/* ---------- 980px：平板 / 小笔记本 ---------- */
@media (max-width: 980px) {
  .hero-grid,
  .dl-grid {
    grid-template-columns: 1fr;
    gap: 30px;
  }

  .hero-qr {
    width: 100%;
    max-width: 640px;
  }

  .stage {
    height: auto;
    min-height: 430px;
  }

  h1 {
    font-size: 38px;
  }

  .grid3,
  .rules,
  .grid4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid2 {
    grid-template-columns: repeat(2, 1fr);
  }

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

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

  .dl {
    padding: 30px;
  }

  .qrbox {
    max-width: 360px;
    width: 100%;
    margin: 0 auto;
  }

  .page-hero h1 {
    font-size: 38px;
  }

  .guide-layout,
  .legal-layout {
    grid-template-columns: 1fr;
  }

  .toc-card,
  .legal-aside {
    position: static;
  }

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

  .admin-card-flush {
    overflow-x: auto;
  }

  .error-code {
    font-size: 96px;
  }
}

/* ---------- 900px：切换为移动端导航 ---------- */
@media (max-width: 900px) {
  .nav {
    gap: 16px;
  }

  .nav-links,
  .nav-cta {
    display: none;
  }

  .nav-toggle {
    display: inline-flex;
  }
}

/* ---------- 640px：手机 ---------- */
@media (max-width: 640px) {
  h1 {
    font-size: 31px;
  }

  h2 {
    font-size: 25px;
  }

  section {
    padding: 44px 0;
  }

  .grid3,
  .grid2,
  .rules,
  .grid4,
  .cert-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding: 38px 0 18px;
  }

  .hero-grid {
    gap: 22px;
  }

  .hero-qr {
    width: 100%;
    gap: 16px;
    padding: 14px;
  }

  .hero-qr-code {
    width: 168px;
    height: 168px;
    padding: 7px;
    border-radius: 12px;
  }

  .lede {
    font-size: 15px;
  }

  /* 小屏改为竖向堆叠，避免打印机卡片覆盖聊天界面 */
  .stage {
    height: auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 14px;
    padding: 6px 0 4px;
    min-height: 0;
  }

  .phone {
    position: relative;
    right: auto;
    top: auto;
    transform: rotate(-1deg);
    width: 230px;
    height: 404px;
  }

  .printer {
    position: relative;
    left: auto;
    bottom: auto;
    transform: none;
    width: 230px;
  }

  .f1,
  .f2 {
    display: none;
  }

  .ticker {
    padding: 12px 14px;
    gap: 12px;
  }

  .ticker .tt {
    font-size: 11.5px;
  }

  .track {
    gap: 0;
  }

  .item {
    padding: 0 12px;
  }

  .dl {
    padding: 24px 20px;
    border-radius: 20px;
  }

  .dl h2 {
    font-size: 25px;
  }

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

  .site-footer {
    padding-bottom: 96px;
  }

  .foot-nav {
    gap: 28px;
  }

  .mobile-bar {
    display: flex;
  }

  .page-hero {
    padding: 38px 0 30px;
  }

  .page-hero h1 {
    font-size: 31px;
  }

  .page-hero .lede {
    margin-bottom: 18px;
  }

  .section-page {
    padding: 36px 0 54px;
  }

  .form-card {
    padding: 20px 18px;
  }

  .contact-slim-grid.has-qr {
    grid-template-columns: 1fr;
    gap: 22px;
  }

  .contact-methods dd {
    font-size: 14px;
  }

  .contact-slim-qr img {
    width: 140px;
    height: 140px;
  }

  .guide-block,
  .compat-card,
  .toc-card {
    padding: 18px;
  }

  .guide-head {
    gap: 12px;
  }

  .guide-num {
    width: 40px;
    height: 40px;
    font-size: 16px;
  }

  .split-cards,
  .check-list {
    grid-template-columns: 1fr;
  }

  .compat-head {
    align-items: flex-start;
  }

  .search-field {
    min-width: 0;
    width: 100%;
  }

  .plans-table {
    min-width: 560px;
  }

  .compat-table {
    min-width: 720px;
  }

  th,
  td {
    padding: 12px 13px;
  }

  .legal-card {
    padding: 24px 18px;
    font-size: 13.5px;
  }

  .legal-card h2 {
    font-size: 17.5px;
  }

  .cta-band {
    flex-direction: column;
    align-items: flex-start;
    padding: 24px 20px;
  }

  .cta-band h2 {
    font-size: 21px;
  }

  .error-code {
    font-size: 76px;
  }

  .error-page h1 {
    font-size: 28px;
  }

  .modal {
    width: calc(100% - 24px);
  }

  .modal-inner {
    padding: 22px 18px;
  }

  .modal-meta {
    grid-template-columns: 1fr;
  }

  .modal-actions .btn {
    min-width: 120px;
  }

  /* 运营后台 */
  .admin-top {
    padding: 0 16px;
  }

  .admin-top .logo {
    height: 58px;
    font-size: 16px;
  }

  .admin-top-badge {
    display: none;
  }

  .admin-main {
    padding: 22px 16px 64px;
  }

  .admin-heading h1 {
    font-size: 26px;
  }

  .admin-tabs {
    display: flex;
    width: 100%;
    overflow-x: auto;
  }

  .admin-tab {
    flex: none;
  }

  .stat-grid {
    gap: 10px;
  }

  .stat-card {
    padding: 16px;
  }

  .stat-card b {
    font-size: 25px;
  }

  .stat-card b.stat-top {
    font-size: 18px;
  }

  .admin-card {
    padding: 18px 16px;
  }

  .admin-card-head {
    flex-direction: column;
    gap: 6px;
  }

  .admin-list-item {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .admin-list-item time {
    justify-self: start;
  }

  .settings-grid,
  .platform-fields {
    grid-template-columns: 1fr;
  }

  .settings-actions {
    bottom: 8px;
  }
}

/* ---------- 430px：超小屏 ---------- */
@media (max-width: 430px) {
  .stat-grid {
    grid-template-columns: 1fr;
  }

  .wrap {
    padding: 0 18px;
  }

  .hero-note {
    gap: 10px;
  }

  .qr {
    width: 150px;
    height: 150px;
  }
}

/* ---------- 480px：扫码下载卡片改为上下堆叠，避免文字与标签被挤压 ---------- */
@media (max-width: 480px) {
  .hero-qr {
    flex-direction: column;
    align-items: center;
    gap: 14px;
    padding: 16px;
    text-align: center;
  }

  .hero-qr-info {
    align-items: center;
  }

  .hero-qr-info .hero-qr-tag {
    align-self: center;
  }
}