*{
    margin: 0;
    padding: 0;
}
*,*::before,*::after{
    box-sizing: border-box;
}

body{
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: #333333;
    line-height: 1.6;
    background-color: #f4f7f6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* encabezado */
.encabezado-principal{
    background: linear-gradient(135deg, #c072c0, #772563);
    color: #ffffff;
    text-align: center;
    padding: 40px 5% 25px;
}
#logo{
    font-size: 2.2rem;
    margin-bottom: 8px;
}
.nombre{
    color: #ecf0f1;
    margin-bottom: 25px;
}

/* menú */
.menu-nav ul{
    list-style: none;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 12px;
}
.menu-nav a{
    display: inline-block;
    padding: 10px 20px;
    color: #ffffff;
    text-decoration: none;
    font-weight: 600;
    border: 2px solid rgba(255, 255, 255, 0.6);
    border-radius: 25px;
    transition: background-color 0.3s ease, transform 0.3s ease;
}
.menu-nav a:hover{
    background-color: #0000ff;
    border-color: #0000ff;
    transform: translateY(-3px);
}
.menu-nav a:active,
.menu-nav a:focus{
    background-color: #e74c3c;
    border-color: #e74c3c;
}

/* contenido */
main{
    flex: 1;
}
.seccion-practicas{
    max-width: 800px;
    margin: 0 auto;
    padding: 50px 5%;
    text-align: center;
}
.seccion-practicas h2{
    color: #2c3e50;
    margin-bottom: 25px;
}
.grid-practicas{
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 25px;
}
.tarjeta-practica{
    display: block;
    background-color: #ffffff;
    color: #2c3e50;
    text-decoration: none;
    font-weight: bold;
    font-size: 1.1rem;
    padding: 30px 20px;
    border: 1px solid #e0e0e0;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease, color 0.3s ease;
}
.tarjeta-practica:hover{
    transform: translateY(-8px);
    box-shadow: 0 12px 20px rgba(0, 0, 0, 0.15);
    color: #3498db;
}

/* pie de página */
.pie-pagina{
    background-color: #1a252f;
    color: #ffffff;
    text-align: center;
    padding: 20px;
}
/* flecha para salir */
.flecha-regresar{
    display: inline-block;
    color: #ffffff;
    text-decoration: none;
    font-weight: 600;
    padding: 8px 16px;
    border: 2px solid rgba(255, 255, 255, 0.6);
    border-radius: 25px;
    margin-bottom: 15px;
    transition: background-color 0.3s ease, transform 0.3s ease;
}
.flecha-regresar:hover{
    background-color: #0000ff;
    border-color: #0000ff;
    transform: translateX(-5px);   /* la flecha "se va" hacia la izquierda */
}
.flecha-regresar:active,
.flecha-regresar:focus{
    background-color: #e74c3c;
    border-color: #e74c3c;
}

/* lista de compras */
.seccion-lista{
    max-width: 700px;
    margin: 0 auto;
    padding: 40px 5%;
}
.lista-principal{
    list-style: none;
}
.lista-principal > li{
    background-color: #ffffff;
    border: 1px solid #e0e0e0;
    border-left: 5px solid #3498db;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    padding: 20px 25px;
    margin-bottom: 20px;
    font-weight: bold;
    color: #2c3e50;
}
.lista-principal ol{
    margin: 10px 0 0 25px;
    font-weight: normal;
    color: #333333;
}
.lista-principal ol li{
    padding: 3px 0;
}

/* flecha de abajo (fondo claro) */
.flecha-arriba{
    color: #2c3e50;
    border-color: #2c3e50;
}
/* artículo */
.seccion-articulo{
    max-width: 700px;
    margin: 0 auto;
    padding: 40px 5% 20px;
}
.seccion-articulo h2{
    color: #2c3e50;
    margin-bottom: 10px;
}
.seccion-articulo a{
    color: #3498db;
    font-weight: 600;
}
.seccion-articulo a:hover{
    color: #0000ff;
}
.seccion-articulo a:active{
    color: #e74c3c;
}

/* imagen */
.contenedor-imagen{
    max-width: 700px;
    margin: 0 auto;
    padding: 0 5% 40px;
    text-align: center;
}
.contenedor-imagen img{
    max-width: 100%;
    height: auto;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}
/* Diseño Responsive */
@media(max-width:768px){
    #logo{
        font-size: 1.5rem;
    }
    .menu-nav ul{
        flex-direction: column;
        align-items: center;
    }
    .menu-nav a{
        width: 220px;
        text-align: center;
    }
}