* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}

:root {
    --primary: #6c5ce7;
    --secondary: #a463f5;
    --success: #00b894;
    --danger: #d63031;
    --warning: #fdcb6e;
    --dark: #2d3436;
    --light: #f5f6fa;
    --gray: #636e72;
    --border: #dfe6e9;
    --shadow: 0 10px 30px rgba(0,0,0,0.1);
}

body {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    min-height: 100vh;
}

.app-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding: 20px;
    background: rgba(255,255,255,0.95);
    border-radius: 15px;
    box-shadow: var(--shadow);
}

.header-left h1 {
    font-size: 2rem;
    color: var(--primary);
}

.header-left h1 i {
    margin-right: 10px;
}

.subtitle {
    color: var(--gray);
    font-size: 0.9rem;
}

.high-score {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    background: var(--light);
    border-radius: 8px;
}

.high-score i {
    color: var(--warning);
    font-size: 1.2rem;
}

.high-score span {
    font-weight: 700;
    font-size: 1.2rem;
}

/* Main Content */
main {
    flex: 1;
}

.screen {
    display: none;
}

.screen.active {
    display: block;
}

/* Start Screen */
.welcome-card {
    background: white;
    border-radius: 20px;
    padding: 40px;
    text-align: center;
    box-shadow: var(--shadow);
}

.welcome-card i {
    font-size: 4rem;
    color: var(--primary);
    margin-bottom: 20px;
}

.welcome-card h2 {
    font-size: 2rem;
    margin-bottom: 10px;
}

.welcome-card p {
    color: var(--gray);
    margin-bottom: 30px;
}

.setup-form {
    max-width: 500px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: 20px;
    text-align: left;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
}

.form-group label i {
    margin-right: 8px;
    color: var(--primary);
}

.form-control {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.btn-primary {
    width: 100%;
    padding: 15px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(108, 92, 231, 0.3);
}

/* Quiz Screen */
.quiz-header {
    background: white;
    border-radius: 15px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

.progress-container {
    height: 10px;
    background: var(--border);
    border-radius: 5px;
    margin-bottom: 15px;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    width: 0%;
    transition: width 0.3s;
}

.quiz-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 15px;
    background: var(--light);
    border-radius: 8px;
}

.stat-item i {
    color: var(--primary);
}

.timer {
    background: linear-gradient(135deg, var(--warning), #f39c12);
    color: white;
}

.timer i {
    color: white;
}

.quiz-content {
    background: white;
    border-radius: 15px;
    padding: 30px;
    box-shadow: var(--shadow);
}

.question-container {
    margin-bottom: 30px;
}

#questionText {
    font-size: 1.5rem;
    margin-bottom: 15px;
    line-height: 1.5;
}

.category-badge {
    display: inline-block;
    padding: 5px 15px;
    background: var(--light);
    border-radius: 20px;
    font-size: 0.9rem;
    color: var(--gray);
}

.options-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.option-btn {
    padding: 15px 20px;
    background: var(--light);
    border: 2px solid transparent;
    border-radius: 10px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s;
    text-align: left;
}

.option-btn:hover:not(:disabled) {
    background: var(--primary);
    color: white;
    transform: translateY(-2px);
}

.option-btn.correct {
    background: var(--success);
    color: white;
    border-color: var(--success);
}

.option-btn.incorrect {
    background: var(--danger);
    color: white;
    border-color: var(--danger);
}

.option-btn.selected {
    border-color: var(--primary);
}

.option-btn:disabled {
    cursor: not-allowed;
    opacity: 0.7;
}

/* Results Screen */
.results-card {
    background: white;
    border-radius: 20px;
    padding: 40px;
    text-align: center;
    box-shadow: var(--shadow);
}

.results-icon {
    font-size: 4rem;
    color: var(--warning);
    margin-bottom: 20px;
}

.results-card h2 {
    font-size: 2rem;
    margin-bottom: 30px;
}

.score-circle {
    width: 150px;
    height: 150px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    margin: 0 auto 30px;
    color: white;
}

#finalScore {
    font-size: 3rem;
    font-weight: 700;
    line-height: 1;
}

.score-label {
    font-size: 0.9rem;
    opacity: 0.9;
}

.results-stats {
    max-width: 300px;
    margin: 0 auto 30px;
}

.result-item {
    display: flex;
    align-items: center;
    padding: 10px 0;
    border-bottom: 1px solid var(--border);
}

.result-item i {
    width: 30px;
    font-size: 1.2rem;
}

.result-item i.correct {
    color: var(--success);
}

.result-item i.incorrect {
    color: var(--danger);
}

.result-label {
    flex: 1;
    text-align: left;
}

.result-value {
    font-weight: 700;
    font-size: 1.2rem;
}

.high-score-message {
    background: linear-gradient(135deg, var(--warning), #f39c12);
    color: white;
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 20px;
    display: none;
}

.high-score-message i {
    margin-right: 8px;
}

.results-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.btn-secondary {
    padding: 15px;
    background: var(--light);
    color: var(--dark);
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-secondary:hover {
    background: var(--border);
}

/* Footer */
footer {
    text-align: center;
    color: white;
    margin-top: 30px;
}

footer .small {
    font-size: 0.8rem;
    opacity: 0.8;
    margin-top: 5px;
}

/* Loading Spinner */
.loading-spinner {
    text-align: center;
    padding: 40px;
}

.loading-spinner i {
    font-size: 3rem;
    color: var(--primary);
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Responsive */
@media (max-width: 768px) {
    .options-container {
        grid-template-columns: 1fr;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .quiz-stats {
        flex-wrap: wrap;
        gap: 10px;
    }
    
    .stat-item {
        flex: 1;
        min-width: 120px;
    }
}