:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --error-color: #dc3545;
    --info-color: #17a2b8;
    --bg-color: #f8f9fa;
    --card-bg-color: #ffffff;
    --text-color: #343a40;
    --heading-color: #000;
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    box-sizing: border-box;
}

.app-container {
    background: var(--card-bg-color);
    border-radius: 15px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    max-width: 600px;
    width: 100%;
    padding: 40px;
    text-align: center;
    box-sizing: border-box;
    overflow: hidden;
}

.app-header {
    margin-bottom: 30px;
}

.header-title {
    color: var(--heading-color);
    font-size: 2.5em;
    margin: 0 0 10px;
    font-weight: 700;
}

.header-subtitle {
    font-size: 1.1em;
    color: var(--secondary-color);
}

.quiz-card, .result-card {
    background-color: #f1f1f1;
    padding: 30px;
    border-radius: 15px;
    border: 1px solid #ddd;
    transition: all 0.3s ease;
}

.quiz-card h2, .result-card h2 {
    margin-top: 0;
    color: var(--heading-color);
}

.form-container {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

input[type="text"] {
    width: 100%;
    padding: 12px;
    border-radius: 8px;
    border: 1px solid #ccc;
    box-sizing: border-box;
    font-size: 1em;
    transition: border-color 0.3s;
}

input[type="text"]:focus {
    outline: none;
    border-color: var(--primary-color);
}

button, .button {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: 8px;
    background-color: var(--primary-color);
    color: white;
    font-size: 1em;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
    text-decoration: none;
    display: block;
    text-align: center;
}

button:hover, .button:hover {
    background-color: #0056b3;
    transform: translateY(-2px);
}

button:disabled {
    background-color: #ccc;
    cursor: not-allowed;
}

.back-btn {
    background-color: var(--secondary-color);
}

.back-btn:hover {
    background-color: #5a6268;
}

.message {
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 20px;
    font-weight: 600;
}

.message.success {
    background-color: #d4edda;
    color: var(--success-color);
    border-color: #c3e6cb;
}

.message.error {
    background-color: #f8d7da;
    color: var(--error-color);
    border-color: #f5c6cb;
}

.message.info {
    background-color: #d1ecf1;
    color: var(--info-color);
    border-color: #bee5eb;
}

.hidden {
    display: none;
}

.question-container {
    margin-bottom: 20px;
    text-align: left;
}

.question-counter {
    font-size: 0.9em;
    color: var(--secondary-color);
    margin-bottom: 5px;
}

.question-text {
    font-size: 1.5em;
    margin: 0;
    line-height: 1.4;
}

.options {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.option {
    background-color: #f1f1f1;
    color: var(--text-color);
    border: 1px solid #ccc;
    text-align: left;
    padding: 15px;
    border-radius: 10px;
    transition: background-color 0.3s, border-color 0.3s, transform 0.2s;
}

.option:hover {
    background-color: #e9ecef;
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

.result-card h2 {
    color: var(--success-color);
}

.voucher-card {
    background-color: #e9f5e9;
    border: 2px dashed var(--success-color);
    padding: 20px;
    border-radius: 10px;
    margin-top: 20px;
}

.voucher-card h3 {
    margin-top: 0;
    color: var(--success-color);
}

.voucher-code {
    font-size: 1.5em;
    font-weight: 700;
    color: var(--heading-color);
    margin: 10px 0;
    word-break: break-all;
}

.copy-btn {
    background-color: var(--info-color);
    color: white;
    margin-top: 15px;
}

.copy-btn:hover {
    background-color: #117a8b;
}

.app-footer {
    margin-top: 30px;
    color: var(--secondary-color);
    font-size: 0.9em;
}

.logout-form {
    margin-top: 20px;
}

.logout-btn {
    background-color: var(--error-color);
}

.logout-btn:hover {
    background-color: #bd2130;
}

@media (max-width: 600px) {
    .app-container {
        padding: 20px;
    }
    .header-title {
        font-size: 2em;
    }
}