:root {
  --primary-color: #2E7D32;
  --primary-dark: #1B5E20;
  --primary-light: #4CAF50;
  --secondary-color: #FF9800;
  --error-color: #F44336;
  --warning-color: #FFC107;
  --background-color: #121212;
  --surface-color: #1E1E1E;
  --text-primary: #FFFFFF;
  --text-secondary: #CCCCCC;
  --text-disabled: #666666;
  --border-color: #333333;
  --shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
  --border-radius: 12px;
  --transition: all 0.3s ease;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background: var(--background-color);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.container {
  max-width: 100%;
  min-height: 100vh;
  padding: 0;
  background: var(--background-color);
}

/* 状态栏样式 */
.status-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  background: var(--surface-color);
  border-bottom: 1px solid var(--border-color);
}

.gps-status {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
}

.gps-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--error-color);
  transition: var(--transition);
}

.gps-dot.good { background: #4CAF50; }
.gps-dot.fair { background: #FF9800; }
.gps-dot.poor { background: #F44336; }

.current-time {
  font-size: 14px;
  font-weight: 500;
}

.fullscreen-btn {
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 18px;
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 4px;
  transition: var(--transition);
}

.fullscreen-btn:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* 主显示区域 */
.main-display {
  padding: 40px 20px;
  text-align: center;
  background: linear-gradient(135deg, var(--surface-color) 0%, var(--background-color) 100%);
  transition: var(--transition);
}

.main-display.riding {
  background: linear-gradient(135deg, var(--primary-dark) 0%, var(--surface-color) 100%);
}

.speed-container {
  margin-bottom: 20px;
}

.current-speed {
  font-size: 4rem;
  font-weight: 300;
  line-height: 1;
  margin-bottom: 8px;
  transition: var(--transition);
}

.speed-unit {
  font-size: 1.2rem;
  color: var(--text-secondary);
}

.signal-quality {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* 指标网格 */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  padding: 20px;
}

.metric-card {
  background: var(--surface-color);
  padding: 16px;
  border-radius: var(--border-radius);
  text-align: center;
  border: 1px solid var(--border-color);
  transition: var(--transition);
}

.metric-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.metric-value {
  font-size: 1.8rem;
  font-weight: 600;
  margin-bottom: 4px;
  color: var(--primary-light);
}

.metric-label {
  font-size: 0.8rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* 控制按钮 */
.controls {
  display: flex;
  gap: 12px;
  padding: 20px;
  justify-content: center;
}

.btn {
  background: var(--primary-color);
  color: white;
  border: none;
  padding: 12px 24px;
  border-radius: 24px;
  font-size: 16px;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  min-width: 120px;
}

.btn:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
}

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

.btn.secondary {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.btn.secondary:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* 响应式设计 */
@media (min-width: 768px) {
  .metrics-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .current-speed {
    font-size: 5rem;
  }
}

@media (min-width: 1024px) {
  .metrics-grid {
    grid-template-columns: repeat(6, 1fr);
  }
  
  .container {
    max-width: 1200px;
    margin: 0 auto;
  }
}

/* 深色模式优化 */
@media (prefers-color-scheme: light) {
  :root {
    --background-color: #f5f5f5;
    --surface-color: #ffffff;
    --text-primary: #333333;
    --text-secondary: #666666;
    --border-color: #e0e0e0;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  }
}

/* 无障碍支持 */
@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
    animation: none !important;
  }
}

/* 高对比度模式 */
@media (prefers-contrast: high) {
  :root {
    --border-color: #000000;
    --shadow: 0 0 0 1px #000000;
  }
}