body {
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    color: #333;
}

.container {
    width: 80%;
    margin: auto;
    overflow: hidden;
    padding: 20px;
    background-color: #fff;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
    margin-top: 20px;
    margin-bottom: 20px;
    border-radius: 8px;
}

header {
    background: #0056b3; /* Un azul institucional */
    color: #fff;
    padding: 1rem 0;
    text-align: center;
    border-bottom: #0779e4 3px solid;
}

header h1 {
    margin: 0;
    font-size: 2.5em;
}
header p {
    font-size: 1.1em;
}

nav.main-nav ul {
    padding: 0;
    list-style: none;
    text-align: center;
    background: #333;
    margin-bottom: 20px;
}

nav.main-nav ul li {
    display: inline;
}

nav.main-nav ul li a {
    color: #fff;
    padding: 15px 20px;
    display: inline-block;
    text-decoration: none;
}

nav.main-nav ul li a:hover {
    background: #0056b3;
}

h2, h3, h4 {
    color: #0056b3;
}

h2 {
    border-bottom: 2px solid #eee;
    padding-bottom: 10px;
    margin-top: 30px;
}

h3 {
    margin-top: 25px;
}

.unit-section {
    background: #eef;
    padding: 15px;
    margin-bottom: 20px;
    border-left: 5px solid #0056b3;
    border-radius: 5px;
}

.week-link {
    display: block;
    margin: 8px 0;
    padding: 10px;
    background-color: #e9ecef;
    border-radius: 5px;
    text-decoration: none;
    color: #0056b3;
    font-weight: bold;
    transition: background-color 0.3s ease;
}

.week-link:hover {
    background-color: #ced4da;
}

.content-section {
    margin-bottom: 20px;
}

.concepts ul, .reflection ol, .activity ul, .resources ul {
    margin-left: 20px;
    padding-left: 0;
}

.concepts li, .reflection li, .activity li, .resources li {
    margin-bottom: 8px;
}

.activity, .resources, .reflection-box {
    background-color: #f9f9f9;
    border: 1px solid #ddd;
    padding: 15px;
    margin-top: 15px;
    border-radius: 5px;
}

.nav-links {
    margin-top: 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 20px;
    border-top: 1px solid #eee;
}

.nav-links a {
    text-decoration: none;
    padding: 10px 18px;
    background-color: #007bff;
    color: white;
    border-radius: 5px;
    transition: background-color 0.3s ease;
}

.nav-links a:hover {
    background-color: #0056b3;
}

.nav-links .disabled {
    background-color: #ccc;
    cursor: not-allowed;
}

.nav-links .home-link {
     background-color: #5cb85c; /* Verde */
}
.nav-links .home-link:hover {
    background-color: #4cae4c;
}


footer {
    text-align: center;
    padding: 20px;
    background: #333;
    color: #fff;
    margin-top: 30px;
}