/* ==========================================================================
   CodeForge Layout — Mobile-First
   Base styles target small screens (≤479px).
   min-width media queries layer on enhancements for larger viewports.
   All values reference design tokens from css/tokens.css.
   ========================================================================== */

/* --------------------------------------------------------------------------
   0. GLOBAL BOX MODEL
   -------------------------------------------------------------------------- */

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

html {
  /* Prevent horizontal overflow on small screens */
  overflow-x: hidden;
  /* Smooth scroll for in-page anchors */
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh; /* dynamic viewport height for mobile browsers */
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  font-weight: var(--fw-normal);
  line-height: var(--lh-normal);
  color: var(--text-primary);
  background-color: var(--bg-canvas);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  /* Respect safe areas on notched devices */
  padding-top: env(safe-area-inset-top);
  padding-bottom: env(safe-area-inset-bottom);
  padding-left: env(safe-area-inset-left);
  padding-right: env(safe-area-inset-right);
}

/* --------------------------------------------------------------------------
   1. BOOT SCREEN
   Full-viewport overlay shown during initialization.
   -------------------------------------------------------------------------- */

#boot-screen {
  position: fixed;
  inset: 0;
  z-index: var(--z-boot);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  background-color: var(--bg-canvas);
  color: var(--text-secondary);
  transition: opacity var(--dur-slow) var(--ease-out);
}

#boot-screen.is-hidden {
  opacity: 0;
  pointer-events: none;
}

/* Simple CSS-only spinner for the boot screen */
#boot-screen .spinner,
#boot-screen [data-spinner] {
  width: 2.5rem;
  height: 2.5rem;
  border: 3px solid var(--border-default);
  border-top-color: var(--color-primary);
  border-radius: var(--radius-full);
  animation: boot-spin 0.8s linear infinite;
}

@keyframes boot-spin {
  to { transform: rotate(360deg); }
}

/* --------------------------------------------------------------------------
   2. APP SHELL — Mobile Base (single column, stacked)
   -------------------------------------------------------------------------- */

#app-shell {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  min-height: 100dvh;
  width: 100%;
  opacity: 0;
  transition: opacity var(--dur-base) var(--ease-out);
}

#app-shell.is-visible {
  opacity: 1;
}

#app-shell[hidden] {
  display: none;
}

/* --------------------------------------------------------------------------
   3. HEADER — Mobile Base
   -------------------------------------------------------------------------- */

.app-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  height: var(--header-height);
  padding-inline: var(--space-3);
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--border-subtle);
  flex-shrink: 0;
}

.app-header__brand {
  font-size: var(--fs-md);
  font-weight: var(--fw-bold);
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.app-header__actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-inline-start: auto;
}

/* Hamburger / menu toggle — visible on mobile, hidden on desktop */
.app-header__menu-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: var(--touch-target-min);
  height: var(--touch-target-min);
  padding: 0;
  background: none;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  cursor: pointer;
  flex-shrink: 0;
}

.app-header__menu-toggle:hover,
.app-header__menu-toggle:focus-visible {
  background-color: var(--bg-surface-raised);
  border-color: var(--border-strong);
}

/* --------------------------------------------------------------------------
   4. SIDEBAR — Mobile Base (hidden off-canvas by default)
   -------------------------------------------------------------------------- */

.app-sidebar {
  position: fixed;
  top: var(--header-height);
  left: 0;
  bottom: 0;
  z-index: var(--z-sidebar);
  width: min(var(--sidebar-width), 85vw);
  background-color: var(--bg-surface);
  border-right: 1px solid var(--border-subtle);
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: var(--space-4) var(--space-3);
  transform: translateX(-100%);
  transition: transform var(--dur-base) var(--ease-out);
}

/* When the sidebar is open on mobile (toggled via JS class) */
.app-sidebar.is-open {
  transform: translateX(0);
}

/* Backdrop overlay behind the sidebar on mobile */
.sidebar-backdrop {
  position: fixed;
  inset: 0;
  z-index: calc(var(--z-sidebar) - 1);
  background-color: rgba(0, 0, 0, 0.5);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--dur-base) var(--ease-out);
}

.sidebar-backdrop.is-visible {
  opacity: 1;
  pointer-events: auto;
}

/* --------------------------------------------------------------------------
   5. MAIN CONTENT — Mobile Base
   -------------------------------------------------------------------------- */

.app-main {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  min-height: 0; /* allow flex children to shrink */
  width: 100%;
  overflow: hidden;
}

.app-main__content {
  flex: 1 1 auto;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: var(--space-4) var(--space-3);
  width: 100%;
  max-width: var(--chat-max-width);
  margin-inline: auto;
}

/* --------------------------------------------------------------------------
   6. COMMAND BAR — Mobile Base
   -------------------------------------------------------------------------- */

.command-bar {
  position: sticky;
  bottom: 0;
  z-index: var(--z-sticky);
  display: flex;
  align-items: flex-end;
  gap: var(--space-2);
  min-height: var(--command-bar-min-h);
  padding: var(--space-3);
  background-color: var(--bg-surface);
  border-top: 1px solid var(--border-subtle);
  flex-shrink: 0;
}

