/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Source Sans 3', -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  background-color: #f9fafb;
  color: #333;
}

button {
  cursor: pointer;
  user-select: none;
}

/* Hydrogen theme colors */
:root {
  --hydrogen-500: hsl(227, 72%, 56%);
  --hydrogen-600: hsl(227, 72%, 48%);
  --hydrogen-700: hsl(227, 72%, 40%);
  --hydrogen-300: hsl(227, 72%, 68%);
  --hydrogen-200: hsl(227, 72%, 80%);
}

/* Main container */
.container {
  min-height: 100vh;
  padding: 2rem 1rem;
}

.max-w-6xl {
  max-width: 72rem;
  margin: 0 auto;
}

/* Header */
.header {
  text-align: center;
  margin-bottom: 2rem;
}

.header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  color: #1f2937;
  margin-bottom: 1rem;
}

@media (min-width: 1024px) {
  .header h1 {
    font-size: 3rem;
  }
}

.header-divider {
  width: 6rem;
  height: 0.25rem;
  background-color: var(--hydrogen-500);
  margin: 0 auto;
  border-radius: 9999px;
}

/* Quadrant Grid */
.quadrant-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin-bottom: 2rem;
}

@media (min-width: 768px) {
  .quadrant-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
  }
}

.quadrant-button {
  min-height: 140px;
  padding: 1.5rem;
  border-radius: 1rem;
  font-size: 1.5rem;
  font-weight: 600;
  color: white;
  background-color: var(--hydrogen-500);
  border: none;
  transition: all 0.3s ease;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

@media (min-width: 768px) {
  .quadrant-button {
    min-height: 180px;
    font-size: 1.875rem;
  }
}

.quadrant-button:hover {
  background-color: var(--hydrogen-600);
  transform: scale(1.05);
}

.quadrant-button:active {
  transform: scale(0.95);
}

.quadrant-button.active {
  background-color: var(--hydrogen-700);
  box-shadow: 0 0 0 4px var(--hydrogen-300);
}

/* Navigation Pills */
.nav-pills {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 2rem;
}

.nav-pill {
  padding: 1rem 2rem;
  border-radius: 9999px;
  font-size: 1.125rem;
  font-weight: 500;
  color: white;
  background-color: var(--hydrogen-500);
  border: none;
  transition: all 0.3s ease;
}

.nav-pill:hover {
  background-color: var(--hydrogen-600);
  transform: scale(1.05);
}

.nav-pill.active {
  background-color: var(--hydrogen-700);
  box-shadow: 0 0 0 4px var(--hydrogen-300);
}

/* Instruction text */
.instruction-text {
  text-align: center;
  color: #6b7280;
  font-size: 1.125rem;
  margin-bottom: 2rem;
}

/* Content Card */
.content-card {
  background-color: white;
  border-radius: 1rem;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  padding: 2rem;
  margin-bottom: 2rem;
}

.content-card-header {
  border-bottom: 1px solid #e5e7eb;
  padding-bottom: 1rem;
  margin-bottom: 1.5rem;
}

.content-card-title {
  font-size: 1.875rem;
  font-weight: 700;
  color: #1f2937;
  margin-bottom: 0.5rem;
}

.content-card-divider {
  width: 4rem;
  height: 0.25rem;
  background-color: var(--hydrogen-500);
  border-radius: 9999px;
}

.content-card-body {
  color: #374151;
  font-size: 1.125rem;
  line-height: 1.75;
}

.content-card-body p {
  margin-bottom: 1rem;
  color: #6b7280;
}

.scroll-hint {
  text-align: center;
  font-weight: 700;
  font-style: italic;
  color: #374151;
}

/* Hidden utility */
.hidden {
  display: none !important;
}

/* Fade animations */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-fade-in {
  animation: fadeIn 0.5s ease-out;
}

/* Online Waterwash Styles */
.online-wrapper {
  font-family: 'Source Sans 3', -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Helvetica Neue", Arial, sans-serif;
  font-weight: 400;
  line-height: 1.6;
}

.online-progress-container {
  position: fixed;
  left: 0;
  top: 0;
  width: 280px;
  height: 100vh;
  background-color: #ffffff;
  padding: 80px 40px;
  z-index: 100;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

.online-progress-container.visible {
  opacity: 1;
  visibility: visible;
}

.online-timeline-nav ul {
  list-style: none;
  position: relative;
}

.online-timeline-nav ul::before {
  content: '';
  position: absolute;
  left: 11px;
  top: 24px;
  bottom: 24px;
  width: 2px;
  background-color: #e0e0e0;
}

