/* ==========================================================================
   素养星计划 · 基础层
   样式重置 / 排版规范 / 布局容器 / 星空背景 / 响应式断点
   ========================================================================== */

*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  font-weight: var(--fw-regular);
  line-height: var(--lh-body);
  color: var(--t-1);
  background-color: var(--c-space);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-weight: var(--fw-bold);
  line-height: var(--lh-tight);
  letter-spacing: var(--ls-tight);
}

p { margin: 0; }

ul, ol { margin: 0; padding: 0; list-style: none; }

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

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

button, input, select, textarea {
  font: inherit;
  color: inherit;
  margin: 0;
}

button {
  border: 0;
  background: none;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

input, textarea, select { background: none; }

table { border-collapse: collapse; width: 100%; }

/* hidden 属性优先级高于组件 display 声明，避免元素该隐藏时仍显示 */
[hidden] { display: none !important; }

hr {
  border: 0;
  height: 1px;
  background: var(--g-line);
  margin: var(--sp-7) 0;
}

/* 可见焦点环：键盘用户可感知，鼠标用户不打扰 */
:focus { outline: none; }
:focus-visible {
  outline: 2px solid var(--c-cyan);
  outline-offset: 3px;
  border-radius: var(--r-xs);
}

::selection {
  background: rgba(109, 91, 255, .45);
  color: #fff;
}

/* ---------- 自定义滚动条（桌面端） ---------- */
@media (min-width: 1024px) {
  ::-webkit-scrollbar { width: 10px; height: 10px; }
  ::-webkit-scrollbar-track { background: var(--c-space); }
  ::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, .14);
    border-radius: var(--r-full);
    border: 2px solid var(--c-space);
  }
  ::-webkit-scrollbar-thumb:hover { background: rgba(109, 91, 255, .6); }
}

/* ==========================================================================
   星空背景层
   ========================================================================== */

.sky {
  position: fixed;
  inset: 0;
  z-index: var(--z-bg);
  pointer-events: none;
  overflow: hidden;
  background: var(--c-space);
}

.sky__aurora {
  position: absolute;
  inset: -20% -10% auto -10%;
  height: 120vh;
  background: var(--g-aurora);
  filter: blur(10px);
  opacity: .95;
  animation: aurora-drift 26s var(--e-out) infinite alternate;
}

.sky__grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, .035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, .035) 1px, transparent 1px);
  background-size: 72px 72px;
  mask-image: radial-gradient(120% 80% at 50% 0%, #000 0%, transparent 78%);
  -webkit-mask-image: radial-gradient(120% 80% at 50% 0%, #000 0%, transparent 78%);
}

.sky__stars {
  position: absolute;
  inset: 0;
  background-repeat: repeat;
  opacity: .7;
}

.sky__stars--sm {
  background-image:
    radial-gradient(1px 1px at 12px 24px, rgba(255, 255, 255, .85), transparent),
    radial-gradient(1px 1px at 96px 78px, rgba(255, 255, 255, .55), transparent),
    radial-gradient(1px 1px at 168px 132px, rgba(0, 210, 255, .75), transparent),
    radial-gradient(1px 1px at 216px 40px, rgba(255, 255, 255, .6), transparent),
    radial-gradient(1px 1px at 58px 186px, rgba(109, 91, 255, .8), transparent),
    radial-gradient(1px 1px at 248px 208px, rgba(255, 255, 255, .45), transparent);
  background-size: 288px 288px;
  animation: twinkle 5.5s ease-in-out infinite alternate;
}

.sky__stars--lg {
  background-image:
    radial-gradient(1.6px 1.6px at 84px 60px, rgba(255, 255, 255, .95), transparent),
    radial-gradient(1.6px 1.6px at 320px 190px, rgba(255, 197, 61, .85), transparent),
    radial-gradient(1.6px 1.6px at 460px 96px, rgba(255, 255, 255, .7), transparent),
    radial-gradient(1.6px 1.6px at 210px 320px, rgba(0, 210, 255, .8), transparent);
  background-size: 520px 520px;
  animation: twinkle 7.5s ease-in-out infinite alternate-reverse;
}

