/* ===== Global Variables ===== */
:root {
    /* Colors */
    --primary-color: #0559CF;
    --primary-dark: #0447a7;
    --primary-light: #e6f0ff;
    --secondary-color: #FF6B00;
    --secondary-dark: #e05e00;
    --secondary-light: #fff0e6;
    --success-color: #28a745;
    --success-light: #e6f7e9;
    --danger-color: #dc3545;
    --danger-light: #f8e7e9;
    --white: #ffffff;
    --black: #000000;
    --text-color: #333333;
    --text-light: #666666;
    --light-bg: #f8f9fa;
    --border-color: #e0e0e0;
    
    /* Shadows */
    --shadow-light: 0 2px 10px rgba(0, 0, 0, 0.05);
    --shadow-medium: 0 5px 15px rgba(0, 0, 0, 0.1);
    --shadow-dark: 0 8px 30px rgba(0, 0, 0, 0.15);
    
    /* Borders */
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 12px;
    
    /* Spacing */
    --spacing-xs: 5px;
    --spacing-sm: 10px;
    --spacing-md: 20px;
    --spacing-lg: 30px;
    --spacing-xl: 40px;
    
    /* Transitions */
    --transition-fast: 0.3s ease;
    --transition-medium: 0.5s ease;
    --transition-slow: 0.8s ease;
}

/* ===== Reset & Base Styles ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--light-bg);
    color: var(--text-color);
    line-height: 1.6;
}

a {
    text-decoration: none;
    color: var(--text-color);
    transition: var(--transition-fast);
}

a:hover {
    color: var(--primary-color);
}

/* ===== Quiz Container ===== */
.quiz-container {
    max-width: 900px;
    margin: 0 auto;
    padding: var(--spacing-md);
    position: relative;
}

/* ===== Quiz Header ===== */
.quiz-header {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: var(--white);
    padding: var(--spacing-xl) 0;
    margin-top: 80px;
    margin-bottom: var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-medium);
    position: relative;
    overflow: hidden;
}

.quiz-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('../Assets/Images/pattern.svg') repeat;
    opacity: 0.1;
}

.quiz-header-content {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    position: relative;
    z-index: 1;
    text-align: center;
}

.quiz-header h1 {
    font-size: 2.8rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.quiz-header p {
    font-size: 1.2rem;
    margin-bottom: var(--spacing-lg);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.quiz-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-lg);
}

.stat {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    background-color: rgba(255, 255, 255, 0.15);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius-md);
    backdrop-filter: blur(5px);
}

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

/* ===== Main Title ===== */
.quiz-container h1 {
    text-align: center;
    margin: var(--spacing-xl) 0 var(--spacing-lg);
    color: var(--primary-color);
    font-size: 2.5rem;
    font-weight: 700;
    position: relative;
    padding-bottom: var(--spacing-md);
}

.quiz-container h1::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

/* ===== Section Indicator ===== */
.section-indicator {
    background: linear-gradient(to right, var(--primary-color), var(--primary-dark));
    color: var(--white);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius-md);
    text-align: center;
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-medium);
    position: sticky;
    top: 10px;
    z-index: 100;
    font-weight: 600;
    transition: var(--transition-fast);
    backdrop-filter: blur(5px);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

/* ===== Quiz Sections ===== */
.quiz-section {
    background-color: var(--white);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-medium);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
    transition: var(--transition-medium);
    border: 1px solid var(--border-color);
    position: relative;
}

.quiz-section:hover {
    box-shadow: var(--shadow-dark);
    transform: translateY(-5px);
}

.section-title {
    color: var(--primary-color);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--primary-light);
    font-size: 1.5rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.section-title::before {
    content: '';
    display: inline-block;
    width: 8px;
    height: 24px;
    background-color: var(--primary-color);
    border-radius: 4px;
}

/* ===== Questions ===== */
.question {
    background-color: var(--light-bg);
    border-radius: var(--border-radius-md);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-light);
    border-left: 4px solid var(--primary-color);
    transition: var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.question::after {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, transparent 50%, rgba(5, 89, 207, 0.1) 50%);
}

.question:hover {
    box-shadow: var(--shadow-medium);
    transform: translateY(-3px);
}

