/* =============================================================
 * layout.css
 * 布局样式: 容器、栅格、各 Section 的整体框架
 * ============================================================= */

main {
  display: block;
  min-height: 60vh;
}

/* ---- 通用 section 间距 ---- */
section {
  padding: var(--space-2xl) 0;
}

/* ---- Section 标题区 ---- */
.section-head {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.section-title {
  font-size: var(--font-size-h2);
  font-weight: 600;
  color: var(--color-heading);
  margin: 0 0 var(--space-md);
  position: relative;
}

/* Hero 区独立使用更小一号标题 */
.hero .section-title,
.hero__title {
  font-size: var(--font-size-h2-hero);
}

.section-desc {
  max-width: 760px;
  margin: 0 auto;
  color: var(--color-text);
  font-size: var(--font-size-lg);
  line-height: 1.7;
}

/* ===================== 顶部导航布局 ===================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: #fff;
  border-bottom: 1px solid var(--color-border);
  transition: box-shadow var(--duration-base) var(--ease-out);
}

.site-header.is-scrolled {
  box-shadow: var(--shadow-sm);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 80px;
  gap: var(--space-lg);
}

.site-logo img {
  width: 56px;
  height: 56px;
  object-fit: contain;
  border-radius: 8px;
}

/* ===================== Hero ===================== */
.hero {
  position: relative;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  padding: 140px 0;
  color: var(--color-heading);
  overflow: hidden;
}

.hero__overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.6) 0%,
    rgba(255, 255, 255, 0.9) 100%
  );
  pointer-events: none;
}

.hero__inner {
  position: relative;
  z-index: 1;
  max-width: 820px;
  text-align: center;
}

.hero__title {
  font-size: var(--font-size-h2-hero);
  font-weight: 600;
  margin-bottom: var(--space-md);
}

.hero__desc {
  font-size: var(--font-size-lg);
  color: var(--color-text);
  margin-bottom: var(--space-lg);
}

.hero__cta {
  margin-bottom: var(--space-xl);
}

.hero__sub {
  font-size: 14px;
  color: #888;
  line-height: 1.7;
  max-width: 760px;
  margin: 0 auto;
}

/* ===================== 下载区 ===================== */
.download {
  background: var(--color-bg);
}

.download__intro {
  max-width: 880px;
  margin: 0 auto var(--space-xl);
  text-align: center;
  font-size: 15px;
  line-height: 1.9;
  color: #777;
}

.download__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
  margin-top: var(--space-xl);
}

/* ===================== Feature 区通用 ===================== */
.feature {
  background: var(--color-bg-alt);
}

.feature--call,
.feature--message {
  background: #fff;
}

.feature__head {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.feature__split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: var(--space-xl);
}

.feature__text .section-title {
  text-align: left;
}

.feature__text .section-desc {
  text-align: left;
  margin: 0;
  max-width: none;
}

.feature__media {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--space-md);
}

.feature__media--double {
  flex-wrap: wrap;
}

.feature__media--double .feature__img {
  flex: 1 1 360px;
  max-width: 480px;
  border-radius: var(--radius-md);
}

.feature__media--single .feature__img {
  width: 100%;
  max-width: 560px;
  border-radius: var(--radius-md);
}

/* ===================== 蓝色 CTA ===================== */
.cta-blue {
  background: var(--color-blue-overlay);
  color: #fff;
  text-align: center;
  padding: 90px 0;
}

.cta-blue__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-lg);
}

.cta-blue__title {
  color: #fff;
  font-size: 24px;
  font-weight: 400;
  margin: 0;
  max-width: 720px;
}

/* ===================== 统计区 (深蓝) ===================== */
.stats {
  background: var(--color-navy);
  color: #fff;
  padding: 80px 0;
}

.stats__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-md);
  text-align: center;
}

.stat {
  padding: var(--space-md);
}

.stat__num {
  font-size: 48px;
  font-weight: 700;
  color: #fff;
  margin-bottom: var(--space-xs);
  line-height: 1;
}

.stat__label {
  font-size: 15px;
  color: rgba(255, 255, 255, 0.85);
}

/* ===================== Footer ===================== */
.site-footer {
  background: var(--color-footer);
  color: #cfd2d4;
  padding-top: var(--space-xl);
}

.site-footer__inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: var(--space-lg);
  padding-bottom: var(--space-xl);
}

.site-footer__title {
  color: #fff;
  font-size: 18px;
  margin-bottom: var(--space-md);
}

.site-footer__desc {
  font-size: 14px;
  color: #9aa1a3;
  line-height: 1.8;
}

.site-footer__list li {
  margin-bottom: var(--space-xs);
}

.site-footer__list a {
  color: #cfd2d4;
  font-size: 14px;
  transition: color var(--duration-fast) var(--ease-out);
}

.site-footer__list a:hover {
  color: #fff;
}

.site-footer__bar {
  background: #15202a;
  padding: var(--space-md) 0;
  font-size: 13px;
  color: #7c8284;
}

.site-footer__bar-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-md);
  flex-wrap: wrap;
}

/* ===================== 响应式 ===================== */
@media (max-width: 980px) {
  .download__grid {
    grid-template-columns: 1fr;
  }

  .feature__split {
    grid-template-columns: 1fr;
  }

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

  .site-footer__inner {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 600px) {
  .hero {
    padding: 80px 0;
  }

  .stats__grid {
    grid-template-columns: 1fr;
  }

  .site-footer__inner {
    grid-template-columns: 1fr;
  }
}