/* ===========================================
   Layout — Sidebar Shell & App Structure
   =========================================== */

.app-shell {
  display: flex;
  height: 100vh;
  overflow: hidden;
  background: var(--bg-app);
}

/* ── Sidebar ── */
.app-sidebar {
  width: var(--sidebar-width);
  flex-shrink: 0;
  height: 100vh;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--sidebar-border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  z-index: var(--z-topbar);
  transition: transform var(--transition-base);
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-5);
  border-bottom: 1px solid var(--sidebar-border);
  flex-shrink: 0;
  text-decoration: none;
}
.sidebar-logo-mark {
  width: 32px; height: 32px;
  background: var(--color-primary-600);
  border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-weight: var(--weight-bold); font-size: var(--text-sm);
  flex-shrink: 0;
}
.sidebar-brand-name {
  font-size: var(--text-base); font-weight: var(--weight-bold);
  color: var(--text-primary); letter-spacing: -0.02em; line-height: 1;
}
.sidebar-brand-sub {
  display: block; font-size: 0.625rem; font-weight: var(--weight-medium);
  color: var(--text-tertiary); text-transform: uppercase;
  letter-spacing: 0.06em; margin-top: 2px;
}

.sidebar-nav {
  flex: 1; padding: var(--space-3);
  overflow-y: auto; display: flex; flex-direction: column; gap: 2px;
}
.sidebar-nav-label {
  display: block; font-size: var(--text-xs); font-weight: var(--weight-semibold);
  color: var(--text-tertiary); text-transform: uppercase; letter-spacing: 0.07em;
  padding: 0 var(--space-2); margin: var(--space-3) 0 var(--space-2);
}
.sidebar-nav-item {
  display: flex; align-items: center; gap: var(--space-3);
  padding: 7px var(--space-3); border-radius: var(--radius-md);
  font-size: var(--text-sm); font-weight: var(--weight-medium);
  color: var(--text-secondary); cursor: pointer;
  transition: all var(--transition-fast);
  border: 1px solid transparent; text-decoration: none; user-select: none;
}
.sidebar-nav-item i { width: 15px; text-align: center; font-size: 0.8rem; flex-shrink: 0; }
.sidebar-nav-item:hover { background: var(--bg-surface-hover); color: var(--text-primary); }
.sidebar-nav-item.active {
  background: rgba(59, 130, 246, 0.1);
  color: var(--color-primary-400);
  border-color: rgba(59, 130, 246, 0.15);
}
[data-theme="light"] .sidebar-nav-item.active {
  background: rgba(37, 99, 235, 0.07);
  color: var(--color-primary-600);
  border-color: rgba(37, 99, 235, 0.1);
}

.sidebar-footer {
  padding: var(--space-3); border-top: 1px solid var(--sidebar-border); flex-shrink: 0;
}
.sidebar-theme-toggle {
  display: flex; align-items: center; gap: var(--space-3); width: 100%;
  padding: 7px var(--space-3); border-radius: var(--radius-md);
  font-size: var(--text-sm); font-weight: var(--weight-medium);
  color: var(--text-secondary); background: transparent;
  border: 1px solid transparent; cursor: pointer;
  transition: all var(--transition-fast); text-align: left; font-family: var(--font-family);
}
.sidebar-theme-toggle i { width: 15px; text-align: center; flex-shrink: 0; font-size: 0.8rem; }
.sidebar-theme-toggle:hover { background: var(--bg-surface-hover); color: var(--text-primary); }

/* ── Main Area ── */
.main-area {
  flex: 1; display: flex; flex-direction: column;
  overflow: hidden; min-width: 0; background: var(--bg-app);
}

.mobile-topbar {
  display: none; align-items: center; justify-content: space-between;
  padding: 0 var(--space-4); height: var(--topbar-h);
  background: var(--topbar-bg); border-bottom: 1px solid var(--topbar-border);
  flex-shrink: 0; backdrop-filter: blur(10px);
}
.mobile-brand { font-size: var(--text-base); font-weight: var(--weight-bold); color: var(--text-primary); }
.mobile-menu-btn, .mobile-theme-btn {
  width: 34px; height: 34px; display: flex; align-items: center; justify-content: center;
  border-radius: var(--radius-md); background: transparent;
  border: 1px solid var(--border-default); color: var(--text-secondary); cursor: pointer; font-size: 0.85rem;
  transition: all var(--transition-fast);
}
.mobile-menu-btn:hover, .mobile-theme-btn:hover { background: var(--bg-surface-hover); color: var(--text-primary); }

