/* ============================================================
   Modern Layout System - 现代化悬浮导航系统
   支持：侧边、顶部、底部、窄边、悬浮自动隐藏
   ============================================================ */

:root {
  --nav-width: 240px;
  --nav-slim-width: 64px;
  --nav-height: 60px;
  --nav-bg: rgba(15, 23, 42, 0.85);
  --nav-hover-bg: rgba(255, 255, 255, 0.08);
  --nav-active-bg: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
  --nav-text: rgba(255, 255, 255, 0.7);
  --nav-text-active: #ffffff;
  --nav-border: rgba(255, 255, 255, 0.1);
  --floating-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  --backdrop-blur: blur(20px);
  --transition-smooth: cubic-bezier(0.16, 1, 0.3, 1);
}

body {
  margin: 0;
  overflow: hidden;
  background-color: var(--g50);
}

/* ============================================================
   侧边栏导航 (Sidebar)
   ============================================================ */

.sidebar {
  position: fixed;
  z-index: 1000;
  left: 12px;
  top: 12px;
  bottom: 12px;
  width: var(--nav-slim-width);
  background: var(--nav-bg);
  backdrop-filter: var(--backdrop-blur);
  -webkit-backdrop-filter: var(--backdrop-blur);
  box-shadow: var(--floating-shadow);
  border-radius: 20px;
  border: 1px solid var(--nav-border);
  display: flex;
  flex-direction: column;
  transition: width 0.4s var(--transition-smooth), transform 0.4s var(--transition-smooth);
  overflow: hidden;
}

/* 展开状态 */
.sidebar:hover, .sidebar.expanded {
  width: var(--nav-width);
}

.sidebar.hidden {
  transform: translateX(calc(-100% - 24px));
}

.edge-trigger-left {
  position: fixed;
  left: 0;
  top: 0;
  bottom: 0;
  width: 12px;
  z-index: 999;
}

.nav-header {
  padding: 16px;
  height: 64px;
  display: flex;
  align-items: center;
  overflow: hidden;
  border-bottom: 1px solid var(--nav-border);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  white-space: nowrap;
}

.nav-logo-icon {
  width: 32px;
  height: 32px;
  background: var(--nav-active-bg);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
  flex-shrink: 0;
}

.nav-logo-text {
  font-size: 18px;
  font-weight: 800;
  color: var(--nav-text-active);
  letter-spacing: -0.5px;
  opacity: 0;
  transform: translateX(-10px);
  transition: all 0.3s var(--transition-smooth);
}

.sidebar:hover .nav-logo-text, .sidebar.expanded .nav-logo-text {
  opacity: 1;
  transform: translateX(0);
}

/* 后台播放指示器 */
.bg-audio-wave {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 2px;
  height: 12px;
  padding-right: 8px;
}
.bg-audio-wave span {
  width: 2px;
  background: var(--accent);
  border-radius: 1px;
  animation: wave 1s infinite ease-in-out;
}
.bg-audio-wave span:nth-child(2) { animation-delay: 0.2s; }
.bg-audio-wave span:nth-child(3) { animation-delay: 0.4s; }

@keyframes wave {
  0%, 100% { height: 4px; }
  50% { height: 12px; }
}

.nav-body {
  flex: 1;
  padding: 12px 8px;
  overflow-y: auto;
  overflow-x: hidden;
}

.nav-body::-webkit-scrollbar { width: 0; }

.nav-group {
  margin-bottom: 20px;
}

.nav-group-title {
  font-size: 10px;
  font-weight: 700;
  color: var(--g500);
  text-transform: uppercase;
  margin-left: 12px;
  margin-bottom: 8px;
  white-space: nowrap;
  opacity: 0;
  transition: opacity 0.3s;
}

.sidebar:hover .nav-group-title, .sidebar.expanded .nav-group-title {
  opacity: 1;
}

.nav-item {
  display: flex;
  align-items: center;
  height: 48px;
  padding: 0 14px;
  margin-bottom: 4px;
  border-radius: 14px;
  color: var(--nav-text);
  text-decoration: none;
  border: none;
  background: transparent;
  width: 100%;
  cursor: pointer;
  transition: all 0.2s var(--transition-smooth);
  position: relative;
}

.nav-item-icon {
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  flex-shrink: 0;
}

.nav-item-text {
  margin-left: 12px;
  font-size: 14px;
  font-weight: 600;
  white-space: nowrap;
  opacity: 0;
  transform: translateX(-10px);
  transition: all 0.3s var(--transition-smooth);
}

.sidebar:hover .nav-item-text, .sidebar.expanded .nav-item-text {
  opacity: 1;
  transform: translateX(0);
}

.nav-item:hover {
  background: var(--nav-hover-bg);
  color: var(--nav-text-active);
}

.nav-item.active {
  background: var(--nav-active-bg);
  color: white;
  box-shadow: 0 4px 15px rgba(59, 130, 246, 0.25);
}

.nav-footer {
  padding: 16px;
  border-top: 1px solid var(--nav-border);
}

/* ============================================================
   底部导航 (Mobile Bottom Nav)
   ============================================================ */

.mobile-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: 64px;
  background: var(--nav-bg);
  backdrop-filter: var(--backdrop-blur);
  -webkit-backdrop-filter: var(--backdrop-blur);
  box-shadow: 0 -8px 32px rgba(0, 0, 0, 0.2);
  display: none;
  justify-content: space-around;
  align-items: center;
  z-index: 1000;
  border-top: 1px solid var(--nav-border);
  padding-bottom: env(safe-area-inset-bottom);
}

.mobile-nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  color: var(--nav-text);
  text-decoration: none;
  background: none;
  border: none;
  padding: 8px;
  font-size: 10px;
  font-weight: 600;
  flex: 1;
}

.mobile-nav-item.active {
  color: #3b82f6;
}

.mobile-nav-icon {
  font-size: 20px;
}

/* ============================================================
   主容器
   ============================================================ */

.app-container {
  position: fixed;
  inset: 0;
  display: flex;
}

.app-main {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding-left: calc(var(--nav-slim-width) + 24px);
  padding-right: 24px;
  padding-top: 24px;
  padding-bottom: 24px;
  transition: padding 0.4s var(--transition-smooth);
}

.sidebar.hidden ~ .app-main,
body:has(.sidebar.hidden) .app-main {
  padding-left: 24px;
}

/* ============================================================
   沉浸模式 (Immersive Mode)
   ============================================================ */

body.immersive-mode .mobile-nav {
  display: none !important;
}

body.immersive-mode .app-main {
  padding-left: 24px !important;
  padding-right: 24px !important;
  max-width: 900px;
  margin: 0 auto;
}

body.immersive-mode .sidebar {
  transform: translateX(calc(-100% - 24px));
}
  padding-top: 24px;
  padding-bottom: 24px;
  transition: padding 0.4s var(--transition-smooth);
}

/* ============================================================
   响应式调整
   ============================================================ */

@media (max-width: 768px) {
  .sidebar {
    display: none;
  }
  
  .mobile-nav {
    display: flex;
  }
  
  .app-main {
    padding-left: 16px;
    padding-right: 16px;
    padding-bottom: 84px; /* 为底部菜单留空 */
  }
  
  .nav-toggle-btn {
    display: none;
  }
}

/* 顶部/自动隐藏逻辑 (由 JS 控制) */
.sidebar.auto-hide {
  transform: translateX(-100%);
}
.sidebar.auto-hide:hover {
  transform: translateX(0);
}

.edge-trigger-left {
  position: fixed;
  left: 0;
  top: 0;
  bottom: 0;
  width: 12px;
  z-index: 999;
}