/* ========== 导航栏样式 ========== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  padding: 26px 5%;
  background: #ffffff;
  backdrop-filter: blur(12px);
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 9999;
  transition: all 0.5s cubic-bezier(0.34, 0, 0.2, 1);
  box-shadow: none;
}

/* 滚动缩小也无阴影 */
.navbar.shrink {
  padding: 16px 5%;
  box-shadow: none;
}

.navbar.hide {
  transform: translateY(-100%);
  opacity: 0;
}

/* LOGO */
.logo {
  font-size: 21px;
  font-weight: 500;
  color: #000;
  letter-spacing: 2.5px;
  cursor: pointer;
  transition: all 0.32s ease;
  position: relative;
  white-space: nowrap;
}

.logo::before {
  content: '';
  position: absolute;
  left: -12px;
  top: 50%;
  transform: translateY(-50%);
  width: 2px;
  height: 16px;
  background: #000;
  opacity: 0.8;
  transition: all 0.3s ease;
}

.logo:hover {
  transform: scale(1.05);
  letter-spacing: 3px;
}

.logo:hover::before {
  height: 22px;
  opacity: 1;
}

/* 汉堡按钮 */
.hamburger {
  display: none;
  width: 26px;
  height: 20px;
  position: relative;
  background: transparent;
  border: none;
  cursor: pointer;
  z-index: 10000;
}

.hamburger span {
  position: absolute;
  left: 0;
  width: 100%;
  height: 1.5px;
  background: #222;
  transition: all 0.4s cubic-bezier(0.34, 0, 0.2, 1);
}

.hamburger span:nth-child(1) {
  top: 0;
}

.hamburger span:nth-child(2) {
  top: 50%;
  transform: translateY(-50%);
}

.hamburger span:nth-child(3) {
  bottom: 0;
}

.hamburger:hover span:nth-child(2) {
  width: 70%;
}

.hamburger.active span:nth-child(1) {
  top: 50%;
  transform: translateY(-50%) rotate(45deg);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
}

.hamburger.active span:nth-child(3) {
  bottom: 50%;
  transform: translateY(50%) rotate(-45deg);
}

/* 导航默认样式 */
.nav {
  display: flex;
  gap: 50px;
  list-style: none;
  align-items: center;
}

.nav li a {
  color: var(--text-light);
  font-size: 18px;
  font-weight: 400;
  text-decoration: none;
  position: relative;
  letter-spacing: 0.4px;
  transition: all 0.35s cubic-bezier(0.25, 0.8, 0.25, 1);
  white-space: nowrap;
}

.nav li a:hover {
  color: #000;
  font-weight: 500;
  transform: translateY(-2px);
  letter-spacing: 0.8px;
}

.nav li a::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 50%;
  width: 0;
  height: 1px;
  background: #000;
  transform: translateX(-50%);
  transition: all 0.35s cubic-bezier(0.25, 0.8, 0.25, 1);
}

.nav li a:hover::after {
  width: 90%;
}

.nav li a .emoji {
  display: none;
}

/* ========== 返回顶部按钮 ========== */
.back-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: var(--black-color);
  color: var(--white-color);
  border: none;
  font-size: 20px;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all 0.32s cubic-bezier(0.34, 0, 0.2, 1);
  z-index: 998;
  display: flex;
  align-items: center;
  justify-content: center;
}

.back-top.show {
  opacity: 1;
  visibility: visible;
}

.back-top:hover {
  background: #555;
  transform: translateY(-3px) scale(1.05);
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.12);
}

.back-top:active {
  transform: translateY(0);
}

/* ========== 页脚样式 ========== */
/* 页脚整体容器：缩减上下内边距，减少顶部外间距 */
.footer-full {
  background: var(--black-color);
  color: #e0e0e0;
  padding: clamp(15px, 4vw, 25px) 0 clamp(8px, 2vw, 15px);
  margin-top: 20px;
  font-weight: 300;
}

/* 页脚内容包裹：缩减左右内边距、底部间距，保持紧凑 */
.footer-wrap {
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 clamp(8px, 2vw, 15px) clamp(10px, 3vw, 20px);
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: clamp(10px, 2vw, 15px);
  flex-wrap: nowrap;
}

/* 左栏：彻底居中，取消多余外边距 */
.footer-col:nth-child(1) {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

/* 左栏标题：缩减底部间距 */
.footer-col:nth-child(1) h4 {
  margin-bottom: 4px;
  font-size: clamp(16px, 2.5vw, 20px);
  font-weight: 500;
  color: var(--white-color);
  letter-spacing: 0.5px;
}

/* 左栏文字：缩减行高，取消多余外边距 */
.footer-col:nth-child(1) p {
  margin: 0;
  line-height: 1.3;
  font-size: clamp(13px, 2vw, 15px);
  opacity: 0.8;
}

/* 右栏：保持居中，缩减整体间距 */
.footer-col:nth-child(2) {
  text-align: center;
}

/* 右栏标题：与左栏标题间距统一 */
.footer-col:nth-child(2) h4 {
  margin-bottom: 4px;
  font-size: clamp(16px, 2.5vw, 20px);
  font-weight: 500;
  color: var(--white-color);
  letter-spacing: 0.5px;
}

/* 分类列表：缩减项之间的间距，行高紧凑 */
.footer-category {
  display: flex;
  gap: clamp(8px, 1.5vw, 14px);
  justify-content: center;
  padding: 0;
  margin: 0;
  list-style: none;
  flex-wrap: nowrap;
}

/* 分类链接：缩减行高，保持透明度过渡 */
.footer-category li a {
  color: #e0e0e0;
  text-decoration: none;
  font-size: clamp(13px, 2vw, 15px);
  line-height: 1.3;
  opacity: 0.8;
  transition: all 0.3s ease;
  white-space: nowrap;
}

/* hover 效果保持不变 */
.footer-category li a:hover {
  opacity: 1;
  color: var(--white-color);
  text-decoration: underline;
  transform: translateY(-1px);
}

/* 移动端：仅隐藏右栏，保持左栏紧凑居中 */
@media (max-width: 767px) {
  .footer-col:nth-child(2) {
    display: none !important;
  }

  /* 移动端左栏进一步缩减内边距 */
  .footer-full {
    padding: clamp(10px, 3vw, 20px) 0;
  }

  .footer-wrap {
    padding: 0 clamp(5px, 2vw, 10px) clamp(5px, 2vw, 10px);
    margin-bottom: clamp(5px, 1vw, 10px);
  }
}