::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.1); border-radius: 4px; }
.code-editor::-webkit-scrollbar-thumb:hover,
.test-cases-container::-webkit-scrollbar-thumb:hover,
.coding-question-panel::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.2); }

@media (max-width: 968px) {
    .coding-layout { grid-template-columns: 1fr; }
    .coding-question-panel { max-height: 400px; }
    .coding-actions-bar { flex-direction: column; gap: 1rem; align-items: stretch; }
    .coding-buttons { justify-content: center; }
}

@media (max-width: 768px) {
    .cards-grid { grid-template-columns: 1fr; }
    .page-title { font-size: 2rem; }
    .coding-navigation { flex-direction: column; }
    .coding-navigation .nav-btn { width: 100%; justify-content: center; }
}


.hidden { display: none !important; }

.fade-in { animation: fadeIn 0.3s ease; }

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

::selection { background: rgba(139,92,246,0.3); color: var(--text-primary); }

button:focus-visible, select:focus-visible, textarea:focus-visible {
    outline: 2px solid var(--accent-purple);
    outline-offset: 2px;
}


.sraaza-modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.6);
    backdrop-filter: blur(6px);
    z-index: 99998;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    animation: sraazaFadeIn 0.25s ease forwards;
}

@keyframes sraazaFadeIn {
    to { opacity: 1; }
}

.sraaza-modal {
    background: linear-gradient(145deg, #1a1a2e 0%, #16162a 100%);
    border: 1px solid rgba(139,92,246,0.3);
    border-radius: 20px;
    padding: 2rem 2.5rem;
    max-width: 420px;
    width: calc(100% - 3rem);
    box-shadow: 0 24px 80px rgba(0,0,0,0.7), 0 0 0 1px rgba(255,255,255,0.04), 0 0 60px rgba(139,92,246,0.12);
    transform: translateY(20px) scale(0.96);
    animation: sraazaSlideUp 0.3s cubic-bezier(0.34,1.56,0.64,1) forwards;
    text-align: center;
}

@keyframes sraazaSlideUp {
    to { transform: translateY(0) scale(1); }
}

.sraaza-modal-icon {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    margin: 0 auto 1.25rem;
}

.sraaza-modal-icon.success {
    background: rgba(16,185,129,0.15);
    border: 2px solid rgba(16,185,129,0.35);
    color: #10b981;
    box-shadow: 0 0 30px rgba(16,185,129,0.2);
}

.sraaza-modal-icon.error {
    background: rgba(239,68,68,0.15);
    border: 2px solid rgba(239,68,68,0.35);
    color: #ef4444;
    box-shadow: 0 0 30px rgba(239,68,68,0.2);
}

.sraaza-modal-icon.info {
    background: rgba(139,92,246,0.15);
    border: 2px solid rgba(139,92,246,0.35);
    color: #a78bfa;
    box-shadow: 0 0 30px rgba(139,92,246,0.2);
}

.sraaza-modal-title {
    font-size: 1.2rem;
    font-weight: 700;
    color: #fff;
    margin-bottom: 0.5rem;
    letter-spacing: -0.3px;
}

.sraaza-modal-message {
    font-size: 0.95rem;
    color: #a0a0b0;
    line-height: 1.6;
    margin-bottom: 1.75rem;
}

.sraaza-modal-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 0.75rem 2rem;
    border-radius: 12px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    border: none;
    font-family: 'Inter', sans-serif;
    transition: all 0.2s ease;
    min-width: 120px;
}

.sraaza-modal-btn.success {
    background: linear-gradient(135deg, #10b981, #059669);
    color: #fff;
    box-shadow: 0 4px 20px rgba(16,185,129,0.35);
}

.sraaza-modal-btn.success:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(16,185,129,0.5);
}

.sraaza-modal-btn.error {
    background: linear-gradient(135deg, #ef4444, #dc2626);
    color: #fff;
    box-shadow: 0 4px 20px rgba(239,68,68,0.35);
}

.sraaza-modal-btn.error:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(239,68,68,0.5);
}

.sraaza-modal-btn.info {
    background: linear-gradient(135deg, #8b5cf6, #6366f1);
    color: #fff;
    box-shadow: 0 4px 20px rgba(139,92,246,0.35);
}

.sraaza-modal-btn.info:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(139,92,246,0.5);
}


.sraaza-toast-container {
    position: fixed;
    top: 24px;
    right: 24px;
    z-index: 99999;
    display: flex;
    flex-direction: column;
    gap: 10px;
    pointer-events: none;
}

.sraaza-toast {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 20px;
    border-radius: 14px;
    background: #1a1a2e;
    border: 1px solid rgba(255,255,255,0.1);
    box-shadow: 0 8px 32px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.04);
    min-width: 280px;
    max-width: 380px;
    pointer-events: all;
    animation: toastSlideIn 0.35s cubic-bezier(0.34,1.56,0.64,1) forwards;
    backdrop-filter: blur(12px);
}

