/* Lesson look for "VPC in plain English". Scoped so the course header keeps the shared chrome. */
:root {
  --vpc-bg: #F2F6F6;
  --vpc-surface: #FFFFFF;
  --vpc-fg: #0F2B2E;
  --fg: #0F2B2E;
  --vpc-muted: #4B6568;
  --vpc-line: #C3D6D7;
  --vpc: #0B6B74;
  --vpc-tint: #DDF1F2;
  --pub: #17653F;
  --pub-tint: #DFF3E8;
  --priv: #3B4A8C;
  --priv-tint: #E4E8F6;
  --hot: #B34700;
  --hot-tint: #FCE9DA;
  --display: "Fredoka", "Trebuchet MS", system-ui, sans-serif;
  --body: "Nunito", system-ui, -apple-system, "Segoe UI", sans-serif;
  --vpc-mono: "JetBrains Mono", ui-monospace, Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --vpc-bg: #0C1A1C;
    --vpc-surface: #12272A;
    --vpc-fg: #E6F1F1;
    --fg: #E6F1F1;
    --vpc-muted: #9DB8BA;
    --vpc-line: #2B4A4D;
    --vpc: #5CCBD4;
    --vpc-tint: #123539;
    --pub: #62D494;
    --pub-tint: #12301F;
    --priv: #A3B1F5;
    --priv-tint: #1C2347;
    --hot: #FF9A55;
    --hot-tint: #3A2312;
  }
}

:root[data-theme="dark"] {
  --vpc-bg: #0C1A1C;
  --vpc-surface: #12272A;
  --vpc-fg: #E6F1F1;
  --fg: #E6F1F1;
  --vpc-muted: #9DB8BA;
  --vpc-line: #2B4A4D;
  --vpc: #5CCBD4;
  --vpc-tint: #123539;
  --pub: #62D494;
  --pub-tint: #12301F;
  --priv: #A3B1F5;
  --priv-tint: #1C2347;
  --hot: #FF9A55;
  --hot-tint: #3A2312;
}

main.vpc-page {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 44px;
  padding-inline: max(16px, env(safe-area-inset-left, 0px)) max(16px, env(safe-area-inset-right, 0px));
  padding-block: 28px 56px;
  background: var(--vpc-bg);
  color: var(--vpc-fg);
  font-family: var(--body);
  font-size: 17px;
  line-height: 1.6;
}

main.vpc-page h1,
main.vpc-page h2 {
  font-family: var(--display);
  line-height: 1.15;
  text-wrap: balance;
  margin: 0;
  border: 0;
  padding: 0;
}

main.vpc-page h1 {
  font-size: clamp(2.2rem, 7vw, 3.4rem);
  font-weight: 700;
  letter-spacing: -0.01em;
}

main.vpc-page h2 {
  font-size: clamp(1.45rem, 4vw, 1.85rem);
  font-weight: 600;
}

main.vpc-page p {
  margin: 0;
  max-width: 65ch;
}

main.vpc-page .sec {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

main.vpc-page .kicker {
  font-family: var(--vpc-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--vpc);
  font-weight: 700;
}

main.vpc-page .lede {
  font-size: 1.2rem;
  color: var(--vpc-muted);
}

main.vpc-page figure {
  margin: 0;
  background: var(--vpc-surface);
  border: 1.5px solid var(--vpc-line);
  border-radius: 16px;
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-width: 0;
}

main.vpc-page .scroll {
  overflow-x: auto;
}

main.vpc-page .scroll svg {
  display: block;
  width: 100%;
  min-width: 520px;
  height: auto;
}

main.vpc-page figcaption {
  font-size: 0.95rem;
  color: var(--vpc-muted);
}

main.vpc-page figcaption b {
  color: var(--vpc-fg);
}

main.vpc-page svg text {
  fill: var(--vpc-fg);
  font-family: var(--body);
  font-size: 14px;
}

