/* ════════════════════════════════════════════════════════════
   global.css  —  全站通用基础样式
   包含：CSS 变量、重置、导航栏、底部备案、星云层、工具类
   ════════════════════════════════════════════════════════════ */

/* ─── Google Fonts 引入（由各 HTML 页面 <link> 统一加载） ─── */

/* ─── CSS 全局变量 ─── */
:root {
  /* 背景色 */
  --c-bg:       #07080f;
  --c-bg2:      #0d101e;
  --c-card:     rgba(8, 14, 30, 0.72);
  --c-card-hov: rgba(0, 212, 255, 0.06);

  /* 辉光色系 */
  --c-cyan:       #00d4ff;
  --c-cyan-dim:   rgba(0, 212, 255, 0.35);
  --c-cyan-faint: rgba(0, 212, 255, 0.1);
  --c-purple:     #8b5cf6;
  --c-purple-dim: rgba(139, 92, 246, 0.35);
  --c-teal:       #00ffcc;

  /* 排名辉光 */
  --c-gold:    #ffd700;
  --c-silver:  #c0d0e8;
  --c-bronze:  #cd8c46;

  /* 文字 */
  --c-text:   #b0cae8;
  --c-text2:  #607898;
  --c-text3:  #324560;
  --c-white:  #e8f4ff;

  /* 辉光预设 */
  --glow-c-sm:  0 0 8px rgba(0,212,255,.55), 0 0 16px rgba(0,212,255,.3);
  --glow-c-md:  0 0 15px rgba(0,212,255,.65), 0 0 35px rgba(0,212,255,.4), 0 0 70px rgba(0,212,255,.18);
  --glow-c-lg:  0 0 25px rgba(0,212,255,.8), 0 0 55px rgba(0,212,255,.55), 0 0 100px rgba(0,212,255,.28);
  --glow-p-md:  0 0 15px rgba(139,92,246,.65), 0 0 35px rgba(139,92,246,.4), 0 0 70px rgba(139,92,246,.18);

  /* 字体 */
  --f-sci:  'Orbitron', 'Rajdhani', sans-serif;
  --f-body: 'Rajdhani', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --f-cn:   'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;

  /* 圆角 */
  --r-sm: 4px;
  --r-md: 8px;
  --r-lg: 14px;

  /* 过渡 */
  --ease-fast: .18s ease;
  --ease-med:  .35s ease;
  --ease-slow: .65s cubic-bezier(.22,.68,0,1.2);
}

/* ─── 全局重置 ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  background: var(--c-bg);
  color: var(--c-text);
  font-family: var(--f-body);
  line-height: 1.65;
  min-height: 100vh;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

/* ─── 星空 Canvas 背景（position:fixed，全部页面共用） ─── */
#star-canvas {
  position: fixed;
  inset: 0;
  width: 100%; height: 100%;
  z-index: 0;
  pointer-events: none;
}

/* ─── CSS 星云漂移层（叠在 canvas 之上） ─── */
.nebula-bg {
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  overflow: hidden;
}
.nebula-bg::before {
  content: '';
  position: absolute;
  width: 90vw; height: 90vw;
  border-radius: 50%;
  background: radial-gradient(circle,
    rgba(139,92,246,.14) 0%,
    rgba(0,212,255,.06) 40%,
    transparent 68%);
  top: -30vw; left: -25vw;
  animation: nebulaDrift 42s ease-in-out infinite alternate;
  filter: blur(48px);
}
.nebula-bg::after {
  content: '';
  position: absolute;
  width: 65vw; height: 65vw;
  border-radius: 50%;
  background: radial-gradient(circle,
    rgba(0,212,255,.09) 0%,
    rgba(139,92,246,.05) 45%,
    transparent 70%);
  bottom: -15vw; right: -15vw;
  animation: nebulaDrift 38s ease-in-out infinite alternate-reverse;
  filter: blur(55px);
}
@keyframes nebulaDrift {
  0%   { transform: translate(0,0) scale(1); }
  33%  { transform: translate(4vw, 3vw) scale(1.06); }
  66%  { transform: translate(-3vw, 5vw) scale(.96); }
  100% { transform: translate(5vw,-3vw) scale(1.04); }
}

