/* Base Styles */
body {
    font-family: 'Poppins', sans-serif;
    /* Premium gradient - Deep Blue/Purple */
    background: linear-gradient(135deg, #2c3e50 0%, #4a0e4e 100%); /* Dark Blue to Deep Purple */
    color: #e0e0e0; /* Lighter text for dark background */
    margin: 0;
    padding: 20px;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
}

.container {
    background-color: rgba(52, 73, 94, 0.85); /* Semi-transparent dark blue-grey */
    padding: 35px 45px;
    border-radius: 12px;
    box-shadow: 0 10px 35px rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.15);
    max-width: 700px;
    width: 90%;
    text-align: center;
    margin-top: 30px;
    backdrop-filter: blur(5px); /* Optional blur effect */
}

header h1 {
    font-size: 2.3em;
    margin-bottom: 10px;
    font-weight: 700;
    color: #f1c40f; /* Gold/Yellow Accent */
    text-shadow: 1px 1px 3px rgba(0,0,0,0.5);
}
header h1 i { /* Crown Icon */
    margin-right: 10px;
    opacity: 0.8;
}

header p {
    font-size: 1.1em;
    margin-bottom: 35px;
    color: #bdc3c7; /* Light grey */
}

/* Form Styling */
#quiz-setup-form {
    text-align: left;
}

.form-section {
    background-color: rgba(44, 62, 80, 0.8); /* Slightly darker transparent section bg */
    padding: 25px;
    border-radius: 8px;
    margin-bottom: 30px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.form-section h2 {
    margin-top: 0;
    margin-bottom: 20px;
    font-size: 1.6em;
    color: #ecf0f1; /* Light text for headings */
    border-bottom: 2px solid #f1c40f; /* Gold accent border */
    padding-bottom: 10px;
    display: flex; /* Align icon */
    align-items: center;
}
.form-section h2 i {
    margin-right: 12px;
    color: #f1c40f; /* Gold icon */
}

.section-description { /* Added for topic section */
    color: #bdc3c7;
    font-size: 0.95em;
    margin-bottom: 15px;
    margin-top: -10px; /* Pull up slightly */
}

.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    margin-bottom: 10px;
    font-weight: 600;
    color: #ecf0f1; /* Light label text */
    font-size: 1.05em;
}

.form-group input[type="number"] {
    width: calc(100% - 24px);
    padding: 12px 12px;
    border: 1px solid #7f8c8d; /* Grey border */
    border-radius: 5px;
    font-size: 1em;
    transition: border-color 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
    background-color: #ecf0f1; /* Light background for input */
    color: #2c3e50; /* Dark text inside input */
}
.form-group input[type="number"]::placeholder {
    color: #95a5a6;
}

.form-group input[type="number"]:focus {
    border-color: #f1c40f; /* Gold border on focus */
    outline: 0;
    box-shadow: 0 0 0 0.2rem rgba(241, 196, 15, 0.25); /* Gold focus ring */
}

/* Topic Selection Styling */
.topic-selection {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); /* Responsive grid */
    gap: 15px;
    margin-top: 10px;
}

.checkbox-label {
    display: flex;
    align-items: center;
    background-color: rgba(236, 240, 241, 0.1); /* Very subtle light bg */
    padding: 12px 15px;
    border-radius: 5px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    cursor: pointer;
    transition: background-color 0.2s ease, border-color 0.2s ease;
    color: #ecf0f1; /* Light text */
    font-weight: 500;
    position: relative;
}

.checkbox-label:hover {
    background-color: rgba(236, 240, 241, 0.2);
    border-color: #f1c40f; /* Gold highlight on hover */
}

.checkbox-label input[type="checkbox"] {
    opacity: 0;
    position: absolute;
}

.checkbox-custom {
    display: inline-block;
    width: 18px;
    height: 18px;
    border: 2px solid #bdc3c7; /* Light grey border */
    border-radius: 3px;
    margin-right: 10px;
    transition: background-color 0.2s ease, border-color 0.2s ease;
    flex-shrink: 0;
}
.checkbox-label i { /* Icon styling */
     margin-right: 8px;
     color: #bdc3c7; /* Default icon color */
     width: 20px;
     text-align: center;
     transition: color 0.2s ease;
}

.checkbox-label input[type="checkbox"]:checked + .checkbox-custom {
    background-color: #f1c40f; /* Gold check background */
    border-color: #f1c40f;
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 8 8'%3e%3cpath fill='%232c3e50' d='M6.564.75l-3.59 3.6-1.5-1.5L0 4.26 2.974 7.25 8 2.193z'/%3e%3c/svg%3e"); /* Dark checkmark */
    background-repeat: no-repeat;
    background-position: center center;
    background-size: 50% 50%;
}
.checkbox-label input[type="checkbox"]:checked ~ i { /* Change icon color when checked */
     color: #f1c40f;
}


.checkbox-label input[type="checkbox"]:focus + .checkbox-custom {
     box-shadow: 0 0 0 0.2rem rgba(241, 196, 15, 0.25); /* Gold focus ring */
}

/* Error Message Styling */
.error-message {
    color: #e74c3c; /* Premium-looking error red */
    font-size: 0.85em;
    display: block;
    margin-top: 8px;
    min-height: 1.2em;
    font-weight: 500;
}

/* Input with error */
input.input-error { border-color: #e74c3c; }
input.input-error:focus { box-shadow: 0 0 0 0.2rem rgba(231, 76, 60, 0.25); }
.topic-selection.input-error { /* Error style for topic container */
     border: 1px solid #e74c3c;
     border-radius: 5px;
     padding: 5px;
}

/* Action Buttons */
.form-actions {
    display: flex;
    justify-content: space-between;
    margin-top: 35px;
    padding-top: 25px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.button {
    padding: 12px 28px; /* Slightly more padding */
    border: none;
    border-radius: 25px;
    font-size: 1.05em; /* Slightly larger font */
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px; /* Space between text and icon */
}

.primary-button {
    /* Premium purple/dark gradient */
    background: linear-gradient(45deg, #8e44ad, #5e3370); /* Purple gradient */
    color: white;
    border: 1px solid rgba(255,255,255, 0.1); /* Subtle border */
}

.primary-button:hover {
    background: linear-gradient(45deg, #7b3099, #4a245c); /* Darker purple */
    transform: translateY(-2px) scale(1.02); /* Lift and slightly grow */
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.25);
}

.secondary-button {
    background-color: #7f8c8d; /* Grey */
    color: #ecf0f1;
    border: 1px solid rgba(255,255,255, 0.1);
}

.secondary-button:hover {
    background-color: #6c7a7d;
    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.15);
}

/* Responsive Adjustments */
@media (max-width: 768px) {
    .container { padding: 25px 20px; }
    header h1 { font-size: 1.9em; }
    .topic-selection { grid-template-columns: 1fr; }
    .form-actions { flex-direction: column-reverse; gap: 15px; align-items: center; }
    .button { width: 90%; }
}