/* ==========================================================================
   AI Studio — Shell Layout  ·  3-Column Grid + Responsive Breakpoints
   Uses design tokens from variables.css exclusively (no hardcoded colors).
   ========================================================================== */

/* --- Reset (studio scope) --- */
.studio-shell *, .studio-shell *::before, .studio-shell *::after {
  box-sizing: border-box; margin: 0; padding: 0;
}

/* --- Shell Layout (desktop >= 1024px) --- */
.studio-shell {
  display: grid;
  grid-template-columns: 240px 1fr 320px;
  grid-template-rows: var(--header-height) 1fr;
  grid-template-areas:
    "header  header   header"
    "sidebar workspace chat";
  height: 100vh;
  height: 100dvh;
  background: var(--color-base);
  color: var(--color-text);
  font-family: var(--font-ui);
  font-size: var(--text-base);
  overflow: hidden;
  transition: grid-template-columns var(--transition-medium);
}

/* --- Collapsed chat state --- */
.studio-shell.chat-collapsed {
  grid-template-columns: 240px 1fr 40px;
}

/* --- Header --- */
.studio-header {
  grid-area: header;
  display: flex;
  align-items: center;
  height: var(--header-height);
  padding: 0 var(--spacing-md);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-panel);
  gap: var(--spacing-md);
}
.studio-header-left { display: flex; align-items: center; flex: 0 0 auto; }
.studio-header-center { flex: 1; text-align: center; }
.studio-header-right { display: flex; align-items: center; flex: 0 0 auto; }
.studio-back-link {
  display: flex; align-items: center; gap: var(--spacing-sm);
  color: var(--color-text-muted); text-decoration: none;
  font-size: var(--text-sm);
  transition: color var(--transition-fast);
}
.studio-back-link:hover { color: var(--color-text); }
.studio-title {
  font-size: var(--text-md); font-weight: 600;
  color: var(--color-text-bright);
}

/* --- Skip link (accessibility) --- */
.skip-link {
  position: absolute;
  top: -100px; left: var(--spacing-sm);
  z-index: 300;
  background: var(--accent);
  color: #fff;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  text-decoration: none;
  transition: top var(--transition-fast);
}
.skip-link:focus {
  top: var(--spacing-sm);
}

/* --- Sidebar --- */
.studio-sidebar {
  grid-area: sidebar;
  background: var(--color-panel);
  border-right: 1px solid var(--color-border);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}
.studio-sidebar-section { flex: 0 0 auto; }
.studio-sidebar-heading {
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding: var(--spacing-lg) var(--spacing-md) var(--spacing-sm) var(--spacing-md);
  font-weight: 600;
}
.studio-nav { display: flex; flex-direction: column; }
.studio-nav-item {
  display: flex; align-items: center;
  gap: var(--spacing-sm);
  height: 40px;
  padding: 0 var(--spacing-md);
  color: var(--color-text);
  cursor: pointer;
  border-left: 3px solid transparent;
  background: none; border-right: none; border-top: none; border-bottom: none;
  font-family: var(--font-ui);
  font-size: var(--text-base);
  text-decoration: none;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}
.studio-nav-item:hover { background: var(--color-surface); }
.studio-nav-item.active {
  border-left-color: var(--accent);
  background: rgba(88,166,255,0.08);
  color: var(--color-text-bright);
}
.studio-nav-icon {
  flex: 0 0 18px; width: 18px; height: 18px;
  display: flex; align-items: center; justify-content: center;
}
.studio-nav-label {
  font-size: var(--text-base);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.studio-sidebar-footer {
  margin-top: auto;
  padding: var(--spacing-md);
  border-top: 1px solid var(--color-border);
}
.studio-sidebar-back {
  display: flex; align-items: center; gap: var(--spacing-sm);
  color: var(--color-text-muted); text-decoration: none;
  font-size: var(--text-sm);
  transition: color var(--transition-fast);
}
.studio-sidebar-back:hover { color: var(--color-text); }

