/* ── 右下角悬浮按钮 ── */
.accessibility-fab {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--color-bg-primary);
  border: 1px solid var(--color-border-primary);
  color: var(--color-text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 9998;
  transition: color 0.2s, border-color 0.2s, box-shadow 0.2s, transform 0.2s;
  text-decoration: none;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.accessibility-fab:hover {
  color: var(--color-text-primary);
  border-color: var(--color-accent-emphasis, #0969da);
  box-shadow: 0 4px 16px rgba(9,105,218,0.15);
  transform: scale(1.08);
}

/* ── 面板弹出动画 ── */
@keyframes panel-in {
  from {
    opacity: 0;
    transform: translateY(12px) scale(0.97);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@keyframes panel-out {
  from {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
  to {
    opacity: 0;
    transform: translateY(12px) scale(0.97);
  }
}

/* ── 面板 ── */
.accessibility-menu {
  position: fixed;
  bottom: 76px;
  right: 24px;
  top: auto;
  background: var(--color-bg-primary);
  border: 1px solid var(--color-border-primary);
  border-radius: 12px;
  width: 300px;
  max-height: 80vh;
  overflow-y: auto;
  z-index: 9999;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  box-shadow: 0 8px 32px rgba(0,0,0,0.12), 0 2px 8px rgba(0,0,0,0.06);
  transform-origin: bottom right;
  animation: panel-in 0.22s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

.accessibility-menu.hiding {
  animation: panel-out 0.18s ease-in both;
}

/* 滚动条美化 */
.accessibility-menu::-webkit-scrollbar {
  width: 4px;
}
.accessibility-menu::-webkit-scrollbar-track {
  background: transparent;
}
.accessibility-menu::-webkit-scrollbar-thumb {
  background: var(--color-border-primary);
  border-radius: 2px;
}

/* ── 面板头部 ── */
.accessibility-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 16px;
  border-bottom: 1px solid var(--color-border-primary);
  background: var(--color-bg-secondary);
  border-radius: 12px 12px 0 0;
  position: sticky;
  top: 0;
  z-index: 1;
}

.accessibility-header h3 {
  margin: 0;
  font-size: 14px;
  font-weight: 600;
  color: var(--color-text-primary);
  letter-spacing: 0.01em;
}

.close-btn {
  background: transparent;
  border: none;
  font-size: 18px;
  cursor: pointer;
  color: var(--color-text-secondary);
  padding: 0;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 4px;
  transition: color 0.15s, background 0.15s;
  outline: none;
}

.close-btn:hover {
  color: var(--color-text-primary);
  background: var(--color-border-primary);
}

/* ── 选项区 ── */
.accessibility-options {
  padding: 12px 16px 16px;
}

.option-group {
  margin-bottom: 18px;
}

.option-group:last-child {
  margin-bottom: 0;
}

.option-group h4 {
  margin: 0 0 8px 0;
  font-size: 11px;
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.option-item {
  display: flex;
  align-items: flex-start;
  padding: 8px 0;
  cursor: pointer;
  border-bottom: 1px solid var(--color-border-secondary, rgba(0,0,0,0.06));
}

.option-item:last-child {
  border-bottom: none;
}

/* ── Checkbox 美化 ── */
.option-item input[type="checkbox"] {
  width: 16px;
  height: 16px;
  margin: 1px 10px 0 0;
  accent-color: var(--color-accent-emphasis, #0969da);
  flex-shrink: 0;
  cursor: pointer;
}

.checkmark { display: none; }

.option-content { flex: 1; }

.option-content strong {
  display: block;
  font-size: 13px;
  font-weight: 500;
  color: var(--color-text-primary);
  margin-bottom: 1px;
}

.option-content small {
  font-size: 11px;
  color: var(--color-text-secondary);
  line-height: 1.4;
}

/* ── 滑块行 ── */
.slider-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 6px;
}

.slider-label {
  font-size: 12px;
  color: var(--color-text-secondary);
}

.slider-value {
  font-size: 11px;
  font-weight: 600;
  color: var(--color-accent-emphasis, #0969da);
  background: var(--color-accent-subtle, #ddf4ff);
  padding: 1px 6px;
  border-radius: 10px;
  min-width: 36px;
  text-align: center;
}

