@import url('https://fonts.googleapis.com/css2?family=Long+Cang&family=Ma+Shan+Zheng&family=Zhi+Mang+Xing&display=swap');
:root {body {

  --bg-dark: linear-gradient(to right, #0f2027, #203a43, #2c5364); 
  --bg-light: linear-gradient(135deg, #f4f6f8, #e0ecf3); 
  --text-dark: #fff;
  --text-light: #ffffff;
  --accent-blue: #007acc;  
  --accent-orange: #FF9800;
  --yellow: #ffd700;
       
}}
  
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  min-height: 100%;
  overflow-x: hidden;
}


 
#themeIcon {
  width: 40px;
  height: 40px;
  stroke-width: 2;
  padding: 6px;
  border-radius: 50%;
  background: rgba(255,255,255,0.1);
  transition: background 0.3s ease, transform 0.3s ease;
  cursor: pointer;
}
#themeIcon:hover {
  background: rgba(255,255,255,0.2);
  transform: scale(1.1);
}



canvas#hanziCanvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: 0;
  pointer-events: none;
  opacity: 0.09; 
}


.logo-wrapper {
  position: relative;
  display: inline-block;
  border-radius: 50%;
  padding: 4px; 
}

.logo-wrapper::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: conic-gradient(from 0deg, #00c6ff, #ff9a00, #00c6ff);
  animation: spinNeon 4s linear infinite;
  z-index: -1;
  filter: blur(3px) brightness(1.4);
}


.logo-wrapper img.logo-img {
  display: block;
  border-radius: 50%;
  height: 49px;
  width: 49px;
  object-fit: contain;
  position: relative;
  z-index: 1;

}
@keyframes spinNeon {
  0% {
    transform: rotate(0deg);
    filter: hue-rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
    filter: hue-rotate(360deg);
  }
}
@media (max-width: 768px) {

  .logo-img {
    width: 36px !important;
    height: 36px !important;
    object-fit: contain !important;
  }
  .logo-wrapper{
    margin-right: 10px !important; 
}
}
.logo-link {
  display: flex;
  align-items: center;
  text-decoration: none;
  gap: 0.5rem;
}
nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: nowrap;
  padding: 0.5rem 1rem; 
  position: sticky;
  top: 0;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
  border-bottom: 1px solid rgba(255, 255, 255, 0.3);
  z-index: 1000;
  transition: background-color 0.3s ease, box-shadow 0.3s ease;
}


.nav-left {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex: 0 0 auto;
}

.nav-menu {
  display: flex;
  list-style: none;
}
.nav-menu li {
  cursor: pointer;
  position: relative;
}









.menu-toggle {
  display: none;
  order: 1;
  margin-left: auto;
  font-size: 1.8rem;
  color: white;
  background: none;
  border: none;
  cursor: pointer;

}


.nav-right {
  order: 2;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}


/* .btn-login {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 40px;
  padding: 0 12px;
  border: 1px solid white;
  border-radius: 6px;
  background: transparent;
  color: white;
  font-size: 0.9rem;
  line-height: normal;
  cursor: pointer;
} */



.main-content {
  min-height: 75vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2rem 1rem;
  text-align: center;
  background: transparent !important;
  overflow:hidden;

}
.main-content h1 {
  font-size: 2rem;
  margin-bottom: 4rem;

}
.buttons {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
}
.btn-start {
  background: var(--accent-blue);
  color: white;
  padding: 1rem 2rem;
  border: none;
  border-radius: 8px;
}
.btn-join {
  background: var(--accent-orange);
  color: white;
  padding: 1rem 2rem;
  border: none;
  border-radius: 8px;
}
.btn-start,
.btn-join {
  padding: 1rem 2rem;
  border: none;
  border-radius: 8px;
  color: white;
  font-weight: 600;
  cursor: pointer;

  
  transition: transform 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
}


.btn-start { background: var(--accent-blue); }
.btn-join  { background: var(--accent-orange); }


.btn-start:hover,
.btn-join:hover {
  
  transform: scale(1.05);
  
  box-shadow: 0 8px 16px rgba(0,0,0,0.2);
}


.btn-start:active,
.btn-join:active {
  
  transform: scale(0.95);
  
  box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

.btn-start:hover {
  background: #005fa3; 
}
.btn-join:hover {
  background: #e67600;
}

.site-footer {
  background: #1c1c1c;
  color: #ccc;
  font-size: 1rem;
  padding:10px;
}
.footer-container {
  width: 100%;
  padding: 5px 1rem;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 2rem;
}
.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.footer-logo {
  font-size: 1.8rem;
  color: var(--yellow);
  font-weight: 600;
}


.footer-brand .dmca-badge img {
  display: block;
  width: 100px;      
  height: auto;
  filter: invert(1); 
}


.footer-brand .dmca-badge:hover {
  transform: scale(1.05);
}

.footer-tagline {
  font-size: 1rem;
}
.footer-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  text-align: right;
  font-size: large;
  background:transparent;
  z-index:0
}
.footer-nav a {
  color: #ccc;
  text-decoration: none;
  position: relative;
  padding: 0 0.5rem;
  font-size: 1rem;
  flex-direction: row;
}
.footer-nav > a:not(.social-link):not(:last-child)::after {
  content: "|";
  position: absolute;
  right: 0;
  color: #555;
}
.footer-nav a:hover {
  color: white;
}
.social-links {
  display: flex;
  gap: 3rem;
  margin-top: 1rem;
}
.social-links img {
  width: 24px;
  height: 24px;
  filter: invert(1);
  cursor: pointer;
}




.site-footer {
  border-top: none !important;
  margin: 0;
  padding-bottom: 0;
}

.footer-nav {
  margin-right: 1rem;     
}


.main-content {
  background: transparent !important;
}


main, .main-content, .footer-container {
  border: none !important;
}


.social-links a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.2s ease, filter 0.2s ease, box-shadow 0.2s ease;
  border-radius: 50%;
  padding: 0.4rem;
}


.social-links svg,
.social-links img {
  width: 26px;
  height: 26px;
  color: ghostwhite;
  transition: transform 0.2s ease, filter 0.2s ease;
}


.social-links a:hover {
  transform: scale(1.1);
  filter: brightness(1.6);
  box-shadow: 0 0 8px rgba(255, 255, 255, 0.4); 
}


.social-links a:active {
  transform: scale(0.95);
  filter: brightness(1.8);
}
.flip-btn {
  perspective: 1000px;
  width: 200px;
  height: 70px;
  margin: 1rem;
  display: inline-block;
  position: relative;
  overflow: hidden;
  border-radius: 12px;
  isolation: isolate;
}

.flip-inner {
  position: relative;
  width: 100%;
  height: 100%;
  text-align: center;
  transition: transform 0.6s ease;
  transform-style: preserve-3d;
}

.flip-btn:hover .flip-inner {
  transform: rotateY(180deg);
}

.flip-front {
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: 12px;
  backface-visibility: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 1.1rem;
  color: white;
  z-index: 2; 
  pointer-events: auto; 
  cursor: pointer; 
}

