/* ============================================
   万星轮胎官网 - 布局样式
   ============================================ */

/* ========== 导航栏 ========== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: linear-gradient(120deg, rgba(21, 101, 192, 0.95), rgba(38, 50, 56, 0.95));
  backdrop-filter: blur(18px);
  box-shadow: var(--box-shadow-md);
  z-index: 1000;
  transition: transform var(--transition-base), box-shadow var(--transition-base), background var(--transition-base);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.header::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 6px;
  background: repeating-linear-gradient(
    90deg,
    rgba(255, 255, 255, 0.28) 0 18px,
    rgba(255, 255, 255, 0) 18px 36px
  );
  opacity: 0.35;
}

.header.scrolled {
  box-shadow: var(--box-shadow-lg);
  transform: translateY(-2px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  padding: 0 var(--space-xl);
  margin: 0 auto;
  max-width: calc(var(--max-container-width) + var(--space-xl));
}

/* ========== Logo ========== */
.logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-white);
  letter-spacing: 0.04em;
  transition: transform var(--transition-fast), color var(--transition-fast);
}

.logo:hover {
  transform: translateY(-2px);
  color: var(--color-secondary);
}

.logo-text {
  display: flex;
  flex-direction: column;
  line-height: 1;
}

.logo-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
}

.logo-tagline {
  margin-top: 2px;
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.6);
}

.logo-icon {
  width: 44px;
  height: 44px;
  background:
    radial-gradient(circle at 20% 20%, rgba(255, 255, 255, 0.45), transparent 55%),
    linear-gradient(135deg, var(--color-primary-light), var(--color-secondary));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-white);
  font-weight: var(--font-weight-bold);
  font-size: var(--font-size-lg);
  box-shadow: inset 0 0 0 2px rgba(255, 255, 255, 0.25);
}

/* ========== 导航菜单 ========== */
.nav {
  display: flex;
  align-items: center;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: var(--space-sm);
  align-items: center;
  margin: 0;
  padding: 0;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: block;
  padding: calc(var(--space-sm) + 4px) var(--space-lg);
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  letter-spacing: 0.02em;
  transition: color var(--transition-fast), transform var(--transition-fast);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 6px;
  left: var(--space-lg);
  right: var(--space-lg);
  height: 3px;
  background: linear-gradient(90deg, var(--color-secondary), var(--color-primary-light));
  transform: scaleX(0);
  transform-origin: center;
  transition: transform var(--transition-fast);
  border-radius: var(--border-radius-full);
}

.nav-link:hover,
.nav-link:focus {
  color: var(--color-text-white);
  transform: translateY(-2px);
}

.nav-link:hover::after,
.nav-link:focus::after,
.nav-link.active::after {
  transform: scaleX(1);
}

.nav-link.active {
  color: var(--color-text-white);
}

/* ========== 二级下拉菜单 ========== */
.nav-submenu {
  position: absolute;
  top: calc(100% + 12px);
  left: 0;
  background-color: var(--color-background-light);
  min-width: 220px;
  list-style: none;
  box-shadow: var(--box-shadow-lg);
  border-radius: var(--border-radius-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-12px);
  transition: all var(--transition-fast);
  margin-top: 0;
  overflow: hidden;
  border: 1px solid rgba(21, 101, 192, 0.1);
}

.nav-item:hover .nav-submenu,
.nav-item:focus-within .nav-submenu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.nav-submenu li {
  margin: 0;
}

.nav-submenu a {
  display: block;
  padding: var(--space-md) var(--space-xl);
  color: var(--color-text-dark);
  text-decoration: none;
  transition: all var(--transition-fast);
  border-left: 4px solid transparent;
  font-weight: var(--font-weight-medium);
}

.nav-submenu a:hover,
.nav-submenu a:focus {
  background: linear-gradient(90deg, rgba(21, 101, 192, 0.08), rgba(21, 101, 192, 0));
  color: var(--color-primary-main);
  border-left-color: var(--color-secondary);
  padding-left: calc(var(--space-xl) + 6px);
}

