:root {
  --body-bg-color: #f8fafc;
  --body-text-color: #ffffff;
  --heading-color: #ffffff;
  --hero-gradient1: #168295;
  --hero-gradient2: #0b5e3a;
  --footer-bg-color: #21322a;
  --link-color: #2bb174;
  --header-bg-color: #ffffff;
  --font-family: "Times New Roman", Times, serif;
  --nav-link-color: #141414;
  --footer-text-color: #ffffff;
  --header-text-color: #ffffffff;
}
html {
  overflow-x: hidden;
}
body {
  background-color: var(--body-bg-color);
  color: var(--body-text-color) !important;
  font-family: var(--font-family);
  /* line-height: 1.5; */
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-size: 1.1rem;
  background-image:
    linear-gradient(rgba(0, 0, 0, 0.677), rgba(0, 0, 0, 0.662)),
    url("/images/body-bg.jpg");
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  background-attachment: fixed;
}

h1 {
  font-size: clamp(2rem, 4vw, 2.5rem) !important;
}
h2 {
  font-size: clamp(1.6rem, 3vw, 2rem) !important;
}
h3 {
  font-size: clamp(1.4rem, 3vw, 1.7rem) !important;
}
p {
  margin-bottom: 0.5rem !important;
}

section {
  padding: 15px 0;
  scroll-margin-top: 70px;
}

h2,
h3 {
  color: var(--heading-color) !important;
}

.content-area a {
  color: var(--link-color) !important;
  text-decoration: none !important;
}

.content-area a:hover {
  color: var(--link-color) !important;
  opacity: 0.8;
}
.links {
width: 279px;
margin-bottom: 15px;
}

.links h2 {
  font-family: "Cambria", "Times New Roman", Georgia, serif;
  font-size: 1.4rem;
  font-weight: 600;
  color: #ffffff;
  margin-bottom: 0.8rem;
  letter-spacing: 0.4px;
}

.sidebar-page-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.sidebar-page-list li {
  position: relative;
  padding-left: 1.2rem;
  margin-bottom: 0.5rem;
}

/* Mathematical-style marker */
.sidebar-page-list li::before {
  content: "•";
  position: absolute;
  left: 0;
  top: 0.15rem;
  font-size: 1.1rem;
  color: rgba(255, 255, 255, 0.6);
}

.sidebar-page-list a {
  display: block;
  padding: 0.45rem 0.6rem;
  font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  font-size: 0.95rem;
  color: rgba(255, 255, 255, 0.9);
  text-decoration: none;
  border-left: 3px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.sidebar-page-list a:hover {
  color: #ffffff;
  border-left-color: rgba(255, 255, 255, 0.6);
}

.twitter-tweet {
  width: 279px !important;
}

.x {
  display: flex;
  justify-content: center;
}
.error_page {
  min-height: 70vh;
}

.footer {
  background: var(--footer-bg-color);
  color: var(--footer-text-color);
  border-top: 1px solid var(--link-color);
}
.footer a {
  text-decoration: none;
  color: var(--footer-text-color) !important;
}
.footer-title {
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 1rem;
  position: relative;
  color: var(--footer-text-color) !important;
}
.footer-links {
  list-style: none;
  padding: 0;
  margin: 0;
}
.footer-links li {
  margin-bottom: 0.6rem;
}
.footer-links a {
  text-decoration: none;
  transition: all 0.3s ease;
}
.footer-links a:hover {
  padding-left: 6px;
}
.newsletter-form {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  margin-top: 1rem;
}
.newsletter-form input {
  flex: 1;
  padding: 0.6rem 0.9rem;
  border-radius: 8px;
  border: 0;
  outline: 0;
  background: color-mix(in srgb, var(--footer-bg-color) 80%, white 20%);
  color: var(--footer-text-color);
}
.newsletter-form input::placeholder {
  color: var(--footer-text-color);
}
.newsletter-form button {
  padding: 0.6rem 1.1rem;
  border-radius: 8px;
  border: 0;
  font-weight: 600;
  background: var(--link-color);
  color: var(--footer-text-color);
  transition: all 0.3s ease;
}
.newsletter-form button:hover {
  background: color-mix(in srgb, var(--link-color) 80%, white 20%);
}
.footer-divider {
  margin: 1.5rem 0;
  border-color: var(--link-color);
}
.social-icons {
  display: flex;
  gap: 0.75rem;
  margin-top: 17px;
}
.social-icons span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  color: var(--footer-text-color);
  background-color: color-mix(in srgb, var(--footer-bg-color), white 20%);
  font-size: 1.2rem;
  text-decoration: none;
  transition:
    background-color 0.25s ease,
    transform 0.25s ease;
}
.social-icons span:hover {
  background: linear-gradient(
    135deg,
    var(--link-color),
    var(--footer-text-color)
  );
  transform: translateY(-2px);
}
.footer img {
  filter: brightness(0) invert(1);
}

