/* ====================
   AI中转站 - 主样式文件
   科技感/AI风格设计
   ==================== */

/* CSS 变量定义 */
:root {
  /* ====================
     新配色（深色默认）
     黑底 + 高对比度 + 低视觉疲劳
     ==================== */
  --primary-color: #87E8DE; /* 主要按钮/链接：浅青 */
  --primary-dark: #5BCFC4;
  --secondary-color: #6B5BD6; /* 深紫：醒目但不刺眼 */
  --accent-warm: #F2C97D; /* 暖黄：强调但不紧急 */
  --danger-color: #E57373; /* 豆沙红：警示但不焦虑 */
  --success-color: #77D3A0; /* 墨绿偏柔和 */

  --primary-rgb: 135, 232, 222;
  --secondary-rgb: 107, 91, 214;
  --accent-warm-rgb: 242, 201, 125;
  --danger-rgb: 229, 115, 115;
  --success-rgb: 119, 211, 160;

  /* 渐变（装饰/强调） */
  --primary-gradient: linear-gradient(135deg, #87E8DE 0%, #2E7A73 100%);
  --brand-gradient: linear-gradient(135deg, #87E8DE 0%, #2E7A73 100%);

  /* 霓虹效果色（保持变量名，替换为更耐看的色系） */
  --neon-blue: var(--primary-color);
  --neon-purple: var(--secondary-color);
  --neon-green: var(--success-color);
  --neon-pink: var(--danger-color);

  /* 背景色 */
  --bg-dark: #0B0F14;
  --bg-darker: #070A0E;
  --bg-card: rgba(16, 22, 34, 0.86);
  --bg-card-hover: rgba(20, 28, 44, 0.92);

  /* 文字颜色（避免纯白刺眼） */
  --text-primary: #EAF0F8;
  --text-secondary: #B7C0CC;
  --text-muted: #8793A3;

  /* 边框 */
  --border-color: rgba(var(--primary-rgb), 0.18);
  --border-glow: rgba(var(--primary-rgb), 0.35);

  /* 阴影 */
  --shadow-neon: 0 0 22px rgba(var(--primary-rgb), 0.14);
  --shadow-card: 0 10px 32px rgba(0, 0, 0, 0.35);

  /* 按钮语义色（可按主题覆盖） */
  --btn-primary-bg: var(--primary-color);
  --btn-primary-fg: #061013;
  --btn-primary-shadow: 0 0 18px rgba(var(--primary-rgb), 0.18);
  --btn-primary-shadow-hover: 0 0 26px rgba(var(--primary-rgb), 0.26);
  --btn-tint-bg: rgba(var(--primary-rgb), 0.10);

  /* Toast foreground (theme aware) */
  --toast-fg: #061013;

  /* 间距 */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;

  /* 圆角 */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;

  /* 字体 */
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;

  /* 字体大小 - 默认中等 */
  --font-size-base: 16px;
}

/* 字体大小设置 */
html[data-font-size="small"] {
  --font-size-base: 14px;
}

html[data-font-size="medium"] {
  --font-size-base: 16px;
}

html[data-font-size="large"] {
  --font-size-base: 18px;
}

/* 浅色主题 */
html[data-theme="light"] {
  /* 浅色模式：低饱和 + 足够对比度 */
  --bg-dark: #F6F7FB;
  --bg-darker: #EEF1F6;
  --bg-card: rgba(255, 255, 255, 0.96);
  --bg-card-hover: rgba(248, 250, 252, 1);

  --text-primary: #111827;
  --text-secondary: #374151;
  --text-muted: #6B7280;

  --primary-color: #2E7A73;
  --primary-dark: #27665F;
  --primary-rgb: 46, 122, 115;

  --secondary-color: #5E54C7;
  --secondary-rgb: 94, 84, 199;

  --accent-warm: #C58B2B;
  --accent-warm-rgb: 197, 139, 43;

  --danger-color: #C35B5B;
  --danger-rgb: 195, 91, 91;

  --success-color: #2F8A63;
  --success-rgb: 47, 138, 99;

