/* ==========================================================================
   方案 C · 云梯之环 | YYT-ORBIT-C03 核心全局样式与设计令牌
   ========================================================================== */

:root {
  --bg-main: #070B1D;
  --bg-secondary: #111831;
  --bg-surface: #151D3B;
  --space-purple: #292451;
  --aurora-purple: #9A86F5;
  --ice-blue: #91DDF7;
  --ice-blue-glow: rgba(145, 221, 247, 0.35);
  --text-primary: #F3F5FF;
  --text-muted: #AEB9D7;
  --border-subtle: rgba(220, 230, 255, 0.15);
  --border-highlight: rgba(145, 221, 247, 0.45);
  --glow-ambient: rgba(154, 134, 245, 0.22);
  --glow-strong: rgba(145, 221, 247, 0.3);

  --font-sans: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Segoe UI', Roboto, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --font-mono: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace;

  --container-max: 1280px;
  --container-narrow: 840px;
  --header-height: 80px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 24px;
  --radius-full: 9999px;

  --transition-smooth: all 0.28s cubic-bezier(0.16, 1, 0.3, 1);
}

/* 基础重置 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 20px);
  background-color: var(--bg-main);
  color: var(--text-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-primary);
  line-height: 1.65;
  overflow-x: hidden;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* 键盘可访问性焦点状态 */
:focus-visible {
  outline: 2px solid var(--ice-blue);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}

/* 无障碍跳过导航 */
.skip-to-content {
  position: absolute;
  top: -100px;
  left: 20px;
  background: var(--ice-blue);
  color: #070B1D;
  padding: 12px 20px;
  font-weight: 700;
  border-radius: var(--radius-sm);
  z-index: 9999;
  text-decoration: none;
  transition: top 0.2s ease;
}
.skip-to-content:focus {
  top: 20px;
}

/* 容器定义 */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: clamp(20px, 4vw, 48px);
  padding-right: clamp(20px, 4vw, 48px);
}

.container-narrow {
  max-width: var(--container-narrow);
}

/* 按钮规范 (满足至少 44x44px 触控要求) */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 48px;
  padding: 0 clamp(24px, 3vw, 36px);
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  transition: var(--transition-smooth);
  user-select: none;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--ice-blue) 0%, var(--aurora-purple) 100%);
  color: #070B1D;
  box-shadow: 0 4px 24px var(--glow-ambient);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 32px var(--glow-strong);
  filter: brightness(1.08);
}
.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background: rgba(220, 230, 255, 0.05);
  color: var(--text-primary);
  border-color: var(--border-subtle);
  backdrop-filter: blur(12px);
}
.btn-secondary:hover {
  background: rgba(220, 230, 255, 0.12);
  border-color: var(--ice-blue);
  color: var(--ice-blue);
  transform: translateY(-2px);
}

/* 减弱动画适配 */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}