/* ============================================================
   RESPONSIVE-MOBILE — 统一移动端响应式样式
   拓跋云 V4

   覆盖范围：首页(index.html) + 全部子页面
   断点策略：
     ≤1024px — 平板/小屏笔记本
     ≤768px  — 手机横屏/大屏手机
     ≤480px  — 小屏手机

   设计原则：
   - 仅覆盖移动端，PC体验完全不变
   - 所有子页面和首页共用同一套断点
   - 按功能模块分组，便于维护
   ============================================================ */

/* ============================================================
   BREAKPOINT 1 — 平板/小屏笔记本 (≤1024px)
   ============================================================ */
@media (max-width: 1024px) {

  /* ---------- Homepage Hero ---------- */
  .hero .container {
    grid-template-columns: 1fr;
    gap: var(--space-10);
  }
  .hero-overlay {
    background: linear-gradient(180deg,
      rgba(255,255,255,0.95) 0%,
      rgba(255,255,255,0.85) 45%,
      rgba(255,255,255,0.35) 75%,
      rgba(255,255,255,0.10) 100%
    );
  }
  .hero h1 { font-size: 30px; }
  .hero-subtitle { max-width: 100%; }
  .hero-panel { padding: 24px 20px; }

  /* ---------- Homepage About ---------- */
  .about-hero-row-v2 { grid-template-columns: 1fr; }
  .about-visual { min-height: 300px; }
  .about-content { padding: 36px 28px; }
  .about-content h3 { font-size: 18px; }

  /* ---------- Homepage Process Flow ---------- */
  .pf-step[data-step="4"] { padding-bottom: 55px; }
  .pf-step[data-step="5"] { padding-bottom: 120px; }
  .pf-step[data-step="6"] { padding-bottom: 190px; }
  .pf-step[data-step="7"] { padding-bottom: 250px; }
  .pf-body h4 { font-size: 12px; }
  .pf-body p { font-size: 10.5px; }

  /* ---------- Homepage Case Studies ---------- */
  .client-case-row { grid-template-columns: repeat(2, 1fr); }

  /* ---------- Homepage Services ---------- */
  .services-new { grid-template-columns: 1fr; }
  .services-sidebar { min-height: auto; padding: 32px 20px; }
  .services-grid-new { grid-template-columns: repeat(2, 1fr); }
  .services-grid-new .service-item-new:last-child:nth-child(odd) {
    grid-column: 1 / -1;
    max-width: 50%;
    justify-self: center;
    width: 100%;
  }

  /* ---------- Homepage Training ---------- */
  .training-grid { grid-template-columns: repeat(2, 1fr); }

  /* ---------- Homepage Clients ---------- */
  .client-grid { grid-template-columns: repeat(4, 1fr); }

  /* ---------- Homepage News + FAQ ---------- */
  .news-section-wrapper { grid-template-columns: 1fr; }
  .faq-sidebar { display: block; }
  .faq-a { display: none; }
  .faq-item.open .faq-a { display: flex; }
  .faq-item { cursor: pointer; }

  /* ---------- Homepage Contact ---------- */
  .contact-wrapper { grid-template-columns: 1fr; }

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

  /* ---------- Inner Page Banners ---------- */
  .page-banner {
    padding-top: 100px;
    padding-bottom: 40px;
  }

  /* ---------- Page: Case Studies (List) ---------- */
  .case-card-featured { grid-template-columns: 1fr; }
  .ccf-image { min-height: 240px; }
  .ccf-body { padding: 28px; }
  .case-grid { grid-template-columns: repeat(2, 1fr); }
  .metrics-grid { grid-template-columns: repeat(2, 1fr); }
  .case-filter-bar { gap: 16px; padding: 16px 20px; }
  .case-hero-stats { gap: 32px; }
  .case-info-grid { grid-template-columns: repeat(2, 1fr); }
  .case-info-item:nth-child(1),
  .case-info-item:nth-child(2),
  .case-info-item:nth-child(3) {
    border-bottom: 1px solid var(--border-light);
  }
  .case-info-item:nth-child(2),
  .case-info-item:nth-child(4) {
    border-right: none;
  }

  /* ---------- Page: News List ---------- */
  .fa-card { grid-template-columns: 1fr; }
  .fa-image { min-height: 220px; }
  .fa-content { padding: 28px; }
  .layout-main-sidebar { grid-template-columns: 1fr; }
}