  --primary-gradient: linear-gradient(135deg, #2E7A73 0%, #1F6F69 100%);
  --brand-gradient: linear-gradient(135deg, #2E7A73 0%, #1F6F69 100%);

  --border-color: rgba(17, 24, 39, 0.10);
  --border-glow: rgba(var(--primary-rgb), 0.18);
  --shadow-card: 0 10px 30px rgba(15, 23, 42, 0.08);

  --btn-primary-bg: var(--primary-color);
  --btn-primary-fg: #F6F7FB;
  --btn-primary-shadow: 0 10px 24px rgba(var(--primary-rgb), 0.18);
  --btn-primary-shadow-hover: 0 14px 30px rgba(var(--primary-rgb), 0.22);
  --btn-tint-bg: rgba(var(--primary-rgb), 0.10);

  --toast-fg: #F6F7FB;
}

html[data-theme="light"] body::before {
  background-image:
    linear-gradient(rgba(var(--primary-rgb), 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(var(--primary-rgb), 0.04) 1px, transparent 1px);
}

html[data-theme="light"] .particles-bg {
  opacity: 0.3;
}

html[data-theme="light"] .navbar {
  background: rgba(255, 255, 255, 0.95);
  border-bottom: 1px solid rgba(17, 24, 39, 0.08);
}

html[data-theme="light"] .footer {
  background: rgba(255, 255, 255, 0.95);
  border-top: 1px solid rgba(17, 24, 39, 0.08);
}

/* 基础重置 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  overflow-x: hidden;
  width: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  background: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  width: 100%;
}

/* 防止移动端媒体/代码块撑破布局 */
img,
video,
iframe {
  max-width: 100%;
}

pre {
  max-width: 100%;
  overflow-x: auto;
}

/* 动态背景 - 科技网格 */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background:
    linear-gradient(90deg, rgba(var(--primary-rgb), 0.025) 1px, transparent 1px),
    linear-gradient(rgba(var(--primary-rgb), 0.025) 1px, transparent 1px);
  background-size: 50px 50px;
  pointer-events: none;
  z-index: -1;
}

/* 浮动粒子背景 */
.particles-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: -1;
  overflow: hidden;
}

.particle {
  position: absolute;
  width: 4px;
  height: 4px;
  background: var(--neon-blue);
  border-radius: 50%;
  opacity: 0.6;
  animation: float 15s infinite ease-in-out;
}

@keyframes float {
  0%, 100% { transform: translateY(100vh) rotate(0deg); opacity: 0; }
  10% { opacity: 0.6; }
  90% { opacity: 0.6; }
  100% { transform: translateY(-10vh) rotate(720deg); opacity: 0; }
}

/* ==================== 导航栏 ==================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 70px;
  background: rgba(7, 10, 14, 0.88);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--spacing-xl);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  min-width: 0;
}

.nav-logo .logo-icon {
  width: 40px;
  height: 40px;
  background: var(--brand-gradient);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  box-shadow: var(--shadow-neon);
}

.nav-logo span {
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  min-width: 0;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  list-style: none;
}

/* 移动端菜单专用（由 JS 克隆登录/注册按钮插入 nav-menu）
   桌面端隐藏，避免出现重复的登录/注册按钮 */
.nav-menu .mobile-nav-extra {
  display: none;
}

.nav-menu a {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  transition: all 0.3s ease;
  position: relative;
}

.nav-menu a:hover {
  color: var(--text-primary);
  background: var(--btn-tint-bg);
}

.nav-menu a.active {
  color: var(--primary-color);
}

.nav-menu a.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 2px;
  background: var(--brand-gradient);
  border-radius: 1px;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.3s ease;
  flex-shrink: 0;
}

.nav-toggle:hover {
  border-color: var(--primary-color);
  background: var(--btn-tint-bg);
}

.mobile-nav-overlay {
  display: none;
  position: fixed;
  top: 70px;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.45);
  backdrop-filter: blur(2px);
  z-index: 900;
}

