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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    background-color: #f0f2f5;
    color: #333;
}

.container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 2rem;
    background-color: white;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.screen {
    text-align: center;
}

.hidden {
    display: none;
}

h1 {
    color: #2c3e50;
    margin-bottom: 2rem;
}

.input-group {
    margin: 2rem 0;
}

input[type="text"] {
    padding: 0.8rem;
    font-size: 1rem;
    border: 2px solid #ddd;
    border-radius: 5px;
    margin-right: 1rem;
    width: 300px;
}

button {
    padding: 0.8rem 1.5rem;
    font-size: 1rem;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #2980b9;
}

.progress-bar {
    width: 100%;
    height: 20px;
    background-color: #eee;
    border-radius: 10px;
    margin: 1rem 0;
    overflow: hidden;
}

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

#question-container {
    margin: 2rem 0;
    text-align: left;
}

.option {
    padding: 1rem;
    margin: 1rem 0;
    background-color: #f8f9fa;
    border: 2px solid #ddd;
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s;
}

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

.option.selected {
    background-color: #e3f2fd;
    border-color: #2196f3;
}

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

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

.button-group {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-top: 2rem;
}

#certificate-canvas {
    display: none;
}

@media (max-width: 600px) {
    .container {
        margin: 1rem;
        padding: 1rem;
    }

    input[type="text"] {
        width: 100%;
        margin-bottom: 1rem;
    }

    .button-group {
        flex-direction: column;
    }
}