.online-timeline-nav li {
  position: relative;
  margin-bottom: 48px;
}

.online-timeline-nav li:last-child {
  margin-bottom: 0;
}

.online-timeline-nav a {
  display: flex;
  align-items: center;
  text-decoration: none;
  color: #333;
  transition: color 0.3s ease;
  outline-offset: 4px;
}

.online-timeline-nav a:hover {
  color: #3A8DFF;
}

.online-timeline-nav a:focus-visible {
  outline: 2px solid #3A8DFF;
  border-radius: 4px;
}

.online-timeline-nav .circle {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background-color: #d0d0d0;
  border: 3px solid #ffffff;
  transition: background-color 0.3s ease, transform 0.3s ease;
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}

.online-timeline-nav a[aria-current="true"] .circle {
  background-color: #3A8DFF;
  transform: scale(1.2);
}

.online-timeline-nav .label {
  margin-left: 20px;
  font-weight: 600;
  font-size: 16px;
}

.online-timeline-nav a[aria-current="true"] .label {
  color: #3A8DFF;
}

.online-main-content {
  margin: 0 auto;
  padding: 80px 60px;
  max-width: 900px;
}

.online-main-title {
  font-size: 48px;
  font-weight: 700;
  color: #3A8DFF;
  margin-bottom: 60px;
  padding-bottom: 20px;
  border-bottom: 3px solid #3A8DFF;
  text-align: center;
}

.online-main-content section {
  min-height: 100vh;
  padding: 40px 0;
  scroll-margin-top: 20px;
}

.online-main-content section h2 {
  font-size: 32px;
  font-weight: 600;
  margin-bottom: 32px;
  color: #333;
  font-style: italic;
}

.online-main-content section p {
  font-size: 18px;
  margin-bottom: 24px;
  line-height: 1.8;
}

.online-main-content section ul {
  font-size: 18px;
  line-height: 1.8;
  margin-bottom: 24px;
  margin-left: 0;
  padding-left: 40px;
  list-style-type: disc;
  list-style-position: outside;
}

.online-main-content section li {
  margin-bottom: 12px;
  padding-left: 8px;
}

.online-main-content .graph-figure {
  margin: 40px 0 24px;
  text-align: center;
}

.online-main-content .graph-image {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  margin-bottom: 16px;
}

.online-main-content .graph-figure figcaption {
  font-size: 16px;
  line-height: 1.6;
  color: #333;
  font-style: italic;
  max-width: 700px;
  margin: 0 auto;
  padding: 0 20px;
}

.online-main-content .switcher-container {
  max-width: 42rem;
  margin: 40px auto 0;
  width: 100%;
}

.online-main-content .switcher-image-container {
  position: relative;
  width: 100%;
  background-color: #ffffff;
  border: 1px solid #e0e0e0;
  border-radius: 0.75rem;
  overflow: hidden;
  box-shadow: 0px 4px 6px -1px rgba(26, 26, 26, 0.08), 0px 2px 4px -1px rgba(26, 26, 26, 0.05);
}

.online-main-content .switcher-image-container img {
  width: 100%;
  height: auto;
  max-height: 500px;
  object-fit: contain;
  display: block;
  opacity: 1;
  transition: opacity 300ms ease-in-out;
}

.online-main-content .switcher-image-container img.fade-out {
  opacity: 0;
}

.online-main-content .switcher-caption {
  font-size: 16px;
  line-height: 1.6;
  color: #333;
  font-style: italic;
  text-align: center;
  margin: 20px auto 0;
  padding: 0 20px;
  max-width: 700px;
}

.online-main-content .switcher-button-group {
  display: flex;
  gap: 1rem;
  justify-content: center;
  margin-top: 1.5rem;
  flex-wrap: wrap;
}

.online-main-content .switcher-btn {
  min-width: 10rem;
  height: 3.5rem;
  padding: 0 1.5rem;
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.3px;
  border-radius: 0.5rem;
  border: 1px solid;
  cursor: pointer;
  transition: all 200ms ease;
  font-family: inherit;
}

.online-main-content .switcher-btn.active {
  background-color: #4169e1;
  color: #ffffff;
  border-color: #3759d1;
}

.online-main-content .switcher-btn.active:hover {
  background-color: #3759d1;
}

.online-main-content .switcher-btn.active:active {
  background-color: #2f4ec1;
}

