/* ═══════════════════════════════════════════════════════
   开封昉玑人工智能有限公司 · 全站基础样式
   配色：暖调近黑 + 单一赤陶强调色
   ═══════════════════════════════════════════════════════ */

/* ── 自托管字体（Outfit Variable，无外部依赖） ── */
@font-face{
  font-family:'Outfit Variable';font-style:normal;font-display:swap;
  font-weight:100 900;
  src:url('../assets/fonts/outfit-latin-wght-normal.woff2') format('woff2-variations');
  unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+2074,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD;
}
@font-face{
  font-family:'Outfit Variable';font-style:normal;font-display:swap;
  font-weight:100 900;
  src:url('../assets/fonts/outfit-latin-ext-wght-normal.woff2') format('woff2-variations');
  unicode-range:U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF;
}

:root{
  --bg:#12110F;
  --bg-2:#181613;
  --surface:#1E1C18;
  --surface-2:#252220;
  --line:rgba(245,243,238,.09);
  --line-2:rgba(245,243,238,.16);
  --ink:#F5F3EE;
  --ink-2:#A8A49C;
  --ink-3:#6E6A62;
  --accent:#D97757;
  --accent-soft:rgba(217,119,87,.14);
  --accent-line:rgba(217,119,87,.34);

  --font:'Outfit Variable','Outfit','Noto Sans SC','PingFang SC','Hiragino Sans GB','Microsoft YaHei',sans-serif;

  --ease:cubic-bezier(.16,1,.3,1);
  --r-sm:10px; --r-md:16px; --r-lg:22px;
  --pad:clamp(72px,10vw,132px);
}

*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;background:var(--bg);color:var(--ink);
  font-family:var(--font);font-size:16px;line-height:1.7;
  -webkit-font-smoothing:antialiased;overflow-x:hidden;
}
img,svg{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
h1,h2,h3{margin:0;font-weight:600;letter-spacing:-.02em;line-height:1.16}
p{margin:0}
ul,ol{margin:0;padding:0;list-style:none}
em{font-style:normal}

.wrap{max-width:1240px;margin:0 auto;padding:0 clamp(20px,4vw,40px)}

/* 细微颗粒质感（内联 SVG 噪声，无外链） */
.grain{position:fixed;inset:0;pointer-events:none;z-index:9999;opacity:.05;
  background-image:url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  background-size:180px 180px}

/* ── 导航 ───────────────────────────────────────── */
.nav{position:sticky;top:0;z-index:100;backdrop-filter:blur(14px);
  background:rgba(18,17,15,.72);border-bottom:1px solid transparent;
  transition:border-color .35s var(--ease),background .35s var(--ease)}
.nav.stuck{border-bottom-color:var(--line);background:rgba(18,17,15,.9)}
.nav-in{display:flex;align-items:center;gap:28px;height:70px}
.brand{display:flex;align-items:center;gap:11px;font-weight:600;font-size:17px;
  letter-spacing:-.01em;white-space:nowrap}
.logo-img{height:36px;width:auto;flex:none;display:block}
.nav-links{display:flex;gap:30px;margin-left:auto;font-size:14.5px;color:var(--ink-2)}
.nav-links a{transition:color .25s var(--ease)}
.nav-links a:hover{color:var(--ink)}
.nav-links a[aria-current="page"]{color:var(--accent)}

/* 品牌名：桌面全称 / 窄屏简称 */
.bn-short{display:none}

/* 汉堡按钮（窄屏显示） */
.nav-toggle{display:none;flex:none;width:38px;height:38px;border-radius:10px;
  background:transparent;border:1px solid var(--line-2);cursor:pointer;padding:0;
  align-items:center;justify-content:center;flex-direction:column;gap:4px;
  transition:border-color .25s var(--ease),background .25s var(--ease)}
.nav-toggle:hover{border-color:var(--ink-3);background:rgba(245,243,238,.05)}
.nav-toggle:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.nav-toggle span{display:block;width:16px;height:1.5px;border-radius:2px;background:var(--ink-2);
  transition:transform .3s var(--ease),opacity .3s var(--ease)}
.nav-toggle[aria-expanded="true"] span:nth-child(1){transform:translateY(5.5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] span:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] span:nth-child(3){transform:translateY(-5.5px) rotate(-45deg)}

/* 移动端展开菜单 */
.mnav{display:none;flex-direction:column;
  border-top:1px solid var(--line);background:rgba(18,17,15,.97);backdrop-filter:blur(14px);
  padding:6px clamp(20px,4vw,40px) 22px}
.mnav.open{display:flex}
.mnav a{padding:14px 0;font-size:16px;color:var(--ink-2);
  border-bottom:1px solid var(--line);transition:color .25s var(--ease)}
.mnav a:hover{color:var(--ink)}
.mnav a[aria-current="page"]{color:var(--accent)}
.mnav a.btn{margin-top:18px;border-bottom:0;color:#1A0F09;justify-content:center}
.mnav a.btn:hover{color:#1A0F09}