/* ========== 移动端菜单按钮 ========== */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 6px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.menu-toggle span {
  width: 28px;
  height: 3px;
  background-color: var(--color-text-white);
  border-radius: var(--border-radius-sm);
  transition: all var(--transition-base);
}

.menu-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(7px, 7px);
}

.menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -7px);
}

/* ========== 页面内容区域 ========== */
.main-content {
  margin-top: var(--header-height);
  min-height: calc(100vh - var(--header-height));
  background: radial-gradient(circle at 50% 0%, rgba(21, 101, 192, 0.08), transparent 45%), var(--color-background);
}

.page-section {
  padding: var(--space-3xl) 0;
  position: relative;
}

.page-section::before {
  content: '';
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: none;
  opacity: 0.18;
}

.page-section.dark {
  background: linear-gradient(140deg, #0d47a1, #0a2a56);
  color: var(--color-text-white);
  overflow: hidden;
}

.page-section.dark::before {
  background: var(--texture-tire);
  opacity: 0.22;
}

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

.page-section-title {
  text-align: center;
  margin-bottom: var(--space-2xl);
  position: relative;
  padding-bottom: var(--space-lg);
}

.page-section-title h2 {
  margin-bottom: var(--space-sm);
  color: var(--color-primary-dark);
}

.page-section-title p {
  color: var(--color-text-medium);
  max-width: 640px;
  margin: 0 auto;
}

.page-section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 72px;
  height: 4px;
  background: linear-gradient(90deg, var(--color-secondary), var(--color-primary-light));
  border-radius: var(--border-radius-full);
}

/* ========== 页脚 ========== */
.footer {
  background: linear-gradient(180deg, #0d47a1 0%, #081f3d 100%);
  color: var(--color-text-white);
  padding: var(--space-3xl) 0 var(--space-xl);
  margin-top: var(--space-3xl);
  position: relative;
  overflow: hidden;
}

.footer::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 15% 20%, rgba(255, 255, 255, 0.08), transparent 55%),
              radial-gradient(circle at 85% 30%, rgba(255, 255, 255, 0.05), transparent 60%);
  opacity: 0.6;
  pointer-events: none;
}

.footer-content {
  position: relative;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-xl);
  margin-bottom: var(--space-2xl);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

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

.footer-logo-icon {
  width: 52px;
  height: 52px;
  border-radius: 16px;
  background: linear-gradient(135deg, var(--color-secondary), rgba(21, 101, 192, 0.65));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-white);
  box-shadow: inset 0 0 0 2px rgba(255, 255, 255, 0.18);
}

.footer-logo-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  margin-bottom: 4px;
}

.footer-logo-tagline {
  font-size: var(--font-size-sm);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.64);
}

.footer-description {
  color: rgba(255, 255, 255, 0.72);
  line-height: var(--line-height-relaxed);
  font-size: var(--font-size-sm);
}

.footer-badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.footer-badge {
  padding: 6px 12px;
  border-radius: var(--border-radius-full);
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.18);
  font-size: 12px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.78);
}

.footer-section h4 {
  color: var(--color-text-white);
  margin-bottom: var(--space-md);
  font-size: var(--font-size-lg);
  letter-spacing: 0.03em;
}

.footer-section ul {
  list-style: none;
  margin-left: 0;
}

.footer-section li {
  margin-bottom: var(--space-sm);
}

.footer-section a {
  color: rgba(255, 255, 255, 0.78);
  text-decoration: none;
  transition: color var(--transition-fast), transform var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
}

.footer-section a::before {
  content: '›';
  font-size: 14px;
  opacity: 0;
  transform: translateX(-6px);
  transition: all var(--transition-fast);
}

.footer-section a:hover {
  color: var(--color-secondary);
  transform: translateX(4px);
}

.footer-section a:hover::before {
  opacity: 1;
  transform: translateX(0);
}

.footer-contact li {
  color: rgba(255, 255, 255, 0.78);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-relaxed);
}