.flip-back {
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: 12px;
  backface-visibility: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 1.1rem;
  color: white;
  z-index: 1;
}

.flip-front {
  background: var(--accent-blue);
}

.btn-join.flip-front {
  background: var(--accent-orange);
}

.flip-back {
  background: #333;
  transform: rotateY(180deg);
}

.sparkle-star {
  position: absolute;
  color: #fff;
  font-size: 14px;
  pointer-events: none;
  animation: sparkle-blink 2s infinite ease-in-out;
  filter: drop-shadow(0 0 4px white);
  opacity: 0;
  z-index: 1002;
}

@keyframes sparkle-blink {
  0%, 100% {
    transform: scale(0.2) rotate(0deg);
    opacity: 0;
  }

  50% {
    transform: scale(1.6) rotate(180deg);
    opacity: 1;
  }
}

canvas#hanziCanvas {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
}
.sparkle {
  position: fixed;
  width: 8px;
  height: 8px;
  background: white;
  border-radius: 50%;
  box-shadow: 0 0 8px white;
  animation: sparkle-blink 0.6s ease-out forwards;
  z-index:1002;
}
@keyframes sparkle-blink {
  0% { transform: scale(0.2); opacity: 1; }
  100% { transform: scale(1.4); opacity: 0; }
}



#toastArea {
  position: fixed;
  bottom: 4rem;
  right: 1rem;
  z-index: 99999999;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.toast {
  background: #333;
  color: white;
  padding: 0.75rem 1.25rem;
  border-radius: 8px;
  box-shadow: 0 4px 10px rgba(0,0,0,0.2);
  animation: slideInFade 0.5s ease;
  z-index:99999999;
  font-size:18px;
}
@keyframes slideInFade {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* 
#loginBtn, #registerBtn {
  padding: 0.5rem 1rem;
  background: var(--accent-blue, #007acc);
  color: white;
  border: none;
  border-radius: 8px;
  font-weight: bold;
  cursor: pointer;
  transition: background 0.3s ease;
  box-shadow: -1px 1px 15px 10px rgba(0, 0, 0, 0.2);
}
#registerBtn {
  background: var(--accent-orange, #FF9800);
}
#loginBtn:hover {
  background: #005fa3;
}
#registerBtn:hover {
  background: #e67600;
}

.btn-login {
  background: transparent;
  color: white;
  border: 1px solid white;
  border-radius: 6px;
  padding: 8px 14px;
  cursor: pointer;
  margin-left: 0.5rem;
  transition: background 0.3s;
}
.btn-login:hover {
  background: rgba(255, 255, 255, 0.1);
} */


#toastArea {
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.toast {
  background: rgba(0,0,0,0.8);
  color: white;
  padding: 12px 18px;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
  font-size: 0.95rem;
  line-height: 1.4;
  max-width: 300px;
  animation: toastFadeIn 0.4s ease, toastFadeOut 0.4s ease 2.5s;
}

@keyframes toastFadeIn {
  from {
    opacity: 0;
    transform: translateX(50px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}
@keyframes toastFadeOut {
  to {
    opacity: 0;
    transform: translateX(100px);
  }
}



/* 
#loginBtn, #registerBtn {
  padding: 0.5rem 1rem;
  background: #007acc;
  color: white;
  border: none;
  border-radius: 8px;
  font-weight: bold;
  cursor: pointer;
  transition: background 0.3s ease;
} */
/* 
#loginBtn:hover {
  background: #005fa3;
}


#registerBtn {
  background: #ff9800;
}

#registerBtn:hover {
  background: #e67600;
}


#userToggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  padding: 6px 12px;
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.1);
  color: white;
  font-weight: 600;
  transition: background 0.3s;
}
#userToggle:hover {
  background: rgba(255, 255, 255, 0.2);
} */

/* 
#avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid white;
  margin-left: 0.5rem;
}


#userDropdown {
  position: absolute;
  top: calc(100% + 8px); 
  right: 165px; 
  margin-top: 8px; 
  background: #222;
  color: white;
  border-radius: 8px;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
  overflow: hidden;
  z-index: 999;
  display: none; 
  min-width: 180px;
}

#userDropdown.show {
  display: block;
}
#userDropdown a {
  display: block;
  padding: 12px 16px;
  color: white;
  text-decoration: none;
  transition: background 0.2s;
}
#userDropdown a:hover {
  background: rgba(255, 255, 255, 0.1);
}
 */
/* 
#toastArea {
  position: fixed;
  bottom: 1rem;
  right: 1rem;
  z-index: 10000;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.toast {
  background: rgba(0, 0, 0, 0.85);
  color: white;
  padding: 0.75rem 1.25rem;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
  font-size: 0.95rem;
  line-height: 1.4;
  animation: fadeInOut 3s ease forwards;
}
@keyframes fadeInOut {
  0% { opacity: 0; transform: translateY(20px); }
  10% { opacity: 1; transform: translateY(0); }
  90% { opacity: 1; }
  100% { opacity: 0; transform: translateY(-20px); }
}



#main-title-container {
  position: relative;
  display: inline-block;
  width: 100%;
  text-align: center;
  margin-bottom: 1rem;
}





 */


@keyframes shine {
  0% { background-position: 0% 50%; }
  100% { background-position: 200% 50%; }
}

@keyframes blink-caret {
  0%, 100% { opacity: 0; }
  50% { opacity: 1; }
}


.sparkle-star {
  position: absolute;
  color: #fff;
  font-size: 14px;
  pointer-events: none;
  animation: sparkle-blink 2.5s infinite ease-in-out;
  filter: drop-shadow(0 0 4px white);
  opacity: 0;
  z-index: 10;
}

@keyframes sparkle-blink {
  0%, 100% {
    transform: scale(0.2) rotate(0deg);
    opacity: 0;
  }
  50% {
    transform: scale(1.6) rotate(180deg);
    opacity: 1;
  }
}






html[data-theme="dark"] .footer-nav {
  background: transparent !important;
  box-shadow: none !important;
}


.hidden {
  display: none !important;
}


  
@media (min-width: 769px) {
  html[data-theme="light"] .nav-right,
  html[data-theme="dark"] .nav-right {
    box-shadow: none !important;
    background: transparent !important;
    padding: 4px;
  }
  html[data-theme="dark"] .logo-title {
      font-size: 24px;
      font-weight: 700;
      background: linear-gradient(to right, #FF9800, #f9a825);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      color: transparent;
      margin: 1;
      white-space: nowrap;
}
 
   html[data-theme="dark"] .menu-link {
    color: #fbfbfb
   }
   #userDropdown {
    position: absolute !important;
    top: calc(86% + 10px);
    left: 70%;
    background: #222;
    color: white;
    border-radius: 8px;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
    overflow: hidden;
    z-index: 999;
    display: none;
    width: max-content;
}
  #userDropdown.show {
    display: block;
  }

  #userDropdown a {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 16px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    color: white;
    text-decoration: none;
    white-space: nowrap;
  }

