:root {
    --bg: #ffffff;
    --card: #ffffff;
    --ink: #1d262c;
    --muted: #5c6770;
    --accent: #0f766e;
    --border: #d7d2c7;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Trebuchet MS", "Segoe UI", sans-serif;
    color: var(--ink);
    background: radial-gradient(circle at top, #ffffff 0%, var(--bg) 45%);
}

.page-shell {
    min-height: 100vh;
    max-width: 1200px;
    margin: 0 auto;
    padding: 1.25rem;
}

.site-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.site-title {
    text-decoration: none;
    color: var(--ink);
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.site-nav {
    display: flex;
    gap: 0.9rem;
}

.site-nav a {
    color: var(--muted);
    text-decoration: none;
    padding-bottom: 0.2rem;
    border-bottom: 2px solid transparent;
}

.site-nav a[aria-current="page"] {
    color: var(--accent);
    border-bottom-color: var(--accent);
}

.content {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 1.4rem;
}

.hero h1,
.stack h1 {
    margin-top: 0;
}

.site-footer {
    margin-top: 1rem;
    color: var(--muted);
    font-size: 0.9rem;
}

@media (max-width: 640px) {
    .site-header {
        flex-direction: column;
        align-items: flex-start;
    }
}