.mobile-nav-overlay.open {
  display: block;
}

.fab-create-thread {
  position: fixed;
  right: 20px;
  bottom: var(--fab-bottom, 90px);
  bottom: calc(var(--fab-bottom, 90px) + env(safe-area-inset-bottom));
  width: 56px;
  height: 56px;
  border-radius: 9999px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: var(--brand-gradient);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 9998;
  box-shadow: 0 12px 35px rgba(0, 0, 0, 0.45), 0 0 26px rgba(var(--primary-rgb), 0.16);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  transition: transform 0.15s ease, box-shadow 0.2s ease, filter 0.2s ease;
}

.fab-layer {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100vh;
  pointer-events: none;
  z-index: 9998;
}

@supports (height: 100dvh) {
  .fab-layer {
    height: 100dvh;
  }
}

.fab-create-thread:hover {
  transform: translateY(-2px);
  filter: brightness(1.05);
  box-shadow: 0 14px 40px rgba(0, 0, 0, 0.55), 0 0 30px rgba(var(--primary-rgb), 0.20);
}

.fab-create-thread:active {
  transform: translateY(0);
  filter: brightness(0.98);
}

.fab-create-thread i {
  font-size: 1.25rem;
}

.fab-create-thread:focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px rgba(var(--primary-rgb), 0.22), 0 12px 35px rgba(0, 0, 0, 0.45);
}

.nav-search {
  position: relative;
}

.nav-search input {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-sm) var(--spacing-md);
  padding-left: 40px;
  color: var(--text-primary);
  width: 200px;
  transition: all 0.3s ease;
}

.nav-search input:focus {
  outline: none;
  border-color: var(--primary-color);
  width: 280px;
  box-shadow: var(--shadow-neon);
}

.nav-search input::placeholder {
  color: var(--text-muted);
}

.nav-search .search-icon {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
}

/* 搜索下拉框 */
.search-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  width: 320px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card), 0 0 26px rgba(var(--primary-rgb), 0.08);
  backdrop-filter: blur(10px);
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all 0.3s ease;
}

.search-dropdown.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.search-dropdown-content {
  padding: var(--spacing-md);
}

.search-section {
  margin-bottom: var(--spacing-md);
}

.search-section:last-child {
  margin-bottom: 0;
}

.search-section-title {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: var(--spacing-sm);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.search-section-title i {
  color: var(--neon-pink);
}

.search-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

.search-tag {
  display: inline-block;
  padding: 4px 10px;
  background: rgba(var(--primary-rgb), 0.10);
  border: 1px solid rgba(var(--primary-rgb), 0.20);
  border-radius: var(--radius-md);
  font-size: 0.8rem;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s ease;
}

.search-tag:hover {
  background: rgba(var(--primary-rgb), 0.16);
  color: var(--text-primary);
  border-color: var(--primary-color);
}

.search-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.search-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.2s ease;
}

.search-item:hover {
  background: rgba(var(--primary-rgb), 0.10);
}

.search-item i {
  color: var(--text-muted);
  font-size: 0.85rem;
}

.search-item span {
  font-size: 0.9rem;
  color: var(--text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.search-item:hover span {
  color: var(--text-primary);
}

/* 按钮样式 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.3s ease;
  border: none;
  text-decoration: none;
  white-space: nowrap;
  flex-shrink: 0;
}

.btn-primary {
  background: var(--btn-primary-bg);
  color: var(--btn-primary-fg);
  box-shadow: var(--btn-primary-shadow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--btn-primary-shadow-hover);
}

.btn-outline {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.btn-outline:hover {
  border-color: var(--primary-color);
  background: var(--btn-tint-bg);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
}

.btn-ghost:hover {
  color: var(--text-primary);
  background: var(--btn-tint-bg);
}

.btn-neon {
  background: transparent;
  border: 1px solid var(--neon-blue);
  color: var(--neon-blue);
  text-shadow: 0 0 10px var(--neon-blue);
  box-shadow: 0 0 10px rgba(var(--primary-rgb), 0.22);
}

.btn-neon:hover {
  background: var(--neon-blue);
  color: var(--bg-dark);
  box-shadow: 0 0 30px rgba(var(--primary-rgb), 0.28);
}

/* ==================== 用户下拉菜单 ==================== */
.user-dropdown {
  position: relative;
  display: inline-block;
}

.user-dropdown-btn {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.3s ease;
}

