:root {
  --surface-0: #F5F7FA;
  --surface-1: #FFFFFF;
  --surface-2: #F0F4F8;
  --surface-3: #E8EEF5;
  --surface-4: #D1DBE8;
  --accent: #006EFF;
  --accent-hover: #0052CC;
  --accent-light: #E6F2FF;
  --accent-lighter: #F0F8FF;
  --accent-shadow: rgba(0, 110, 255, 0.15);
  --text-primary: #222222;
  --text-secondary: #5C5C5C;
  --text-muted: #999999;
  --text-link: #006EFF;
  --border: #DCDFE6;
  --border-light: #E4E7ED;
  --success: #00A870;
  --success-light: #E8F8F2;
  --warning: #FF9C00;
  --warning-light: #FFF3E0;
  --error: #ED4014;
  --error-light: #FFEBE8;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-full: 999px;
  --spacing-xs: clamp(0.5rem, 1vw, 0.75rem);
  --spacing-sm: clamp(0.75rem, 1.5vw, 1rem);
  --spacing-md: clamp(1rem, 2vw, 1.5rem);
  --spacing-lg: clamp(1.5rem, 3vw, 2rem);
  --spacing-xl: clamp(2rem, 4vw, 3rem);
  --font-display: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", "Microsoft YaHei", sans-serif;
  --font-body: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", "Microsoft YaHei", sans-serif;
  --shadow-sm: 0 2px 4px 0 rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 16px 0 rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 32px 0 rgba(0, 0, 0, 0.1);
  --shadow-accent: 0 4px 16px rgba(0, 110, 255, 0.25);
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  font-family: var(--font-body);
  background: #F5F7FA;
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  padding-bottom: 5rem;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.header {
  background: var(--surface-1);
  padding: var(--spacing-xl) var(--spacing-md);
  text-align: center;
  border-bottom: 1px solid var(--border-light);
  box-shadow: 0 2px 8px 0 rgba(0, 0, 0, 0.04);
}

.logo {
  max-width: clamp(200px, 40vw, 400px);
  height: auto;
  border-radius: var(--radius-md);
}

.logo-text {
  font-family: var(--font-display);
  font-size: clamp(1.875rem, 5vw, 2.75rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

.notice {
  background: var(--accent-lighter);
  margin: var(--spacing-lg) var(--spacing-md);
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: var(--radius-md);
  display: flex;
  gap: var(--spacing-sm);
  align-items: flex-start;
  border: 1px solid var(--accent-light);
  box-shadow: none;
}

.notice-icon {
  width: clamp(20px, 5vw, 24px);
  height: clamp(20px, 5vw, 24px);
  color: var(--accent);
  flex-shrink: 0;
  margin-top: 2px;
}

.notice-text {
  color: var(--text-secondary);
  font-size: clamp(0.875rem, 2vw, 0.9375rem);
  line-height: 1.7;
}

.recharge-section, .payment-section {
  max-width: 800px;
  margin: var(--spacing-xl) auto;
  padding: 0 var(--spacing-md);
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.125rem, 3vw, 1.375rem);
  font-weight: 600;
  margin-bottom: var(--spacing-lg);
  letter-spacing: -0.01em;
  color: var(--text-primary);
}

.amount-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: var(--spacing-md);
}

@media (max-width: 640px) {
  .amount-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
  }
}

.amount-item {
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg) var(--spacing-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-body);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.amount-item::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--accent-lighter);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.amount-item:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.amount-item:hover::before {
  opacity: 1;
}

.amount-item.active {
  background: var(--accent-lighter);
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent-shadow);
}

.amount-value {
  display: block;
  font-size: clamp(1.5rem, 4.5vw, 2rem);
  font-weight: 700;
  color: var(--accent);
  position: relative;
  z-index: 1;
}

.payment-methods {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-md);
}

@media (max-width: 640px) {
  .payment-methods {
    grid-template-columns: 1fr;
  }
}

.payment-btn {
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  font-family: var(--font-body);
  color: var(--text-primary);
  font-size: clamp(1rem, 2.5vw, 1.125rem);
  font-weight: 500;
  position: relative;
  overflow: hidden;
}

.payment-btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--accent-lighter);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.payment-btn:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.payment-btn:hover::before {
  opacity: 1;
}

.payment-btn:hover .payment-icon {
  transform: scale(1.05);
}

.payment-icon {
  width: clamp(32px, 7vw, 40px);
  height: clamp(32px, 7vw, 40px);
  color: var(--accent);
  transition: transform 0.25s ease;
  position: relative;
  z-index: 1;
}

.payment-btn span {
  position: relative;
  z-index: 1;
}

.customer-service-trigger {
  position: fixed;
  bottom: var(--spacing-xl);
  right: var(--spacing-lg);
  background: var(--accent);
  border: none;
  border-radius: var(--radius-full);
  padding: clamp(0.875rem, 2vw, 1rem) clamp(1.25rem, 3vw, 1.5rem);
  cursor: pointer;
  box-shadow: var(--shadow-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  transition: all var(--transition-base);
  z-index: 999;
}

.customer-service-trigger:hover {
  background: var(--accent-hover);
  transform: translateY(-4px);
  box-shadow: var(--shadow-accent);
}

.cs-icon {
  width: clamp(22px, 5.5vw, 26px);
  height: clamp(22px, 5.5vw, 26px);
  color: #FFFFFF;
}

