/* ===== 通用变量 ===== */
:root {
  --jade-gold: #b98d54;      /* 玉石金棕 */
  --jade-gray: #555;         /* 主文字 */
  --jade-light: rgba(255, 255, 255, 0.85);
  --jade-border: rgba(0, 0, 0, 0.05);
}



/* ===== 导航栏基底 ===== */
.index-navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  box-sizing: border-box;
  background: var(--jade-light);
  backdrop-filter: blur(12px);
  transition: top 0.3s ease-in-out;
  z-index: 1000;
  padding: 12px 5%;          /* 默认用百分比，避免大屏空白 */
  border-bottom: 1px solid var(--jade-border);
}

.index-navbar.hidden {
  top: -100px;
}

.index-nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1400px;
  margin: 0 auto;
}

.index-logo {
  font-size: 22px;
  font-weight: 500;
  color: #3a3a3a;
  display: flex;
  align-items: center;
  height: 40px;
  letter-spacing: 1px;
}

.index-logo img {
  max-height: 100%;
  width: auto;
  object-fit: contain;
  user-select: none;
}

.index-nav-menu {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 36px;
  margin: 0;
  padding: 0;
}

.index-nav-menu a {
  color: var(--jade-gray);
  text-decoration: none;
  font-weight: 400;
  padding-bottom: 6px;
  position: relative;
  transition: color 0.3s ease;
  font-size: 16px;
  letter-spacing: 0.5px;
}

.index-nav-menu a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  height: 2px;
  width: 0;
  background: var(--jade-gold);
  transition: width 0.3s ease;
}

.index-nav-menu a:hover::after,
.index-nav-menu a.active::after {
  width: 100%;
}

.index-nav-menu a:hover,
.index-nav-menu a.active {
  color: var(--jade-gold);
}

/* ===== iPad 竖屏及以下（≤1024px） ===== */
@media (max-width: 1024px) {
  .index-navbar {
    padding: 12px 3%;
  }
  .index-nav-menu {
    gap: 24px;
  }
}

/* ===== 手机（≤767px） ===== */
@media (max-width: 767px) {
  .index-navbar {
    padding: 10px 4%;
  }
  .index-nav-container {
    flex-direction: column;
    gap: 10px;
  }
  .index-logo {
    height: 36px;
  }
  .index-nav-menu {
    width: 100%;
    justify-content: space-around;
    gap: 0;
    font-size: 14px;
  }
  .index-nav-menu a {
    padding-bottom: 4px;
  }
}