:root {
  --color-bg: #f4f6f8;
  --color-primary: #1a5fb4;
  --color-primary-dark: #103c73;
  --color-danger: #c0392b;
  --color-success: #1e8449;
  --color-text: #1c2b36;
  --color-card: #ffffff;
  --color-border: #d7dee3;
  font-size: 16px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
}

.app-header {
  background: var(--color-primary);
  color: white;
  padding: 1rem;
  text-align: center;
}

.app-header h1 {
  margin: 0;
  font-size: 1.25rem;
}

#app {
  max-width: 640px;
  margin: 0 auto;
  padding: 1rem;
}

.screen {
  background: var(--color-card);
  border-radius: 12px;
  padding: 1.25rem;
  box-shadow: 0 1px 4px rgba(0,0,0,0.08);
}

.hidden {
  display: none;
}

.btn {
  -webkit-appearance: none;
  appearance: none;
  display: block;
  width: 100%;
  padding: 0.85rem;
  margin: 0.5rem 0;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font: inherit;
  cursor: pointer;
}

.btn-primary {
  background: var(--color-primary);
  color: white;
}

.btn-primary:hover {
  background: var(--color-primary-dark);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  color: inherit;
}

.btn:disabled:hover {
  background: var(--color-primary);
}

.btn-secondary {
  background: white;
  color: var(--color-primary);
  border: 1px solid var(--color-primary);
}

.btn:focus-visible,
.alternativa:focus-visible,
#form-tema select:focus-visible,
#form-tema input:focus-visible {
  outline: 3px solid #f5a000;
  outline-offset: 2px;
}

#form-tema {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

#form-tema select,
#form-tema input {
  width: 100%;
  padding: 0.6rem;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-size: 1rem;
  font-family: inherit;
  background: white;
  color: var(--color-text);
}

#form-tema select {
  -webkit-appearance: none;
  appearance: none;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'><path d='M1 1l5 5 5-5' stroke='%231c2b36' stroke-width='1.5' fill='none' stroke-linecap='round' stroke-linejoin='round'/></svg>");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  padding-right: 2rem;
}

.campo-info {
  font-size: 0.8rem;
  opacity: 0.7;
  margin-top: -0.2rem;
}

.exam-bar {
  display: flex;
  justify-content: space-between;
  font-weight: 600;
  margin-bottom: 1rem;
}

.alternativas {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin: 1rem 0;
}

.alternativa {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: white;
  color: var(--color-text);
  font: inherit;
  text-align: left;
  cursor: pointer;
}

.alternativa.selecionada {
  border-color: var(--color-primary);
  background: #e8f0fb;
  font-weight: 600;
}

.alternativa.respondida {
  cursor: default;
}

.alternativa.certa {
  border-color: var(--color-success);
  background: #e6f7ec;
  font-weight: 600;
}

.alternativa.errada {
  border-color: #d9364a;
  background: #fce8ea;
  font-weight: 600;
}

.exam-nav {
  display: flex;
  gap: 0.5rem;
}

.exam-nav .btn {
  flex: 1;
}

#result-status.aprovado {
  color: var(--color-success);
}

#result-status.reprovado {
  color: var(--color-danger);
}

.revisao-item {
  border-top: 1px solid var(--color-border);
  padding: 0.75rem 0;
}

.questao-meta {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  opacity: 0.6;
  margin-bottom: 0.25rem;
}

.codigo-placa {
  display: inline-block;
  margin: 0 0 0.75rem;
  padding: 0.35rem 0.55rem;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  background: var(--color-bg);
  font-size: 0.85rem;
  font-weight: 700;
}

.codigo-placa.hidden {
  display: none;
}

.fonte-info {
  font-size: 0.8rem;
  opacity: 0.7;
}

.revisao-item .certa {
  color: var(--color-success);
}

.revisao-item .errada {
  color: var(--color-danger);
}

.result-stats {
  margin: 1rem 0;
}

.stats-resumo {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.6rem;
  margin-bottom: 1.25rem;
}

.stat-tile {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 0.75rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 0.15rem;
}

.stat-valor {
  font-size: 1.4rem;
  font-weight: 700;
}

.stat-valor.certa {
  color: var(--color-success);
}

.stat-valor.errada {
  color: var(--color-danger);
}

.stat-rotulo {
  font-size: 0.8rem;
  opacity: 0.75;
}

.stats-categorias h3 {
  margin: 0 0 0.6rem;
  font-size: 1rem;
}

.stat-categoria {
  margin-bottom: 0.7rem;
}

.stat-categoria-topo {
  display: flex;
  justify-content: space-between;
  font-size: 0.9rem;
  margin-bottom: 0.25rem;
}

.stat-barra {
  background: var(--color-border);
  border-radius: 999px;
  height: 8px;
  overflow: hidden;
}

.stat-barra-preenchida {
  background: var(--color-primary);
  height: 100%;
  border-radius: 999px;
}

.stats-destaque {
  font-size: 0.9rem;
  font-style: italic;
  margin-top: 0.5rem;
}

@media (min-width: 768px) {
  #app {
    max-width: 800px;
    padding: 2rem;
  }

  .exam-nav {
    max-width: 400px;
    margin-left: auto;
  }

  .stats-resumo {
    grid-template-columns: repeat(5, 1fr);
  }
}