/* ── 按钮 ───────────────────────────────────────── */
.btn{display:inline-flex;align-items:center;justify-content:center;
  padding:14px 26px;border-radius:999px;font-size:15px;font-weight:500;
  background:var(--accent);color:#1A0F09;border:1px solid var(--accent);
  transition:transform .22s var(--ease),background .22s var(--ease),box-shadow .22s var(--ease);
  box-shadow:0 6px 26px -10px rgba(217,119,87,.6)}
.btn:hover{background:#E2835F;transform:translateY(-1px);box-shadow:0 12px 34px -12px rgba(217,119,87,.75)}
.btn:active{transform:scale(.98)}
.btn:focus-visible{outline:2px solid var(--accent);outline-offset:3px}
.btn-ghost{background:transparent;color:var(--ink);border-color:var(--line-2);box-shadow:none}
.btn-ghost:hover{background:rgba(245,243,238,.05);border-color:var(--ink-3);box-shadow:none}
.btn-sm{padding:10px 20px;font-size:14px}

/* ── 通用区块 ───────────────────────────────────── */
.sec{padding:var(--pad) 0}
.sec-alt{background:var(--bg-2);border-block:1px solid var(--line)}
.sec-head{display:flex;align-items:baseline;gap:16px;margin-bottom:14px}
.sec-no{font-size:12.5px;color:var(--accent);letter-spacing:.16em;font-weight:600;flex:none;padding-top:6px}
.sec-head h2{font-size:clamp(26px,3.4vw,40px);letter-spacing:-.03em}
.sec-lede{font-size:16px;color:var(--ink-2);max-width:56ch;
  margin-bottom:clamp(36px,5vw,56px);line-height:1.75}

/* 栅格 */
.grid-2,.grid-3,.grid-4{display:grid;gap:1px;background:var(--line);
  border:1px solid var(--line);border-radius:var(--r-md);overflow:hidden}
.grid-2{grid-template-columns:repeat(2,1fr)}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-4{grid-template-columns:repeat(4,1fr)}
.cell{background:var(--bg);padding:clamp(24px,3vw,34px)}
.sec-alt .cell{background:var(--bg-2)}
.cell h3{font-size:17.5px;margin-bottom:10px;letter-spacing:-.015em}
.cell p{font-size:14.5px;color:var(--ink-2);line-height:1.72}

/* 引言 */
.quote{margin-top:clamp(36px,5vw,52px);padding-left:22px;border-left:2px solid var(--accent)}
.quote p{font-size:clamp(20px,2.6vw,28px);font-weight:600;letter-spacing:-.025em;line-height:1.4}
.quote span{display:block;margin-top:8px;font-size:14.5px;color:var(--ink-3)}

/* ── 页脚 ───────────────────────────────────────── */
.foot{border-top:1px solid var(--line);padding:56px 0 44px;background:var(--bg)}
.foot-in{display:grid;grid-template-columns:1fr auto;gap:22px 40px;align-items:start}
.foot-brand{display:flex;align-items:center;gap:11px;font-weight:600;font-size:16px}
.foot-logo{height:56px;width:auto;display:block;margin-bottom:2px}
.foot-desc{font-size:13.5px;color:var(--ink-3);grid-column:1;margin-top:-8px}
.foot-links{display:flex;gap:26px;font-size:13.5px;color:var(--ink-2);
  grid-row:1/3;grid-column:2;align-items:center}
.foot-links a:hover{color:var(--accent)}
.foot-copy{grid-column:1/-1;margin-top:24px;padding-top:22px;border-top:1px solid var(--line);
  font-size:12.5px;color:var(--ink-3)}

/* ── 入场动效 ───────────────────────────────────── */
.reveal{opacity:0;transform:translateY(20px);
  transition:opacity .8s var(--ease),transform .8s var(--ease)}
.reveal[data-delay="1"]{transition-delay:.07s}
.reveal[data-delay="2"]{transition-delay:.14s}
.reveal[data-delay="3"]{transition-delay:.21s}
.reveal[data-delay="4"]{transition-delay:.28s}
.reveal[data-delay="5"]{transition-delay:.35s}
.reveal[data-delay="6"]{transition-delay:.42s}
.reveal[data-delay="7"]{transition-delay:.49s}
.reveal.in{opacity:1;transform:none}

/* ── 响应式（全站共用部分） ─────────────────────── */
@media (max-width:1040px){
  .grid-4{grid-template-columns:repeat(2,1fr)}
  .nav-links{display:none}
  .nav-cta{margin-left:auto}
  .nav-toggle{display:flex}
  .nav-in{gap:12px}
  .foot-in{grid-template-columns:1fr}
  .foot-links{grid-row:auto;grid-column:1;flex-wrap:wrap;gap:18px}
}
@media (max-width:680px){
  :root{--pad:clamp(56px,12vw,80px)}
  .grid-2,.grid-3,.grid-4{grid-template-columns:1fr}
  .brand{font-size:15px}
  .logo-img{height:29px}
  .bn-full{display:none}
  .bn-short{display:inline}
  .btn-sm{padding:9px 16px;font-size:13.5px}
}

/* ── 无障碍 ─────────────────────────────────────── */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;
    transition-duration:.01ms!important}
  .reveal{opacity:1;transform:none}
}