:root {
    --text: #111;
    --muted: #666;
    --bg: #ffffff;
    --border: #eaeaea;
}

body {
    font-family:
        -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Inter, sans-serif;
    margin: 0;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
}

.container {
    max-width: 820px;
    margin: 0 auto;
    padding: 60px 20px;
}

.logo {
    text-align: center;
    font-size: 64px;
    font-weight: 800;
    letter-spacing: 8px;
    margin-bottom: 30px;
}

nav {
    text-align: center;
    margin-bottom: 60px;
}

nav a {
    margin: 0 20px;
    text-decoration: none;
    color: var(--muted);
    font-weight: 500;
}

nav a:hover {
    color: var(--text);
}

h1 {
    font-size: 32px;
    margin-bottom: 20px;
}

h2 {
    margin-top: 40px;
}

blockquote {
    border-left: 3px solid var(--border);
    padding-left: 15px;
    color: var(--muted);
    font-style: italic;
}

.references {
    font-size: 14px;
    color: var(--muted);
}

.calculator {
    margin-top: 40px;
    padding: 30px;
    border: 1px solid var(--border);
    background: #fafafa;
}

input {
    width: 100%;
    padding: 12px;
    font-size: 16px;
    margin-bottom: 15px;
    border: 1px solid var(--border);
}

button {
    padding: 12px 20px;
    background: #111;
    color: white;
    border: none;
    cursor: pointer;
}

button:hover {
    opacity: 0.9;
}

.result {
    margin-top: 20px;
    font-weight: 500;
}

footer {
    text-align: center;
    font-size: 14px;
    color: var(--muted);
    padding: 40px 0;
    border-top: 1px solid var(--border);
    margin-top: 80px;
}

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