/* ======================================================
   common.css  两页共用:基础变量/页眉(横幅+导航+抽屉)/页脚
   首页.html 与 list.html 都引用本文件,改动会影响两页
   ====================================================== */

/* ========== 基础 ========== */
  :root{
    --orange:#ff6a00;
    --orange-deep:#ef6c00;
    --blue:#2468f2;
    --blue-deep:#1d59d8;
    --ink:#171a1f;
    --text:#333a45;
    --muted:#6b7480;
    --line:#eef0f3;
    --bg-soft:#f5f6f7;
    --nav-h:64px;
  }
  *{margin:0;padding:0;box-sizing:border-box}
  html{scroll-padding-top:calc(var(--nav-h) + 40px)}
  body{font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;color:var(--text);background:#fff;-webkit-font-smoothing:antialiased}
  .container{max-width:var(--container);margin:0 auto;padding:0 40px}
  a{text-decoration:none;color:inherit;cursor:pointer}
  ul,ol{list-style:none}
  button{font-family:inherit}

/* ========== 顶部推广横幅(与 list.html 完全一致) ========== */
  .promo{position:relative;height:60px;display:flex;align-items:center;justify-content:center;
    background:#e60012;overflow:hidden}
  .promo-brand{font-size:19px;font-weight:800;color:#fff;margin-right:8px;letter-spacing:1px}
  .promo-text{font-size:16.5px;color:#fff;font-weight:500}
  .promo-btn{margin-left:24px;display:inline-flex;align-items:center;gap:4px;background:#fff;color:#e60012;
    font-size:13.5px;font-weight:600;padding:7px 16px;border-radius:4px;box-shadow:0 2px 10px rgba(230,0,18,.25);transition:.2s}
  .promo-btn:hover{transform:translateY(-1px);box-shadow:0 4px 14px rgba(230,0,18,.35)}
  .promo-arrow{position:absolute;top:50%;transform:translateY(-50%);border:0;background:none;font-size:28px;line-height:1;
    color:rgba(255,255,255,.7);cursor:pointer;padding:4px 10px;transition:color .2s}
  .promo-arrow:hover{color:#fff}
  .promo-arrow.prev{left:10px}.promo-arrow.next{right:52px}
  .promo-close{position:absolute;right:12px;top:50%;transform:translateY(-50%);border:0;background:none;
    font-size:24px;color:rgba(255,255,255,.85);cursor:pointer;line-height:1;padding:4px 8px;transition:color .2s}
  .promo-close:hover{color:#fff}

/* ========== 主导航(与 list.html 完全一致) ========== */
  .navbar{position:sticky;top:0;z-index:100;height:var(--nav-h);background:#fff;display:flex;transition:box-shadow .25s}
  .navbar.scrolled{box-shadow:0 6px 20px rgba(31,35,41,.09)}
  .nav-left{display:flex;align-items:center;flex:1;min-width:0;padding-left:18px}
  .hamburger{width:40px;height:40px;border:0;background:none;border-radius:8px;cursor:pointer;
    display:flex;flex-direction:column;justify-content:center;align-items:center;gap:4px;transition:background .2s}
  .hamburger:hover{background:#f2f3f5}
  .hamburger span{display:block;width:17px;height:1.8px;background:#33383f;border-radius:2px;transition:.25s}
  .hamburger:hover span:nth-child(1){transform:translateY(-1px)}
  .hamburger:hover span:nth-child(3){transform:translateY(1px)}
  .nav-divider{width:1px;height:22px;background:#e5e8ec;margin:0 14px 0 12px}
  .logo{display:flex;align-items:center;margin-right:18px;flex:none}
  .logo img{height:23px;display:block}
  .nav-menu{display:flex;height:100%;flex:none}
  .nav-item{position:relative;height:100%}
  .nav-item.has-mega{position:static}
  .nav-link{display:flex;align-items:center;height:100%;padding:0 14px;font-size:14.5px;color:#25282e;transition:color .2s;white-space:nowrap}
  .nav-link:hover{color:var(--blue)}
  .nav-item.active > .nav-link{color:var(--blue);font-weight:600}
  .nav-link .dot{width:4px;height:4px;border-radius:50%;background:#ff3b30;margin-left:3px;align-self:flex-start;margin-top:22px}

