* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
   -webkit-tap-highlight-color: transparent; /*Stops default flash*/
}

/*Stops default flash*/
/* সব elements এর tap highlight বন্ধ */
/* {-webkit-tap-highlight-color: transparent;}*/

/* button, link click flash বন্ধ */
button,
a,
input,
textarea,
select {
  outline: none;
  -webkit-tap-highlight-color: transparent;
}

/* active/focus state remove */
button:focus,
button:active,
a:focus,
a:active {
  outline: none;
  box-shadow: none;
}

body {
  font-family: 'Inter', system-ui, sans-serif;
  line-height: 1.7;
  color: #222;
  background: #f8f9fa;
}

h1, h2, h3 {
  font-family: 'Playfair Display', serif;
}

.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 30px;
}

/* ==================== HEADER ==================== */
.header {
  background: #0f172a;
  color: white;
  padding: 20px 0;
  position: sticky;/**/
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 15px rgba(0,0,0,0.1);
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Logo + Text */

.header-left {
  display: flex;
  align-items: center;
}

.logo-link {
  text-decoration: none;
  color: inherit;
  transition: all 0.3s ease;
}

.logo {
  display: flex;
  align-items: center;
  gap: 16px;
}

.logo img {
  height: 52px;
  width: 52px;
  transition: transform 0.4s ease;
}



.logo h1 {
  font-size: 2rem;
  white-space: nowrap;
  letter-spacing: 1.2px;
  margin: 0;
  line-height: 1.1;
  color: white;
  transition: color 0.3s ease;
}

.logo span {
  color: #00b4d8;
}





/* Hover Effect */
.logo-link:hover .logo img {
  transform: scale(1.08);
}

.logo-link:hover .logo h1 {
  color: #f0f0f0;
}

.logo-link:hover .logo span {
  color: #00d4f0;
}






/* Submit Button */
.btn-primary {
  background: #00b4d8;
  color: white;
  padding: 12px 28px;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 600;
  transition: all 0.3s;
}

.btn-primary:hover {
  background: #0099b8;
  transform: translateY(-2px);
}

/* ==================== HERO ==================== */
.hero {
  background: linear-gradient(135deg, #0f172a, #1e3a8a);
  color: white;
  text-align: center;
  padding: 140px 20px 100px;
}

.hero h2 {
  font-size: 1.4rem;
  letter-spacing: 3px;
  opacity: 0.9;
}

.hero h1 {
  font-size: 4.2rem;
  margin: 15px 0 20px;
}

.tagline {
  font-size: 1.35rem;
  max-width: 700px;
  margin: 0 auto 30px;
  opacity: 0.95;
}



/* ==================== RESPONSIVE ==================== */
@media (max-width: 992px) {
  .hero h1 {
    font-size: 3.4rem;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 15px;
  }
}


/* =========================
   NAVIGATION
========================= */

.nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav a {
  color: #ddd;
  text-decoration: none;
  font-weight: 500;
  transition: 0.3s ease;
  position: relative;
}

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

/* Smooth Scroll */
html {
  scroll-behavior: smooth;
}

















/* ==================== PAPERS SECTION ==================== */
.papers-section {
  padding: 100px 0;
  background: white;
}

.section-title {
  text-align: center;
  font-size: 2.6rem;
  margin-bottom: 60px;
  color: #0f172a;
}

.papers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(520px, 1fr));
  gap: 30px;
}

.paper-card {
  background: #fff;
  border: 1px solid #e5e7eb;
  border-radius: 12px;
  padding: 32px;
  box-shadow: 0 8px 25px rgba(0,0,0,0.06);
  transition: all 0.3s;
}

.paper-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 15px 35px rgba(0,0,0,0.1);
}

.paper-meta {
  display: flex;
  justify-content: space-between;
  margin-bottom: 16px;
  font-size: 0.95rem;
}

.category {
  background: #00b4d8;
  color: white;
  padding: 4px 14px;
  border-radius: 30px;
  font-size: 0.85rem;
}

.paper-card h3 {
  font-size: 1.45rem;
  line-height: 1.4;
  margin-bottom: 12px;
}

.authors {
  color: #555;
  font-size: 1rem;
  margin-bottom: 18px;
}

.abstract {
  color: #444;
  margin-bottom: 22px;
}

.read-more {
  color: #00b4d8;
  text-decoration: none;
  font-weight: 600;
}





/* =========================
   ABOUT RESEARCH SECTION
========================= */

.about-research {
  padding: 90px 0;
  background: #ffffff;
}

.narrow-container {
  max-width: 950px;
  margin: auto;
}

.section-heading {
  text-align: center;
  margin-bottom: 45px;
}

.section-label {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: #8b6f3d;
  margin-bottom: 10px;
}

.section-heading h2 {
  font-size: 42px;
  color: #111827;
  font-family: 'Playfair Display', serif;
}

