/* ==========================================================================
   SysAdmin Heaven — design system, layout and components.
   Content typography lives in content.css; code presentation in code.css.
   ========================================================================== */

/* --- Tokens ------------------------------------------------------------- */
:root {
  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "Cascadia Code", "JetBrains Mono", "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --wrap: 1120px;
  --measure: 68ch;

  --step-0: 1rem;
  --step-1: 1.15rem;
  --step-2: 1.4rem;
  --step-3: 1.85rem;
  --step-4: 2.4rem;
  --step-5: clamp(2.4rem, 1.6rem + 3vw, 3.6rem);

  --space-1: .25rem;
  --space-2: .5rem;
  --space-3: .75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4.5rem;

  --radius: 10px;
  --radius-sm: 6px;

  --halo: #F5B932;
  --accent: #8B5CF6;           /* overridden inline from theme config */
  --transition: 160ms ease;
}

/* Dark is the default and the design's primary target. */
:root, [data-scheme="dark"] {
  --bg:            #0B0E14;
  --bg-subtle:     #0F131B;
  --surface:       #141924;
  --surface-2:     #1A2130;
  --border:        #232B3A;
  --border-strong: #313C50;
  --text:          #E6EAF2;
  --text-muted:    #9BA6B9;
  --text-dim:      #6C7789;
  --accent-contrast: #FFFFFF;
  --accent-wash:   color-mix(in srgb, var(--accent) 14%, transparent);
  --shadow:        0 1px 2px rgba(0,0,0,.4), 0 8px 24px -12px rgba(0,0,0,.6);
}

[data-scheme="light"] {
  --bg:            #FCFCFE;
  --bg-subtle:     #F3F5F9;
  --surface:       #FFFFFF;
  --surface-2:     #F7F8FB;
  --border:        #E2E6EF;
  --border-strong: #C9D0DE;
  --text:          #12151C;
  --text-muted:    #545C6D;
  --text-dim:      #6E7686;
  --halo:          #B87C05;
  --accent-contrast: #FFFFFF;
  --accent-wash:   color-mix(in srgb, var(--accent) 10%, transparent);
  --shadow:        0 1px 2px rgba(16,20,30,.05), 0 10px 28px -16px rgba(16,20,30,.25);
}

/* --- Base --------------------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 5.5rem;   /* clears the sticky header on anchor jumps */
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: var(--step-0);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  /* Nothing in an article may push the page sideways. */
  overflow-x: hidden;
}

img, svg, video { max-width: 100%; height: auto; }

a { color: var(--accent); text-underline-offset: .2em; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 3px;
}

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--accent); color: var(--accent-contrast);
  padding: var(--space-3) var(--space-4); border-radius: 0 0 var(--radius) 0;
}
.skip-link:focus { left: 0; }

main:focus { outline: none; }

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--space-5);
}

.section { padding-block: var(--space-7); }
.sep { color: var(--text-dim); margin-inline: .5em; }

/* --- Header ------------------------------------------------------------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 86%, transparent);
  backdrop-filter: saturate(1.6) blur(10px);
  border-bottom: 1px solid var(--border);
}

.site-header__inner {
  display: flex; align-items: center; gap: var(--space-5);
  min-height: 4rem;
}

.brand {
  display: inline-flex; align-items: center; gap: .6rem;
  color: var(--text); text-decoration: none; font-weight: 600;
  margin-inline-end: auto;
}
.brand svg { display: block; height: 30px; width: auto; }
.brand__mark svg { height: 28px; }
.brand__text { font-size: 1.05rem; letter-spacing: -.015em; color: var(--text); white-space: nowrap; }
.brand__text strong { font-weight: 700; }
.brand__text span { font-weight: 400; color: var(--text-muted); }

.site-nav { display: flex; align-items: center; gap: var(--space-5); }
.site-nav__list {
  display: flex; align-items: center; gap: var(--space-5);
  list-style: none; margin: 0; padding: 0;
}
.site-nav__list a {
  color: var(--text-muted); text-decoration: none;
  font-size: .95rem; font-weight: 500;
  padding-block: .4rem;
  border-bottom: 2px solid transparent;
  transition: color var(--transition), border-color var(--transition);
}
.site-nav__list a:hover { color: var(--text); }
.site-nav__list a[aria-current="page"] { color: var(--text); border-bottom-color: var(--accent); }

