/* ============================================================
   PHONLAB — Layout
   Three-column grid: Left sidebar | Fluid main | Right sidebar
   No colours — structure only. All colours via tokens.css.
   ============================================================ */

/* ── Reset + Base ────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  height: 100%;
  overflow: hidden;
  font-family: var(--font-base);
  font-size: var(--text-md);
  background: var(--body-bg);
  color: var(--body-color);
  -webkit-font-smoothing: antialiased;
}

/* ── Fixed Header ────────────────────────────────────────── */
#appHeader {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  z-index: var(--z-header);
  display: flex;
  align-items: center;
  background: var(--header-bg);
  border-bottom: 1px solid var(--header-border);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.header-inner {
  width: 100%;
  padding: 0 var(--gap-md);
  display: flex;
  align-items: center;
  gap: var(--gap-md);
}

.header-brand {
  display: flex;
  align-items: baseline;
  gap: var(--gap-sm);
  flex-shrink: 0;
  font-size: var(--text-lg);
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.3px;
}

.header-brand__label {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  color: var(--accent-light);
  background: var(--accent-subtle);
  border: 1px solid var(--accent-border);
  border-radius: 4px;
  padding: 2px 6px;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: var(--gap-xs);
  flex: 1;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  margin-left: auto;
  flex-shrink: 0;
}

.header-breadcrumb {
  font-size: var(--text-sm);
  color: var(--text-muted);
  margin-left: var(--gap-sm);
}

.header-breadcrumb strong {
  color: var(--text-secondary);
  font-weight: 500;
}

/* ── Main Layout — three columns ─────────────────────────── */
.app-layout {
  display: flex;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  overflow: hidden;
}

/* ── Left Sidebar ────────────────────────────────────────── */
.sidebar-left {
  width: var(--sidebar-width);
  flex-shrink: 0;
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--sidebar-border);
}

.sidebar-left__section {
  padding: var(--gap-md) var(--gap-sm) var(--gap-sm);
}

.sidebar-left__label {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  color: var(--text-label);
  padding: var(--gap-sm) var(--gap-sm) var(--gap-xs);
}

.sidebar-left__item {
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  width: 100%;
  padding: 7px var(--gap-sm);
  border-radius: 8px;
  border: 1px solid transparent;
  background: transparent;
  color: var(--text-secondary);
  font-size: var(--text-sm);
  font-weight: 500;
  cursor: pointer;
  text-align: left;
  transition: background var(--t-fast), color var(--t-fast);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.sidebar-left__item:hover {
  background: var(--sidebar-item-hover);
  color: var(--text-primary);
}

.sidebar-left__item.active {
  background: var(--sidebar-item-active-bg);
  border-color: var(--sidebar-item-active-border);
  color: var(--sidebar-item-active-color);
}

.sidebar-left__item .icon {
  font-size: 13px;
  width: 16px;
  text-align: center;
  flex-shrink: 0;
}

.sidebar-left__badge {
  margin-left: auto;
  min-width: 18px;
  height: 18px;
  border-radius: 9px;
  background: rgba(239,68,68,0.85);
  color: #fff;
  font-size: 10px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 4px;
  flex-shrink: 0;
}

/* ── Main Content ────────────────────────────────────────── */
.main-content {
  flex: 1;
  min-width: 0;
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
}

.main-inner {
  flex: 1;
  padding: 0 var(--gap-lg) var(--gap-lg);
  max-width: var(--content-max-width);
  width: 100%;
}

/* Full-width mode (present builder/live) */
.main-content.full-width .main-inner {
  max-width: none;
  padding: 0;
  height: 100%;
  display: flex;
  flex-direction: column;
}

/* ── Right Sidebar ───────────────────────────────────────── */
.sidebar-right {
  width: var(--sidebar-right-width);
  flex-shrink: 0;
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  background: var(--sidebar-bg);
  border-left: 1px solid var(--sidebar-border);
}