/* ============================================================
   BREAKPOINT 2 — 手机/移动端 (≤768px)
   ============================================================ */
@media (max-width: 768px) {

  /* ========== BASE ========== */
  body { font-size: 15px; }
  .container, .container-narrow { padding: 0 16px; }

  /* ========== TYPOGRAPHY ========== */
  .section { padding: 40px 0; }
  .section-header { max-width: 100%; margin-bottom: 28px; }
  .section-header.centered { margin: 0 auto 28px; }
  .section-title { font-size: clamp(22px, 5vw, 30px); }
  .section-desc { font-size: 14px; }
  .prose h2 { font-size: 20px; }
  .prose h3 { font-size: 17px; }

  /* ========== NAVIGATION — 全屏遮罩汉堡菜单 ========== */
  .nav-menu {
    display: none;
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: var(--bg-white);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 16px;
    z-index: 1000;
  }
  .nav-menu.open { display: flex; }
  .nav-menu a,
  .nav-menu li a { font-size: 20px; padding: 14px 40px; }
  .nav-phone { display: none; }
  .nav-toggle { display: block; }
  .navbar { padding: 12px 0; }
  .nav-brand .logo-img { height: 40px; }

  /* ========== INNER PAGE BANNERS (统一) ========== */
  .page-hero, .service-hero, .about-hero, .case-hero,
  .news-hero, .training-hero, .contact-hero {
    padding: 48px 0 48px;
    min-height: auto;
    align-items: center;
  }
  .page-hero h1, .service-hero h1, .about-hero h1,
  .case-hero h1, .news-hero h1, .training-hero h1,
  .contact-hero h1 { font-size: 24px; }
  .hero-desc, .sh-desc, .nh-desc { font-size: 14px; max-width: 100%; }
  .hero-badge, .sh-badge, .nh-badge {
    font-size: 11px; padding: 4px 14px; margin-bottom: 12px;
  }
  .page-banner h1 { font-size: 26px; }
  .page-banner p { font-size: 14px; }

  /* ========== HOMEPAGE HERO ========== */
  .hero {
    padding-top: 70px;
    min-height: 50vh;
  }
  .hero .container {
    padding-top: 30px;
    padding-bottom: 40px;
  }
  .hero h1 { font-size: 26px; line-height: 1.25; }
  .hero .hero-subtitle { font-size: 14px; }
  .hero-panel { padding: 20px 16px; }
  .hero-stats { gap: 12px; }
  .hero-actions { gap: 10px; }

  /* ========== HOMEPAGE ABOUT ========== */
  .about-founder { grid-template-columns: 1fr; gap: 32px; }
  .founder-photo-wrap { max-width: 260px; margin: 0 auto; }
  .founder-creds { grid-template-columns: repeat(2, 1fr); }
  .about-stats-bar {
    grid-template-columns: repeat(2, 1fr);
    margin-top: 40px;
    padding: 28px 16px;
  }
  .about-stats-bar .sb-item:not(:last-child)::after { display: none; }
  .about-hero-row-v2 { gap: 24px; }

  /* ========== HOMEPAGE SERVICES-NEW ========== */
  .services-new { gap: 24px; }
  .services-grid-new { grid-template-columns: 1fr; }
  .services-grid-new .service-item-new:last-child:nth-child(odd) {
    max-width: 100%;
  }
  .services-sidebar { padding: 24px 16px; }
  .services-bottom-cta {
    flex-direction: column;
    gap: 12px;
    text-align: center;
    padding: 18px;
  }

  /* ========== HOMEPAGE PROCESS FLOW ========== */
  .process-flow { padding: 0; }
  .pf-lines-svg { display: none; }
  .pf-steps-row {
    flex-direction: column;
    align-items: flex-start;
    padding: 0 0 0 22px;
    max-width: 400px;
    margin: 0 auto;
  }
  .pf-step {
    flex: none;
    flex-direction: row;
    max-width: 100%;
    width: 100%;
    align-items: flex-start;
    padding-bottom: 0 !important;
    gap: 0;
  }
  .pf-step .pf-circle { flex-shrink: 0; }
  .pf-step .pf-body {
    text-align: left;
    padding: 0 0 20px 20px;
    margin-top: 0;
    border-left: 2px solid var(--red-200);
    min-height: 50px;
  }
  .pf-step:last-child .pf-body { border-left-color: transparent; padding-bottom: 0; }

