/* ============================================================
   听风沐芳华学菀 · TingFengMu
   设计令牌 Design Tokens —— 星空蓝色科技风
   ============================================================ */

:root {
  /* —— 星空色板 —— */
  --space-900: #03050f;
  --space-800: #070b22;
  --space-700: #0b1230;
  --space-600: #111a42;
  --space-500: #1a2552;

  /* —— 主色：星空蓝 —— */
  --star-blue: #2b6cff;
  --star-blue-light: #4d8bff;
  --star-blue-dark: #1747b8;
  --star-cyan: #22d3ee;
  --star-violet: #7c5cff;

  /* —— 渐变 —— */
  --grad-primary: linear-gradient(135deg, #4d8bff 0%, #22d3ee 100%);
  --grad-cosmic: linear-gradient(135deg, #7c5cff 0%, #2b6cff 50%, #22d3ee 100%);
  --grad-text: linear-gradient(135deg, #8fb8ff 0%, #22d3ee 60%, #b08bff 100%);
  --grad-card: linear-gradient(160deg, rgba(43,108,255,0.12) 0%, rgba(34,211,238,0.04) 100%);

  /* —— 中性 —— */
  --text-1: #eaf0ff;
  --text-2: #a8b3d1;
  --text-3: #6c78a0;
  --line: rgba(120, 150, 220, 0.14);
  --line-strong: rgba(120, 150, 220, 0.28);

  /* —— 表面 —— */
  --surface: rgba(18, 26, 66, 0.55);
  --surface-2: rgba(27, 38, 88, 0.6);
  --surface-solid: #0d1538;

  /* —— 状态 —— */
  --ok: #34d399;
  --warn: #fbbf24;
  --danger: #f87171;

  /* —— 特效 —— */
  --glow-blue: 0 0 24px rgba(43, 108, 255, 0.45);
  --glow-cyan: 0 0 24px rgba(34, 211, 238, 0.4);
  --shadow-card: 0 18px 48px -12px rgba(2, 6, 23, 0.7);
  --shadow-float: 0 30px 70px -15px rgba(43, 108, 255, 0.25);

  /* —— 圆角 —— */
  --r-xs: 6px;
  --r-sm: 10px;
  --r-md: 16px;
  --r-lg: 24px;
  --r-xl: 32px;
  --r-pill: 999px;

  /* —— 动效 —— */
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
  --t-fast: 180ms;
  --t-base: 320ms;
  --t-slow: 600ms;

  /* —— 布局 —— */
  --nav-h: 72px;
  --container: 1180px;
}

/* ===== Reset ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-h);
}

body {
  font-family: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  background-color: var(--space-900);
  background-image:
    radial-gradient(1200px 600px at 80% -10%, rgba(124, 92, 255, 0.15), transparent 60%),
    radial-gradient(900px 500px at 0% 10%, rgba(43, 108, 255, 0.12), transparent 55%);
  background-attachment: fixed;
  color: var(--text-1);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  min-height: 100vh;
}

img,
svg {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

input,
textarea {
  font: inherit;
  color: inherit;
}

/* ===== 背景画布 ===== */
.starfield {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
}

.aurora {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.5;
  background:
    radial-gradient(600px 300px at 15% 20%, rgba(43, 108, 255, 0.08), transparent 70%),
    radial-gradient(500px 400px at 85% 70%, rgba(124, 92, 255, 0.07), transparent 70%),
    radial-gradient(700px 350px at 50% 100%, rgba(34, 211, 238, 0.06), transparent 70%);
  animation: auroraShift 20s ease-in-out infinite alternate;
}

@keyframes auroraShift {
  0%   { transform: translate3d(0, 0, 0) scale(1); }
  50%  { transform: translate3d(-2%, 1%, 0) scale(1.05); }
  100% { transform: translate3d(2%, -1%, 0) scale(1); }
}

/* ===== 布局 ===== */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

main,
.section,
footer {
  position: relative;
  z-index: 1;
}

/* ===== 排版 ===== */
.gradient {
  background: var(--grad-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.section {
  padding: clamp(64px, 10vw, 120px) 0;
  position: relative;
}

.section-alt {
  background:
    linear-gradient(180deg, transparent, rgba(11, 18, 48, 0.6) 50%, transparent);
}

.section-head {
  text-align: center;
  max-width: 680px;
  margin: 0 auto clamp(40px, 6vw, 64px);
}

.section-kicker {
  display: inline-block;
  font-family: 'Orbitron', sans-serif;
  font-size: 12px;
  letter-spacing: 0.3em;
  color: var(--star-blue-light);
  margin-bottom: 14px;
  text-transform: uppercase;
}

.section-title {
  font-size: clamp(26px, 4vw, 42px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

.section-sub {
  color: var(--text-2);
  margin-top: 14px;
  font-size: 16px;
}

/* ===== 页面 Hero ===== */
.page-hero {
  padding: calc(var(--nav-h) + 64px) 0 48px;
  text-align: center;
}

.page-title {
  font-size: clamp(30px, 5vw, 52px);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.page-sub {
  color: var(--text-2);
  margin-top: 16px;
  font-size: 17px;
}

/* ===== 工具类 ===== */
.card-glow {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: var(--shadow-card);
  overflow: hidden;
}

.card-glow::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 1px;
  background: linear-gradient(135deg, rgba(77,139,255,0.5), rgba(34,211,238,0.1) 40%, transparent 70%);
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  pointer-events: none;
}

.has-js [data-reveal] {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity var(--t-slow) var(--ease-out), transform var(--t-slow) var(--ease-out);
}

.has-js [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
  .container { padding: 0 18px; }
}

/* ===== 可访问性 ===== */
:focus-visible {
  outline: 2px solid var(--star-blue-light);
  outline-offset: 3px;
  border-radius: var(--r-xs);
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

/* ===== 图标符号（无 emoji 版本，使用文字符号替代） ===== */
.feature-icon::before { content: "◆"; color: var(--star-blue-light); font-size: 22px; }
.contact-icon::before { content: "●"; color: var(--star-blue-light); font-size: 14px; margin-right: 2px; }
.hero-qq-icon::before { content: "Q"; color: var(--primary); font-weight: 700; font-size: 18px; }
.user-hero-icon::before { content: "◆"; color: var(--star-blue-light); font-size: 40px; }
.sb-icon::before { content: "▸"; color: var(--star-blue-light); font-size: 18px; }
.pay-method-icon::before { content: "◇"; color: var(--star-blue-light); font-size: 24px; }
.bs-search-icon::before { content: "⌕"; color: var(--text-3); font-size: 15px; }
.bs-empty-icon::before { content: "▯"; color: var(--text-3); font-size: 48px; }
.checkout-cart-icon::before { content: "▤"; color: var(--text-1); font-size: 22px; }
.result-icon::before { content: ""; color: #4ade80; font-size: 56px; }
.lock-icon::before { content: "◈"; color: var(--text-3); font-size: 52px; }
.reader-tools .btn-xs::before { /* 保持按钮文字 */ }