/* ==========================================================================
   responsive.css —— 响应式适配
   目标设备：Windows / Mac 桌面、平板（横竖屏）、手机

   断点策略（以内容为准，而非死记设备宽度）：
     1400px  大屏收窄三栏侧边
     1180px  实验台由"三栏"退为"两栏 + 数据横条"
      900px  平板：单栏为主，英雄区与页脚重排
      768px  手机/竖屏平板：导航折叠为汉堡菜单，画布降高
      560px  小屏手机：进一步压缩间距与字号
   ========================================================================== */

/* ------------------------- 大屏：收窄侧栏 ------------------------- */
@media (max-width: 1400px) {
  .lab-grid {
    grid-template-columns: 270px minmax(0, 1fr) 280px;
    gap: 16px;
  }
  .lab-root { max-width: 100%; }
}

/* ------------------------- 1180px：三栏 → 两栏 ------------------------- */
@media (max-width: 1180px) {
  .lab-grid {
    grid-template-columns: 272px minmax(0, 1fr);
  }
  /* 实时数据横跨整行，放在装置下方 */
  .lab-right {
    grid-column: 1 / -1;
  }
  .lab-left {
    position: static;              /* 取消吸顶，避免遮挡 */
  }
  /* 横放后指标卡改为四列，避免过高 */
  .metric-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .hero-inner {
    grid-template-columns: 1.05fr .95fr;
    gap: 30px;
  }
  .hero h1 { font-size: 38px; }
}

/* ------------------------- 900px：平板竖屏 ------------------------- */
@media (max-width: 900px) {
  .lab-grid {
    grid-template-columns: minmax(0, 1fr);
  }
  .lab-left,
  .lab-center,
  .lab-right {
    grid-column: auto;
  }
  .lab-left { position: static; }

  /* 参数面板改为两列平铺，减少纵向滚动 */
  .param-body {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 22px;
  }
  .param-item {
    padding: 12px 0;
  }
  .param-item:first-child { padding-top: 12px; }

  .metric-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }

  /* 首页 */
  .hero { padding: 52px 0 46px; }
  .hero-inner { grid-template-columns: 1fr; gap: 26px; }
  .hero h1 { font-size: 34px; }
  .hero-sub { font-size: 16px; max-width: none; }
  .hero-art { min-height: 220px; }
  .hero-art svg { height: 220px; }

  .cat-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .steps-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }

  .footer-inner { grid-template-columns: 1fr 1fr; gap: 26px; }

  .section { padding: 44px 0; }
}

/* ------------------------- 768px：手机 / 小平板 ------------------------- */
@media (max-width: 768px) {
  :root { --header-h: 58px; }

  /* 导航折叠 */
  .nav-toggle { display: flex; }
  .nav {
    display: none;
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    margin: 0;
    padding: 10px 16px 16px;
    background: #fff;
    border-bottom: 1px solid var(--line);
    box-shadow: 0 12px 24px rgba(15, 23, 42, .1);
  }
  .nav.open { display: flex; }
  .nav-link {
    padding: 12px 14px;
    font-size: 15px;
    border-radius: var(--r-s);
  }

  /* 容器与区块间距 */
  .container { padding: 0 16px; }
  .section { padding: 34px 0; }
  .section-head h2 { font-size: 21px; }

  /* 首页 */
  .hero { padding: 38px 0 34px; }
  .hero h1 { font-size: 28px; letter-spacing: -.3px; }
  .hero-sub { font-size: 15px; }
  .hero-actions { gap: 10px; }
  .hero-actions .btn { flex: 1 1 auto; }
  .hero-stats { gap: 22px; }
  .hero-stats div b { font-size: 19px; }

  .cat-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
  .cat-card { padding: 16px 14px; }
  .cat-desc { min-height: 0; }

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

  /* 实验台 */
  .lab-root { padding: 14px 16px 32px; }
  .lab-topbar { padding: 12px 14px; gap: 12px; }
  .lab-title h1 { font-size: 18px; }
  .lab-topbar-actions { margin-left: 0; width: 100%; }
  .lab-topbar-actions .btn { flex: 1; }

  #stageCanvas { height: 330px; }

  .metric-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }

  /* 参数面板恢复单列 */
  .param-body { grid-template-columns: 1fr; gap: 0; }

  /* 触摸友好：滑杆滑块加大 */
  .param-range { height: 8px; }
  .param-range::-webkit-slider-thumb { width: 24px; height: 24px; border-width: 4px; }
  .param-range::-moz-range-thumb { width: 20px; height: 20px; border-width: 4px; }

  .stage-controls { gap: 8px; padding: 12px 14px; }
  .stage-controls .btn { flex: 1 1 auto; min-width: 84px; }
  .speed-ctl { flex: 1 1 auto; }
  .progress { flex: 1 1 100%; order: 9; }
  .clock { order: 10; }

  .table-scroll { max-height: 300px; }
  .data-table { font-size: 12.5px; }
  .data-table thead th,
  .data-table tbody td { padding: 7px 9px; }

  .formula-list { grid-template-columns: 1fr; }

  /* 页脚 */
  .footer-inner { grid-template-columns: 1fr; gap: 20px; padding-bottom: 24px; }

  /* 页面头部 */
  .page-head { padding: 30px 0 20px; }
  .page-head h1 { font-size: 24px; }

  .lab-flash { left: 16px; right: 16px; transform: translate(0, 16px); text-align: center; }
  .lab-flash.show { transform: translate(0, 0); }
}

/* ------------------------- 560px：小屏手机 ------------------------- */
@media (max-width: 560px) {
  body { font-size: 14.5px; }

  .hero h1 { font-size: 24px; }
  .hero-sub { font-size: 14.5px; }
  .hero-stats { gap: 16px; margin-top: 24px; }

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

  .exp-card { padding: 18px; }
  .exp-card-foot { flex-direction: column; align-items: stretch; gap: 10px; }
  .exp-card-foot .btn { width: 100%; }

  .lab-topbar { flex-direction: column; align-items: flex-start; }
  .btn-back { width: 100%; justify-content: center; }

  #stageCanvas { height: 260px; }

  .metric-grid { grid-template-columns: 1fr 1fr; gap: 8px; }
  .metric-value b { font-size: 16px; }

  .tab { height: 32px; padding: 0 11px; font-size: 12.5px; }
  .series-ops .btn { flex: 1 1 auto; }

  .formula-expr { font-size: 14px; }

  .result-grid { grid-template-columns: 1fr 1fr; }
  .prose { padding: 16px; font-size: 14px; }

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

/* ------------------------- 触摸设备：去掉悬浮位移 ------------------------- */
@media (hover: none) {
  .exp-card:hover,
  .cat-card:hover,
  .k-card:hover { transform: none; }
}

/* ------------------------- 横屏矮屏（如平板横放） ------------------------- */
@media (max-height: 560px) and (min-width: 769px) {
  #stageCanvas { height: 300px; }
  .hero { padding: 34px 0 30px; }
}

/* ------------------------- 打印：便于学生交实验报告 ------------------------- */
@media print {
  .site-header, .site-footer, .nav-toggle,
  .stage-controls, .lab-flash, .series-ops, .tabs { display: none !important; }
  body { background: #fff; }
  .panel { box-shadow: none; break-inside: avoid; }
  .lab-grid { display: block; }
  .lab-left, .lab-center, .lab-right { margin-bottom: 12px; }
}