:root {
  --fundo: #ffffff;
  --superficie: #fafafa;
  --texto: #0a0a0a;
  --suave: #6b7280;
  --borda: #e5e7eb;
  --acento: #111827;
  --realce: #2563eb;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--fundo);
  color: var(--texto);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

.oculto { display: none !important; }

.tela { height: 100%; display: flex; flex-direction: column; }

.cabecalho {
  padding: 28px 40px;
}

.marca {
  font-weight: 700;
  letter-spacing: -0.02em;
  text-decoration: none;
  color: var(--texto);
  font-size: 16px;
}

.centro {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 24px;
  max-width: 720px;
  margin: 0 auto;
}

.centro h1 {
  font-size: clamp(28px, 5vw, 44px);
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin: 0 0 16px;
}

.legenda {
  color: var(--suave);
  font-size: 17px;
  line-height: 1.6;
  margin: 0 0 32px;
  max-width: 540px;
}

.acoes {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}

.botao {
  appearance: none;
  border: 1px solid var(--borda);
  background: var(--fundo);
  color: var(--texto);
  font-size: 14px;
  font-weight: 600;
  padding: 11px 18px;
  border-radius: 8px;
  cursor: pointer;
  transition: transform 0.15s ease, background 0.15s ease, border-color 0.15s ease;
}

.botao:hover { transform: translateY(-1px); }

.botao.primario {
  background: var(--acento);
  color: #ffffff;
  border-color: var(--acento);
}

.botao.secundario:hover { border-color: var(--suave); }

.recentes {
  margin-top: 48px;
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.recente {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 18px;
  border: 1px solid var(--borda);
  border-radius: 10px;
  text-decoration: none;
  color: var(--texto);
  background: var(--superficie);
  transition: border-color 0.15s ease;
}

.recente:hover { border-color: var(--suave); }
.recente .nome { font-weight: 600; }
.recente .quando { color: var(--suave); font-size: 13px; }

.barra {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 14px 24px;
  border-bottom: 1px solid var(--borda);
}

.titulo {
  flex: 1;
  border: none;
  background: transparent;
  font-size: 16px;
  font-weight: 600;
  color: var(--texto);
  outline: none;
  min-width: 0;
}

.estado {
  color: var(--suave);
  font-size: 13px;
  white-space: nowrap;
}

.barra-acoes { display: flex; gap: 8px; }

.alternador {
  display: none;
  border-bottom: 1px solid var(--borda);
}

.aba {
  flex: 1;
  border: none;
  background: transparent;
  padding: 12px;
  font-size: 14px;
  font-weight: 600;
  color: var(--suave);
  cursor: pointer;
}

.aba.ativa { color: var(--texto); box-shadow: inset 0 -2px 0 var(--acento); }

.paineis {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-height: 0;
}

.fonte {
  border: none;
  border-right: 1px solid var(--borda);
  resize: none;
  padding: 32px;
  font-family: "SF Mono", "Cascadia Code", Consolas, monospace;
  font-size: 14px;
  line-height: 1.7;
  color: var(--texto);
  outline: none;
  background: var(--fundo);
}

.visualizacao {
  padding: 32px 40px;
  overflow-y: auto;
}

.markdown { line-height: 1.7; font-size: 16px; }
.markdown h1, .markdown h2, .markdown h3 { letter-spacing: -0.02em; line-height: 1.25; margin: 1.6em 0 0.6em; }
.markdown h1 { font-size: 2em; border-bottom: 1px solid var(--borda); padding-bottom: 0.3em; }
.markdown h2 { font-size: 1.5em; border-bottom: 1px solid var(--borda); padding-bottom: 0.3em; }
.markdown h3 { font-size: 1.2em; }
.markdown p { margin: 0 0 1em; }
.markdown a { color: var(--realce); }
.markdown code {
  background: var(--superficie);
  border: 1px solid var(--borda);
  padding: 2px 6px;
  border-radius: 6px;
  font-family: "SF Mono", "Cascadia Code", Consolas, monospace;
  font-size: 0.88em;
}
.markdown pre {
  background: #0d1117;
  color: #e6edf3;
  padding: 18px;
  border-radius: 10px;
  overflow-x: auto;
}
.markdown pre code { background: none; border: none; padding: 0; color: inherit; }
.markdown blockquote {
  margin: 0 0 1em;
  padding: 4px 18px;
  border-left: 3px solid var(--borda);
  color: var(--suave);
}
.markdown table { border-collapse: collapse; width: 100%; margin: 0 0 1em; }
.markdown th, .markdown td { border: 1px solid var(--borda); padding: 8px 12px; text-align: left; }
.markdown th { background: var(--superficie); }
.markdown img { max-width: 100%; border-radius: 8px; }
.markdown hr { border: none; border-top: 1px solid var(--borda); margin: 2em 0; }
.markdown ul, .markdown ol { padding-left: 1.4em; margin: 0 0 1em; }

@media (max-width: 760px) {
  .alternador { display: flex; }
  .paineis { grid-template-columns: 1fr; }
  .fonte { border-right: none; }
  .paineis[data-ativo="escrita"] .visualizacao { display: none; }
  .paineis[data-ativo="leitura"] .fonte { display: none; }
  .barra { flex-wrap: wrap; }
  .titulo { order: 3; flex-basis: 100%; }
}