:root {
    --primary-color: #4CAF50; /* Màu xanh lá cây */
    --secondary-color: #f4f4f4;
    --text-color: #333;
    --border-color: #ccc;
    --box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Roboto', sans-serif;
    color: var(--text-color);
    line-height: 1.6;
    background-color: var(--secondary-color);
}

.header {
    height: 60px;
    background-color: var(--primary-color);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    box-shadow: var(--box-shadow);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
}

.logo {
    height: 40px;
    margin-right: 15px;
}

.header-title {
    font-size: 1.5em;
    font-weight: bold;
}

.main-content {
    max-width: 900px;
    margin: 20px auto;
    padding: 20px;
    background-color: white;
    border-radius: 8px;
    box-shadow: var(--box-shadow);
}

.info-section {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    justify-content: space-between;
    margin-bottom: 20px;
}

.input-group {
    display: flex;
    flex-direction: column;
    flex: 1 1 250px;
}

.input-group label {
    font-weight: bold;
    margin-bottom: 5px;
}

.input-group input {
    padding: 8px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    width: 100%;
}

.coach-selection {
    margin-bottom: 20px;
}

.coach-selection select {
    padding: 8px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    width: 100%;
    max-width: 300px;
}

.stage-title {
    font-size: 1.3em;
    font-weight: bold;
    color: var(--primary-color);
    margin-top: 25px;
    margin-bottom: 15px;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 5px;
}

.question-item {
    margin-bottom: 15px;
    border-bottom: 1px dashed var(--border-color);
    padding-bottom: 10px;
}

.question-text {
    font-weight: bold;
}

.rating-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 10px;
    font-size: 0.9em;
}

.rating-table th, .rating-table td {
    padding: 8px;
    text-align: center;
    border: 1px solid #ddd;
}

.rating-table th {
    background-color: #f2f2f2;
}

.rating-table input[type="radio"] {
    margin: 0 3px;
    cursor: pointer;
}

.calculate-button {
    display: block;
    width: 100%;
    padding: 12px;
    font-size: 1.1em;
    color: white;
    background-color: var(--primary-color);
    border: none;
    border-radius: 4px;
    cursor: pointer;
    margin-top: 30px;
    transition: background-color 0.3s;
}

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

.result-container {
    margin-top: 20px;
    padding: 20px;
    background-color: #e8f5e9;
    border: 1px solid var(--primary-color);
    border-radius: 8px;
}

.result-container h2 {
    font-size: 1.5em;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.result-container p {
    margin-bottom: 10px;
}

.footer {
    text-align: center;
    padding: 15px;
    font-size: 0.9em;
    color: #777;
    margin-top: 20px;
}

/* Responsive design */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        text-align: center;
    }

    .logo {
        margin-right: 0;
        margin-bottom: 5px;
    }

    .header-title {
        font-size: 1.2em;
    }

    .info-section {
        flex-direction: column;
        gap: 10px;
    }

    .input-group {
        width: 100%;
    }
}