/* ===========================================================
   AI-Augmented Security Auditing — site styles
   Dark minimalist technical-docs theme
   =========================================================== */

:root {
  --bg:            #0d1117;
  --bg-elev:       #161b22;
  --bg-code:       #0a0e14;
  --border:        #21262d;
  --border-soft:   #1a1f26;
  --text:          #e6edf3;
  --text-muted:    #8b949e;
  --text-dim:      #6e7681;
  --accent:        #58a6ff;
  --accent-soft:   #1f6feb33;
  --warn:          #d29922;
  --warn-soft:     #d2992222;
  --danger:        #f85149;
  --danger-soft:   #f8514922;
  --ok:            #3fb950;
  --ok-soft:       #3fb95022;
  --kbd-bg:        #21262d;
  --selection:     #1f6feb55;

  --radius-sm: 4px;
  --radius:    6px;
  --radius-lg: 10px;

  --sidebar-w: 280px;
  --content-max: 760px;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Inter",
               "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection { background: var(--selection); }

/* ===========================================================
   Layout
   =========================================================== */

.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  background: var(--bg-elev);
  border-right: 1px solid var(--border);
  padding: 28px 22px 32px;
}

.sidebar__brand {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  text-decoration: none;
  letter-spacing: 0.02em;
  margin-bottom: 4px;
}

.sidebar__brand-sub {
  display: block;
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 28px;
}

.sidebar__group-label {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  margin: 22px 0 8px;
  padding-left: 4px;
}

.sidebar__nav {
  list-style: none;
  margin: 0;
  padding: 0;
}

.sidebar__nav li { margin: 0; }

.sidebar__nav a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 7px 10px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  color: var(--text-muted);
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: color 0.12s, background 0.12s, border-color 0.12s;
}

.sidebar__nav a:hover {
  color: var(--text);
  background: rgba(255,255,255,0.025);
}

.sidebar__nav a.active {
  color: var(--text);
  background: var(--accent-soft);
  border-left-color: var(--accent);
}

.sidebar__nav .num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-dim);
  min-width: 22px;
}

.sidebar__nav a.active .num { color: var(--accent); }

.sidebar__footer {
  margin-top: 32px;
  padding-top: 18px;
  border-top: 1px solid var(--border-soft);
  font-size: 12px;
  color: var(--text-dim);
  line-height: 1.5;
}

/* ===========================================================
   Content
   =========================================================== */

.content {
  padding: 48px 56px 96px;
  max-width: calc(var(--content-max) + 112px);
  width: 100%;
}

.content__inner { max-width: var(--content-max); }

.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--accent);
  margin-bottom: 8px;
}

h1, h2, h3, h4 {
  color: var(--text);
  line-height: 1.25;
  letter-spacing: -0.01em;
  font-weight: 600;
}

h1 {
  font-size: 30px;
  margin: 0 0 14px;
}

h2 {
  font-size: 21px;
  margin: 40px 0 12px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--border-soft);
}

h3 {
  font-size: 17px;
  margin: 28px 0 8px;
}

h4 {
  font-size: 14px;
  margin: 20px 0 6px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

p {
  margin: 0 0 16px;
  color: var(--text);
}

p.lead {
  font-size: 17px;
  color: var(--text-muted);
  margin-bottom: 28px;
}

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.12s;
}

a:hover { border-bottom-color: var(--accent); }

ul, ol {
  margin: 0 0 16px;
  padding-left: 22px;
}

li { margin: 4px 0; }

code {
  font-family: var(--font-mono);
  font-size: 13.5px;
  background: var(--kbd-bg);
  padding: 1px 6px;
  border-radius: var(--radius-sm);
  color: var(--text);
}

pre {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.55;
  color: var(--text);
  margin: 0 0 16px;
}

pre code {
  background: transparent;
  padding: 0;
  font-size: inherit;
  border-radius: 0;
}

hr {
  border: none;
  border-top: 1px solid var(--border-soft);
  margin: 36px 0;
}

blockquote {
  margin: 0 0 16px;
  padding: 10px 16px;
  border-left: 3px solid var(--text-dim);
  background: rgba(255,255,255,0.02);
  color: var(--text-muted);
  font-style: italic;
}

