/* ================================================================
   css/layout.css — Virtual Lab TJKT
   Struktur tata letak utama: Header, Navigasi Tab, Main, Footer,
   Tombol global, dan Panel Tab.
   ================================================================ */

/* ----------------------------------------------------------------
   HEADER
   ---------------------------------------------------------------- */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 14, 26, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-xl);
  max-width: 1280px;
  margin: 0 auto;
  gap: var(--space-md);
}

.header-brand {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  flex: 1;
  min-width: 0;
}

.brand-icon {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
  animation: iconPulse 3s ease-in-out infinite;
}

.brand-label {
  display: block;
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 2px;
}

.brand-title {
  font-size: clamp(0.8rem, 2vw, 1rem);
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.2;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ----------------------------------------------------------------
   HAMBURGER (mobile)
   ---------------------------------------------------------------- */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
  flex-shrink: 0;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
  transition: var(--transition);
}

/* ----------------------------------------------------------------
   NAVIGASI TAB
   ---------------------------------------------------------------- */
.tab-nav {
  display: flex;
  padding: 0 var(--space-xl);
  max-width: 1280px;
  margin: 0 auto;
  gap: var(--space-xs);
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

.tab-nav::-webkit-scrollbar { display: none; }

.tab-btn {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--text-secondary);
  font-family: var(--font-main);
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  transition: var(--transition);
  position: relative;
  margin-bottom: -1px;
}

.tab-btn svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

.tab-btn:hover {
  color: var(--text-primary);
  background: var(--accent-glow);
}

.tab-btn.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
  font-weight: 600;
}

/* Tombol Petunjuk — didorong ke kanan */
.tab-btn-help {
  margin-left: auto;
  color: var(--accent-dim);
  border-left: 1px solid var(--border);
  padding-left: var(--space-lg);
}

.tab-btn-help:hover { color: var(--accent); }

/* ----------------------------------------------------------------
   MAIN CONTENT
   ---------------------------------------------------------------- */
.app-main {
  max-width: 1280px;
  margin: 0 auto;
  padding: var(--space-xl);
  min-height: calc(100vh - 200px);
}

/* ----------------------------------------------------------------
   TAB PANEL
   ---------------------------------------------------------------- */
.tab-panel {
  animation: fadeIn 0.3s ease;
}

.panel-intro {
  margin-bottom: var(--space-xl);
}

.panel-title {
  font-size: clamp(1.3rem, 3vw, 1.8rem);
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
  padding-left: var(--space-md);
  border-left: 3px solid var(--accent);
}

.panel-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  padding-left: var(--space-md);
}

/* ----------------------------------------------------------------
   TOMBOL GLOBAL (komponen reusable)
   ---------------------------------------------------------------- */
.btn-primary,
.btn-secondary {
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-md);
  font-family: var(--font-main);
  font-size: 0.85rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  letter-spacing: 0.02em;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-dim), var(--accent));
  color: var(--bg-base);
  box-shadow: 0 4px 15px rgba(0, 240, 255, 0.3);
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(0, 240, 255, 0.4);
}

.btn-primary:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.btn-secondary {
  background: var(--bg-elevated);
  color: var(--text-secondary);
  border: 1px solid var(--border);
}

.btn-secondary:hover:not(:disabled) {
  border-color: var(--border-active);
  color: var(--text-primary);
}

.btn-secondary:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn-large {
  padding: var(--space-md) var(--space-xl);
  font-size: 1rem;
}

/* ----------------------------------------------------------------
   FOOTER
   ---------------------------------------------------------------- */
.app-footer {
  border-top: 1px solid var(--border);
  padding: var(--space-lg) var(--space-xl);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.78rem;
}

.footer-sub {
  margin-top: var(--space-xs);
  font-size: 0.7rem;
  opacity: 0.6;
}