  /* 简单下拉 */
  .dropdown{position:absolute;top:100%;left:6px;min-width:186px;background:#fff;border-radius:0 0 10px 10px;
    box-shadow:0 14px 30px rgba(31,35,41,.13);padding:8px 0;opacity:0;visibility:hidden;transform:translateY(12px);
    transition:opacity .22s,transform .22s,visibility .22s}
  .nav-item:hover > .dropdown{opacity:1;visibility:visible;transform:none}
  .dropdown a{display:block;padding:9px 20px;font-size:13.5px;color:#3a4149;transition:.15s}
  .dropdown a:hover{color:var(--orange);background:#fff8f3;padding-left:24px}

  /* 大面积下拉面板(mega menu) */
  .mega{position:absolute;top:100%;left:0;right:0;background:#fff;border-top:1px solid var(--line);
    box-shadow:0 22px 44px rgba(31,35,41,.12);opacity:0;visibility:hidden;transform:translateY(12px);
    transition:opacity .25s,transform .25s,visibility .25s}
  .nav-item.has-mega:hover > .mega{opacity:1;visibility:visible;transform:none}
  .mega-inner{max-width:var(--container);margin:0 auto;padding:30px 40px 34px;display:flex;gap:44px}
  .mega-col{flex:1;min-width:0}
  .mega-col h5{font-size:13px;color:#98a1ab;font-weight:600;margin-bottom:12px;padding-bottom:8px;border-bottom:1px solid #f4f5f7}
  .mega-col a{display:block;font-size:13px;color:#3a4149;line-height:2.3;transition:.15s;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
  .mega-col a:hover{color:var(--orange);transform:translateX(3px)}
  .mega-col.hot a{position:relative;padding-right:44px}
  .mega-col.hot a::after{content:'HOT';position:absolute;font-size:9px;color:#fff;background:linear-gradient(90deg,#ff8a2b,#ff3b30);
    border-radius:3px;padding:1px 4px;margin-left:8px;top:50%;transform:translateY(-50%);font-weight:700;letter-spacing:.5px}

  /* 大模型 mega(官方同款:左导语栏 + 横幅卡 + 栏目矩阵) */
  .mega-l{display:flex}
  .mega-rail{width:232px;flex:none;background:#fafbfc;border-right:1px solid #f0f1f3;padding:28px 24px}
  .rail-title{display:flex;align-items:center;gap:5px;font-size:16px;font-weight:700;color:var(--ink)}
  .rail-title svg{color:#98a1ab}
  .rail-desc{font-size:12px;color:#98a1ab;line-height:1.9;margin-top:12px}
  .mega-main{flex:1;min-width:0;padding:20px 36px 24px}
  .dm-cards{display:grid;grid-template-columns:1fr 1fr;gap:14px}
  .dm-card{border:1px solid #ececee;border-radius:8px;padding:13px 18px;transition:.2s}
  .dm-card:hover{border-color:#ffd9b8;background:#fffaf5}
  .dm-card-t{display:flex;align-items:center;gap:6px;font-size:14.5px;font-weight:700;color:var(--ink)}
  .dm-card-t svg{color:#98a1ab;flex:none}
  .dm-card-d{font-size:12px;color:#98a1ab;line-height:1.6;margin-top:6px}
  .dm-g{font-size:14px;font-weight:700;color:var(--ink);margin:20px 0 0}
  .dm-row{display:grid;grid-template-columns:2fr 1.1fr 1.1fr;gap:0 36px;padding-top:8px}
  .dm-row.four{grid-template-columns:repeat(4,1fr);margin-top:8px;padding-top:14px;border-top:1px solid #f4f5f7}
  .dm-h{display:flex;align-items:center;gap:6px;font-size:13.5px;font-weight:700;color:var(--ink);padding:7px 0}
  .dm-h svg{color:#b9c0ca;flex:none}
  .dm-list2{display:grid;grid-template-columns:1fr 1fr;gap:0 28px}
  .dm-item{display:block;padding:7px 0}
  .dm-name{display:flex;align-items:center;gap:6px;font-size:13px;font-weight:600;color:#2b3038;transition:color .15s;white-space:nowrap;overflow:hidden}
  .dm-name svg{flex:none;color:#c3c9d2}
  .dm-item:hover .dm-name{color:var(--orange)}
  .dm-desc{display:block;font-size:11.5px;color:#98a1ab;margin-top:3px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
  .b-new,.b-hot{flex:none;font-style:normal;font-size:10px;font-weight:800;letter-spacing:.3px;line-height:1}
  .b-new{color:#2468f2}
  .b-hot{color:#ff3b30}

