* {
    #margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

html:after {
    background: transparent linear-gradient(to bottom, rgba(245, 245, 245, 0) 0%, #f5f5f5 100%) repeat scroll 0 0;
    bottom: 0;
    content: "";
    height: 150px;
    left: 0;
    position: fixed;
    right: 0;
}


::-moz-selection {
  background: #E1DCFF;
  text-shadow: none;
}

::selection {
  background: #E1DCFF;
  text-shadow: none;
}

/* Scrollbar width */
::-webkit-scrollbar {
  width: 9px;
}

/* Track */
::-webkit-scrollbar-track {
  box-shadow: inset 0 0 5px grey; 
  border-radius: 10px;
}
 
/* Handle */
::-webkit-scrollbar-thumb {
  background: #3a326a; 
  border-radius: 10px;
  transition: 0.3s;
}

/* Handle on hover */
::-webkit-scrollbar-thumb:hover {
  background: #53479D; 
}

body {
    font-size: 1.25rem;
    line-height: 1.4;
    font-family: "HelveticaNeue-Light", "Helvetica Neue Light", "Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif;
    font-weight: 300;
    background:none transparent;
    margin: 0;
}

body:not(.home) {
    max-width: 800px;
    margin: 1rem auto;
}



    b, strong {
        font-weight: bold;
    }
    
    figcaption,
    cite {
        font-size: 1.05rem;
    }
    
    .page-title,
    h1, h2, h3, h4, h5 {
      font-family: "Oswald", sans-serif;
      font-optical-sizing: auto;
      font-weight: bold; #400;
      font-style: normal;
    }
        h3 {
            font-size: 1.8rem;
        }

.content-container {
    max-width: 800px;
    margin: 1rem auto;
}
    .content-container a {
          transition: color 0.3s;
        color: #7b6dd1;
        text-decoration: none;
        border-bottom: 1px dashed;
    }
    .content-container ul { 
        margin-left: 1.2rem;
    }
    .content-container li { margin: 0.3em 0; }

.home nav a {
    #margin: 0 1rem 0 0;
}

    .navbar {
      background-color: #3a326a; #1a1a1a;
      padding: 1rem 1.5rem;
      position: sticky;
      top: 0;
      z-index: 1000;
      box-shadow: 0 2px 10px rgba(0,0,0,0.5);
    }
    
    .navbar img { display: none; }

    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      max-width: 1200px;
      margin: 0 auto;
    }

    .logo {
      color: white;
      font-size: 2.1rem;
      #font-weight: bold;
      text-decoration: none;
      font-family: "Meow Script", cursive;
      font-weight: 400;
      font-style: normal;
      transition: color 0.3s;
      min-width: 270px;
    }

    .logo span {
      color: #00d4ff;
    }

.nav-menu {
  display: flex;
  gap: 2rem;
  list-style: none;
  align-items: center;
}

    .nav-menu a {
      color: white;
      text-decoration: none;
      font-weight: 500;
      transition: color 0.3s;
      position: relative;
      display: block;
    }

    .dau-an .nav-menu > a:nth-child(2),
    .gioi-thieu .nav-menu > a:nth-child(1),
    .content-container a:hover,
    .logo:hover,
    .nav-menu a:hover {
      color: #00d4ff;
    }

    .content-container  > a::after,
    .nav-menu > a::after {
      content: '';
      position: absolute;
      width: 0;
      height: 2px;
      bottom: -6px;
      left: 0;
      background-color: #00d4ff;
      transition: width 0.3s;
    }

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

    /* Hamburger Menu */
    .hamburger {
      display: none;
      flex-direction: column;
      cursor: pointer;
      gap: 5px;
    }

    .hamburger span {
      width: 25px;
      height: 3px;
      background-color: white;
      border-radius: 3px;
      transition: all 0.3s;
    }

    /* Mobile checkbox hack */
    .submenu-checkbox,
    #menu-toggle {
      display: none;
    }

#btn_top {
    display: none;
  border: none; /* Remove borders */
  outline: none; /* Remove outline */
  #background-color: red; /* Set a background color */
    cursor: pointer;  
    background: #F0F0F0;
    border-radius: 50%;
    padding: 5px;  
    opacity: 0.9;
}
.page-title {
    color: #fff;
    display: none;
    #font-style: italic;
    font-size: 1.5rem;
    font-weight: 300;
} 
    