/* ─── 页面内容层 ─── */
.page-wrap { position: relative; z-index: 10; }

/* ══════════════════════════════════════════════════════════
   导航栏（适用除首页外的所有 6 个页面）
   ══════════════════════════════════════════════════════════ */
.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 900;
  height: 62px;
  background: rgba(5,8,18,.8);
  backdrop-filter: blur(22px);
  -webkit-backdrop-filter: blur(22px);
  border-bottom: 1px solid rgba(0,212,255,.13);
  box-shadow: 0 0 0 0 transparent, 0 2px 40px rgba(0,0,0,.55);
}

.nav-inner {
  display: flex;
  align-items: center;
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 2rem;
  height: 100%;
  gap: 0;
}

/* ── Logo ── */
.nav-logo {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: .28rem;          /* 两行之间留出间距 */
  margin-right: 2.4rem;
  flex-shrink: 0;
  text-decoration: none;
}
.logo-title {
  font-family: var(--f-sci);
  font-size: 1.18rem;
  font-weight: 700;
  letter-spacing: .05em;
  background: linear-gradient(110deg, var(--c-cyan) 0%, var(--c-purple) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  filter: drop-shadow(0 0 8px rgba(0,212,255,.6));
  line-height: 1;
}
.logo-domain {
  font-family: var(--f-sci);
  font-size: .62rem;
  /* letter-spacing 撑宽到与 logo-title 视觉等宽 */
  letter-spacing: .42em;
  color: var(--c-text2);
  line-height: 1;
}

/* ── 导航链接区 ── */
.nav-links {
  display: flex;
  align-items: center;
  height: 100%;
  flex: 1;
}

.nav-item {
  position: relative;
  height: 62px;
  display: flex;
  align-items: center;
}
.nav-item > a {
  display: flex;
  align-items: center;
  height: 100%;
  padding: 0 1.15rem;
  font-family: var(--f-sci);
  font-size: .8rem;
  font-weight: 500;
  letter-spacing: .05em;
  color: var(--c-text2);
  white-space: nowrap;
  transition: color var(--ease-fast);
  user-select: none;
}
.nav-item > a:hover { color: var(--c-cyan); }
.nav-item.active > a { color: var(--c-cyan); }

/* 有下拉的按钮显示箭头 */
.nav-item.has-dropdown > a::after {
  content: '▾';
  margin-left: .35rem;
  font-size: .6rem;
  opacity: .55;
  transition: transform var(--ease-fast);
}
.nav-item.has-dropdown:hover > a::after { transform: rotate(180deg); }

/* ── 下拉菜单 ── */
.nav-dropdown-menu {
  position: absolute;
  top: 100%;          /* 紧贴导航栏底部，无间隙 */
  left: 0;
  min-width: 165px;
  background: rgba(4,8,20,.94);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid rgba(0,212,255,.2);
  border-top: 2px solid var(--c-cyan);
  border-radius: 0 0 var(--r-md) var(--r-md);
  box-shadow: 0 10px 40px rgba(0,0,0,.7), var(--glow-c-sm);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-6px);
  transition: opacity .22s ease, visibility .22s ease, transform .22s ease;
  overflow: hidden;
}
/* 父项或菜单自身悬停时保持展开 */
.nav-item.has-dropdown:hover .nav-dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.nav-dropdown-menu a {
  display: flex;
  align-items: center;
  padding: .72rem 1.2rem;
  font-family: var(--f-sci);
  font-size: .72rem;
  letter-spacing: .06em;
  color: var(--c-text);
  border-bottom: 1px solid rgba(0,212,255,.07);
  position: relative;
  transition: color var(--ease-fast), background var(--ease-fast), padding-left .2s ease;
}
.nav-dropdown-menu a:last-child { border-bottom: none; }
.nav-dropdown-menu a::before {
  content: '';
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--c-cyan), var(--c-purple));
  transform: scaleY(0);
  transition: transform .2s ease;
  box-shadow: var(--glow-c-sm);
}
.nav-dropdown-menu a:hover {
  color: var(--c-cyan);
  background: rgba(0,212,255,.055);
  padding-left: 1.7rem;
}
.nav-dropdown-menu a:hover::before { transform: scaleY(1); }

