* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

html, body {
    height: 100%;
}

body {
    background-color: #ffffff;
    color: #333333;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.encabezado {
    background-color: #0d1527;
    padding: 15px 20px;
    text-align: left;
}

.btn-atras {
    display: inline-block;
    padding: 8px 18px;
    background-color: #3b82f6;
    color: #ffffff;
    text-decoration: none;
    border-radius: 20px;
    font-size: 14px;
    font-family: sans-serif;
    font-weight: bold;
    transition: background-color 0.2s ease;
}

.btn-atras:hover {
    background-color: #2563eb;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 50px;
    background-color: #ffffff;
    border-bottom: 1px solid #e2e8f0;
}

.logo {
    font-size: 22px;
    font-weight: 800;
    color: #1a202c;
}

.logo span {
    color: #3182ce;
}

.nav-links {
    display: flex;
    gap: 25px;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: #4a5568;
    font-size: 14px;
}

.top-banner {
    background-color: #f6ad55;
    color: #ffffff;
    text-align: center;
    padding: 8px 10px;
    font-size: 13px;
    font-weight: 600;
}

.hero {
    background: linear-gradient(180deg, #2b4c7e 0%, #3182ce 100%);
    color: #ffffff;
    text-align: center;
    padding: 50px 20px;
}

.hero h1 {
    font-size: 26px;
    margin-bottom: 10px;
}

.hero p {
    font-size: 14px;
    opacity: 0.9;
    margin-bottom: 25px;
}

.btn-hero {
    background-color: #48bb78;
    color: #ffffff;
    border: none;
    padding: 10px 24px;
    border-radius: 4px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.1s ease;
}

.btn-hero:hover {
    background-color: #38a169;
}

.btn-hero:active {
    background-color: #276749;
    transform: scale(0.97);
}

.container {
    max-width: 1100px;
    margin: 40px auto;
    padding: 0 20px;
    flex: 1;
}

.container h2 {
    font-size: 20px;
    color: #2d3748;
    margin-bottom: 25px;
}

.cards-grid {
    display: flex;
    gap: 20px;
    justify-content: space-between;
}

.card {
    flex: 1;
    background-color: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    padding: 25px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 20px rgba(0, 0, 0, 0.15);
}

.card h3 {
    font-size: 18px;
    color: #1a202c;
    margin-bottom: 12px;
}

.card p {
    font-size: 13px;
    color: #4a5568;
    line-height: 1.5;
    margin-bottom: 20px;
}

.card .price {
    font-size: 16px;
    font-weight: 800;
    color: #3182ce;
}

.card-popular {
    border: 2px solid #3182ce;
}

.badge {
    position: absolute;
    top: -12px;
    right: 20px;
    background-color: #cc0000;
    color: #ffffff;
    font-size: 11px;
    font-weight: bold;
    padding: 3px 8px;
}

footer {
    width: 100%;
    background-color: #1a202c;
    color: #ffffff;
    text-align: center;
    padding: 20px 0;
    font-size: 13px;
}

@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        gap: 15px;
        padding: 15px 20px;
        text-align: center;
    }

    .cards-grid {
        flex-direction: column;
        gap: 25px;
    }

    .hero h1 {
        font-size: 22px;
    }

    .hero p {
        font-size: 13px;
    }
}