/* FitCoach AI - 统一底部导航样式 */

.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 390px;
  background: rgba(252, 253, 255, 0.88);
  backdrop-filter: blur(28px) saturate(160%);
  -webkit-backdrop-filter: blur(28px) saturate(160%);
  border-top: 1px solid rgba(15, 23, 42, 0.06);
  padding: 10px 18px 30px;
  display: flex;
  justify-content: space-around;
  align-items: flex-end;
  z-index: 1000;
  -webkit-tap-highlight-color: transparent;
  box-shadow: 0 -10px 30px rgba(15, 23, 42, 0.06);
}

.nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  color: #98A2B3;
  cursor: pointer;
  transition: all 0.22s ease;
  min-width: 60px;
  user-select: none;
}

.nav-item:active {
  opacity: 0.75;
  transform: scale(0.96);
  transition: all 0.1s ease;
}

.nav-item.active {
  color: #111827;
}

.nav-icon {
  width: 24px;
  height: 24px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 1;
  flex-shrink: 0;
}

.nav-icon svg {
  width: 22px;
  height: 22px;
  display: block;
  overflow: visible;
  stroke: currentColor;
  fill: none;
}

.nav-label {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.2px;
}

.ai-btn {
  width: 54px;
  height: 54px;
  background: linear-gradient(135deg, #151B2C 0%, #2B3448 100%);
  border: 4px solid rgba(255,255,255,0.95);
  border-radius: 50%;
  color: white;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 10px 22px rgba(17, 24, 39, 0.22);
  margin-bottom: 2px;
  transition: all 0.22s ease;
  padding: 0;
  outline: none;
  -webkit-tap-highlight-color: transparent;
}

.ai-btn-icon {
  width: 24px;
  height: 24px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.ai-btn-icon svg {
  width: 22px;
  height: 22px;
  display: block;
  overflow: visible;
  stroke: currentColor;
  fill: none;
}

.ai-btn:active {
  transform: scale(0.93);
  box-shadow: 0 6px 14px rgba(17, 24, 39, 0.22);
}

@media (max-width: 375px) {
  .bottom-nav {
    width: 100%;
    padding: 10px 14px 28px;
  }

  .nav-item {
    min-width: 50px;
    gap: 4px;
  }

  .nav-icon {
    width: 22px;
    height: 22px;
  }

  .nav-icon svg {
    width: 20px;
    height: 20px;
  }

  .nav-label {
    font-size: 9px;
  }

  .ai-btn {
    width: 50px;
    height: 50px;
  }
}

@supports (padding-bottom: env(safe-area-inset-bottom)) {
  .bottom-nav {
    padding-bottom: calc(30px + env(safe-area-inset-bottom));
  }
}