* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, Helvetica, sans-serif;
}

body {
    color: #fff;
}

/* <============ All Basic Work Start ============> */
.heading-text {
  text-align: center;
  margin: 40px;
  padding: 10px;
  font-size: 35px;
  z-index: 999;
}

.nav {
    height: 80px;
    width: 100%;
    background:	#ffffff;
    display: flex;
    justify-content: space-evenly;
    align-items: center;
    position: fixed;
    top: 0;
    left: 0;
    padding: 20px 40px;
    backdrop-filter: blur(5px);
    transition: all 0.4s ease;
    z-index: 999;
    border-radius: 0;
    box-shadow: 0 4px 12px rgb(255, 255, 255, 0.8);
}

/*mobile navbar scroll **********************/
.nav.scrolled {
    width: 90%;
    left: 50%;
    transform: translateX(-50%); /* page center */
    background: rgba(255, 255, 255, 0.250);
    box-shadow: 0 4px 12px rgba(255, 255, 255, 0.514);
    border-radius: 50px;
    padding: 10px 30px;
    margin-top: 20px;
}

.nav.scrolled .nav-list li a {
  color: white;
}

.nav-logo img {
    width: 80px;
    height: auto;
}

.nav-list li {
    list-style: none;
    display: inline-block;
    margin: 0 15px;
}

.nav-list li a {
    text-decoration: none;
    color: #07002e;
    font-size: 18px;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-list li a:hover {
  transition: ease-in .3s;
  opacity: .4;
}

.mobile-menu {
    display: none;
    font-size: 28px;
    color: #07002e;
    cursor: pointer;
}

.close-icon {
  display: none;
}

#home {
    width: 100%;
    height: 100vh; /* every section hight */
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

.section{
  height: 100vh;
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #000000;
}

.section-content {
    z-index: 1;
    text-align: center;
}

.section-content h2, .section-content p {
    margin: 10px 0;
}

.section-content[contenteditable="true"] {
    border: 1px dashed #fff;
    padding: 10px;
}

/* <============ All Basic Work End ============> */
/* <============ Hero Section Start ============> */

.section-1 {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
}

#animated-text {
  color: #07002e;
  border-radius: 10px;
  margin-bottom: 30px;
  transition: opacity 0.5s ease-in-out;
  font-size: 2.5rem;
  font-weight: bold;
  color: #ffffff;
}

/* search optimigations work style */
.search-container {
  position: relative;
  width: 350px;
  z-index: 2;
}

.search-container input {
  width: 100%;
  padding: 10px 15px;
  font-size: 16px;
  border: 1px solid #ccc;
  border-radius: 25px;
  outline: none;
  transition: border-color 0.2s;
}

.search-container input:focus {
  border-color: rgb(0, 235, 252);
}

.search-container button {
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
  background: transparent;
  border: none;
  cursor: pointer;
  font-size: 18px;
  color: #07002e;
}

.search-container button:hover {
  color: #000;
}

/* ==== Suggestion Box ==== */
.suggestions {
  position: absolute;
  top: calc(100% + 5px);
  width: 100%;
  background: #fff;
  color: #07002e;
  border: 1px solid #ccc;
  border-radius: 5px;
  max-height: 200px;
  overflow-y: auto;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
  display: none; /* fist display none */
  z-index: 1000;
}

.suggestions li {
  list-style: none;
  padding: 10px 15px;
  cursor: pointer;
  transition: background-color 0.2s;
}

.suggestions li:hover,
.suggestions li.active {
  background-color: #07002e;
  color: #fff;
}

/* <============ Hero Section End ============> */
/* <============ Discover Science Section Start ============> */

#discover {
  height: auto;
}

.section-container {
  width: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  z-index: 2;
}

.cards {
  width: 80%;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  grid-template-rows: repeat(auto-fit, minmax(350px, 1fr));
  grid-auto-rows: 1fr;
  justify-content: center;
  gap: 40px;
  perspective: 1000px; /* 3D effect*/
}

.card {
  position: relative;
  background-color: #ffffff;
  border-radius: 8px;
  box-shadow: 0 6px 15px rgba(0, 0, 0, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  color: #0A192F;
  cursor: pointer;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  transform-style: preserve-3d;
}

.card button {
  --border-radius: 15px;
  --border-width: 4px;
  border: 0;
  font-weight: 500;
  z-index: 2;
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background-color: #07002e;
  color: #ffffff;
  padding: 10px 20px;
  border-radius: 50px;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