  #userDropdown a:last-child {
    border-bottom: none;
  }

  #userDropdown a:hover {
    background: rgba(255, 255, 255, 0.1);
  }
}



html[data-theme="light"] {
  
  nav {
    background: rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.25);
    transition: background-color 0.3s ease;
  }

  
  .nav-right {
    background: #ffffff;
    border-radius: 20px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
    border: 1px solid rgba(255, 255, 255, 0.3);
  }

  
  .main-content {
    background-color: rgba(255, 255, 255, 0.85); 
    padding: 2rem;
    border-radius: 12px;
    backdrop-filter: blur(1px);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.05);
  }
  
  [data-theme="dark"] .main-content {
    background-color: rgba(30, 30, 30, 0.85);
    box-shadow: 0 4px 16px rgba(255, 255, 255, 0.05);
    color: #f1f1f1;
  }
  .nav-menu li a {
    position: relative;
    text-decoration: none;
    color:#007acc
  }

  .nav-menu li a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 10%;
    width: 0;
    height: 2px;
    background: transparent;
    transition: width 0.3s ease, background 0.3s ease;
  }

  .nav-menu li a:hover::after {
    width: 80%;
    background: #007ACC;
  }

  
  .logo-title {
    --c-primary: #4d8bff;
    --c-bg-card: rgba(255, 255, 255, 0.35);
    --card-w: 300px;
    --card-h: 380px;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --border: #e2e8f0;
    --shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.15);
    --header-height: 71px;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    padding: 0;
    box-sizing: border-box;
    font-size: clamp(1rem, 2.2vw, 1.25rem);
    line-height: 1.05;
    font-weight: 700;
    background: var(--gradient, linear-gradient(135deg, var(--primary-color, #2563eb), var(--secondary-color, #7c3aed)));
    background-clip: text;
    color: transparent;
    white-space: nowrap;
    display: inline-block;
    margin: 0;
  }


  
  #themeIcon .sun-core {
    fill: url(#sunGradient);
  }

  #themeIcon .sun-rays line {
    stroke: url(#sunGradient);
    opacity: 1;
  }

  
  .site-footer {
    background: rgba(10, 15, 20, 0.96);
    color: #2c2c2c;
    border-top: 1px solid rgba(190, 210, 230, 0.3);
  }

  .footer-tagline {
    color: #ffffff;
    font-size: 1rem;
    opacity: 0.9;
  }

  .footer-nav {
    background: transparent;
  }

  .footer-nav a {
    color: #ffffff;
    background: transparent !important;
  }

  .footer-nav a:hover {
    color: var(--accent-blue);
  }

  .footer-brand .dmca-badge img {
    filter: none;
  }
}




html[data-theme="dark"] {
  background: linear-gradient(to right, #0f1b27, #182c3d, #223f55);
  color: #f0f0f0;

  /* Navigation */
  nav {
    background: rgba(23, 34, 47, 0.9) !important; 
    backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    transition: background-color 0.3s ease;
  }

  /* Side menu */
  .nav-right.show {
    background: rgba(15, 22, 30, 0.95); 
    backdrop-filter: blur(8px);
    border-left: 1px solid rgba(255, 255, 255, 0.05);
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
  }

  /* Menu toggle */
  .menu-toggle {
    background: none; 
    border-radius: 6px;
    transition: all 0.3s ease;
    padding: 16px;
  }

  /* Main content */
  .main-content {
    background: rgba(15, 25, 35, 0.7);
    backdrop-filter: blur(10px);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.08);
    transition: background 0.3s ease, color 0.3s ease;
  }

  /* Theme icon */
  #themeIcon .sun-core {
    fill: #e0e0e0;
  }

  #themeIcon .sun-rays line {
    stroke: #e0e0e0;
    opacity: 0;
  }

  /* Buttons */
  .btn-start,
  .btn-join {
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
  }

  .btn-start:hover,
  .btn-join:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.4);
    filter: brightness(1.1);
  }

  /* Footer */
  .site-footer {
    background: rgba(10, 15, 20, 0.98);
    color: #ccc;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
  }

  .footer-nav a {
    color: #bbb;
    background: transparent !important;
    transition: color 0.2s ease;
  }

  .footer-nav a:hover {
    color: #fff;
  }

  .footer-tagline {
    color: #ffffff;
    font-size: 1rem;
    opacity: 0.85;
  }

  .footer-brand .dmca-badge img {
    filter: invert(1);
  }
  
  /* Carousel cards */
  .carousel-card {
    background: rgba(30, 40, 55, 0.65);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
    border: 1px solid rgba(255, 255, 255, 0.1);
  }
  
  .carousel-card.active {
    box-shadow: 0 0 25px rgba(77, 139, 255, 0.4), 0 0 50px rgba(0, 0, 0, 0.3);
  }
  
  /* User interface elements */
  #userToggle {
    background: rgba(40, 50, 70, 0.5);
    border: 1px solid rgba(255, 255, 255, 0.1);
  }
  
  #userToggle:hover {
    background: rgba(60, 70, 90, 0.5);
  }
}
#username {
  color: #007ACC;
  font-weight: bold;
  font-size: 0.95rem;
}

html[data-theme="dark"] #username {
  color: #ffffff;
  font-weight: bold;
  font-size: 0.95rem;
}
@media (max-width: 768px) {
  .main-content h1 {font-size: 1.6rem!important}

  
  nav {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem 1rem;
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(8px);
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
    border-bottom: 1px solid rgba(200, 200, 200, 0.3);
  }

  
  .menu-toggle {
    display: block;
    font-size: 1.8rem;
    color: grey;
    border: none;
    border-radius: 4px;
    padding: 18px;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 2001;
    cursor: pointer;
  }
  .menu-toggle.active {
    color: #007ACC;
  }
  .menu-toggle span {
    display: block;
    width: 24px;
    height: 3px;
    margin: 5px auto;
    background-color: #007ACC;
    border-radius: 2px;
    transition: all 0.3s ease;
  }

  
  .nav-right {
    position: fixed;
    top: 0;
    left: -100%;
    width: 280px;
    height: 100vh;
    z-index: 2000;
    background: linear-gradient(to bottom, #ffffff, #f9fafb);
    backdrop-filter: blur(8px);
    border-top-right-radius: 20px;
    border-bottom-right-radius: 20px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
    padding: 1rem 1.5rem;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    transition: left 0.3s ease-in-out;
    align-items:flex-start;
    
  }
  .nav-right.show {
left: 0;
    height: 100vh;
    z-index: 1;
  }

  
  .nav-menu {
    display: flex;
    flex-direction: column;
    gap: 1.8rem;
    padding: 0;
    margin-top: 2rem!important;
  }
  .menu-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-weight: bold;
    font-size: 1.1rem;
    color: var(--menu-text);
    background: transparent;
    border-radius: 8px;
    cursor: pointer;
    width: 100%;
    transition: background 0.3s ease;
  }
  .menu-item:hover {
    background: var(--menu-hover-bg);
  }
  .menu-link {
    flex-grow: 1;
    text-decoration: none;
    color: inherit;
  }
  .main-content {
    min-height: calc(95vh - 5rem);
    /* display: flex; */
    /* flex-direction: column; */
    /* align-items: center; */
    /* justify-content: center; */
    padding: 1rem 1rem;
    /* text-align: center; */
    /* background: transparent !important; */
    /* overflow: hidden; */
}
  .toggle-submenu {
    font-size: 1.2rem;
    user-select: none;
    margin-left: 0.5rem;
    color: var(--accent-blue);
  }
/* ─── NÚT MỞ / ĐÓNG SUBMENU ───────────────────────────── */