/* ===========================================================
   Callouts
   =========================================================== */

.callout {
  display: block;
  padding: 14px 16px;
  border-radius: var(--radius);
  margin: 0 0 20px;
  border: 1px solid;
  font-size: 14px;
  line-height: 1.6;
}

.callout p:last-child { margin-bottom: 0; }

.callout__title {
  display: block;
  font-weight: 600;
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 6px;
}

.callout--info {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--text);
}
.callout--info  .callout__title { color: var(--accent); }

.callout--warn {
  background: var(--warn-soft);
  border-color: var(--warn);
}
.callout--warn  .callout__title { color: var(--warn); }

.callout--danger {
  background: var(--danger-soft);
  border-color: var(--danger);
}
.callout--danger .callout__title { color: var(--danger); }

.callout--ok {
  background: var(--ok-soft);
  border-color: var(--ok);
}
.callout--ok .callout__title { color: var(--ok); }

/* ===========================================================
   OS tabs (for code blocks that vary by platform)
   =========================================================== */

.tabs {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 0 0 20px;
  overflow: hidden;
  background: var(--bg-code);
}

.tabs__bar {
  display: flex;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--border);
}

.tabs__btn {
  flex: 0 0 auto;
  background: transparent;
  border: none;
  border-right: 1px solid var(--border);
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 13px;
  padding: 9px 16px;
  cursor: pointer;
  transition: color 0.12s, background 0.12s;
}

.tabs__btn:hover { color: var(--text); }

.tabs__btn.active {
  color: var(--text);
  background: var(--bg-code);
  box-shadow: inset 0 -2px 0 0 var(--accent);
}

.tabs__panel { display: none; padding: 0; }
.tabs__panel.active { display: block; }

.tabs__panel pre {
  border: none;
  border-radius: 0;
  margin: 0;
  background: transparent;
}

.tabs__panel > p,
.tabs__panel > ul {
  padding: 0 16px 14px;
  margin: 0;
  font-size: 13.5px;
  color: var(--text-muted);
}

/* ===========================================================
   Page footer / nav
   =========================================================== */

.pager {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 56px;
  padding-top: 24px;
  border-top: 1px solid var(--border-soft);
}

.pager a {
  flex: 1 1 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  text-decoration: none;
  background: var(--bg-elev);
  transition: border-color 0.12s, background 0.12s;
}

.pager a:hover {
  border-color: var(--accent);
  background: var(--bg-elev);
}

.pager a.next { text-align: right; }

.pager small {
  display: block;
  font-size: 11px;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.pager strong {
  display: block;
  font-weight: 500;
  color: var(--text);
}

/* ===========================================================
   Learning outcomes list
   =========================================================== */

.lo-list {
  list-style: none;
  padding: 0;
  margin: 18px 0 24px;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  overflow: hidden;
}

.lo-list li {
  margin: 0;
  padding: 10px 16px;
  border-bottom: 1px solid var(--border-soft);
  display: flex;
  gap: 10px;
  align-items: baseline;
  font-size: 14px;
  color: var(--text-muted);
}

.lo-list li:last-child { border-bottom: none; }

.lo-list .lo-num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent);
  min-width: 32px;
}

/* ===========================================================
   Tables
   =========================================================== */

table {
  width: 100%;
  border-collapse: collapse;
  margin: 0 0 22px;
  font-size: 14px;
}

th, td {
  text-align: left;
  padding: 8px 12px;
  border-bottom: 1px solid var(--border-soft);
  vertical-align: top;
}

th {
  color: var(--text-dim);
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  background: var(--bg-elev);
}

td code { font-size: 12.5px; }

/* ===========================================================
   Severity pills (for findings tables)
   =========================================================== */

.sev {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 2px 8px;
  border-radius: 999px;
  border: 1px solid;
  line-height: 1.4;
}

.sev--crit  { color: var(--danger); border-color: var(--danger); background: var(--danger-soft); }
.sev--high  { color: var(--warn);   border-color: var(--warn);   background: var(--warn-soft); }
.sev--med   { color: var(--accent); border-color: var(--accent); background: var(--accent-soft); }
.sev--low   { color: var(--text-muted); border-color: var(--border); }
.sev--ok    { color: var(--ok);     border-color: var(--ok);     background: var(--ok-soft); }
.sev--info  { color: var(--text-dim); border-color: var(--border-soft); }

