/* ==========================================================================
   Umbra — a dark, monospaced theme for Counterglow.
   Terminal typography, a sticky sidebar, dense information design.
   Built for documentation, changelogs and developer writing.
   ========================================================================== */

@layer reset, tokens, base, layout, components, utilities;

@layer reset {
  *, *::before, *::after { box-sizing: border-box; }
  * { margin: 0; }
  html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 5rem; }
  @media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
  }
  img, svg, video, iframe { display: block; max-width: 100%; height: auto; }
  input, button, textarea, select { font: inherit; color: inherit; }
  button { cursor: pointer; background: none; border: 0; }
  :focus-visible { outline: 1px solid var(--accent); outline-offset: 3px; }
}

@layer tokens {
  :root {
    color-scheme: dark;

    --font-mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code", "Fira Code", Menlo, monospace;
    --font-body: var(--font-mono);

    --accent: oklch(0.82 0.17 155);        /* phosphor green */
    --accent-2: oklch(0.75 0.14 220);

    --bg: oklch(0.15 0.011 250);
    --bg-2: oklch(0.19 0.013 250);
    --bg-3: oklch(0.23 0.015 250);
    --line: oklch(0.3 0.015 250);
    --fg: oklch(0.9 0.008 250);
    --fg-dim: oklch(0.63 0.012 250);

    --gutter: clamp(1rem, 4vw, 2.5rem);
    --sidebar: 15rem;
    --measure: 40rem;
    --ease: cubic-bezier(0.32, 0.72, 0, 1);

    --step--1: 0.79rem;
    --step-0: 0.9rem;
    --step-1: clamp(1.05rem, 1rem + 0.25vw, 1.2rem);
    --step-2: clamp(1.3rem, 1.15rem + 0.7vw, 1.75rem);
    --step-3: clamp(1.7rem, 1.35rem + 1.6vw, 2.8rem);
  }

  /* Umbra is a dark theme on purpose, but respects an explicit light choice */
  :root[data-theme="light"] {
    color-scheme: light;
    --bg: oklch(0.985 0.004 250);
    --bg-2: oklch(0.955 0.006 250);
    --bg-3: oklch(0.92 0.008 250);
    --line: oklch(0.86 0.01 250);
    --fg: oklch(0.22 0.012 250);
    --fg-dim: oklch(0.48 0.012 250);
    --accent: oklch(0.5 0.15 155);
    --accent-2: oklch(0.5 0.14 240);
  }
}

@layer base {
  body {
    font-family: var(--font-body);
    font-size: var(--step-0);
    line-height: 1.65;
    color: var(--fg);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
    /* faint scanline texture — subtle enough to stay readable */
    background-image: repeating-linear-gradient(
      to bottom,
      transparent 0 3px,
      color-mix(in oklab, var(--fg) 2%, transparent) 3px 4px
    );
  }
  h1, h2, h3, h4 { font-weight: 700; line-height: 1.2; letter-spacing: -0.01em; text-wrap: balance; }
  a { color: inherit; text-underline-offset: 0.2em; }
  ::selection { background: color-mix(in oklab, var(--accent) 35%, transparent); }
  hr { border: 0; height: 1px; background: var(--line); }
}

@layer layout {
  /* Mobile first: one column, sidebar in the flow. The two-column layout and
     the sticky sidebar only switch on once there is room for them. */
  .wrap { display: grid; grid-template-columns: minmax(0, 1fr); gap: clamp(1.5rem, 4vw, 3.5rem); }
  .wrap > * { min-width: 0; }
  .container { width: min(100% - var(--gutter) * 2, 78rem); margin-inline: auto; }
  @media (min-width: 56rem) {
    .wrap { grid-template-columns: var(--sidebar) minmax(0, 1fr); }
  }
  .section { padding-block: clamp(2rem, 5vw, 3.5rem); }
}

@layer components {
  /* --- top bar ----------------------------------------------------------- */
  .bar {
    position: sticky; top: 0; z-index: 30;
    border-bottom: 1px solid var(--line);
    background: color-mix(in oklab, var(--bg) 88%, transparent);
    backdrop-filter: blur(10px);
  }
  .bar__inner { display: flex; align-items: center; gap: 1rem; padding-block: 0.75rem; }
  .logo { display: inline-flex; align-items: center; gap: 0.5rem; text-decoration: none; font-weight: 700; }
  .logo__prompt { color: var(--accent); }
  .logo__caret {
    display: inline-block; width: 0.55em; height: 1.05em; background: var(--accent);
    translate: 0 0.16em; animation: blink 1.15s steps(2, start) infinite;
  }
  @keyframes blink { 50% { opacity: 0; } }
  @media (prefers-reduced-motion: reduce) { .logo__caret { animation: none; } }