/* 0. Phần tử chính: biến thành khối bấm 32×32 px */
.toggle-submenu{
  position: relative;
  display: inline-block;
  width: 2rem;                 /* 32 px */
  height: 2rem;
  margin-left: .5rem;          /* tách khỏi chữ */
  cursor: pointer;
}

/* 1. Vòng tròn nền */
.toggle-submenu::after{
  content:'#';
  position:absolute;
  inset: 0;                     /* phủ kín 32×32 px */
  border: 2px solid currentColor;
  border-radius:50%;
  background:#fff;              /* nền trắng; bỏ nếu không cần */
  transition: background .15s;
  margin: 5px;
  text-align: center;
}

/* 2. Chevron */
.toggle-submenu::before{
  content:'!';                  /* đóng */
  position:absolute;
  left:50%; top:50%;
  transform:translate(-50%,-50%);
  font-size:1rem;
  font-weight:800;
  line-height:1;
  pointer-events:none;          /* sự kiện vẫn ở phần tử chính */
}

/* 3. Khi mở */
.menu-item.has-children.open>.toggle-submenu::before{
  content:'!';                  /* mở */
}
.menu-item.has-children.open>.toggle-submenu::after{
  background: currentColor;     /* nền tô nhẹ */
  opacity:.12;
}

  
  .menu-level {
    display: none;
    flex-direction: column;
    width: 100%;
    padding-left: 1.5rem;
    margin-top: 0.5rem;
    gap: 0.4rem;
  }
  .menu-item.open > .menu-level {
    display: flex;
    animation: slideDown 0.3s ease forwards;
  }

  .menu-level .menu-item {
    font-size: 1rem;
    font-weight: normal;
    padding: 0.4rem 0.8rem;
    background: transparent;
    border-left: 2px solid var(--accent-blue);
    border-radius: 0;
  }
  .menu-level .menu-item:hover {
    background: var(--menu-hover-bg);
  }
  .nav-right {
    height: 100dvh;
    overflow-y: auto; 
    overscroll-behavior: contain; 
  }

  
  @keyframes slideDown {
    from { opacity: 0; transform: translateY(-8px); }
    to { opacity: 1; transform: translateY(0); }
  }

  
  #userToggle {
    width: 100%;
    margin-top: 2rem;
    padding: 12px 16px;
    font-size: 1rem;
    font-weight: bold;
    text-align: left;
    border-radius: 10px;
    background: white;
    color: #007ACC;
    border: 1px solid #007ACC;
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
  }
  #langBtn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 2px; 
    padding: 0.3rem;
    border-radius: 8px;
    border: 2px solid black; 
    background: #fff;         
    height: 40px;
    min-width: 120px;
    flex-wrap: nowrap;
    box-sizing: border-box;
  }
  
  
  html[data-theme="dark"] #langBtn {
    background: #2a2a3a;
    border-color: #888;
  }
  
  #userDropdown {
    position: static !important;
    width: 100%;
    background: rgba(34, 34, 34, 0.9);
    border-radius: 8px;
    margin-top: 0.5rem;
    overflow: hidden;
    opacity: 0;
    max-height: 0;
    visibility: hidden;
    transition: all 0.4s ease;
  }
  #userDropdown.show {
    max-height: 600px;
    opacity: 1;
    visibility: visible;
    min-height: 200px;
}
  #userDropdown a {
    display: block;
    padding: 12px 16px;
    color: white;
    text-decoration: none;
    border-bottom: 1px solid rgb(255, 255, 255, 0.1);
  }
  #userDropdown a:last-child {
    border-bottom: none;
  }

  

  body.sidebar-open {
    overflow: hidden;
    height: 100dvh;
  }

  
  :root {
    --accent-blue: #007ACC;
    --menu-text: #222;
    --menu-hover-bg: rgb(0, 122, 204, 0.07);
  }

    [data-theme="dark"] {
      --menu-bg: #1e1e2e;
      --menu-hover-bg: rgba(255,255,255,0.1);
      --menu-text: #e0e0e0;
      --accent-blue: #4ea9ff;
    }
  
    html[data-theme="dark"] .nav-right {
      background: linear-gradient(to bottom, #1a1a2a, #222);
      box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
    }
  
    html[data-theme="dark"] .menu-toggle {
      color: #eee;
    }
    html[data-theme="dark"] .menu-toggle.active {
      color: #00c6ff;
    }
  
    html[data-theme="dark"] .menu-level {
      background: none;
    }
  
    html[data-theme="dark"] .menu-item,
    html[data-theme="dark"] .menu-link {
      color: var(--menu-text);
    }
  
    html[data-theme="dark"] .menu-item:hover {
      background: var(--menu-hover-bg);
    }
  
    html[data-theme="dark"] #userToggle {
      background: #2a2a2a;
      color: var(--accent-blue);
      border: 1px solid #4ea9ff;
    }
  
    html[data-theme="dark"] #userDropdown {
      background: #2a2a2a;
    }
  
    html[data-theme="dark"] #userDropdown a {
      color: #eee;
      border-color: rgba(255,255,255,0.1);
    }
  
    html[data-theme="dark"] #langBtn {
      background: #2a2a3a;
      border-color: #888;
    }
    html[data-theme="dark"] .logo-title {
     color: #ffd700;
      border-color: #fafafa;
    }
  }
.typing-text {
  color: var(--main-title-color);
  text-shadow: 1px 1px 2px rgba(0,0,0,0.1);
}

#langBtn {

  height: 40px;
  overflow: hidden;
  border-radius: 10px;
  border: none!important;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.lang-btn-inline {
  all: unset;
  text-align: center;
  font-weight: bold;
  cursor: pointer;
  font-size: 14px;
  padding: 0.5rem 0;
  background: white;
  color: black;
  border-right: 1px solid #ccc;
  transition: background 0.2s ease, color 0.2s ease;
}

.lang-btn-inline:last-child {
  border-right: none;
}

.lang-btn-inline:hover {
  background: #f0f0f0;
}

.lang-btn-inline.active {
  background: #007ACC;
  color: white;
}


.theme-switch {
  position: relative;
  display: inline-flex;       
  align-items: center;
  justify-content: center;
  width: 80px;
  height: 40px;
  vertical-align: middle;
  flex-shrink: 0;                 

}

.theme-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  display: inline-flex;       
  justify-content: space-between;
  align-items: center;
  background: #eee;
  border-radius: 40px;
  padding: 0 10px;
  position: relative;
  height: 100%;
  width: 100%;
  box-shadow: inset 2px 2px 6px #ccc, inset -2px -2px 6px #fff;
  transition: background 0.3s;
  cursor: pointer;
}