.command-bar__input {
  flex: 1 1 auto;
  min-height: var(--touch-target-min);
  padding: var(--space-2) var(--space-3);
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  line-height: var(--lh-normal);
  color: var(--text-primary);
  background-color: var(--bg-surface-raised);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  resize: none;
  outline: none;
  transition: border-color var(--dur-fast) var(--ease-out),
              box-shadow var(--dur-fast) var(--ease-out);
}

.command-bar__input::placeholder {
  color: var(--text-muted);
}

.command-bar__input:focus {
  border-color: var(--border-focus);
  box-shadow: var(--shadow-focus);
}

.command-bar__send {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: var(--touch-target-min);
  min-height: var(--touch-target-min);
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-sans);
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  color: var(--text-inverse);
  background-color: var(--color-primary);
  border: none;
  border-radius: var(--radius-lg);
  cursor: pointer;
  flex-shrink: 0;
  transition: background-color var(--dur-fast) var(--ease-out);
}

.command-bar__send:hover,
.command-bar__send:focus-visible {
  background-color: var(--color-primary-hover);
}

.command-bar__send:active {
  background-color: var(--color-primary-active);
}

.command-bar__send:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* --------------------------------------------------------------------------
   7. STATUS BAR / FOOTER — Mobile Base
   -------------------------------------------------------------------------- */

.status-bar {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  height: var(--status-bar-height);
  padding-inline: var(--space-3);
  font-size: var(--fs-xs);
  color: var(--text-muted);
  background-color: var(--bg-surface);
  border-top: 1px solid var(--border-subtle);
  flex-shrink: 0;
  overflow: hidden;
  white-space: nowrap;
}

.status-bar__item {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
}

.status-bar__spacer {
  flex: 1 1 auto;
}

/* --------------------------------------------------------------------------
   8. UTILITY CLASSES
   -------------------------------------------------------------------------- */

.is-hidden {
  display: none !important;
}

.is-visible {
  /* Intentionally empty — used as a state hook for transitions.
     Visibility is controlled by removing [hidden] or .is-hidden. */
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* --------------------------------------------------------------------------
   9. REDUCED MOTION
   -------------------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ==========================================================================
   RESPONSIVE ENHANCEMENTS — min-width (mobile-first progression)
   ========================================================================== */

/* --------------------------------------------------------------------------
   ≥ 480px  —  Large phone / small tablet
   -------------------------------------------------------------------------- */
@media (min-width: 480px) {
  .app-header {
    padding-inline: var(--space-4);
  }

  .app-main__content {
    padding: var(--space-6) var(--space-4);
  }

  .command-bar {
    padding: var(--space-3) var(--space-4);
  }

  .status-bar {
    padding-inline: var(--space-4);
  }
}

/* --------------------------------------------------------------------------
   ≥ 768px  —  Tablet
   Sidebar becomes a persistent narrow rail; main content shifts right.
   -------------------------------------------------------------------------- */
@media (min-width: 768px) {
  /* Shell becomes a two-column layout */
  #app-shell {
    display: grid;
    grid-template-columns: var(--sidebar-collapsed-width) 1fr;
    grid-template-rows: var(--header-height) 1fr var(--status-bar-height);
    grid-template-areas:
      "header  header"
      "sidebar main"
      "footer  footer";
  }

  .app-header {
    grid-area: header;
    padding-inline: var(--space-6);
  }

  /* Hide the hamburger — sidebar is now always visible */
  .app-header__menu-toggle {
    display: none;
  }

  /* Sidebar: persistent collapsed rail */
  .app-sidebar {
    grid-area: sidebar;
    position: static;
    width: var(--sidebar-collapsed-width);
    transform: none;
    padding: var(--space-4) var(--space-2);
    border-right: 1px solid var(--border-subtle);
    overflow-y: auto;
  }

  /* Backdrop no longer needed */
  .sidebar-backdrop {
    display: none;
  }

  .app-main {
    grid-area: main;
  }

  .app-main__content {
    padding: var(--space-6);
  }

  .command-bar {
    padding: var(--space-4) var(--space-6);
  }

  .status-bar {
    grid-area: footer;
    padding-inline: var(--space-6);
  }
}

/* --------------------------------------------------------------------------
   ≥ 1024px  —  Desktop
   Sidebar expands to full width; comfortable spacing throughout.
   -------------------------------------------------------------------------- */
@media (min-width: 1024px) {
  #app-shell {
    grid-template-columns: var(--sidebar-width) 1fr;
  }

  .app-header {
    padding-inline: var(--space-8);
  }

  .app-sidebar {
    width: var(--sidebar-width);
    padding: var(--space-6) var(--space-4);
  }

  .app-main__content {
    padding: var(--space-8);
  }

  .command-bar {
    padding: var(--space-4) var(--space-8);
  }

  .status-bar {
    padding-inline: var(--space-8);
  }
}

/* --------------------------------------------------------------------------
   ≥ 1440px  —  Wide desktop
   Cap the main content width for readability.
   -------------------------------------------------------------------------- */
@media (min-width: 1440px) {
  .app-main__content {
    max-width: calc(var(--chat-max-width) + 4rem);
  }
}