/* Submenu Styles */
.nav-item {
    position: relative;
}
.has-submenu > .nav-link {
    padding: 1.5rem 0;
    color: white;
}

.submenu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  background-color: #3a326a; #2a2a2a;
  list-style: none;
  min-width: 200px;
  border-radius: 4px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
  z-index: 1000;
  width: 250px;
}

    .submenu li {
      width: 100%;
    }

    .submenu .nav-link,
    .submenu a {
      padding: 0.75rem 1.5rem;
    }

    .submenu .nav-link:hover {
      background-color: #130e30;
    }

    /* Show submenu on hover (desktop) */
    .nav-item:hover > .submenu {
      display: block;
    }

    .has-submenu > .nav-link::after {
        content: '▼';
        margin-left: 0.5rem;
        font-size: 0.8rem;
        transition: transform 0.3s;
      }
     .has-submenu label.nav-link:hover ~ .nav-link::after {
        transform: rotate(180deg);
      }

.site-footer {
    text-align: center;
}

.no-scroll {
  overflow: hidden;
}

/* Mobile styles */
@media (max-width: 768px) {

    body {
        margin: 0 !important;
    }
    .content-container {
        margin: 0 1.5rem;
    }
    img { max-width: 100% }

      .hamburger {
        display: flex;
      }
        .navbar img { display: block; }

      .nav-menu {
        position: fixed;
        display: flex !important;
        top: 70px;
        left: -100%;
        height: 100vh;
        width: 100%;
        #background-color: #3a326a; #1a1a1a;
        flex-direction: column;
        align-items: center;
        justify-content: start;
        padding-top: 2rem;
        transition: left 0.4s ease;
        gap: 3rem;
        
        background: #3a326a url('images//hoang-huu-thuong.jpg') no-repeat center 80%;
      }

      /* Submenu in mobile - accordion style with checkbox */
      .submenu {
        position: static;
        display: block; #none;
        #background-color: #2a2a2a;
        box-shadow: none;
        border-radius: 0;
        padding: 0;
        margin: 0;
      }

      .submenu-checkbox {
        display: none;
      }

      /* Show submenu when checked */
      .submenu-checkbox:checked ~ .submenu {
        display: block;
      }

      /* Style the parent link as toggle */
      .has-submenu .nav-link {
        display: flex;
        justify-content: center;
        align-items: center;
        position: relative;
        padding: 0.8rem 0;
      }

      .submenu-checkbox:checked ~ .nav-link::after {
        transform: rotate(180deg);
      }

      /* Remove hover for submenu on mobile */
      .nav-item:hover > .submenu {
        #display: none; /* Override desktop hover */
      }


      #menu-toggle:checked ~ .nav-menu {
        left: 0;
      }

      #menu-toggle:checked ~ .hamburger span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
      }

      #menu-toggle:checked ~ .hamburger span:nth-child(2) {
        opacity: 0;
      }

      #menu-toggle:checked ~ .hamburger span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
      }
      
      
      /* submenu item animation */
      .nav-menu > a, 
      .nav-item {
          #width: 100%;
          text-align: center;
          opacity: 0;
          transition: opacity 0.5s ease-in-out;
          display: inline-block;
        }

    #menu-toggle:checked ~ .nav-menu > a,
    #menu-toggle:checked ~ .nav-menu .nav-item {
      opacity: 1;
    }

    /* Staggered fade-in delays for main menu items */
    #menu-toggle:checked ~ .nav-menu a:nth-child(1),
    #menu-toggle:checked ~ .nav-menu .nav-item:nth-child(1) {
      transition-delay: 0.1s;
    }
    #menu-toggle:checked ~ .nav-menu a:nth-child(2),
    #menu-toggle:checked ~ .nav-menu .nav-item:nth-child(2) {
      transition-delay: 0.2s;
    }
    #menu-toggle:checked ~ .nav-menu a:nth-child(3),
    #menu-toggle:checked ~ .nav-menu .nav-item:nth-child(3) {
      transition-delay: 0.3s;
    }
    #menu-toggle:checked ~ .nav-menu a:nth-child(4),
    #menu-toggle:checked ~ .nav-menu .nav-item:nth-child(4) {
      transition-delay: 0.4s;
    }
    #menu-toggle:checked ~ .nav-menu a:nth-child(5),
    #menu-toggle:checked ~ .nav-menu .nav-item:nth-child(5) {
      transition-delay: 0.5s;
    }
    
    .page-title { display: none !important }
      
      
      
}