*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body{
    font-family: Arial, "Helvetica Neue", Helvetica, sans-serif;
    color: #333333;
    line-height: 1.6;
}

.boton-regresar:hover {
    background-color: #0b5ed7;
    color: white;
}
.encabezado-principal{
    background-color: #ffffff;
    padding: 15px 5%;
    border-bottom: 1px solid #eee;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
#logo{
    color: aqua;
    font-size: 1.8rem;
}
#logo span{
    color: #4398db;
}
.banner-ofertas{
    background-color: #f39c12;
    color: #ffffff;
    text-align: center;
    padding: 10px 15px;
    border-bottom: 3px solid #d35400;
    font-weight: bolder;
    font-size: 0.9rem;
    position: sticky;
    top: 0;
    z-index: 100;
}
.hero{
    background: linear-gradient(135deg, #2c3e50, #4398db);
    color: #ffffff;
    padding: 60px 20px;
    text-align: center;
}
.btn-principal{
    background-color: #27ae60;
    color: #ffffff;
    border: none;
    padding: 12px 25px;
    border-radius: 5px;
    font-size: 1rem;
    font-weight: bold;
    margin-top: 15px;
    cursor: pointer;
    transition: background-color 0.2s ease;
}
.btn-principal:hover{
    background-color: #219150;
}
.seccion-cursos{
    padding: 40px 5%;
}
.seccion-cursos h2{
    color: #2c3e50;
    margin-bottom: 20px;
}
.grid-cursos{
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 15px;
    margin-top: 20px;
}
.tarjeta-cursos{
    background-color: #ffffff;
    padding: 25px;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    transition: transform 0.3s ease;
}
.tarjeta-cursos:hover{
    transform: translateY(-8px);
    box-shadow: 0 12px 15px rgba(0,0,0,0.1);
}
.tarjeta-cursos.destacado{
    border: 2px solid #4398db;
    position: relative;
}
.tarjeta-cursos.destacado::before{
    content: "¡MÁS POPULAR!";
    position: absolute;
    top: -13px;
    right: 12px;
    background-color: #e74c3c;
    color: #ffffff;
    font-size: 0.7rem;
    font-weight: bold;
    padding: 3px 8px;
    border-radius: 3px;
}
.precio{
    display: inline-block;
    margin-top: 15px;
    font-size: 1.2rem;
    font-weight: bold;
    color: #27ae60;
}
.menu-nav ul{
    list-style: none;
    display: flex;
    gap: 20px;
}
.menu-nav a{
    text-decoration: none;
    color: #2c3e50;
    font-weight: 600;
    padding: 5px 10px;
}
.pie-pagina{
    background-color: #1a252f;
    color: #ffffff;
    text-align: center;
    padding: 20px 8px;
    margin-top: 40px;
}
@media(max-width: 768px){
    .encabezado-principal{
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }
    .grid-cursos{
        grid-template-columns: 1fr;
    }
}