.user-dropdown-btn:hover {
  border-color: var(--primary-color);
  background: var(--btn-tint-bg);
}

.user-dropdown-btn .user-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--brand-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 600;
  color: white;
}

.user-dropdown-btn .user-name {
  font-weight: 500;
  max-width: 100px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.user-dropdown-btn .dropdown-arrow {
  font-size: 0.7rem;
  transition: transform 0.3s ease;
}

.user-dropdown.open .dropdown-arrow {
  transform: rotate(180deg);
}

.user-dropdown-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  min-width: 200px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all 0.3s ease;
  z-index: 1200;
  overflow: hidden;
}

.user-dropdown.open .user-dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.user-dropdown-header {
  padding: var(--spacing-md);
  border-bottom: 1px solid var(--border-color);
  background: rgba(255, 255, 255, 0.02);
}

.user-dropdown-header .user-email {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 2px;
}

.user-dropdown-header .user-role {
  display: inline-block;
  font-size: 0.7rem;
  padding: 2px 8px;
  background: var(--primary-gradient);
  border-radius: 10px;
  color: white;
  margin-top: var(--spacing-xs);
}

.user-dropdown-menu a,
.user-dropdown-menu button {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--text-secondary);
  text-decoration: none;
  background: none;
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
  font-size: 0.9rem;
  text-align: left;
}

.user-dropdown-menu a:hover,
.user-dropdown-menu button:hover {
  background: var(--btn-tint-bg);
  color: var(--text-primary);
}

.user-dropdown-menu a i,
.user-dropdown-menu button i {
  width: 18px;
  text-align: center;
  color: var(--text-muted);
}

.user-dropdown-menu a:hover i,
.user-dropdown-menu button:hover i {
  color: var(--primary-color);
}

.user-dropdown-divider {
  height: 1px;
  background: var(--border-color);
  margin: var(--spacing-xs) 0;
}

.user-dropdown-menu .logout-btn {
  color: var(--neon-pink);
}

.user-dropdown-menu .logout-btn:hover {
  background: rgba(var(--danger-rgb), 0.10);
}

.user-dropdown-menu .logout-btn i {
  color: var(--neon-pink);
}

/* 通知徽章 */
.notification-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 18px;
  height: 18px;
  padding: 0 5px;
  background: var(--neon-pink);
  color: white;
  font-size: 0.7rem;
  font-weight: 600;
  border-radius: 10px;
  margin-left: 6px;
}

/* 认证标记：显示认证中转站（enterprise=金色，personal=蓝色） */
.cert-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 12px;
  line-height: 1;
  font-weight: 600;
  text-decoration: none;
  white-space: nowrap;
  max-width: 100%;
  overflow: hidden;
  text-overflow: ellipsis;
  border: 1px solid transparent;
}

.cert-badge.enterprise {
  background: rgba(var(--accent-warm-rgb), 0.18);
  color: var(--accent-warm);
  border-color: rgba(var(--accent-warm-rgb), 0.35);
}

.cert-badge.personal {
  background: rgba(var(--primary-rgb), 0.14);
  color: var(--neon-blue);
  border-color: rgba(var(--primary-rgb), 0.30);
}

.cert-badge:hover {
  filter: brightness(1.1);
}

.user-dropdown-menu a .notification-badge {
  margin-left: auto;
}

/* ==================== 主内容区 ==================== */
.main-content {
  padding-top: 90px;
  min-height: 100vh;
}

.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--spacing-xl);
}

/* ==================== Hero 区域 ==================== */
.hero {
  padding: var(--spacing-2xl) 0;
  text-align: center;
  position: relative;
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 800;
  margin-bottom: var(--spacing-lg);
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--text-secondary) 45%, var(--primary-color) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: gradientShift 5s ease infinite;
}

@keyframes gradientShift {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto var(--spacing-xl);
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: var(--spacing-2xl);
  margin-top: var(--spacing-xl);
}

/* Public pages can opt-out of showing stats */
.no-public-stats .hero-stats,
.no-public-stats .quick-stats {
  display: none !important;
}

