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

body {
    font-family: 'Arial', sans-serif;
    background-color: #000;
    color: #fff;
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.section {
    background-color: #111;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(255, 255, 255, 0.1);
}

.hidden {
    display: none;
}

h1, h2 {
    text-align: center;
    margin-bottom: 2rem;
    color: #4CAF50;
}

input {
    width: 100%;
    padding: 0.8rem;
    margin-bottom: 1rem;
    border: none;
    border-radius: 5px;
    background-color: #222;
    color: #fff;
}

button {
    width: 100%;
    padding: 1rem;
    border: none;
    border-radius: 5px;
    background-color: #4CAF50;
    color: white;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #45a049;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.category-card {
    background-color: #222;
    padding: 1rem;
    border-radius: 5px;
    cursor: pointer;
    transition: transform 0.3s;
    text-align: center;
}

.category-card:hover {
    transform: translateY(-5px);
    background-color: #333;
}

.option {
    background-color: #222;
    padding: 1rem;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.option:hover {
    background-color: #333;
}

.option.selected {
    background-color: #4CAF50;
}

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

#question-text {
    font-size: 1.2rem;
    margin-bottom: 2rem;
}

#timer {
    font-size: 1.2rem;
    color: #4CAF50;
}

#score {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 2rem;
}

.button-group {
    display: flex;
    gap: 2rem;
    justify-content: center;
    width: 100%;
    padding: 0.5rem;
    margin-top: 0.5rem;
}

.button-group button {
    flex: 1;
    max-width: 45%;
}

.secondary-btn {
    background: #333;
    color: #fff;
    border: 1px solid #4CAF50;
}

.secondary-btn:hover {
    background: #4CAF50;
}

.auth-form {
    max-width: 400px;
    margin: 2rem auto;
    padding: 2rem;
    border: 1px solid #ccc;
    border-radius: 8px;
    background: white;
}

.form-group {
    margin-bottom: 1rem;
}

.form-group input {
    width: 100%;
    padding: 0.5rem;
    border: 1px solid #ccc;
    border-radius: 4px;
}

.form-group button {
    width: 100%;
    padding: 0.5rem;
    background: #007bff;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

.form-group button:hover {
    background: #0056b3;
}