/* ===========================================================
   ASCII / schematic blocks
   =========================================================== */

.schematic {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.45;
  color: var(--text-muted);
  margin: 0 0 20px;
  overflow-x: auto;
  white-space: pre;
}

/* ===========================================================
   Chapter cards (homepage)
   =========================================================== */

.chapters {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin: 20px 0 24px;
}

.chapter {
  display: block;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-elev);
  color: var(--text);
  text-decoration: none;
  transition: border-color 0.12s, transform 0.12s;
}

.chapter:hover {
  border-color: var(--accent);
  border-bottom-color: var(--accent);
  transform: translateY(-1px);
}

.chapter__num {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-dim);
  letter-spacing: 0.06em;
  display: block;
  margin-bottom: 4px;
}

.chapter__title {
  font-weight: 600;
  font-size: 15px;
  margin: 0 0 4px;
}

.chapter__desc {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.5;
  margin: 0;
}

@media (max-width: 700px) {
  .chapters { grid-template-columns: 1fr; }
}

/* ===========================================================
   Glossary
   =========================================================== */

.gloss-letters {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0 0 24px;
  padding: 12px 14px;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  background: var(--bg-elev);
  font-family: var(--font-mono);
  font-size: 12px;
}

.gloss-letters a {
  color: var(--text-muted);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  text-decoration: none;
}

.gloss-letters a:hover {
  background: var(--accent-soft);
  color: var(--accent);
  border-bottom: none;
}

.gloss-letter {
  margin: 26px 0 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent);
  letter-spacing: 0.06em;
  padding-bottom: 4px;
  border-bottom: 1px solid var(--border-soft);
}

.gloss-letter:first-of-type { margin-top: 8px; }

dl.gloss {
  margin: 0 0 8px;
  padding: 0;
}

dl.gloss dt {
  font-weight: 600;
  color: var(--text);
  margin: 14px 0 4px;
  font-size: 15px;
}

dl.gloss dt small {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-dim);
  font-weight: 400;
  margin-left: 6px;
  letter-spacing: 0.04em;
}

dl.gloss dd {
  margin: 0;
  padding: 0;
  color: var(--text-muted);
  font-size: 14px;
  line-height: 1.6;
}

/* ===========================================================
   Hero (homepage only)
   =========================================================== */

.hero {
  margin-bottom: 32px;
}

.hero h1 {
  font-size: 34px;
  margin-bottom: 16px;
}

.hero__lead {
  font-size: 17px;
  color: var(--text-muted);
  margin-bottom: 24px;
  max-width: 640px;
}

.hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-dim);
  letter-spacing: 0.04em;
  padding: 10px 0;
  border-top: 1px solid var(--border-soft);
  border-bottom: 1px solid var(--border-soft);
  margin-bottom: 28px;
}

.hero__meta span strong {
  color: var(--text-muted);
  font-weight: 500;
  margin-right: 4px;
}

/* ===========================================================
   Footnotes & source citations
   -----------------------------------------------------------
   Inline superscript markers <sup class="fn-ref"> link down to
   a numbered list rendered as <ol class="footnotes">. Mapping
   tables get an extra "Sources" row styled like .tbl-sources.
   =========================================================== */

.fn-ref {
  font-size: 11px;
  vertical-align: super;
  line-height: 0;
  margin-left: 1px;
}

.fn-ref a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: none;
  padding: 0 2px;
  font-family: var(--font-mono);
  font-weight: 500;
}

.fn-ref a:hover { text-decoration: underline; }

.fn-back {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-dim);
  margin-left: 6px;
  text-decoration: none;
  border-bottom: none;
}
.fn-back:hover { color: var(--accent); border-bottom: none; }

.footnotes-section {
  margin-top: 56px;
  padding-top: 22px;
  border-top: 1px solid var(--border-soft);
}