.scheme-toggle {
  display: grid; place-items: center;
  width: 2.25rem; height: 2.25rem; padding: 0;
  background: transparent; color: var(--text-muted);
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  cursor: pointer; transition: color var(--transition), border-color var(--transition);
}
.scheme-toggle:hover { color: var(--text); border-color: var(--border-strong); }
.scheme-toggle svg {
  width: 18px; height: 18px; grid-area: 1/1;
  fill: none; stroke: currentColor; stroke-width: 1.8;
  stroke-linecap: round; stroke-linejoin: round;
}
[data-scheme="dark"] .icon-sun  { display: block; }
[data-scheme="dark"] .icon-moon { display: none; }
[data-scheme="light"] .icon-sun  { display: none; }
[data-scheme="light"] .icon-moon { display: block; }

.nav-toggle {
  display: none;
  width: 2.4rem; height: 2.4rem; padding: 0;
  background: transparent; border: 1px solid var(--border);
  border-radius: var(--radius-sm); cursor: pointer;
}
.nav-toggle__bar {
  display: block; width: 16px; height: 1.8px; margin: 3.5px auto;
  background: var(--text); border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:first-child { transform: translateY(3px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:last-child  { transform: translateY(-2.5px) rotate(-45deg); }

/* --- Hero --------------------------------------------------------------- */
.hero {
  position: relative;
  border-bottom: 1px solid var(--border);
  background: var(--bg-subtle);
  overflow: hidden;
}
/* A faint engineering grid — present, but never competing with the text. */
.hero::before {
  content: ""; position: absolute; inset: 0;
  background-image:
    linear-gradient(to right, var(--border) 1px, transparent 1px),
    linear-gradient(to bottom, var(--border) 1px, transparent 1px);
  background-size: 64px 64px;
  opacity: .5;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 20%, transparent 75%);
  pointer-events: none;
}
.hero__inner { position: relative; padding-block: var(--space-8) var(--space-7); }

.hero__eyebrow {
  display: inline-flex; align-items: center; gap: .55rem;
  margin: 0 0 var(--space-4);
  font-family: var(--font-mono); font-size: .8rem; letter-spacing: .02em;
  color: var(--text-muted);
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 999px; padding: .35rem .85rem;
}
.status-dot {
  width: 7px; height: 7px; border-radius: 50%;
  background: #3FB950; box-shadow: 0 0 0 3px color-mix(in srgb, #3FB950 20%, transparent);
}
.hero__title {
  margin: 0; font-size: var(--step-5); line-height: 1.05;
  letter-spacing: -.03em; font-weight: 700;
}
.hero__tagline {
  margin: var(--space-3) 0 0;
  font-family: var(--font-mono); font-size: var(--step-1);
  color: var(--accent);
}
.hero__desc {
  margin: var(--space-5) 0 0; max-width: 60ch;
  color: var(--text-muted); font-size: var(--step-1);
}
.hero__actions { margin: var(--space-6) 0 0; display: flex; gap: var(--space-3); flex-wrap: wrap; }

.btn {
  display: inline-block; padding: .7rem 1.3rem;
  border: 1px solid var(--border-strong); border-radius: var(--radius);
  background: var(--surface); color: var(--text);
  font-weight: 600; font-size: .95rem; text-decoration: none;
  transition: border-color var(--transition), background var(--transition), transform var(--transition);
}
.btn:hover { border-color: var(--accent); transform: translateY(-1px); }
.btn--primary {
  background: var(--accent); border-color: var(--accent); color: var(--accent-contrast);
}
.btn--primary:hover { filter: brightness(1.08); }

/* --- Section heads ------------------------------------------------------ */
.section__head {
  display: flex; align-items: baseline; justify-content: space-between;
  gap: var(--space-4); margin-bottom: var(--space-5);
  padding-bottom: var(--space-3); border-bottom: 1px solid var(--border);
}
.section__title {
  margin: 0; font-size: var(--step-2); letter-spacing: -.02em; font-weight: 650;
}
.section__more { font-size: .9rem; text-decoration: none; white-space: nowrap; }
.section__more:hover { text-decoration: underline; }

