/* App shell: fixed header + footer, content scrolls between */
body {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

main {
  flex: 1 1 auto;
  overflow-y: auto;
  min-height: 0;
}

/* Header */
.header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  height: var(--header-height);
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-6);
}

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

.header__logo {
  width: 32px;
  height: 32px;
  object-fit: contain;
}

.header__title {
  font-size: var(--text-lg);
  font-weight: var(--weight-semibold);
  color: var(--color-text);
}

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

/* App layout — single column, fills main */
.app-layout {
  display: flex;
  flex-direction: column;
  min-height: 100%;
}

/* Workspace (full width, fills main) */
.workspace {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: var(--space-6);
  min-width: 0;
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
}

/* Empty state — hero drop zone, centered in available space */
.workspace__empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  margin-top: auto;
  margin-bottom: auto;
  color: var(--color-text-tertiary);
  text-align: center;
  gap: var(--space-4);
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  transition: all var(--transition-fast);
}

.workspace__empty:hover,
.workspace__empty.is-dragover {
  border-color: var(--color-primary);
  background-color: var(--color-drop-zone);
}

.workspace__empty.is-dragover .workspace__empty-icon {
  transform: translateY(-4px);
}

.workspace__empty-icon {
  width: 64px;
  height: 64px;
  opacity: 0.4;
  color: var(--color-primary);
  transition: transform var(--transition-fast);
}

.workspace__empty-text {
  font-size: var(--text-lg);
  font-weight: var(--weight-medium);
  color: var(--color-text);
}

.workspace__empty-cta {
  margin-top: var(--space-2);
}

.workspace__empty-formats {
  font-size: var(--text-xs);
  color: var(--color-text-tertiary);
}

/* Image grid */
.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-6);
}

/* Workspace drag-over state (when grid is visible) */
.workspace.is-dragover {
  outline: 2px dashed var(--color-primary);
  outline-offset: -2px;
  background-color: var(--color-drop-zone);
  border-radius: var(--radius-lg);
}

/* Workspace drag rejection */
.workspace.is-dragover-reject .workspace__empty {
  border-color: var(--color-error);
  background-color: var(--color-error-subtle);
}

.workspace.is-dragover-reject .workspace__empty-icon {
  color: var(--color-error);
}

/* Mobile */
@media (max-width: 640px) {
  .header {
    padding: 0 var(--space-4);
  }

  .workspace {
    padding: var(--space-4);
    padding-bottom: calc(var(--space-20) + env(safe-area-inset-bottom, 0px));
  }

  .image-grid {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }
}