  /* ========== HOMEPAGE CASE STUDIES ========== */
  .client-case-row { grid-template-columns: 1fr; }

  /* ========== HOMEPAGE CLIENTS ========== */
  .client-grid { grid-template-columns: repeat(3, 1fr); }
  .client-item { height: 60px; font-size: 12px; }

  /* ========== HOMEPAGE TRAINING ========== */
  .training-grid { grid-template-columns: 1fr; }
  .training-header { gap: 20px; }

  /* ========== HOMEPAGE NEWS + FAQ ========== */
  .news-section-wrapper { gap: 24px; }
  .news-main { padding: 16px; }
  /* 边框覆盖移至 index.html 内联 <style>（内部样式表优先级高于外部） */
  .news-tabs-bar { flex-wrap: wrap; gap: 8px; }
  .news-tabs { gap: 18px; }
  .news-tab { font-size: 13px; }
  .news-fcard { flex-direction: column; }
  .news-fimg { width: 100%; height: 140px; }

  /* ========== HOMEPAGE CONTACT ========== */
  .contact-wrapper { gap: 32px; }
  .contact-form { padding: var(--space-6); }
  .contact-form h3 { font-size: 18px; }
  .form-row { grid-template-columns: 1fr; }

  /* ========== LAYOUT GRIDS ========== */
  .grid-2, .grid-3, .grid-4,
  .card-grid-3, .card-grid-4 { grid-template-columns: 1fr; }
  .split-layout { grid-template-columns: 1fr; gap: 32px; }
  .layout-main-sidebar { grid-template-columns: 1fr; }

  /* ========== SHARED COMPONENTS ========== */

  /* Feature cards */
  .feature-grid { grid-template-columns: 1fr; }
  .feature-card { padding: 24px 20px; }

  /* Service intro card */
  .service-intro-card {
    grid-template-columns: 1fr;
    padding: 24px;
    margin-top: -20px;
    gap: 20px;
  }
  .service-intro-card .sic-highlights { gap: 20px; }

  /* Service grid (2-col on mobile) */
  .service-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
  .service-card-main { padding: 24px 16px; }
  .service-card-main .scm-icon { width: 52px; height: 52px; font-size: 24px; }
  .service-card-main h4 { font-size: 15px; }

  /* Stats bar */
  .stats-bar { grid-template-columns: repeat(2, 1fr); }
  .stat-item { padding: 20px 12px; }
  .stat-item:nth-child(even) { border-right: none; }

  /* Process steps (shared) */
  .process-steps { grid-template-columns: 1fr; }
  .process-step {
    padding: 16px 0;
    display: flex;
    align-items: center;
    gap: 16px;
    text-align: left;
  }
  .process-step .step-num { margin: 0; flex-shrink: 0; }

  /* Tab system */
  .tab-nav { flex-direction: column; gap: 0; }
  .tab-btn {
    text-align: left;
    padding: 14px 0;
    border-bottom: 1px solid var(--border-light);
  }
  .tab-btn.active::after { display: none; }
  .tab-btn.active { border-bottom-color: var(--red-500); }

  /* Tech / MA function blocks */
  .tech-block {
    grid-template-columns: 1fr;
    padding: 24px 0;
    gap: 20px;
  }
  .ma-function-block,
  .ma-function-block.reverse {
    grid-template-columns: 1fr;
    direction: ltr;
    padding: 32px 0;
    gap: 24px;
  }
  .efficiency-compare { grid-template-columns: 1fr; }

  /* Web build features */
  .wb-feature-list li { flex-direction: column; gap: 8px; }

  /* Case highlight */
  .case-highlight { padding: 24px; }
  .case-highlight .ch-stats { flex-direction: column; gap: 16px; }

  /* News card horizontal */
  .news-card-h .nch-link { flex-direction: column; }
  .nch-thumb { width: 100%; height: 160px; }

  /* Buttons */
  .btn { padding: 12px 24px; font-size: 13px; }
  .btn-lg { padding: 14px 32px; font-size: 15px; }
  .btn-sm { padding: 8px 18px; font-size: 12px; }

