:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --background-color: #f4f6f7;
    --text-color: #333;
    --card-bg: #fff;
    --success-color: #27ae60;
    --error-color: #e74c3c;
    --font-main: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    font-family: var(--font-main);
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    line-height: 1.6;
}

/* Anti-Cheating Utils */
.no-select {
    -webkit-user-select: none; /* Safari */
    -moz-user-select: none;    /* Firefox */
    -ms-user-select: none;     /* IE10+/Edge */
    user-select: none;         /* Standard */
}

@media print {
    body {
        display: none;
    }
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

.site-header {
    background-color: var(--card-bg);
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    padding: 1rem 0;
}

.site-header .logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-align: center;
}

.site-header nav ul {
    list-style: none;
    padding: 0;
    text-align: center;
    margin-top: 10px;
}

.site-header nav ul li {
    display: inline;
    margin: 0 15px;
}

.site-header nav ul li a {
    text-decoration: none;
    color: var(--secondary-color);
    font-weight: 500;
}

.upload-container, .quiz-container, .results-container {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    margin-top: 2rem;
}

.btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s;
    text-decoration: none;
    display: inline-block;
}

.btn:hover {
    background-color: #2980b9;
}

.btn:disabled {
    background-color: #bdc3c7;
    cursor: not-allowed;
}

.hidden {
    display: none;
}

.file-upload-area {
    border: 2px dashed #bdc3c7;
    border-radius: 8px;
    padding: 2rem;
    text-align: center;
    cursor: pointer;
    transition: border-color 0.3s;
}

.file-upload-area:hover {
    border-color: var(--primary-color);
}

.question-card {
    border-bottom: 1px solid #eee;
    padding-bottom: 1.5rem;
    margin-bottom: 1.5rem;
}

.option-group {
    margin-top: 10px;
}

.option-item {
    display: block;
    margin-bottom: 8px;
    cursor: pointer;
}

.site-footer {
    text-align: center;
    margin-top: 3rem;
    padding: 1rem;
    color: #7f8c8d;
    font-size: 0.9rem;
}
/* Error state for unanswered questions */
.unanswered-error {
    border: 2px solid #e74c3c !important; /* Red border */
    background-color: #fff5f5 !important; /* Light red background */
    padding: 15px !important;
    border-radius: 8px !important;
    transition: all 0.3s ease;
}