/* =========================================
   Skype 官网 - 全局样式（导航栏 + 页脚）
   ========================================= */

/* --- CSS 变量 --- */
:root {
  --skype-primary: #0078D4;
  --skype-primary-hover: #106EBE;
  --skype-text: #1F1F1F;
  --skype-text-secondary: #5F6368;
  --skype-border: #E5E7EB;
  --skype-bg: #FFFFFF;
  --skype-shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
  --skype-shadow-md: 0 8px 24px rgba(0, 0, 0, 0.1);
  --skype-transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==========================================
   1. 导航栏容器
   ========================================== */
.skype-header {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
  position: sticky;
  top: 0;
  z-index: 1000;
  width: 100%;
  height: 68px;
  transition: var(--skype-transition);
}

.skype-header.scrolled {
  box-shadow: var(--skype-shadow-md);
  background: rgba(255, 255, 255, 0.98);
  height: 60px;
}

/* ==========================================
   2. 导航栏内部容器
   ========================================== */
.skype-header-inner {
  max-width: 1280px;
  height: 100%;
  margin: 0 auto;
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: relative;
}

/* ==========================================
   3. Logo - 纯文字
   ========================================== */
.skype-logo {
  font-size: 24px;
  font-weight: 700;
  font-family: "Segoe UI", "Google Sans", "Inter", -apple-system, sans-serif;
  letter-spacing: -0.5px;
  text-decoration: none;
  white-space: nowrap;
  flex-shrink: 0;
  z-index: 2;
  
  /* 蓝色渐变 */
  background: linear-gradient(135deg, #0078D4 0%, #00A4EF 50%, #0078D4 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  
  /* 发光 */
  filter: drop-shadow(0 0 6px rgba(0, 120, 212, 0.3));
  transition: filter 0.3s ease, opacity 0.25s ease;
}

.skype-logo:hover {
  filter: drop-shadow(0 0 14px rgba(0, 120, 212, 0.5));
  opacity: 0.9;
}

/* ==========================================
   4. 导航菜单 - 居中
   ========================================== */
.skype-nav {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  z-index: 1;
}

.skype-menu {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.skype-menu li {
  margin: 0;
  padding: 0;
}

.skype-menu a {
  display: flex;
  align-items: center;
  padding: 0 16px;
  height: 68px;
  font-size: 15px;
  font-weight: 500;
  color: #1F1F1F;
  text-decoration: none;
  white-space: nowrap;
  position: relative;
  transition: color 0.2s ease;
}

.skype-menu a:hover {
  color: #0078D4;
}

/* 当前菜单项 */
.skype-menu .current-menu-item > a {
  color: #0078D4;
  font-weight: 600;
}

/* 下划线动画 */
.skype-menu a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 16px;
  right: 16px;
  height: 2px;
  background: #0078D4;
  border-radius: 2px 2px 0 0;
  transform: scaleX(0);
  transition: transform 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

.skype-menu a:hover::after,
.skype-menu .current-menu-item > a::after {
  transform: scaleX(1);
}

/* ==========================================
   5. 右侧下载按钮
   ========================================== */
.skype-header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
  z-index: 2;
}

.skype-btn-download {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  background: #0078D4;
  color: #FFFFFF;
  font-size: 14px;
  font-weight: 600;
  border-radius: 8px;
  text-decoration: none;
  transition: var(--skype-transition);
  box-shadow: 0 2px 8px rgba(0, 120, 212, 0.25);
  white-space: nowrap;
  border: 2px solid transparent;
}

.skype-btn-download:hover {
  background: #106EBE;
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(0, 120, 212, 0.4);
}

.skype-btn-download svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

/* ==========================================
   6. 移动端菜单按钮
   ========================================== */
.skype-menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 10px;
  border: 1px solid #E5E7EB;
  background: #FFFFFF;
  color: #1F1F1F;
  cursor: pointer;
  transition: var(--skype-transition);
  padding: 0;
  flex-shrink: 0;
  z-index: 2;
}

.skype-menu-toggle:hover {
  background: rgba(0, 120, 212, 0.04);
  border-color: #0078D4;
}

.skype-menu-toggle svg {
  width: 22px;
  height: 22px;
}

/* ==========================================
   7. 响应式设计
   ========================================== */

/* Tablet (≤1024px) */
@media screen and (max-width: 1024px) {
  .skype-header {
    height: 60px;
  }

  .skype-header-inner {
    padding: 0 24px;
  }

  /* 取消居中，改回正常流 */
  .skype-nav {
    position: static;
    transform: none;
    display: none;
  }

  .skype-nav.open {
    display: block;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: #FFFFFF;
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
    box-shadow: var(--skype-shadow-md);
    padding: 16px 24px;
    z-index: 1000;
  }

  .skype-menu {
    flex-direction: column;
    gap: 4px;
  }

  .skype-menu a {
    height: auto;
    padding: 14px 16px;
    border-radius: 10px;
  }

  .skype-menu a::after {
    display: none;
  }

  .skype-menu a:hover {
    background: rgba(0, 120, 212, 0.04);
  }

  /* 显示汉堡菜单 */
  .skype-menu-toggle {
    display: flex;
  }

  /* Logo 缩小 */
  .skype-logo {
    font-size: 20px;
  }
}

/* Mobile (≤768px) */
@media screen and (max-width: 768px) {
  .skype-header {
    height: 56px;
  }

  .skype-header.scrolled {
    height: 50px;
  }

  .skype-header-inner {
    padding: 0 16px;
  }

  .skype-nav.open {
    top: 56px;
  }

  .skype-logo {
    font-size: 18px;
  }

  .skype-btn-download {
    padding: 8px 14px;
    font-size: 13px;
  }
}

/* Small Mobile (≤480px) */
@media screen and (max-width: 480px) {
  .skype-logo {
    font-size: 16px;
  }

  .skype-btn-download {
    padding: 8px 12px;
    font-size: 12px;
  }
}

/* ==========================================
   8. 页脚样式
   ========================================== */
.site-footer,
#colophon {
  background: #F8F9FA;
  border-top: 1px solid #E5E7EB;
  padding: 40px 0;
}

.site-footer .ast-container,
#colophon .ast-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 32px;
}

.site-footer a,
#colophon a {
  color: #5F6368;
  text-decoration: none;
  transition: color 0.2s ease;
}

.site-footer a:hover,
#colophon a:hover {
  color: #0078D4;
}

@media screen and (max-width: 768px) {
  .site-footer .ast-container,
  #colophon .ast-container {
    padding: 0 16px;
  }
}

/* ==========================================
   9. 打印样式
   ========================================== */
@media print {
  .skype-header {
    position: static !important;
    box-shadow: none !important;
  }
  
  .skype-btn-download,
  .skype-menu-toggle {
    display: none !important;
  }
}