/* ── 提交成绩按钮 ── */
.nav-submit {
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  padding: .45rem 1.3rem;
  font-family: var(--f-sci);
  font-size: .78rem;
  font-weight: 600;
  letter-spacing: .1em;
  color: var(--c-cyan);
  border: 1px solid var(--c-cyan-dim);
  border-radius: var(--r-sm);
  background: rgba(0,212,255,.07);
  transition: all var(--ease-slow);
  white-space: nowrap;
  flex-shrink: 0;
}
.nav-submit:hover {
  color: #000;
  background: var(--c-cyan);
  border-color: var(--c-cyan);
  box-shadow: var(--glow-c-md);
  transform: translateY(-1px);
}

/* ── 汉堡菜单（移动端） ── */
.nav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px; height: 36px;
  background: none;
  border: none;
  cursor: pointer;
  margin-left: auto;
  padding: 4px;
  flex-shrink: 0;
}
.nav-hamburger span {
  display: block;
  width: 100%; height: 1.5px;
  background: var(--c-text);
  border-radius: 2px;
  transition: all .3s ease;
}
.nav-hamburger.open span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.nav-hamburger.open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.nav-hamburger.open span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

/* ══════════════════════════════════════════════════════════
   底部备案区（通用，首页通过 .home-footer 类控制显示）
   ══════════════════════════════════════════════════════════ */
.site-footer {
  position: relative;
  z-index: 10;
  padding: 2.5rem 1rem 2rem;
  text-align: center;
  border-top: 1px solid rgba(0,212,255,.07);
  margin-top: 5rem;
}
.site-footer a,
.site-footer p {
  color: var(--c-text3);
  font-size: .75rem;
  font-family: var(--f-sci);
  letter-spacing: .06em;
  display: block;
  line-height: 2;
  transition: color var(--ease-fast);
}
.site-footer a:hover { color: var(--c-text2); }

/* ══════════════════════════════════════════════════════════
   移动端响应式
   ══════════════════════════════════════════════════════════ */
@media (max-width: 860px) {
  .nav-hamburger { display: flex; }

  /* 导航链接收起为抽屉 */
  .nav-links {
    position: fixed;
    top: 62px; left: 0; right: 0;
    background: rgba(4,8,20,.97);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(0,212,255,.13);
    flex-direction: column;
    align-items: flex-start;
    height: auto;
    max-height: 0;
    overflow: hidden;
    transition: max-height .4s ease;
    z-index: 800;
  }
  .nav-links.open { max-height: 80vh; overflow-y: auto; }

  .nav-item {
    width: 100%;
    height: auto;
    flex-direction: column;
    align-items: flex-start;
  }
  .nav-item > a {
    width: 100%;
    height: auto;
    padding: .9rem 1.5rem;
    border-bottom: 1px solid rgba(0,212,255,.06);
    font-size: .78rem;
  }

  /* 移动端下拉菜单改为点击展开 */
  .nav-dropdown-menu {
    position: static;
    opacity: 0;
    visibility: hidden;
    transform: none;
    border: none;
    border-radius: 0;
    box-shadow: none;
    max-height: 0;
    padding: 0;
    transition: max-height .3s ease, opacity .3s ease, visibility .3s ease;
    background: rgba(0,0,0,.3);
    backdrop-filter: none;
  }
  .nav-item.has-dropdown.mob-open .nav-dropdown-menu {
    opacity: 1;
    visibility: visible;
    max-height: 200px;
  }
  .nav-dropdown-menu a { padding-left: 2.5rem; }

  /* 移动端提交按钮：紧跟汉堡键，不再 margin-left:auto */
  .nav-submit {
    margin-left: .6rem;
    padding: .38rem .85rem;
    font-size: .62rem;
    letter-spacing: .07em;
  }
  /* nav-links 是 fixed 不占位，所以 nav-inner 只剩 logo + hamburger + submit */
  /* hamburger 的 margin-left:auto 会把 hamburger+submit 推到最右侧 */
}