.page-head { margin-bottom: var(--space-6); }
.page-head__title { margin: 0; font-size: var(--step-4); letter-spacing: -.025em; line-height: 1.15; }
.page-head__subtitle { margin: var(--space-3) 0 0; color: var(--text-muted); font-size: var(--step-1); max-width: var(--measure); }
.page-head__intro { margin-top: var(--space-4); }

/* --- Article cards ------------------------------------------------------ */
.card-list { display: grid; gap: var(--space-2); }

.card {
  position: relative;
  padding: var(--space-5) var(--space-5) var(--space-5) calc(var(--space-5) + 3px);
  border: 1px solid transparent;
  border-radius: var(--radius);
  transition: background var(--transition), border-color var(--transition);
  min-width: 0;
}
.card::before {
  content: ""; position: absolute; left: 0; top: var(--space-5); bottom: var(--space-5);
  width: 2px; border-radius: 2px; background: var(--border-strong);
  transition: background var(--transition);
}
.card:hover { background: var(--surface); border-color: var(--border); }
.card:hover::before { background: var(--accent); }

.card__meta, .meta {
  display: flex; align-items: center; flex-wrap: wrap;
  font-family: var(--font-mono); font-size: .8rem; color: var(--text-dim);
}
.card__title { margin: var(--space-2) 0 0; font-size: var(--step-2); line-height: 1.25; letter-spacing: -.02em; }
.card__title a { color: var(--text); text-decoration: none; }
.card__title a:hover { color: var(--accent); }
.card__subtitle { margin: var(--space-2) 0 0; color: var(--text-muted); font-size: .98rem; }
.card__excerpt {
  margin: var(--space-3) 0 0; color: var(--text-muted);
  max-width: var(--measure); overflow-wrap: anywhere;
}

/* --- Tags --------------------------------------------------------------- */
.tags { display: flex; flex-wrap: wrap; gap: var(--space-2); list-style: none; margin: var(--space-4) 0 0; padding: 0; }
.tag {
  display: inline-block; padding: .2rem .6rem;
  font-family: var(--font-mono); font-size: .76rem;
  color: var(--text-muted); text-decoration: none;
  background: var(--surface-2); border: 1px solid var(--border);
  border-radius: 999px;
  transition: color var(--transition), border-color var(--transition);
}
.tag:hover { color: var(--text); border-color: var(--accent); }
.tag--category { color: var(--accent); border-color: color-mix(in srgb, var(--accent) 35%, var(--border)); }

/* --- Topics ------------------------------------------------------------- */
.topic-grid {
  display: grid; gap: var(--space-2);
  grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
  list-style: none; margin: 0; padding: 0;
}
.topic {
  display: flex; align-items: center; justify-content: space-between; gap: var(--space-3);
  padding: .7rem .95rem;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  color: var(--text); text-decoration: none;
  transition: border-color var(--transition), transform var(--transition);
}
.topic:hover { border-color: var(--accent); transform: translateY(-1px); }
.topic__name { font-weight: 550; font-size: .95rem; overflow-wrap: anywhere; }
.topic__count { font-family: var(--font-mono); font-size: .78rem; color: var(--text-dim); }

/* --- Philosophy --------------------------------------------------------- */
.philosophy {
  padding: var(--space-6);
  background: var(--surface); border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
}
.philosophy__title { margin: 0 0 var(--space-3); font-size: var(--step-2); letter-spacing: -.02em; }
.philosophy p { margin: 0 0 var(--space-3); color: var(--text-muted); max-width: var(--measure); }
.philosophy p:last-child { margin-bottom: 0; }
.philosophy__note { font-size: .93rem; color: var(--text-dim) !important; }

/* --- Blog extras -------------------------------------------------------- */
.filter-notice {
  display: flex; align-items: center; gap: var(--space-3); flex-wrap: wrap;
  padding: .7rem 1rem; margin-bottom: var(--space-5);
  background: var(--accent-wash); border: 1px solid color-mix(in srgb, var(--accent) 30%, var(--border));
  border-radius: var(--radius); font-size: .92rem;
}
.filter-notice__clear { font-family: var(--font-mono); font-size: .82rem; }
.empty-state { color: var(--text-muted); padding: var(--space-6) 0; }