.about-content p {
  font-size: 17px;
  line-height: 1.9;
  color: #374151;
  margin-bottom: 24px;
  text-align: justify;
}

.research-focus {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 18px;
  margin-top: 50px;
}

.focus-item {
  background: #f9fafb;
  border: 1px solid #e5e7eb;
  border-radius: 14px;
  padding: 20px;
  display: flex;
  align-items: center;
  gap: 14px;
  transition: 0.3s ease;
}

.focus-item:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 25px rgba(0,0,0,0.06);
}

.focus-item i {
  font-size: 20px;
  color: #8b6f3d;
}

.focus-item span {
  font-size: 15px;
  font-weight: 600;
  color: #1f2937;
}



/* =========================
   RESEARCHER SECTION
========================= */

.researcher-section {
  padding: 90px 0;
  background: #f8fafc;
}

.researcher-card {
  background: #ffffff;
  border-radius: 22px;
  overflow: hidden;
  display: grid;
  grid-template-columns: 320px 1fr;
  box-shadow: 0 15px 40px rgba(0,0,0,0.06);
}

.researcher-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.researcher-info {
  padding: 55px;
}

.researcher-label {
  display: inline-block;
  margin-bottom: 16px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: #8b6f3d;
}

.researcher-info h2 {
  font-size: 42px;
  margin-bottom: 25px;
  color: #111827;
  font-family: 'Playfair Display', serif;
}

.researcher-info p {
  font-size: 17px;
  line-height: 1.9;
  color: #374151;
  margin-bottom: 20px;
  text-align: justify;
}

@media(max-width: 900px){

  .researcher-card{
    grid-template-columns: 1fr;
  }

  .researcher-image{
    height: 380px;
  }

  .researcher-info{
    padding: 35px 25px;
  }

  .researcher-info h2{
    font-size: 32px;
  }

}






/* =========================
   TERMS SECTION
========================= */

.terms-section {
  padding: 90px 0;
  background: #ffffff;
}

.terms-box {
  margin-top: 40px;
  border-top: 1px solid #e5e7eb;
}

.term-item {
  padding: 28px 0;
  border-bottom: 1px solid #e5e7eb;
}

.term-item h3 {
  font-size: 22px;
  margin-bottom: 12px;
  color: #111827;
  font-family: 'Playfair Display', serif;
}

.term-item p {
  font-size: 16px;
  line-height: 1.8;
  color: #4b5563;
}




/* =========================
   SOCIAL CONNECT SECTION
========================= */

.social-connect-section {
  padding: 70px 0;
  background: #f8fafc;
  border-top: 1px solid #e5e7eb;
}

.social-connect-box {
  background: #ffffff;
  border-radius: 22px;
  padding: 50px;
  box-shadow: 0 12px 35px rgba(0,0,0,0.05);
  text-align: center;
}

.social-label {
  display: inline-block;
  margin-bottom: 14px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: #8b6f3d;
}

.social-content h2 {
  font-size: 38px;
  color: #111827;
  margin-bottom: 18px;
  font-family: 'Playfair Display', serif;
}

.social-content p {
  max-width: 760px;
  margin: auto;
  font-size: 17px;
  line-height: 1.9;
  color: #4b5563;
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
  margin-top: 35px;
}

.social-btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 15px 26px;
  border-radius: 14px;
  text-decoration: none;
  font-size: 15px;
  font-weight: 600;
  transition: 0.3s ease;
}

.social-btn i {
  font-size: 18px;
}

.facebook-btn {
  background: #1877f2;
  color: #ffffff;
}

.youtube-btn {
  background: #ff0000;
  color: #ffffff;
}

.social-btn:hover {
  transform: translateY(-4px);
  opacity: 0.92;
}

@media(max-width: 768px){

  .social-connect-box{
    padding: 35px 22px;
  }

  .social-content h2{
    font-size: 30px;
  }

  .social-content p{
    font-size: 16px;
  }

  .social-btn{
    width: 100%;
    justify-content: center;
  }

}






/* ==================== FOOTER ==================== */
.footer {
  background: #0f172a;
  color: #aaa;
  text-align: center;
  padding: 50px 20px;
  font-size: 0.95rem;
}


/* =========================
   MOBILE
========================= */

@media (max-width: 768px) {

  .header .container {
    flex-direction: column;
    gap: 18px;
    align-items: center;
    text-align: center;
  }

  .nav {
    width: 100%;
    justify-content: center;
    flex-wrap: wrap;
    gap: 18px;
    margin-top: 5px;
  }

  .nav a {
    font-size: 15px;
  }

  .logo h1 {
    font-size: 1.25rem;
    white-space: nowrap;
  }

  .hero h1 {
    font-size: 2.8rem;
  }

  .papers-grid {
    grid-template-columns: 1fr;
  }

}