.slider::before {
  content: "";
  position: absolute;
  height: 34px;
  width: 34px;
  left: 3px;
  top: 3px;
  border-radius: 50%;
  background: linear-gradient(to bottom, #f9a825, #fbc02d);
  box-shadow: 2px 2px 6px rgba(0, 0, 0, 0.2);
  transition: transform 0.4s, background 0.4s;
  z-index: 1;
}

.icon {
  width: 20px;
  height: 20px;
  stroke: #555;
  stroke-width: 2;
  z-index: 2;
  pointer-events: none;
}

input:checked + .slider {
  background: #ddd;
}

input:checked + .slider::before {
  transform: translateX(40px);
  background: linear-gradient(to bottom, #78909c, #90a4ae);
}


@media (min-width: 769px) {
  
  .nav-menu {
    display: flex;
    list-style: none;
    padding: 0;
    margin: 0;
    position: relative;
    z-index: 999;
  }

  .menu-item {
    position: relative;
    font-size: 1.05rem;
    font-weight: 600;
    white-space: nowrap;
  }

  .menu-link {
    display: block;
    padding: 0.6rem 0.8rem;
    color: #2266c1;
    text-decoration: none;
    border-radius: 8px;
    transition: background 0.2s;
  }

  .menu-link:hover {
    background: none;
  }

  
  .menu-item.has-children > .menu-level {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    flex-direction: column;
    background: #f5f9ff;
    padding: 0.5rem 0;
    min-width: 200px;
    border-radius: 12px;
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
    list-style: none!important;
  }
  html[data-theme="dark"] .menu-item.has-children > .menu-level {
    background:rgba(10, 15, 20, 0.96);
    backdrop-filter: blur(10px) ;
    
  }

  .menu-item.has-children:hover > .menu-level {
    display: flex;
  }

  .menu-level .menu-item {
    padding: 0;
  }

  .menu-level .menu-link {
    padding: 0.5rem 1rem;
    font-weight: 500;
    font-size: 0.95rem;
  }

  
  .menu-level .menu-item.has-children {
    position: relative;
  }

  .menu-level .menu-item.has-children > .menu-level {
    top: 0;
    left: 100%;
    margin-left: 0rem;
    display: none;
    flex-direction: column;
    position: absolute;
    background: #f5f9ff;
    border-radius: 10px;
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
    min-width: 200px;
    padding: 0.4rem 0;
  }

  .menu-level .menu-item.has-children:hover > .menu-level {
    display: flex;
  }

  
  .menu-item.has-children > .menu-link::after {
    content: '';
    font-size: 0.75rem;
    margin-left: 0.3rem;
    vertical-align: middle;
  }

  .menu-level .menu-item.has-children > .menu-link::after {
    content: '▶';
    float: right;
    font-size: 0.75rem;
    margin-left: 0.5rem;
    transform: translateY(1px);
  }
}


/* =========================================================
   CAROUSEL  –  Glass • 3‑D • Responsive
   ========================================================= */


:root{
  --c-primary : #4d8bff;
  --c-bg-card : rgba(255,255,255,.35);   
  --card-w    : 300px;                   
  --card-h    : 380px;
}

@media (max-width:768px){
  :root{ --card-w: 250px; --card-h: 280px; }
  .footer-brand {
    display: flex;
    flex-direction: column;
    gap: 0rem;
    align-content: center;
    justify-content: center;
    align-items: center;
    flex-wrap: nowrap;
}
}


.carousel-container{
  position:relative;
  width:100%;
  max-width:1200px;
  margin-inline:auto;
  padding-block:4rem 6rem;        
  display:flex;
  justify-content:center;
  align-items:center;
  z-index:231 ‑ 1;        
  height:400px;
}

.carousel-wrapper{
  position:relative;
  display:flex;
  justify-content:center;
  align-items:center;
  width:100%;
  height:100%;
  perspective:1200px;             
  touch-action:pan-y;             
}


.carousel-card{
  position:absolute;
  top:50%; left:50%;
  translate:-50% -50%;            
  width:var(--card-w);
  height:var(--card-h);
  padding:2rem 1.6rem 2.4rem;
  display:flex;
  flex-direction:column;
  justify-content:center;
  align-items:center;
  text-align:center;

  background:var(--c-bg-card);
  backdrop-filter:blur(14px) saturate(1.25);
  -webkit-backdrop-filter:blur(14px) saturate(1.25);
  border-radius:1.6rem;
  box-shadow:0 25px 55px rgba(0,0,0,.12);

  transform:translateX(-50%) scale(.75) rotateY(15deg);
  opacity:.25;
  filter:blur(2px);
  pointer-events:none;            
  transition:
    transform .55s ease,
    opacity   .55s ease,
    filter    .55s ease;
}

.carousel-card h2{
  margin:0 0 .35rem;
  font-size:1.6rem;
  font-weight:700;
  line-height:1.2;
}

.carousel-card p{
  margin:.35rem 0 1.7rem;
  font-size:.96rem;
  color:#444;
}




.carousel-start-btn{
  padding:.75rem 2.4rem;
  border:none;
  border-radius:1rem;
  background:var(--c-primary);
  color:#fff;
  font-size:1rem;
  font-weight:600;
  cursor:pointer;
  transition:transform .25s, background .25s;
  box-shadow:none;                     
  position:relative;
}
.carousel-start-btn:hover{ transform:scale(1.05); }


.carousel-card.active{
  transform:translateX(-50%) scale(1) rotateY(0deg);
  opacity:1;
  filter:none;
  pointer-events:auto;
  z-index:3;
  cursor: pointer;

}


.carousel-card.left{
  transform:translateX(-180%) scale(.8) rotateY(10deg);
  opacity:.4; filter:blur(1px); z-index:2;
}
.carousel-card.right{
  transform:translateX(80%) scale(.8) rotateY(-10deg);
  opacity:.4; filter:blur(1px); z-index:2;
}


.carousel-nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  font-size: 2.8rem;
  font-weight: bold;
  color: transparent;
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  z-index: 999;

  background-clip: text;
  -webkit-background-clip: text;

  background-image: linear-gradient(145deg, #555, #aaa, #eee);
  text-shadow:
    0 0 6px rgba(0, 0, 0, 0.1),
    0 0 10px rgba(255, 255, 255, 0.3);

}

.carousel-nav:hover {
  background: none;
  transform: translateY(-50%) scale(1.1);
  opacity: 1;

  background-image: linear-gradient(145deg, #00f0ff, #8effff);
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;

  text-shadow:
    0 0 6px rgba(0, 255, 255, 0.5),
    0 0 12px rgba(0, 255, 255, 0.7),
    0 0 18px rgba(0, 255, 255, 1);
}

.carousel-prev {
  left: clamp(24px, 6vw, 48px);
}

.carousel-next {
  right: clamp(24px, 6vw, 48px);
}

.carousel-prev{                       
  left:clamp(24px,3vw,60px);
}
.carousel-next{                       
  right:clamp(24px,3vw,60px);
}