.sidebar-right__inner {
  padding: var(--gap-md) var(--gap-sm);
  display: flex;
  flex-direction: column;
  gap: var(--gap-sm);
  height: 100%;
}

.sidebar-right__title {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  color: var(--text-label);
  padding-bottom: var(--gap-xs);
  border-bottom: 1px solid var(--divider);
}

/* ── IM Panel (slide-in overlay) ─────────────────────────── */
.im-panel {
  position: fixed;
  top: var(--header-height);
  right: 0;
  bottom: 0;
  width: var(--sidebar-right-width);
  z-index: var(--z-im);
  background: var(--sidebar-bg);
  border-left: 1px solid var(--sidebar-border);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  display: flex;
  flex-direction: column;
  transform: translateX(100%);
  transition: transform var(--t-base);
}

.im-panel.open {
  transform: translateX(0);
}

.im-panel__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--gap-md) var(--gap-sm) var(--gap-sm);
  border-bottom: 1px solid var(--divider);
  flex-shrink: 0;
}

.im-panel__title {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  color: var(--text-label);
}

.im-panel__close {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: var(--text-lg);
  line-height: 1;
  padding: 2px 6px;
  border-radius: 4px;
  transition: color var(--t-fast);
}

.im-panel__close:hover { color: var(--text-primary); }

.im-panel__list {
  flex: 1;
  overflow-y: auto;
  padding: var(--gap-sm);
  display: flex;
  flex-direction: column;
  gap: var(--gap-xs);
}

.im-panel__footer {
  padding: var(--gap-sm);
  border-top: 1px solid var(--divider);
  flex-shrink: 0;
}

/* IM Bell button */
.im-bell {
  position: relative;
  background: var(--btn-ghost-bg);
  border: 1px solid var(--btn-ghost-border);
  color: var(--text-secondary);
  border-radius: 8px;
  padding: 5px 10px;
  cursor: pointer;
  font-size: var(--text-lg);
  line-height: 1;
  transition: all var(--t-fast);
}

.im-bell:hover {
  background: var(--btn-ghost-hover-bg);
  color: var(--text-primary);
}

.im-bell__badge {
  position: absolute;
  top: -5px;
  right: -5px;
  min-width: 17px;
  height: 17px;
  border-radius: 9px;
  background: rgba(239,68,68,0.90);
  color: #fff;
  font-size: 10px;
  font-weight: 700;
  line-height: 17px;
  text-align: center;
  padding: 0 3px;
  display: none;
}

/* ── View Root ───────────────────────────────────────────── */
#viewRoot {
  width: 100%;
}

/* ── Present fullscreen mode ─────────────────────────────── */
.app-layout.present-fullscreen .main-content {
  overflow: hidden;
}

.app-layout.present-fullscreen .main-inner {
  max-width: none;
  padding: 0;
  height: 100%;
  overflow: hidden;
}

.app-layout.present-fullscreen #viewRoot {
  height: 100%;
  position: relative;
}

/* ── Page utilities ──────────────────────────────────────── */
.page-centered {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--gap-xl) var(--gap-md);
}

/* ── Scrollbars ──────────────────────────────────────────── */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: var(--scrollbar-track); border-radius: 3px; }
::-webkit-scrollbar-thumb { background: var(--scrollbar-thumb); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { filter: brightness(1.4); }
::-webkit-scrollbar-corner { background: transparent; }
* { scrollbar-width: thin; scrollbar-color: var(--scrollbar-thumb) var(--scrollbar-track); }

/* ── Responsive — tablet ─────────────────────────────────── */
@media (max-width: 900px) {
  :root {
    --sidebar-width: 48px;
    --sidebar-right-width: 0px;
  }

  .sidebar-left__item span:not(.icon) { display: none; }
  .sidebar-left__label { display: none; }
  .sidebar-right { display: none; }
}

/* ── Responsive — mobile (student views) ────────────────── */
@media (max-width: 600px) {
  :root {
    --sidebar-width: 0px;
  }

  .sidebar-left { display: none; }

  .main-inner {
    padding: var(--gap-md);
  }
}