/* ==========================================================================
   universal.css — design tokens + shared chrome (header, footer, burger).
   Loaded first on every page; page-specific styles live in main.css.
   Theme: minimal, content-first, dark by default (dark navy is canonical).
   ========================================================================== */

:root {
    /* --- Colour ----------------------------------------------------------- */
    --bg: #001122;                       /* canonical dark navy */
    --bg-elev: #06182b;                  /* raised surfaces (cards, code) */
    --bg-elev-2: #0b2a44;                /* hover / pill surfaces */
    --text: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.72);
    --text-muted: rgba(255, 255, 255, 0.50);
    --border: rgba(255, 255, 255, 0.12);
    --border-strong: rgba(255, 255, 255, 0.22);
    --accent: #ffe74c;                   /* yellow — link hover, highlights */
    --accent-ink: #001122;               /* text on an accent background */

    /* --- Type ------------------------------------------------------------- */
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
                 Helvetica, Arial, "Apple Color Emoji", sans-serif;
    --font-mono: ui-monospace, "SF Mono", "Cascadia Code", "Fira Code",
                 Menlo, Consolas, monospace;

    /* --- Layout ----------------------------------------------------------- */
    --content-width: 46rem;              /* readable column */
    --gutter: 1.25rem;

    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;

    --transition-fast: 150ms ease;
}

/* --- Reset / base --------------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; -webkit-text-size-adjust: 100%; }

body {
    font-family: var(--font-sans);
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.65;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }

/* Prose-style links: white, underlined, yellow on hover. Chrome links opt out
   via their own rules below. */
a { color: var(--text); text-decoration: underline; text-underline-offset: 0.2em;
    text-decoration-thickness: 1px; transition: color var(--transition-fast); }
a:hover { color: var(--accent); }

::selection { background: var(--accent); color: var(--accent-ink); }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

/* ==========================================================================
   Header
   ========================================================================== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
}

.site-header__inner {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 0.85rem var(--gutter);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.site-header__brand {
    font-size: 1.15rem;
    font-weight: 700;
    letter-spacing: 0.01em;
    color: var(--text);
    text-decoration: none;
    white-space: nowrap;
}
.site-header__brand:hover { color: var(--accent); }

.site-header__nav { display: flex; align-items: center; gap: 1.25rem; }

.site-nav__links {
    display: flex;
    align-items: center;
    gap: 1.25rem;
    list-style: none;
}
.site-nav__links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
}
.site-nav__links a:hover { color: var(--accent); }

.site-header__socials { display: flex; align-items: center; gap: 0.75rem; }
.site-header__socials a { line-height: 0; }
.site-header__socials img {
    width: 1.25rem; height: 1.25rem;
    filter: brightness(0) invert(1);
    opacity: 0.75;
    transition: opacity var(--transition-fast);
}
.site-header__socials a:hover img { opacity: 1; }

/* ==========================================================================
   Burger menu (mobile only)
   ========================================================================== */
.burger-menu { position: relative; display: none; }

.burger-menu__toggle {
    display: flex; align-items: center; justify-content: center;
    background: transparent; border: none; padding: 0; cursor: pointer;
}
.burger-menu__icon {
    width: 1.4rem; height: 1.4rem;
    filter: brightness(0) invert(1); opacity: 0.8;
    transition: opacity var(--transition-fast);
}
.burger-menu__toggle:hover .burger-menu__icon { opacity: 1; }

.burger-menu__dropdown {
    position: absolute;
    top: calc(100% + 0.6rem);
    right: 0;
    min-width: 160px;
    background: var(--bg-elev);
    border: 1px solid var(--border-strong);
    border-radius: var(--radius-md);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.5);
    overflow: hidden;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity var(--transition-fast), transform var(--transition-fast),
                visibility var(--transition-fast);
    z-index: 200;
}
.burger-menu__dropdown.open { opacity: 1; visibility: visible; transform: translateY(0); }

.burger-menu__item {
    display: block;
    padding: 0.7rem 1rem;
    color: var(--text);
    font-size: 0.95rem;
    text-decoration: none;
    border-bottom: 1px solid var(--border);
}
.burger-menu__item:last-child { border-bottom: none; }
.burger-menu__item:hover { background: var(--accent); color: var(--accent-ink); }

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer { margin-top: auto; border-top: 1px solid var(--border); }
.site-footer__inner {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 1.5rem var(--gutter);
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 0.5rem;
    color: var(--text-muted);
    font-size: 0.85rem;
}
.site-footer__counter { color: var(--text-muted); }

/* ==========================================================================
   Responsive: swap desktop links for the burger
   ========================================================================== */
@media (max-width: 640px) {
    .site-nav__links { display: none; }
    .burger-menu { display: block; }
}