/* --- Workspace --- */
.studio-workspace {
  grid-area: workspace;
  overflow-y: auto;
  background: var(--color-base);
}
.studio-workspace-content {
  padding: var(--spacing-xl);
  min-height: 100%;
}
.studio-empty-state {
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  min-height: 60vh; text-align: center;
}
.studio-empty-heading {
  font-size: var(--text-lg); font-weight: 600;
  color: var(--color-text-bright);
  margin-bottom: var(--spacing-md);
}
.studio-empty-body {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  max-width: 400px; line-height: 1.5;
}

/* --- Chat Panel --- */
.studio-chat {
  grid-area: chat;
  background: var(--color-panel);
  border-left: 1px solid var(--color-border);
  display: flex; flex-direction: column;
  overflow: hidden;
}
.studio-chat-header {
  height: var(--header-height);
  display: flex; align-items: center;
  padding: 0 var(--spacing-md);
  border-bottom: 1px solid var(--color-border);
  gap: var(--spacing-sm);
  flex: 0 0 auto;
}
.studio-chat-title {
  font-size: var(--text-md); font-weight: 600;
  color: var(--color-text-bright);
}
.studio-chat-context {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-left: var(--spacing-sm); flex: 1;
}
.studio-chat-toggle {
  width: 32px; height: 32px;
  display: flex; align-items: center; justify-content: center;
  background: none; border: none;
  color: var(--color-text-muted); cursor: pointer;
  border-radius: var(--radius-xs);
  transition: background var(--transition-fast);
  margin-left: auto;
}
.studio-chat-toggle:hover {
  background: var(--color-surface);
  color: var(--color-text);
}
.studio-chat-body {
  flex: 1; overflow-y: auto;
  padding: var(--spacing-md);
}
.studio-chat-empty {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  text-align: center;
  padding: var(--spacing-xl) var(--spacing-md);
}
.studio-chat-input {
  display: flex; gap: var(--spacing-sm);
  padding: var(--spacing-md);
  border-top: 1px solid var(--color-border);
  flex: 0 0 auto;
}
.studio-chat-field {
  flex: 1;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--color-text);
  font-family: var(--font-ui);
  font-size: var(--text-base);
  outline: none;
}
.studio-chat-field:focus { border-color: var(--accent); }
.studio-chat-send {
  width: 36px; height: 36px;
  display: flex; align-items: center; justify-content: center;
  background: var(--accent); border: none;
  border-radius: var(--radius-sm);
  color: #fff; cursor: pointer;
  transition: opacity var(--transition-fast);
}
.studio-chat-send:hover { opacity: 0.85; }

/* --- Collapsed chat --- */
.studio-shell.chat-collapsed .studio-chat-body,
.studio-shell.chat-collapsed .studio-chat-input,
.studio-shell.chat-collapsed .studio-chat-title,
.studio-shell.chat-collapsed .studio-chat-context { display: none; }
.studio-shell.chat-collapsed .studio-chat-header {
  justify-content: center; border-bottom: none;
}
.studio-shell.chat-collapsed .studio-chat-toggle svg {
  transform: rotate(180deg);
}

/* --- Chat FAB (tablet only) --- */
.studio-chat-fab {
  position: fixed;
  bottom: var(--spacing-lg); right: var(--spacing-lg);
  width: 48px; height: 48px;
  border-radius: 50%;
  background: var(--accent); color: #fff;
  border: none; display: none;
  z-index: 200; cursor: pointer;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}

/* --- Responsive: Tablet (max-width: 1023px) --- */
@media (max-width: 1023px) {
  .studio-shell {
    grid-template-columns: 240px 1fr;
    grid-template-areas:
      "header   header"
      "sidebar  workspace";
  }
  .studio-chat {
    position: fixed;
    right: 0; top: 0;
    width: 320px;
    height: 100vh; height: 100dvh;
    z-index: 300;
    transform: translateX(100%);
    transition: transform var(--transition-medium);
  }
  .studio-chat.open { transform: translateX(0); }
  .studio-chat-fab {
    display: flex; align-items: center; justify-content: center;
  }
  .studio-shell.chat-collapsed { grid-template-columns: 240px 1fr; }
  .studio-chat-overlay {
    position: fixed; inset: 0;
    background: var(--color-overlay);
    z-index: 299;
    opacity: 0; pointer-events: none;
    transition: opacity var(--transition-medium);
  }
  .studio-chat-overlay.visible { opacity: 1; pointer-events: auto; }
}

