/* ============================================================
   103班：音乐领军班 · 布局与导航
   悬浮玻璃导航条(由 nav.js 动态注入) + 主题开关 + 手机菜单 + 底部
   ============================================================ */

/* ---- 顶部导航:悬浮玻璃条 ---- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  padding: 12px 20px;     /* 20px 是全站统一的内容边距,和下面的玻璃块左右对齐 */
  background: transparent;
  border: none;
  pointer-events: none;   /* 透明区域不挡点击,只有玻璃条本身可交互 */

  /* 导航的"墨水色"与玻璃底色,默认跟随主题;
     首页首屏会覆盖成深色版本(视频太亮,白字才压得住) */
  --nav-ink: var(--text);
  --nav-ink-dim: var(--muted);
  --nav-bg: var(--glass-bg);
  --nav-brd: var(--glass-brd);
}

.nav {
  pointer-events: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  height: 58px;
  padding: 0 10px 0 18px;
  border-radius: 999px;
  /* 掠光 + --nav-bg:首屏会临时把 --nav-bg 换成更深的版本,这里跟着一起变 */
  background: var(--glass-sheen), var(--nav-bg);
  -webkit-backdrop-filter: blur(26px) saturate(180%);
  backdrop-filter: blur(26px) saturate(180%);
  border: 1px solid var(--nav-brd);
  box-shadow: var(--glass-rim);
  /* 0.6s:和页面底色一起慢速淡变,切主题时不会"导航先变、背景后变" */
  transition: background-color 0.6s ease, border-color 0.6s ease, box-shadow 0.6s ease;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
}
.nav-logo img {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  box-shadow: 0 0 18px rgba(240, 185, 11, 0.28);
}
.nav-logo b {
  font-family: var(--font-display);
  font-size: 1.05rem;
  letter-spacing: 2px;
  color: var(--nav-ink);
  transition: color 0.6s ease;
}
.nav-logo small {
  display: block;
  font-size: 0.6rem;
  letter-spacing: 3px;
  color: var(--gold);
  text-transform: uppercase;
}

/* 桌面导航链接 */
.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
}
.nav-links a {
  position: relative;
  padding: 8px 15px;
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: 1.5px;
  font-size: 0.9rem;
  color: var(--nav-ink-dim);
  transition: color 0.6s ease;
}
.nav-links a::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 1px;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--gold), var(--gold-2));
  transform: translateX(-50%);
  transition: width 0.25s;
}
.nav-links a:hover { color: var(--nav-ink); }
.nav-links a:hover::after { width: 52%; }
.nav-links a.active { color: var(--gold); }
.nav-links a.active::after { width: 52%; }

/* ---- 深色/浅色开关:玻璃圆钮,图标随当前主题切换 ---- */
.theme-toggle {
  flex: none;
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--chip);
  border: 1px solid var(--nav-brd);
  color: var(--nav-ink);
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  transition: background-color 0.6s ease, color 0.6s ease, transform 0.25s ease, border-color 0.6s ease;
}
.theme-toggle:hover { transform: scale(1.08); background: var(--gold-soft); }
.theme-toggle:active { transform: scale(0.96); }
.theme-toggle:focus-visible { outline: 2px solid var(--gold); outline-offset: 2px; }
.theme-toggle svg { width: 19px; height: 19px; display: block; }

/* 深色下显示"太阳"(点了变浅色),浅色下显示"月亮" */
.theme-toggle .i-sun { display: block; }
.theme-toggle .i-moon { display: none; }
:root[data-theme="light"] .theme-toggle .i-sun { display: none; }
:root[data-theme="light"] .theme-toggle .i-moon { display: block; }

/* 汉堡按钮(手机才显示) */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: 1px solid var(--nav-brd);
  border-radius: 10px;
  padding: 10px 11px;
  cursor: pointer;
}
.nav-toggle span {
  width: 20px;
  height: 2px;
  background: var(--nav-ink);
  transition: 0.3s;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---- 底部信息栏:所有页面保持一致,固定不随滚动消失 ---- */
body { padding-bottom: 48px; } /* 给固定信息栏留出空间,避免遮住正文 */

