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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #1e4a6b 0%, #2c5d7a 100%);
    min-height: 100vh;
    color: #333;
}

.header {
    background: #1e4a6b;
    padding: 20px 0;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
    flex-wrap: wrap;
    gap: 20px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 15px;
}

.logo-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(45deg, #d4af37, #f4d03f);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    color: #1e4a6b;
    font-size: 20px;
}

.logo-text {
    color: #d4af37;
    font-size: 24px;
    font-weight: bold;
}

.logo-subtitle {
    color: #fff;
    font-size: 12px;
    margin-top: 2px;
}

.back-button {
    background: linear-gradient(135deg, #d4af37, #f4d03f);
    color: #1e4a6b;
    text-decoration: none;
    padding: 10px 20px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 14px;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
    white-space: nowrap;
}

.back-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(0,0,0,0.3);
}

.nav-menu {
    display: flex;
    gap: 20px;
    align-items: center;
    flex-wrap: wrap;
}

.nav-item {
    color: #fff;
    text-decoration: none;
    padding: 10px 15px;
    border-radius: 8px;
    transition: all 0.3s ease;
    font-weight: 500;
    position: relative;
}

.nav-item:hover {
    background: rgba(212, 175, 55, 0.2);
    color: #d4af37;
}

.nav-item.active {
    background: #d4af37;
    color: #1e4a6b;
}

.nav-item.locked {
    color: #777;
    cursor: not-allowed;
    opacity: 0.5;
}

.nav-item.locked::after {
    content: '🔒';
    margin-left: 5px;
}

.main-content {
    max-width: 1200px;
    margin: 40px auto;
    padding: 0 20px;
}

.lesson-section {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    padding: 40px;
    margin-bottom: 40px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    display: none;
}

.lesson-section.active {
    display: block;
    animation: fadeIn 0.8s ease-in;
}

.section-title {
    color: #1e4a6b;
    font-size: 2.5em;
    text-align: center;
    margin-bottom: 30px;
    font-weight: bold;
}

.content-box {
    background: linear-gradient(135deg, #d4af37, #f4d03f);
    color: #1e4a6b;
    padding: 30px;
    border-radius: 15px;
    text-align: center;
    box-shadow: 0 8px 25px rgba(0,0,0,0.2);
    margin-bottom: 30px;
}

.content-box h2 {
    font-size: 1.8em;
    margin-bottom: 20px;
    line-height: 1.3;
}

.content-details {
    background: rgba(212, 175, 55, 0.1);
    padding: 25px;
    border-radius: 10px;
    border-left: 5px solid #d4af37;
    margin-bottom: 30px;
}

.content-details ul {
    list-style: none;
    padding: 0;
}

.content-details li {
    margin: 15px 0;
    padding-left: 20px;
    position: relative;
    line-height: 1.6;
}

.content-details li::before {
    content: '•';
    color: #1e4a6b;
    font-size: 1.5em;
    position: absolute;
    left: 0;
    top: -2px;
}

.text-content {
    line-height: 1.8;
    margin-bottom: 25px;
}

.text-content p {
    margin-bottom: 15px;
    text-align: justify;
}

.text-content strong {
    color: #1e4a6b;
    font-weight: 600;
}

.highlight-box {
    background: linear-gradient(135deg, rgba(212, 175, 55, 0.1), rgba(244, 208, 63, 0.1));
    border: 2px solid #d4af37;
    border-radius: 10px;
    padding: 20px;
    margin: 20px 0;
}

.highlight-title {
    color: #1e4a6b;
    font-size: 1.3em;
    font-weight: bold;
    margin-bottom: 15px;
}

.example-box {
    background: rgba(30, 74, 107, 0.1);
    padding: 20px;
    border-radius: 8px;
    border-left: 4px solid #1e4a6b;
    margin: 15px 0;
}

.example-box p {
    margin: 10px 0;
    line-height: 1.6;
}

.table-container {
    overflow-x: auto;
    margin: 20px 0;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

table th {
    background: #1e4a6b;
    color: white;
    padding: 15px;
    text-align: left;
    font-weight: bold;
}

table td {
    padding: 12px 15px;
    border-bottom: 1px solid #eee;
}

table tr:nth-child(even) {
    background: rgba(212, 175, 55, 0.1);
}

table tr:hover {
    background: rgba(212, 175, 55, 0.2);
}

/* Quiz Styles */
.quiz-container {
    background: rgba(255, 255, 255, 0.98);
    border: 3px solid #d4af37;
    border-radius: 15px;
    padding: 30px;
    margin: 30px 0;
}

.quiz-title {
    color: #1e4a6b;
    font-size: 1.5em;
    font-weight: bold;
    margin-bottom: 20px;
    text-align: center;
}