.question p {
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-color);
    font-size: 1.1rem;
    position: relative;
    padding-left: var(--spacing-md);
}

.question p::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 8px;
    height: 8px;
    background-color: var(--primary-color);
    border-radius: 50%;
}

/* ===== Code Blocks ===== */
.code-block {
    background-color: #2d2d2d;
    color: #f8f8f2;
    padding: var(--spacing-md);
    border-radius: var(--border-radius-sm);
    overflow-x: auto;
    margin-bottom: var(--spacing-md);
    font-family: 'Courier New', Courier, monospace;
    line-height: 1.5;
    font-size: 0.9rem;
    border: 1px solid #444;
    position: relative;
}

.code-block::before {
    content: 'C++';
    position: absolute;
    top: 0;
    right: 0;
    background-color: #444;
    color: #f8f8f2;
    padding: 2px 8px;
    font-size: 0.8rem;
    border-bottom-left-radius: var(--border-radius-sm);
}

/* Syntax Highlighting for Code Blocks */
.code-block .keyword {
    color: #ff79c6;
}

.code-block .function {
    color: #50fa7b;
}

.code-block .string {
    color: #f1fa8c;
}

.code-block .comment {
    color: #6272a4;
    font-style: italic;
}

.code-block .number {
    color: #bd93f9;
}

/* ===== Options ===== */
.options {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.options label {
    display: flex;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: var(--white);
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: var(--transition-fast);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.options label:hover {
    background-color: var(--primary-light);
    border-color: var(--primary-color);
    transform: translateX(5px);
}

.options input[type="radio"] {
    margin-right: var(--spacing-md);
    accent-color: var(--primary-color);
    width: 18px;
    height: 18px;
    position: relative;
    z-index: 1;
}

/* Selected Option Styling */
.options input[type="radio"]:checked + span {
    font-weight: 600;
    color: var(--primary-color);
}

.options label.selected {
    background-color: var(--primary-light);
    border-color: var(--primary-color);
    position: relative;
}

.options label.selected::after {
    content: '✓';
    position: absolute;
    right: 15px;
    color: var(--primary-color);
    font-weight: bold;
}

/* Correct and Incorrect Answer Styling */
.options label.correct {
    background-color: var(--success-light);
    border-color: var(--success-color);
    animation: pulse-success 1s;
}

.options label.incorrect {
    background-color: var(--danger-light);
    border-color: var(--danger-color);
    animation: pulse-danger 1s;
}

@keyframes pulse-success {
    0% { box-shadow: 0 0 0 0 rgba(40, 167, 69, 0.7); }
    70% { box-shadow: 0 0 0 10px rgba(40, 167, 69, 0); }
    100% { box-shadow: 0 0 0 0 rgba(40, 167, 69, 0); }
}

@keyframes pulse-danger {
    0% { box-shadow: 0 0 0 0 rgba(220, 53, 69, 0.7); }
    70% { box-shadow: 0 0 0 10px rgba(220, 53, 69, 0); }
    100% { box-shadow: 0 0 0 0 rgba(220, 53, 69, 0); }
}

/* ===== Navigation Buttons ===== */
.navigation-buttons {
    display: flex;
    justify-content: space-between;
    margin-top: var(--spacing-xl);
    gap: var(--spacing-md);
}

.navigation-buttons button {
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--border-radius-md);
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    border: none;
    position: relative;
    overflow: hidden;
}

.navigation-buttons button::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: var(--transition-fast);
}

.navigation-buttons button:hover::before {
    left: 100%;
}

.prev-btn, .next-btn {
    background-color: var(--primary-light);
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

.prev-btn:hover, .next-btn:hover {
    background-color: var(--primary-color);
    color: var(--white);
    transform: translateY(-3px);
    box-shadow: var(--shadow-medium);
}

.check-btn {
    background: linear-gradient(to right, var(--primary-color), var(--primary-dark));
    color: var(--white);
}

.check-btn:hover {
    background: linear-gradient(to right, var(--primary-dark), var(--primary-color));
    transform: translateY(-3px);
    box-shadow: var(--shadow-medium);
}

.finish-btn {
    background-color: var(--success-light);
    color: var(--success-color);
    border: 1px solid var(--success-color);
    position: relative;
    overflow: hidden;
}