.navbar {
  background-color: var(--header-bg-color) !important;
  position: sticky;
  top: 0;
  z-index: 1020;
}

.hero-section {
  padding: 115px 0 25px 0;
  position: relative;
  overflow: hidden;
  color: var(--header-text-color);
}
.hero-section.gradient-bg {
  background: linear-gradient(
    135deg,
    var(--hero-gradient1),
    var(--hero-gradient2)
  );
}

.hero-section .container {
  position: relative;
  z-index: 2;
}

.navbar-light .navbar-nav .nav-link {
  color: var(--nav-link-color, #141414) !important;
}

.navbar-light .navbar-nav .nav-link.active {
  color: var(--link-color) !important;
  font-weight: bold;
}
/* Mobile nav */
@media (max-width: 1199.98px) {
  .navbar-collapse {
    position: fixed;
    top: 61px;
    left: 15px;
    right: 15px;
    background-color: color-mix(
      in srgb,
      var(--header-bg-color) 65%,
      transparent
    );
    backdrop-filter: blur(12px);
    border-radius: 12px;
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
    z-index: 9999;
    padding: 15px;
    margin: 0;
  }

  .navbar-nav {
    width: 100%;
  }

  .navbar-nav .nav-item {
    margin: 7px 0;
  }

  .navbar-nav .nav-item:hover {
    transform: translateY(-1px);
  }

  .navbar-nav .nav-link {
    font-size: 1.2rem;
    font-weight: 500;
    text-decoration: none;
    display: block;
    padding: 0;
  }

  .navbar-toggler {
    z-index: 10000;
    position: relative;
    border: var(--bs-border-width) solid var(--nav-link-color, #141414) !important;
  }
}

.custom-dropdown {
  border: 0;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.15);
  border-radius: 12px;
  padding: 0.5rem 0;
  margin-top: 0.5rem;
  min-width: 220px;
  background: color-mix(
    in srgb,
    var(--header-bg-color) 65%,
    transparent
  ) !important;
  backdrop-filter: blur(12px);
}

.custom-dropdown .dropdown-item {
  padding: 0.75rem 1.5rem;
  transition: all 0.3s ease;
  color: var(--nav-link-color, #141414) !important;
  font-weight: 500;
  border-radius: 0;
  text-wrap: wrap;
}
.dropdown-menu {
  display: none;
}

.custom-dropdown .dropdown-item:hover {
  color: #fff;
  background: color-mix(
    in srgb,
    var(--header-bg-color) 95%,
    transparent
  ) !important;
}

.nav-item.dropdown > .nav-link {
  display: flex;
  align-items: center;
}

.nav-item.dropdown > .nav-link .arrow {
  position: relative;
  margin-left: auto;
  border: solid var(--nav-link-color, #141414);
  border-width: 0 2px 2px 0;
  padding: 3px;
  transform: rotate(45deg);
  transition: transform 0.25s;
}
.dropdown.open .dropdown-menu {
  display: block;
}