  /* CTA section */
  .cta-section { padding: 40px 16px; }
  .cta-section h2 { font-size: 22px; }

  /* FAQ (shared) */
  .faq-question { font-size: 15px; padding: 16px 0; }
  .faq-list { padding: 0; }

  /* Pricing */
  .pricing-info { padding: 28px 20px; }

  /* Block gray */
  .block-gray { padding: 32px 0; margin: 24px 0; border-radius: var(--radius-md); }

  /* Breadcrumb */
  .breadcrumb { padding-top: 80px; font-size: 12px; }

  /* Filter tags */
  .service-filter { gap: 6px; }
  .service-filter .filter-tag { padding: 6px 14px; font-size: 12px; }

  /* Related services */
  .related-services { padding: 20px 0 40px; }

  /* ========== FOOTER ========== */
  .footer { padding: 32px 0 0; }
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 0;
    padding-bottom: 0;
    margin-bottom: 0;
  }
  .footer-brand { grid-column: 1; }
  /* Footer accordion: brand always visible, other columns collapsible */
  .footer-col:first-child { padding: 8px 0 16px; }
  .footer-col:first-child p { margin-bottom: 4px; }
  .footer-col:not(:first-child) {
    border-bottom: 1px solid rgba(255,255,255,0.12);
  }
  .footer-col h4 {
    padding: 14px 0;
    margin-bottom: 0;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    user-select: none;
  }
  .footer-col h4::after {
    content: '+';
    position: static;
    width: auto;
    height: auto;
    background: none;
    border-radius: 0;
    font-size: 18px;
    font-weight: 300;
    opacity: 0.6;
    transition: transform 0.3s ease;
  }
  .footer-col.open h4::after {
    content: '\2212';
  }
  /* Hide content by default */
  .footer-col:not(:first-child) a,
  .footer-col:not(:first-child) p:not(.footer-brand-desc) {
    display: none;
  }
  .footer-col.open a,
  .footer-col.open p {
    display: block;
    padding: 6px 0;
    font-size: 13px;
  }
  .footer-col.open {
    padding-bottom: 12px;
  }
  .footer-bottom {
    flex-direction: column;
    text-align: center;
    gap: 8px;
    padding: 16px 0;
  }

  /* ========== FLOATING BAR ========== */
  .floating-bar { gap: 4px; }
  .floating-bar a { width: 32px; height: 32px; }
  .floating-bar svg { width: 14px; height: 14px; }

  /* ========== PAGE: NEWS ========== */
  .nch-link { flex-direction: column; }
  .nch-thumb { width: 100%; height: 180px; }
  .news-sidebar { margin-top: 32px; }
  .related-grid { grid-template-columns: 1fr; }
  .article-cta { padding: 32px 20px; }
  .author-bio { flex-direction: column; }

  /* ========== PAGE: CASES ========== */
  .case-grid { grid-template-columns: 1fr; }
  .metrics-grid { grid-template-columns: 1fr; }
  .ccf-stats { flex-wrap: wrap; }
  .case-filter-bar { flex-direction: column; }
  .case-hero-stats { gap: 24px; }
  .case-section { padding: 40px 0; }
  .case-info-grid { grid-template-columns: 1fr; }
  .case-info-item { border-right: none !important; }
  .challenge-item, .solution-block { padding: 20px; }
  .sol-header h3 { font-size: 16px; }
  .results-table th, .results-table td { padding: 10px 12px; font-size: 12px; }
  .testimonial-quote p { font-size: 15px; }
  .testimonial-quote-mark { font-size: 56px; }

  /* ========== PAGE: TRAINING ========== */
  .course-overview, .curriculum-modules,
  .learning-outcomes, .enrollment-info { max-width: 100%; }
  .co-highlights { padding: 16px; gap: 8px; }
  .co-highlight { min-width: 80px; padding: 6px 10px; }
  .co-highlight strong { font-size: 16px; }
  .trainer-section { grid-template-columns: 1fr; padding: 24px; }
  .trainer-image { max-width: 240px; }
  .who-should { grid-template-columns: 1fr; }
  .ei-grid { grid-template-columns: 1fr; }
  .lo-item { gap: 14px; padding: 18px 0; }
  .cm-title { font-size: 14px; }
  .ei-item { padding: 18px; }
  .training-card .tc-image { height: 180px; }
  .training-card .tc-content { padding: 22px; }
  .training-card h3 { font-size: 18px; }
  .training-card p { font-size: 13px; }
  .training-card .tc-tag { font-size: 12px; }

