/* Site do livro Fundamentos de CAN, J1939 e ISOBUS.
   Mesma paleta do livro; fontes do sistema, sem recursos externos. */

:root {
  --charcoal: #1F2937;
  --ink: #0F172A;
  --slate: #475569;
  --gray: #64748B;
  --lgray: #E2E8F0;
  --bg: #F8FAFC;
  --white: #FFFFFF;
  --bluegray: #52677D;
  --border: #CBD5E1;
  --text: #334155;
  --rule: #94A3B8;
  --soft: #F1F5F9;
  --green: #3F6B5A;
  --greenbg: #F1F6F3;
  --sans: "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
  --mono: Consolas, "SF Mono", Menlo, "Liberation Mono", monospace;
  --largura: 1080px;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--white);
  color: var(--text);
  font: 17px/1.6 var(--sans);
  -webkit-text-size-adjust: 100%;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--charcoal); }
a:focus-visible, button:focus-visible, summary:focus-visible { outline: 3px solid var(--rule); outline-offset: 3px; }
h1, h2, h3 { color: var(--charcoal); line-height: 1.2; letter-spacing: -.01em; }
h2 { font-size: 1.9rem; font-weight: 600; margin: 0 0 .4em; }
h3 { font-size: 1.1rem; font-weight: 600; margin: 0 0 .5em; }
p { margin: 0 0 1em; }
.caixa { max-width: var(--largura); margin: 0 auto; padding: 0 24px; }
.secao { padding: 72px 0; }
.secao.clara { background: var(--bg); border-top: 1px solid var(--lgray); border-bottom: 1px solid var(--lgray); }
.chamada-secao { color: var(--gray); font-size: 1.05rem; max-width: 46em; margin-bottom: 2em; }
.rotulo {
  color: var(--gray); font-size: .78rem; letter-spacing: .2em; text-transform: uppercase; margin: 0 0 .8em;
}

/* Topo */
.topo { background: var(--charcoal); color: var(--white); }
.topo nav { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 18px 24px; }
.topo .marca { color: var(--white); text-decoration: none; font-weight: 600; letter-spacing: .01em;
  display: flex; align-items: center; gap: 10px; font-size: 1.05rem; }
.topo ul { display: flex; flex-wrap: wrap; gap: 4px 20px; list-style: none; margin: 0; padding: 0; font-size: .92rem; }
.topo ul a { color: var(--border); text-decoration: none; }
.topo ul a:hover { color: var(--white); }

/* Destaque */
.destaque { background: var(--charcoal); color: var(--white); position: relative; overflow: hidden; }
.destaque .caixa { display: grid; grid-template-columns: 1.25fr .75fr; gap: 56px; align-items: center; padding-top: 48px; padding-bottom: 150px; position: relative; z-index: 1; }
.destaque .rotulo { color: var(--rule); }
.destaque h1 { color: var(--white); font-size: 3.1rem; font-weight: 600; letter-spacing: -.03em; margin: 0 0 .25em; }
.destaque h1 span { display: block; font-size: 1.35rem; font-weight: 300; color: var(--border); letter-spacing: 0; margin-bottom: .35em; }
.destaque .subtitulo { font-size: 1.3rem; font-weight: 300; color: var(--border); margin-bottom: 1.2em; }
.destaque .lema { color: var(--white); font-size: 1.2rem; font-weight: 600; line-height: 1.45; max-width: 30em; margin-bottom: .7em; }
.destaque .lead { color: var(--lgray); max-width: 34em; }
.destaque .ficha { color: var(--rule); font-size: .92rem; margin-top: 1.4em; }
.destaque .capa { box-shadow: 0 18px 50px rgba(0, 0, 0, .45); border: 1px solid var(--bluegray); max-width: 340px; justify-self: end; }
.barramento { position: absolute; left: 0; right: 0; bottom: 18px; width: 100%; height: 120px; }

.botoes { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 1.6em; }
.botao {
  display: inline-block; padding: 12px 22px; border-radius: 6px; font-weight: 600; font-size: .98rem;
  text-decoration: none; border: 1px solid transparent; line-height: 1.3;
}
.botao.primario { background: var(--white); color: var(--charcoal); }
.botao.primario:hover { background: var(--lgray); }
.botao.contorno { border-color: var(--rule); color: var(--white); }
.botao.contorno:hover { border-color: var(--white); }
.botao.escuro { background: var(--charcoal); color: var(--white); }
.botao.escuro:hover { background: var(--ink); }
.botao.breve { border-color: var(--bluegray); color: var(--rule); cursor: default; }
.botao small { display: block; font-weight: 400; font-size: .78rem; }

/* Numeros */
.numeros { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(6, 1fr); gap: 16px; }
.numeros li { border-left: 2px solid var(--border); padding: 4px 0 4px 14px; color: var(--gray); font-size: .9rem; line-height: 1.35; }
.numeros strong { display: block; color: var(--charcoal); font-size: 1.9rem; font-weight: 600; line-height: 1.1; }