.finish-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(40, 167, 69, 0.1), transparent);
    transition: var(--transition-fast);
}

.finish-btn:hover::before {
    left: 100%;
}

.finish-btn:hover {
    background-color: var(--success-color);
    color: var(--white);
    transform: translateY(-3px);
    box-shadow: var(--shadow-medium);
}

/* Button Disabled State */
.navigation-buttons button:disabled {
    background-color: var(--border-color);
    color: var(--text-light);
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
    opacity: 0.7;
}

/* ===== Results ===== */
.result, .incorrect {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    border-radius: var(--border-radius-md);
    animation: fadeIn 0.5s ease;
}

.result {
    background-color: var(--success-light);
    border: 1px solid var(--success-color);
    position: relative;
    overflow: hidden;
}

.result::after {
    content: '✓';
    position: absolute;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 2rem;
    color: rgba(40, 167, 69, 0.2);
}

.result h3 {
    color: var(--success-color);
    margin-bottom: var(--spacing-sm);
}

.incorrect {
    background-color: var(--danger-light);
    border: 1px solid var(--danger-color);
    position: relative;
    overflow: hidden;
}

.incorrect::after {
    content: '!';
    position: absolute;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 2rem;
    color: rgba(220, 53, 69, 0.2);
}

.incorrect h3 {
    color: var(--danger-color);
    margin-bottom: var(--spacing-sm);
}

/* ===== Feedback ===== */
.feedback {
    margin-top: var(--spacing-sm);
    padding: var(--spacing-sm);
    border-radius: var(--border-radius-sm);
    font-size: 0.9rem;
    display: none;
}

.feedback.correct {
    background-color: var(--success-light);
    color: var(--success-color);
    border-left: 3px solid var(--success-color);
    display: block;
}

.feedback.incorrect {
    background-color: var(--danger-light);
    color: var(--danger-color);
    border-left: 3px solid var(--danger-color);
    display: block;
}

.feedback.unanswered {
    background-color: var(--light-bg);
    color: var(--text-light);
    border-left: 3px solid var(--text-light);
    display: block;
}

.feedback i {
    margin-right: var(--spacing-xs);
}

/* Results Summary */
.results-summary {
    margin-top: var(--spacing-xl);
    padding: var(--spacing-lg);
    background-color: var(--white);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-medium);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.results-summary::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
}

.results-summary h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
    font-size: 1.8rem;
}

.score-container {
    display: flex;
    justify-content: center;
    margin: var(--spacing-lg) 0;
}

.score-circle {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    background: conic-gradient(var(--primary-color) 0%, var(--secondary-color) 100%);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: var(--white);
    position: relative;
    box-shadow: var(--shadow-medium);
}

.score-circle::before {
    content: '';
    position: absolute;
    width: 130px;
    height: 130px;
    border-radius: 50%;
    background-color: var(--white);
}

.score-circle span {
    position: relative;
    z-index: 1;
    color: var(--text-color);
}

#scorePercent {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary-color);
}

.score-percent {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

.stats-container {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
    flex-wrap: wrap;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius-md);
    background-color: var(--light-bg);
    box-shadow: var(--shadow-light);
}

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

.incorrect-icon {
    color: var(--danger-color);
}

.unanswered-icon {
    color: var(--text-light);
}

/* Chart Container */
.chart-container {
    margin: var(--spacing-lg) 0;
    height: 300px;
    position: relative;
}

/* Results Message */
.results-message {
    padding: var(--spacing-md);
    border-radius: var(--border-radius-md);
    margin: var(--spacing-lg) 0;
    text-align: center;
}

.results-message.excellent {
    background-color: var(--success-light);
    border: 1px solid var(--success-color);
}

.results-message.good {
    background-color: var(--primary-light);
    border: 1px solid var(--primary-color);
}

.results-message.average {
    background-color: var(--secondary-light);
    border: 1px solid var(--secondary-color);
}

.results-message.poor {
    background-color: var(--danger-light);
    border: 1px solid var(--danger-color);
}

.results-message h3 {
    margin-bottom: var(--spacing-sm);
    font-size: 1.5rem;
}

