/* ============================================
   Common - 通用布局、排版、按钮、网格
   ============================================ */

/* ===== Skip Link (无障碍) ===== */
.skip-link {
  position: absolute;
  top: -60px;
  left: 0;
  padding: var(--space-3) var(--space-5);
  background: var(--color-primary);
  color: #000;
  font-size: var(--text-sm);
  font-weight: 600;
  text-decoration: none;
  border-radius: 0 0 var(--radius-md) 0;
  z-index: 10000;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 0;
}

/* ===== 容器 ===== */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.container-fluid {
  width: 100%;
  padding: 0 var(--container-padding);
}

/* ===== 板块间距 ===== */
.section {
  padding: var(--space-20) 0;
  position: relative;
  background: var(--bg-secondary);
}

.section-sm {
  padding: var(--space-16) 0;
  background: var(--bg-secondary);
}

.section-lg {
  padding: var(--space-24) 0;
  background: var(--bg-secondary);
}

/* ===== 标题排版 ===== */
.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto var(--space-12);
}

.section-title {
  font-size: var(--text-4xl);
  font-weight: 700;
  margin-bottom: var(--space-4);
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

.section-subtitle {
  font-size: var(--text-lg);
  color: var(--text-secondary);
  line-height: var(--leading-relaxed);
}

.section-tag {
  display: inline-block;
  padding: var(--space-1) var(--space-4);
  font-size: var(--text-sm);
  color: var(--color-primary);
  background: rgba(37, 99, 235, 0.1);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-4);
  letter-spacing: 0.05em;
}

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-base);
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  cursor: pointer;
  white-space: nowrap;
  border: 1px solid transparent;
  text-decoration: none;
  min-height: 48px;
}

.btn-primary {
  background: var(--gradient-primary);
  color: var(--text-inverse);
  box-shadow: 0 4px 16px rgba(37, 99, 235, 0.22);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(37, 99, 235, 0.32);
  color: var(--text-inverse);
}

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

.btn-outline:hover {
  background: rgba(37, 99, 235, 0.1);
  border-color: var(--color-primary);
  box-shadow: var(--glow-primary);
  color: var(--color-primary);
}

.btn-ghost {
  background: rgba(15, 23, 42, 0.04);
  color: var(--text-primary);
  border-color: var(--border-secondary);
}

.btn-ghost:hover {
  background: rgba(15, 23, 42, 0.06);
  border-color: var(--border-primary);
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-lg);
  min-height: 56px;
}

.btn-sm {
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-sm);
  min-height: 36px;
}

/* ===== 网格系统 ===== */
.grid {
  display: grid;
  gap: var(--space-6);
}

.grid-2 { grid-template-columns: 1fr; }
.grid-3 { grid-template-columns: 1fr; }
.grid-4 { grid-template-columns: 1fr; }

@media (min-width: 768px) {
  .grid-2 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1024px) {
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
  .grid-4 { grid-template-columns: repeat(4, 1fr); }
}

/* ===== Flex 工具类 ===== */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.flex-wrap { flex-wrap: wrap; }
.gap-2 { gap: var(--space-2); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

/* ===== 文字工具类 ===== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--text-primary); }
.text-secondary { color: var(--text-secondary); }
.text-tertiary { color: var(--text-tertiary); }
.text-accent { color: var(--color-primary); }

.text-gradient {
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* ===== 页面 Banner ===== */
.page-banner {
  padding: calc(var(--nav-height) + var(--space-20)) 0 var(--space-16);
  background: var(--gradient-hero);
  position: relative;
  overflow: hidden;
}

.page-banner::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image:
    radial-gradient(circle at 20% 50%, rgba(37, 99, 235, 0.08) 0%, transparent 50%),
    radial-gradient(circle at 80% 50%, rgba(124, 58, 237, 0.08) 0%, transparent 50%);
}

.page-banner__content {
  position: relative;
  z-index: 1;
  text-align: center;
}

.page-banner__title {
  font-size: var(--text-5xl);
  font-weight: 700;
  margin-bottom: var(--space-4);
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.page-banner__subtitle {
  font-size: var(--text-lg);
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

.breadcrumb {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  margin-top: var(--space-6);
  font-size: var(--text-sm);
  color: var(--text-tertiary);
}

.breadcrumb a {
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

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

.breadcrumb span {
  color: var(--text-tertiary);
}

/* ===== CTA 板块 ===== */
.cta-section {
  padding: var(--space-20) 0;
  background: var(--gradient-hero);
  position: relative;
  overflow: hidden;
}

.cta-section::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.1) 0%, transparent 70%);
  pointer-events: none;
}

.cta-section__content {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 640px;
  margin: 0 auto;
}

.cta-section__title {
  font-size: var(--text-4xl);
  font-weight: 700;
  margin-bottom: var(--space-4);
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.cta-section__subtitle {
  font-size: var(--text-lg);
  color: var(--text-secondary);
  margin-bottom: var(--space-8);
}

.cta-section__buttons {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  flex-wrap: wrap;
}

/* ===== 背景装饰 ===== */
.bg-decoration {
  position: absolute;
  pointer-events: none;
  z-index: 0;
}

.bg-decoration--grid {
  background-image:
    linear-gradient(rgba(37, 99, 235, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(37, 99, 235, 0.03) 1px, transparent 1px);
  background-size: 50px 50px;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
}

/* ===== 页面入场动画 ===== */
.page-enter {
  animation: pageFadeIn 0.6s ease forwards;
}

@keyframes pageFadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ===== 滚动指示器 ===== */
.scroll-indicator {
  position: absolute;
  bottom: var(--space-8);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  color: var(--text-tertiary);
  font-size: var(--text-sm);
  animation: bounce 2s infinite;
}

.scroll-indicator__arrow {
  width: 24px;
  height: 24px;
  border-right: 2px solid var(--color-primary);
  border-bottom: 2px solid var(--color-primary);
  transform: rotate(45deg);
  opacity: 0.6;
}

@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}