.quiz-question {
    background: rgba(30, 74, 107, 0.05);
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
}

.question-text {
    color: #1e4a6b;
    font-size: 1.1em;
    font-weight: 600;
    margin-bottom: 15px;
}

.quiz-options {
    list-style: none;
    padding: 0;
}

.quiz-option {
    background: white;
    border: 2px solid #ddd;
    border-radius: 8px;
    padding: 12px 15px;
    margin: 10px 0;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 10px;
}

.quiz-option:hover {
    border-color: #d4af37;
    background: rgba(212, 175, 55, 0.1);
}

.quiz-option.selected {
    border-color: #1e4a6b;
    background: rgba(30, 74, 107, 0.1);
}

.quiz-option.correct {
    border-color: #4caf50;
    background: rgba(76, 175, 80, 0.1);
}

.quiz-option.incorrect {
    border-color: #f44336;
    background: rgba(244, 67, 54, 0.1);
}

.quiz-option input[type="radio"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.quiz-submit {
    background: #1e4a6b;
    color: white;
    border: none;
    padding: 12px 30px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: block;
    margin: 20px auto 0;
}

.quiz-submit:hover {
    background: #2c5d7a;
    transform: translateY(-2px);
}

.quiz-submit:disabled {
    background: #ccc;
    cursor: not-allowed;
    transform: none;
}

.quiz-result {
    margin-top: 20px;
    padding: 15px;
    border-radius: 8px;
    text-align: center;
    font-weight: 600;
    display: none;
}

.quiz-result.success {
    background: rgba(76, 175, 80, 0.2);
    border: 2px solid #4caf50;
    color: #2e7d32;
    display: block;
}

.quiz-result.error {
    background: rgba(244, 67, 54, 0.2);
    border: 2px solid #f44336;
    color: #c62828;
    display: block;
}

/* Audio Player Styles */
.audio-player {
    background: #1e4a6b;
    border-radius: 10px;
    padding: 20px;
    margin: 20px 0;
    text-align: center;
}

.audio-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-top: 15px;
}

.play-btn {
    background: #d4af37;
    color: #1e4a6b;
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    font-size: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.play-btn:hover {
    background: #f4d03f;
    transform: scale(1.1);
}

.audio-progress {
    flex: 1;
    height: 8px;
    background: rgba(212, 175, 55, 0.3);
    border-radius: 4px;
    overflow: hidden;
    cursor: pointer;
    position: relative;
}

.progress-bar {
    height: 100%;
    background: #d4af37;
    width: 0%;
    transition: width 0.1s ease;
}

.time-display {
    color: #d4af37;
    font-size: 14px;
    font-weight: 500;
}

/* Navigation Buttons */
.navigation-buttons {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 30px;
    padding: 20px 0;
}

.nav-button {
    background: #1e4a6b;
    color: white;
    border: none;
    padding: 12px 25px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 500;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-button:hover {
    background: #2c5d7a;
    transform: translateY(-2px);
}

.nav-button:disabled {
    background: #ccc;
    cursor: not-allowed;
    transform: none;
}

.progress-indicator {
    text-align: center;
    color: #666;
    font-size: 14px;
}

/* Footer */
.footer {
    background: #1e4a6b;
    color: white;
    text-align: center;
    padding: 30px 0;
    margin-top: 60px;
}

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

/* Utility Classes */
.red-text {
    color: #d32f2f;
    font-weight: bold;
}

.blue-text {
    color: #1e4a6b;
    font-weight: bold;
}

.green-text {
    color: #388e3c;
    font-weight: bold;
}

.purple-text {
    color: #7b1fa2;
    font-weight: bold;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.8s ease-in;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
    }

    .nav-menu {
        flex-wrap: wrap;
        gap: 10px;
        justify-content: center;
    }

    .nav-item {
        padding: 8px 12px;
        font-size: 14px;
    }

    .section-title {
        font-size: 2em;
    }

    .lesson-section {
        padding: 20px;
    }

    .content-box h2 {
        font-size: 1.4em;
    }

    table {
        font-size: 14px;
    }

    table th,
    table td {
        padding: 10px 8px;
    }
}

/* Hero Section for Index */
.hero-section {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    padding: 40px;
    margin-bottom: 40px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

.hero-title {
    color: #1e4a6b;
    font-size: 2.5em;
    text-align: center;
    margin-bottom: 30px;
    font-weight: bold;
}

.flags-container {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 30px;
    margin: 30px 0;
}

.flag-placeholder {
    width: 150px;
    height: 100px;
    border: 3px dashed #d4af37;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #1e4a6b;
    font-weight: 600;
    background: rgba(212, 175, 55, 0.1);
}

.vs-text {
    font-size: 2em;
    color: #d4af37;
    font-weight: bold;
}

/* Classes Grid for Index */
.classes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

