:root {
  --bg: #0E1220;
  --surface: #171C2F;
  --surface-2: #1F2539;
  --border: #2C3350;
  --ink: #E9EDF7;
  --muted: #8E97B4;
  --brand: #22C55E; /* verde Excel */
  --brand-dim: rgba(34,197,94,.15);
  --display: 'Space Grotesk', sans-serif;
  --body: 'Inter', sans-serif;
  --mono: 'JetBrains Mono', monospace;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { height: 100%; overflow: hidden; }
body { height: 100%; overflow-y: auto; background: var(--bg); color: var(--ink);
  font-family: var(--body); line-height: 1.6; -webkit-font-smoothing: antialiased; }

.wrap { max-width: 960px; margin: 0 auto; padding: 0 20px 120px; }
a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

/* topbar */
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 20px 0; border-bottom: 1px solid var(--border); }
.topbar .logo { display: flex; align-items: center; gap: 10px; }
.topbar .logo img { height: 26px; width: auto; display: block; }
.topbar .logo .fallback { font-family: var(--display); font-weight: 700; font-size: 1.05rem; letter-spacing: -.02em; }
.topbar .logo .fallback span { color: var(--brand); }
.topbar nav { font-family: var(--mono); font-size: .8rem; color: var(--muted);
  display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px 16px; }
.topbar nav a { white-space: nowrap; color: var(--muted); }
.topbar nav a:hover { color: var(--brand); text-decoration: none; }
.ico { width: 1em; height: 1em; stroke: currentColor; fill: none; stroke-width: 2;
  stroke-linecap: round; stroke-linejoin: round; vertical-align: -.1em; }
@media(max-width:420px) { .topbar .logo img { height: 22px; } .topbar nav { font-size: .74rem; } }

/* footer */
footer { margin-top: 60px; padding: 24px 0; border-top: 1px solid var(--border);
  text-align: center; font-size: .82rem; color: var(--muted); }
footer b { color: var(--brand); font-family: var(--display); font-weight: 700; }
.rodape-marca { display: inline-block; margin-bottom: 12px; opacity: .85; transition: opacity .16s; }
.rodape-marca:hover { opacity: 1; }
.rodape-marca img { height: 22px; width: auto; display: block; }

/* hero */
.hero { padding: 44px 0 32px; border-bottom: 1px solid var(--border); }
.aula-tag { font-family: var(--mono); font-size: .72rem; letter-spacing: .14em;
  text-transform: uppercase; color: var(--brand); margin-bottom: 12px; }
.hero h1 { font-family: var(--display); font-weight: 700;
  font-size: clamp(1.8rem, 5vw, 2.8rem); letter-spacing: -.02em; line-height: 1.1; }
.hero h1 em { font-style: normal; color: var(--brand); }
.lead { color: var(--muted); font-size: 1rem; margin-top: 12px; max-width: 60ch; }

/* barra de progresso */
.progresso { height: 3px; background: var(--border); margin: 0; }
.progresso-fill { height: 100%; background: var(--brand); transition: width .4s; }

/* teoria */
.teoria { background: var(--surface); border: 1px solid var(--border);
  border-radius: 12px; padding: 28px; margin-top: 32px; }
.teoria h2 { font-family: var(--display); font-size: 1.1rem; margin-bottom: 20px; color: var(--ink); }
.teoria h3 { font-family: var(--mono); font-size: .82rem; color: var(--brand);
  text-transform: uppercase; letter-spacing: .1em; margin: 20px 0 8px; }
.teoria p { color: var(--muted); font-size: .9rem; margin-bottom: 10px; }
.teoria ul { color: var(--muted); font-size: .9rem; padding-left: 20px; }
.teoria li { margin-bottom: 4px; }
.teoria pre { background: var(--surface-2); border: 1px solid var(--border);
  border-radius: 8px; padding: 14px 16px; font-family: var(--mono); font-size: .82rem;
  color: #A5D8FF; overflow-x: auto; margin: 8px 0; }
.teoria code { font-family: var(--mono); font-size: .85em;
  background: var(--surface-2); padding: 1px 5px; border-radius: 4px; color: #A5D8FF; }