.card button::after {
 --m-i: linear-gradient(#000, #000);
 --m-o: content-box, padding-box;
 content: "";
 position: absolute;
 left: 0;
 top: 0;
 width: 100%;
 height: 100%;
 padding: var(--border-width);
 border-radius: var(--border-radius);
 background-image: conic-gradient(
		#488cfb,
		#29dbbc,
		#ddf505,
		#ff9f0e,
		#e440bb,
		#655adc,
		#488cfb
	);
 -webkit-mask-image: var(--m-i), var(--m-i);
 mask-image: var(--m-i), var(--m-i);
 -webkit-mask-origin: var(--m-o);
 mask-origin: var(--m-o);
 -webkit-mask-clip: var(--m-o);
 mask-composite: exclude;
 -webkit-mask-composite: destination-out;
 filter: hue-rotate(0);
 animation: rotate-hue linear 500ms infinite;
 animation-play-state: running;
}

/* .card button:hover::after {
 animation-play-state: running;
} */

@keyframes rotate-hue {
 to {
  filter: hue-rotate(1turn);
 }
}

.card button,
.card button::after {
 box-sizing: border-box;
}

.card button:active {
 --border-width: 5px;
}

/* book stack css */
.card::before,
.card::after {
  content: "";
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: 8px;
  background-color: #e0e0e0;
  z-index: -1;
  transition: all 0.3s ease;
  background-repeat: no-repeat;
  background-size: cover;
}

/* 1st layer */
.card::before {
  top: 10px;
  left: 10px;
}

/* 2nd layer middle page */
.card::after {
  top: 5px;
  left: 5px;
}

/* card background img */
.card-1::after {
  background-image: url('img/physics.png');
}

.card-2::after {
  background-image: url('img/chemistry.png');
}

.card-3::after {
  background-image: url('img/biology.png');
}

.card-4::after {
  background-image: url('img/astronomy.png');
}

.card-5::after {
  background-image: url('img/paleontology.png');
}

.card-6::after {
  background-image: url('img/medical_science.png');
}

.card-7::after {
  background-image: url('img/geology.png');
}

.card-8::after {
  background-image: url('img/ai_robotics2.png');
}

.card:hover {
  transform: translateY(-10px) rotateX(5deg) rotateY(-5deg);
  box-shadow: 0 12px 25px rgba(0, 0, 0, 0.2);
}

.card:hover::before {
  top: 5px;
  left: 5px;
  background-color: #d4d4d4;
}

.card:hover::after {
  top: 2px;
  left: 2px;
  background-color: #cccccc;
}

/* <============ Discover Science Section End ============> */
/* <============ Custom Publish Section Start ============> */

#custom-publishing {
  width: 100%;
  height: 80vh;
  padding: 100px 5%;
  color: #fff;
  overflow: hidden;
}


#custom-publishing .custom-publishing-inner {
  height: auto;
  width: 100%;
  position: relative;
  z-index: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: 50px 0;
}

#custom-publishing .cp-title {
  font-size: 1.8rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin: 1.5rem 0;
  font-weight: bold;
}

#custom-publishing .publish-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}

#custom-publishing .publish-card {
  background-color: #1e1e1e;
  border-radius: 6px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform .2s;
}

#custom-publishing .publish-card:hover {
  transform: translateY(-5px);
}

#custom-publishing .publish-card img {
  width: 100%;
  height: 140px;
  object-fit: cover;
}

#custom-publishing .publish-label {
  display: inline-block;
  margin: 0.75rem 1rem 0.25rem;
  font-size: 0.65rem;
  font-weight: bold;
  color: #ff6b6b;
  text-transform: uppercase;
}

#custom-publishing .publish-text {
  flex-grow: 1;
  margin: 0 1rem 1rem;
  font-size: 0.9rem;
  line-height: 1.4;
}

#custom-publishing .cp-viewmore {
  margin-top: 1.5rem;
  text-align: right;
  font-size: 0.9rem;
  cursor: pointer;
  letter-spacing: 0.5px;
}

#custom-publishing .cp-viewmore:hover {
  text-decoration: underline;
}

/* <============ Custom Publish Section End ============> */
/* <============ Video Section Start ============> */

#video-section {
  height: auto;
  display: flex;
  flex-direction: column;
  padding: 20px 20px 100px 20px;
}

.video-heading {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 20px;
  color: #fff;
}

#video-section .video-grid {
  width: 80%;
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 1rem;
  margin-top: 2rem;
  z-index: 2;
}

#video-section .video-column {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

#video-section .video-card {
  border-radius: 10px;
  overflow: hidden;
  position: relative;
}

#video-section .yt-wrapper {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  background: #000;
}
#video-section .yt-wrapper iframe {
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  height: 100%;
  border: none;
}

/* <============ Video Section End ============> */
/* <============ Newsletter Section Start ============> */

