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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    overflow: hidden;
}


.content {
    padding: 40px;
}

section {
    margin-bottom: 50px;
}

h2 {
    color: #667eea;
    font-size: 2em;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 3px solid #667eea;
}

h3 {
    color: #764ba2;
    font-size: 1.5em;
    margin: 30px 0 15px 0;
}

h4 {
    color: #555;
    font-size: 1.2em;
    margin: 20px 0 10px 0;
}

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

ul, ol {
    margin-left: 30px;
    margin-bottom: 20px;
}

li {
    margin-bottom: 10px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin: 30px 0;
}

.feature-card {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 10px;
    border-left: 4px solid #667eea;
    transition: transform 0.3s, box-shadow 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 20px rgba(102, 126, 234, 0.3);
}

.feature-card h4 {
    color: #667eea;
    margin-top: 0;
}

.badge {
    display: inline-block;
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.9em;
    font-weight: bold;
    margin: 5px;
}

.badge-primary {
    background: #667eea;
    color: white;
}

.badge-success {
    background: #28a745;
    color: white;
}

.badge-info {
    background: #17a2b8;
    color: white;
}

.code-block {
    background: #2d2d2d;
    color: #f8f8f2;
    padding: 20px;
    border-radius: 10px;
    overflow-x: auto;
    margin: 20px 0;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
    line-height: 1.5;
}

.code-block code {
    color: #f8f8f2;
}

.code-inline {
    background: #f4f4f4;
    padding: 2px 8px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
    color: #e83e8c;
}

.info-box {
    background: #e7f3ff;
    border-left: 4px solid #2196F3;
    padding: 20px;
    border-radius: 5px;
    margin: 20px 0;
}

.warning-box {
    background: #fff3cd;
    border-left: 4px solid #ffc107;
    padding: 20px;
    border-radius: 5px;
    margin: 20px 0;
}

.success-box {
    background: #d4edda;
    border-left: 4px solid #28a745;
    padding: 20px;
    border-radius: 5px;
    margin: 20px 0;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}

th, td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid #ddd;
}

th {
    background: #667eea;
    color: white;
    font-weight: bold;
}

tr:hover {
    background: #f5f5f5;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin: 30px 0;
}

.stat-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 30px;
    border-radius: 10px;
    text-align: center;
}

.stat-card .number {
    font-size: 2.5em;
    font-weight: bold;
    margin-bottom: 10px;
}

.stat-card .label {
    font-size: 1.1em;
    opacity: 0.9;
}

.toc {
    background: #f8f9fa;
    padding: 30px;
    border-radius: 10px;
    margin: 30px 0;
}

.toc h3 {
    margin-top: 0;
}

.toc ul {
    list-style: none;
    margin-left: 0;
}

.toc li {
    margin: 10px 0;
}

.toc a {
    color: #667eea;
    text-decoration: none;
    font-weight: 500;
}

.toc a:hover {
    text-decoration: underline;
}

/* Sticky Navigation Header */
.top-nav {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    padding: 15px 40px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 2px solid #667eea;
}

.nav-logo {
    font-size: 1.5em;
    font-weight: bold;
    color: #667eea;
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 10px;
}

.nav-links {
    display: flex;
    gap: 25px;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-links a {
    color: #333;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
    padding: 5px 10px;
    border-radius: 5px;
}

.nav-links a:hover,
.nav-links a.active {
    color: #667eea;
    background: #f0f0f0;
}

/* Enhanced Header */
.hero-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 80px 40px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg width="60" height="60" viewBox="0 0 60 60" xmlns="http://www.w3.org/2000/svg"><g fill="none" fill-rule="evenodd"><g fill="%23ffffff" fill-opacity="0.05"><path d="M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z"/></g></g></svg>');
    opacity: 0.3;
}

.hero-header > * {
    position: relative;
    z-index: 1;
}

.hero-header h1 {
    font-size: 3.5em;
    margin-bottom: 15px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
    animation: fadeInDown 0.8s ease-out;
}

.hero-header .subtitle {
    font-size: 1.4em;
    opacity: 0.95;
    margin-bottom: 30px;
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.author-info {
    background: rgba(255,255,255,0.15);
    backdrop-filter: blur(10px);
    padding: 25px 35px;
    border-radius: 15px;
    margin-top: 30px;
    display: inline-block;
    border: 1px solid rgba(255,255,255,0.2);
    animation: fadeInUp 0.8s ease-out 0.4s both;
}

.author-info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    text-align: left;
}

.author-info p {
    margin: 8px 0;
    display: flex;
    align-items: center;
    gap: 8px;
}

.author-info a {
    color: white;
    text-decoration: none;
    transition: opacity 0.3s;
    border-bottom: 1px solid rgba(255,255,255,0.5);
}

.author-info a:hover {
    opacity: 0.8;
    border-bottom-color: white;
}

/* Enhanced Footer */
footer {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    color: white;
    padding: 60px 40px 30px;
    margin-top: 50px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h3 {
    color: #667eea;
    margin-bottom: 20px;
    font-size: 1.3em;
    border-bottom: 2px solid #667eea;
    padding-bottom: 10px;
}

.footer-section ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

.footer-section li {
    margin-bottom: 12px;
}

.footer-section a {
    color: #ccc;
    text-decoration: none;
    transition: color 0.3s, padding-left 0.3s;
    display: inline-block;
}

.footer-section a:hover {
    color: #667eea;
    padding-left: 5px;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 30px;
    text-align: center;
    color: #999;
}

.footer-bottom p {
    margin: 8px 0;
}

.footer-bottom a {
    color: #667eea;
    text-decoration: none;
}

.footer-bottom a:hover {
    text-decoration: underline;
}

.social-links {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-top: 20px;
}

.social-link {
    width: 40px;
    height: 40px;
    background: rgba(102, 126, 234, 0.2);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    text-decoration: none;
    transition: all 0.3s;
}

.social-link:hover {
    background: #667eea;
    transform: translateY(-3px);
}

/* Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    font-size: 20px;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
    transition: all 0.3s;
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
}

/* Scroll Progress Bar */
.scroll-progress {
    position: fixed;
    top: 0;
    left: 0;
    width: 0%;
    height: 4px;
    background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
    z-index: 1001;
    transition: width 0.1s;
}

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

/* Section ID anchors */
section {
    scroll-margin-top: 80px;
}

@media (max-width: 768px) {
    .hero-header h1 {
        font-size: 2.2em;
    }

    .top-nav {
        flex-direction: column;
        gap: 15px;
        padding: 15px 20px;
    }

    .nav-links {
        flex-wrap: wrap;
        gap: 15px;
        justify-content: center;
    }

    .nav-links a {
        font-size: 0.9em;
    }

    .content {
        padding: 20px;
    }

    .feature-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .back-to-top {
        width: 45px;
        height: 45px;
        bottom: 20px;
        right: 20px;
    }
}

.highlight {
    background: #fff3cd;
    padding: 2px 5px;
    border-radius: 3px;
}

/* Print Styles */
@media print {
    .top-nav, .back-to-top, .scroll-progress {
        display: none;
    }
}