.sky__beam {
  position: absolute;
  top: -30%;
  left: 50%;
  width: 1px;
  height: 160%;
  background: var(--g-line);
  opacity: .5;
  transform: rotate(18deg);
  transform-origin: center;
}

@keyframes aurora-drift {
  from { transform: translate3d(0, 0, 0) scale(1); }
  to   { transform: translate3d(-3%, 3%, 0) scale(1.08); }
}

@keyframes twinkle {
  from { opacity: .35; }
  to   { opacity: .8; }
}

/* ==========================================================================
   布局容器与栅格
   ========================================================================== */

.page {
  position: relative;
  z-index: var(--z-content);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.page__main {
  flex: 1;
  padding-bottom: calc(var(--h-tabbar) + var(--sp-8));
}

.container {
  width: 100%;
  max-width: var(--w-container);
  margin: 0 auto;
  padding: 0 var(--sp-5);
}

.section {
  padding: var(--sp-9) 0;
}

.section--tight { padding: var(--sp-7) 0; }

.section--light {
  background: var(--c-light-bg);
  color: var(--c-ink);
  border-radius: var(--r-xl) var(--r-xl) 0 0;
}

.grid {
  display: grid;
  gap: var(--sp-5);
  grid-template-columns: 1fr;
}

.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

/* ---------- 排版工具类 ---------- */

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 6px 14px;
  font-size: var(--fs-xs);
  font-weight: var(--fw-semi);
  letter-spacing: var(--ls-wide);
  color: #c8cfff;
  background: var(--glass-bg-2);
  border: 1px solid var(--glass-border);
  border-radius: var(--r-full);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
}

.section-title {
  font-size: var(--fs-h2);
  font-weight: var(--fw-bold);
}

.section-lead {
  max-width: 620px;
  color: var(--t-2);
  font-size: var(--fs-body);
}

.text-brand {
  background: var(--g-brand);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.text-gold {
  background: var(--g-gold);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.text-muted { color: var(--t-3); }

.num {
  font-family: var(--font-num);
  font-weight: var(--fw-bold);
  letter-spacing: -0.01em;
  font-variant-numeric: tabular-nums;
}

/* ---------- 滚动渐显 ---------- */

.reveal {
  opacity: 0;
  transform: translate3d(0, 26px, 0);
  transition:
    opacity var(--d-slower) var(--e-out),
    transform var(--d-slower) var(--e-out);
  will-change: opacity, transform;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

.delay-1 { transition-delay: 80ms; }
.delay-2 { transition-delay: 160ms; }
.delay-3 { transition-delay: 240ms; }
.delay-4 { transition-delay: 320ms; }

/* ---------- 无障碍：屏幕阅读器专用 ---------- */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* 跳转到主内容 */
.skip-link {
  position: absolute;
  top: -60px;
  left: var(--sp-5);
  z-index: var(--z-toast);
  padding: 10px 18px;
  background: var(--c-violet);
  color: #fff;
  border-radius: 0 0 var(--r-sm) var(--r-sm);
  transition: top var(--d-base) var(--e-out);
}

.skip-link:focus { top: 0; }

/* ==========================================================================
   响应式断点
   ========================================================================== */

@media (max-width: 1023px) {
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 767px) {
  :root {
    --fs-display: 30px;
    --fs-h1: 26px;
    --fs-h2: 21px;
    --fs-h3: 18px;
    --fs-sub: 16px;
    --sp-9: 44px;
    --sp-10: 52px;
    --sp-11: 64px;
  }

  .container { padding: 0 var(--sp-4); }
  .grid--2, .grid--3, .grid--4 { grid-template-columns: 1fr; }
  .section { padding: var(--sp-8) 0; }
}

/* ==========================================================================
   尊重系统的“减少动态效果”偏好
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }

  .reveal {
    opacity: 1 !important;
    transform: none !important;
  }
}