  .bar nav { display: flex; gap: 0.35rem; margin-left: auto; align-items: center; flex-wrap: wrap; }
  .bar nav a {
    padding: 0.25rem 0.6rem; text-decoration: none; color: var(--fg-dim); font-size: var(--step--1);
    border: 1px solid transparent;
  }
  .bar nav a::before { content: "/"; color: var(--line); margin-right: 0.15rem; }
  .bar nav a:hover { color: var(--fg); border-color: var(--line); background: var(--bg-2); }
  .bar nav a[aria-current="page"] { color: var(--accent); border-color: color-mix(in oklab, var(--accent) 40%, transparent); }
  .icon-btn { display: grid; place-items: center; width: 1.9rem; height: 1.9rem; color: var(--fg-dim); border: 1px solid transparent; }
  .icon-btn:hover { color: var(--fg); border-color: var(--line); background: var(--bg-2); }

  /* --- sidebar ----------------------------------------------------------- */
  .sidebar { padding-block: 2rem; }
  @media (min-width: 56rem) {
    .sidebar { position: sticky; top: 4rem; height: calc(100dvh - 5rem); overflow-y: auto; }
  }
  .sidebar h2 {
    font-size: var(--step--1); color: var(--fg-dim); letter-spacing: 0.12em;
    text-transform: uppercase; margin-bottom: 0.6rem;
  }
  .sidebar ul { list-style: none; padding: 0; display: grid; gap: 0.1rem; margin-bottom: 1.75rem; }
  .sidebar a {
    display: block; padding: 0.25rem 0.6rem; text-decoration: none;
    color: var(--fg-dim); font-size: var(--step--1); border-left: 2px solid var(--line);
  }
  .sidebar a:hover { color: var(--fg); background: var(--bg-2); border-left-color: var(--fg-dim); }
  .sidebar a.is-current { color: var(--accent); border-left-color: var(--accent); background: var(--bg-2); }

  /* --- hero -------------------------------------------------------------- */
  .hero { padding-block: clamp(2.5rem, 7vw, 5rem) clamp(1.5rem, 4vw, 3rem); }
  .hero h1 { font-size: var(--step-3); }
  .hero .lead { color: var(--fg-dim); font-size: var(--step-1); max-width: var(--measure); margin-top: 1rem; }
  .eyebrow {
    display: inline-block; font-size: var(--step--1); color: var(--accent);
    border: 1px solid color-mix(in oklab, var(--accent) 35%, transparent);
    padding: 0.1rem 0.5rem; margin-bottom: 1rem;
  }
  .eyebrow::before { content: "$ "; opacity: .7; }

  .button {
    display: inline-flex; align-items: center; gap: 0.5rem;
    padding: 0.5rem 1rem; font-size: var(--step--1); font-weight: 700; text-decoration: none;
    color: var(--bg); background: var(--accent); border: 1px solid var(--accent);
    transition: filter .18s;
  }
  .button:hover { filter: brightness(1.12); }
  .button--ghost { background: none; color: var(--fg); border-color: var(--line); }
  .button--ghost:hover { border-color: var(--accent); color: var(--accent); filter: none; }

  /* --- entry list -------------------------------------------------------- */
  .entries { list-style: none; padding: 0; display: grid; }
  .entry { display: grid; gap: 0.3rem; padding-block: 1rem; border-bottom: 1px solid var(--line); }
  @media (min-width: 44rem) { .entry { grid-template-columns: 7rem 1fr; column-gap: 1.5rem; } .entry__meta { grid-row: span 2; } }
  .entry a { text-decoration: none; }
  .entry__title { font-size: var(--step-1); font-weight: 700; }
  .entry__title::before { content: "› "; color: var(--accent); }
  .entry:hover .entry__title { color: var(--accent); }
  .entry__meta { color: var(--fg-dim); font-size: var(--step--1); font-variant-numeric: tabular-nums; }
  .entry__excerpt { color: var(--fg-dim); font-size: var(--step--1); max-width: var(--measure); }

  /* --- cards ------------------------------------------------------------- */
  .cards { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fill, minmax(min(16rem, 100%), 1fr)); }
  .card {
    display: grid; gap: 0.55rem; text-decoration: none; padding: 1rem;
    border: 1px solid var(--line); background: var(--bg-2);
    transition: border-color .2s, transform .25s var(--ease), background .2s;
  }
  .card:hover { border-color: var(--accent); transform: translateY(-2px); background: var(--bg-3); }
  .card__media { overflow: hidden; aspect-ratio: 16 / 10; background: var(--bg-3); margin: -1rem -1rem 0; }
  .card__media img { width: 100%; height: 100%; object-fit: cover; opacity: .85; transition: opacity .3s; }
  .card:hover .card__media img { opacity: 1; }
  .card__title { font-weight: 700; font-size: var(--step-1); }
  .card__excerpt { color: var(--fg-dim); font-size: var(--step--1); }
  .card__meta { color: var(--accent); font-size: var(--step--1); }