.online-main-content .switcher-btn.inactive {
  background-color: transparent;
  color: #4169e1;
  border-color: #4169e1;
}

.online-main-content .switcher-btn.inactive:hover {
  background-color: rgba(65, 105, 225, 0.05);
}

.online-main-content .switcher-btn.inactive:active {
  background-color: rgba(65, 105, 225, 0.1);
}

.online-main-content .switcher-btn:focus-visible {
  outline: 2px solid #4169e1;
  outline-offset: 2px;
}

.online-back-to-top {
  position: fixed;
  bottom: 40px;
  right: 40px;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background-color: #3A8DFF;
  color: white;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease;
  z-index: 999;
  outline-offset: 4px;
}

.online-back-to-top:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.1);
}

.online-back-to-top:focus-visible {
  outline: 3px solid #333;
}

.online-back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

/* Offline Waterwash Styles */
.offline-wrapper {
  font-family: 'Source Sans 3', -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Helvetica Neue", Arial, sans-serif;
  font-weight: 400;
  line-height: 1.6;
}

.offline-progress-container {
  position: fixed;
  left: 0;
  top: 0;
  width: 280px;
  height: 100vh;
  background-color: #ffffff;
  padding: 80px 40px;
  z-index: 100;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

.offline-progress-container.visible {
  opacity: 1;
  visibility: visible;
}

.offline-timeline-nav ul {
  list-style: none;
  position: relative;
}

.offline-timeline-nav ul::before {
  content: '';
  position: absolute;
  left: 11px;
  top: 24px;
  bottom: 24px;
  width: 2px;
  background-color: #e0e0e0;
}

.offline-timeline-nav li {
  position: relative;
  margin-bottom: 48px;
}

.offline-timeline-nav li:last-child {
  margin-bottom: 0;
}

.offline-timeline-nav a {
  display: flex;
  align-items: center;
  text-decoration: none;
  color: #333;
  transition: color 0.3s ease;
  outline-offset: 4px;
}

.offline-timeline-nav a:hover {
  color: #3A8DFF;
}

.offline-timeline-nav a:focus-visible {
  outline: 2px solid #3A8DFF;
  border-radius: 4px;
}

.offline-timeline-nav .circle {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background-color: #d0d0d0;
  border: 3px solid #ffffff;
  transition: background-color 0.3s ease, transform 0.3s ease;
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}

.offline-timeline-nav a[aria-current="true"] .circle {
  background-color: #3A8DFF;
  transform: scale(1.2);
}

.offline-timeline-nav .label {
  margin-left: 20px;
  font-weight: 600;
  font-size: 16px;
}

.offline-timeline-nav a[aria-current="true"] .label {
  color: #3A8DFF;
}

.offline-main-content {
  margin: 0 auto;
  padding: 80px 60px;
  max-width: 900px;
}

.offline-main-title {
  font-size: 48px;
  font-weight: 700;
  color: #3A8DFF;
  margin-bottom: 60px;
  padding-bottom: 20px;
  border-bottom: 3px solid #3A8DFF;
  text-align: center;
}

.offline-main-content section {
  min-height: 100vh;
  padding: 40px 0;
  scroll-margin-top: 20px;
}

.offline-main-content section h2 {
  font-size: 32px;
  font-weight: 600;
  margin-bottom: 32px;
  color: #333;
  font-style: italic;
}

.offline-main-content section p {
  font-size: 18px;
  margin-bottom: 24px;
  line-height: 1.8;
}

.offline-main-content section ul {
  font-size: 18px;
  line-height: 1.8;
  margin-bottom: 24px;
  margin-left: 0;
  padding-left: 40px;
  list-style-type: disc;
  list-style-position: outside;
}

.offline-main-content section li {
  margin-bottom: 12px;
  padding-left: 8px;
}

.offline-main-content .image-switcher-container {
  max-width: 42rem;
  margin: 2rem auto 0;
  width: 100%;
}

.offline-main-content .image-container {
  position: relative;
  width: 100%;
  background-color: #ffffff;
  border: 1px solid #e0e0e0;
  border-radius: 0.75rem;
  overflow: hidden;
  box-shadow: 0px 4px 6px -1px rgba(26, 26, 26, 0.08), 0px 2px 4px -1px rgba(26, 26, 26, 0.05);
}

