/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #1a1a1a;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    overflow-x: hidden;
}

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

/* Header */
.header {
    text-align: center;
    margin-bottom: 3rem;
    padding: 2rem 0;
}

.title {
    font-size: 3rem;
    font-weight: 700;
    color: white;
    margin-bottom: 0.5rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.subtitle {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.9);
    font-weight: 300;
}

/* Main content */
.main-content {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 3rem;
    align-items: start;
}

/* Settings panel */
.settings-panel {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.setting-group {
    margin-bottom: 2.5rem;
}

.setting-group:last-child {
    margin-bottom: 0;
}

.setting-label {
    display: block;
    font-size: 1.1rem;
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 1rem;
}

/* Level selector */
.level-selector {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.level-btn {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    padding: 1rem 1.5rem;
    border: 2px solid #e2e8f0;
    border-radius: 12px;
    background: white;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
}

.level-btn:hover {
    border-color: #667eea;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.15);
}

.level-btn.active {
    border-color: #667eea;
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
}

.level-title {
    font-size: 1rem;
    font-weight: 600;
}

.level-desc {
    font-size: 0.85rem;
    opacity: 0.8;
    margin-top: 0.25rem;
}

/* Categories grid */
.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 1rem;
}

.category-item {
    cursor: pointer;
}

.category-checkbox {
    display: none;
}

.category-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1.5rem 1rem;
    border: 2px solid #e2e8f0;
    border-radius: 16px;
    background: white;
    transition: all 0.3s ease;
    text-align: center;
}

.category-item:hover .category-card {
    border-color: #667eea;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.15);
}

.category-checkbox:checked + .category-card {
    border-color: #667eea;
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
}

.category-icon {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.category-name {
    font-size: 0.9rem;
    font-weight: 500;
}

/* Question section */
.question-section {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.question-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 3rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    min-height: 200px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.question-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, #667eea, #764ba2);
}

.question-text {
    font-size: 1.3rem;
    line-height: 1.6;
    color: #2d3748;
    text-align: center;
    font-weight: 400;
}

.question-meta {
    margin-top: 1rem;
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.meta-tag {
    padding: 0.25rem 0.75rem;
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

/* Controls */
.controls {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 2rem;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.5);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.9);
    color: #667eea;
    border: 2px solid #667eea;
}

.btn-secondary:hover {
    background: #667eea;
    color: white;
    transform: translateY(-2px);
}

.btn-icon {
    font-size: 1.1rem;
}

/* Favorites */
.favorites-toggle {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    border: none;
    cursor: pointer;
    box-shadow: 0 4px 20px rgba(102, 126, 234, 0.4);
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    z-index: 1000;
}

.favorites-toggle:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 25px rgba(102, 126, 234, 0.5);
}

.favorites-count {
    position: absolute;
    top: -5px;
    right: -5px;
    background: #ff4757;
    color: white;
    border-radius: 50%;
    width: 20px;
    height: 20px;
    font-size: 0.7rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
}

.favorites-panel {
    position: fixed;
    top: 0;
    right: -400px;
    width: 400px;
    height: 100vh;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: -8px 0 32px rgba(0, 0, 0, 0.1);
    transition: right 0.3s ease;
    z-index: 1001;
    overflow-y: auto;
}

.favorites-panel.open {
    right: 0;
}

.favorites-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 2rem;
    border-bottom: 1px solid #e2e8f0;
}

.favorites-header h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: #2d3748;
}

.close-btn {
    background: none;
    border: none;
    font-size: 2rem;
    color: #718096;
    cursor: pointer;
    padding: 0;
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.favorites-list {
    padding: 1rem;
}

.empty-state {
    text-align: center;
    color: #718096;
    padding: 3rem 1rem;
    font-style: italic;
}

.favorite-item {
    background: white;
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    border-left: 4px solid #667eea;
    position: relative;
}

.favorite-question {
    font-size: 1rem;
    line-height: 1.5;
    color: #2d3748;
    margin-bottom: 0.5rem;
}

.favorite-meta {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-bottom: 1rem;
}

.remove-favorite {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: none;
    border: none;
    color: #e53e3e;
    cursor: pointer;
    font-size: 1.2rem;
    padding: 0.25rem;
    border-radius: 4px;
    transition: background-color 0.2s;
}

.remove-favorite:hover {
    background: rgba(229, 62, 62, 0.1);
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.question-card.animate {
    animation: fadeIn 0.5s ease;
}

/* Responsive design */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    .title {
        font-size: 2rem;
    }
    
    .main-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .categories-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .level-selector {
        flex-direction: row;
        overflow-x: auto;
        gap: 1rem;
    }
    
    .level-btn {
        min-width: 120px;
        flex-shrink: 0;
    }
    
    .question-card {
        padding: 2rem;
    }
    
    .question-text {
        font-size: 1.1rem;
    }
    
    .controls {
        flex-direction: column;
    }
    
    .favorites-panel {
        width: 100vw;
        right: -100vw;
    }
    
    .favorites-toggle {
        bottom: 1rem;
        right: 1rem;
        width: 50px;
        height: 50px;
    }
}