:root {
    /* Cores modernas - Gradiente verde */
    --primary-color: #10b981;
    --secondary-color: #059669;
    --gradient-bg: linear-gradient(135deg, #10b981 0%, #059669 100%);
    --gradient-card: linear-gradient(135deg, #ffffff 0%, #f0fdf4 100%);
    --card-bg: #ffffff;
    --text-dark: #2d3748;
    --text-light: #4a5568;
    --border-color: #d1fae5;
    --correct-color: #10b981;
    --correct-bg: #f0fdf4;
    --incorrect-color: #f56565;
    --incorrect-bg: #fff5f5;
    --timer-bg: #d1fae5;
    --button-primary: #10b981;
    --button-hover: #059669;
    --shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 15px 35px rgba(0, 0, 0, 0.15);
    
    /* Fontes */
    --font-family: "Poppins", "Segoe UI", system-ui, sans-serif;
    
    /* Spacing system */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-xxl: 3rem;
    
    /* Border radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    
    /* Font sizes */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    
    /* Transições */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Reset e Base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background: var(--gradient-bg);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    line-height: 1.6;
    color: var(--text-dark);
    padding: var(--spacing-md);
    background-attachment: fixed;
}

/* Container Principal */
.quiz-app {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
}

/* Telas (Start, Quiz, Score) */
.start-screen,
.score-container,
#display-container {
    background: var(--gradient-card);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow);
    overflow: hidden;
    animation: fadeInUp 0.6s ease-out;
}

.start-screen,
.score-container {
    padding: var(--spacing-xxl);
    text-align: center;
    width: 100%;
}

.start-content,
.score-content {
    max-width: 500px;
    margin: 0 auto;
}

.start-screen h1,
.score-container h2 {
    color: var(--text-dark);
    margin-bottom: var(--spacing-lg);
    font-size: var(--text-3xl);
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.start-screen p {
    color: var(--text-light);
    margin-bottom: var(--spacing-xl);
    font-size: var(--text-lg);
    line-height: 1.8;
}

.features-list {
    list-style: none;
    margin-bottom: var(--spacing-xl);
    text-align: left;
    display: inline-block;
}

.features-list li {
    padding: var(--spacing-xs) 0;
    color: var(--text-light);
    font-size: var(--text-base);
}

/* Quiz Container */
#display-container {
    width: 100%;
}

/* Quiz Header */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    background: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.number-of-count {
    font-weight: 600;
    color: var(--text-light);
    font-size: var(--text-base);
}

.timer-div {
    background: var(--timer-bg);
    border: 2px solid #bee3f8;
    border-radius: var(--radius-full);
    padding: var(--spacing-sm) var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    min-width: 120px;
    justify-content: center;
    transition: var(--transition);
}

.timer-div.warning {
    background: #fff5f5;
    border-color: #fed7d7;
    animation: pulse 1s infinite;
}

.timer-div svg {
    width: 20px;
    height: 20px;
}

.time-left {
    font-weight: 700;
    color: #2b6cb0;
    font-size: var(--text-base);
}

.timer-div.warning .time-left {
    color: #c53030;
}

/* Conteúdo do Quiz */
.quiz-content {
    padding: calc(var(--spacing-xxl) * 0.8);
}

.question {
    font-size: var(--text-2xl);
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: calc(var(--spacing-xxl) * 0.4);
    line-height: 1.3;
    text-align: center;
    padding: var(--spacing-md) 0;
}

/* Container de Opções */
.options-container {
    display: grid;
    gap: calc(var(--spacing-md) * 1.1);
    margin-bottom: calc(var(--spacing-xxl) * 0.4);
}

.option-div {
    background: #f8fafc;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: calc(var(--spacing-xl) * 0.6);
    font-size: var(--text-lg);
    text-align: left;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 600;
    color: var(--text-dark);
}

.option-div:hover:not(:disabled) {
    background: #f1f5f9;
    border-color: #cbd5e0;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.option-div:focus {
    outline: none;
    border-color: var(--button-primary);
    box-shadow: 0 0 0 3px rgba(76, 81, 191, 0.1);
}

.option-div:disabled {
    cursor: not-allowed;
    opacity: 0.7;
    transform: none !important;
}

/* Estados das Opções */
.option-div.correct {
    background: var(--correct-bg);
    border-color: var(--correct-color);
    color: var(--correct-color);
    transform: scale(1.02);
}

.option-div.incorrect {
    background: var(--incorrect-bg);
    border-color: var(--incorrect-color);
    color: var(--incorrect-color);
}

/* Buttons */
button {
    border: none;
    outline: none;
    cursor: pointer;
    font-family: inherit;
    font-weight: 600;
    transition: var(--transition);
    border-radius: var(--radius-md);
}

button:focus-visible {
    outline: 2px solid var(--button-primary);
    outline-offset: 2px;
}

