:root {
    --primary-color: #1f4e79;
    --primary-dark: #1e3c8c;
    --light-bg: #f5f9ff;
    --border-color: #d1e0f0;
    --highlight-color: #e3eefa;
    --add-color: #e6ffed;
    --add-border: #abf2bc;
    --remove-color: #ffebe9;
    --remove-border: #ffcdd2;
    --gray-bg: #f8f9fa;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
    padding: 20px;
    max-width: 1200px;
    margin: 0 auto;
    transition: var(--transition);
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
    position: relative;
}

h1 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 2.2em;
    font-weight: 700;
}

.subtitle {
    color: #555;
    font-size: 1.1em;
    margin-bottom: 10px;
    font-weight: 400;
}

.breadcrumb {
    margin-bottom: 20px;
    padding: 10px 0;
    border-radius: 4px;
    font-size: 0.95em;
}

.breadcrumb a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

.breadcrumb a:hover {
    text-decoration: underline;
    color: var(--primary-dark);
}

.container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    grid-gap: 25px;
}

.card {
    background: white;
    border-radius: 8px;
    box-shadow: var(--shadow);
    padding: 20px;
    transition: var(--transition);
    height: 100%;
    display: flex;
    flex-direction: column;
    border: 1px solid var(--border-color);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.12);
    border-color: var(--primary-color);
}

.card h2 {
    color: var(--primary-color);
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border-color);
    font-size: 1.2em;
}

.card-content {
    flex-grow: 1;
    margin-bottom: 20px;
}

.card-footer {
    margin-top: auto;
}

.comparison-container {
    display: flex;
    flex-direction: column;
    gap: 24px;
    margin-bottom: 30px;
}

@media (min-width: 768px) {
    .comparison-container {
        flex-direction: row;
    }
}

.comparison-column {
    flex: 1 1 350px;
    min-width: 320px;
    max-width: 600px;
    padding: 20px;
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.comparison-column h2 {
    color: var(--primary-color);
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border-color);
}

.original {
    background-color: var(--light-bg);
}

.modified {
    background-color: white;
}

p {
    margin-bottom: 15px;
    text-align: justify;
    font-size: 1.05em;
    line-height: 1.8;
}

.highlight-add {
    background: #d4f8e8;
    color: #218838;
}

.highlight-remove {
    background: #ffe3e3;
    color: #c82333;
}

.button, .nav-button {
    display: inline-block;
    background-color: var(--primary-color);
    color: white;
    text-decoration: none;
    padding: 12px 18px;
    border-radius: 6px;
    font-weight: 600;
    transition: var(--transition);
    text-align: center;
    border: none;
    cursor: pointer;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.button {
    width: 100%;
}

.button:hover, .nav-button:hover {
    background-color: var(--primary-dark);
    box-shadow: 0 4px 8px rgba(0,0,0,0.15);
    transform: translateY(-2px);
}

.navigation {
    display: flex;
    justify-content: space-between;
    margin-top: 30px;
    gap: 15px;
}

footer {
    margin-top: 40px;
    text-align: center;
    color: #666;
    font-size: 0.9em;
    padding: 20px 0;
    border-top: 1px solid var(--border-color);
}

@media (max-width: 768px) {
    body {
        padding: 15px;
    }
    
    h1 {
        font-size: 1.8em;
    }
    
    .container {
        grid-template-columns: 1fr;
    }
    
    .comparison-column {
        margin-bottom: 20px;
    }
    
    .navigation {
        flex-direction: column;
    }
    
    .nav-button {
        width: 100%;
        margin-bottom: 10px;
    }
}

@media (max-width: 480px) {
    body {
        padding: 10px;
    }
    
    .card, .comparison-column {
        padding: 15px;
    }
    
    h1 {
        font-size: 1.6em;
    }
    
    p {
        font-size: 1em;
        line-height: 1.6;
    }
}

.legend {
    display: flex;
    gap: 24px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 5px;
}