.newsletter-section {
  padding: 40px 20px;
  background-color: #000000;
}

.newsletter-container {
  display: flex;
  flex-wrap: wrap;
  gap: 30px;
  justify-content: center;
  max-width: 1200px;
  margin: auto;
  align-items: flex-start;
}

.cover-image {
  flex: 1 1 300px;
  text-align: center;
  z-index: 2;
}

.cover-image img {
  width: 100%;
  max-width: 300px;
  box-shadow: -10px -10px 5px #b6b6b6;
  transition: all 0.3s ease;
}

.cover-image img:hover {
  box-shadow: none;
  transform: translateY(-5px);
  cursor: pointer;
  box-shadow: none;
}

.button-group {
  margin-top: 20px;
}

.button-group button {
  padding: 10px 15px;
  margin-right: 10px;
  border: none;
  background: #eee;
  cursor: pointer;
  border-radius: 4px;
  transition: all 0.3s ease;
}

.button-group button:hover {
  background: #ddd;
}

.toc-button {
  color: rgb(0, 0, 0);
  font-weight: bold;
  background: none;
}

.article-list {
  flex: 2 1 500px;
}

.article {
  margin-bottom: 20px;
  border-bottom: 1px solid #ccc;
  padding-bottom: 10px;
}

.article small {
  font-size: 12px;
  color: gray;
  text-transform: uppercase;
}

.article h4 {
  font-size: 16px;
  margin-top: 5px;
  color: #1a1a1a;
}

.article-card {
  border: 2px solid #5eff00;
}

.other-article-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 20px;
  padding: 20px;
}

.article-card {
  background: #f9f9f9;
  border: 1px solid #eee;
  border-radius: 8px;
  overflow: hidden;
  transition: transform 0.3s ease;
  z-index: 2;
}

.article-card:hover {
  transform: translateY(-5px);
}

.article-card img {
  width: 100%;
  height: 140px;
  object-fit: cover;
  display: block;
}

.article-info {
  padding: 10px;
  text-align: left;
}

.article-info small {
  font-size: 12px;
  color: gray;
  text-transform: uppercase;
}

.article-info h4 {
  font-size: 15px;
  margin-top: 5px;
  color: #111;
}

/* <============ Newsletter Section End ============> */
/* <============ Commentary Section Start ============> */

.commentary {
  width: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background-color: #000;
  color: #fff;
  padding: 40px 20px;
  font-family: Arial, sans-serif;
}

.commentary-title {
  font-size: 2rem;
  font-weight: bold;
  margin-bottom: 30px;
}

.commentary-container {
  width: 80%;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  grid-auto-rows: auto;
  gap: 20px;
}

.commentary-card {
  display: flex;
  background-color: #111;
  border-radius: 6px;
  overflow: hidden;
  transition: transform 0.3s ease;
  cursor: pointer;
  z-index: 2;
}

.commentary-card:hover {
  transform: scale(1.02);
}

.commentary-card img {
  width: 150px;
  height: 100px;
  object-fit: cover;
  flex-shrink: 0;
}

.card-text {
  padding: 10px 15px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.hover-underline {
  position: relative;            /* pseudo-element-এর জন্য রেফারেন্স পজিশন */
  display: inline-block;         /* inline এলিমেন্টের সাপোর্টের জন্য */
}

.hover-underline::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  height: 2px;                   /* লাইন এর পুরুত্ব */
  width: 0;                      /* শুরুতে লাইন নাই */
  background: currentColor;      /* টেক্সটের রঙের সাথে ম্যাচ করবে */
  transition: width 0.3s ease;
}

.hover-underline:hover::after {
  width: 100%;                   /* হোভারে পুরো লাইন শো করবে */
}

.meta {
  font-size: 12px;
  color: #bbb;
  margin-bottom: 6px;
}

.card-text h3 {
  font-size: 16px;
  margin: 0;
  line-height: 1.4;
}

/* মোবাইলে এক কলাম */
@media (max-width: 600px) {
  .commentary-container {
    grid-template-columns: 1fr;
  }
  .commentary-card {
    flex-direction: column;
  }
  .commentary-card img {
    width: 100%;
    height: auto;
  }
}

/* <============ Commentary Section End ============> */
/* <============ Copyright Section Start ============> */

.section_copyright {
  overflow: hidden;
  background-color: #1a1a1a;
  padding: 20px 0;
}

.scroll-track {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: max-content;
  gap: 190px;
  animation: scroll-left 20s linear infinite;
  white-space: nowrap;
}

.scroll-item {
  color: #ccc;
  text-align: center;
  font-family: 'Georgia', serif;
  font-size: 22px;
}

