/* -----------------------------------------------------------
   Base Theme (Auto Light/Dark)
   ----------------------------------------------------------- */

:root {
    --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

    /* Light mode colours */
    --bg: #ffffff;
    --text: #222222;
    --accent: #004c99;
    --border: #dddddd;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #1a1a1a;
        --text: #e6e6e6;
        --accent: #66aaff;
        --border: #333333;
    }
}

/* -----------------------------------------------------------
   Global Layout
   ----------------------------------------------------------- */

body {
    margin: 0;
    padding: 0;
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-body);
    line-height: 1.6;
    font-size: 18px;
}

main {
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
}

h1, h2, h3 {
    color: var(--text);
    margin-top: 1.4em;
}

p, ul {
    margin-bottom: 1.2em;
}

ul {
    padding-left: 20px;
}

hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: 40px 0;
}

/* -----------------------------------------------------------
   Header + Logo
   ----------------------------------------------------------- */

.site-header {
    display: flex;
    align-items: center;
    padding: 15px 20px;
    border-bottom: 1px solid var(--border);
}

.logo-link {
    text-decoration: none;
}

.logo-large {
    height: 60px;
    display: block;
}

.logo-small {
    height: 40px;
    display: none;
}

/* Mobile: use small.gif */
@media (max-width: 600px) {
    .logo-large {
        display: none;
    }
    .logo-small {
        display: block;
    }
}

/* -----------------------------------------------------------
   Footer
   ----------------------------------------------------------- */

footer {
    text-align: center;
    padding: 30px 0;
    margin-top: 40px;
    border-top: 1px solid var(--border);
    font-size: 14px;
    opacity: 0.8;
}

/* -----------------------------------------------------------
   Links
   ----------------------------------------------------------- */

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

a:hover {
    text-decoration: underline;
}