:root {
    --bg: #1a1a1a; /* page background */
    --card: #222222; /* card surface */
    --accent: #16a34a; /* vibrant forest green */
    --muted: #bdbdbd;
    --text: #f5f5f5;
    --header-height: 68px;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: Inter, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Fixed header */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 28px;
    background: rgba(12,12,12,0.55);
    backdrop-filter: blur(6px);
    border-bottom: 1px solid rgba(255,255,255,0.03);
    z-index: 1000;
}

.brand {
    font-weight: 800;
    font-size: 1.15rem;
    color: var(--accent);
    letter-spacing: 0.2px;
}

nav {
    display: flex;
    gap: 10px;
    align-items: center;
}

nav a {
    color: var(--muted);
    text-decoration: none;
    padding: 8px 14px;
    border-radius: 999px;
    transition: all 180ms ease;
    font-weight: 600;
    display: inline-block;
}

/* Active tab capsule */
nav a.active {
    color: #fff;
    background: rgba(22,163,74,0.16); /* translucent green */
    border: 1px solid rgba(22,163,74,0.22);
    box-shadow: 0 8px 24px rgba(0,0,0,0.45);
}

main {
    max-width: 980px;
    margin: calc(var(--header-height) + 36px) auto 48px;
    padding: 0 20px 40px;
    text-align: center;
}

.hero {
    margin-bottom: 28px;
}

.hero h1 {
    margin: 0;
    font-size: clamp(2.6rem, 5vw, 4.8rem);
    color: #ffffff;
    line-height: 1;
    font-weight: 800;
}

.hero p {
    margin: 14px auto 0;
    max-width: 760px;
    color: #cfcfcf;
    font-size: 1.1rem;
}

.card {
    background: var(--card);
    border-radius: 16px;
    padding: 28px 34px;
    box-shadow: 0 14px 44px rgba(0,0,0,0.45);
    border: 1px solid rgba(255,255,255,0.03);
    display: inline-block;
    text-align: left;
    min-width: 300px;
}

.card h2 {
    margin: 0 0 8px 0;
    color: #fff;
}

.card p {
    color: #e6e6e6;
    line-height: 1.7;
    margin: 8px 0 0;
}

.card a { color: var(--accent); font-weight:600; }
.card a:hover { text-decoration: underline; }

footer {
    text-align: center;
    padding: 22px 20px 48px;
    color: #9a9a9a;
    font-size: 0.92rem;
}

/* Responsive tweaks */
@media (max-width: 640px) {
    nav { gap: 8px; }
    .hero h1 { font-size: 2.4rem; }
    .card { min-width: auto; width: 100%; }
    main { margin-top: calc(var(--header-height) + 20px); }
}