/* body*/
body {
  background: linear-gradient(135deg, #ffffff 0%, #e8f1ff 50%, #f5fcff 100%);
  color: #1a252f;
  font-family: "Montserrat", sans-serif;
}
section .container {
  background: rgba(250, 252, 255, 0.75);
  box-shadow: 0 16px 56px -12px rgba(0, 0, 0, 0.14);
}

a {
  color: #2c3e50;
  text-decoration: none;
}
a:hover {
  color: #3498db;
}

/* navbar */
.navbar .nav-link {
  transition: color 0.25s ease, opacity 0.25s ease;
  opacity: 0.8;
}
.navbar .nav-link:hover {
  opacity: 1;
  color: #2c3e50;
}

/* card */
.card {
  background-color: #ffffff;
  border: 1px solid #e1e6ea;
  border-radius: 16px;
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}
.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 25px rgba(0, 0, 0, 0.08);
}

.card-text {
  color: #5d6d7e;
}

/* carousel */
.carousel-item img {
  border-radius: 16px;
  transition: transform 0.5s ease, box-shadow 0.5s ease, border-color 0.5s ease;
}
.carousel-item img:hover {
  transform: translateY(-12px);
  box-shadow: 0 20px 35px rgba(0, 0, 0, 0.12);
  cursor: pointer;
}

/* button */
.btn {
  background: linear-gradient(135deg, rgba(0, 122, 255, 0.2), rgba(90, 200, 250, 0.15));
  box-shadow: 0 4px 24px rgba(0, 122, 255, 0.2), inset 0 1px 0 rgba(255, 255, 255, 0.4);
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
.btn:hover {
  background: linear-gradient(135deg, rgba(0, 122, 255, 0.25), rgba(90, 200, 250, 0.2));
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(0, 122, 255, 0.3), inset 0 1px 0 rgba(255, 255, 255, 0.5);
}

/* accordion */
.accordion-button.collapsed {
  border: 1px solid #000000;
  transition: background-color 0.3s ease, color 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
}
.accordion-button.collapsed:hover {
  background: linear-gradient(135deg, rgba(0, 122, 255, 0.2), rgba(90, 200, 250, 0.15));
  transform: translateY(-2px);
}
.accordion-item:has(.accordion-button:not(.collapsed)) {
  border: 2px solid #000000;
  box-shadow: 5px 5px #000000;
}
.accordion-collapse {
  overflow: hidden;
  transition: height 0.5s ease, transform 0.5s ease, opacity 0.5s ease;
  transform: translateY(-5px);
  opacity: 0;
}
.accordion-collapse.show {
  transform: translateY(0);
  opacity: 1;
}

/* filter tab */
#portfolio-filters .nav-link {
  border: 1px solid #e1e6ea;
  color: #1a252f;
}
#portfolio-filters .nav-link.active {
  background-color: #2c3e50;
  color: #ffffff;
}

/* footer */
footer .d-flex a:hover {
  transform: translateY(-2px);
}
footer .list-unstyled a {
  opacity: 0.5;
  transition: opacity 0.25s ease, transform 0.25s ease, padding-left 0.25s ease;
}
footer .list-unstyled a:hover {
  opacity: 1;
  transform: translateX(4px);
  padding-left: 4px;
}