/* @media (max-width:768px){
  .carousel-nav{font-size:2rem;}
  .carousel-prev {
    left: clamp(0px, 0vw, 0px);
  }
  .carousel-next {
    right: clamp(0px, 0vw, 0px);
  }
  .carousel-container{      
    height:200px!important;
  };
  .footer-container {
    width: 100%;
    padding: 1rem;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 2rem;
  }
  .footer-container {
    width: 106%;
    padding: 1rem;
    display: flex;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 2rem;
    justify-content: center!important;
}
} */


.carousel-start{
  display:inline-block;
  margin-top:2rem;
  padding:.85rem 3.8rem;
  border:none;
  border-radius:1.15rem;
  background:var(--c-primary);
  color:#fff;
  font-size:1.15rem;
  font-weight:600;
  cursor:pointer;
  box-shadow:0 6px 18px rgba(0,0,0,.18);
  transition:transform .22s;
}
.carousel-start:hover{ transform:translateY(-3px); }


@media (prefers-color-scheme:dark){
  :root{ --c-bg-card:rgba(38,38,38,.45); }
  .carousel-card p{ color:#ddd; }
}

.card-bg-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border-radius: 1.5rem;
  z-index: 0;
  cursor: pointer;
}
.visually-hidden {
  position: absolute !important;
  height: 1px; width: 1px;
  overflow: hidden;
  clip: rect(1px, 1px, 1px, 1px);
  white-space: nowrap;
}
.carousel-card .card-content {
  position: relative;
  z-index: 1;
}
.hsk-logo .hsk-text {
  font-size: 4rem;
  font-weight: bold;
  color: #007806;
  letter-spacing: 0.1rem;
  text-shadow: 1px 2px 1px white;
}
.hsk-logo {
  text-align: center;
  font-family: 'Georgia', serif;
  margin-bottom: 1rem;
}
.hsk-logo small {
  font-size: 1rem;
  color: rgba(10, 15, 20, 0.96);
  display: block;
  border-top: 1px solid #aaa;
  padding-top: 0.25rem;
  margin-top: 0.25rem;
}
.card-logo {
  text-align: center;
  margin-bottom: 1rem;
}
.card-logo img {
  max-height: 60px;
  max-width: 100%;
  object-fit: contain;
}






.theme-0 .card-title {
  color: #007f9e; 
}

.theme-0 .card-description {
  color: #ffffff;
  text-shadow: 1px 1px 1px #222;
  font-weight: 900;
}

.theme-0 .card-bg-canvas {
  background: radial-gradient(
    circle at 40% 40%,
    rgba(0, 176, 255, 0.35),
    rgba(153, 102, 255, 0.15),
    transparent
  );
}
.carousel-card.theme-0.active {
  box-shadow: 0 0 20px rgba(76, 175, 80, 0.6), 0 0 60px rgba(76, 175, 80, 0.25);
  border: 1px solid rgba(76, 175, 80, 0.3);
}
.theme-1 .card-title {
  color: #4AA8F2; 
  font-weight: 700;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.25);
}

.theme-1 .card-description {
  color: rgba(255, 255, 255, 0.85); 
  font-weight: 500;
  text-shadow: 0 0 4px rgba(0, 0, 0, 0.2);
}

.theme-1 .card-bg-canvas {
  background: radial-gradient(
    circle at 50% 50%,
    #A9D1F7,  
    #CCC96A,  
    transparent
  );
}

.carousel-card.theme-1.active {
  box-shadow: 0 0 20px #4AA8F2, 0 0 40px rgba(74, 168, 242, 0.4);
  border: 1px solid rgba(74, 168, 242, 0.5);
}

.button {
  font-weight: 700;         
text-shadow: 0 1px 2px rgba(0, 0, 0, 0.25);  
letter-spacing: 0.5px;    
  --primary: linear-gradient(135deg, #007ACC, #4FC3F7);
  --primary-dark: #2055EE;
  --primary-darkest: #133FC0;
  --text: #FFFFFF;
  --text-opacity: 1;
  --success: #2B3044;
  --success-scale: .2;
  --success-opacity: 0;
  --border-radius: 7;
  --overflow: hidden;
  --rotate: 0;
  --plane-x: 0;
  --plane-y: 0;
  --plane-opacity: 1;
  --left-wing-background: var(--primary);
  --left-wing-first-x: 0;
  --left-wing-first-y: 0;
  --left-wing-second-x: 50;
  --left-wing-second-y: 0;
  --left-wing-third-x: 0;
  --left-wing-third-y: 100;
  --left-body-background: var(--primary);
  --left-body-first-x: 50;
  --left-body-first-y: 0;
  --left-body-second-x: 50;
  --left-body-second-y: 100;
  --left-body-third-x: 0;
  --left-body-third-y: 100;
  --right-wing-background: var(--primary);
  --right-wing-first-x: 50;
  --right-wing-first-y: 0;
  --right-wing-second-x: 100;
  --right-wing-second-y: 0;
  --right-wing-third-x: 100;
  --right-wing-third-y: 100;
  --right-body-background: var(--primary);
  --right-body-first-x: 50;
  --right-body-first-y: 0;
  --right-body-second-x: 50;
  --right-body-second-y: 100;
  --right-body-third-x: 100;
  --right-body-third-y: 100;
  display: block;
  cursor: pointer;
  position: relative;
  border: 0;
  padding: 10px 0;
  min-width: 100px;
  text-align: center;
  margin: 30px 0 0 0;
  line-height: 24px;
  font-family: inherit;
  font-weight: 900;
  font-size: 18px;
  background: none;
  outline: none;
  color: var(--text);
  transform: rotate(calc(var(--rotate) * 1deg)) translateZ(0);
  -webkit-appearance: none;
  appearance:none;
  -webkit-tap-highlight-color: transparent;
  .left,
  .right {
      position: absolute;
      left: 0;
      top: 0;
      right: 0;
      bottom: 0;
      opacity: var(--plane-opacity);
      transform: translate(calc(var(--plane-x) * 1px), calc(var(--plane-y) * 1px)) translateZ(0);
      &:before,
      &:after {
          content: '';
          position: absolute;
          left: 0;
          top: 0;
          right: 0;
          bottom: 0;
          border-radius: calc(var(--border-radius) * 1px);
          transform: translate(var(--x, .4%), var(--y, 0)) translateZ(0);
          z-index: var(--z-index, 2);
          background: var(--background, var(--left-wing-background));
          clip-path: polygon(calc(var(--first-x, var(--left-wing-first-x)) * 1%) calc(var(--first-y, var(--left-wing-first-y)) * 1%), calc(var(--second-x, var(--left-wing-second-x)) * 1%) calc(var(--second-y, var(--left-wing-second-y)) * 1%), calc(var(--third-x, var(--left-wing-third-x)) * 1%) calc(var(--third-y, var(--left-wing-third-y)) * 1%));
      }
  }
  .left:after {
      --x: 0;
      --z-index: 1;
      --background: var(--left-body-background);
      --first-x: var(--left-body-first-x);
      --first-y: var(--left-body-first-y);
      --second-x: var(--left-body-second-x);
      --second-y: var(--left-body-second-y);
      --third-x: var(--left-body-third-x);
      --third-y: var(--left-body-third-y);
  }
  .right:before {
      --x: -.4%;
      --z-index: 2;
      --background: var(--right-wing-background);
      --first-x: var(--right-wing-first-x);
      --first-y: var(--right-wing-first-y);
      --second-x: var(--right-wing-second-x);
      --second-y: var(--right-wing-second-y);
      --third-x: var(--right-wing-third-x);
      --third-y: var(--right-wing-third-y);
  }
  .right:after {
      --x: 0;
      --z-index: 1;
      --background: var(--right-body-background);
      --first-x: var(--right-body-first-x);
      --first-y: var(--right-body-first-y);
      --second-x: var(--right-body-second-x);
      --second-y: var(--right-body-second-y);
      --third-x: var(--right-body-third-x);
      --third-y: var(--right-body-third-y);
  }
  span {
      display: block;
      position: relative;
      z-index: 4;
      opacity: var(--text-opacity);
      &.success {
          z-index: 0;
          position: absolute;
          left: 0;
          right: 0;
          top: 8px;
          transform: rotate(calc(var(--rotate) * -1deg)) scale(var(--success-scale)) translateZ(0);
          opacity: var(--success-opacity);
          color: var(--success);
      }
  }
}