.legend-color {
    width: 24px;
    height: 16px;
    border-radius: 4px;
}

.legend-add {
    background: #d4f8e8;
    border: 1px solid #2ecc40;
}

.legend-remove {
    background: #ffe3e3;
    border: 1px solid #ff4136;
}

.back-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--primary-color);
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    text-decoration: none;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background-color: #0d355d;
}

/* Trang chủ */
.card-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

.card-header {
    background-color: var(--primary-color);
    color: white;
    padding: 15px;
    font-weight: bold;
}

.card-body {
    padding: 15px;
    min-height: 100px;
}

.card-body p {
    color: #666;
}

.card-footer {
    padding: 15px;
    border-top: 1px solid var(--border-color);
    text-align: right;
}

.button {
    display: inline-block;
    background-color: var(--primary-color);
    color: white;
    text-decoration: none;
    padding: 8px 12px;
    border-radius: 4px;
    font-size: 0.9em;
    transition: background-color 0.3s;
}

.button:hover {
    background-color: #0d355d;
}

/* Styles đặc thù cho trang Điều 10 */
body.times-new-roman {
    font-family: 'Times New Roman', serif;
    font-size: 16px;
}

.comparison-container {
    display: flex;
    flex-wrap: wrap;
    gap: 24px;
    justify-content: center;
    margin: 24px 0;
}

.comparison-column {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.07);
    padding: 24px;
    flex: 1 1 350px;
    min-width: 320px;
    max-width: 600px;
}

.highlight-add {
    background: #d4f8e8;
    color: #218838;
    padding: 0 2px;
    border-radius: 2px;
}

.highlight-remove {
    background: #ffe3e3;
    color: #c82333;
    text-decoration: line-through;
    padding: 0 2px;
    border-radius: 2px;
}

@media (max-width: 900px) {
    .comparison-container {
        flex-direction: column;
        gap: 0;
    }
}

/* Thêm CSS cho phần summary trong card */
.summary {
    font-style: italic;
    border-top: 1px solid #eaeaea;
    padding-top: 10px;
    margin-top: 10px;
    color: #555;
}

/* Thêm các style cho phần nguồn tham khảo */
.sources-container {
    background-color: var(--light-bg);
    border-radius: 8px;
    padding: 15px 20px;
    margin: 20px auto;
    max-width: 800px;
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
}

.sources-title {
    color: var(--primary-color);
    font-size: 1em;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.sources-title i {
    color: var(--primary-color);
}

.sources-list {
    list-style-type: none;
}

.source-item {
    margin-bottom: 10px;
    padding: 8px 10px;
    border-radius: 6px;
    background-color: white;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 10px;
}

.source-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 3px 6px rgba(0, 0, 0, 0.1);
}

.source-item i {
    color: #4285F4;
    font-size: 1.1em;
}

.source-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

.source-link:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

@media (max-width: 768px) {
    .sources-container {
        padding: 12px 15px;
    }
    
    .source-item {
        padding: 6px 8px;
    }
}

/* Thêm CSS cho đường link quan trọng */
.important-link-container {
    display: flex;
    align-items: center;
    background-color: #e8f5e9;
    border: 2px solid #66bb6a;
    border-radius: 8px;
    padding: 10px;
    margin: 10px auto;
    max-width: 800px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.important-link-container:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
    border-color: #43a047;
}

.important-link-content {
    flex-grow: 1;
}

.important-link-label {
    display: block;
    font-weight: 600;
    color: #333;
    margin-bottom: 5px;
    font-size: 1em;
}

.important-link {
    color: #2e7d32;
    text-decoration: none;
    font-weight: 600;
    font-size: 1em;
    transition: all 0.2s ease;
    display: inline-block;
    border-bottom: 1px dashed #2e7d32;
    padding-bottom: 2px;
}

.important-link:hover {
    color: #1b5e20;
    border-bottom: 1px solid #1b5e20;
}

@media (max-width: 768px) {
    .important-link-container {
        flex-direction: column;
        text-align: center;
    }
    
    .important-link-icon {
        margin-right: 0;
    }
    
    .important-link {
        font-size: 1em;
    }
}