.pagination {
  display: flex; align-items: center; justify-content: space-between; gap: var(--space-4);
  margin-top: var(--space-7); padding-top: var(--space-5);
  border-top: 1px solid var(--border);
  font-size: .92rem;
}
.pagination__step { text-decoration: none; font-weight: 550; }
.pagination__step.is-disabled { color: var(--text-dim); opacity: .5; }
.pagination__count { font-family: var(--font-mono); font-size: .82rem; color: var(--text-dim); }

/* --- Breadcrumbs -------------------------------------------------------- */
.breadcrumbs { padding-top: var(--space-5); }
.breadcrumbs ol {
  display: flex; flex-wrap: wrap; gap: .4rem; list-style: none; margin: 0; padding: 0;
  font-family: var(--font-mono); font-size: .8rem; color: var(--text-dim);
}
.breadcrumbs li + li::before { content: "/"; margin-right: .4rem; color: var(--text-dim); }
.breadcrumbs a { color: var(--text-muted); text-decoration: none; }
.breadcrumbs a:hover { color: var(--accent); }
.breadcrumbs [aria-current="page"] { color: var(--text-muted); }

/* --- Article layout ----------------------------------------------------- */
.article { padding-block: var(--space-6) var(--space-8); }
.article__head { margin-bottom: var(--space-6); }
.article__title {
  margin: 0; font-size: var(--step-4); line-height: 1.13; letter-spacing: -.03em;
  overflow-wrap: break-word;
}
.article__subtitle {
  margin: var(--space-4) 0 0; color: var(--text-muted);
  font-size: var(--step-1); max-width: var(--measure);
}
.article__meta { margin-top: var(--space-4); }
.article__body { max-width: var(--measure); }

.article__foot { margin-top: var(--space-8); padding-top: var(--space-5); border-top: 1px solid var(--border); }

.prev-next { display: grid; gap: var(--space-3); margin-top: var(--space-6); grid-template-columns: 1fr; }
.prev-next__link {
  display: block; padding: var(--space-4);
  border: 1px solid var(--border); border-radius: var(--radius);
  text-decoration: none; color: var(--text); min-width: 0;
  transition: border-color var(--transition);
}
.prev-next__link:hover { border-color: var(--accent); }
.prev-next__link--right { text-align: right; }
.prev-next__dir { display: block; font-family: var(--font-mono); font-size: .76rem; color: var(--text-dim); }
.prev-next__title { display: block; margin-top: .25rem; font-weight: 550; overflow-wrap: anywhere; }

.related { margin-top: var(--space-7); }
.related__title { font-size: var(--step-1); margin: 0 0 var(--space-3); }
.related__list { list-style: none; margin: 0; padding: 0; display: grid; gap: var(--space-2); }
.related__list li {
  display: flex; justify-content: space-between; gap: var(--space-4);
  padding-bottom: var(--space-2); border-bottom: 1px solid var(--border);
}
.related__list a { text-decoration: none; font-weight: 500; }
.related__list a:hover { text-decoration: underline; }
.related__list time { font-family: var(--font-mono); font-size: .78rem; color: var(--text-dim); white-space: nowrap; }

/* --- Table of contents -------------------------------------------------- */
.toc {
  margin-bottom: var(--space-6); padding: var(--space-4) var(--space-5);
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.toc__title {
  margin: 0; font-family: var(--font-mono);
  font-size: .78rem; text-transform: uppercase; letter-spacing: .08em; color: var(--text-dim);
  cursor: pointer; list-style: none;
  display: flex; align-items: center; gap: .5rem;
  padding: .15rem 0;
}
.toc__title::-webkit-details-marker { display: none; }
/* Disclosure triangle, rotated when open. */
.toc__title::before {
  content: ""; width: 0; height: 0; flex: none;
  border-left: 5px solid currentColor;
  border-block: 4px solid transparent;
  transition: transform var(--transition);
}
.toc[open] .toc__title::before { transform: rotate(90deg); }
.toc[open] .toc__title { margin-bottom: var(--space-3); }
.toc__title:hover { color: var(--text); }
.toc__list { list-style: none; margin: 0; padding: 0; display: grid; gap: .35rem; }
.toc__list .toc-h3 { padding-left: var(--space-4); }
.toc__list a {
  color: var(--text-muted); text-decoration: none; font-size: .9rem;
  display: block; padding: .1rem 0; overflow-wrap: anywhere;
  border-left: 2px solid transparent; padding-left: .6rem; margin-left: -.6rem;
}
.toc__list a:hover { color: var(--text); }
.toc__list a.is-active { color: var(--accent); border-left-color: var(--accent); }

