/* ============================================================
   ESTILOS GENERALES - MATEMÁTICAS FINANCIERAS LATAM
   ============================================================ */

body {
    font-family: 'Segoe UI', Arial, sans-serif;
    margin: 0;
    background-color: #f4f6f9;
    color: #1b263b;
    line-height: 1.6;
}

/* HEADER (Estilizado y profesional) */
header {
    background-color: #0d1b2a;
    color: white;
    padding: 25px 15px;
    text-align: center;
    border-bottom: 3px solid #ffd60a;
}

.logo {
    max-width: 280px; /* Tamaño optimizado para elegancia */
    height: auto;
    display: block;
    margin: 0 auto 12px auto;
    filter: drop-shadow(0 4px 8px rgba(0,0,0,0.3));
}

header p {
    margin: 5px 0;
    font-size: 17px;
    opacity: 0.95;
    font-weight: 300;
}

/* NAVEGACIÓN */
nav {
    background-color: #1b263b;
    padding: 14px 12px;
    text-align: center;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

nav a {
    color: white;
    margin: 0 15px;
    text-decoration: none;
    font-weight: bold;
    display: inline-block;
    transition: 0.3s;
}

nav a:hover, nav a.active {
    color: #ffd60a;
}

.nav-whatsapp {
    background: #25D366;
    color: white !important;
    padding: 8px 18px;
    border-radius: 999px;
    margin-left: 10px;
    transition: transform 0.2s;
}

.nav-whatsapp:hover {
    transform: scale(1.05);
    background: #20ba5a;
}

/* SECCIONES */
section {
    padding: 50px 20px;
    max-width: 1000px;
    margin: auto;
}

h2 {
    color: #0d1b2a;
    font-size: 28px;
    border-left: 5px solid #ffd60a;
    padding-left: 15px;
    margin-bottom: 25px;
}

h3 {
    color: #1b263b;
    margin-top: 25px;
}

/* LISTAS Y TEMAS */
ul {
    padding-left: 25px;
}

.topics-columns {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px 35px;
    list-style-type: square;
}

/* NOTA PARCIALES */
.nota-parciales {
    margin-top: 30px;
    background: #fff4d6;
    border: 1px solid #ffd60a;
    padding: 18px;
    border-radius: 12px;
    font-size: 15px;
    color: #856404;
}

/* FORMULARIO / BUZÓN PRO */
.form-box {
    background: white;
    border-radius: 18px;
    padding: 30px;
    max-width: 850px;
    margin: 25px auto;
    box-shadow: 0 15px 35px rgba(0,0,0,0.08);
    border: 1px solid rgba(0,0,0,0.05);
}

.form-subtitle {
    margin-bottom: 20px;
    color: #2b3a55;
    font-weight: 500;
}

.contact-form label {
    display: block;
    font-weight: bold;
    margin: 15px 0 6px 0;
    font-size: 14px;
}

.form-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

input, textarea {
    width: 100%;
    box-sizing: border-box;
    padding: 14px;
    border-radius: 10px;
    border: 1px solid #d1d9e6;
    font-size: 15px;
    background: #fdfeff;
    transition: 0.3s;
}

input:focus, textarea:focus {
    border-color: #1b263b;
    box-shadow: 0 0 0 4px rgba(27,38,59,0.1);
    outline: none;
}

button {
    margin-top: 20px;
    padding: 15px 25px;
    border: none;
    border-radius: 10px;
    background: #1b263b;
    color: white;
    font-weight: bold;
    font-size: 16px;
    cursor: pointer;
    width: 100%;
    transition: 0.3s;
}

button:hover {
    background: #0d1b2a;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

/* DASHBOARDS Y TARJETAS */
.dash-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
    margin-top: 20px;
}

.dash-card {
    background: #ffffff;
    border-radius: 16px;
    overflow: hidden;
    border: 1px solid rgba(0,0,0,0.06);
    box-shadow: 0 10px 25px rgba(0,0,0,0.05);
    transition: transform 0.3s ease;
}

.dash-card:hover {
    transform: translateY(-5px);
}

.dash-img {
    width: 100%;
    height: auto;
    display: block;
}

.dash-caption {
    padding: 18px;
    color: #1b263b;
}

/* FOOTER */
footer {
    background-color: #0d1b2a;
    color: white;
    padding: 40px 20px;
    text-align: center;
    margin-top: 50px;
}

.footer-contact {
    margin: 15px 0;
    font-size: 15px;
    opacity: 0.9;
}

/* WHATSAPP FLOTANTE */
.whatsapp-float {
    position: fixed;
    right: 25px;
    bottom: 25px;
    z-index: 9999;
    background: #25D366;
    color: white;
    padding: 16px 22px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: bold;
    box-shadow: 0 10px 25px rgba(37,211,102,0.4);
    display: flex;
    align-items: center;
    gap: 10px;
    transition: 0.3s;
}

.whatsapp-float:hover {
    transform: scale(1.1);
}

/* RESPONSIVE (Móviles) */
@media (max-width: 768px) {
    nav a {
        display: block;
        margin: 12px 0;
    }

    .nav-whatsapp {
        margin-left: 0;
        display: inline-block;
    }

    .topics-columns, .form-grid, .dash-grid {
        grid-template-columns: 1fr;
    }

    .logo {
        max-width: 220px;
    }

    section {
        padding: 35px 15px;
    }
}