html {
  box-sizing: border-box;
  -webkit-font-smoothing: antialiased;
}

* {
  box-sizing: inherit;
  &:before,
  &:after {
      box-sizing: inherit;
  }
}

.button::after {
  content: '';
  position: absolute;
  top: 0;
  left: -75%;
  width: 50%;
  height: 100%;
  background: linear-gradient(
    120deg,
    rgba(255, 255, 255, 0.2) 0%,
    rgba(255, 255, 255, 0.8) 50%,
    rgba(255, 255, 255, 0.2) 100%
  );
  transform: skewX(-25deg);
  pointer-events: none;
}

html[data-theme="dark"] .button::after {
  background: none;
}

.button:hover::after {
  animation: shine 1s ease forwards;
}

@keyframes shine {
  to {
    left: 125%;
  }
}
.hsk-logo.theme-1 {
  background: linear-gradient(135deg, #A9D1F7, #CCC96A); 
  padding: 2px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 72px;
  height: 72px;
  box-shadow: 0 0 12px rgba(0, 0, 0, 0.25);
  position: relative;
}

.hsk-logo.theme-1::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 50%;
  padding: 4px;
  background: #0C1020; 
  z-index: 1;
}

.hsk-logo.theme-1 .hsk-text {
  position: relative;
  z-index: 2;
  font-weight: 700;
  font-size: 16px;
  background: linear-gradient(90deg, #4AA8F2, #1AC4A8);
  -webkit-background-clip: text;
  background-clip:text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 1px 2px rgba(0,0,0,0.3);
}

.hsk-logo.theme-1 small {
  position: absolute;
  bottom: -16px;
  width: 100%;
  text-align: center;
  font-size: 12px;
  color: #ffffff;
  opacity: 0.7;
  z-index: 2;
}
.hsk-text.theme-1 {
  font-size: 2.5rem;
  font-weight: bold;
  letter-spacing: 0.05rem;
  background: linear-gradient(90deg, #4AA8F2, #1AC4A8); 
  -webkit-background-clip: text;
  background-clip:text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 1px 2px rgba(0,0,0,0.3);
}




.footnav\&social {
  display: flex;
  flex-direction: column;
  flex-wrap: nowrap;
  align-content: center;
  justify-content: center;
  align-items: center;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0rem;
}


.footnav\&social {
  display: flex;
  flex-direction: column;
  flex-wrap: nowrap;
  align-content: center;
  justify-content: center;
  align-items: center;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0rem;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

div#stats {
  display: flex;
  flex-wrap: nowrap;
  color: white;
  align-items: flex-start;
  align-content: flex-start;
  flex-direction: column-reverse;
  justify-content: flex-end;
  gap: 0.5rem
}
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.main-content.not-found {
  min-height: 70vh;
  text-align: center;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 1rem;
  z-index: 10;
}


.main-content.not-found h1 {
  font-size: 5rem;
  background: linear-gradient(360deg, #3c0404, #f7f7f7);
  color: transparent;
  margin: 0;
  background-clip: text;
}

.main-content.not-found .gif {
    max-width: 40%;
    height: 40%;
}

.main-content.not-found a {
  display: inline-block;
  background: var(--accent-blue);
  color: rgb(255, 255, 255);
  padding: 0.75rem 1.5rem;
  border-radius: 6px;
  font-weight: bold;
  text-decoration: none;
  transition: background 0.3s ease;
}
.main-content.not-found a:hover {
  background: #005fa3;
}
.main-content.not-found p {
  font-size: 1.8rem;
  color: transparent;
  margin: 0;
  background: linear-gradient(123deg, #010000, #222);
  background-clip: text;
}
html[data-theme="light"] .main-content {
    background-color: rgba(255, 255, 255, 0.85);
    padding: 2rem;
    border-radius: 12px;
    backdrop-filter: blur(4px);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.05);
}

html[data-theme="dark"].main-content.not-found p {
    font-size: 1.8rem;
    color: #84787800;
    margin: 0;
    background: linear-gradient(360deg, #ffbdbd, #ffffff);
    background-clip: text;
}

.carousel-card.theme-2.active .card-description {
  color: #d4edff;
  font-size: 1rem;
  font-weight: 600;
  font-family: "fantasy", ui-sans-serif, monospace, sans-serif;;
}


.card-icon {
  display: block;
  margin: 0 auto 12px auto;
  filter: drop-shadow(0 0 10px rgba(0, 255, 255, 0.6))
          drop-shadow(0 0 15px rgba(255, 0, 128, 0.4));
  animation: siriPulse 2.5s ease-in-out infinite, siriRotate 10s linear infinite;
  transform-origin: center;
}

@keyframes siriPulse {
  0%, 100% {
    transform: scale(1);
    opacity: 1;
    filter: drop-shadow(0 0 10px rgba(0, 255, 255, 0.6))
            drop-shadow(0 0 15px rgba(255, 0, 128, 0.4));
  }

  50% {
    transform: scale(1.08);
    opacity: 0.95;
    filter: drop-shadow(0 0 20px rgba(0, 255, 255, 0.9))
            drop-shadow(0 0 25px rgba(255, 0, 128, 0.6));
  }

}

@keyframes siriRotate {
  0% {
    transform: rotate(0deg);
  }

  100% {
    transform: rotate(360deg);
  }
  
}



.carousel-card:hover {
  transform: scale(1.03);
  box-shadow: 0 12px 32px rgb(0, 0, 0, 0.25);
  z-index: 2;
}


.carousel-card.theme-2.active .card-description {
  color: #550000;
  font-size: 1rem;
  font-weight: 600;
  font-family: ui-sans-serif, monospace, sans-serif, "fantasy";
}



