/*
 * layout.css
 * 作用：定义网站的整体布局结构：容器、网格、导航栏、页脚、移动端菜单
 */

/* ===== 通用容器 ===== */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-md);
  padding-right: var(--space-md);
}

/* ===== 区块间距 ===== */
.section {
  padding-top: var(--space-xl);
  padding-bottom: var(--space-xl);
}

.section-sm {
  padding-top: var(--space-lg);
  padding-bottom: var(--space-lg);
}

.section-title {
  text-align: center;
  margin-bottom: var(--space-lg);
}

.section-title h2 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-xs);
}

.section-title p {
  color: var(--text-secondary);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* ===== 12 栏网格系统 ===== */
.row {
  display: flex;
  flex-wrap: wrap;
  margin-left: calc(var(--space-md) * -0.5);
  margin-right: calc(var(--space-md) * -0.5);
}

.col {
  flex: 1 0 0%;
  padding-left: calc(var(--space-md) * 0.5);
  padding-right: calc(var(--space-md) * 0.5);
}

.col-3 { flex: 0 0 25%; max-width: 25%; }
.col-4 { flex: 0 0 33.333333%; max-width: 33.333333%; }
.col-6 { flex: 0 0 50%; max-width: 50%; }
.col-8 { flex: 0 0 66.666667%; max-width: 66.666667%; }
.col-12 { flex: 0 0 100%; max-width: 100%; }

/* 响应式：平板和手机全部变 12 栏 */
@media (max-width: 992px) {
  .col-3,
  .col-4,
  .col-6,
  .col-8 {
    flex: 0 0 100%;
    max-width: 100%;
  }

  .section-title h2 {
    font-size: 1.75rem;
  }
}

/* ===== 顶部导航栏 ===== */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--navbar-bg);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--navbar-border);
  transition: background-color 0.3s ease, border-color 0.3s ease;
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.navbar-brand img {
  height: 40px;
  width: auto;
  display: block;
}

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

.navbar-nav a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 0.5rem 0;
  position: relative;
  transition: color 0.2s ease;
}

.navbar-nav a:hover,
.navbar-nav a.active {
  color: var(--color-primary);
}

.navbar-nav a::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width 0.2s ease;
}

.navbar-nav a:hover::after,
.navbar-nav a.active::after {
  width: 100%;
}

.navbar-actions {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.icon-btn {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  background: var(--bg-secondary);
  transition: background-color 0.2s ease, color 0.2s ease;
}

.icon-btn:hover {
  background: var(--color-primary);
  color: #fff;
}

.icon-btn svg {
  width: 20px;
  height: 20px;
}

/* 汉堡菜单按钮：只在手机显示 */
.navbar-toggle {
  display: none;
}

/* ===== 移动端菜单 ===== */
@media (max-width: 768px) {
  .navbar-nav {
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    bottom: 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    background: var(--bg-primary);
    padding: var(--space-md);
    transform: translateX(-100%);
    transition: transform 0.3s ease;
  }

  .navbar-nav.open {
    transform: translateX(0);
  }

  .navbar-nav a {
    width: 100%;
    padding: var(--space-sm) 0;
    border-bottom: 1px solid var(--card-border);
  }

  .navbar-nav a::after {
    display: none;
  }

  .navbar-toggle {
    display: flex;
  }

  .navbar-actions {
    margin-left: auto;
    margin-right: var(--space-sm);
  }
}

/* ===== 页脚 ===== */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--card-border);
  padding-top: var(--space-xl);
  padding-bottom: var(--space-lg);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-lg);
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.footer-brand img {
  height: 32px;
  width: auto;
  display: block;
}

.footer-desc {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.7;
}

.footer-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.footer-links li {
  margin-bottom: var(--space-xs);
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  transition: color 0.2s ease;
}

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

.footer-contact li {
  display: flex;
  align-items: flex-start;
  gap: var(--space-xs);
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: var(--space-xs);
}

.footer-contact svg {
  width: 18px;
  height: 18px;
  color: var(--color-primary);
  flex-shrink: 0;
  margin-top: 3px;
}

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

@media (max-width: 992px) {
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 576px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

/* ===== 页面顶部大图/标题区 ===== */
.page-header {
  background: var(--bg-hero);
  color: var(--text-on-dark);
  padding-top: var(--space-2xl);
  padding-bottom: var(--space-xl);
  text-align: center;
}

.page-header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: var(--space-xs);
}

.page-header p {
  font-size: 1.125rem;
  color: rgba(248, 250, 252, 0.8);
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
}

@media (max-width: 768px) {
  .page-header h1 {
    font-size: 1.875rem;
  }
}