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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f7fa;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding-bottom: 15px;
    border-bottom: 1px solid #ddd;
}

h1 {
    color: #2c3e50;
}

h2 {
    margin-bottom: 20px;
    color: #2c3e50;
}

.hidden {
    display: none;
}

/* Welcome Screen */
#welcome-screen {
    text-align: center;
    padding: 40px 0;
}

.exam-selection {
    margin-top: 30px;
    display: flex;
    justify-content: center;
    gap: 20px;
}

/* Buttons */
.btn {
    padding: 12px 24px;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

.btn:hover {
    background-color: #2980b9;
}

.nav-btn {
    padding: 8px 16px;
    background-color: #ecf0f1;
    color: #333;
    border: 1px solid #ddd;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.nav-btn:hover:not(:disabled) {
    background-color: #ddd;
}

.nav-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Exam Screen */
#progress-bar {
    height: 8px;
    background-color: #ecf0f1;
    border-radius: 4px;
    margin-bottom: 20px;
    overflow: hidden;
}

#progress {
    height: 100%;
    background-color: #2ecc71;
    width: 0%;
    transition: width 0.3s;
}

#question-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

#question-container {
    background-color: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
}

#options-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.option {
    padding: 15px;
    background-color: #f8f9fa;
    border: 1px solid #ddd;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s;
}

.option:hover {
    background-color: #e9ecef;
}

.option.selected {
    background-color: #d4edff;
    border-color: #3498db;
}

#question-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 30px;
}

.question-number {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #ecf0f1;
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s;
}

.question-number.answered {
    background-color: #3498db;
    color: white;
}

.question-number.current {
    border: 2px solid #2c3e50;
}

#submit-exam {
    display: block;
    margin: 0 auto;
}

/* Timer */
#timer {
    font-size: 18px;
    font-weight: bold;
    color: #2c3e50;
}

/* Results Screen */
#score-summary {
    background-color: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
    text-align: center;
}

#score {
    font-size: 24px;
    margin-bottom: 10px;
}

#pass-fail {
    font-size: 20px;
    font-weight: bold;
}

.pass {
    color: #2ecc71;
}

.fail {
    color: #e74c3c;
}

#review-container {
    background-color: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
}

.review-question {
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 1px solid #ddd;
}

.review-question h4 {
    margin-bottom: 15px;
}

.review-options {
    margin-bottom: 15px;
}

.review-option {
    padding: 10px;
    margin-bottom: 8px;
    border-radius: 4px;
}

.correct {
    background-color: rgba(46, 204, 113, 0.2);
}

.incorrect {
    background-color: rgba(231, 76, 60, 0.2);
}

.explanation {
    background-color: #f8f9fa;
    padding: 15px;
    border-left: 4px solid #3498db;
    margin-top: 15px;
}

#restart-btn {
    display: block;
    margin: 0 auto;
}