.stat-item {
  text-align: center;
}

.stat-number {
  font-size: 2.5rem;
  font-weight: 700;
  font-family: var(--font-mono);
  color: var(--neon-blue);
  text-shadow: 0 0 18px rgba(var(--primary-rgb), 0.28);
}

.stat-label {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: var(--spacing-xs);
}

/* 代码装饰效果 */
.code-decoration {
  position: absolute;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  opacity: 0.3;
  pointer-events: none;
}

.code-decoration.left {
  left: 10%;
  top: 20%;
}

.code-decoration.right {
  right: 10%;
  bottom: 20%;
}

/* ==================== 内容网格 ==================== */
.content-grid {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: var(--spacing-xl);
  padding: var(--spacing-xl) 0;
}

/* 主要内容区 */
.main-feed {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

/* 选项卡 */
.tabs {
  display: flex;
  gap: var(--spacing-xs);
  background: var(--bg-card);
  padding: var(--spacing-xs);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

.tab {
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.3s ease;
  font-weight: 500;
}

.tab:hover {
  color: var(--text-primary);
}

.tab.active {
  background: var(--primary-gradient);
  color: white;
}

/* ==================== 帖子卡片 ==================== */
.post-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: var(--spacing-lg);
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.post-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--brand-gradient);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.post-card:hover {
  border-color: var(--primary-color);
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
}

.post-card:hover::before {
  opacity: 1;
}

.post-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

.post-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--primary-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.post-meta {
  flex: 1;
}

.post-author {
  font-weight: 600;
  color: var(--text-primary);
}

.post-time {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.post-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
  cursor: pointer;
  transition: color 0.3s ease;
}

.post-title:hover {
  color: var(--primary-color);
}

.post-excerpt {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 12px;
  background: rgba(var(--primary-rgb), 0.10);
  border: 1px solid rgba(var(--primary-rgb), 0.20);
  border-radius: 20px;
  font-size: 0.8rem;
  color: var(--primary-color);
  transition: all 0.3s ease;
}

.tag:hover {
  background: rgba(var(--primary-rgb), 0.14);
}

.tag.ai-model {
  background: rgba(var(--primary-rgb), 0.12);
  border-color: rgba(var(--primary-rgb), 0.22);
  color: var(--neon-blue);
}

.tag.hot {
  background: rgba(var(--danger-rgb), 0.12);
  border-color: rgba(var(--danger-rgb), 0.22);
  color: var(--neon-pink);
}

.post-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--border-color);
}

.post-stats {
  display: flex;
  gap: var(--spacing-lg);
}

.post-stat {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  color: var(--text-muted);
  font-size: 0.9rem;
  cursor: pointer;
  transition: color 0.3s ease;
}

.post-stat:hover {
  color: var(--primary-color);
}

/* ==================== 侧边栏 ==================== */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.sidebar-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: var(--spacing-lg);
}

.sidebar-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.sidebar-title .icon {
  color: var(--primary-color);
}

/* AI 频道列表 */
.ai-channel-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.ai-channel-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md);
  background: rgba(255, 255, 255, 0.02);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.3s ease;
  text-decoration: none;
  color: inherit;
}

.ai-channel-item:hover {
  background: var(--btn-tint-bg);
  transform: translateX(4px);
}

.ai-channel-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  background: var(--primary-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
}

.ai-channel-info {
  flex: 1;
}

.ai-channel-name {
  font-weight: 600;
  font-size: 0.95rem;
}

.ai-channel-desc {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* 公告卡片 */
.announcement-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.announcement-item {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background 0.3s ease;
}

.announcement-item:hover {
  background: rgba(255, 255, 255, 0.03);
}

.announcement-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--neon-green);
  margin-top: 8px;
  flex-shrink: 0;
}

.announcement-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* 热门标签 */
.hot-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

/* ==================== 页脚 ==================== */
.footer {
  background: var(--bg-darker);
  border-top: 1px solid var(--border-color);
  padding: var(--spacing-2xl) 0;
  margin-top: var(--spacing-2xl);
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--spacing-xl);
}

.footer-brand {
  max-width: 300px;
}

.footer-brand .nav-logo {
  margin-bottom: var(--spacing-md);
}

.footer-brand p {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer-section h4 {
  color: var(--text-primary);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.3s ease;
}