@keyframes toastSlideIn {
    from { opacity: 0; transform: translateX(40px) scale(0.95); }
    to   { opacity: 1; transform: translateX(0)    scale(1);    }
}

.sraaza-toast.removing {
    animation: toastSlideOut 0.3s ease forwards;
}

@keyframes toastSlideOut {
    to { opacity: 0; transform: translateX(40px) scale(0.95); }
}

.sraaza-toast-icon {
    width: 36px;
    height: 36px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    flex-shrink: 0;
}

.sraaza-toast.success .sraaza-toast-icon { background: rgba(16,185,129,0.2);  color: #10b981; }
.sraaza-toast.error   .sraaza-toast-icon { background: rgba(239,68,68,0.2);   color: #ef4444; }
.sraaza-toast.info    .sraaza-toast-icon { background: rgba(139,92,246,0.2);  color: #a78bfa; }
.sraaza-toast.warning .sraaza-toast-icon { background: rgba(245,158,11,0.2);  color: #f59e0b; }

.sraaza-toast.success { border-left: 3px solid #10b981; }
.sraaza-toast.error   { border-left: 3px solid #ef4444; }
.sraaza-toast.info    { border-left: 3px solid #8b5cf6; }
.sraaza-toast.warning { border-left: 3px solid #f59e0b; }

.sraaza-toast-body { flex: 1; min-width: 0; }

.sraaza-toast-title {
    font-size: 0.9rem;
    font-weight: 700;
    color: #fff;
    margin-bottom: 2px;
}

.sraaza-toast-msg {
    font-size: 0.82rem;
    color: #a0a0b0;
    line-height: 1.4;
    white-space: pre-wrap;
    word-break: break-word;
}

.sraaza-toast-close {
    width: 24px;
    height: 24px;
    border-radius: 6px;
    border: none;
    background: rgba(255,255,255,0.06);
    color: #6b6b7b;
    font-size: 0.75rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    flex-shrink: 0;
}

.sraaza-toast-close:hover { background: rgba(255,255,255,0.15); color: #fff; }


.footer {
    padding: 12px 0;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    position: relative;
}

.footer-grid {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 32px;
    margin-bottom: 10px;
}

.footer-logo {
    font-size: 1rem;
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 2px;
    display: inline-block;
}

.footer-tagline { color: var(--text-muted); font-size: 0.72rem; line-height: 1.3; max-width: 240px; }

.footer-social { display: flex; gap: 8px; }

.social-link {
    width: 30px; height: 30px;
    background: var(--bg-card);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-size: 0.85rem;
    transition: var(--transition-normal);
    border: 1px solid var(--border-color);
}

.social-link:hover { background: var(--accent-gradient); color: white; border-color: transparent; transform: translateY(-1px); }

.footer-policy-row { display: flex; align-items: center; justify-content: center; gap: 10px; padding: 6px 0 4px; }
.footer-policy-link { color: var(--text-muted); font-size: 0.72rem; text-decoration: none; transition: color 0.2s ease; }
.footer-policy-link:hover { color: var(--accent-purple-light); }
.footer-dot { color: var(--text-muted); font-size: 0.65rem; opacity: 0.4; }

.footer-bottom { text-align: center; padding-top: 6px; border-top: 1px solid var(--border-color); margin-top: 4px; }
.copyright { color: var(--text-muted); font-size: 0.72rem; }

.footer-glow {
    position: absolute;
    bottom: -60px; left: 50%;
    transform: translateX(-50%);
    width: 400px; height: 120px;
    background: var(--accent-purple);
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.08;
    pointer-events: none;
}

@media (max-width: 768px) {
    .footer-grid { flex-direction: column; text-align: center; gap: 12px; padding: 0 16px; }
    .footer-tagline { max-width: 100%; }
    .footer-dot { display: none; }
}
.language-selector select {
    background-color: #1a1a2e !important;
    color: #ffffff !important;
    color-scheme: dark;
}
 

.language-selector select option,
#language-select option {
    background-color: #1a1a2e !important;
    background: #1a1a2e !important;
    color: #ffffff !important;
}
 

.language-selector select option:checked,
.language-selector select option:hover,
#language-select option:checked,
#language-select option:hover {
    background-color: #8b5cf6 !important;
    background: #8b5cf6 !important;
    color: #ffffff !important;
}
.footer-logo-wrap {
    display: flex;
    align-items: center;
    gap: 6px;
    margin-bottom: 4px;
}
.footer-logo-img {
    height: 24px;
    width: auto;
    margin-top: -18px;
    margin-right: -12px;
    display: block;
}
.footer-logo-text {
    font-size: 1rem;
    font-weight: 800;
    background: linear-gradient(135deg, #ec4899, #8b5cf6, #6366f1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
    font-family: 'Times New Roman', Times, serif;
}