  .nav-right{display:flex;align-items:center;flex:none}
  .search{position:relative;width:380px;margin-right:10px}
  .search input{width:100%;height:38px;border:1px solid #e3e6ea;border-radius:6px;padding:0 40px 0 14px;
    font-size:13.5px;color:#2b3038;outline:none;background:#fff;transition:.2s}
  .search input::placeholder{color:#a4abb5}
  .search input:focus{border-color:var(--blue);box-shadow:0 0 0 3px rgba(36,104,242,.08)}
  .search svg{position:absolute;right:13px;top:50%;transform:translateY(-50%);pointer-events:none}
  .icon-btn{width:34px;height:34px;border-radius:8px;display:flex;align-items:center;justify-content:center;color:#454b53;transition:.2s}
  .icon-btn:hover{background:#f2f3f5;color:var(--blue)}
  .txt-link{padding:0 11px;font-size:14px;color:#2b3038;transition:color .2s;white-space:nowrap}
  .txt-link:hover{color:var(--blue)}
  .login-btn{margin-left:6px;width:96px;height:var(--nav-h);flex:none;display:flex;align-items:center;justify-content:center;
    background:var(--blue);color:#fff;font-size:15px;transition:background .2s}
  .login-btn:hover{background:var(--blue-deep)}

/* ========== 左侧抽屉(与 list.html 完全一致) ========== */
  .drawer-mask{position:fixed;inset:0;background:rgba(23,26,31,.4);z-index:198;opacity:0;visibility:hidden;transition:.25s}
  .drawer-mask.show{opacity:1;visibility:visible}
  .drawer{position:fixed;top:0;left:0;bottom:0;width:300px;background:#fff;z-index:199;padding:22px 0;
    transform:translateX(-102%);transition:transform .3s cubic-bezier(.22,.8,.36,1);overflow-y:auto}
  .drawer.open{transform:none}
  .drawer .d-logo{padding:0 24px 18px;border-bottom:1px solid var(--line)}
  .d-logo img{height:20px;display:block}
  .drawer a.d-link{display:block;padding:13px 24px;font-size:15px;color:#33383f;transition:.15s}
  .drawer a.d-link:hover{background:#fff8f3;color:var(--orange);padding-left:30px}
  .drawer .d-sub{border-top:1px solid var(--line);margin-top:14px;padding-top:14px}

  .reveal{opacity:0;transform:translateY(26px);transition:opacity .6s ease,transform .6s ease}
  .reveal.in{opacity:1;transform:none}

/* ========== 页脚(与 list.html 完全一致) ========== */
  .footer{border-top:1px solid var(--line);background:#fafbfc;padding:38px 0 30px;margin-top:10px}
  .footer-inner{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:18px}
  .f-logo img{height:19px;display:block}
  .f-left p{font-size:12.5px;color:#98a1ab;margin-top:6px}
  .f-links{display:flex;gap:26px;flex-wrap:wrap}
  .f-links a{font-size:13px;color:var(--muted);transition:color .2s}
  .f-links a:hover{color:var(--orange)}
  .f-copy{font-size:12px;color:#a4abb5;margin-top:20px}

  /* ========== 响应式(页眉页脚共用) ========== */
  @media (max-width:1500px){ .search{width:300px} }
  @media (max-width:1360px){
    .search{width:220px}
    .icon-btn{display:none}
    .txt-link{padding:0 8px}
  }
  @media (max-width:1180px){
    .nav-menu{display:none}
    .search{width:180px}
  }
  @media (max-width:640px){
    .container{padding:0 20px}
    .promo-text{display:none}
    .search{display:none}
    .txt-link{display:none}
  }