.footer-links a:hover {
  color: var(--primary-color);
}

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-xl);
  margin-top: var(--spacing-xl);
  border-top: 1px solid var(--border-color);
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ==================== 响应式设计 ==================== */
@media (max-width: 1024px) {
  .content-grid {
    grid-template-columns: 1fr;
  }

  .sidebar {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-content {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .navbar {
    padding: 0 12px;
    overflow: visible;
    justify-content: flex-start;
    gap: 8px;
  }

  .container {
    padding: 0 var(--spacing-md);
  }

  .navbar .nav-logo {
    font-size: 1.05rem;
    flex: 0 0 auto;
    max-width: none;
  }

  .navbar .nav-logo .logo-icon {
    width: 32px;
    height: 32px;
    font-size: 1rem;
  }

  .navbar .nav-logo span {
    display: block;
    white-space: normal;
    word-break: normal;
    line-height: 1.05;
  }

  .nav-toggle {
    display: inline-flex;
    width: 36px;
    height: 36px;
  }

  .nav-menu {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: var(--spacing-xs);
    padding: var(--spacing-md);
    background: rgba(10, 10, 15, 0.98);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1001;
  }

  .nav-menu.open {
    display: flex;
  }

  .nav-menu li {
    width: 100%;
  }

  .nav-menu .mobile-nav-extra {
    display: block;
    width: 100%;
  }

  .nav-menu a {
    display: flex;
    align-items: center;
    width: 100%;
    justify-content: flex-start;
  }

  /* 移动端把搜索/登录注册收进菜单，避免顶部溢出 */
  .nav-actions > a.btn {
    display: none;
  }

  .nav-actions {
    gap: 8px;
    flex: 1 1 auto;
    min-width: 0;
    margin-left: 0;
    justify-content: flex-start;
  }

  .nav-search {
    flex: 1 1 auto;
    min-width: 0;
    max-width: none;
  }

  .nav-search input {
    width: 100%;
    padding: 8px 10px;
    padding-left: 34px;
    font-size: 0.9rem;
  }

  .nav-search input:focus {
    width: 100%;
  }

  .nav-search .search-icon {
    left: 10px;
  }

  .user-dropdown-btn {
    padding: 6px 10px;
  }

  .user-dropdown-btn .user-avatar {
    width: 26px;
    height: 26px;
  }

  .nav-actions .user-dropdown {
    margin-left: auto;
  }

  .search-dropdown {
    width: min(520px, calc(100vw - 32px));
  }

  .fab-create-thread {
    right: 16px;
    bottom: var(--fab-bottom, 86px);
    bottom: calc(var(--fab-bottom, 86px) + env(safe-area-inset-bottom));
    width: 52px;
    height: 52px;
    z-index: 9999;
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
    transform: translateZ(0);
    will-change: transform;
  }

  .fab-layer .fab-create-thread {
    position: absolute !important;
    right: 16px !important;
    bottom: var(--fab-bottom, 86px) !important;
    bottom: calc(var(--fab-bottom, 86px) + env(safe-area-inset-bottom)) !important;
    z-index: 9999 !important;
    pointer-events: auto !important;
  }

  .fab-layer {
    z-index: 9999;
  }

  .hero-title {
    font-size: 2.5rem;
  }

  .hero-stats {
    gap: var(--spacing-lg);
    flex-wrap: wrap;
    justify-content: center;
  }

  .stat-number {
    font-size: 2rem;
  }

  .sidebar {
    grid-template-columns: 1fr;
  }

  .footer-content {
    grid-template-columns: 1fr;
  }

  .code-decoration {
    display: none;
  }
}

@media (max-width: 576px) {
  .post-footer {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--spacing-sm);
  }

  .post-stats {
    flex-wrap: wrap;
    gap: var(--spacing-md);
  }

  .tabs {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }

  .tab {
    flex: 0 0 auto;
    padding: var(--spacing-sm) var(--spacing-md);
  }

  .user-dropdown-btn .user-name {
    display: none;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 2rem;
  }

  .hero-subtitle {
    font-size: 1rem;
  }
}

/* ==================== 动画效果 ==================== */
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

