/* Animation Utility Classes */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 600ms ease, transform 600ms ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

.slide-in {
  opacity: 0;
  transform: translateX(40px);
  transition: opacity 600ms ease, transform 600ms ease;
}

.slide-in.visible {
  opacity: 1;
  transform: translateX(0);
}

/* Staggered Animation Delays */
.fade-in:nth-child(1),
.slide-in:nth-child(1) {
  transition-delay: 0ms;
}

.fade-in:nth-child(2),
.slide-in:nth-child(2) {
  transition-delay: 100ms;
}

.fade-in:nth-child(3),
.slide-in:nth-child(3) {
  transition-delay: 200ms;
}

.fade-in:nth-child(4),
.slide-in:nth-child(4) {
  transition-delay: 300ms;
}

.fade-in:nth-child(5),
.slide-in:nth-child(5) {
  transition-delay: 400ms;
}

/* Hover Animations */
.project-card {
  transition: transform 300ms ease, box-shadow 300ms ease;
}

.nav-link {
  position: relative;
  overflow: hidden;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background-color: var(--color-primary-500);
  transition: width 300ms ease;
  transform: translateX(-50%);
}

.nav-link:hover::after {
  width: 80%;
}

/* Button Animations */
.button {
  position: relative;
  overflow: hidden;
  z-index: 1;
}

.button::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(255, 255, 255, 0.1);
  transform: translateX(-100%);
  transition: transform 300ms ease;
  z-index: -1;
}

.button:hover::before {
  transform: translateX(0);
}

/* Theme Toggle Animation */
.theme-toggle-icon {
  transition: transform 500ms ease;
}

.theme-toggle:hover .theme-toggle-icon {
  transform: rotate(180deg);
}

/* Logo Animation */
.logo {
  transition: transform 300ms ease, box-shadow 300ms ease;
}

.logo:hover {
  transform: scale(1.05);
  box-shadow: 0 0 0 4px rgba(var(--color-primary-500), 0.2);
}

/* Mobile Menu Animation */
.mobile-menu-icon,
.mobile-menu-icon::before,
.mobile-menu-icon::after {
  transition: transform 300ms ease, background-color 300ms ease;
}

/* Form Elements Animation */
.form-group input,
.form-group textarea {
  transition: border-color 300ms ease, box-shadow 300ms ease;
}

.form-group input:focus,
.form-group textarea:focus {
  box-shadow: 0 0 0 3px rgba(var(--color-primary-500), 0.2);
}

/* Loader Animation (for button click feedback) */
@keyframes spinner {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

.button.loading {
  position: relative;
  color: transparent;
}

.button.loading::after {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  top: 50%;
  left: 50%;
  margin-top: -8px;
  margin-left: -8px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top-color: white;
  animation: spinner 0.6s linear infinite;
}

/* Timeline markers pulsing effect */
@keyframes pulse {
  0% {
    box-shadow: 0 0 0 0 rgba(var(--color-primary-500), 0.4);
  }
  70% {
    box-shadow: 0 0 0 8px rgba(var(--color-primary-500), 0);
  }
  100% {
    box-shadow: 0 0 0 0 rgba(var(--color-primary-500), 0);
  }
}

.timeline-marker {
  animation: pulse 2s infinite;
}

/* Skill item hover animation */
.skill-item {
  transition: transform 200ms ease, padding-left 200ms ease, color 200ms ease;
}

.skill-item:hover {
  transform: translateX(5px);
  padding-left: 8px;
  color: var(--color-primary-500);
}

/* Header scroll animation */
.header.scrolled {
  background-color: var(--bg-primary);
  box-shadow: var(--shadow-md);
}

/* Page Transition Animation */
@keyframes fadeIn {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}

body {
  animation: fadeIn 600ms ease-in;
}