#start-button,
#restart {
    background: var(--button-primary);
    color: white;
    font-size: var(--text-lg);
    padding: var(--spacing-md) var(--spacing-xl);
    min-width: 200px;
    margin-top: var(--spacing-lg);
}

#start-button:hover,
#restart:hover {
    background: var(--button-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.pulse-button {
    animation: pulse 2s infinite;
}

#next-button {
    background: var(--button-primary);
    color: white;
    font-size: var(--text-base);
    padding: var(--spacing-md) var(--spacing-xl);
    float: right;
    margin-top: var(--spacing-lg);
}

#next-button:hover:not(:disabled) {
    background: var(--button-hover);
    transform: translateY(-1px);
}

#next-button:disabled {
    background: #a0aec0;
    cursor: not-allowed;
    transform: none;
}

/* Score */
#user-score {
    font-size: var(--text-2xl);
    color: var(--text-dark);
    margin-bottom: var(--spacing-sm);
    font-weight: 700;
}

.score-message {
    font-size: var(--text-lg);
    color: var(--text-light);
    margin-bottom: var(--spacing-xl);
}

/* View States */
.hide {
    display: none !important;
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
        box-shadow: 0 0 0 0 rgba(76, 81, 191, 0.4);
    }
    50% {
        transform: scale(1.05);
    }
    70% {
        box-shadow: 0 0 0 10px rgba(76, 81, 191, 0);
    }
}

@keyframes bounceIn {
    0% {
        transform: scale(0.3);
        opacity: 0;
    }
    50% {
        transform: scale(1.05);
    }
    70% {
        transform: scale(0.9);
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

/* Responsive - Tablet */
@media (max-width: 768px) {
    :root {
        --spacing-xl: 1.5rem;
        --spacing-xxl: 2rem;
        --text-3xl: 1.5rem;
        --text-2xl: 1.25rem;
    }
    
    body {
        padding: var(--spacing-sm);
    }
    
    .quiz-app {
        max-width: 100%;
    }
    
    .start-screen,
    .score-container {
        padding: var(--spacing-xl);
    }
    
    .header {
        padding: var(--spacing-md);
        flex-direction: column;
        text-align: center;
        gap: var(--spacing-md);
    }
    
    .quiz-content {
        padding: var(--spacing-lg);
    }
    
    .question {
        font-size: var(--text-lg);
        margin-bottom: var(--spacing-lg);
    }
    
    .options-container {
        gap: var(--spacing-sm);
    }
    
    .option-div {
        padding: var(--spacing-md);
        font-size: var(--text-sm);
    }
    
    #next-button {
        width: 100%;
        float: none;
        margin-top: var(--spacing-md);
    }
}

/* Responsive - Mobile */
@media (max-width: 480px) {
    :root {
        --spacing-lg: 1rem;
        --spacing-xl: 1.25rem;
        --text-lg: 1rem;
        --text-xl: 1.125rem;
    }
    
    body {
        padding: var(--spacing-xs);
        align-items: flex-start;
        padding-top: var(--spacing-md);
    }
    
    .start-screen,
    .score-container {
        padding: var(--spacing-lg);
    }
    
    .start-screen h1,
    .score-container h2 {
        font-size: var(--text-2xl);
        margin-bottom: var(--spacing-md);
    }
    
    .quiz-content {
        padding: var(--spacing-md);
    }
    
    .question {
        font-size: var(--text-base);
        margin-bottom: var(--spacing-md);
    }
    
    .options-container {
        grid-template-columns: 1fr;
    }
    
    .option-div {
        padding: var(--spacing-sm);
        font-size: var(--text-sm);
    }
    
    .timer-div {
        min-width: 100px;
        padding: var(--spacing-xs) var(--spacing-sm);
    }
    
    .timer-div svg {
        width: 16px;
        height: 16px;
    }
    
    #start-button,
    #restart {
        min-width: 160px;
        padding: var(--spacing-sm) var(--spacing-md);
        font-size: var(--text-base);
        width: 100%;
    }
    
    #user-score {
        font-size: var(--text-xl);
    }
}

/* Accessibility Improvements */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
    :root {
        --border-color: #000000;
        --text-dark: #000000;
        --text-light: #333333;
    }
    
    .option-div {
        border-width: 3px;
    }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        --card-bg: #2d3748;
        --text-dark: #f7fafc;
        --text-light: #e2e8f0;
        --border-color: #4a5568;
        --gradient-card: linear-gradient(135deg, #2d3748 0%, #1a202c 100%);
    }
    
    .option-div {
        background: #4a5568;
        color: #f7fafc;
    }
    
    .option-div:hover:not(:disabled) {
        background: #718096;
    }
    
    .header {
        background: linear-gradient(135deg, #4a5568 0%, #2d3748 100%);
    }
}