.site-footer {
  position: fixed;
  left: 0; right: 0; bottom: 0;
  z-index: 150;
  padding: 10px 20px 13px;
  text-align: center;
  font-size: 0.68rem;
  letter-spacing: 0.15em;
  color: var(--faint);
  /* 玻璃底栏:全站统一的固定信息栏也做成毛玻璃 */
  background-color: var(--glass-bg);
  background-image: var(--glass-sheen);
  -webkit-backdrop-filter: blur(26px) saturate(180%);
  backdrop-filter: blur(26px) saturate(180%);
  border-top: 1px solid var(--glass-brd);
  box-shadow: var(--glass-rim);
  pointer-events: none; /* 不干扰主视觉与点击 */
  transition: color 0.6s ease, background-color 0.6s ease,
    border-color 0.6s ease, box-shadow 0.6s ease;
}
.site-footer b {
  color: var(--muted);
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: 0.2em;
  transition: color 0.6s ease;
}
.site-footer em { color: var(--gold); font-style: normal; opacity: 0.75; transition: color 0.6s ease; }
.site-footer i { display: inline-block; margin: 0 10px; font-style: normal; opacity: 0.5; }

/* ---- 各子页面共用页头(横幅) ---- */
.page-hero {
  padding: 84px 20px 64px;
  text-align: center;
  position: relative;
  overflow: hidden;
  /* 玻璃横幅:半透明 + 背景模糊 + 顶部内高光,替掉原来的实色渐变带 */
  background-color: var(--glass-bg);
  background-image: var(--glass-sheen),
    radial-gradient(circle at 50% -6%, var(--gold-soft), transparent 58%);
  -webkit-backdrop-filter: blur(26px) saturate(180%);
  backdrop-filter: blur(26px) saturate(180%);
  border-bottom: 1px solid var(--glass-brd);
  box-shadow: var(--glass-rim);
  animation: page-in 0.5s cubic-bezier(0.22, 1, 0.36, 1) both; /* 柔和落地 */
  transition: background-color 0.6s ease, border-color 0.6s ease, box-shadow 0.6s ease;
}
.page-hero .no {
  font-family: var(--font-latin);
  color: var(--gold);
  letter-spacing: 0.5em;      /* 极宽字距:稀疏高级感 */
  font-size: 0.8rem;
  font-weight: 500;
  text-transform: uppercase;
  transition: color 0.6s ease;
}
.page-hero h1 {
  font-family: var(--font-display);
  font-weight: 900;           /* 主标题极粗 */
  font-size: clamp(2.4rem, 7vw, 4.2rem);
  line-height: 1.1;
  letter-spacing: 0.08em;
  margin-top: 14px;
  view-transition-name: hero-title; /* 与首页主标题共享元素过渡 */
}
.page-hero p {
  color: var(--muted);
  margin-top: 18px;
  font-family: var(--font-latin);
  font-weight: 300;           /* 副信息细字重,与主标题形成反差 */
  letter-spacing: 0.35em;
  text-transform: uppercase;
  font-size: 0.8rem;
  opacity: 0.75;
  transition: color 0.6s ease;
}

/* 导航 Logo:子页面之间保持位置稳定 */
.nav-logo { view-transition-name: nav-logo; }

/* ---- 响应式 ---- */

/* 导航到 6 项后,窄一些的桌面窗口先收紧间距,别把「班级公告」挤到换行 */
@media (min-width: 821px) and (max-width: 1000px) {
  .nav-links a { padding: 8px 10px; font-size: 0.84rem; letter-spacing: 1px; }
  .nav .nav-logo b { font-size: 0.95rem; letter-spacing: 1px; }
}

@media (max-width: 820px) {
  .nav-toggle { display: flex; }

  /* 底部信息栏在手机上会折成两行,多留一点高度,别压住正文 */
  body { padding-bottom: 66px; }
  .site-footer { font-size: 0.62rem; letter-spacing: 0.08em; line-height: 1.6; }

  .nav-links {
    position: fixed;
    top: 82px;
    left: 20px;
    right: 20px;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 10px 14px 14px;
    border-radius: 24px;
    /* 用 --nav-bg:首页首屏(深色导航)时展开也是深色,不会白字白底 */
    background: var(--glass-sheen), var(--nav-bg);
    -webkit-backdrop-filter: blur(26px) saturate(180%);
    backdrop-filter: blur(26px) saturate(180%);
    border: 1px solid var(--nav-brd);
    box-shadow: var(--glass-rim);
    transform: translateY(-130%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.32s cubic-bezier(0.22, 1, 0.36, 1), opacity 0.32s ease;
  }
  .nav-links.open { transform: translateY(0); opacity: 1; pointer-events: auto; }
  .nav-links a {
    text-align: center;
    padding: 13px;
    border-bottom: 1px solid var(--line);
  }
  .nav-links a:last-child { border-bottom: none; }
  .nav-links a::after { display: none; }

  .section { padding: 48px 0; }
  .section-title { font-size: 1.5rem; }
}