main.vpc-page svg .b { font-weight: 800; }
main.vpc-page svg .m { fill: var(--vpc-muted); }
main.vpc-page svg .s { font-size: 12px; }
main.vpc-page svg .mono { font-family: var(--vpc-mono); font-size: 12px; }
main.vpc-page svg .c { text-anchor: middle; }
main.vpc-page svg .e { text-anchor: end; }
main.vpc-page svg .tv { fill: var(--vpc); }
main.vpc-page svg .tp { fill: var(--pub); }
main.vpc-page svg .tr { fill: var(--priv); }
main.vpc-page svg .th { fill: var(--hot); }
main.vpc-page svg .big { font-size: 16px; font-family: var(--display); font-weight: 600; }

main.vpc-page .city { fill: none; stroke: var(--vpc-line); stroke-width: 1.5; stroke-dasharray: 6 5; }
main.vpc-page .vpc { fill: var(--vpc-tint); stroke: var(--vpc); stroke-width: 2; }
main.vpc-page .pub { fill: var(--pub-tint); stroke: var(--pub); stroke-width: 2; }
main.vpc-page .priv { fill: var(--priv-tint); stroke: var(--priv); stroke-width: 2; }
main.vpc-page .gate { fill: var(--hot-tint); stroke: var(--hot); stroke-width: 2; }
main.vpc-page .net { fill: var(--vpc-surface); stroke: var(--vpc-muted); stroke-width: 1.5; }
main.vpc-page .srv { fill: var(--vpc-surface); stroke: var(--vpc-fg); stroke-width: 1.5; }
main.vpc-page .chip { fill: var(--vpc-surface); stroke: var(--vpc-line); stroke-width: 1.5; }
main.vpc-page .panel { fill: var(--vpc-surface); stroke: var(--vpc-line); stroke-width: 1.5; }
main.vpc-page .hl { fill: var(--hot-tint); }
main.vpc-page .dead { fill: none; stroke: var(--hot); stroke-width: 2; stroke-dasharray: 6 5; }
main.vpc-page .ln { stroke: var(--vpc-fg); stroke-width: 2; fill: none; }
main.vpc-page .road { stroke: var(--hot); stroke-width: 2.5; fill: none; }
main.vpc-page .noroad { stroke: var(--hot); stroke-width: 2.5; stroke-dasharray: 6 5; fill: none; }
main.vpc-page .x { stroke: var(--hot); stroke-width: 3; stroke-linecap: round; }

main.vpc-page .words {
  border: 1.5px solid var(--vpc-line);
  border-radius: 16px;
  background: var(--vpc-surface);
  overflow-x: auto;
}

main.vpc-page table {
  border-collapse: collapse;
  width: 100%;
  min-width: 560px;
  font-size: 0.98rem;
}

main.vpc-page th,
main.vpc-page td {
  text-align: left;
  padding: 11px 14px;
  vertical-align: top;
  border-bottom: 1px solid var(--vpc-line);
}

main.vpc-page th {
  font-family: var(--vpc-mono);
  font-size: 0.74rem;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--vpc-muted);
  font-weight: 700;
}

main.vpc-page tr:last-child td { border-bottom: 0; }
main.vpc-page td:first-child { font-weight: 800; white-space: nowrap; }

main.vpc-page code,
main.vpc-page .tag {
  font-family: var(--vpc-mono);
  font-size: 0.82rem;
}

main.vpc-page .tag {
  background: var(--vpc-tint);
  color: var(--vpc);
  border-radius: 6px;
  padding: 2px 7px;
  white-space: nowrap;
}

main.vpc-page .tag.none {
  background: transparent;
  color: var(--vpc-muted);
  border: 1px dashed var(--vpc-line);
}

main.vpc-page .pair {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 14px;
}

main.vpc-page .pair > div {
  background: var(--vpc-surface);
  border: 1.5px solid var(--vpc-line);
  border-radius: 14px;
  padding: 14px 16px;
  min-width: 0;
}