.scroll-item span {
  display: block;
  font-size: 13px;
  color: #888;
}

/* Animation */
@keyframes scroll-left {
  0% {
    transform: translateX(100%);
  }
  100% {
    transform: translateX(-100%);
  }
}

/* <============ Copyright Section End ============> */
/* <============ Footer Section Start ============> */

.footer {
  background-color: #1d1d1d;
  padding: 40px 20px;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 30px;
  max-width: 1200px;
  margin: auto;
}

.footer-column h3 {
  font-size: 14px;
  font-weight: bold;
  margin-bottom: 15px;
  color: #fff;
}

.footer-column ul {
  list-style: none;
  padding: 0;
}

.footer-column ul li {
  margin-bottom: 8px;
  font-size: 14px;
  color: #bbb;
  cursor: pointer;
}

.footer-column ul li:hover {
  color: #fff;
}

.social-icons {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 10px;
}

.social-icons span {
  background: #222;
  border-radius: 50%;
  padding: 10px;
  font-size: 16px;
  cursor: pointer;
  transition: background 0.3s;
}

.social-icons span:hover {
  background: #444;
}

.newsletter-btn {
  margin-top: 15px;
  padding: 10px 15px;
  border: 1px solid #fff;
  background: transparent;
  color: #fff;
  border-radius: 20px;
  cursor: pointer;
  transition: background 0.3s;
}

.newsletter-btn:hover {
  background: #fff;
  color: #000;
}

/******************************** Mobile View *******************************/
@media (max-width: 768px) {
    /* <============ Hero Section Start ============> */
    .nav-list {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 60px;
        right: 20px;
        background: #1b263b;
        border-radius: 8px;
    }

    .mobile-menu {
        display: block;
    }

    .close-icon {
        display: block;
        position: absolute;
        top: 10px;
        right: 15px;
        font-size: 30px;
        padding: 5px 20px;
        cursor: pointer;
        color: #07002e;
        z-index: 1000;
    }

    .nav.scrolled .mobile-menu {
        color: #ffffff;
    }

    .nav-list.active {
        display: flex;
        width: 100%;
        height: auto;
        top: calc(100% + 5px);
        background: #ffffffe5;
        backdrop-filter: blur(5px);
        position: absolute;
        left: 0;
        right: 0;
        color: #07002e;
        overflow-y: auto;
        box-shadow: 0 4px 8px rgba(0,0,0,0.1);
        z-index: 1000;
        text-align: center;
    }

    .nav-list li {
        margin: 10px 0;
        padding: 10px 0;
    }

    .nav-list li:hover,
    .nav-list li:hover a {
        background-color: #07002e;
        color: #fff;
        cursor: pointer;
    }

    .nav.scrolled .nav-list li a{
        color: #000000;
    }

    .nav.scrolled .nav-list li:hover,
    .nav.nav.scrolled .nav-list li:hover a {
        background-color: #07002e;
        color: #fff;
        cursor: pointer;
    }

    .section {
      height: auto;
    }

  /* <============ Hero Section End ============> */
  /* <============ Custom Publish Section Start ============> */

    #custom-publishing {
      height: auto;
    }

    #custom-publishing .publish-card img {
      height: 120px;
    }

    #custom-publishing {
      padding: 40px 3%;
    }

    #custom-publishing .cp-title {
      font-size: 1.3rem;
    }
  /* <============ Custom Publish Section End ============> */
  /* <============ Video Section Start ============> */

    #video-section {
      height: auto;
      padding: 20px;
    }
    #video-section .video-grid {
      grid-template-columns: 1fr;
    }

    #video-section .video-column {
      flex-direction: row;
    }

    #video-section .video-column {
      flex-direction: column;
    }

    /* <============ Video Section End ============> */
    /* <============ Newsletter Section Start ============> */

    .newsletter-section {
      height: auto;
      padding: 20px 10px;
    }
    .newsletter-container {
      flex-direction: column;
      align-items: center;
      text-align: center;
    }

    .article-list {
      width: 100%;
      padding: 0 10px;
    }

    .article h4 {
      font-size: 15px;
    }

  .toc-button {
    display: block;
    margin: 10px auto;
  } 

  /* <============Newsletter section End ============> */
  /* <============ Copyright section Start ============> */

  .scroll-track {
    gap: 30px;
    animation-duration: 15s;
  }

  .scroll-item {
    font-size: 18px;
  }
  /* <============ Copyright section End ============> */
  /* <============ Footer Section Start ============> */

  .footer {
    text-align: center;
  }
  
  .social-icons {
    justify-content: center;
  }
 /* <============ Footer Section End ============> */
};