/* Fondo general con estilo moderno y cálido */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e9f2 100%);
    margin: 0;
    padding: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

/* Contenedor principal tipo tarjeta flotante */
.container {
    background: #ffffff;
    padding: 30px;
    border-radius: 16px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.08);
    width: 100%;
    max-width: 480px;
    box-sizing: border-box;
}

/* Barra superior con botón de navegación */
.nav-bar {
    margin-bottom: 20px;
}

.btn-volver {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: #4a5568;
    background: #edf2f7;
    padding: 8px 14px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    transition: all 0.2s ease;
}

.btn-volver:hover {
    background: #cbd5e0;
    color: #2d3748;
}

/* Encabezado */
h2 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 25px;
    font-size: 24px;
}

/* Estilos de los campos del formulario */
.form-group {
    margin-bottom: 18px;
}

label {
    display: block;
    margin-bottom: 6px;
    font-weight: 600;
    color: #4a5568;
    font-size: 14px;
}

input[type="text"], input[type="file"] {
    width: 100%;
    padding: 12px;
    border: 1px solid #cbd5e0;
    border-radius: 8px;
    box-sizing: border-box;
    font-size: 14px;
    transition: border-color 0.2s;
}

input[type="text"]:focus {
    border-color: #319795;
    outline: none;
    box-shadow: 0 0 0 3px rgba(49, 151, 149, 0.15);
}

/* Botón de guardar principal */
button[type="submit"], .btn-primary {
    width: 100%;
    background-color: #319795;
    color: white;
    padding: 14px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
    margin-top: 10px;
}

button[type="submit"]:hover {
    background-color: #2c7a7b;
}

button[type="submit"]:active {
    transform: scale(0.98);
}