/* --- Responsive: Mobile (max-width: 767px) --- */
@media (max-width: 767px) {
  .studio-shell {
    grid-template-columns: 1fr;
    grid-template-rows: var(--header-height) 1fr 56px;
    grid-template-areas:
      "header"
      "workspace"
      "bottomnav";
  }
  .studio-sidebar { display: none; }
  .studio-sidebar.active {
    display: flex;
    position: fixed; inset: 0;
    top: var(--header-height); bottom: 56px;
    z-index: 300; width: 100%;
  }
  .studio-chat {
    display: none;
    position: fixed; inset: 0;
    top: var(--header-height); bottom: 56px;
    width: 100%; z-index: 300;
  }
  .studio-chat.active { display: flex; }
  .studio-chat-fab { display: none; }
  .studio-shell.chat-collapsed { grid-template-columns: 1fr; }
  .studio-header .studio-back-link span { display: none; }
  .studio-bottomnav {
    grid-area: bottomnav;
    display: flex;
    background: var(--color-panel);
    border-top: 1px solid var(--color-border);
    z-index: 200;
  }
  .studio-bottomnav-item {
    flex: 1;
    display: flex; flex-direction: column;
    align-items: center; justify-content: center;
    gap: 2px;
    padding: var(--spacing-sm) 0;
    color: var(--color-text-muted);
    background: none; border: none;
    cursor: pointer;
    font-family: var(--font-ui);
    font-size: var(--text-sm);
    transition: color var(--transition-fast);
  }
  .studio-bottomnav-item[aria-selected="true"] { color: var(--accent); }
  .studio-bottomnav-item:hover { color: var(--color-text); }
  /* Override the desktop hide rule — must be inside the media query to win cascade */
  .studio-bottomnav { display: flex !important; }
}

/* --- Theme toggle button --- */
.studio-theme-toggle {
  display: flex; align-items: center; justify-content: center;
  width: 32px; height: 32px;
  background: none; border: 1px solid var(--color-border);
  border-radius: var(--radius-sm, 6px);
  color: var(--color-text-muted);
  cursor: pointer;
  transition: color var(--transition-fast), border-color var(--transition-fast);
  margin-right: var(--spacing-sm, 8px);
}
.studio-theme-toggle:hover {
  color: var(--color-text);
  border-color: var(--color-border-strong);
}

/* --- Light theme overrides for Studio --- */
body.light-theme .studio-shell {
  background: var(--color-base);
  color: var(--color-text);
}
body.light-theme .studio-header {
  background: var(--color-panel);
  border-bottom-color: var(--color-border);
}
body.light-theme .studio-sidebar {
  background: var(--color-panel);
  border-right-color: var(--color-border);
}
body.light-theme .studio-workspace {
  background: var(--color-base);
}
body.light-theme .studio-chat {
  background: var(--color-panel);
  border-left-color: var(--color-border);
}
body.light-theme .studio-chat-header {
  border-bottom-color: var(--color-border);
}
body.light-theme .studio-chat-input {
  border-top-color: var(--color-border);
}
body.light-theme .studio-chat-field {
  background: var(--color-surface);
  color: var(--color-text);
  border-color: var(--color-border);
}
body.light-theme .studio-nav-item:hover {
  background: var(--color-surface);
}
body.light-theme .studio-nav-item.active {
  background: rgba(0,196,167,0.08);
}
body.light-theme .studio-sidebar-heading {
  color: var(--color-text-muted);
}
body.light-theme .studio-empty-body {
  color: var(--color-text-muted);
}
body.light-theme .studio-bottomnav {
  background: var(--color-panel);
  border-top-color: var(--color-border);
}
body.light-theme .studio-theme-toggle {
  color: var(--color-text-muted);
  border-color: var(--color-border);
}
body.light-theme .studio-theme-toggle:hover {
  color: var(--color-accent);
}