/* ============================================================
   layout.css — Estrutura macro da página
   Cabeçalho, sidebar de tópicos, área principal, índice lateral
   do tópico, barra de progresso de leitura e rodapé.
   ============================================================ */

/* ---------- Cabeçalho ---------- */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background-color: var(--color-header-bg);
  -webkit-backdrop-filter: saturate(1.4) blur(10px);
  backdrop-filter: saturate(1.4) blur(10px);
  color: var(--color-header-text);
  border-bottom: var(--border-width) solid var(--color-border);
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: 0 var(--space-5);
}

.header-brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: inherit;
  font-weight: 700;
  font-size: var(--font-size-md);
  letter-spacing: var(--tracking-tight);
  white-space: nowrap;
}

.header-brand:hover { text-decoration: none; }
.header-brand .brand-mark { display: block; flex-shrink: 0; }
.header-brand .brand-code {
  font-family: var(--font-family-mono);
  font-size: 0.62rem;
  letter-spacing: 0.14em;
  color: var(--color-text-muted);
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--radius-pill);
  padding: 0.1rem 0.5rem;
}

.header-spacer { flex: 1; }

.header-nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.header-nav a {
  color: var(--color-text-muted);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
}

.header-nav a:hover,
.header-nav a.is-active {
  background-color: var(--color-bg-sunken);
  color: var(--color-text);
  text-decoration: none;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* ---------- Barra de progresso de leitura ---------- */
.readbar {
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  height: 3px;
  z-index: 90;
  background: transparent;
  pointer-events: none;
}
.readbar > i {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--color-brand), var(--color-accent));
  transition: width 90ms linear;
}

/* ---------- Casca: sidebar + conteúdo ---------- */
.app-shell {
  display: flex;
  min-height: calc(100vh - var(--header-height));
}

/* ---------- Sidebar (trilha de tópicos) ---------- */
.app-sidebar {
  width: var(--sidebar-width);
  flex-shrink: 0;
  background-color: var(--color-sidebar-bg);
  border-right: var(--border-width) solid var(--color-border);
  padding: var(--space-5) var(--space-4);
  overflow-y: auto;
  position: sticky;
  top: var(--header-height);
  height: calc(100vh - var(--header-height));
}

.sidebar-title {
  font-family: var(--font-family-mono);
  font-size: 0.64rem;
  text-transform: uppercase;
  letter-spacing: var(--tracking-label);
  color: var(--color-text-muted);
  margin: var(--space-2) var(--space-2) var(--space-3);
}

.sidebar-progress { margin-bottom: var(--space-4); }

/* trilha com "espinha" conectando os nós */
.topic-list {
  list-style: none;
  padding: 0;
  margin: 0;
  position: relative;
}
.topic-list::before {
  content: "";
  position: absolute;
  left: 19px;
  top: 14px;
  bottom: 14px;
  width: 2px;
  background: var(--color-line-soft);
}

.topic-list li { margin-bottom: 2px; }

.topic-link {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.topic-link:hover {
  background-color: var(--color-bg-sunken);
  color: var(--color-text);
  text-decoration: none;
}

.topic-link.is-active {
  background-color: var(--color-brand-soft);
  color: var(--color-text);
  font-weight: 600;
}

.topic-link .topic-number {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background-color: var(--color-bg-elevated);
  border: 2px solid var(--color-border);
  font-family: var(--font-family-mono);
  font-size: 0.62rem;
  font-weight: 700;
  color: var(--color-text-muted);
  position: relative;
  z-index: 1;
}

.topic-link.is-active .topic-number {
  border-color: var(--color-brand);
  color: var(--color-link);
}

.topic-link.is-done .topic-number {
  background-color: var(--color-success);
  border-color: var(--color-success);
  color: #fff;
}

.topic-link .topic-label {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ---------- Área principal ---------- */
.app-view {
  flex: 1;
  padding: var(--space-6) var(--space-5);
  min-width: 0;
}

.view-container {
  max-width: var(--content-max-width);
  margin: 0 auto;
}

/* ---------- Layout de 3 zonas do tópico ---------- */
.topic-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) var(--toc-width);
  gap: var(--space-7);
  max-width: calc(var(--reading-max) + var(--toc-width) + var(--space-7));
  margin: 0 auto;
  align-items: start;
}

.topic-main { min-width: 0; }
.topic-main > * { max-width: var(--reading-max); }

.topic-toc {
  position: sticky;
  top: calc(var(--header-height) + var(--space-5));
  align-self: start;
}
.topic-toc .toc-title {
  font-family: var(--font-family-mono);
  font-size: 0.64rem;
  letter-spacing: var(--tracking-label);
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-3);
}
.topic-toc a {
  display: block;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  padding: var(--space-1) 0 var(--space-1) var(--space-3);
  border-left: 2px solid var(--color-border);
  line-height: 1.35;
}
.topic-toc a:hover { color: var(--color-text); text-decoration: none; }
.topic-toc a.is-active {
  color: var(--color-link);
  border-left-color: var(--color-brand);
  font-weight: 600;
}

/* ---------- Rodapé ---------- */
.app-footer {
  border-top: var(--border-width) solid var(--color-border);
  padding: var(--space-4) var(--space-5);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-align: center;
}

/* ---------- Responsivo ---------- */
@media (max-width: 1180px) {
  .topic-layout { grid-template-columns: minmax(0, 1fr); }
  .topic-toc { display: none; }
}

@media (max-width: 900px) {
  .app-shell { flex-direction: column; }

  .app-sidebar {
    width: 100%;
    height: auto;
    position: static;
    border-right: none;
    border-bottom: var(--border-width) solid var(--color-border);
  }

  .topic-list::before { display: none; }

  .header-nav { display: none; }
}