.option-item input[type="range"] {
  width: 100%;
  margin: 2px 0 0;
  -webkit-appearance: none;
  appearance: none;
  height: 4px;
  border-radius: 2px;
  background: var(--color-border-primary);
  outline: none;
  cursor: pointer;
  transition: background 0.15s;
}

.option-item input[type="range"]:hover {
  background: var(--color-border-muted, #d0d7de);
}

/* track 填充色（webkit only，用 JS 辅助） */
.option-item input[type="range"].filled {
  background: linear-gradient(
    to right,
    var(--color-accent-emphasis, #0969da) 0%,
    var(--color-accent-emphasis, #0969da) var(--fill, 0%),
    var(--color-border-primary) var(--fill, 0%),
    var(--color-border-primary) 100%
  );
}

.option-item input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--color-accent-emphasis, #0969da);
  cursor: pointer;
  border: 2.5px solid var(--color-bg-primary);
  box-shadow: 0 1px 4px rgba(9,105,218,0.3);
  transition: transform 0.12s, box-shadow 0.12s;
}

.option-item input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
  box-shadow: 0 2px 8px rgba(9,105,218,0.4);
}

.option-item input[type="range"]::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-accent-emphasis, #0969da);
  cursor: pointer;
  border: 2px solid var(--color-bg-primary);
  box-shadow: 0 1px 4px rgba(9,105,218,0.3);
}

.option-item input[type="range"]::-moz-range-progress {
  background: var(--color-accent-emphasis, #0969da);
  height: 4px;
  border-radius: 2px;
}

/* ── 字体切换按钮 ── */
.font-toggle-wrap {
  display: flex;
  gap: 6px;
}

.font-toggle-btn {
  flex: 1;
  padding: 7px 0;
  border: 1px solid var(--color-border-primary);
  border-radius: 8px;
  background: transparent;
  color: var(--color-text-secondary);
  cursor: pointer;
  font-size: 12px;
  transition: background 0.12s, border-color 0.12s, color 0.12s, transform 0.1s;
  text-align: center;
  outline: none;
}

.font-toggle-btn:hover {
  background: var(--color-bg-secondary);
  color: var(--color-text-primary);
  transform: translateY(-1px);
}

.font-toggle-btn.active {
  border-color: var(--color-accent-emphasis, #0969da);
  color: var(--color-accent-emphasis, #0969da);
  background: var(--color-accent-subtle, #ddf4ff);
  font-weight: 600;
}

/* ── 恢复默认 ── */
.reset-btn {
  width: 100%;
  padding: 9px;
  background: transparent;
  border: 1px solid var(--color-border-primary);
  border-radius: 8px;
  color: var(--color-text-secondary);
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
  outline: none;
  letter-spacing: 0.02em;
}

.reset-btn:hover {
  background: var(--color-bg-secondary);
  color: var(--color-text-primary);
  border-color: var(--color-text-secondary);
}

/* ── 阅读进度条 ── */
.reading-progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: transparent;
  z-index: 9999;
}

.progress-fill {
  height: 100%;
  background: var(--color-accent-emphasis, #0969da);
  width: 0%;
  transition: width 0.15s ease;
  border-radius: 0 2px 2px 0;
}

/* ── 棕色滤镜 ── */
.brown-filter-overlay {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  pointer-events: none;
  z-index: 998;
  background: rgba(139, 69, 19, 0);
  transition: background 0.3s ease;
  mix-blend-mode: multiply;
}

/* ── CSS 变量 ── */
:root {
  --custom-font-size: 16px;
  --custom-line-height: 1.6;
  --custom-letter-spacing: 0px;
  --custom-font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

.markdown-body, .post, article, .post-content {
  font-size: var(--custom-font-size) !important;
  line-height: var(--custom-line-height) !important;
  letter-spacing: var(--custom-letter-spacing) !important;
  font-family: var(--custom-font-family) !important;
}

/* ── 响应式 ── */
@media (max-width: 768px) {
  .accessibility-fab {
    bottom: 16px;
    right: 16px;
  }
  .accessibility-menu {
    bottom: 68px;
    right: 16px;
    width: calc(100vw - 32px);
  }
}