/* --- Error page --------------------------------------------------------- */
.error-page { padding-block: var(--space-8); max-width: 46ch; }
.error-page__code {
  margin: 0; font-family: var(--font-mono); font-size: var(--step-5);
  font-weight: 700; color: var(--accent); line-height: 1;
}
.error-page__title { margin: var(--space-4) 0 0; font-size: var(--step-3); letter-spacing: -.02em; }
.error-page__text { color: var(--text-muted); }
.error-page__actions { display: flex; gap: var(--space-3); flex-wrap: wrap; margin-top: var(--space-6); }

/* --- Footer ------------------------------------------------------------- */
.site-footer { margin-top: var(--space-8); border-top: 1px solid var(--border); background: var(--bg-subtle); }
.site-footer__inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: var(--space-4); flex-wrap: wrap; padding-block: var(--space-5);
}
.site-footer__meta { margin: 0; font-size: .87rem; color: var(--text-dim); }
.site-footer__tagline { font-family: var(--font-mono); font-size: .82rem; }
.site-footer__links { display: flex; gap: var(--space-4); flex-wrap: wrap; }
.site-footer__links a { font-size: .87rem; color: var(--text-muted); text-decoration: none; }
.site-footer__links a:hover { color: var(--accent); text-decoration: underline; }

/* --- Responsive --------------------------------------------------------- */
@media (min-width: 1180px) {
  /* Sticky TOC beside the article, once there is genuinely room for it. */
  .article--with-toc {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 15rem;
    grid-template-areas: "head head" "body toc" "foot foot";
    column-gap: var(--space-7);
  }
  .article--with-toc .article__head { grid-area: head; }
  .article--with-toc .article__body { grid-area: body; }
  .article--with-toc .article__foot { grid-area: foot; }
  .article--with-toc .toc {
    grid-area: toc; position: sticky; top: 5.5rem;
    align-self: start; margin-bottom: 0;
    max-height: calc(100vh - 7rem); overflow-y: auto;
    background: transparent; border: 0; border-left: 1px solid var(--border);
    border-radius: 0; padding: 0 0 0 var(--space-4);
  }
  .prev-next { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 760px) {
  .nav-toggle { display: block; }
  .site-nav {
    position: absolute; left: 0; right: 0; top: 100%;
    flex-direction: column; align-items: stretch; gap: 0;
    background: var(--bg); border-bottom: 1px solid var(--border);
    padding: var(--space-3) var(--space-5) var(--space-5);
    display: none;
  }
  .site-nav.is-open { display: flex; }
  .site-nav__list { flex-direction: column; align-items: stretch; gap: 0; }
  .site-nav__list a { display: block; padding: .7rem 0; border-bottom: 1px solid var(--border); }
  .site-nav__list a[aria-current="page"] { border-bottom-color: var(--accent); }
  .scheme-toggle { margin-top: var(--space-4); align-self: flex-start; }

  .site-header__inner { position: relative; }
  .hero__inner { padding-block: var(--space-7) var(--space-6); }
  .section { padding-block: var(--space-6); }
  .card { padding-inline: var(--space-4); }
  .site-footer__inner { flex-direction: column; align-items: flex-start; }
  .brand__text { font-size: .98rem; }
}

/* --- Motion ------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
}

@media print {
  .site-header, .site-footer, .toc, .prev-next, .related, .skip-link { display: none !important; }
  body { background: #fff; color: #000; }
}