/* Menú superior */
        .nav-custom {
            background: rgba(0,0,0,0.75);
            backdrop-filter: blur(8px);
        }

        .nav-custom a {
            color: #fff !important;
            font-weight: 500;
            margin: 0 12px;
        }

        .nav-custom a:hover {
            color: #00c8ff !important;
        }

        /* Portada principal */
        .hero {
            width: 100%;
            height: 90vh;
            background: url('A_promotional_digital_graphic_design_for_FM_Río,_a.png') no-repeat center center/cover;
            display: flex;
            justify-content: center;
            align-items: center;
            text-align: center;
            color: white;
            padding: 40px;
        }

        .hero h1 {
            font-size: 4rem;
            text-shadow: 2px 2px 20px #000;
        }

        /* Sub-portada / menú secundario */
        .sub-hero {
            background: #0b0e15;
            color: white;
            padding: 40px 0;
        }

        .sub-hero .option-box {
            background: #111520;
            padding: 20px;
            border-radius: 12px;
            text-align: center;
            transition: 0.3s;
            cursor: pointer;
        }

        .sub-hero .option-box:hover {
            background: #1b2233;
            transform: translateY(-5px);
        }

        .option-box h4 {
            margin-top: 10px;
            color: #00c8ff;
        }