/* Identidade do Hub Extremo (DESIGN.md): uma cor forte, hairline em vez de sombra, Geist. */
:root {
  --emerald: #10b981; --emerald-text: #059669;
  --ink: #171717; --body: #333333; --mute: #525252; --faint: #737373;
  --canvas: #FCFCFC; --surface: #FFFFFF; --elevated: #FAFAFA; --hover: #F5F5F5;
  --line-soft: #F4F4F4; --line: #ECECEC; --line-strong: #D4D4D4;
  --code-bg: #171717; --code-ink: #FAFAFA;
  --sans: "Geist", -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  --mono: "Geist Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}
@media (prefers-color-scheme: dark) {
  :root {
    --emerald-text: #34d399;
    --ink: #FAFAFA; --body: #D5D5D5; --mute: #B2B2B2; --faint: #909090;
    --canvas: #0A0A0A; --surface: #171717; --elevated: #262626; --hover: #262626;
    --line-soft: #1f1f1f; --line: #262626; --line-strong: #3a3a3a;
    --code-bg: #0A0A0A; --code-ink: #FAFAFA;
  }
}
* { box-sizing: border-box; }
html { color-scheme: light dark; }
body {
  margin: 0; background: var(--canvas); color: var(--body);
  font-family: var(--sans); font-size: 15px; line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--emerald-text); text-decoration: none; }
a:hover { text-decoration: underline; }
.mono { font-family: var(--mono); font-size: .85em; }
::selection { background: rgba(16,185,129,.25); }
:focus-visible { outline: 2px solid var(--emerald); outline-offset: 2px; border-radius: 6px; }

/* Topo */
.top {
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 12px 24px; border-bottom: 1px solid var(--line); background: var(--surface);
  position: sticky; top: 0; z-index: 10;
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); font-weight: 600; letter-spacing: -0.01em; }
.brand:hover { text-decoration: none; }
.topnav a { color: var(--mute); padding: 8px 14px; border-radius: 9999px; font-size: 13px; font-weight: 500; }
.topnav a:hover { background: var(--hover); text-decoration: none; }
.topnav a.on { color: var(--emerald-text); }

/* Layout */
.shell { display: grid; grid-template-columns: 260px 1fr; min-height: calc(100vh - 49px); }
.side { border-right: 1px solid var(--line); padding: 20px 12px; position: sticky; top: 49px; height: calc(100vh - 49px); overflow: auto; }
.side nav { display: flex; flex-direction: column; gap: 2px; }
.side a { display: flex; gap: 10px; align-items: baseline; color: var(--mute); padding: 8px 12px; border-radius: 9999px; font-size: 13px; font-weight: 500; }
.side a .mono { color: var(--faint); min-width: 2ch; }
.side a:hover { background: var(--hover); text-decoration: none; color: var(--ink); }
.side a.on { color: var(--emerald-text); background: var(--elevated); }
.side a.on .mono { color: var(--emerald-text); }
.main { padding: 40px 48px 80px; max-width: 900px; width: 100%; }
.foot { border-top: 1px solid var(--line); padding: 16px 24px; color: var(--faint); font-size: 12px; }

@media (max-width: 860px) {
  .shell { grid-template-columns: 1fr; }
  .side { position: static; height: auto; border-right: 0; border-bottom: 1px solid var(--line); padding: 8px 12px; }
  .side nav { flex-direction: row; overflow-x: auto; }
  .side a { white-space: nowrap; }
  .main { padding: 24px 20px 60px; }
}

/* Tipografia */
h1 { font-size: 28px; font-weight: 600; line-height: 1.1; letter-spacing: -0.022em; color: var(--ink); margin: 6px 0 12px; }
h1 .num { color: var(--emerald-text); font-size: .7em; margin-right: 6px; }
h2 { font-size: 18px; font-weight: 600; line-height: 1.25; letter-spacing: -0.017em; color: var(--ink); margin: 36px 0 12px; }
h3 { font-size: 15px; font-weight: 600; color: var(--ink); margin: 20px 0 6px; }
p { margin: 0 0 12px; }
.kicker { font-size: 12px; font-weight: 500; color: var(--mute); display: flex; align-items: center; gap: 8px; margin: 0; }
.dot { width: 5px; height: 5px; border-radius: 50%; background: var(--emerald); display: inline-block; }
.lead { font-size: 17px; color: var(--body); max-width: 62ch; margin-bottom: 8px; }
.muted { color: var(--faint); font-size: 13px; }
.label { font-size: 12px; font-weight: 500; color: var(--mute); }
.empty { color: var(--faint); border: 1px dashed var(--line-strong); border-radius: 12px; padding: 24px; text-align: center; }

