body {
    background-color: #f8f9fa;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    margin-top: 50px;
}

.card {
    border: none;
    border-radius: 15px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transition: background-color 0.3s, color 0.3s;
}

.card-title {
    font-size: 1.5rem;
    font-weight: bold;
    margin-bottom: 20px;
}

.form-control {
    border-radius: 10px;
    transition: background-color 0.3s, color 0.3s;
}

.btn {
    border-radius: 10px;
    font-size: 1rem;
    font-weight: bold;
    transition: background-color 0.3s, color 0.3s;
}

.btn-primary {
    background-color: #007bff;
    border-color: #007bff;
}

.btn-primary:hover {
    background-color: #0056b3;
    border-color: #0056b3;
}

#response {
    font-size: 1rem;
    margin-top: 20px;
    text-align: center;
}

.spinner-border {
    display: none;
    width: 3rem;
    height: 3rem;
    border-width: 1.2rem;
    transition: background-color 0.3s, color 0.3s;
}

.dark-mode {
    background-color: #000000;
    color: #e0e0e0;
}

.card.dark-mode {
    background-color: #1a1a1a;
    color: #e0e0e0;
}

.form-control.dark-mode,
.btn.dark-mode,
.h-captcha.dark-mode {
    background-color: #1a1a1a;
    color: #e0e0e0;
}

.form-control.dark-mode::placeholder {
    color: #bfbfbf;
}

/* Botón de Modo Oscuro */
.btn-dark-mode {
    position: fixed;
    top: 20px;
    left: 20px;
    font-size: 1.5rem;
    border: none;
    background-color: transparent;
    color: #333; /* Color del botón */
    cursor: pointer;
    z-index: 1000;
    transition: color 0.3s;
}

/* Ícono de Luna */
.btn-dark-mode::before {
    content: '\1F319'; /* Código Unicode para la luna */
}

/* Modo oscuro para el botón de modo oscuro */
.btn-dark-mode.dark-mode {
    color: #e0e0e0;
}