.card-title {
  font-size: 24px;
  font-weight: bold;
  margin-bottom: 12px;
  color: #fff;
}

.card-description {
  font-size: 16px;
  line-height: 1.4;
  text-align: center;
  max-width: 90%;
  color: #f5f5f5;
}
.carousel-card.neon {
  box-shadow:
    0 0 10px rgba(0, 255, 255, 0.7),
    0 0 20px rgba(155, 0, 255, 0.5),
    0 0 40px rgba(255, 0, 128, 0.4);
  border: 2px solid rgba(255, 255, 255, 0.25);
}

.carousel-card.theme-2.active .card-title {
  color: #ffffff;
  text-shadow: -5px 1px 1px #060606a3;
  font-size: 2rem;
}




.card-ribbon {
  position: absolute;
  top: 12px;
  right: -40px;
  transform: rotate(45deg);
  background: #e53935;
  color: white;
  padding: 10px 60px;
  font-weight: bold;
  font-size: 18px;
  text-align: center;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
  z-index: 10;
  pointer-events: none;
  border-radius: 100px 100px 0px 100px;
}

.hot-star-badge {
  position: absolute;
  top: -20px;
  left: -20px;
  font-size: 24px;
  font-weight: bold;
  color: #ff3333;
  text-shadow: 0 0 8px rgba(255, 80, 80, 0.8), 0 0 15px rgba(255, 80, 80, 0.6);
  transform: rotate(-10deg);
  z-index: 10;
  animation: popHotStar 1.5s infinite ease-in-out;
  pointer-events: none; /* để không chặn click bên dưới */
}

@keyframes popHotStar {
  0%, 100% { transform: scale(1) rotate(-10deg); }
  50% { transform: scale(1.1) rotate(-8deg); }
}

/* Nút chuông thông báo */
#notificationBtn {
  cursor: pointer;
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 10px;
  border-radius: 6px;
  transition: background 0.2s;
}
#notificationBtn:hover {
  background: rgba(0, 0, 0, 0.05);
}

/* Popup dropdown */
#notificationPopup {
  position: fixed;
  top: 10%;
  right: 0;
  margin-top: 8px;
  width: 400px;
  max-width: 90vw;
  background: #fff;
  border: 1px solid #ddd;
  border-radius: 8px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
  z-index: 9999;
  display: none;
  max-height: 500px;
  overflow: hidden;
}

#notificationPopup .dropdown-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: bold;
  margin-bottom: 8px;
  padding: 12px 16px;
  border-bottom: 1px solid #eee;
  background: #f8f9fa;
}

#notificationPopup .dropdown-close {
  background: transparent;
  border: none;
  font-size: 18px;
  cursor: pointer;
  color: #555;
  padding: 4px;
}

#notificationPopup .dropdown-list {
  list-style: none;
  padding: 0;
  margin: 0;
  max-height: 300px;
  overflow-y: auto;
}

#notificationPopup .dropdown-item {
  padding: 12px 16px;
  border-bottom: 1px solid #f0f0f0;
  font-size: 14px;
  color: #333;
  cursor: pointer;
  transition: background 0.2s ease;
}

#notificationPopup .dropdown-item:hover {
  background: #f8f9fa;
}

#notificationPopup .dropdown-item:last-child {
  border-bottom: none;
}

#notificationPopup .dropdown-footer {
  border-top: 1px solid #eee;
  padding: 12px 16px;
  text-align: center;
  background: #f8f9fa;
}

.notif-badge {
  background: #ff4444 !important;
  color: white !important;
  font-size: 10px !important;
  padding: 2px 5px !important;
  border-radius: 10px !important;
  font-weight: bold !important;
  z-index: 1000 !important;
  position: absolute !important;
  top: -6px !important;
  right: -6px !important;
}

@media (max-width: 768px) {
  #notificationPopup {
    position: fixed;
    top: 60px;
    left: 10px;
    right: 10px;
    width: auto;
    max-width: none;
  }
  
  .menu-toggle .notif-badge {
    position: relative !important;
    top: 0 !important;
    right: 0 !important;
    margin-left: 6px !important;
    display: inline-block !important;
  }
}

html[data-theme="dark"] #notificationPopup {
  background: #2a2a2a;
  border-color: #444;
  color: #eee;
}

html[data-theme="dark"] #notificationPopup .dropdown-header,
html[data-theme="dark"] #notificationPopup .dropdown-footer {
  background: #333;
  border-color: #444;
}

html[data-theme="dark"] #notificationPopup .dropdown-item {
  color: #eee;
  border-color: #444;
}

html[data-theme="dark"] #notificationPopup .dropdown-item:hover {
  background: #444;
}

.cursor-help {
  cursor: help !important;
}
.cursor-help *,
.cursor-help *:hover,
.cursor-help button,
.cursor-help button:hover,
.cursor-help a,
.cursor-help a:hover {
  cursor: help !important;
}

.quizzman-logo-card {
  text-align: center;
  color: #fff;
  font-family: 'SF Pro Display', 'Helvetica Neue', Arial, sans-serif;
  margin-bottom: 12px;
}

.quizzman-logo-card .q-icon {
  font-size: 80px;
  font-weight: 700;
  letter-spacing: -2px;
  margin-bottom: 5px;
}

.quizzman-logo-card .title {
  font-size: 32px;
  font-weight: 600;
  letter-spacing: 1px;
}

.quizzman-logo-card .subtitle {
  font-size: 14px;
  opacity: 0.7;
  margin-top: 4px;
  letter-spacing: 1px;
}



.learning-logo-card {
  text-align: center;
  color: #fff;
  font-family: 'SF Pro Display', 'Helvetica Neue', Arial, sans-serif;
  margin-bottom: 12px;
}

.learning-logo-card .l-icon {
  font-size: 64px;
  margin-bottom: 5px;
}

.learning-logo-card .title {
  font-size: 28px;
  font-weight: 600;
  letter-spacing: 1px;
}

.learning-logo-card .subtitle {
  font-size: 14px;
  opacity: 0.7;
  margin-top: 4px;
  letter-spacing: 1px;
}



.button-diff, .button-gramm, .button-idioms {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  padding: 1.1rem 1.5rem;
  width: 100%;
  font-size: 1.1rem;
  font-weight: 600;
  border-radius: 12px;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.25s ease;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.04);
}

.button-diff {
  background: #ffffff;
  border: 1px solid #e0e0e0;
  color: #222;
}

.button-gramm {
  background: #ffffff;
  border: 1px solid #e0e0e0;
  color: #1a3f8b;
}

.button-idioms {
  background: #ffffff;
  border: 1px solid #e0e0e0;
  color: #7d1f6c;
}

.button-diff:hover, .button-gramm:hover, .button-idioms:hover {
  background: #f9f9f9;
  box-shadow: 0 6px 14px rgba(0, 0, 0, 0.06);
  transform: translateY(-1px);
}

.button-diff:active, .button-gramm:active, .button-idioms:active {
  transform: translateY(0);
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
}

.button-diff svg, .button-gramm svg, .button-idioms svg {
  flex-shrink: 0;
}