*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  height: 100%;
  overflow: hidden;
  font-family: var(--font-family);
  font-size: var(--font-size-md);
  line-height: var(--line-height);
  color: var(--text-primary);
  background: var(--bg-app);
}

.md-app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
}

.md-main {
  display: flex;
  flex: 1;
  overflow: hidden;
  position: relative;
}

.md-content {
  flex: 1;
  position: relative;
  overflow-y: auto;
  overflow-x: hidden;
  background: var(--bg-app);
}

/* Shared scrollbar styling — thin track with subtle thumb */
.md-content::-webkit-scrollbar,
.md-sidebar__body::-webkit-scrollbar,
.md-scripts__body::-webkit-scrollbar {
  width: 7px;
}

.md-content::-webkit-scrollbar-track,
.md-sidebar__body::-webkit-scrollbar-track,
.md-scripts__body::-webkit-scrollbar-track {
  background: transparent;
}

.md-content::-webkit-scrollbar-thumb,
.md-sidebar__body::-webkit-scrollbar-thumb,
.md-scripts__body::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 4px;
}

.md-content::-webkit-scrollbar-thumb:hover,
.md-sidebar__body::-webkit-scrollbar-thumb:hover,
.md-scripts__body::-webkit-scrollbar-thumb:hover {
  background: var(--border-color-strong);
}

/* Skip navigation link — WCAG 2.4.1 */
.md-skip-link {
  position: absolute;
  top: -100%;
  left: var(--spacing-md);
  z-index: 10000;
  padding: var(--spacing-sm) var(--spacing-lg);
  background: var(--color-primary);
  color: var(--text-inverse);
  font-weight: 700;
  font-size: var(--font-size-sm);
  text-decoration: none;
  border-radius: 0 0 var(--border-radius-sm) var(--border-radius-sm);
}

.md-skip-link:focus {
  top: 0;
}

/* WCAG 2.4.7 — Visible focus indicators */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

button:focus-visible,
input:focus-visible,
select:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 1px;
}

:focus:not(:focus-visible) {
  outline: none;
}

/* Utility */
.hidden {
  display: none !important;
}

/* Notification toast */
.md-toast {
  position: fixed;
  bottom: var(--spacing-xl);
  right: var(--spacing-xl);
  background-color: var(--brand-red);
  color: white;
  padding: 12px 20px;
  font-weight: 700;
  font-size: var(--font-size-sm);
  text-transform: uppercase;
  letter-spacing: 1px;
  z-index: 3000;
  box-shadow: var(--shadow-md);
  border-radius: var(--border-radius-sm);
  animation: md-toast-in 0.3s ease-out;
}

@keyframes md-toast-in {
  from { opacity: 0; transform: translateX(20px); }
  to { opacity: 1; transform: translateX(0); }
}

/* Respect user motion preferences */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}

/* Mobile layout */
@media (max-width: 768px) {
  .md-main {
    flex-direction: column;
  }

  .md-content {
    flex: 1;
    min-height: 0;
  }

  /* Timeline container: remove excess top spacing */
  .md-timeline {
    padding-top: 0;
  }
}