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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #f8fafc;
    color: #1e293b;
    line-height: 1.6;
}

/* NAV */
header {
    background: #1e40af;
    padding: 0 2rem;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 8px rgba(0,0,0,0.2);
}

nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1100px;
    margin: 0 auto;
    height: 60px;
}

.logo {
    color: white;
    font-size: 1.4rem;
    font-weight: 700;
    text-decoration: none;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 1.5rem;
}

nav ul a {
    color: #bfdbfe;
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.2s;
}

nav ul a:hover {
    color: white;
}

/* MAIN */
main {
    max-width: 1100px;
    margin: 0 auto;
    padding: 2rem;
}

/* HERO */
.hero {
    text-align: center;
    padding: 3rem 1rem;
}

.hero h1 {
    font-size: 2.2rem;
    color: #1e40af;
    margin-bottom: 0.8rem;
}

.hero p {
    font-size: 1.1rem;
    color: #64748b;
}

/* GRID DE HERRAMIENTAS */
.herramientas {
    margin-top: 2rem;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
}

.card {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    text-decoration: none;
    color: inherit;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    border: 1px solid #e2e8f0;
    transition: transform 0.2s, box-shadow 0.2s;
    display: block;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(30,64,175,0.12);
}

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.card h2 {
    font-size: 1.1rem;
    color: #1e40af;
    margin-bottom: 0.5rem;
}

.card p {
    font-size: 0.9rem;
    color: #64748b;
}

/* CALCULADORA PAGE */
.calculadora-page h1 {
    font-size: 1.8rem;
    color: #1e40af;
    margin-bottom: 0.4rem;
}

.subtitulo {
    color: #64748b;
    margin-bottom: 2rem;
}

.calculadora-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    border: 1px solid #e2e8f0;
    margin-bottom: 2rem;
}

.campo {
    margin-bottom: 1.2rem;
}

.campo label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: #374151;
    margin-bottom: 0.4rem;
}

.campo input, .campo select {
    width: 100%;
    padding: 0.7rem 1rem;
    border: 1px solid #d1d5db;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
    outline: none;
}

.campo input:focus, .campo select:focus {
    border-color: #1e40af;
}

button {
    width: 100%;
    padding: 0.85rem;
    background: #1e40af;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

button:hover {
    background: #1d3a9e;
}

.resultados {
    background: #eff6ff;
    border-radius: 10px;
    padding: 1.5rem;
}

.resultados h2 {
    color: #1e40af;
    margin-bottom: 1.2rem;
}

.resultado-item {
    display: flex;
    justify-content: space-between;
    padding: 0.7rem 0;
    border-bottom: 1px solid #bfdbfe;
}

.resultado-item:last-child {
    border-bottom: none;
}

.resultado-item strong {
    color: #1e40af;
    font-size: 1.1rem;
}

/* CONTENIDO SEO */
.contenido-seo {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    border: 1px solid #e2e8f0;
}

.contenido-seo h2 {
    color: #1e40af;
    margin-bottom: 1rem;
}

.contenido-seo h3 {
    color: #374151;
    margin: 1.2rem 0 0.5rem;
}

.contenido-seo p {
    color: #4b5563;
    margin-bottom: 0.8rem;
}

.contenido-seo ul {
    padding-left: 1.5rem;
    color: #4b5563;
}

.contenido-seo ul li {
    margin-bottom: 0.4rem;
}

/* FOOTER */
footer {
    text-align: center;
    padding: 2rem;
    color: #94a3b8;
    font-size: 0.85rem;
    border-top: 1px solid #e2e8f0;
    margin-top: 3rem;
}

/* RESPONSIVE */
@media (max-width: 640px) {
    .calculadora-container {
        grid-template-columns: 1fr;
    }

    nav ul {
        display: none;
    }

    .hero h1 {
        font-size: 1.6rem;
    }
}