* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --bg-light: #ecf0f1;
    --text-dark: #2c3e50;
    --text-light: #7f8c8d;
    --border-color: #bdc3c7;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-light);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 2rem 0;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

.course-menu-home-btn {
    display: inline-block;
    margin-bottom: 0.85rem;
    padding: 0.5rem 1.1rem;
    background: rgba(255, 255, 255, 0.95);
    color: var(--primary-color);
    text-decoration: none;
    border-radius: 6px;
    font-weight: 600;
    font-size: 0.9rem;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.15);
    transition: background 0.2s, transform 0.15s;
}

.course-menu-home-btn:hover {
    background: #fff;
    transform: translateY(-1px);
}

.course-menu-home-btn--fixed {
    position: fixed;
    top: 12px;
    left: 12px;
    z-index: 1001;
    margin-bottom: 0;
}

/* Main Content */
main {
    padding: 2rem 0;
    min-height: calc(100vh - 200px);
}

/* Course Cards */
.courses-section h2 {
    margin-bottom: 2rem;
    color: var(--primary-color);
    font-size: 2rem;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
}

.course-card {
    background: white;
    border-radius: 10px;
    padding: 2rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
    cursor: pointer;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 15px rgba(0,0,0,0.2);
}

.course-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.course-card h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.course-description {
    color: var(--text-light);
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.course-meta {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    font-size: 0.9rem;
    color: var(--text-light);
}

.course-progress {
    margin-top: 1rem;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background-color: var(--bg-light);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--secondary-color), var(--success-color));
    transition: width 0.3s;
}

.progress-text {
    font-size: 0.85rem;
    color: var(--text-light);
}

/* Course Page */
.course-header {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    margin-bottom: 2rem;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.course-header h1 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.course-nav {
    background: white;
    padding: 1.5rem;
    border-radius: 10px;
    margin-bottom: 2rem;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.nav-list {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
}

.nav-item {
    padding: 0.75rem 1.5rem;
    background: var(--bg-light);
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s;
    border: 2px solid transparent;
}

.nav-item:hover {
    background: var(--secondary-color);
    color: white;
}

.nav-item.active {
    background: var(--secondary-color);
    color: white;
    border-color: var(--primary-color);
}

.nav-item.completed {
    background: var(--success-color);
    color: white;
}

.nav-item.completed::after {
    content: " ✓";
}

.nav-item.locked {
    background: #e8e8e8;
    color: #95a5a6;
    border: 1px dashed #bdc3c7;
}

.nav-item.locked::before {
    content: "🔒 ";
    font-size: 0.85em;
}

.nav-item.available:not(.active):not(.completed) {
    background: var(--bg-light);
}

.quiz-hint {
    margin-top: 0.75rem;
    font-size: 0.9rem;
    color: #555;
}

/* Module Content */
.module-content {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    margin-bottom: 2rem;
}

.module-content h2 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 3px solid var(--secondary-color);
}

.module-content h3 {
    color: var(--secondary-color);
    margin-top: 1.5rem;
    margin-bottom: 1rem;
}

.module-content p {
    margin-bottom: 1rem;
    text-align: justify;
    line-height: 1.8;
}

.module-content ul, .module-content ol {
    margin-left: 2rem;
    margin-bottom: 1rem;
}

.module-content li {
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

/* Multimedia */
.multimedia-container {
    margin: 2rem 0;
    text-align: center;
}

.multimedia-container img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    margin: 1rem 0;
}

.video-container {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    margin: 2rem 0;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    background: #000;
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

.video-title {
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}

.video-description {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 1rem;
    font-style: italic;
}

.diagram-container {
    background: var(--bg-light);
    padding: 1.5rem;
    border-radius: 8px;
    margin: 1.5rem 0;
}

.diagram-container img {
    max-width: 100%;
    height: auto;
}

/* Quiz Section */
.quiz-section {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    margin: 2rem 0;
    position: relative;
    z-index: 1;
}

.quiz-section h3 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.question {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--bg-light);
    border-radius: 8px;
    border-left: 4px solid var(--secondary-color);
    position: relative;
    overflow: visible;
}

