.bottom-tabbar {
  position: fixed;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100%;
  max-width: 100%;
  display: flex;
  justify-content: space-around;
  align-items: flex-start;
  padding: 10px 16px calc(12px + env(safe-area-inset-bottom)) 16px;
  background: rgba(255,255,255,.82);
  backdrop-filter: blur(28px) saturate(220%);
  -webkit-backdrop-filter: blur(28px) saturate(220%);
  border-top: 1px solid rgba(255,255,255,.7);
  box-shadow: 0 -4px 20px rgba(110,140,255,.08);
  z-index: 40;
}

/* 电脑端手机壳内 Tabbar 宽度限制 */
@media (min-width: 1024px) {
  .bottom-tabbar {
    max-width: 390px;
    border-radius: 0 0 36px 36px;
  }
}

.tab-item {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4px 6px;
  position: relative;
  cursor: pointer;
  min-width: 56px;
  -webkit-user-select: none;
  user-select: none;
}

/* 未选中：灰色 */
.tab-item svg.tab-icon {
  width: 24px;
  height: 24px;
  stroke-width: 2;
  fill: none;
  color: #B0B0B0;
  stroke: currentColor;
  transition: color .25s var(--ease), transform .2s var(--ease);
}

.tab-item:active svg.tab-icon {
  transform: scale(0.92);
}

/* Remix Icon 标签图标 */
.tab-item .tab-icon-ri {
  font-size: 24px;
  color: #B0B0B0;
  transition: color .25s var(--ease), transform .2s var(--ease);
}

.tab-item:active .tab-icon-ri {
  transform: scale(0.92);
}

.tab-item.active .tab-icon-ri {
  color: var(--primary);
}

.tab-item span.tab-label {
  margin-top: 4px;
  font-size: 11px;
  color: #B0B0B0;
  transition: color .25s var(--ease);
  font-weight: 500;
}

/* 选中：亮色 */
.tab-item.active svg.tab-icon {
  color: var(--primary);
  stroke-width: 2.2;
}

.tab-item.active span.tab-label {
  color: var(--primary);
  font-weight: 600;
}

/* 选中状态：仅颜色变化，无顶部短线 */

.tab-center-ai {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  margin-top: -28px;
  padding: 2px;
  background: linear-gradient(135deg, var(--tab-chat) 0%, var(--tab-chat-2) 50%, var(--tab-chat-3) 100%);
  box-shadow: var(--shadow-primary);
  border: 2px solid #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: transform .18s var(--ease);
}

.tab-center-ai:active {
  transform: scale(0.94);
}

.tab-center-ai img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 50%;
  background: white;
}

.tab-item[data-tab="center"].active .tab-center-ai {
  animation: pulse-glow 1.6s infinite ease-in-out;
}

/* ===== AI 聊天图标圆圈扩散动画 - 白色版本 ===== */
.tab-center-ai {
  position: relative;
  isolation: isolate;
}

.tab-center-ai::before,
.tab-center-ai::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 50%;
  border: 2px solid rgba(255,255,255,.6);
  pointer-events: none;
  z-index: -1;
  animation: aiRipple 2.4s ease-out infinite;
}

.tab-center-ai::before {
  animation-delay: 0s;
}

.tab-center-ai::after {
  animation-delay: 1.2s;
}

@keyframes aiRipple {
  0% {
    transform: scale(1);
    opacity: .7;
    border-color: rgba(255,255,255,.6);
  }
  100% {
    transform: scale(1.7);
    opacity: 0;
    border-color: rgba(255,255,255,.05);
  }
}