:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --success-color: #10b981;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --background-color: #f8fafc;
    --card-background: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.5;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.app-container {
    width: 100%;
    max-width: 800px;
    background: var(--card-background);
    border-radius: 12px;
    box-shadow: var(--shadow);
    overflow: hidden;
    min-height: 600px;
    position: relative;
    transition: filter 0.3s ease;
}

/* Auth Overlay */
.auth-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    display: flex;
    justify-content: center;
    align-items: center;
}

.auth-box {
    background: white;
    padding: 40px;
    border-radius: 12px;
    width: 100%;
    max-width: 400px;
    box-shadow: 0 20px 25px -5px rgb(0 0 0 / 0.1);
    text-align: center;
}

.auth-box h2 {
    color: var(--primary-color);
    margin-bottom: 10px;
}

.auth-box p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    font-size: 0.9rem;
}

.form-group {
    margin-bottom: 15px;
    text-align: left;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
    font-size: 0.9rem;
}

.form-group input {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 1rem;
}

.btn-full {
    width: 100%;
    margin-bottom: 10px;
}

.divider {
    margin: 15px 0;
    color: var(--text-secondary);
    font-size: 0.8rem;
    font-weight: 600;
}

.btn-link {
    background: none;
    border: none;
    color: var(--text-secondary);
    text-decoration: underline;
    cursor: pointer;
    font-size: 0.9rem;
}

.error-msg {
    color: var(--error-color);
    font-size: 0.85rem;
    margin-bottom: 10px;
    min-height: 1.2em;
}

/* Dashboard Styles */
.dashboard {
    padding: 40px;
    text-align: center;
    position: relative;
}

.header-user {
    position: absolute;
    top: 20px;
    right: 20px;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.btn-sm {
    padding: 4px 8px;
    font-size: 0.8rem;
    background: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
}

.dashboard h1 {
    font-size: 2.5rem;
    margin-top: 20px;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
    margin: 30px 0;
}

.stat-card {
    padding: 15px;
    background: var(--background-color);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.stat-number {
    display: block;
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

/* Topic Filters */
.topic-section {
    margin: 30px 0;
    text-align: left;
}

.topic-section h3 {
    margin-bottom: 15px;
    font-size: 1.1rem;
    color: var(--text-primary);
}

.topic-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.topic-btn {
    padding: 8px 16px;
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s;
}

.topic-btn:hover {
    border-color: var(--primary-color);
    background: #f0f9ff;
}

.topic-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.action-buttons {
    display: flex;
    flex-direction: column;
    gap: 12px;
    max-width: 400px;
    margin: 0 auto;
}

.btn-group {
    display: flex;
    gap: 10px;
}

.btn-group .btn {
    flex: 1;
}

.btn {
    padding: 12px 24px;
    border-radius: 6px;
    border: none;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

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

.btn-outline {
    background-color: transparent;
    border: 2px solid var(--border-color);
    color: var(--text-primary);
}

.btn-outline:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-outline.danger:hover {
    border-color: var(--error-color);
    color: var(--error-color);
}

/* Quiz Interface Styles */
.quiz-interface {
    display: none;
    padding: 30px;
    height: 100%;
    flex-direction: column;
}

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border-color);
}

.topic-badge {
    background: var(--background-color);
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-weight: 600;
}

.btn-icon {
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    border-radius: 4px;
    color: var(--text-secondary);
    font-weight: 600;
}

.btn-icon:hover {
    background-color: var(--background-color);
}

.btn-flag.active {
    color: var(--warning-color);
}

.question-text {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 20px;
}

.options-grid {
    display: grid;
    gap: 10px;
}

/* RENAMED .option-card TO .option-btn TO MATCH JS */
.option-btn {
    padding: 15px 20px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    background: white;
    text-align: left;
    font-size: 1rem;
    width: 100%;
    display: block;
}

.option-btn:hover:not(:disabled) {
    border-color: var(--primary-color);
    background-color: #eff6ff;
}

/* Added !important to force colors over disabled state */
.option-btn.correct {
    border-color: var(--success-color) !important;
    background-color: #ecfdf5 !important;
    color: #065f46 !important;
}

.option-btn.incorrect {
    border-color: var(--error-color) !important;
    background-color: #fef2f2 !important;
    color: #991b1b !important;
}

.option-btn:disabled {
    cursor: default;
    /* opacity: 0.7; Removed to make colors pop */
}

.explanation-box {
    margin-top: 20px;
    padding: 15px;
    background-color: #f3f4f6;
    border-left: 4px solid var(--secondary-color);
    border-radius: 4px;
}

.explanation-box h4 {
    margin-bottom: 5px;
    font-size: 0.9rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.quiz-footer {
    padding-top: 20px;
    margin-top: auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.feedback-msg {
    font-weight: 600;
}

.feedback-msg.correct {
    color: var(--success-color);
}

.feedback-msg.incorrect {
    color: var(--error-color);
}

@media (max-width: 600px) {
    .app-container {
        border-radius: 0;
        min-height: 100vh;
    }

    .topic-grid {
        flex-wrap: nowrap;
        overflow-x: auto;
        padding-bottom: 5px;
    }
}

/* Paywall UI */
.badge-premium {
    background: linear-gradient(45deg, #f59e0b, #d97706);
    color: white;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 700;
    margin-left: 10px;
}

#paywall-overlay ul li {
    margin-bottom: 10px;
    font-size: 1rem;
    color: var(--text-primary);
}

#timer-display {
    font-family: monospace;
    font-size: 1.5rem;
    padding: 5px 10px;
    background: #fef2f2;
    border: 1px solid var(--error-color);
    border-radius: 4px;
}

/* Updated Button Styles */
.btn-primary[style*="warning-color"] {
    box-shadow: 0 4px 6px -1px rgba(245, 158, 11, 0.4);
    transition: transform 0.2s;
}

.btn-primary[style*="warning-color"]:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(245, 158, 11, 0.5);
}

/* form-select */
.form-select {
    width: 100%;
    padding: 10px;
    margin-bottom: 10px;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-size: 1rem;
    background-color: white;
}