.question-text {
    font-weight: bold;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.answer-option {
    display: flex;
    align-items: flex-start;
    margin: 0.75rem 0;
    padding: 0.75rem 1rem;
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s;
    position: relative;
    word-wrap: break-word;
    overflow: visible;
    min-height: 44px;
    width: 100%;
    line-height: 1.5;
    user-select: none;
}

.answer-option:hover {
    border-color: var(--secondary-color);
    background: #e8f4f8;
    transform: translateX(5px);
}

.answer-option input[type="radio"] {
    margin-right: 0.75rem;
    flex-shrink: 0;
    cursor: pointer;
    margin-top: 0.25rem;
    margin-bottom: 0;
    pointer-events: auto;
}

.answer-option.correct {
    background: #d4edda;
    border-color: var(--success-color);
}

.answer-option.incorrect {
    background: #f8d7da;
    border-color: var(--accent-color);
}

.quiz-actions {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
    margin-bottom: 1rem;
    padding: 1rem 0;
    position: relative;
    z-index: 2;
}

.quiz-actions .btn-primary {
    min-width: 220px;
}

.btn {
    padding: 0.75rem 2rem;
    border: none;
    border-radius: 5px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: bold;
}

.btn-primary {
    background: var(--secondary-color);
    color: white;
}

.btn-primary:hover {
    background: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

.btn-success {
    background: var(--success-color);
    color: white;
}

.btn-success:hover {
    background: #229954;
}

.btn-secondary {
    background: var(--text-light);
    color: white;
}

.quiz-result {
    margin-top: 1.5rem;
    padding: 1.5rem;
    border-radius: 8px;
    text-align: center;
    font-size: 1.2rem;
    font-weight: bold;
}

.quiz-result.passed {
    background: #d4edda;
    color: var(--success-color);
    border: 2px solid var(--success-color);
}

.quiz-result.failed {
    background: #f8d7da;
    color: var(--accent-color);
    border: 2px solid var(--accent-color);
}

/* Navigation Buttons */
.module-navigation {
    display: flex;
    justify-content: space-between;
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 2px solid var(--border-color);
}

/* Certificate Section */
.certificate-section {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 3rem;
    border-radius: 10px;
    text-align: center;
    margin: 2rem 0;
    box-shadow: 0 8px 15px rgba(0,0,0,0.2);
}

.certificate-section h2 {
    margin-bottom: 1rem;
    font-size: 2rem;
}

.certificate-section p {
    margin-bottom: 2rem;
    font-size: 1.1rem;
}

.btn-certificate {
    background: white;
    color: var(--primary-color);
    padding: 1rem 3rem;
    font-size: 1.2rem;
    border-radius: 50px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
}

.btn-certificate:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.4);
}

/* Footer */
footer {
    background: var(--primary-color);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 3rem;
}

/* Responsive */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.8rem;
    }
    
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .nav-list {
        flex-direction: column;
    }
    
    .module-navigation {
        flex-direction: column;
        gap: 1rem;
    }
    
    .btn {
        width: 100%;
    }
}

/* Table Styles */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
}

table th, table td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

table th {
    background: var(--secondary-color);
    color: white;
    font-weight: bold;
}

table tr:hover {
    background: var(--bg-light);
}

/* Code/Technical Terms */
.technical-term {
    background: #f4f4f4;
    padding: 0.2rem 0.5rem;
    border-radius: 3px;
    font-family: 'Courier New', monospace;
    font-weight: bold;
    color: var(--primary-color);
}

.highlight-box {
    background: #fff3cd;
    border-left: 4px solid var(--warning-color);
    padding: 1rem;
    margin: 1.5rem 0;
    border-radius: 5px;
}

.info-box {
    background: #d1ecf1;
    border-left: 4px solid var(--secondary-color);
    padding: 1rem;
    margin: 1.5rem 0;
    border-radius: 5px;
}

.success-box {
    background: #d4edda;
    border-left: 4px solid var(--success-color);
    padding: 1rem;
    margin: 1.5rem 0;
    border-radius: 5px;
}