#main-content {
  flex: 1; overflow: hidden; display: flex; flex-direction: column; min-height: 0;
}
.page-scroll { flex: 1; overflow-y: auto; overflow-x: hidden; }
.page-container {
  max-width: 1080px; margin: 0 auto;
  padding: var(--space-8) var(--space-8);
  animation: fadeIn var(--transition-base) ease-out both;
}

.section { margin-bottom: var(--space-10); }
.section-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: var(--space-4);
}
.section-title {
  font-size: var(--text-sm); font-weight: var(--weight-semibold);
  color: var(--text-secondary); text-transform: uppercase;
  letter-spacing: 0.05em;
}
.card-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); gap: var(--space-3);
}

/* ── Editor Layout ── */
.editor-layout {
  display: flex; flex: 1; overflow: hidden; background: var(--bg-app);
}
.editor-sidebar {
  width: 400px; min-width: 300px; max-width: 460px;
  background: var(--bg-surface-solid); border-right: 1px solid var(--border-default);
  display: flex; flex-direction: column; overflow: hidden; z-index: 10;
}
.editor-sidebar-header {
  padding: var(--space-4) var(--space-5); border-bottom: 1px solid var(--border-default);
  background: var(--bg-surface-solid); display: flex; flex-direction: column; gap: var(--space-3);
}
.editor-sidebar-top { display: flex; align-items: center; justify-content: space-between; }
.editor-back-btn {
  display: inline-flex; align-items: center; gap: var(--space-2);
  font-size: var(--text-xs); font-weight: var(--weight-semibold);
  color: var(--text-secondary); cursor: pointer;
  background: var(--bg-surface-raised); border: 1px solid var(--border-default);
  padding: 5px var(--space-3); border-radius: var(--radius-md);
  transition: all var(--transition-fast); font-family: var(--font-family);
}
.editor-back-btn:hover { color: var(--color-primary-400); border-color: var(--color-primary-500); background: rgba(59,130,246,0.06); }
[data-theme="light"] .editor-back-btn:hover { color: var(--color-primary-600); background: var(--color-primary-50); }
.editor-doc-title { font-size: var(--text-md); font-weight: var(--weight-bold); color: var(--text-primary); letter-spacing: -0.02em; }
.editor-sidebar-body {
  flex: 1; overflow-y: auto; padding: var(--space-4) var(--space-5);
  display: flex; flex-direction: column; gap: var(--space-4);
}
.editor-sidebar-footer {
  padding: var(--space-4) var(--space-5); border-top: 1px solid var(--border-default);
  background: var(--bg-surface-solid); display: flex; flex-direction: column; gap: var(--space-2);
}
.editor-preview {
  flex: 1; overflow-y: auto; padding: var(--space-8);
  display: flex; justify-content: center; align-items: flex-start;
  background: var(--bg-preview);
  background-image: radial-gradient(var(--border-strong) 1px, transparent 1px);
  background-size: 22px 22px;
}

/* A4 Paper */
.a4-paper {
  width: 210mm; min-height: 297mm; background: white; padding: 2.5cm 2cm;
  box-shadow: 0 8px 40px rgba(0,0,0,0.4);
  color: #000; font-family: 'Calibri', 'Open Sans', sans-serif;
  font-size: 11pt; line-height: 1.5; box-sizing: border-box; flex-shrink: 0;
}
.a4-paper p { color: #000; }

/* Sidebar overlay for mobile */
.sidebar-overlay {
  display: none; position: fixed; inset: 0;
  background: var(--bg-overlay); z-index: calc(var(--z-topbar) - 1);
}
.sidebar-overlay.visible { display: block; }

/* ── Responsive ── */
@media (max-width: 900px) {
  .app-sidebar {
    position: fixed; top: 0; left: 0; bottom: 0;
    transform: translateX(-100%); z-index: var(--z-topbar);
  }
  .app-sidebar.open { transform: translateX(0); }
  .mobile-topbar { display: flex; }
  .editor-layout { flex-direction: column; }
  .editor-sidebar { width: 100%; max-width: 100%; border-right: none; border-bottom: 1px solid var(--border-default); max-height: 50vh; }
  .editor-preview { padding: var(--space-4); min-height: 50vh; }
  .a4-paper { width: 100%; min-height: auto; padding: 1.5cm 1cm; }
}
@media (max-width: 600px) {
  .page-container { padding: var(--space-5) var(--space-4); }
  .card-grid { grid-template-columns: 1fr; }
}