body {
    font-family: Arial, sans-serif;
    margin: 20px;
    background: #f5f5f5;
}

h1 {
    text-align: center;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: white;
}

th {
    background: #007BFF;
    color: white;
}

th,
td {
    border: 1px solid #ccc;
    padding: 10px;
    text-align: left;
    vertical-align: top;
}

tr:nth-child(even) {
    background: #f9f9f9;
}

.demo {
    width: 120px;
    min-height: 40px;
    background: #d9e8ff;
    border: 1px solid #999;
    text-align: center;
    line-height: 40px;
    margin-bottom: 5px;
}

button {
    padding: 5px 10px;
    cursor: pointer;
}

.resaltar {
    background: yellow;
    font-weight: bold;
}

input {
    padding: 5px;
}