/* ==========================================================================
   右侧固定工具条
   参考什么值得买：贴边、纯图标、无圆角无阴影，视觉重量接近于零。
   ========================================================================== */

.side-rail {
  position: fixed;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  z-index: 900;
  display: flex;
  flex-direction: column;
}

.side-rail-item {
  position: relative;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #FFFFFF;
  border: 1px solid var(--border-light);
  border-bottom: none;
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition-fast);
  /* 按钮与链接混用，统一掉浏览器默认样式 */
  padding: 0;
  margin: 0;
  font: inherit;
  text-decoration: none;
  appearance: none;
}

.side-rail-item:last-child {
  border-bottom: 1px solid var(--border-light);
}

.side-rail-item:hover,
.side-rail-item:focus-visible {
  background: var(--gold-light);
  color: var(--gold-dark);
  outline: none;
}

/* 首位是主转化入口，给一点金色暗示，但不做成大色块 */
.side-rail-primary {
  color: var(--gold-dark);
}

.side-rail-primary::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--gold-primary);
}

.side-rail-icon {
  display: flex;
  align-items: center;
  justify-content: center;
}

/* -------------------------------------------------------------------------
   悬停面板
   ---------------------------------------------------------------------- */

.side-rail-panel {
  position: absolute;
  right: 52px;
  top: 50%;
  transform: translateY(-50%) translateX(6px);
  min-width: 108px;
  background: #FFFFFF;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-soft);
  padding: 10px 14px;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: var(--transition-fast);
  white-space: nowrap;
}

.side-rail-panel-wide {
  min-width: 168px;
}

.side-rail-item:hover .side-rail-panel,
.side-rail-item:focus-within .side-rail-panel {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateY(-50%) translateX(0);
}

.side-rail-panel-title {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-main);
}

.side-rail-panel-text {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.side-rail-links {
  list-style: none;
  margin: 8px 0 0;
  padding: 0;
}

.side-rail-links li + li {
  margin-top: 2px;
}

.side-rail-links a {
  display: block;
  padding: 5px 8px;
  margin: 0 -8px;
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  color: var(--text-body);
  text-decoration: none;
  transition: var(--transition-fast);
}

.side-rail-links a:hover {
  background: var(--gold-light);
  color: var(--gold-dark);
}

/* 返回顶部：滚动一段距离后才出现 */
.side-rail-top {
  display: none;
}

.side-rail-top.is-visible {
  display: flex;
}

/* -------------------------------------------------------------------------
   移动端
   窄屏没有空间放侧边条，隐藏；底部已有移动操作栏承担同样功能。
   ---------------------------------------------------------------------- */

@media (max-width: 900px) {
  .side-rail {
    display: none;
  }
}