@keyframes glow {
  0%, 100% { box-shadow: 0 0 5px var(--neon-blue); }
  50% { box-shadow: 0 0 20px var(--neon-blue), 0 0 30px var(--neon-blue); }
}

.animate-pulse {
  animation: pulse 2s infinite;
}

.animate-glow {
  animation: glow 2s infinite;
}

/* 打字机效果 */
.typewriter {
  overflow: hidden;
  border-right: 2px solid var(--neon-blue);
  white-space: nowrap;
  animation: typing 3.5s steps(40, end), blink-caret 0.75s step-end infinite;
}

@keyframes typing {
  from { width: 0 }
  to { width: 100% }
}

@keyframes blink-caret {
  from, to { border-color: transparent }
  50% { border-color: var(--neon-blue); }
}

/* 滚动条样式（仅桌面端显示，移动端会挡交互） */
@media (min-width: 769px) {
  ::-webkit-scrollbar {
    width: 8px;
    height: 8px;
  }

  ::-webkit-scrollbar-track {
    background: var(--bg-darker);
  }

  ::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
  }

  ::-webkit-scrollbar-thumb:hover {
    background: var(--primary-color);
  }
}

/* 移动端隐藏滚动条（避免右侧“进度条”遮挡） */
@media (max-width: 768px) {
  html, body {
    scrollbar-width: none;
    -ms-overflow-style: none;
  }

  ::-webkit-scrollbar {
    width: 0 !important;
    height: 0 !important;
  }
}

/* 选中文本样式 */
::selection {
  background: var(--primary-color);
  color: var(--btn-primary-fg);
}

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

.text-neon {
  color: var(--neon-blue);
  text-shadow: 0 0 10px var(--neon-blue);
}

.glass {
  background: rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(10px);
}

.border-glow {
  border: 1px solid var(--border-glow);
  box-shadow: 0 0 15px rgba(var(--primary-rgb), 0.18);
}

/* ==================== 反馈建议弹窗 ==================== */
.feedback-modal {
  position: fixed;
  inset: 0;
  z-index: 9998;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 24px;
}

.feedback-modal.active {
  display: flex;
}

.feedback-overlay {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.55);
  backdrop-filter: blur(8px);
}

.feedback-dialog {
  position: relative;
  width: min(560px, calc(100vw - 32px));
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
  overflow: hidden;
}

.feedback-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-lg);
  border-bottom: 1px solid var(--border-color);
  gap: var(--spacing-md);
}

.feedback-header h3 {
  margin: 0;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 10px;
}

.feedback-close {
  width: 38px;
  height: 38px;
  border-radius: 12px;
  border: 1px solid var(--border-color);
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}

.feedback-close:hover {
  color: var(--text-primary);
  border-color: rgba(var(--primary-rgb), 0.55);
  background: rgba(var(--primary-rgb), 0.08);
}

.feedback-body {
  padding: var(--spacing-lg);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.feedback-textarea {
  width: 100%;
  min-height: 140px;
  resize: vertical;
  background: var(--bg-darker);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
  color: var(--text-primary);
  outline: none;
  line-height: 1.6;
}

.feedback-textarea:focus {
  border-color: rgba(var(--primary-rgb), 0.75);
  box-shadow: 0 0 0 4px rgba(var(--primary-rgb), 0.12);
}

.feedback-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.feedback-footer {
  padding: var(--spacing-lg);
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: flex-end;
  gap: var(--spacing-sm);
}

.legal-scroll {
  max-height: min(62vh, 520px);
  overflow-y: auto;
  padding: 14px 16px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  background: var(--bg-darker);
  color: var(--text-secondary);
  line-height: 1.75;
}

.legal-scroll h4 {
  margin: 12px 0 8px 0;
  color: var(--text-primary);
  font-size: 1rem;
}

.legal-scroll h4:first-child {
  margin-top: 0;
}

.legal-scroll p {
  margin: 8px 0;
}

.legal-scroll ul {
  margin: 8px 0 8px 18px;
}

.legal-scroll li {
  margin: 6px 0;
}

.legal-scroll .legal-muted {
  color: var(--text-muted);
  font-size: 0.9rem;
}