nav.m_nav {
  position: fixed;
  top: 0;
  left: 0;
  z-index: -1;
  overflow: hidden;
  overflow-y: scroll;
  transform: translateY(115%);
  width: 100vw;
  height: calc(100vh - 5rem);
  border-bottom: 1px solid #ffffff;
  transition: all 600ms cubic-bezier(0.8, 0, 0.33, 1);
}

nav.m_nav::-webkit-scrollbar {
  width: 0;
  background: rgba(255, 255, 255, 0.3);
}
nav.m_nav.nav-open {
  background: #ffffff;
  z-index: 9991;
  transform: translateY(0);
}

/* 菜单按钮通用样式 */
.menu-btn {
  position: fixed;
  cursor: pointer;
  z-index: 99992;
  transition: 0.3s all;
}

/* 菜单按钮内部线条容器样式，设置宽度和高度，并指定背景颜色为黄色（可根据需求调整） */
.menu-btn .lines {
  position: relative;
  width: 1.5rem; /* 24/16，这里可以考虑用更合适的单位，比如 rem 方便响应式布局 */
  height: 1.5rem; /* 24/16 */
}

/* 当导航处于打开状态时，菜单按钮的定位和背景设置 */
.nav-open.menu-btn {
  background: none;
  top: 0.6875rem;
  right: 0.5625rem;
  position: fixed;
}

/* 菜单按钮内部每条线的通用样式，设置背景色、高度、圆角以及过渡效果 */
.menu-btn .line {
  position: absolute;
  background: var(--base_color);
  height: 3px;
  border-radius: 0.625rem; /* 10/16 */
  overflow: hidden;
  transition: 0.3s all;
}

/* 第一条线的初始宽度和位置设置 */
.menu-btn .line.line-1 {
  width: 1.5rem; /* 24/16 */
  top: 50%;
  left: 50%;
  margin-left: -50%;
  margin-top: -0.625rem /* -10/16 */;
}

/* 当添加 line-cross 类时，第一条线旋转并移动到交叉的位置 */
.menu-btn .line.line-1.line-cross {
  margin: 0;
  width: 1.875rem /* 30/16 */;
  transform: translate(-50%, -50%) rotate(45deg);
}

/* 第二条线的初始宽度和位置设置 */
.menu-btn .line.line-2 {
  width: 1rem; /* 16/16 */
  top: 50%;
  left: 50%;
  margin-left: -50%;
  margin-top: -0.125rem /* -2/16 */;
}

/* 当添加 line-fade-out 类时，第二条线宽度变为0且透明度变为0，实现消失效果 */
.menu-btn .line.line-2.line-fade-out {
  width: 0;
  opacity: 0;
}

/* 第三条线的初始宽度和位置设置 */
.menu-btn .line.line-3 {
  width: 1.5rem; /* 24/16 */
  top: 50%;
  left: 50%;
  margin-left: -50%;
  margin-top: 0.375rem /* 6/16 */;
}

/* 当添加 line-cross 类时，第三条线旋转并移动到交叉的位置 */
.menu-btn .line.line-3.line-cross {
  margin: 0;
  width: 1.875rem /* 30/16 */;
  transform: translate(-50%, -50%) rotate(-45deg);
}

nav.m_nav .nav-links {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  transform: translateY(0);
  opacity: 0;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}
nav.m_nav .nav-links .navtop {
  width: 100%;
}
nav.m_nav .nav-links.fade-in {
  opacity: 1;
  transform: translateY(0);
}

nav.m_nav .nav-links .logo_name {
  height: 3.75rem /* 60/16 */;
  font-size: 1.5rem;
  font-weight: bold;
  background-color: #efefef;
  color: var(--grey1);
}

@media (min-width: 992px) {
  a.menu-btn,
  .nav-open a.menu-btn {
    background: none;
    color: unset;
    position: relative;
  }
  .nav-open .menu-btn {
    display: block !important;
  }

  nav.m_nav {
    width: 100vw;
    height: 100vh;
    border-bottom: 0;
  }
}

@media (min-width: 1400px) {
	nav.m_nav .nav-links .logo_name {
	  height: 7.5rem /* 120/16 */;
	}
  }

@media (min-width: 1536px) {
  nav.m_nav .nav-links .logo_name {
    height: 7.5rem /* 120/16 */;
  }
}

nav.m_nav .hedear_slogan p:nth-child(1) {
  font-size: 0.875rem;
}
nav.m_nav .hedear_slogan p:nth-child(2) {
  font-size: 0.875rem;
}

nav.m_nav .navsub {
  display: none;
  font-size: 1.125rem;
}
nav.m_nav .nav-item {
  cursor: pointer;
}
nav.m_nav .nav-item .link {
  width: 100%;
  font-size: 1.25rem;
  border-bottom: 1px solid #eee;
  padding: 1.0625rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
nav.m_nav .nav-item .link.active {
  background-color: var(--base_color);
  color: #ffffff;
}
nav.m_nav .nav-item .link.active > a {
  color: #ffffff;
}

nav.m_nav .nav-item div.link:after {
  content: "\e7e7";
  font-family: "iconfont2022";
}

nav.m_nav .nav-item:first-child:hover .link {
  background: none;
}
nav.m_nav .nav-item:last-child .link {
  border-bottom: none;
}
nav.m_nav .nav-item.active .link {
  background-color: #efefef;
}
nav.m_nav .nav-item.active .navsub {
  background-color: #fafafa;
}

nav.m_nav .nav-item:hover .link,
.nav-item.active .link {
  color: #ffffff !important;
  background: var(--base_color) !important;
}
nav.m_nav .nav-item:hover .link a,
.nav-item.active .link a {
  color: #ffffff;
  background: var(--base_color);
}
nav.m_nav .nav-item.active .link:after {
  transform: rotate(135deg);
  transition: 0.2s all linear;
}
nav.m_nav .nav-item.active .link a {
  font-weight: bold;
}
nav.m_nav .nav-item.active .navsub {
  display: block;
}
nav.m_nav .nav-item.active .navsub a {
  animation: fadeIn 0.5s;
  width: 100%;
  padding: 1.0625rem 0;
  line-height: 1.2;
}
nav.m_nav .nav-subitem {
  overflow: hidden;
  padding: 0 1.875rem;
  color: #444444;
  border-bottom: 1px solid rgba(0, 0, 0, 0.1);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
nav.m_nav .nav-subitem a {
  display: block;
}
nav.m_nav .nav-subitem a.active,
nav.m_nav .nav-subitem a:hover,
nav.m_nav .nav-subitem a.active {
  color: var(--base_color);
}

nav.m_nav .navbottom {
  color: #ffffff;
  background: var(--base_color);
  border-top: 1px solid var(--base_color);
  position: relative;
  margin-top: 0.625rem;
  padding: 0.625rem 0;
  transform: translateY(100%);
}
nav.m_nav .navbottom:after {
  content: "";
  position: absolute;
  z-index: 9;
  right: 0;
  top: 0;
  bottom: 0;
  width: 0;
  height: 0;
  transform: translateY(-100%);
}
nav.m_nav .navbottom a {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 0.625rem 0.625rem;
  font-size: 1.75rem;
  border-bottom: 1px solid rgba(0, 0, 0, 0.3);
  color: #ffffff;
}
nav.m_nav .navbottom a:last-child {
  border-bottom: none;
}
nav.m_nav .navbottom {
  transform: translateY(0);
  transition: all 1000ms cubic-bezier(0.8, 0, 0.33, 1);
}
nav.m_nav .navbottom a i {
  font-size: 1.75rem !important;
  margin-right: 1rem;
}