:root {
  --primary: #E07541;
  --secondary: #CD2249;
  --accent: #A42E60;
  --text: #231F20;
  --text-light: #666666;
  --background: #FFFFFF;
  --surface: #F5F5F5;
  --border: #E0E0E0;
  --success: #2E7D32;
  --error: #D32F2F;
  
  --font-zh: 'Noto Sans TC', 'PingFang TC', 'Microsoft JhengHei', sans-serif;
  --font-en: Arial, Helvetica, sans-serif;
  
  --shadow-sm: 0 2px 4px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
  
  --transition: all 0.3s ease;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  height: 100%;
  overflow-x: hidden;
}

body {
  font-family: var(--font-zh);
  background: var(--background);
  color: var(--text);
  line-height: 1.6;
}

#app {
  height: 100%;
  min-height: 100vh;
}

/* Page Transitions */
.page {
  display: none;
  min-height: 100vh;
}

.page.active {
  display: block;
}

/* Title Page */
#title-page {
  background: linear-gradient(135deg, #FFFFFF 0%, #FFF8F5 50%, #FFF0EB 100%);
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 20px;
}

#title-page.active {
  display: flex;
}

.title-content {
  max-width: 700px;
  text-align: center;
  animation: fadeInUp 0.8s ease forwards;
}

.cityu-logo {
  margin-bottom: 32px;
}

.cityu-logo img {
  height: 60px;
  width: auto;
}

.title-zh {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 8px;
  letter-spacing: 2px;
}

.title-en {
  font-size: 1.4rem;
  font-weight: 500;
  color: var(--text-light);
  margin-bottom: 24px;
  font-family: var(--font-en);
}

.divider {
  width: 80px;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  margin: 24px auto;
  border-radius: 2px;
}

.description-zh,
.description-en {
  font-size: 1rem;
  color: var(--text-light);
  line-height: 1.8;
  margin-bottom: 12px;
  font-family: var(--font-en);
}

.description-zh {
  font-family: var(--font-zh);
}

.start-hint {
  margin-top: 48px;
  animation: bounce 2s infinite;
  cursor: pointer;
  padding: 20px;
}

.start-btn {
  margin-top: 40px;
  padding: 16px 48px;
  font-size: 1.2rem;
  font-weight: 600;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: var(--radius-lg);
  cursor: pointer;
  font-family: var(--font-zh);
  transition: var(--transition);
}

.start-btn:hover {
  background: #c86436;
  transform: translateY(-2px);
}

.hint-zh,
.hint-en {
  display: block;
  font-size: 0.9rem;
  color: var(--primary);
  font-family: var(--font-en);
}

.hint-zh {
  font-family: var(--font-zh);
}

.scroll-icon {
  margin-top: 12px;
  color: var(--primary);
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes bounce {
  0%, 20%, 50%, 80%, 100% {
    transform: translateY(0);
  }
  40% {
    transform: translateY(10px);
  }
  60% {
    transform: translateY(5px);
  }
}

/* Language Page */
#language-page {
  background: var(--background);
  display: none;
  flex-direction: column;
  min-height: 100vh;
}

#language-page.active {
  display: flex;
}

#language-page .language-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.language-content {
  text-align: center;
  padding: 20px;
  width: 100%;
  max-width: 700px;
  margin: 0 auto;
}

.lang-title-zh,
.lang-title-en {
  font-size: 1.8rem;
  color: var(--text);
  margin-bottom: 40px;
  font-family: var(--font-en);
}

.lang-title-zh {
  font-family: var(--font-zh);
}

.language-buttons {
  display: flex;
  gap: 24px;
  justify-content: center;
  flex-wrap: wrap;
}

.lang-btn {
  min-width: 180px;
  padding: 24px 48px;
  font-size: 1.5rem;
  font-weight: 600;
  border: 3px solid var(--primary);
  background: transparent;
  color: var(--primary);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font-zh);
}

.lang-btn:hover {
  background: var(--primary);
  color: white;
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.lang-btn:active {
  transform: translateY(0);
}

/* Survey Page */
#survey-page {
  background: var(--surface);
  display: none;
  min-height: 100vh;
}

#survey-page.active {
  display: block;
}

.survey-container {
  max-width: 700px;
  margin: 0 auto;
  background: var(--background);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

@media (min-width: 768px) {
  .survey-container {
    min-height: auto;
    margin: 20px auto;
    min-height: calc(100vh - 40px);
  }
}

.survey-header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  padding: 20px 24px;
  color: white;
  flex-shrink: 0;
}

