body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: #f4f7f6;
    color: #333;
    margin: 0;
    padding: 20px;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: #fff;
    padding: 20px 40px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

h1, h2 {
    color: #0056b3;
}

h1 {
    text-align: center;
    margin-bottom: 20px;
}

p {
    line-height: 1.6;
}

.file-input {
    display: block;
    width: 100%;
    padding: 10px;
    margin: 20px 0;
    border: 2px dashed #ccc;
    border-radius: 4px;
    text-align: center;
    cursor: pointer;
}

.btn {
    display: inline-block;
    background-color: #007bff;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    text-decoration: none;
    font-size: 16px;
    margin-top: 10px;
}

.btn:hover {
    background-color: #0056b3;
}

.error {
    color: #d9534f;
    background-color: #f2dede;
    border: 1px solid #ebccd1;
    padding: 10px;
    border-radius: 4px;
    margin-top: 20px;
}

table.data {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

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

table.data th {
    background-color: #f2f2f2;
    color: #333;
}

.chart-container {
    margin-top: 30px;
    margin-bottom: 30px;
}