.offline-main-content .image-container img {
  width: 100%;
  height: auto;
  max-height: 500px;
  object-fit: contain;
  display: block;
  opacity: 1;
  transition: opacity 300ms ease-in-out;
}

.offline-main-content .image-container img.fade-out {
  opacity: 0;
}

.offline-main-content .caption {
  max-width: 42rem;
  margin: 1.5rem auto;
  padding: 0 1rem;
  color: #6b7280;
  font-size: 0.9375rem;
  line-height: 1.6;
  text-align: center;
  opacity: 1;
  transition: opacity 300ms ease-in-out;
  min-height: 3rem;
}

.offline-main-content .caption.fade-out {
  opacity: 0;
}

.offline-main-content .button-group {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

.offline-main-content .switcher-btn {
  min-width: 10rem;
  height: 3.5rem;
  padding: 0 1.5rem;
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  border-radius: 0.5rem;
  border: 1px solid;
  cursor: pointer;
  transition: all 200ms ease;
  font-family: 'Source Sans 3', sans-serif;
}

.offline-main-content .switcher-btn.active {
  background-color: #4169e1;
  color: #ffffff;
  border-color: #3759d1;
}

.offline-main-content .switcher-btn.active:hover {
  background-color: #3759d1;
}

.offline-main-content .switcher-btn.active:active {
  background-color: #2f4ec1;
}

.offline-main-content .switcher-btn.inactive {
  background-color: transparent;
  color: #4169e1;
  border-color: #4169e1;
}

.offline-main-content .switcher-btn.inactive:hover {
  background-color: rgba(65, 105, 225, 0.05);
}

.offline-main-content .switcher-btn.inactive:active {
  background-color: rgba(65, 105, 225, 0.1);
}

.offline-main-content .switcher-btn:focus-visible {
  outline: 2px solid #4169e1;
  outline-offset: 2px;
}

.offline-main-content .section-image {
  margin: 2rem auto;
  text-align: center;
}

.offline-main-content .section-image img {
  max-width: 100%;
  height: auto;
  border-radius: 0.75rem;
  box-shadow: 0px 4px 6px -1px rgba(26, 26, 26, 0.08), 0px 2px 4px -1px rgba(26, 26, 26, 0.05);
}

.offline-main-content .section-image figcaption {
  margin-top: 1rem;
  color: #6b7280;
  font-size: 0.9375rem;
  line-height: 1.6;
  font-style: italic;
}

.offline-back-to-top {
  position: fixed;
  bottom: 40px;
  right: 40px;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background-color: #3A8DFF;
  color: white;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease;
  z-index: 999;
  outline-offset: 4px;
}

.offline-back-to-top:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.1);
}

.offline-back-to-top:focus-visible {
  outline: 3px solid #333;
}

.offline-back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

/* Chemical Waterwash Styles */
.chemical-wrapper {
  font-family: 'Source Sans 3', -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Helvetica Neue", Arial, sans-serif;
  font-weight: 400;
  line-height: 1.6;
}

.chemical-progress-container {
  position: fixed;
  left: 0;
  top: 0;
  width: 280px;
  height: 100vh;
  background-color: #ffffff;
  padding: 80px 40px;
  z-index: 100;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

.chemical-progress-container.visible {
  opacity: 1;
  visibility: visible;
}

.chemical-timeline-nav ul {
  list-style: none;
  position: relative;
}

.chemical-timeline-nav ul::before {
  content: '';
  position: absolute;
  left: 11px;
  top: 24px;
  bottom: 24px;
  width: 2px;
  background-color: #e0e0e0;
}

.chemical-timeline-nav li {
  position: relative;
  margin-bottom: 48px;
}

.chemical-timeline-nav li:last-child {
  margin-bottom: 0;
}

.chemical-timeline-nav a {
  display: flex;
  align-items: center;
  text-decoration: none;
  color: #333;
  transition: color 0.3s ease;
  outline-offset: 4px;
}

.chemical-timeline-nav a:hover {
  color: #3A8DFF;
}

.chemical-timeline-nav a:focus-visible {
  outline: 2px solid #3A8DFF;
  border-radius: 4px;
}

.chemical-timeline-nav .circle {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background-color: #d0d0d0;
  border: 3px solid #ffffff;
  transition: background-color 0.3s ease, transform 0.3s ease;
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}

.chemical-timeline-nav a[aria-current="true"] .circle {
  background-color: #3A8DFF;
  transform: scale(1.2);
}