.class-card {
    background: linear-gradient(135deg, #1e4a6b, #2c5d7a);
    color: white;
    padding: 25px;
    border-radius: 12px;
    text-decoration: none;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
    display: block;
}

.class-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(212, 175, 55, 0.3), transparent);
    transition: left 0.5s ease;
}

.class-card:hover::before {
    left: 100%;
}

.class-card:hover {
    transform: translateY(-5px);
    border-color: #d4af37;
    box-shadow: 0 15px 35px rgba(0,0,0,0.3);
}

.class-number {
    background: #d4af37;
    color: #1e4a6b;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    margin-bottom: 15px;
    font-size: 1.3em;
}

.class-title {
    font-size: 1.3em;
    font-weight: bold;
    margin-bottom: 10px;
}

.class-description {
    font-size: 0.95em;
    opacity: 0.9;
    line-height: 1.5;
}

/* Clarifying Box - Caixa de esclarecimento */
.clarifying-box {
    background: linear-gradient(135deg, rgba(103, 58, 183, 0.1), rgba(156, 39, 176, 0.1));
    border: 2px solid #7b1fa2;
    border-radius: 10px;
    padding: 20px;
    margin: 20px 0;
    line-height: 1.8;
}

.clarifying-box p {
    margin: 0;
    color: #4a148c;
    font-weight: 500;
}

/* Table Container - Melhoria para tabelas */
.table {
    margin: 25px 0;
}

.table table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.table table th {
    background: #1e4a6b;
    color: white;
    padding: 18px 15px;
    text-align: left;
    font-weight: bold;
    font-size: 1.05em;
}

.table table td {
    padding: 15px;
    border-bottom: 1px solid #eee;
    line-height: 1.6;
}

.table table tr:last-child td {
    border-bottom: none;
}

.table table tr:nth-child(even) {
    background: rgba(212, 175, 55, 0.05);
}

.table table tr:hover {
    background: rgba(212, 175, 55, 0.15);
}

.table table td:first-child {
    font-weight: 600;
    color: #1e4a6b;
}

.observation-box {
    background: linear-gradient(135deg, rgba(255, 193, 7, 0.1), rgba(255, 235, 59, 0.1));
    border: 2px solid #ffa726;
    border-left: 6px solid #ff9800;
    border-radius: 12px;
    padding: 25px;
    margin: 25px 0;
    box-shadow: 0 4px 15px rgba(255, 152, 0, 0.15);
    position: relative;
    overflow: hidden;
}

.observation-box::before {
    content: '';
    position: absolute;
    top: -2px;
    left: -2px;
    right: -2px;
    bottom: -2px;
    background: linear-gradient(45deg, #ff9800, #ffc107, #ff9800);
    border-radius: 12px;
    z-index: -1;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.observation-box:hover::before {
    opacity: 0.1;
}

.observation-box .observation-title {
    color: #e65100;
    font-size: 1.3em;
    font-weight: bold;
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.observation-box .observation-title::before {
    content: '💡';
    font-size: 1.2em;
}

.observation-box p {
    color: #5d4037;
    line-height: 1.8;
    margin-bottom: 10px;
}

.observation-box p:last-child {
    margin-bottom: 0;
}

.observation-box ul {
    margin: 15px 0;
    padding-left: 25px;
}

.observation-box ul li {
    color: #5d4037;
    line-height: 1.8;
    margin: 10px 0;
}

.observation-box strong {
    color: #e65100;
    font-weight: 600;
}

.observation-box em {
    color: #f57c00;
    font-style: italic;
}

/* Variante alternativa com ícone diferente */
.observation-box.warning {
    background: linear-gradient(135deg, rgba(244, 67, 54, 0.1), rgba(255, 87, 34, 0.1));
    border-color: #ff7043;
    border-left-color: #f44336;
}

.observation-box.warning .observation-title {
    color: #c62828;
}

.observation-box.warning .observation-title::before {
    content: '⚠️';
}

/* Variante para informação */
.observation-box.info {
    background: linear-gradient(135deg, rgba(33, 150, 243, 0.1), rgba(100, 181, 246, 0.1));
    border-color: #64b5f6;
    border-left-color: #2196f3;
}

.observation-box.info .observation-title {
    color: #1565c0;
}

.observation-box.info .observation-title::before {
    content: 'ℹ️';
}

/* Variante para sucesso */
.observation-box.success {
    background: linear-gradient(135deg, rgba(76, 175, 80, 0.1), rgba(129, 199, 132, 0.1));
    border-color: #81c784;
    border-left-color: #4caf50;
}

.observation-box.success .observation-title {
    color: #2e7d32;
}

.observation-box.success .observation-title::before {
    content: '✅';
}