/* Listas e grades */
.objetivos { columns: 2; column-gap: 48px; padding-left: 1.1em; margin: 0; }
.objetivos li { break-inside: avoid; margin-bottom: .7em; }
.grade-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.cartao { background: var(--white); border: 1px solid var(--border); border-radius: 8px; padding: 24px 26px; }
.cartao .rotulo { margin-bottom: .4em; }
.cartao ol { margin: 0; padding-left: 1.4em; }
.cartao li { margin-bottom: .25em; }
.apendices { margin-top: 24px; color: var(--gray); }

/* Por dentro */
.paginas { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
.paginas figure { margin: 0; }
.paginas a { display: block; border: 1px solid var(--border); box-shadow: 0 8px 24px rgba(15, 23, 42, .10); transition: transform .15s ease; }
.paginas a:hover { transform: translateY(-3px); }
.paginas figcaption { color: var(--gray); font-size: .92rem; margin-top: 12px; }

/* Casos */
.casos { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.casos li { background: var(--greenbg); border-top: 3px solid var(--green); padding: 16px 18px; border-radius: 0 0 6px 6px; color: var(--charcoal); font-weight: 600; line-height: 1.35; }
.casos li span { display: block; color: var(--green); font-size: .78rem; letter-spacing: .15em; text-transform: uppercase; font-weight: 600; margin-bottom: 6px; }

/* Amostra */
.amostra { display: grid; grid-template-columns: 1fr auto; gap: 32px; align-items: center; background: var(--charcoal); color: var(--lgray); border-radius: 10px; padding: 36px 40px; }
.amostra h2 { color: var(--white); }
.amostra p { margin: 0; }

/* Autor */
.autor { display: grid; grid-template-columns: 120px 1fr; gap: 32px; align-items: start; }
.avatar {
  width: 120px; height: 120px; border-radius: 50%; background: var(--charcoal); color: var(--white);
  display: grid; place-items: center; font-size: 2.2rem; font-weight: 600; letter-spacing: .02em;
}

/* Perguntas */
.perguntas details { border-bottom: 1px solid var(--lgray); padding: 16px 0; }
.perguntas summary { cursor: pointer; font-weight: 600; color: var(--charcoal); list-style: none; display: flex; justify-content: space-between; gap: 16px; }
.perguntas summary::-webkit-details-marker { display: none; }
.perguntas summary::after { content: "+"; color: var(--gray); font-weight: 400; font-size: 1.3rem; line-height: 1; }
.perguntas details[open] summary::after { content: "–"; }
.perguntas details p { margin: .8em 0 0; max-width: 52em; }

/* Rodape */
.rodape { background: var(--ink); color: var(--rule); font-size: .9rem; padding: 40px 0; }
.rodape p { margin: 0 0 .5em; }
.rodape strong { color: var(--lgray); font-weight: 600; }

code { font-family: var(--mono); font-size: .92em; }

@media (max-width: 900px) {
  .destaque .caixa { grid-template-columns: 1fr; gap: 36px; padding-bottom: 130px; }
  .destaque .capa { justify-self: start; max-width: 260px; }
  .numeros { grid-template-columns: repeat(3, 1fr); }
  .paginas { grid-template-columns: 1fr 1fr; }
  .casos { grid-template-columns: 1fr 1fr; }
  .amostra { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  body { font-size: 16px; }
  .secao { padding: 52px 0; }
  .topo nav { flex-direction: column; align-items: flex-start; }
  .destaque h1 { font-size: 2.3rem; }
  .destaque .subtitulo { font-size: 1.12rem; }
  .numeros { grid-template-columns: 1fr 1fr; }
  .objetivos { columns: 1; }
  .grade-2, .paginas, .casos { grid-template-columns: 1fr; }
  .amostra { padding: 28px 24px; }
  .autor { grid-template-columns: 1fr; }
  h2 { font-size: 1.55rem; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .paginas a { transition: none; }
}