main.vpc-page .pair h3 {
  font-family: var(--display);
  font-weight: 600;
  font-size: 1.15rem;
  margin: 0 0 4px;
  border: 0;
  padding: 0;
}

main.vpc-page .pair p { font-size: 0.97rem; }

main.vpc-page .remember {
  display: flex;
  flex-direction: column;
  gap: 10px;
  counter-reset: r;
  padding: 0;
  margin: 0;
  list-style: none;
}

main.vpc-page .remember li {
  background: var(--vpc-surface);
  border: 1.5px solid var(--vpc-line);
  border-left: 6px solid var(--hot);
  border-radius: 12px;
  padding: 12px 16px;
  font-size: 1.05rem;
}

main.vpc-page .remember li b {
  font-family: var(--display);
  font-weight: 600;
}

main.vpc-page details {
  background: var(--vpc-surface);
  border: 1.5px solid var(--vpc-line);
  border-radius: 14px;
  padding: 12px 16px;
}

main.vpc-page summary {
  cursor: pointer;
  font-weight: 800;
}

main.vpc-page summary:focus-visible,
main.vpc-page a:focus-visible {
  outline: 3px solid var(--hot);
  outline-offset: 2px;
}

main.vpc-page .ids {
  font-family: var(--vpc-mono);
  font-size: 0.8rem;
  line-height: 1.9;
  margin-top: 8px;
  overflow-wrap: anywhere;
}

main.vpc-page .note {
  color: var(--vpc-muted);
  font-size: 0.95rem;
}

main.vpc-page .steps {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 18px;
  counter-reset: st;
}

main.vpc-page .steps > li {
  counter-increment: st;
  background: var(--vpc-surface);
  border: 1.5px solid var(--vpc-line);
  border-radius: 16px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-width: 0;
}

main.vpc-page .steps h3 {
  font-family: var(--display);
  font-weight: 600;
  font-size: 1.2rem;
  margin: 0;
  border: 0;
  padding: 0;
  display: flex;
  gap: 10px;
  align-items: center;
}

main.vpc-page .steps h3::before {
  content: counter(st);
  flex: none;
  width: 1.9rem;
  height: 1.9rem;
  border-radius: 50%;
  background: var(--hot-tint);
  color: var(--hot);
  border: 1.5px solid var(--hot);
  font-family: var(--vpc-mono);
  font-size: 0.85rem;
  font-weight: 700;
  display: grid;
  place-items: center;
}

main.vpc-page .steps p { font-size: 0.98rem; }

main.vpc-page .how {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
  gap: 14px;
}

main.vpc-page .how > div { min-width: 0; }

main.vpc-page .how h4 {
  font-family: var(--vpc-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--vpc-muted);
  margin: 0 0 6px;
}

main.vpc-page .how ol {
  margin: 0;
  padding-left: 1.2rem;
  font-size: 0.96rem;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

main.vpc-page pre {
  margin: 0;
  position: static;
  background: var(--vpc-bg);
  color: var(--vpc-fg);
  border: 1px solid var(--vpc-line);
  border-left: 1px solid var(--vpc-line);
  border-radius: 10px;
  padding: 10px 12px;
  overflow-x: auto;
  font-family: var(--vpc-mono);
  font-size: 0.76rem;
  line-height: 1.65;
}

main.vpc-page pre code {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
  background: transparent;
}

main.vpc-page .result {
  font-size: 0.93rem;
  background: var(--vpc-tint);
  border-radius: 10px;
  padding: 8px 12px;
}

main.vpc-page .result b { color: var(--vpc); }

main.vpc-page .pager {
  margin-top: 8px;
}

@media (max-width: 480px) {
  main.vpc-page { font-size: 16px; }
}

@media (prefers-reduced-motion: reduce) {
  main.vpc-page .scroll { scroll-behavior: auto; }
}