  .section-head { display: flex; align-items: baseline; gap: 1rem; margin-bottom: 1.25rem; }
  .section-head h2 { font-size: var(--step--1); color: var(--fg-dim); letter-spacing: 0.12em; text-transform: uppercase; }
  .section-head h2::before { content: "## "; color: var(--accent); }
  .section-head a { margin-left: auto; font-size: var(--step--1); color: var(--fg-dim); text-decoration: none; }
  .section-head a:hover { color: var(--accent); }

  /* --- article ----------------------------------------------------------- */
  .article-head { padding-block: clamp(2rem, 5vw, 3.5rem) 1.5rem; border-bottom: 1px solid var(--line); }
  .article-head h1 { font-size: var(--step-2); }
  .article-meta { display: flex; flex-wrap: wrap; gap: 0.75rem; color: var(--fg-dim); font-size: var(--step--1); margin-top: 0.75rem; }
  .article-cover { margin-block: 1.5rem; border: 1px solid var(--line); }

  .prose { font-size: var(--step-0); line-height: 1.75; padding-block: 1.5rem; }
  .prose > * + * { margin-top: 1.15em; }
  .prose > p, .prose > ul, .prose > ol { max-width: var(--measure); }
  .prose h2, .prose h3 { margin-top: 2.2em; }
  .prose h2 { font-size: var(--step-1); }
  .prose h2::before { content: "## "; color: var(--accent); }
  .prose h3::before { content: "### "; color: var(--accent-2); }
  .prose ul, .prose ol { padding-left: 1.4em; display: grid; gap: 0.3em; }
  .prose li::marker { color: var(--accent); }
  .prose li.task { list-style: none; margin-left: -1.4em; }
  .prose a { color: var(--accent-2); text-decoration: underline; text-decoration-color: color-mix(in oklab, var(--accent-2) 45%, transparent); }
  .prose a:hover { color: var(--accent); }
  .prose strong { color: var(--fg); font-weight: 700; }
  .prose blockquote {
    border-left: 2px solid var(--accent); padding: 0.4rem 0 0.4rem 1rem;
    color: var(--fg-dim); max-width: var(--measure);
  }
  .prose code { background: var(--bg-3); padding: 0.12em 0.35em; border: 1px solid var(--line); font-size: 0.92em; }
  .prose pre {
    background: var(--bg-2); border: 1px solid var(--line); padding: 1rem 1.1rem;
    overflow-x: auto; font-size: var(--step--1); line-height: 1.65; position: relative;
  }
  .prose pre::before {
    content: ""; position: absolute; inset-block-start: 0; inset-inline: 0; height: 2px;
    background: linear-gradient(90deg, var(--accent), var(--accent-2));
  }
  .prose pre code { background: none; border: 0; padding: 0; }
  .prose figure { margin-block: 1.75em; }
  .prose figure img { border: 1px solid var(--line); }
  .prose figcaption { margin-top: 0.5rem; font-size: var(--step--1); color: var(--fg-dim); }
  .prose figcaption::before { content: "// "; color: var(--accent); }
  .prose .callout { border: 1px solid var(--line); border-left: 2px solid var(--accent); background: var(--bg-2); padding: 0.9rem 1.1rem; font-size: var(--step--1); max-width: var(--measure); }
  .prose .callout--warning { border-left-color: oklch(0.8 0.15 85); }
  .prose .callout--important { border-left-color: oklch(0.68 0.2 25); }
  .table-scroll { overflow-x: auto; }
  .prose table { border-collapse: collapse; width: 100%; font-size: var(--step--1); }
  .prose th, .prose td { text-align: left; padding: 0.45rem 0.75rem; border: 1px solid var(--line); }
  .prose th { background: var(--bg-2); color: var(--accent); }
  .gallery { display: grid; grid-template-columns: repeat(var(--cols, 3), 1fr); gap: 0.5rem; margin-block: 1.75em; }
  .gallery img { width: 100%; aspect-ratio: 1; object-fit: cover; border: 1px solid var(--line); }
  .embed { position: relative; aspect-ratio: 16/9; border: 1px solid var(--line); }
  .embed iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
  .file-link { display: inline-flex; gap: .5rem; align-items: baseline; padding: .3rem .7rem; border: 1px solid var(--line); text-decoration: none; font-size: var(--step--1); }
  .file-link::before { content: "↓ "; color: var(--accent); }

