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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f4f7f6;
    min-height: 100vh;
    color: #2c3e50;
    line-height: 1.6;
    user-select: none;
}

.screen {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: linear-gradient(135deg, #3498db10 0%, #2ecc7110 100%);
}

.hidden {
    display: none !important;
}

#banned-screen {
    background: linear-gradient(to right, #e74c3c, #c0392b);
    color: white;
    text-align: center;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

#banned-screen h1 {
    font-size: 4rem;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
    font-weight: 700;
}

#test-container {
    background: white;
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
    max-width: 700px;
    width: 100%;
    border-top: 8px solid #3498db;
}

#test-header {
    text-align: center;
    margin-bottom: 30px;
    position: relative;
}

#test-header::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 100px;
    height: 4px;
    background-color: #3498db;
}

#test-header h1 {
    color: #2c3e50;
    margin-bottom: 10px;
    font-weight: 600;
    letter-spacing: -0.5px;
}

#question-counter {
    font-size: 1rem;
    color: #7f8c8d;
    margin-bottom: 15px;
}

#warning {
    background-color: #f39c12;
    color: white;
    padding: 12px;
    border-radius: 6px;
    border: 1px solid #d35400;
    font-weight: 600;
    text-align: center;
}

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

#question {
    font-size: 1.4rem;
    color: #2c3e50;
    margin-bottom: 20px;
    text-align: center;
    padding: 25px;
    background-color: #f1f4f7;
    border-radius: 10px;
    border-left: 6px solid #3498db;
    font-weight: 500;
}

#answer-input {
    display: flex;
    gap: 15px;
    align-items: center;
    justify-content: center;
}

#answer {
    padding: 15px;
    font-size: 1.2rem;
    border: 2px solid #bdc3c7;
    border-radius: 8px;
    width: 200px;
    text-align: center;
    transition: all 0.3s ease;
}

#answer:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

button {
    padding: 15px 30px;
    font-size: 1rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

#next-btn {
    background-color: #2ecc71;
    color: white;
}

#next-btn:disabled {
    background-color: #95a5a6;
    cursor: not-allowed;
}

#next-btn:not(:disabled):hover {
    background-color: #27ae60;
}

#submit-btn {
    background-color: #e74c3c;
    color: white;
    font-size: 1.2rem;
}

#submit-btn:hover {
    background-color: #c0392b;
}

#submit-container {
    text-align: center;
}

#results-screen {
    background: linear-gradient(135deg, #3498db10 0%, #2ecc7110 100%);
}

#results-screen > div {
    background: white;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
    max-width: 900px;
    width: 100%;
    text-align: center;
    border-top: 8px solid #3498db;
}

#score {
    font-size: 2rem;
    margin-bottom: 30px;
    color: #2c3e50;
    font-weight: 600;
}

#question-results {
    text-align: left;
    margin-bottom: 30px;
    max-height: 400px;
    overflow-y: auto;
}

.question-result {
    padding: 15px;
    margin: 10px 0;
    border-radius: 8px;
    border-left: 6px solid;
    background-color: #f9f9f9;
    transition: all 0.3s ease;
}

.correct {
    background-color: #d4edda;
    border-color: #28a745;
}

.incorrect {
    background-color: #f8d7da;
    border-color: #dc3545;
}

#restart-btn {
    background-color: #3498db;
    color: white;
    font-size: 1.1rem;
}

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

#multiple-choice-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
    margin-top: 20px;
}

.multiple-choice-option {
    background-color: #f1f4f7;
    border: 2px solid #bdc3c7;
    padding: 15px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    border-radius: 8px;
}

.multiple-choice-option:hover {
    background-color: #e9ecef;
    border-color: #3498db;
}

.multiple-choice-option.selected {
    background-color: #3498db;
    color: white;
    border-color: #2980b9;
}

/* Grade Selection Styles */
#grade-selection-container {
    background: white;
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
    max-width: 800px;
    width: 100%;
    text-align: center;
    border-top: 8px solid #3498db;
}

#grade-selection-container h1 {
    color: #2c3e50;
    margin-bottom: 30px;
    font-weight: 600;
}

#grade-buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
}

.grade-btn {
    background-color: #f1f4f7;
    border: 2px solid #bdc3c7;
    padding: 15px;
    border-radius: 8px;
    font-weight: 600;
    transition: all 0.3s ease;
    cursor: pointer;
}

.grade-btn:hover {
    background-color: #3498db;
    color: white;
    border-color: #2980b9;
}