.progress-bar {
  height: 6px;
  background: rgba(255,255,255,0.3);
  border-radius: 3px;
  overflow: hidden;
  margin-bottom: 8px;
}

.progress-fill {
  height: 100%;
  background: white;
  border-radius: 3px;
  transition: width 0.4s ease;
  width: 0%;
}

.progress-text {
  font-size: 0.85rem;
  text-align: right;
  font-family: var(--font-en);
}

.survey-content {
  padding: 32px 24px;
  min-height: 300px;
  flex: 1;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

.section-title {
  font-size: 1.1rem;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 24px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--border);
  font-family: var(--font-zh);
}

.question-text {
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--text);
  margin-bottom: 24px;
  line-height: 1.5;
  font-family: var(--font-zh);
}

.question-text-en {
  font-family: var(--font-en);
  font-weight: 400;
  color: var(--text-light);
  margin-top: 8px;
  font-size: 1rem;
}

/* Form Elements */
.options-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.option-item {
  display: flex;
  align-items: center;
  padding: 16px 20px;
  border: 2px solid var(--border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition);
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}

.option-item:hover {
  border-color: var(--primary);
  background: #FFF8F5;
}

.option-item.selected {
  border-color: var(--primary);
  background: #FFF8F5;
}

.option-item input {
  display: none;
}

.option-radio,
.option-checkbox {
  width: 22px;
  height: 22px;
  border: 2px solid var(--border);
  border-radius: 50%;
  margin-right: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: var(--transition);
}

.option-checkbox {
  border-radius: var(--radius-sm);
}

.option-item.selected .option-radio,
.option-item.selected .option-checkbox {
  border-color: var(--primary);
  background: var(--primary);
}

.option-item.selected .option-radio::after {
  content: '';
  width: 10px;
  height: 10px;
  background: white;
  border-radius: 50%;
}

.option-item.selected .option-checkbox::after {
  content: '✓';
  color: white;
  font-size: 14px;
  font-weight: bold;
}

.option-text {
  font-size: 1rem;
  color: var(--text);
  font-family: var(--font-zh);
}

.option-text-en {
  font-family: var(--font-en);
  color: var(--text-light);
  font-size: 0.9rem;
}

/* Scale Questions */
.scale-container {
  padding: 16px 0;
}

.scale-options {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 12px;
}

.scale-option {
  flex: 1;
  text-align: center;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.scale-label {
  display: block;
  padding: 16px 8px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
  font-size: 1.1rem;
  font-weight: 500;
  user-select: none;
}

.scale-option:active .scale-label {
  transform: scale(0.95);
}

.scale-option input:checked + .scale-label {
  border-color: var(--primary);
  background: var(--primary);
  color: white;
}

.scale-labels {
  display: none;
}

/* Slider Styles */
.scale-labels-top {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text);
  font-weight: 500;
  margin-bottom: 16px;
  font-family: var(--font-zh);
}

.scale-slider {
  width: 100%;
  height: 8px;
  border-radius: 4px;
  background: linear-gradient(to right, var(--primary) 0%, var(--primary) var(--slider-progress, 0%), var(--border) var(--slider-progress, 0%), var(--border) 100%);
  outline: none;
  -webkit-appearance: none;
  margin: 30px 0 10px;
}

.scale-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(224, 117, 65, 0.4);
  transition: transform 0.2s;
}

.scale-slider::-webkit-slider-thumb:hover {
  transform: scale(1.1);
}

.scale-slider::-moz-range-thumb {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  border: none;
  box-shadow: 0 2px 8px rgba(224, 117, 65, 0.4);
}

.scale-value {
  display: none;
  text-align: center;
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary);
  margin: 10px 0;
}

.scale-numbers {
  display: flex;
  justify-content: space-between;
  padding: 0 8px;
  margin-top: 8px;
}

.scale-number {
  width: 36px;
  text-align: center;
  font-size: 1.1rem;
  font-weight: 700;
  color: #666;
  opacity: 0.4;
  transition: all 0.2s;
}

.scale-number.active {
  opacity: 1;
  color: var(--primary);
  transform: scale(1.2);
}

/* Text Input */
.text-input {
  width: 100%;
  padding: 16px;
  border: 2px solid var(--border);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-family: var(--font-zh);
  resize: vertical;
  min-height: 120px;
  transition: var(--transition);
}

.text-input:focus {
  outline: none;
  border-color: var(--primary);
}

.text-input::placeholder {
  color: var(--text-light);
}

/* Navigation */
.survey-navigation {
  display: flex;
  justify-content: space-between;
  padding: 20px 24px;
  border-top: 1px solid var(--border);
  background: var(--surface);
  position: sticky;
  bottom: 0;
  z-index: 100;
}