/* Results Buttons */
.results-buttons {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
    flex-wrap: wrap;
}

.results-buttons button {
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--border-radius-md);
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    border: none;
}

.retry-btn {
    background-color: var(--primary-light);
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

.retry-btn:hover {
    background-color: var(--primary-color);
    color: var(--white);
    transform: translateY(-3px);
    box-shadow: var(--shadow-medium);
}

.courses-btn {
    background-color: var(--secondary-light);
    color: var(--secondary-color);
    border: 1px solid var(--secondary-color);
}

.courses-btn:hover {
    background-color: var(--secondary-color);
    color: var(--white);
    transform: translateY(-3px);
    box-shadow: var(--shadow-medium);
}

.certificate-btn {
    background-color: var(--success-light);
    color: var(--success-color);
    border: 1px solid var(--success-color);
    position: relative;
    overflow: hidden;
}

.certificate-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(40, 167, 69, 0.1), transparent);
    transition: var(--transition-fast);
}

.certificate-btn:hover::before {
    left: 100%;
}

.certificate-btn:hover {
    background-color: var(--success-color);
    color: var(--white);
    transform: translateY(-3px);
    box-shadow: var(--shadow-medium);
}

/* ===== Timer ===== */
.timer {
    position: fixed;
    top: 100px; 
    right: 20px;
    background-color: var(--white);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius-md);
    box-shadow: var(--shadow-medium);
    display: flex;
    align-items: center;
    gap: 8px;
    z-index: 1000; 
    border: 1px solid var(--border-color);
    animation: fadeIn 0.5s ease;
    transform: scale(1.1); 
}

.timer i {
    color: var(--primary-color);
    font-size: 1.2rem; 
}

#timeLeft {
    font-weight: 700;
    color: var(--text-color);
    font-family: 'Courier New', Courier, monospace;
    font-size: 1.1rem;
}

/* Timer Warning State */
.timer.warning {
    background-color: var(--secondary-light);
    border-color: var(--secondary-color);
    animation: pulse 1s infinite;
}

.timer.warning #timeLeft {
    color: var(--secondary-color);
}

/* ===== Progress Bar ===== */
.progress-container {
    width: 100%;
    background-color: var(--light-bg);
    border-radius: 5px;
    margin: var(--spacing-md) 0;
    height: 8px;
    overflow: hidden;
    box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.1);
}

.progress-bar {
    height: 100%;
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    border-radius: 5px;
    transition: width 0.5s ease;
    position: relative;
    overflow: hidden;
}

.progress-bar::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        45deg,
        rgba(255, 255, 255, 0.2) 25%,
        transparent 25%,
        transparent 50%,
        rgba(255, 255, 255, 0.2) 50%,
        rgba(255, 255, 255, 0.2) 75%,
        transparent 75%,
        transparent
    );
    background-size: 20px 20px;
    animation: progress-animation 1s linear infinite;
}

@keyframes progress-animation {
    0% { background-position: 0 0; }
    100% { background-position: 20px 0; }
}

/* ===== Quiz Instructions ===== */
.quiz-instructions {
    background-color: var(--primary-light);
    border-radius: var(--border-radius-md);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    border-left: 4px solid var(--primary-color);
    position: relative;
}

.quiz-instructions::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 0 20px 20px 0;
    border-color: transparent var(--primary-color) transparent transparent;
}

.quiz-instructions h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: 8px;
}

.quiz-instructions h3 i {
    color: var(--primary-color);
}

.quiz-instructions ul {
    list-style-type: none;
    margin-left: var(--spacing-md);
}

.quiz-instructions li {
    margin-bottom: var(--spacing-xs);
    position: relative;
    padding-left: var(--spacing-md);
}

.quiz-instructions li::before {
    content: '✓';
    color: var(--primary-color);
    position: absolute;
    left: 0;
}

/* ===== Hint System ===== */
.hint-container {
    margin-top: var(--spacing-md);
}

.hint-button {
    background-color: transparent;
    color: var(--primary-color);
    border: 1px dashed var(--primary-color);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    font-size: 0.9rem;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 5px;
}

.hint-button:hover {
    background-color: var(--primary-light);
    transform: translateY(-2px);
}

