/* ==========================================================================
   上海识记教育科技有限公司 - 企业官网核心设计系统样式表
   ========================================================================== */

/* 1. 现代企业美学变量 */
:root {
  --color-primary: #4CBBA9;      /* 妙记单词 App 主题色：清新教育科技绿，温和科学 */
  --color-primary-hover: #3da393;
  --color-secondary: #1e3a8a;    /* 经典企业深蓝色，象征学术底蕴与严谨科技实力 */
  --color-secondary-hover: #1e40af;
  
  --color-dark: #0f172a;         /* 深灰色，用作主标题与文本，极具质感 */
  --color-gray: #475569;         /* 灰蓝色，用作正文说明 */
  --color-light: #f8fafc;        /* 极浅灰蓝色，用作交错板块背景 */
  --color-white: #ffffff;        /* 纯白色背景 */
  --color-border: #e2e8f0;       /* 细致雅观的边框线 */
  
  --font-corporate: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  --transition-smooth: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.08);
  --shadow-md: 0 4px 6px -1px rgba(15, 23, 42, 0.08), 0 2px 4px -1px rgba(15, 23, 42, 0.04);
  --shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, 0.08), 0 4px 6px -2px rgba(15, 23, 42, 0.04);
}

/* 2. 重置与通用设置 */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-corporate);
  background-color: var(--color-white);
  color: var(--color-gray);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--color-dark);
  font-weight: 700;
  line-height: 1.3;
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition-smooth);
}

ul {
  list-style: none;
}

/* 全局布局辅助类 */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.section {
  padding: 6rem 0;
}

.section-alt {
  background-color: var(--color-light);
}

/* 精准正规标题排版 */
.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 4rem auto;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--color-dark);
  margin-bottom: 1rem;
  position: relative;
  display: inline-block;
  padding-bottom: 0.75rem;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 50px;
  height: 3px;
  background-color: var(--color-secondary);
  border-radius: 2px;
}

.section-subtitle {
  font-size: 1.1rem;
  color: var(--color-gray);
  line-height: 1.6;
}

/* 3. 经典稳重头部导航栏 */
.header-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 80px;
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
  transition: var(--transition-smooth);
}

.header-nav.scrolled {
  box-shadow: var(--shadow-md);
  height: 70px;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 100%;
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.logo-icon {
  width: 38px;
  height: 38px;
  background-color: var(--color-primary);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-white);
  font-weight: 800;
  font-size: 1.25rem;
}

.logo-text {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-dark);
  letter-spacing: 0.5px;
}

.logo-sub {
  font-size: 0.7rem;
  color: var(--color-gray);
  font-weight: 400;
  display: block;
  letter-spacing: 1px;
}

.menu-list {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.menu-item a {
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-gray);
  padding: 0.5rem 0;
  position: relative;
}

.menu-item a:hover, .menu-item.active a {
  color: var(--color-primary);
}

.menu-item a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-primary);
  transition: var(--transition-smooth);
}

.menu-item a:hover::after, .menu-item.active a::after {
  width: 100%;
}

/* 移动端菜单切换按钮 */
.menu-toggle-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.menu-toggle-btn span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-dark);
  margin-bottom: 5px;
  transition: var(--transition-smooth);
}

.menu-toggle-btn span:last-child {
  margin-bottom: 0;
}

/* 4. 经典大气企业内页 Banner */
.page-banner {
  padding: 9rem 0 5rem 0;
  background: linear-gradient(135deg, #1e3a8a 0%, #0f172a 100%);
  color: var(--color-white);
  position: relative;
  overflow: hidden;
}

.page-banner-content h1 {
  font-size: 2.75rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 1rem;
}

.page-banner-content p {
  font-size: 1.15rem;
  opacity: 0.85;
  max-width: 600px;
}

.breadcrumb {
  margin-top: 1.5rem;
  font-size: 0.9rem;
  opacity: 0.7;
}

.breadcrumb a:hover {
  text-decoration: underline;
}

/* 5. 经典高级按钮系统 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 2rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: 6px;
  cursor: pointer;
  transition: var(--transition-smooth);
}

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

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

.btn-secondary {
  background-color: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-secondary:hover {
  background-color: var(--color-primary);
  color: var(--color-white);
  transform: translateY(-2px);
}

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

.btn-white:hover {
  background-color: var(--color-light);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* 6. 通用页脚系统 */
.footer-corporate {
  background-color: #0f172a;
  color: #94a3b8;
  padding: 5rem 0 2.5rem 0;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  font-size: 0.9rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.5fr;
  gap: 4rem;
  margin-bottom: 4rem;
}

.footer-brand h3 {
  color: var(--color-white);
  font-size: 1.25rem;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.footer-brand-desc {
  line-height: 1.6;
  margin-bottom: 1.5rem;
}

.footer-links h4, .footer-contact h4 {
  color: var(--color-white);
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  position: relative;
  padding-bottom: 0.5rem;
}

.footer-links h4::after, .footer-contact h4::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 30px;
  height: 2px;
  background-color: var(--color-primary);
}

.footer-links-list li {
  margin-bottom: 0.8rem;
}

.footer-links-list a:hover {
  color: var(--color-white);
  padding-left: 4px;
}

.footer-contact-list li {
  margin-bottom: 0.8rem;
  display: flex;
  gap: 0.5rem;
  align-items: flex-start;
}

.footer-contact-list svg {
  flex-shrink: 0;
  margin-top: 0.25rem;
  color: var(--color-primary);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.back-to-top {
  width: 40px;
  height: 40px;
  border-radius: 6px;
  background-color: rgba(255, 255, 255, 0.05);
  color: var(--color-white);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-smooth);
}

.back-to-top:hover {
  background-color: var(--color-primary);
}

/* 7. 页面专项卡片与排版组件 */

/* 卡片浮起过渡效果 */
.hover-card {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 2.25rem;
  transition: var(--transition-smooth);
  box-shadow: var(--shadow-sm);
}

.hover-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-border);
}

/* 双栏图文交错排版 */
.split-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

.split-image-box {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-border);
}

.split-image-box img {
  display: block;
  width: 100%;
}

/* 全局动画控制 */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* 8. 响应式布局媒体查询 */
@media (max-width: 1024px) {
  .footer-grid {
    grid-template-columns: 1.2fr 0.8fr 0.8fr 1.2fr;
    gap: 2.5rem;
  }
  .split-layout {
    gap: 3rem;
  }
}

@media (max-width: 768px) {
  body {
    font-size: 15px;
  }
  .section {
    padding: 4rem 0;
  }
  .header-nav {
    height: 70px;
  }
  .menu-toggle-btn {
    display: block;
  }
  .menu-list {
    position: fixed;
    top: 70px;
    left: 0;
    width: 100%;
    background-color: var(--color-white);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: 1.5rem 0;
    gap: 1.5rem;
    box-shadow: var(--shadow-lg);
    transform: translateY(-120%);
    opacity: 0;
    transition: var(--transition-smooth);
    pointer-events: none;
  }
  .menu-list.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }
  .split-layout {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }
  .footer-bottom {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }
}