/* ==========================================================================
   layout.css — 顶部导航、页脚、响应式框架
   ========================================================================== */

/* -------------------------------- 顶部导航 ------------------------------- */
.nav {
  position: sticky;
  top: 0;
  z-index: var(--z-nav);
  background: #fff;
}

.nav__inner {
  display: flex;
  align-items: center;
  height: var(--nav-h);
}

/* 品牌：图标 + 中英双行字标 */
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.brand__mark { width: 36px; height: 36px; }

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand__name {
  font-size: 16px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.brand__en {
  font-family: var(--font-num);
  font-size: 10px;
  font-weight: 500;
  color: var(--muted);
  letter-spacing: 0.01em;
}

.nav__menu {
  display: flex;
  align-items: center;
  gap: 38px;
  margin-inline: auto;
}

.nav__link {
  position: relative;
  font-size: 16px;
  color: var(--text);
  transition: color .18s;
}

.nav__link:hover { color: var(--brand); }

.nav__link[aria-current="page"] {
  color: var(--brand);
  font-weight: 500;
}

/* 移动端菜单按钮 */
.nav__toggle {
  display: none;
  width: 40px;
  height: 40px;
  margin-left: auto;
  align-items: center;
  justify-content: center;
}

.nav__toggle span {
  position: relative;
  display: block;
  width: 18px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
}

.nav__toggle span::before,
.nav__toggle span::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
}

.nav__toggle span::before { top: -6px; }
.nav__toggle span::after { top: 6px; }

/* -------------------------------- 页脚 ---------------------------------- */
.footer {
  padding-top: 72px;
  padding-bottom: 32px;
}

.footer__grid {
  display: flex;
  justify-content: space-between;
  gap: 48px;
  padding-bottom: 48px;
}

.footer__brand {
  max-width: 420px;
}

.footer__desc {
  margin-top: 20px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--muted);
}

.footer__cols {
  display: flex;
  gap: 200px;
}

.footer__col-title {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 18px;
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer__links a {
  font-size: 15px;
  color: var(--muted);
  transition: color .18s;
}

.footer__links a:hover { color: var(--brand); }

.footer__bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  color: var(--muted);
}

.footer__legal {
  display: flex;
  align-items: center;
  gap: 12px;
}

.footer__legal span { color: #D9CCC6; }

/* ------------------------------- 响应式 --------------------------------- */
@media (max-width: 1080px) {
  .nav__menu { gap: 28px; }
  .footer__cols { gap: 56px; }
}

@media (max-width: 900px) {
  :root {
    --section-y: 64px;
    --nav-h: 64px;
  }

  .h1 { font-size: 40px; }
  .h2 { font-size: 28px; }
  .h3 { font-size: 21px; }

  .brand__mark { width: 30px; height: 30px; }
  .brand__name { font-size: 15px; }
  .brand__en { font-size: 9px; }

  /* 移动端导航：默认收起，点击展开 */
  .nav__toggle { display: flex; }
  .nav__cta { display: none; }

  .nav__menu {
    position: absolute;
    top: var(--nav-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    margin: 0;
    padding: 8px 24px 20px;
    background: #fff;
    border-bottom: 1px solid var(--line);
    display: none;
  }

  .nav__menu.is-open { display: flex; }

  .nav__link {
    width: 100%;
    padding: 14px 0;
    font-size: 16px;
  }

  .footer__grid { flex-direction: column; gap: 40px; }
  .footer__cols { flex-wrap: wrap; gap: 40px 56px; }
  .footer__bottom { flex-direction: column; align-items: flex-start; gap: 12px; }
}

@media (max-width: 560px) {
  .footer__cols { gap: 32px 40px; }
}