.chemical-timeline-nav .label {
  margin-left: 20px;
  font-weight: 600;
  font-size: 16px;
}

.chemical-timeline-nav a[aria-current="true"] .label {
  color: #3A8DFF;
}

.chemical-main-content {
  margin: 0 auto;
  padding: 80px 60px;
  max-width: 900px;
}

.chemical-main-title {
  font-size: 48px;
  font-weight: 700;
  color: #3A8DFF;
  margin-bottom: 60px;
  padding-bottom: 20px;
  border-bottom: 3px solid #3A8DFF;
  text-align: center;
}

.chemical-main-content section {
  min-height: auto;
  padding: 40px 0;
  scroll-margin-top: 20px;
  margin-bottom: 40px;
}

.chemical-main-content section h2 {
  font-size: 32px;
  font-weight: 600;
  margin-bottom: 32px;
  color: #333;
  font-style: italic;
}

.chemical-main-content section h3 {
  font-size: 22px;
  font-weight: 600;
  margin-top: 32px;
  margin-bottom: 16px;
  color: #333;
}

.chemical-main-content section p {
  font-size: 18px;
  margin-bottom: 24px;
  line-height: 1.8;
}

.chemical-main-content section ul {
  font-size: 18px;
  line-height: 1.8;
  margin-bottom: 24px;
  margin-left: 0;
  padding-left: 40px;
  list-style-type: disc;
  list-style-position: outside;
}

.chemical-main-content section li {
  margin-bottom: 12px;
  padding-left: 8px;
}

.chemical-main-content .surfactant-image {
  margin-top: 32px;
  margin-bottom: 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.chemical-main-content .surfactant-image img {
  width: 60%;
  max-width: 600px;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.chemical-main-content .image-caption {
  font-size: 16px;
  font-style: italic;
  color: #666;
  text-align: center;
  margin-top: 12px;
  line-height: 1.6;
}

.chemical-back-to-top {
  position: fixed;
  bottom: 40px;
  right: 40px;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background-color: #3A8DFF;
  color: white;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease;
  z-index: 999;
  outline-offset: 4px;
}

.chemical-back-to-top:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.1);
}

.chemical-back-to-top:focus-visible {
  outline: 3px solid #333;
}

.chemical-back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

/* Deionised Water Styles */
.deionised-water-wrapper {
  position: relative;
  font-family: 'Source Sans 3', -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Helvetica Neue", Arial, sans-serif;
  background-color: #ffffff;
}

#timeline-nav {
  position: fixed;
  left: 0;
  top: 0;
  width: 280px;
  height: 100vh;
  background-color: #ffffff;
  padding: 80px 40px;
  z-index: 100;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

#timeline-nav.visible {
  opacity: 1;
  visibility: visible;
}

#timeline-nav ul {
  list-style: none;
  position: relative;
}

#timeline-nav ul::before {
  content: '';
  position: absolute;
  left: 11px;
  top: 24px;
  bottom: 24px;
  width: 2px;
  background-color: #e0e0e0;
}

#timeline-nav li {
  position: relative;
  margin-bottom: 48px;
}

#timeline-nav li:last-child {
  margin-bottom: 0;
}

#timeline-nav a {
  display: flex;
  align-items: center;
  text-decoration: none;
  color: #333;
  transition: color 0.3s ease;
  outline-offset: 4px;
}

#timeline-nav a:hover {
  color: #3A8DFF;
}

#timeline-nav a:focus-visible {
  outline: 2px solid #3A8DFF;
  border-radius: 4px;
}

#timeline-nav .circle {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background-color: #d0d0d0;
  border: 3px solid #ffffff;
  transition: background-color 0.3s ease, transform 0.3s ease;
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}

#timeline-nav a[aria-current="true"] .circle {
  background-color: #3A8DFF;
  transform: scale(1.2);
}

#timeline-nav .label {
  margin-left: 20px;
  font-weight: 600;
  font-size: 16px;
}

#timeline-nav a[aria-current="true"] .label {
  color: #3A8DFF;
}

.deionised-main-content {
  margin: 0 auto;
  padding: 80px 60px;
  max-width: 900px;
}

.deionised-water-container {
  font-weight: 400;
  color: #333;
  line-height: 1.6;
}

.deionised-water-container .main-title {
  font-size: 48px;
  font-weight: 700;
  color: #3A8DFF;
  margin-bottom: 60px;
  padding-bottom: 20px;
  border-bottom: 3px solid #3A8DFF;
  text-align: center;
}