@media (min-width: 1200px) {
  .nav-item.dropdown {
    position: relative;
  }
  .nav-item.dropdown > .nav-link .arrow {
    margin-left: 7px;
  }
  .custom-dropdown.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    margin-top: 0;
    z-index: 1000;
  }

  .nav-item.dropdown:hover > .nav-link .arrow {
    transform: rotate(-135deg);
  }
  .nav-item.dropdown:hover > .dropdown-menu {
    display: block !important;
  }
}
@media (max-width: 1199px) {
  .nav-item.dropdown > .nav-link .arrow {
    padding: 4px;
  }
}

.floating-rounded-navbar {
  background-color: var(--header-bg-color) !important;
  position: fixed !important;
  top: 15px !important;
  left: 7px !important;
  right: 7px !important;
  width: calc(100% - 11px) !important;
  z-index: 2000;
  border-radius: 21px;
  transition: all 0.3s ease;
}

@media (max-width: 1199.98px) {
  .floating-rounded-navbar .navbar-collapse {
    top: 85px !important;
  }
}

.navbar-brand {
  margin-right: 0 !important;
}
.heading {
  margin-bottom: 21px;
}

.heading h2 {
  font-family: "Times New Roman", "Cambria", "Georgia", serif;
  font-weight: 600;
  letter-spacing: 0.5px;
  margin-bottom: 1rem;
}

.heading p {
  font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  font-size: 1.05rem;
  line-height: 1.7;
  margin: 0.5rem auto;
}

/* Optional subtle academic refinement */
.heading p:not(:last-child) {
  margin-bottom: 0.75rem;
}
.box {
  padding: 1.8rem 21px;
  background: rgba(255, 255, 255, 0.04);
  border-left: 3px solid rgba(255, 255, 255, 0.25);
  height: 100%;
}

.box h3 {
  font-family: "Cambria", "Times New Roman", Georgia, serif;
  font-size: 1.4rem;
  font-weight: 600;
  color: #ffffff;
  margin-bottom: 0.8rem;
  letter-spacing: 0.4px;
}

.box p {
  font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  font-size: 1rem;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: 0.7rem;
}

.box p:last-child {
  margin-bottom: 0;
}
.cust-bg {
  padding: 1.5rem 21px;
  background: rgba(255, 255, 255, 0.035);
}

.cust-bg h2 {
  font-family: "Cambria", "Times New Roman", Georgia, serif;
  font-size: 2rem;
  font-weight: 600;
  color: #ffffff;
  letter-spacing: 0.5px;
}

.cust-bg h3 {
  font-family: "Cambria", "Times New Roman", Georgia, serif;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.95);
  margin-top: 1.8rem;
  margin-bottom: 0.6rem;
  letter-spacing: 0.3px;
}

.cust-bg p {
  font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  line-height: 1.75;
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: 0.9rem;
}

/* Subtle academic separation for sections */
.cust-bg h3::before {
  content: "∎ ";
  color: rgba(255, 255, 255, 0.6);
}
.white-img {
  filter: brightness(0) invert(1);
}
.colored-bg {
  padding: 1.5rem 19px;
  background: linear-gradient(
    135deg,
    rgba(20, 90, 70, 0.85),
    rgba(15, 60, 85, 0.85)
  );
  border-left: 4px solid rgba(255, 255, 255, 0.35);
}

.colored-bg h2 {
  font-family: "Cambria", "Times New Roman", Georgia, serif;
  font-size: 2rem;
  font-weight: 600;
  color: #ffffff;
  margin-bottom: 1rem;
  letter-spacing: 0.4px;
}

.colored-bg p {
  font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  font-size: 1rem;
  line-height: 1.75;
  color: rgba(255, 255, 255, 0.92);
  margin-bottom: 0.9rem;
}

.colored-bg p:last-child {
  margin-bottom: 0;
}