:root {
    color-scheme: dark;
    font-size: 1rem;
    font-family: "Inter", sans-serif;
    font-optical-sizing: auto;
    font-weight: normal;
    font-style: normal;
    --primary-color: #1e5b62; /* Verde oscuro */
    --secondary-color: #6cdbe5; /* Azul claro */
    --button-color: #6cdbe5; /* Azul claro para botones */
    --nav-bg-color: linear-gradient(90deg, #1e5b62, #0ecce1); /* Degradado para la barra de navegación */
    --footer-bg-color: linear-gradient(90deg, #1e5b62, #6cdbe5); /* Degradado para el pie de página */
    --error-color: #D50000; /* Rojo brillante */
    --background-light: linear-gradient(180deg, #e7f2f3, #cfe8ea); /* Fondo claro con degradado */
    --background-dark: linear-gradient(180deg, #0b1617, #1e5b62); /* Fondo oscuro con degradado */
    --text-light: #111818; /* Texto oscuro */
    --text-dark: #111818; /* Texto oscuro */
    --card-bg: linear-gradient(135deg, #6cdbe5, #0ecce1); /* Fondo de tarjetas con degradado */
    --button-hover: linear-gradient(90deg, #0ecce1, #6cdbe5); /* Hover de botones con degradado */
}

body {
    display: flex;
    flex-direction: column;
    margin: 0;
    min-height: 100vh;
    background: var(--background-light);
    color: var(--text-light);
    transition: background 0.3s ease, color 0.3s ease;
}

nav {
    background: var(--nav-bg-color);
    text-align: center;
    padding: 1rem;
    font-size: 2rem;
    color: var(--text-light);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
    border-bottom: 2px solid var(--primary-color);
}

.score-info {
    text-align: center;
}
.score-info p {
    color: white;
}

nav span a {
    text-decoration: none;
    color: var(--text-light);
    font-weight: bold;
    transition: color 0.3s ease;
}

nav span a:hover {
    color: var(--primary-color);
}

footer {
    background: var(--footer-bg-color);
    text-align: center;
    padding: 1rem;
    font-size: 1.2rem;
    color: var(--text-light);
    box-shadow: 0 -4px 12px rgba(0, 0, 0, 0.5);
    border-top: 2px solid var(--primary-color);
}

main {
    flex-grow: 1;
    align-content: center;
    padding: 20px;
    background: var(--background-dark);
    transition: background 0.3s ease;
    box-shadow: inset 0 0 15px rgba(0, 0, 0, 0.7);
}

#translateBtn {
    display: none;
    margin: 0 auto;
    padding: 0.8rem 1.5rem;
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 100;
    border-radius: 50px;
    border: none;
    font-size: 1rem;
    background: var(--primary-color);
    color: var(--text-light);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
    cursor: pointer;
    transition: all 0.3s ease;
}

#translateBtn:hover {
    background: var(--button-hover);
    transform: translateY(-3px);
}

#question-container {
    max-width: 80%;
    margin: 20px auto;
    padding: 20px;
    background: var(--card-bg);
    border-radius: 15px;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.6);
}

div h2 {
    width: 90%;
    margin: 0 auto;
    text-align: center;
    padding: 10px 0;
    font-size: 2rem;
    color: var(--text-light);
    border-bottom: 2px solid var(--primary-color);
}

ul {
    margin: 0;
    padding: 0;
    list-style: none;
    display: flex;
    flex-direction: column;
    align-items: center;
}

li {
    background: var(--secondary-color);
    margin: 10px 0;
    padding: 15px;
    border-radius: 12px;
    color: var(--text-light);
    text-align: center;
    width: 70%;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
    transition: transform 0.3s ease, background 0.3s ease;
}

li:hover {
    background: var(--button-hover);
    transform: scale(1.05);
}

.opts {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    margin: 20px 0;
}

.opts button {
    border: none;
    padding: 15px;
    border-radius: 12px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    background: var(--button-color);
    color: var(--text-light);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
}

.opts button:hover {
    background: var(--button-hover);
    transform: scale(1.1);
}

button.correct {
    background: var(--primary-color) !important;
    color: var(--text-light) !important;
    font-weight: bold;
}

button.incorrect {
    background: var(--error-color) !important;
    color: var(--text-light) !important;
}

question-counter {
    text-align: center;
    font-weight: bold;
    margin-bottom: 10px;
    font-size: 1.4rem;
    color: var(--text-light);
}

#navigation-container {
    text-align: center;
    margin-top: 20px;
}

#next-button,
#restart-button,
#clear-button {
    background: var(--secondary-color);
    color: var(--text-light);
    border: none;
    padding: 12px 25px;
    border-radius: 50px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    margin: 0 10px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
}

#next-button:disabled,
#restart-button:disabled {
    background: #555555 !important;
    color: #888888 !important;
    cursor: not-allowed;
    opacity: 0.8;
}

#next-button:not(:disabled):hover,
#restart-button:not(:disabled):hover,
#clear-button:hover {
    background: var(--button-hover);
    transform: translateY(-3px);
}

@media screen and (min-width: 1024px) {
    .opts {
        grid-template-columns: repeat(2, 1fr);
    }

    div h2 {
        font-size: 2.5rem;
    }

    #translateBtn {
        font-size: 1.2rem;
    }
}