body {
    font-family: 'Poppins', sans-serif;
    background-color: #f4f4f9;
    margin: 0;
    padding: 20px;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: #fff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

header {
    text-align: center;
    margin-bottom: 20px;
}

h1 {
    color: #2c3e50;
    margin-bottom: 10px;
    font-size: 2rem;
}

h2 {
    color: #2c3e50;
    font-size: 1.75rem;
    margin-top: 20px;
}

h3 {
    color: #34495e;
    font-size: 1.25rem;
    margin-bottom: 10px;
}

h4 {
    color: #34495e;
    font-size: 1.1rem;
    margin-bottom: 8px;
}

p {
    margin-bottom: 15px;
}

.input-group {
    margin-bottom: 20px;
}

.input-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 8px;
    color: #34495e;
}

.input-group label.required-field::after {
    content: '*';
    color: #e74c3c;
    margin-left: 5px;
}

.input-group input,
.input-group select {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 16px;
    box-sizing: border-box;
    transition: border-color 0.3s, box-shadow 0.3s;
}

.input-group input:focus,
.input-group select:focus {
    border-color: #3498db;
    outline: none;
    box-shadow: 0 0 5px rgba(52, 152, 219, 0.3);
}

.input-group small {
    display: block;
    color: #7f8c8d;
    font-size: 12px;
    margin-top: 5px;
}

.btn {
    display: block;
    width: 100%;
    padding: 14px;
    background: #3498db;
    color: #fff;
    border: none;
    border-radius: 5px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    text-align: center;
    text-decoration: none;
    transition: background 0.3s, transform 0.2s;
    touch-action: manipulation;
}

.btn:hover {
    background: #2980b9;
    transform: translateY(-2px);
}

.btn:active {
    transform: translateY(0);
}

.hidden {
    display: none;
}

.prediction-result {
    margin-top: 20px;
    padding: 20px;
    background: #f9f9f9;
    border-radius: 5px;
    border: 1px solid #eee;
}

.section {
    margin-bottom: 20px;
}

.flex-container {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    justify-content: space-between;
}

.flex-item {
    flex: 1 1 45%;
    min-width: 200px;
    margin-bottom: 15px;
}

.text-center {
    text-align: center;
}

.progress-bar {
    background: #f0f0f0;
    height: 30px;
    border-radius: 15px;
    margin-bottom: 10px;
    overflow: hidden;
}

.progress {
    background: linear-gradient(to right, #ff6b6b, #ff8e8e);
    height: 100%;
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
}

.number-circle {
    font-size: 24px;
    font-weight: bold;
    border-radius: 50%;
    width: 50