/* Cards */
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 12px; }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; margin-bottom: 12px; }
.card.link { display: flex; flex-direction: column; gap: 6px; color: var(--ink); transition: border-color .12s, background .12s; margin: 0; }
.card.link:hover { text-decoration: none; border-color: var(--emerald); background: var(--elevated); }
.card.link strong { font-size: 15px; font-weight: 600; }
.card > :first-child { margin-top: 0; }
.card > :last-child { margin-bottom: 0; }
.card h2:first-child { margin-top: 0; }
.card.doc { max-width: 72ch; }
.card blockquote { margin: 0 0 12px; padding: 0 0 0 14px; border-left: 2px solid var(--emerald); color: var(--mute); }
.card ul, .card ol { padding-left: 22px; }
.card li { margin-bottom: 4px; }
.card table { border-collapse: collapse; width: 100%; font-size: 14px; margin-bottom: 12px; }
.card th, .card td { text-align: left; padding: 8px 10px; border-bottom: 1px solid var(--line); vertical-align: top; }
.card th { font-size: 12px; font-weight: 500; color: var(--mute); }
.card hr { border: 0; border-top: 1px solid var(--line); margin: 20px 0; }
.card input[type=checkbox] { accent-color: var(--emerald); }

/* Código com copiar */
.code { position: relative; margin: 8px 0 16px; }
.code pre { margin: 0; background: var(--code-bg); color: var(--code-ink); border-radius: 8px; padding: 16px 18px; overflow-x: auto; font-family: var(--mono); font-size: 13px; line-height: 1.5; white-space: pre-wrap; }
.code .copy {
  position: absolute; top: 8px; right: 8px; font: 500 12px var(--sans);
  background: var(--surface); color: var(--ink); border: 1px solid var(--line-strong); border-radius: 9999px; padding: 4px 12px; cursor: pointer;
}
.code .copy:hover { border-color: var(--emerald); color: var(--emerald-text); }
code:not(pre code) { font-family: var(--mono); font-size: .9em; background: var(--elevated); border: 1px solid var(--line); border-radius: 4px; padding: 1px 5px; }

/* Método */
.metodo { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
.metodo li { background: var(--surface); padding: 14px 16px; display: flex; flex-direction: column; gap: 4px; }
.metodo .num { color: var(--emerald-text); font-weight: 500; }
.metodo strong { color: var(--ink); }

/* Tabela do bônus */
.tabela { border-collapse: collapse; width: 100%; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
.tabela th, .tabela td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--line); }
.tabela th { font-size: 12px; font-weight: 500; color: var(--mute); }
.tabela tr:last-child td { border-bottom: 0; }

/* Paginação */
.pager { display: flex; justify-content: space-between; gap: 16px; margin-top: 48px; padding-top: 16px; border-top: 1px solid var(--line); font-size: 14px; font-weight: 500; }

/* Bloco "nesta aula" */
.nesta { margin-top: 24px; }
.nesta .card h2 { margin: 0 0 8px; font-size: 15px; }
.nesta ol { margin: 0; padding-left: 22px; color: var(--body); }
.nesta li { margin-bottom: 6px; }
.grid3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 12px; }
.grid3 .card { margin: 0; }
.grid3 .label { display: block; margin-bottom: 4px; }
.grid3 p { margin: 0; color: var(--ink); font-size: 14px; }

/* Slides da aula */
.slides-head { display: flex; justify-content: space-between; align-items: flex-end; gap: 16px; margin-bottom: 12px; }
.slides-head h2 { margin: 36px 0 4px; }
.slides-head p { margin: 0; }
.btn { display: inline-flex; align-items: center; gap: 6px; background: var(--emerald); color: #062b1c; font-weight: 600; font-size: 13px; padding: 10px 20px; border-radius: 9999px; white-space: nowrap; }
.btn:hover { text-decoration: none; background: #059669; color: #fff; }
.slide-list { list-style: none; margin: 0; padding: 0; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
.slide-list li + li { border-top: 1px solid var(--line); }
.slide-list a { display: flex; gap: 14px; align-items: center; padding: 12px 16px; color: var(--ink); font-size: 14px; }
.slide-list a:hover { background: var(--hover); text-decoration: none; }
.slide-list .num { color: var(--emerald-text); }