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

:root {
    --primary: #8b5cf6;
    --primary-dark: #7c3aed;
    --secondary: #06b6d4;
    --accent: #f59e0b;
    --bg: #0f172a;
    --bg-card: #1e293b;
    --text: #e2e8f0;
    --text-muted: #94a3b8;
    --border: #334155;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

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

/* Header */
header {
    background: linear-gradient(135deg, #1e1b4b 0%, #312e81 100%);
    padding: 60px 0;
    text-align: center;
    border-bottom: 1px solid var(--border);
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    background: linear-gradient(135deg, #a78bfa, #06b6d4);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    color: var(--text-muted);
    font-size: 1.1rem;
}

/* Navigation */
.main-nav {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.main-nav .container {
    display: flex;
    gap: 30px;
    justify-content: center;
    flex-wrap: wrap;
}

.nav-link {
    color: var(--text);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-link:hover {
    color: var(--primary);
}

.nav-link.external {
    color: var(--secondary);
}

/* Hero */
.hero {
    padding: 60px 0;
    text-align: center;
}

.hero h2 {
    font-size: 2rem;
    margin-bottom: 20px;
    color: var(--primary);
}

.hero-content {
    max-width: 700px;
    margin: 0 auto;
}

.hero-content p {
    margin-bottom: 15px;
    color: var(--text-muted);
}

.hero-buttons {
    margin-top: 30px;
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.btn-secondary {
    background: transparent;
    color: var(--primary);
    border: 1px solid var(--primary);
}

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

.btn {
    background: var(--bg-card);
    color: var(--text);
    border: 1px solid var(--border);
    padding: 8px 16px;
    font-size: 0.9rem;
}

.btn:hover {
    border-color: var(--primary);
    color: var(--primary);
}

/* Sections */
.section {
    padding: 60px 0;
    border-top: 1px solid var(--border);
}

.section h2 {
    font-size: 1.8rem;
    margin-bottom: 30px;
    color: var(--primary);
}

/* Plan Grid */
.plan-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
}

.plan-card {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 25px;
    border: 1px solid var(--border);
    transition: transform 0.3s, border-color 0.3s;
}

.plan-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary);
}

.plan-header {
    display: inline-block;
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 15px;
}

.plan-header.month1 {
    background: rgba(139, 92, 246, 0.2);
    color: #a78bfa;
}

.plan-header.month2 {
    background: rgba(6, 182, 212, 0.2);
    color: #22d3ee;
}

.plan-header.month3 {
    background: rgba(245, 158, 11, 0.2);
    color: #fbbf24;
}

.plan-card h3 {
    margin-bottom: 15px;
    font-size: 1.3rem;
}

.plan-card ul {
    list-style: none;
    margin-bottom: 20px;
}

.plan-card li {
    padding: 8px 0;
    color: var(--text-muted);
    border-bottom: 1px solid var(--border);
}

.plan-card li:last-child {
    border-bottom: none;
}

/* Categories */
.category {
    margin-bottom: 50px;
}

.category h3 {
    font-size: 1.4rem;
    margin-bottom: 20px;
    color: var(--secondary);
}

/* Book Grid */
.book-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
}

.book-card {
    background: var(--bg-card);
    border-radius: 10px;
    padding: 20px;
    border: 1px solid var(--border);
    transition: all 0.3s;
}

.book-card:hover {
    border-color: var(--primary);
    transform: translateY(-3px);
}

.book-card h4 {
    margin-bottom: 10px;
    color: var(--text);
}

.book-card p {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 15px;
}

/* Tools Grid */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
}

.tool-card {
    background: var(--bg-card);
    border-radius: 10px;
    padding: 25px;
    border: 1px solid var(--border);
    text-align: center;
    transition: all 0.3s;
}

.tool-card:hover {
    border-color: var(--secondary);
    transform: translateY(-3px);
}

.tool-card h4 {
    font-size: 1.2rem;
    margin-bottom: 10px;
}

.tool-card p {
    color: var(--text-muted);
    margin-bottom: 15px;
}

/* Progress */
.progress-card {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 30px;
    border: 1px solid var(--border);
    max-width: 500px;
}

.progress-card p {
    margin-bottom: 10px;
}

.progress-bar {
    background: var(--border);
    border-radius: 10px;
    height: 20px;
    overflow: hidden;
    margin: 15px 0;
}

.progress-fill {
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    height: 100%;
    border-radius: 10px;
    transition: width 0.5s;
}

.progress-text {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Footer */
footer {
    background: var(--bg-card);
    padding: 30px 0;
    text-align: center;
    border-top: 1px solid var(--border);
    margin-top: 60px;
}

footer p {
    color: var(--text-muted);
    margin-bottom: 10px;
}

footer a {
    color: var(--primary);
    text-decoration: none;
}

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

/* Content Pages */
.content-page {
    padding: 40px 0;
}

.content-page h1 {
    font-size: 2rem;
    margin-bottom: 30px;
    color: var(--primary);
}

.content-page h2 {
    font-size: 1.5rem;
    margin: 30px 0 15px;
    color: var(--secondary);
}

.content-page h3 {
    font-size: 1.2rem;
    margin: 20px 0 10px;
    color: var(--text);
}

.content-page p {
    margin-bottom: 15px;
    color: var(--text-muted);
}

.content-page ul, .content-page ol {
    margin: 15px 0;
    padding-left: 30px;
}

.content-page li {
    margin-bottom: 8px;
    color: var(--text-muted);
}

.content-page pre {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 15px;
    overflow-x: auto;
    margin: 15px 0;
}

.content-page code {
    font-family: 'Fira Code', monospace;
}

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

.content-page th, .content-page td {
    border: 1px solid var(--border);
    padding: 12px;
    text-align: left;
}

.content-page th {
    background: var(--bg);
    color: var(--primary);
}

.back-link {
    display: inline-block;
    margin-bottom: 20px;
    color: var(--primary);
    text-decoration: none;
}

.back-link:hover {
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.8rem;
    }
    
    .section {
        padding: 40px 0;
    }
    
    .plan-grid, .book-grid, .tools-grid {
        grid-template-columns: 1fr;
    }
    
    .main-nav .container {
        gap: 15px;
    }
}