/* exercícios */
.ex-section { margin-top: 32px; }
.ex-section-title { font-family: var(--mono); font-size: .72rem; letter-spacing: .14em;
  text-transform: uppercase; color: var(--muted); margin-bottom: 16px; }

.ex-block { background: var(--surface); border: 1px solid var(--border);
  border-radius: 12px; margin-bottom: 20px; overflow: hidden; }
.ex-head { display: flex; align-items: center; gap: 10px;
  padding: 14px 20px; border-bottom: 1px solid var(--border); flex-wrap: wrap; }
.ex-num { font-family: var(--mono); font-size: .72rem; color: var(--muted); }
.ex-title { font-family: var(--display); font-weight: 600; font-size: .95rem; flex: 1; }
.badge { font-family: var(--mono); font-size: .62rem; padding: 2px 8px;
  border-radius: 999px; font-weight: 600; text-transform: uppercase; }
.badge-ex { background: rgba(34,197,94,.15); color: var(--brand); border: 1px solid rgba(34,197,94,.3); }
.badge-desafio { background: rgba(251,191,36,.12); color: #FBbf24; border: 1px solid rgba(251,191,36,.3); }

.ex-body { padding: 20px; }
.ex-desc { color: var(--muted); font-size: .9rem; margin-bottom: 14px; line-height: 1.6; }

.dica { margin-bottom: 16px; }
.dica summary { font-family: var(--mono); font-size: .78rem; color: var(--brand);
  cursor: pointer; user-select: none; }
.dica p { color: var(--muted); font-size: .85rem; margin-top: 8px;
  padding: 10px 14px; background: var(--brand-dim); border-radius: 8px; }
.dica code { font-family: var(--mono); color: var(--brand); font-size: .85em; }

/* planilha container */
.sheet-wrap { position: relative; }
.sheet-container { width: 100%; height: 320px; border: 1px solid #ccc;
  border-radius: 8px; overflow: hidden; margin-bottom: 10px; background: #fff;
  font-family: Arial, sans-serif; }
.sheet-container.tall { height: 420px; }
.sheet-container > div { height: 100%; }

/* células a preencher — instrução visual */
.sheet-hint { font-family: var(--mono); font-size: .72rem; color: var(--muted);
  margin-bottom: 8px; display: flex; align-items: center; gap: 6px; }
.sheet-hint::before { content: ''; display: inline-block; width: 14px; height: 14px;
  background: rgba(34,197,94,.25); border: 1px solid rgba(34,197,94,.6); border-radius: 2px; }

.ex-footer { display: flex; align-items: center; gap: 12px;
  padding: 14px 20px; border-top: 1px solid var(--border); flex-wrap: wrap; }
.btn-check { font-family: var(--mono); font-size: .82rem; font-weight: 700;
  padding: 8px 20px; border-radius: 8px; border: none; cursor: pointer;
  background: var(--brand); color: #0a1a0f; transition: opacity .2s; }
.btn-check:hover { opacity: .85; }
.btn-check:disabled { opacity: .4; cursor: not-allowed; }

.resultado { font-family: var(--mono); font-size: .82rem; padding: 6px 12px;
  border-radius: 8px; display: none; }
.resultado.ok { background: rgba(34,197,94,.15); color: #22c55e;
  border: 1px solid rgba(34,197,94,.3); display: block; }
.resultado.err { background: rgba(239,68,68,.12); color: #f87171;
  border: 1px solid rgba(239,68,68,.3); display: block; }

/* navegação entre aulas */
.aula-nav { display: flex; align-items: center; justify-content: space-between;
  margin-top: 48px; padding-top: 24px; border-top: 1px solid var(--border); }
.nav-btn { font-family: var(--mono); font-size: .8rem; padding: 8px 18px;
  border-radius: 8px; border: 1px solid var(--border); color: var(--muted);
  background: var(--surface); transition: border-color .2s, color .2s; }
.nav-btn:hover { border-color: var(--brand); color: var(--brand); text-decoration: none; }
.nav-btn.next { background: var(--brand); color: #0a1a0f; border-color: var(--brand); font-weight: 700; }
.nav-btn.next:hover { opacity: .85; color: #0a1a0f; }
.nav-info { font-family: var(--mono); font-size: .75rem; color: var(--muted); }