*, *::before, *::after {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  overflow: hidden;
  background: #003366;
}

#tab-bar {
  display: flex;
  align-items: center;
  height: 48px;
  background: #003366;
  padding: 0 8px;
  gap: 4px;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
}

.tab-btn {
  height: 36px;
  padding: 0 20px;
  border: none;
  border-radius: 6px 6px 0 0;
  background: rgba(255, 255, 255, 0.15);
  color: rgba(255, 255, 255, 0.75);
  font-size: 14px;
  font-weight: 600;
  font-family: system-ui, -apple-system, sans-serif;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  letter-spacing: 0.3px;
}

.tab-btn:hover {
  background: rgba(255, 255, 255, 0.25);
  color: #ffffff;
}

.tab-btn.active {
  background: #ffffff;
  color: #003366;
}

.tab-btn:focus-visible {
  outline: 2px solid #ffcc00;
  outline-offset: 2px;
}

#iframe-container {
  position: fixed;
  top: 48px;
  left: 0;
  right: 0;
  bottom: 0;
}

#iframe-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
}