/* ============================================================================
   ROOT & CUSTOM PROPERTIES
   ========================================================================== */
:root {
    /* Font stacks */
    --mono-font: ui-monospace, "SF Mono", "Cascadia Code", "Segoe UI Mono", "Roboto Mono", "Liberation Mono", "Noto Sans Mono", Menlo, monospace;
    --sans-font: ui-sans-serif, "SF Pro Text", "Segoe UI", "Open Sans", Roboto, "Liberation Sans", "Noto Sans", sans-serif;

    /* Light theme (default fallback) */
    --bg-body: #f2f2f2;
    --color-body: #000;
    --bg-strong: #f1f1f1;
    --color-strong: #000;
    --border-fullscreen: #000;
    --nav-link-bg: #3a3a3a;
    --nav-link-text: #fdfdfd;

    font-size: clamp(0.875rem, calc(0.875rem + ((1vw - 0.1rem) * 0.7328)), 3rem);
}

/* ── Dark Theme (override) ──────────────────────────────────────────── */
@media screen and (prefers-color-scheme: dark) {
    :root {
        --bg-body: #2f2f2f;
        --color-body: #fdfdfd;
        --bg-strong: #1f1f1f;
        --color-strong: #fdfdfd;
        --border-fullscreen: #fff;
        --nav-link-bg: #4a4a4a;
    }
}

/* ============================================================================
   RESET
   ========================================================================== */
*,
*::after,
*::before {
    box-sizing: inherit;
}

html {
    box-sizing: border-box;
    overscroll-behavior: none;
    text-rendering: optimizeLegibility;
}

body {
    background: var(--bg-body);
    color: var(--color-body);
    font: 300 1.3rem/2.6 var(--sans-font);
    min-height: 100dvh;
    margin: 0;
}

/* ============================================================================
   TYPOGRAPHY
   ========================================================================== */
h1,
h2,
h3 {
    font-family: var(--sans-font);
    font-weight: 200;
}

h1 {
    font-size: clamp(1.3rem, calc(1rem + 3vmin), 3rem);
    margin: 3vmin 0 2vmin;
}

h2 {
    font-size: clamp(1.1rem, calc(1rem + 2vmin), 2.5rem);
    margin: 2vmin 0 1.5vmin;
}

h3 {
    font-size: calc(1rem + 2vmin);
    margin: 2vmin 0 1vmin;
}

p {
    clear: both;
    text-align: left;
    text-indent: 0.125rem;
}

main p {
    white-space: pre-line;
}

.tagline {
    font-family: var(--mono-font);
    text-align: center;
    font-weight: 500;
    letter-spacing: 0.05em;
    margin: 1rem 0;
}

/* ============================================================================
   LINKS
   ========================================================================== */
a {
    color: #900;
    text-decoration: none;
}
a:hover {
    text-decoration: underline;
}
a:focus-visible {
    outline: 2px solid #c00;
    outline-offset: 2px;
}

a strong {
    color: inherit;
}

/* ============================================================================
   STRONG (HIGHLIGHT EFFECT)
   ========================================================================== */
strong {
    background: var(--bg-strong);
    color: var(--color-strong);
    font-weight: 600;
    position: relative;
}

strong::before {
    background: #6a6a6a;
    content: "";
    height: 102%;
    left: 0;
    opacity: 0.3;
    padding: 0.15rem;
    position: absolute;
    top: 0;
    transform: skewX(1.65deg) rotate(-1.15deg);
    width: 102%;
    z-index: -1;
}
strong:last-of-type {
    transform: skewX(-1.25deg) rotate(1.45deg);
}

/* ============================================================================
   NAVIGATION
   ========================================================================== */
nav {
    margin: 1rem 0;
}

nav ol,
nav ul {
    display: flex;
    flex-wrap: wrap;
    gap: 0.25rem;
    overflow-x: auto;
    padding: 0.5rem 0;
    margin: 0;
    padding-inline-start: 0;
    list-style: none;
}

nav li {
    display: inline-flex;
    line-height: 2.6;
    white-space: nowrap;
}

nav li a {
    background: var(--nav-link-bg);
    border: 1px outset #333;
    border-radius: 0.2rem;
    font: 300 1.2rem var(--sans-font);
    overflow: hidden;
    padding: 0.25rem 0.5rem;
    text-overflow: ellipsis;
    white-space: nowrap;
    display: block;
}

/* Center header nav */
header nav ul {
    justify-content: center;
}

/* TOC nav (inside main) — stack vertically as a reading list */
.toc-nav ul {
    flex-direction: column;
    gap: 0.5rem;
}

.toc-nav li {
    width: 100%;
    white-space: normal;
}

.toc-nav li a {
    width: 100%;
    white-space: normal;
    overflow: visible;
    text-overflow: clip;
}

/* Center footer nav(s) */
footer nav ul {
    justify-content: center;
    margin-top: 2rem;
}

/* ── Visible TOC links ─────────────────────────────────────────────── */
nav a.toc-link {
    color: var(--nav-link-text);
    background: #900;
    border: none;
    font-weight: 500;
    min-width: fit-content;
}
nav a.toc-link:hover {
    background: #b00;
    text-decoration: none;
}

/* ── Distinct "Back to Top" link ───────────────────────────────────── */
nav a.back-link {
    color: var(--nav-link-text);
    background: #222;
    border: 1px solid #555;
    font-weight: 400;
    min-width: fit-content;
}
nav a.back-link:hover {
    background: #333;
    border-color: #777;
    text-decoration: none;
}

/* ── Literature links (monospace book titles) ──────────────────────── */
nav a.literature-link {
    font-family: var(--mono-font);
    font-size: 1.1rem;
    color: #900;
    /* dark red text */
    background: #eee;
    /* very light grey background */
    border: 1px solid #ccc;
    /* subtle border for definition */
}
nav a.literature-link:hover {
    color: #c00;
    background: #e0e0e0;
    text-decoration: underline;
}

/* ── Dark theme override for literature links ──────────────────────── */
@media screen and (prefers-color-scheme: dark) {
    nav a.literature-link {
        color: #c44;
        /* lighter red for readability on dark */
        background: #2a2a2a;
        /* dark grey card background */
        border-color: #444;
    }
    nav a.literature-link:hover {
        color: #e66;
        background: #333;
    }
}

/* ============================================================================
   SPACING
   ========================================================================== */
main {
    max-width: 80ch;
    margin: 0 auto;
    padding: 0 1rem;
}

footer {
    margin-top: 3rem;
    margin-bottom: 6rem;
    padding-top: 2rem;
    padding-bottom: 2rem;
    border-top: 1px solid #ccc;
}
@media screen and (prefers-color-scheme: dark) {
    footer {
        border-top-color: #444;
    }
}

/* ============================================================================
   FULLSCREEN MODE
   ========================================================================== */
@media all and (display-mode: fullscreen) {
    body {
        border: 0.3rem solid var(--border-fullscreen);
        margin: 0;
    }
}

/* ============================================================================
   MOBILE SAFE AREA
   ========================================================================== */
@supports (padding: max(0px)) {
    body {
        padding: max(env(safe-area-inset-top), 1rem) max(env(safe-area-inset-right), 1rem) max(env(safe-area-inset-bottom), 1rem) max(env(safe-area-inset-left), 1rem);
    }
}