/* Variáveis de design (ver guia de estilo no CLAUDE.md) */
:root {
  --color-bg: #FAFAF8;
  --color-surface: #FFFFFF;
  --color-text: #1F2328;
  --color-text-secondary: #5B6168;
  --color-accent: #2952CC;
  --color-accent-hover: #1F3E9E;
  --color-success: #1F8A5C;
  --color-error: #C0473B;
  --color-border: #E4E5E7;

  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;

  --radius: 8px;
  --font-sans: 'Inter', -apple-system, 'Segoe UI', sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.5;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Foco visível para todo elemento interativo */
a:focus-visible,
button:focus-visible,
input:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.app {
  max-width: 640px;
  margin: 0 auto;
  padding: var(--space-4) var(--space-2) var(--space-6);
}

.app-header {
  text-align: center;
  margin-bottom: var(--space-4);
}

.app-header h1 {
  font-size: 1.75rem;
  font-weight: 700;
  margin: 0 0 var(--space-1);
}

.subtitle {
  color: var(--color-text-secondary);
  margin: 0;
}

/* Área de drop */
.dropzone {
  background-color: var(--color-surface);
  border: 2px dashed var(--color-border);
  border-radius: var(--radius);
  padding: var(--space-4);
  text-align: center;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: border-color 0.15s ease, background-color 0.15s ease;
}

.dropzone:hover {
  border-color: var(--color-accent);
}

.dropzone.drag-over {
  border-color: var(--color-accent);
  background-color: #EEF2FC;
}

.dropzone-icon {
  color: var(--color-accent);
  margin-bottom: var(--space-1);
}

.dropzone-text {
  margin: 0;
}

.dropzone-text strong {
  color: var(--color-text);
}

/* Lista de arquivos */
.file-list-section {
  margin-top: var(--space-3);
}

.merge-summary {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  margin: 0 0 var(--space-1);
  min-height: 1.3em;
}

.file-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.file-item {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--space-1) var(--space-2);
}

.file-item.dragging {
  opacity: 0.5;
}

.file-item--error {
  border-left: 3px solid var(--color-error);
}

.drag-handle {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  cursor: grab;
  color: var(--color-text-secondary);
  font-size: 1.1rem;
  user-select: none;
}

/* Miniatura da primeira página */
.file-thumb-wrap {
  flex-shrink: 0;
  width: 40px;
  height: 52px;
}

.file-thumb {
  width: 40px;
  height: 52px;
  object-fit: contain;
  display: block;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 4px;
}

.file-thumb--loading {
  background-color: var(--color-bg);
  animation: thumb-pulse 1.2s ease-in-out infinite;
}

.file-thumb--error {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--color-error);
  background-color: #FBECEA;
  border-color: var(--color-error);
}

@keyframes thumb-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.file-info {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

.file-name {
  font-weight: 600;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.file-pages {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
}

.file-item--error .file-pages {
  color: var(--color-error);
}

.file-item-actions {
  display: flex;
  gap: var(--space-1);
  flex-shrink: 0;
}

.icon-btn {
  min-width: 44px;
  min-height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text-secondary);
  font-size: 1rem;
  cursor: pointer;
  transition: background-color 0.15s ease, color 0.15s ease;
}

.icon-btn:hover {
  background-color: var(--color-bg);
  color: var(--color-text);
}

.icon-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.remove-btn:hover {
  color: var(--color-error);
  border-color: var(--color-error);
}

/* Status e feedback */
.status {
  margin-top: var(--space-2);
  min-height: 1.3em;
  font-size: 0.95rem;
}

.status[data-state="loading"] {
  color: var(--color-text-secondary);
}

.status[data-state="success"] {
  color: var(--color-success);
  font-weight: 600;
}

.status[data-state="error"] {
  color: var(--color-error);
  font-weight: 600;
}

/* Ações */
.actions {
  margin-top: var(--space-3);
}

.btn-primary {
  width: 100%;
  min-height: 48px;
  background-color: var(--color-accent);
  color: #FFFFFF;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.15s ease;
}

.btn-primary:hover:not(:disabled) {
  background-color: var(--color-accent-hover);
}

.btn-primary:disabled {
  background-color: var(--color-border);
  color: var(--color-text-secondary);
  cursor: not-allowed;
}

/* Download */
.download-area {
  margin-top: var(--space-2);
  padding: var(--space-2);
  background-color: #EAF6EF;
  border: 1px solid var(--color-success);
  border-radius: var(--radius);
}

.success-message {
  margin: 0;
  color: var(--color-success);
  font-weight: 600;
}

.download-link {
  color: var(--color-success);
  text-decoration: underline;
}

.download-link:hover {
  color: #176E49;
}

.app-footer {
  margin-top: var(--space-4);
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 0.85rem;
}

/* Responsividade */
@media (max-width: 480px) {
  .app {
    padding: var(--space-3) var(--space-1) var(--space-4);
  }

  .file-item {
    flex-wrap: wrap;
  }
}