  .tag { display: inline-block; padding: 0.05rem 0.45rem; font-size: var(--step--1); text-decoration: none; color: var(--fg-dim); border: 1px solid var(--line); }
  .tag::before { content: "#"; color: var(--accent); }
  .tag:hover { color: var(--accent); border-color: var(--accent); }

  .pager { display: grid; gap: 0.75rem; grid-template-columns: repeat(auto-fit, minmax(min(15rem, 100%), 1fr)); margin-top: 2.5rem; }
  .pager a { display: grid; gap: 0.15rem; padding: 0.85rem 1rem; border: 1px solid var(--line); text-decoration: none; background: var(--bg-2); }
  .pager a:hover { border-color: var(--accent); }
  .pager span { font-size: var(--step--1); color: var(--fg-dim); }
  .pager strong { font-weight: 700; font-size: var(--step-0); }
  .pager .next { text-align: right; }

  /* --- footer ------------------------------------------------------------ */
  .foot { border-top: 1px solid var(--line); margin-top: 3rem; padding-block: 2rem 3rem; color: var(--fg-dim); font-size: var(--step--1); }
  .foot__inner { display: flex; flex-wrap: wrap; gap: 1.5rem; align-items: baseline; }
  .foot a { color: var(--fg-dim); text-decoration: none; }
  .foot a:hover { color: var(--accent); }
  .foot nav { display: flex; gap: 1rem; margin-left: auto; flex-wrap: wrap; }

  dialog.search { width: min(34rem, 92vw); padding: 0; border: 1px solid var(--accent); background: var(--bg); color: var(--fg); margin-top: 12vh; }
  dialog.search::backdrop { background: oklch(0.1 0.01 250 / 0.7); }
  dialog.search input { width: 100%; padding: 0.85rem 1rem; border: 0; border-bottom: 1px solid var(--line); background: none; font-size: var(--step-0); font-family: var(--font-mono); }
  dialog.search input:focus { outline: none; }
  dialog.search ul { list-style: none; margin: 0; padding: 0.3rem; max-height: 58vh; overflow-y: auto; }
  dialog.search a { display: grid; gap: 0.1rem; padding: 0.5rem 0.7rem; text-decoration: none; }
  dialog.search a:hover, dialog.search li.is-active a { background: var(--bg-2); }
  dialog.search .r-title { font-weight: 700; }
  dialog.search .r-title::before { content: "› "; color: var(--accent); }
  dialog.search .r-excerpt { font-size: var(--step--1); color: var(--fg-dim); }
  dialog.search .hint { padding: 1.5rem; text-align: center; color: var(--fg-dim); font-size: var(--step--1); }

  .js .reveal { opacity: 0; transition: opacity .4s var(--ease); }
  .reveal.is-in { opacity: 1; }
  @media (prefers-reduced-motion: reduce) { .reveal { opacity: 1; } }

  /* --- mobile menu ------------------------------------------------------- */
  .nav-toggle { display: inline-flex; flex-direction: column; justify-content: center; gap: 5px; width: 2.5rem; height: 2.5rem; padding: .55rem; margin-left: .1rem; background: none; border: 0; cursor: pointer; color: inherit; }
  .nav-toggle span { display: block; height: 2px; width: 100%; background: currentColor; transition: transform .28s var(--ease, ease), opacity .2s; }
  [data-nav-open] .nav-toggle span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  [data-nav-open] .nav-toggle span:nth-child(2) { opacity: 0; }
  [data-nav-open] .nav-toggle span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
  .menu-links { display: none; }
  [data-nav-open] .menu-links { display: flex; flex-direction: column; align-items: stretch; position: absolute; top: 100%; left: 0; right: 0; z-index: 40; background: var(--bg, var(--surface, Canvas)); border-block: 1px solid var(--line, color-mix(in oklab, currentColor 16%, transparent)); padding: .4rem var(--gutter, 1.25rem) 1rem; }
  [data-nav-open] .menu-links a { padding: .85rem .2rem; font-size: 1.05rem; border-bottom: 1px solid var(--line, color-mix(in oklab, currentColor 12%, transparent)); }
  [data-nav-open] .menu-links a:last-child { border-bottom: 0; }
  @media (min-width: 48rem) {
    .nav-toggle { display: none; }
    .menu-links { display: flex; align-items: center; gap: .25rem; }
    [data-nav-open] .menu-links { position: static; background: none; border: 0; padding: 0; }
    [data-nav-open] .menu-links a { padding: 0; font-size: inherit; border: 0; }
  }

  .skip { position: absolute; left: .5rem; top: -4rem; z-index: 100; padding: .5rem 1rem; background: var(--accent); color: var(--bg); transition: top .2s; }
  .skip:focus { top: .5rem; }
}

@layer utilities {
  .muted { color: var(--fg-dim); }
  .small { font-size: var(--step--1); }
  .sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); }
}