:root {
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-main: #f8fafc;
    --text-muted: #cbd5e1;
    --border-color: #334155;
    --accent: #8b5cf6;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    background: rgba(30, 41, 59, 0.8);
    backdrop-filter: blur(10px);
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-decoration: none;
}

nav {
    display: flex;
    gap: 1rem;
}

nav a {
    text-decoration: none;
    color: var(--text-muted);
    font-size: 1rem;
    font-weight: 600;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: all 0.3s ease;
}

nav a:hover {
    color: var(--text-main);
    background: rgba(255, 255, 255, 0.05);
}

nav a.active {
    color: var(--text-main);
    background: var(--primary);
    box-shadow: 0 4px 14px 0 rgba(99, 102, 241, 0.39);
}

main {
    flex: 1;
    max-width: 800px;
    margin: 3rem auto;
    padding: 0 2rem;
    width: 100%;
}

.content-section {
    background: var(--card-bg);
    padding: 2.5rem;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.5);
    animation: fadeIn 0.4s ease-out forwards;
}

h1 {
    font-size: 2.2rem;
    margin-bottom: 1.5rem;
    color: var(--text-main);
    position: relative;
    padding-bottom: 0.5rem;
}

h1::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    height: 3px;
    width: 60px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    border-radius: 3px;
}

h2 {
    font-size: 1.4rem;
    margin: 2rem 0 1rem;
    color: var(--text-main);
}

p {
    margin-bottom: 1rem;
    color: var(--text-muted);
}

ul {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
    color: var(--text-muted);
}

li {
    margin-bottom: 0.5rem;
}

.content-link {
    color: var(--primary);
    text-decoration: none;
    transition: color 0.3s;
}

.content-link:hover {
    color: var(--accent);
    text-decoration: underline;
}

footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
    font-size: 0.9rem;
    border-top: 1px solid var(--border-color);
    margin-top: auto;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@media (max-width: 600px) {
    header {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem;
    }
    main {
        margin: 2rem auto;
        padding: 0 1rem;
    }
    .content-section {
        padding: 1.5rem;
    }
    h1 {
        font-size: 1.8rem;
    }
}