.footer-contact strong {
  color: var(--color-text-white);
  font-weight: var(--font-weight-semibold);
}

.footer-bottom {
  position: relative;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  padding-top: var(--space-lg);
  text-align: center;
  color: rgba(255, 255, 255, 0.6);
  font-size: var(--font-size-sm);
}

.footer-bottom p {
  margin-bottom: var(--space-sm);
}

/* ========== 面包屑导航 ========== */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) 0;
  font-size: var(--font-size-sm);
  color: rgba(255, 255, 255, 0.72);
}

.breadcrumb a {
  color: var(--color-secondary);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
}

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

.breadcrumb-separator {
  color: rgba(255, 255, 255, 0.42);
}

/* ========== 卡片组件 ========== */
.card {
  background-color: var(--color-background-light);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--box-shadow-md);
  overflow: hidden;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  position: relative;
}

.card::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  border: 1px solid transparent;
  background: linear-gradient(135deg, rgba(21, 101, 192, 0.12), rgba(21, 101, 192, 0)) border-box;
  mask: linear-gradient(#fff 0 0) padding-box, linear-gradient(#fff 0 0);
  mask-composite: exclude;
  pointer-events: none;
}

.card:hover {
  box-shadow: var(--box-shadow-lg);
  transform: translateY(-6px);
}

.card-image {
  width: 100%;
  height: 260px;
  object-fit: cover;
  display: block;
}

.card-body {
  padding: var(--space-lg);
}

.card-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--space-md);
  color: var(--color-primary-dark);
}

.card-text {
  color: var(--color-text-medium);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--space-md);
}

.card-footer {
  padding: var(--space-md) var(--space-lg);
  border-top: 1px solid rgba(21, 101, 192, 0.1);
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--color-text-medium);
  font-size: var(--font-size-sm);
}

/* ========== 响应式布局 ========== */
@media (max-width: 1200px) {
  .header-inner {
    padding: 0 var(--space-lg);
  }
}

@media (max-width: 992px) {
  .nav-menu {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    flex-direction: column;
    background: linear-gradient(160deg, rgba(21, 101, 192, 0.98), rgba(38, 50, 56, 0.98));
    box-shadow: var(--box-shadow-lg);
    gap: 0;
    padding: var(--space-md) 0;
  }

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

  .nav-item {
    width: 100%;
  }

  .nav-link {
    padding: var(--space-md) var(--space-xl);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  }

  .nav-link::after {
    display: none;
  }

  .nav-submenu {
    position: static;
    opacity: 0;
    visibility: hidden;
    max-height: 0;
    overflow: hidden;
    transition: all var(--transition-base);
    box-shadow: none;
    background: rgba(255, 255, 255, 0.08);
    border: none;
  }

  .nav-item.active .nav-submenu {
    opacity: 1;
    visibility: visible;
    max-height: 520px;
  }

  .nav-submenu a {
    color: var(--color-text-white);
    border-left: 3px solid transparent;
  }

  .nav-submenu a:hover,
  .nav-submenu a:focus {
    background: rgba(255, 255, 255, 0.08);
    color: var(--color-secondary);
    border-left-color: var(--color-secondary);
  }

  .menu-toggle {
    display: flex;
  }

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

@media (max-width: 768px) {
  .header-inner {
    padding: 0 var(--space-md);
  }

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

@media (max-width: 576px) {
  .logo {
    font-size: var(--font-size-lg);
  }

  .logo-icon {
    width: 34px;
    height: 34px;
    font-size: var(--font-size-base);
  }

  .logo-tagline {
    display: none;
  }

  .nav-link {
    padding: var(--space-md) var(--space-lg);
  }

  .header-inner {
    padding: 0 var(--space-sm);
  }

  .page-section {
    padding: var(--space-2xl) 0;
  }

  .page-section-title h2 {
    font-size: var(--font-size-2xl);
  }
}