body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #0fd95d; /* Actualizado */
    color: #00422e; /* Actualizado */
    margin: 0;
    padding: 40px 20px;
}
.container {
    max-width: 800px;
    margin: 0 auto;
    background-color: #ffffff;
    padding: 30px 40px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
    border-top: 8px solid #0f4a30; /* Verde oscuro basado en el logo de UCSM */
}
h1 {
    color: #0f4a30;
    text-align: center;
    margin-bottom: 10px;
}
p.description {
    text-align: center;
    color: #555;
    margin-bottom: 35px;
    font-size: 1.1em;
}
.question-block {
    margin-bottom: 25px;
    padding: 20px;
    background-color: #f9faee; /* Actualizado */
    border: 1px solid #e0e0e0;
    border-left: 5px solid #a3e635; /* Verde claro vibrante del fondo del banner */
    border-radius: 6px;
    transition: box-shadow 0.2s;
}
.question-block:hover {
    box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}
.question-text {
    font-weight: 600;
    margin-bottom: 15px;
    font-size: 1.1em;
    color: #00422e; /* Actualizado */
}
.options-group {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    gap: 15px;
}
.option-label {
    display: flex;
    align-items: center;
    cursor: pointer;
    padding: 8px 15px;
    border-radius: 4px;
    transition: background-color 0.2s;
    background-color: #f9f9f9;
    border: 1px solid #eee;
}
.option-label:hover {
    background-color: #f0fdf4;
}
.option-label input {
    margin-right: 12px;
    width: 18px;
    height: 18px;
    accent-color: #0f4a30;
}
.submit-btn {
    display: block;
    width: 100%;
    padding: 16px;
    background-color: #0f4a30;
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1.1em;
    font-weight: bold;
    cursor: pointer;
    margin-top: 40px;
    transition: background-color 0.3s;
}
.submit-btn:hover {
    background-color: #0a3521;
}

/* Preloader Styles */
.preloader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #0fd95d;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    opacity: 1;
    visibility: visible;
    transition: opacity 1.5s ease-out, visibility 2s ease-out; /* Aumentado para desvanecimiento más suave */
}

.preloader.hidden {
    opacity: 0;
    visibility: hidden;
    z-index: -1;
}

.preloader-content {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 30px;
}

.preloader-logo {
    width: 500px;
    height: 500px;
    animation: pulse 2.5s ease-in-out infinite; /* Animación de pulso */
}

.preloader-spinner {
    display: none; /* Ocultamos el spinner para un look más limpio */
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}

/* Keyframes para la animación de pulso */
@keyframes pulse {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
    100% {
        transform: scale(1);
    }
}

/* --- Media Queries para Diseño Responsive --- */

/* Para tablets grandes y desktops (1200px en adelante) */
@media (min-width: 1200px) {
    .container {
        max-width: 960px;
    }
    h1 {
        font-size: 2.5em;
    }
}

/* Para tablets en modo retrato (769px a 1199px) */
@media (max-width: 1199px) {
    .container {
        max-width: 90%;
    }
    h1 {
        font-size: 2em;
    }
    p.description {
        font-size: 1em;
    }
    .question-text {
        font-size: 1.05em;
    }
    .preloader-logo {
        width: 180px;
        height: 180px;
    }
}

/* Para móviles (hasta 768px) */
@media (max-width: 768px) {
    body {
        padding: 20px 10px;
    }
    .container {
        padding: 20px 15px;
        border-top-width: 6px;
    }
    h1 {
        font-size: 1.8em;
    }
    p.description {
        font-size: 1em;
        margin-bottom: 25px;
    }
    .question-block {
        padding: 15px;
    }
    .question-text {
        font-size: 1em;
    }
    .submit-btn {
        padding: 14px;
        font-size: 1em;
    }
    .preloader-logo {
        width: 250px;
        height: 250px;
    }
}