/* ==========================================================================
   APP SHELL LAYOUT — sidebar + topnav + workspace grid
   ========================================================================== */

.app-shell {
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr;
  grid-template-rows: var(--topnav-height) 1fr;
  grid-template-areas:
    "sidebar topnav"
    "sidebar main";
  min-height: 100vh;
  transition: grid-template-columns var(--duration-base) var(--ease-standard);
}

.app-shell.is-collapsed {
  grid-template-columns: var(--sidebar-width-collapsed) 1fr;
}

/* ---------------- Sidebar ---------------- */
.sidebar {
  grid-area: sidebar;
  background: var(--color-bg-surface);
  border-right: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  position: sticky;
  top: 0;
  height: 100vh;
  z-index: var(--z-sidebar);
  overflow: hidden;
}

.sidebar__brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: 0 var(--space-5);
  height: var(--topnav-height);
  border-bottom: 1px solid var(--color-border);
  flex-shrink: 0;
}

.sidebar__brand-mark {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
  border-radius: var(--radius-md);
  background: var(--color-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
}

.sidebar__brand-name {
  font-weight: var(--fw-semibold);
  font-size: var(--fs-md);
  letter-spacing: -0.01em;
  white-space: nowrap;
  overflow: hidden;
}

.sidebar__nav {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-4) var(--space-3);
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.sidebar__section-label {
  padding: var(--space-4) var(--space-3) var(--space-2);
  font-size: var(--fs-xs);
  font-weight: var(--fw-semibold);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-tertiary);
  white-space: nowrap;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-3);
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  font-weight: var(--fw-medium);
  font-size: var(--fs-sm);
  white-space: nowrap;
  transition: background var(--duration-fast) var(--ease-standard), color var(--duration-fast) var(--ease-standard);
  position: relative;
}

.nav-item svg {
  width: 18px;
  height: 18px;
  color: currentColor;
}

.nav-item:hover {
  background: var(--color-bg-hover);
  color: var(--color-text-primary);
}

.nav-item.is-active {
  background: var(--color-accent-soft);
  color: var(--color-accent);
}

.nav-item.is-active svg {
  color: var(--color-accent);
}

.sidebar__footer {
  padding: var(--space-3);
  border-top: 1px solid var(--color-border);
  flex-shrink: 0;
}

.sidebar-collapse-btn {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-2) var(--space-3);
  border: none;
  background: transparent;
  border-radius: var(--radius-md);
  color: var(--color-text-tertiary);
  font-size: var(--fs-xs);
}
.sidebar-collapse-btn:hover {
  background: var(--color-bg-hover);
  color: var(--color-text-secondary);
}

.app-shell.is-collapsed .sidebar__brand-name,
.app-shell.is-collapsed .sidebar__section-label,
.app-shell.is-collapsed .nav-item span,
.app-shell.is-collapsed .sidebar-collapse-btn span {
  display: none;
}
.app-shell.is-collapsed .nav-item {
  justify-content: center;
}

/* ---------------- Top nav ---------------- */
.topnav {
  grid-area: topnav;
  height: var(--topnav-height);
  background: var(--color-bg-surface);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-6);
  gap: var(--space-4);
  position: sticky;
  top: 0;
  z-index: var(--z-topnav);
}

.topnav__left {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex: 1;
  min-width: 0;
}

.topnav__search {
  max-width: 360px;
  width: 100%;
}

.topnav__right {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

.icon-btn {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  background: transparent;
  color: var(--color-text-secondary);
  position: relative;
  transition: background var(--duration-fast) var(--ease-standard), color var(--duration-fast) var(--ease-standard);
}
.icon-btn:hover {
  background: var(--color-bg-hover);
  color: var(--color-text-primary);
}
.icon-btn svg { width: 18px; height: 18px; }

.icon-btn__badge {
  position: absolute;
  top: 4px;
  right: 4px;
  width: 8px;
  height: 8px;
  border-radius: var(--radius-full);
  background: var(--color-danger);
  border: 2px solid var(--color-bg-surface);
}

.topnav__customer-chip {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  background: var(--color-bg-sunken);
  font-size: var(--fs-sm);
  font-weight: var(--fw-medium);
  color: var(--color-text-secondary);
  white-space: nowrap;
}

.user-profile-btn {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-2) var(--space-1) var(--space-1);
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: var(--color-bg-surface);
}
.user-profile-btn:hover { background: var(--color-bg-hover); }

.avatar {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-full);
  background: var(--color-accent);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--fs-xs);
  font-weight: var(--fw-semibold);
  flex-shrink: 0;
}

/* ---------------- Main workspace ---------------- */
.main {
  grid-area: main;
  padding: var(--space-7);
  max-width: 1400px;
  width: 100%;
  margin: 0 auto;
}

.page-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-4);
  margin-bottom: var(--space-7);
  flex-wrap: wrap;
}

.page-header__title {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.page-header__actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.page-subtitle {
  color: var(--color-text-secondary);
  font-size: var(--fs-base);
}

/* Grid helpers */
.grid {
  display: grid;
  gap: var(--space-5);
}
.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

.section-stack {
  display: flex;
  flex-direction: column;
  gap: var(--space-7);
}

/* ---------------- Mobile sidebar ---------------- */
.sidebar-scrim {
  display: none;
}

@media (max-width: 1080px) {
  .grid-cols-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-cols-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 860px) {
  .app-shell {
    grid-template-columns: 1fr;
    grid-template-areas:
      "topnav"
      "main";
  }
  .sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: var(--sidebar-width);
    transform: translateX(-100%);
    transition: transform var(--duration-base) var(--ease-standard);
    box-shadow: var(--shadow-xl);
  }
  .app-shell.is-mobile-open .sidebar {
    transform: translateX(0);
  }
  .app-shell.is-mobile-open .sidebar-scrim {
    display: block;
    position: fixed;
    inset: 0;
    background: var(--color-bg-overlay);
    z-index: 90;
  }
  .main { padding: var(--space-5); }
  .grid-cols-2, .grid-cols-3, .grid-cols-4 { grid-template-columns: 1fr; }
  .topnav__search { display: none; }
}