.nav-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  min-width: 120px;
  border: none;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font-zh);
  touch-action: manipulation;
}

.nav-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.nav-btn:active {
  transform: translateY(0);
}

.nav-prev {
  background: var(--surface);
  color: var(--text);
  border: 2px solid var(--border);
}

.nav-prev:hover:not(:disabled) {
  border-color: var(--text-light);
}

.nav-prev:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.nav-next {
  background: var(--primary);
  color: white;
}

.nav-next:hover {
  background: #c86436;
}

.next-text,
.prev-text {
  font-family: var(--font-zh);
}

/* End Page */
#end-page {
  background: linear-gradient(135deg, #FFFFFF 0%, #FFF8F5 50%, #FFF0EB 100%);
  display: none;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
}

#end-page.active {
  display: flex;
}

.end-content {
  text-align: center;
  padding: 40px;
}

.success-icon {
  color: var(--success);
  margin-bottom: 24px;
  animation: scaleIn 0.5s ease forwards;
}

@keyframes scaleIn {
  from {
    transform: scale(0);
    opacity: 0;
  }
  to {
    transform: scale(1);
    opacity: 1;
  }
}

.end-title-zh,
.end-title-en {
  font-size: 2rem;
  color: var(--primary);
  margin-bottom: 16px;
  font-family: var(--font-zh);
}

.end-title-en {
  font-family: var(--font-en);
  font-size: 1.5rem;
  color: var(--text-light);
}

.end-message-zh,
.end-message-en {
  font-size: 1.1rem;
  color: var(--text-light);
  max-width: 500px;
  font-family: var(--font-en);
}

.end-message-zh {
  font-family: var(--font-zh);
}

/* Loading Overlay */
.loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(255,255,255,0.95);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

.loading-overlay.active {
  opacity: 1;
  visibility: visible;
}

.spinner {
  width: 50px;
  height: 50px;
  border: 4px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.loading-text-zh,
.loading-text-en {
  margin-top: 16px;
  font-size: 1rem;
  color: var(--text);
  font-family: var(--font-zh);
}

.loading-text-en {
  font-family: var(--font-en);
}

/* Toasts */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  padding: 16px 24px;
  border-radius: var(--radius-md);
  color: white;
  font-size: 1rem;
  z-index: 1001;
  opacity: 0;
  transition: var(--transition);
  font-family: var(--font-zh);
}

.toast.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

.error-toast {
  background: var(--error);
}

.success-toast {
  background: var(--success);
}

/* Responsive */
@media (max-width: 768px) {
  .title-zh {
    font-size: 1.8rem;
  }
  
  .title-en {
    font-size: 1.1rem;
  }
  
  .lang-btn {
    min-width: 140px;
    padding: 20px 32px;
    font-size: 1.2rem;
  }
  
  .survey-content {
    padding: 24px 16px;
  }
  
  .question-text {
    font-size: 1.1rem;
  }
  
  .scale-options {
    flex-wrap: wrap;
  }
  
  .scale-option {
    flex: 0 0 calc(33.333% - 6px);
  }
  
  .nav-btn {
    padding: 10px 16px;
    font-size: 0.9rem;
  }
}

@media (max-width: 480px) {
  .scale-option {
    flex: 0 0 calc(50% - 4px);
  }
  
  .scale-option:nth-child(5) {
    flex: 0 0 100%;
  }
}

/* Hidden elements for language switching - Title page shows both */
#title-page .title-en,
#title-page .title-zh,
#title-page .description-en,
#title-page .description-zh {
  display: block !important;
}

/* Hide English elements when Chinese is selected */
html[lang="zh"] .title-en,
html[lang="zh"] .description-en,
html[lang="zh"] .hint-en,
html[lang="zh"] .lang-title-en,
html[lang="zh"] .lang-text[data-lang-en],
html[lang="zh"] .loading_text_en,
html[lang="zh"] .end_message_en,
html[lang="zh"] .question-text-en,
html[lang="zh"] .option-text-en,
html[lang="zh"] .scale-labels,
html[lang="zh"] .progress-text {
  display: none;
}

html[lang="en"] .title-zh,
html[lang="en"] .description-zh,
html[lang="en"] .hint-zh,
html[lang="en"] .lang-title-zh,
html[lang="en"] .lang-text[data-lang-zh],
html[lang="en"] .loading-text-zh,
html[lang="en"] .end-message-zh,
html[lang="en"] .end-title-zh {
  display: none;
}

/* Navigation text is now handled by HTML content */