  /* ========== PAGE: ABOUT ========== */
  .founder-section { grid-template-columns: 1fr; gap: 24px; padding: 24px; }
  .values-grid { grid-template-columns: 1fr; }

  /* ========== PAGE: CONTACT ========== */
  .contact-layout { grid-template-columns: 1fr; }
}

/* ============================================================
   BREAKPOINT 3 — 小屏手机 (≤480px)
   ============================================================ */
@media (max-width: 480px) {

  /* ---------- Homepage Hero ---------- */
  .hero { min-height: 60vh; }
  .hero h1 { font-size: 24px; }
  .hero-actions {
    flex-direction: column;
    width: 100%;
  }
  .hero-actions .btn {
    width: 100%;
    justify-content: center;
  }
  .hero-panel { padding: 16px 12px; }

  /* ---------- Homepage Clients ---------- */
  .client-grid { grid-template-columns: repeat(2, 1fr); }

  /* ---------- Homepage About ---------- */
  .founder-creds { grid-template-columns: 1fr; }
  .about-stats-bar {
    grid-template-columns: repeat(2, 1fr);
    padding: 24px 16px;
  }
  .about-stats-bar .sb-num { font-size: 28px; }

  /* ---------- Homepage Stats ---------- */
  .stat-item { padding: 14px 12px; }
  .stat-item .num { font-size: 26px; }

  /* ---------- Homepage Contact ---------- */
  .contact-form { padding: var(--space-6); }

  /* ---------- Footer ---------- */
  .footer-grid { grid-template-columns: 1fr; }
  .footer { padding-bottom: 80px; }

  /* ---------- WeChat card ---------- */
  .info-card-wechat { flex-wrap: wrap; }
  .info-card-wechat .wechat-qr { margin-left: 0; margin-top: 10px; }

  /* ---------- Page banners ---------- */
  .page-banner h1 { font-size: 22px; }

  /* ---------- Buttons ---------- */
  .btn { padding: 10px 20px; font-size: 13px; }
  .btn-lg { padding: 12px 24px; font-size: 14px; }
}

/* ============================================================
   BREAKPOINT 4 — Section spacing adjustments
   桌面端 section padding 标准化（不影响PC已有规则）
   ============================================================ */
@media (min-width: 1024px) {
  /* 统一子页面 section padding，与首页V3风格一致 */
  .section { padding: 80px 0; }
}

/* ============================================================
   BREAKPOINT 5 — 平板横屏/竖屏过渡
   确保 768px-1023px 之间的平板设备有良好体验
   ============================================================ */
@media (min-width: 769px) and (max-width: 1024px) {
  .container, .container-narrow { padding: 0 24px; }

  .service-grid { grid-template-columns: repeat(3, 1fr); }
  .service-intro-card { grid-template-columns: 1fr; }
  .feature-grid { grid-template-columns: repeat(3, 1fr); }
  .split-layout { grid-template-columns: 1fr; }
  .ma-function-block,
  .ma-function-block.reverse {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  .tech-block { grid-template-columns: 1fr; }
  .efficiency-compare { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-bar { grid-template-columns: repeat(3, 1fr); }
  .layout-main-sidebar { grid-template-columns: 1fr 240px; }

  /* ─── AI Comparison Table → Cards ────────── */
  .data-table.ai-compare { display: none; }
  .ai-compare-cards { display: flex !important; flex-direction: column; gap: 12px; }
  .ai-compare-card {
    background: var(--bg-white);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    padding: 16px;
    display: grid;
    grid-template-columns: 80px 1fr;
    gap: 12px;
    align-items: center;
  }
  .ai-compare-card .acc-label {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-primary);
    background: var(--red-50);
    padding: 4px 8px;
    border-radius: 4px;
    text-align: center;
  }
  .ai-compare-card .acc-content {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.6;
  }
  .ai-compare-card .acc-content strong { color: var(--red-500); }
}

@media (max-width: 480px) {
  .ai-process-steps { grid-template-columns: repeat(2, 1fr); }
}