/* ---------- Folheador da amostra (adaptado do leitor do Fólio) ---------- */
.leitor {
  position: relative; border-radius: 12px; padding: 14px 16px 10px; color: var(--border);
  background: radial-gradient(ellipse at 50% 38%, #334155, var(--ink));
  box-shadow: 0 22px 50px rgba(15, 23, 42, .22); outline: none;
}
.leitor:focus-visible { outline: 3px solid var(--rule); outline-offset: 4px; }
.palco { position: relative; height: clamp(440px, 74vh, 800px); overflow: hidden; }
.moldura { position: absolute; inset: 26px 64px 34px; animation: entrada .7s ease both; }
.moldura #livro, .moldura .stf__wrapper, .moldura .stf__block { width: 100%; height: 100%; }
.moldura .stf__block { transition: transform .45s ease; }
.moldura.capa:not(.retrato) .stf__block { transform: translateX(var(--desloc-capa, -25%)); }
.moldura.contracapa:not(.retrato) .stf__block { transform: translateX(var(--desloc-fim, 25%)); }
.moldura .page { background: var(--white); overflow: hidden; position: relative; box-shadow: 0 14px 30px rgba(0, 0, 0, .35); }
.moldura .page img { width: 100%; height: 100%; object-fit: contain; display: block; user-select: none; pointer-events: none; }
.moldura .page::after { content: ""; position: absolute; inset: 0; pointer-events: none; box-shadow: inset 0 0 2px rgba(0, 0, 0, .13); }
.moldura .page.--left::after { background: linear-gradient(to left, rgba(0, 0, 0, .07), transparent 9%); }
.moldura .page.--right::after { background: linear-gradient(to right, rgba(0, 0, 0, .06), transparent 9%); }
.seta {
  position: absolute; top: 50%; z-index: 3; width: 40px; height: 56px; margin-top: -28px;
  border: 0; border-radius: 6px; background: transparent; color: var(--rule); cursor: pointer; padding: 0;
  display: grid; place-items: center;
}
.seta:hover:not(:disabled) { background: rgba(255, 255, 255, .08); color: var(--white); }
.seta:disabled { opacity: .25; cursor: default; }
.seta svg { width: 28px; height: 28px; }
.seta.anterior { left: 8px; }
.seta.proxima { right: 8px; }
.dica { position: absolute; bottom: 8px; left: 0; right: 0; text-align: center; font-size: .78rem; color: var(--rule); pointer-events: none; }
.leitor svg { fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.barra {
  display: flex; align-items: center; justify-content: space-between; gap: 10px;
  border-top: 1px solid rgba(148, 163, 184, .18); padding-top: 10px; margin-top: 4px;
}
.barra .grupo, .paginacao { display: flex; align-items: center; gap: 4px; }
.icone {
  width: 36px; height: 36px; padding: 7px; border: 0; border-radius: 6px; background: transparent;
  color: var(--border); display: inline-grid; place-items: center; cursor: pointer; font: inherit;
}
.icone:hover:not(:disabled) { background: rgba(255, 255, 255, .08); color: var(--white); }
.icone:disabled { opacity: .3; cursor: default; }
.icone svg { width: 20px; height: 20px; }
.paginacao label { display: flex; align-items: center; gap: 4px; margin: 0 8px; font-size: .9rem; color: var(--rule); white-space: nowrap; }
.paginacao input {
  width: 2.8em; padding: 4px 0; border: 1px solid rgba(148, 163, 184, .35); border-radius: 4px;
  background: transparent; color: var(--white); font: inherit; text-align: center; -moz-appearance: textfield; appearance: textfield;
}
.paginacao input::-webkit-inner-spin-button, .paginacao input::-webkit-outer-spin-button { -webkit-appearance: none; margin: 0; }
.rotulo-pagina { min-width: 10em; font-size: .85rem; color: var(--rule); }
.leitor-rodape { display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; margin-top: 20px; color: var(--gray); font-size: .95rem; }
.leitor-rodape p { margin: 0; }
.leitor:fullscreen { border-radius: 0; display: flex; flex-direction: column; padding: 16px 24px 12px; }
.leitor:fullscreen .palco { flex: 1; height: auto; }
.zoom {
  width: calc(100vw - 48px); height: calc(100dvh - 48px); max-width: 1200px; max-height: none;
  padding: 0; border: 0; border-radius: 10px; background: var(--lgray); overflow: hidden;
}
.zoom::backdrop { background: rgba(15, 23, 42, .6); backdrop-filter: blur(3px); }
.zoom-barra { height: 56px; display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 0 12px 0 18px; background: var(--white); color: var(--text); font-size: .92rem; }
.zoom-barra div { display: flex; align-items: center; gap: 2px; }
.zoom-barra .icone { color: var(--slate); font-size: 1.2rem; }
.zoom-barra .icone:hover:not(:disabled) { background: var(--soft); color: var(--charcoal); }
.zoom-barra svg { fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
#zoom-nivel { min-width: 3.4em; text-align: center; font-size: .85rem; color: var(--gray); }
.zoom-conteudo { height: calc(100% - 56px); overflow: auto; padding: 24px; }
.zoom-conteudo img { max-width: none; margin: 0 auto; box-shadow: 0 8px 30px rgba(0, 0, 0, .15); }
.simbolos { position: absolute; width: 0; height: 0; overflow: hidden; }
@keyframes entrada { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: none; } }
@media (max-width: 760px) {
  .leitor { padding: 10px 6px 8px; border-radius: 8px; }
  .palco { height: min(calc((100vw - 120px) * 1.413 + 40px), 82vh); }
  .moldura { inset: 14px 30px 26px; }
  .seta { width: 26px; }
  .seta svg { width: 20px; height: 20px; }
  .seta.anterior { left: 2px; }
  .seta.proxima { right: 2px; }
  .rotulo-pagina, .dica { display: none; }
  .icone { width: 32px; height: 34px; padding: 6px; }
  .paginacao label { margin: 0 2px; }
  #primeira, #ultima { display: none; }
  .zoom { width: 100vw; height: 100dvh; max-width: 100vw; max-height: 100dvh; border-radius: 0; }
}
@media (prefers-reduced-motion: reduce) {
  .moldura { animation: none; }
  .moldura .stf__block { transition: none; }
}

.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }