* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
body {
    font-family: Arial, sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column; 
}
.header {
    background-color: #333;
    color: #fff;
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.logo {
    font-size: 1.5rem;
    font-weight: bold;
}
.menu {
    display: flex;
    gap: 20px;
}
.menu a {
    color: #fff;
    text-decoration: none;
}
.main {
    flex: 1; 
    display: flex;
    gap: 20px;
    padding: 20px;
    background-color: #f4f4f4;
}
.sidebar {
    flex: 0 0 250px; 
    background-color: #ddd;
    padding: 15px;
    border-radius: 5px;
}
.contenido {
    flex: 1;
}
.sidebar ul {
    list-style: none;
    margin-top: 10px;
}
.sidebar li {
    margin-bottom: 5px;
}
.cards {
    display: flex;
    gap: 20px;
    margin-top: 15px;
}
.card {
    flex: 1;
    background-color: white;
    padding: 20px;
    border: 1px solid #ccc;
    border-radius: 5px;
    text-align: center;
}
.footer {
    background-color: #222;
    color: #aaa;
    padding: 20px;
    border-top: 5px solid #444;
    display: flex;
    justify-content: space-between;
    align-items: center;
}