:root {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --primary-text: #f8fafc;
    --secondary-text: #94a3b8;
    --accent-color: #38bdf8;
    --donut-pink: #f472b6;
    --tree-green: #4ade80;
    --nav-bg: #1e293b;
    --nav-height: 70px;
    --border-color: #334155;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    margin: 0;
    padding-top: var(--nav-height);
    background-color: var(--bg-color);
    color: var(--primary-text);
    line-height: 1.8;
}

/* Navigation */
nav {
    height: var(--nav-height);
    background: var(--nav-bg);
    position: fixed;
    top: 0; left: 0; width: 100%;
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
    display: flex; justify-content: center;
}

.nav-container {
    width: 100%; max-width: 1000px;
    display: flex; justify-content: space-between; align-items: center; padding: 0 1.5rem;
    position: relative;
}

.logo { font-weight: 800; font-size: 1.4rem; color: var(--accent-color); text-decoration: none; }
.nav-links { display: flex; list-style: none; gap: 2rem; margin: 0; padding: 0; }
.nav-links a { text-decoration: none; color: var(--primary-text); font-weight: 500; transition: 0.3s; }
.nav-links a:hover { color: var(--accent-color); }

/* Hamburger Menu */
.hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; }
.hamburger span { width: 25px; height: 3px; background: var(--primary-text); border-radius: 2px; transition: 0.3s; }

@media (max-width: 768px) {
    .hamburger { display: flex; }
    .nav-links {
        position: absolute; top: var(--nav-height); left: 0; width: 100%;
        flex-direction: column; align-items: center; background: var(--nav-bg);
        max-height: 0; overflow: hidden; transition: max-height 0.4s ease-in-out;
    }
    .nav-links.active { max-height: 500px; border-bottom: 1px solid var(--border-color); }
    .nav-links li { width: 100%; text-align: center; border-top: 1px solid var(--border-color); }
    .nav-links a { display: block; padding: 1.5rem 0; }
    .hamburger.active span:nth-child(1) { transform: translateY(8px) rotate(45deg); }
    .hamburger.active span:nth-child(2) { opacity: 0; }
    .hamburger.active span:nth-child(3) { transform: translateY(-8px) rotate(-45deg); }
}

/* Reusable Components */
.container { max-width: 1000px; margin: 0 auto; padding: 0 1.5rem; }
article, .card { background: var(--card-bg); padding: 2.5rem; border-radius: 12px; border: 1px solid var(--border-color); margin-bottom: 2rem; }
.btn-primary { display: inline-block; background: var(--accent-color); color: var(--bg-color); padding: 0.8rem 1.8rem; border-radius: 50px; font-weight: 800; text-decoration: none; transition: 0.3s; }
.btn-primary:hover { transform: scale(1.05); box-shadow: 0 0 20px rgba(56, 189, 248, 0.4); }

footer { text-align: center; padding: 4rem 0; margin-top: 4rem; border-top: 1px solid var(--border-color); color: var(--secondary-text); }