.cs-text {
  font-family: var(--font-body);
  font-size: clamp(0.9375rem, 2.2vw, 1rem);
  font-weight: 600;
  color: #FFFFFF;
  letter-spacing: 0.01em;
}

@media (max-width: 640px) {
  .cs-text {
    display: none;
  }
  .customer-service-trigger {
    width: clamp(56px, 15vw, 60px);
    height: clamp(56px, 15vw, 60px);
    padding: 0;
    justify-content: center;
    bottom: var(--spacing-lg);
    right: var(--spacing-md);
  }
}

.chat-window {
  position: fixed;
  bottom: clamp(5rem, 12vh, 7rem);
  right: var(--spacing-lg);
  width: min(440px, calc(100vw - 2rem));
  height: min(600px, 70vh);
  background: var(--surface-1);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  display: none;
  flex-direction: column;
  z-index: 1000;
  overflow: hidden;
  border: 1px solid var(--border-light);
}

@media (max-width: 640px) {
  .chat-window {
    bottom: 0;
    right: 0;
    width: 100vw;
    height: 100vh;
    border-radius: 0;
  }
}

.chat-window.active {
  display: flex;
  animation: slideUp 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.chat-header {
  background: var(--accent);
  padding: var(--spacing-md) var(--spacing-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.chat-title {
  font-family: var(--font-display);
  font-size: clamp(1.0625rem, 2.6vw, 1.1875rem);
  font-weight: 600;
  color: #FFFFFF;
  letter-spacing: -0.01em;
}

.chat-close {
  background: rgba(255, 255, 255, 0.15);
  border: none;
  width: clamp(32px, 8.5vw, 36px);
  height: clamp(32px, 8.5vw, 36px);
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
  color: #FFFFFF;
}

.chat-close:hover {
  background: rgba(255, 255, 255, 0.25);
  transform: rotate(90deg);
}

.chat-close svg {
  width: clamp(18px, 5vw, 20px);
  height: clamp(18px, 5vw, 20px);
}

.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: var(--spacing-lg);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  background: var(--surface-0);
}

.chat-message {
  display: flex;
  gap: var(--spacing-sm);
  align-items: flex-end;
  animation: messageIn 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes messageIn {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.chat-message.user {
  flex-direction: row-reverse;
}

.message-avatar {
  width: clamp(32px, 8.5vw, 36px);
  height: clamp(32px, 8.5vw, 36px);
  border-radius: 50%;
  background: var(--accent-lighter);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  font-weight: 600;
  font-size: clamp(0.75rem, 2vw, 0.875rem);
  border: 1px solid var(--accent-light);
}

.message-content {
  max-width: 70%;
  background: var(--surface-1);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  font-size: clamp(0.9375rem, 2.2vw, 1rem);
  line-height: 1.6;
  word-wrap: break-word;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
}

.chat-message.user .message-content {
  background: var(--accent);
  color: #FFFFFF;
  border: none;
  box-shadow: var(--shadow-sm);
}

.message-image {
  max-width: clamp(160px, 42vw, 220px);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: transform 0.25s ease;
  box-shadow: var(--shadow-sm);
}

.message-image:hover {
  transform: scale(1.08);
  box-shadow: var(--shadow-md);
}

.chat-input-area {
  background: var(--surface-1);
  padding: var(--spacing-md) var(--spacing-lg);
  display: flex;
  gap: var(--spacing-sm);
  border-top: 1px solid var(--border-light);
}

.image-upload-btn {
  background: transparent;
  border: none;
  width: clamp(38px, 10.5vw, 42px);
  height: clamp(38px, 10.5vw, 42px);
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  transition: all 0.2s ease;
  flex-shrink: 0;
}

.image-upload-btn:hover {
  background: var(--accent-lighter);
  color: var(--accent);
  transform: scale(1.08);
}

.image-upload-btn svg {
  width: clamp(20px, 5.5vw, 24px);
  height: clamp(20px, 5.5vw, 24px);
}

.chat-input {
  flex: 1;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: clamp(0.625rem, 1.5vw, 0.75rem) var(--spacing-md);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: clamp(0.9375rem, 2.2vw, 1rem);
  resize: none;
  max-height: clamp(100px, 26vw, 120px);
  transition: all 0.2s ease;
}

.chat-input:focus {
  outline: none;
  border-color: var(--accent);
  background: var(--surface-1);
  box-shadow: 0 0 0 2px var(--accent-shadow);
}

.chat-send {
  background: var(--accent);
  border: none;
  border-radius: var(--radius-sm);
  padding: clamp(0.625rem, 1.5vw, 0.75rem) clamp(1.125rem, 2.8vw, 1.375rem);
  color: #FFFFFF;
  font-family: var(--font-body);
  font-size: clamp(0.9375rem, 2.2vw, 1rem);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  flex-shrink: 0;
  box-shadow: none;
}

.chat-send:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

.chat-send:active {
  transform: translateY(0);
}

.chat-send:disabled {
  background: var(--surface-3);
  color: var(--text-muted);
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

::-webkit-scrollbar {
  width: clamp(6px, 1.8vw, 8px);
}

::-webkit-scrollbar-track {
  background: var(--surface-2);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb {
  background: var(--surface-4);
  border-radius: var(--radius-full);
  transition: background 0.2s ease;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent);
}