.deionised-water-container section {
  min-height: 100vh;
  padding: 20px 0;
  scroll-margin-top: 20px;
}

.deionised-water-container #process {
  padding: 20px 0 20px 0;
  min-height: auto;
}

.deionised-water-container #set-up {
  padding: 20px 0 20px 0;
  min-height: auto;
}

.deionised-water-container #time {
  padding-top: 0;
  margin-top: 0;
}

.deionised-water-container section h2 {
  font-size: 32px;
  font-weight: 600;
  margin-bottom: 32px;
  color: #333;
  font-style: italic;
}

.deionised-water-container section h3 {
  font-size: 22px;
  font-weight: 600;
  margin-top: 32px;
  margin-bottom: 16px;
  color: #333;
}

.deionised-water-container section p {
  font-size: 18px;
  margin-bottom: 24px;
  line-height: 1.8;
}

.deionised-water-container section ul {
  font-size: 18px;
  line-height: 1.8;
  margin-bottom: 24px;
  margin-left: 0;
  padding-left: 40px;
  list-style-type: disc;
  list-style-position: outside;
}

.deionised-water-container section li {
  margin-bottom: 12px;
  padding-left: 8px;
}

.deionised-water-container .intro-image {
  margin: 32px 0;
  text-align: center;
}

.deionised-water-container .intro-image img {
  width: 100%;
  max-width: 700px;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.deionised-water-container .intro-image figcaption {
  margin-top: 12px;
  font-size: 16px;
  font-style: italic;
  color: #666;
  line-height: 1.6;
}

.deionised-water-container .element-buttons {
  display: flex;
  gap: 16px;
  margin-top: 24px;
  margin-bottom: 40px;
  width: 100%;
}

.deionised-water-container .element-btn {
  flex: 1;
  padding: 20px 20px;
  font-size: 18px;
  font-weight: 600;
  color: white;
  background-color: #3A8DFF;
  border: 2px solid #3A8DFF;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
  font-family: 'Source Sans 3', sans-serif;
}

.deionised-water-container .element-btn:hover {
  background-color: #2c7ae6;
  border-color: #2c7ae6;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.deionised-water-container .element-btn:hover::after {
  content: attr(title);
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  margin-bottom: 8px;
  padding: 6px 12px;
  background-color: #333;
  color: white;
  font-size: 14px;
  font-weight: 400;
  border-radius: 4px;
  white-space: nowrap;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.deionised-water-container .element-btn:hover::before {
  content: '';
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  margin-bottom: 2px;
  border: 6px solid transparent;
  border-top-color: #333;
}

.deionised-water-container .element-btn:active {
  transform: translateY(0);
}

.deionised-water-container .test-buttons {
  margin-top: 24px;
  margin-bottom: 40px;
  width: 100%;
}

.deionised-water-container .test-button-row {
  display: flex;
  gap: 16px;
  margin-bottom: 16px;
}

.deionised-water-container .test-button-row:last-child {
  margin-bottom: 0;
}

.deionised-water-container .test-btn {
  flex: 1;
  padding: 20px 20px;
  font-size: 18px;
  font-weight: 600;
  color: white;
  background-color: #3A8DFF;
  border: 2px solid #3A8DFF;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
  font-family: 'Source Sans 3', sans-serif;
}

.deionised-water-container .test-button-row:last-child .test-btn {
  flex: 0 0 calc((100% - 32px) / 3);
}

.deionised-water-container .test-btn:hover {
  background-color: #2c7ae6;
  border-color: #2c7ae6;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.deionised-water-container .test-btn:active {
  transform: translateY(0);
}

.deionised-water-container .purification-system {
  display: flex;
  gap: 32px;
  margin-bottom: 48px;
  align-items: center;
}

.deionised-water-container .purification-system:last-child {
  margin-bottom: 0;
}

.deionised-water-container .system-text {
  flex: 1;
}

.deionised-water-container .system-text h3 {
  margin-top: 0;
  margin-bottom: 12px;
}

.deionised-water-container .system-text p {
  margin-bottom: 0;
}

.deionised-water-container .system-image {
  flex: 1;
}

.deionised-water-container .system-image img {
  width: 100%;
  height: 250px;
  object-fit: contain;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

/* Responsive Media Queries */
@media (max-width: 768px) {
  .header h1 {
    font-size: 2rem;
  }
  
  .deionised-water-container .purification-system {
    flex-direction: column;
  }
}