.hint-button i {
    color: var(--secondary-color);
}

.hint-content {
    margin-top: var(--spacing-sm);
    padding: var(--spacing-sm);
    background-color: var(--primary-light);
    border-radius: var(--border-radius-sm);
    font-size: 0.9rem;
    color: var(--text-color);
    display: none;
    border-left: 3px solid var(--primary-color);
    position: relative;
}

.hint-content::before {
    content: '💡';
    position: absolute;
    left: -15px;
    top: 50%;
    transform: translateY(-50%);
    background-color: var(--white);
    width: 25px;
    height: 25px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
    border: 1px solid var(--primary-color);
}

/* ===== Back to Top Button ===== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: var(--shadow-medium);
    transition: var(--transition-fast);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    border: 2px solid var(--white);
}

.back-to-top:hover {
    background: linear-gradient(to right, var(--primary-color), var(--primary-dark));
    color: var(--white);
    transform: translateY(-5px);
    box-shadow: var(--shadow-medium);
}

/* ===== Confetti Animation ===== */
#confettiContainer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9999;
    overflow: hidden;
}

.confetti {
    position: absolute;
    width: 10px;
    height: 10px;
    background-color: var(--primary-color);
    top: -10px;
    animation: confetti-fall 5s linear forwards;
    opacity: 0.8;
}

@keyframes confetti-fall {
    0% {
        transform: translateY(0) rotate(0deg);
        opacity: 0.8;
    }
    100% {
        transform: translateY(100vh) rotate(720deg);
        opacity: 0;
    }
}

/* ===== Preloader ===== */
.preloader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--white);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

.spinner {
    width: 60px;
    height: 60px;
    border: 5px solid var(--primary-light);
    border-top: 5px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* ===== Back to Top Button ===== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: var(--shadow-medium);
    transition: var(--transition-fast);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
    animation: bounce 2s infinite;
}

.back-to-top:hover {
    background: linear-gradient(to right, var(--primary-color), var(--primary-dark));
    color: var(--white);
    transform: translateY(-5px);
    box-shadow: var(--shadow-medium);
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-10px); }
    60% { transform: translateY(-5px); }
}

/* ===== Media Queries ===== */
@media (max-width: 992px) {
    .quiz-header h1 {
        font-size: 2.2rem;
    }
    
    .quiz-stats {
        flex-wrap: wrap;
        gap: var(--spacing-md);
    }
    
    .navigation-buttons {
        flex-direction: column;
    }
    
    .results-buttons {
        flex-direction: column;
    }
    
    .timer {
        top: auto;
        bottom: 20px;
        right: 20px;
    }
}

@media (max-width: 768px) {
    .quiz-container {
        padding: var(--spacing-sm);
    }
    
    .quiz-section {
        padding: var(--spacing-md);
    }
    
    .quiz-header h1 {
        font-size: 1.8rem;
    }
    
    .quiz-header p {
        font-size: 1rem;
    }
    
    .stats-container {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .score-circle {
        width: 120px;
        height: 120px;
    }
    
    .score-circle::before {
        width: 100px;
        height: 100px;
    }
    
    #scorePercent {
        font-size: 2.5rem;
    }
    
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
    }
}

@media (max-width: 576px) {
    .quiz-header h1 {
        font-size: 1.5rem;
    }
    
    .section-title {
        font-size: 1.2rem;
    }
    
    .question p {
        font-size: 1rem;
    }
    
    .options label {
        padding: var(--spacing-xs) var(--spacing-sm);
    }
    
    .navigation-buttons button {
        padding: var(--spacing-xs) var(--spacing-md);
        font-size: 0.9rem;
    }
    
    .results-buttons button {
        padding: var(--spacing-xs) var(--spacing-md);
        font-size: 0.9rem;
    }
    
    .chart-container {
        height: 200px;
    }
}

/* ===== Animations ===== */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

/* ===== Print Styles for Certificate ===== */
@media print {
    body * {
        visibility: hidden;
    }
    
    #certificateContainer, #certificateContainer * {
        visibility: visible;
    }
    
    #certificateContainer {
        position: absolute;
        left: 0;
        top: 0;
        width: 100%;
        height: 100%;
    }
}