.footnotes-section h2 {
  border-bottom: none;
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
  margin: 0 0 14px;
  padding-bottom: 0;
}

ol.footnotes {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: fn;
}

ol.footnotes li {
  position: relative;
  padding: 10px 0 10px 32px;
  border-bottom: 1px solid var(--border-soft);
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--text-muted);
  counter-increment: fn;
}

ol.footnotes li:last-child { border-bottom: none; }

ol.footnotes li::before {
  content: counter(fn);
  position: absolute;
  left: 0;
  top: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--accent);
  letter-spacing: 0.04em;
  width: 22px;
  text-align: right;
}

ol.footnotes a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  word-break: break-word;
}
ol.footnotes a:hover { border-bottom-color: var(--accent); }

ol.footnotes cite {
  font-style: italic;
  color: var(--text);
}

/* Sources row inside a mapping table */
.tbl-sources td {
  background: var(--bg);
  font-size: 12px;
  color: var(--text-dim);
  font-family: var(--font-mono);
  letter-spacing: 0.02em;
  padding-top: 10px;
  padding-bottom: 10px;
  border-top: 1px solid var(--border);
  border-bottom: none;
}

.tbl-sources a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  word-break: break-word;
}
.tbl-sources a:hover { border-bottom-color: var(--accent); }

.tbl-sources__label {
  display: inline-block;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  margin-right: 8px;
  font-weight: 600;
}

/* ===========================================================
   Self-check (per-section "Check yourself" quiz blocks)
   -----------------------------------------------------------
   Three multiple-choice questions per content page. Implemented
   with native <details>/<summary> — no JS framework. Each option
   is itself a <details> so the reader picks one and sees whether
   they were right, plus a one-sentence explanation.
   =========================================================== */

.selfcheck {
  margin: 48px 0 0;
  padding: 22px 22px 8px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-elev);
}

.selfcheck__heading {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 4px;
}

.selfcheck__title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text);
  margin: 0 0 6px;
}

.selfcheck__intro {
  font-size: 13.5px;
  color: var(--text-muted);
  margin: 0 0 18px;
  line-height: 1.55;
}

.selfcheck__q {
  border-top: 1px solid var(--border-soft);
  padding: 16px 0 14px;
}

.selfcheck__q:first-of-type { border-top: none; padding-top: 4px; }

.selfcheck__qnum {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-dim);
  letter-spacing: 0.06em;
  margin-bottom: 4px;
}

.selfcheck__qtext {
  font-size: 15px;
  font-weight: 500;
  color: var(--text);
  margin: 0 0 12px;
  line-height: 1.5;
}

/* Each option is a <details> the reader can expand to check
   their answer. The summary is the option text; the body is
   the verdict + one-sentence explanation. */

.selfcheck__opt {
  margin: 6px 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-code);
  overflow: hidden;
  transition: border-color 0.12s;
}

.selfcheck__opt:hover { border-color: var(--text-dim); }
.selfcheck__opt[open] { border-color: var(--accent); }

.selfcheck__opt > summary {
  list-style: none;
  cursor: pointer;
  padding: 9px 14px 9px 38px;
  position: relative;
  font-size: 13.5px;
  color: var(--text);
  line-height: 1.5;
  user-select: none;
}

.selfcheck__opt > summary::-webkit-details-marker { display: none; }

/* Letter bullet (A / B / C / D) sits in the gutter on the left. */
.selfcheck__opt > summary::before {
  content: attr(data-letter);
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-dim);
  width: 18px;
  height: 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: 3px;
  background: var(--bg-elev);
}

.selfcheck__opt[open] > summary::before {
  color: var(--accent);
  border-color: var(--accent);
}

.selfcheck__verdict {
  padding: 10px 14px 12px 38px;
  border-top: 1px solid var(--border-soft);
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-muted);
  background: var(--bg);
}

.selfcheck__verdict strong {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 1px 8px;
  border-radius: 3px;
  margin-right: 8px;
  vertical-align: 1px;
}

.selfcheck__verdict--ok strong {
  color: var(--ok);
  background: var(--ok-soft);
  border: 1px solid var(--ok);
}

.selfcheck__verdict--no strong {
  color: var(--danger);
  background: var(--danger-soft);
  border: 1px solid var(--danger);
}

/* ===========================================================
   Responsive
   =========================================================== */

@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar {
    position: static;
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--border);
    padding: 22px;
  }
  .content { padding: 32px 22px 64px; }
  .hero h1 { font-size: 26px; }
}