/* ==========================================================================
   AI Photo Studio - A11y (Accessibility) Styles
   Focus rings, micro-interactions, ARIA-supporting styles
   ========================================================================== */

/* ===== Focus 视觉 ===== */

:root {
  --focus-ring-color: var(--brand-accent);
  --focus-ring-width: 2px;
  --focus-ring-offset: 2px;
  --focus-ring-style: solid;
}

/* 键盘用户的清晰 focus 轮廓 */
*:focus-visible {
  outline: var(--focus-ring-width) var(--focus-ring-style) var(--focus-ring-color);
  outline-offset: var(--focus-ring-offset);
  border-radius: var(--radius-sm);
}

/* 隐藏鼠标用户的 focus 轮廓（保留键盘用户） */
*:focus:not(:focus-visible) {
  outline: none;
}

/* ===== 微交互 Transition ===== */

button,
.gallery-thumb,
.preset-card,
.thumb-bg,
.btn,
.btn-culling-start,
.project-card,
.compareBtn,
.filter-panel-enhance button {
  transition:
    background-color var(--transition-normal),
    border-color var(--transition-normal),
    color var(--transition-normal),
    transform var(--transition-fast),
    box-shadow var(--transition-normal);
}

button:hover:not(:disabled),
.btn:hover:not(:disabled) {
  transform: translateY(-1px);
}

button:active:not(:disabled),
.btn:active:not(:disabled) {
  transform: translateY(0);
}

/* ===== Modal Focus Trap (辅助样式) ===== */

.modal-visible {
  /* 由 JS 控制 focus trap；CSS 仅负责遮罩与可见性 */
}

.modal[aria-modal="true"] {
  position: fixed;
  inset: 0;
  z-index: var(--z-overlay);
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
}

/* ===== Lightbox ARIA ===== */

.lightbox[role="dialog"][aria-modal="true"] {
  /* 由 JS 控制；CSS 仅保留显示逻辑 */
}

/* ===== 进度条 ARIA ===== */

.progress-bar[role="progressbar"] {
  position: relative;
  background: var(--bg-tertiary);
  border-radius: var(--radius-sm);
  overflow: hidden;
  height: 6px;
}

.progress-bar-fill {
  height: 100%;
  background: var(--brand-accent);
  transition: width var(--transition-slow);
}

/* ===== Toast ARIA ===== */

.toast-notification[role="alert"] {
  /* 由 showToast() 注入；CSS 兼容 */
}

/* ===== 缩略图 ARIA ===== */

.gallery-thumb[role="button"] {
  cursor: pointer;
}

.gallery-thumb[aria-selected="true"] {
  /* 选中态视觉（与现有 .selected 类共存） */
  border-color: var(--brand-accent);
  box-shadow: 0 0 0 2px var(--brand-accent);
}

/* ===== 错误状态 ===== */

.error-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 24px;
  text-align: center;
  color: var(--text-tertiary);
  background: var(--bg-secondary);
  border: 1px dashed var(--border-default);
  border-radius: var(--radius-md);
}

.error-state-icon {
  font-size: 32px;
  margin-bottom: 8px;
  opacity: 0.6;
}

.error-state-message {
  font-size: 13px;
  color: var(--text-secondary);
}

.error-state-action {
  margin-top: 12px;
  padding: 6px 12px;
  background: var(--brand-accent);
  color: var(--brand-dark);
  border: none;
  border-radius: var(--radius-sm);
  font-size: 12px;
  cursor: pointer;
}

/* ===== Skip Link（高级 A11y，可选启用） ===== */

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: var(--z-skip);
  padding: 8px 16px;
  background: var(--brand-accent);
  color: var(--brand-dark);
  text-decoration: none;
  border-radius: 0 0 var(--radius-sm) 0;
}

.skip-link:focus {
  left: 0;
}

/* ===== EOF ===== */