/* ═══════════════════════════════════════════════════════════
   layout.css — Header, navegação, grid, estrutura de página
═══════════════════════════════════════════════════════════ */

/* ── APP HEADER ── */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  background: var(--header-bg);
  border-bottom: 1px solid var(--border-subtle);
  backdrop-filter: var(--header-blur);
  -webkit-backdrop-filter: var(--header-blur);
  display: flex;
  align-items: center;
  padding: 0 var(--space-5);
  gap: var(--space-4);
}

.header-left {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
}

.app-logo {
  font-family: var(--font-serif);
  font-size: 20px;
  color: var(--text-primary);
  letter-spacing: -0.03em;
  white-space: nowrap;
}
.app-logo span {
  color: var(--accent);
  font-style: italic;
}

/* ── NAV TABS ── */
.nav-tabs {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex: 1;
  overflow-x: auto;
  scrollbar-width: none;
  padding: 0 var(--space-2);
}
.nav-tabs::-webkit-scrollbar { display: none; }

.nav-tab {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: 6px 14px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 400;
  border-radius: var(--radius-md);
  white-space: nowrap;
  transition: all var(--transition);
  flex-shrink: 0;
}
.nav-tab svg { flex-shrink: 0; }
.nav-tab:hover { color: var(--text-secondary); background: var(--bg-raised); }
.nav-tab.active {
  color: var(--text-primary);
  background: var(--bg-overlay);
  font-weight: 500;
}
.nav-tab.active svg { color: var(--accent); }

/* ── HEADER ACTIONS ── */
.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

/* ── THEME TOGGLE ── */
.theme-toggle {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-pill);
  background: var(--bg-raised);
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 12px;
  font-family: var(--font-sans);
  font-weight: 500;
  white-space: nowrap;
  transition: all var(--transition);
}
.theme-toggle:hover {
  border-color: var(--border-strong);
  color: var(--text-primary);
}
.theme-toggle .icon-sun,
.theme-toggle .icon-moon { display: none; }
[data-theme="dark"]  .theme-toggle .icon-moon { display: block; }
[data-theme="light"] .theme-toggle .icon-sun  { display: block; }

/* ── MOBILE MENU BUTTON ── */
.mobile-menu-btn {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  background: transparent;
  cursor: pointer;
  padding: 0;
  flex-shrink: 0;
}
.mobile-menu-btn span {
  display: block;
  width: 16px;
  height: 1.5px;
  background: var(--text-secondary);
  border-radius: 2px;
  transition: all var(--transition);
}
.mobile-menu-btn.open span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.mobile-menu-btn.open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.mobile-menu-btn.open span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

/* ── MAIN ── */
.main {
  max-width: 1300px;
  margin: 0 auto;
  padding: var(--space-6) var(--space-5);
}

/* ── GRIDS GENÉRICOS ── */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-4); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-4); }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-4); }
.grid-auto { display: grid; grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); gap: var(--space-3); }

/* ── SIMULADOR LAYOUT ── */
.sim-layout {
  display: grid;
  grid-template-columns: 290px 1fr;
  gap: var(--space-5);
  align-items: start;
}

/* ── CHECKER LAYOUT ── */
.checker-layout {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: var(--space-5);
  align-items: start;
}

/* ── STACK ── */
.stack { display: flex; flex-direction: column; }
.stack-2 { gap: var(--space-2); }
.stack-3 { gap: var(--space-3); }
.stack-4 { gap: var(--space-4); }
.stack-5 { gap: var(--space-5); }
.stack-6 { gap: var(--space-6); }

/* ── FLEX ── */
.flex        { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.flex-between{ display: flex; align-items: center; justify-content: space-between; }
.gap-1 { gap: var(--space-1); }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }