/* =========================================================
   AI书画 (aishuhua.com) · 全局设计系统
   视觉语言：宣纸底 × 墨黑 × 科技青/金渐变 · 响应式全端
   ========================================================= */

:root {
  /* 色板 */
  --ink:        #14110f;
  --ink-soft:   #2b2622;
  --paper:      #f6f1e7;
  --paper-2:    #fffdf8;
  --paper-3:    #efe7d8;
  --line:       #e3d9c4;
  --tech-cyan:  #00e0cf;
  --tech-blue:  #3a86ff;
  --gold:       #c9a227;
  --gold-soft:  #e0bf5c;
  --rose:       #e2554f;
  --text:       #211c18;
  --text-2:     #5c534a;
  --text-3:     #6f6659;   /* 对比度优化：原 #8a8073 在宣纸底上仅约 3.3:1，调深至约 5:1 达 WCAG AA */

  --grad-tech:  linear-gradient(120deg, #00e0cf 0%, #3a86ff 50%, #c9a227 100%);
  --grad-ink:   linear-gradient(135deg, #1a1714 0%, #2b2622 60%, #3a322a 100%);
  --grad-paper: linear-gradient(180deg, #fffdf8 0%, #f6f1e7 100%);

  --shadow-sm:  0 2px 10px rgba(20,17,15,.06);
  --shadow-md:  0 10px 30px rgba(20,17,15,.10);
  --shadow-lg:  0 24px 60px rgba(20,17,15,.16);

  --radius:     18px;
  --radius-sm:  12px;
  --maxw:       1200px;

  --font-serif: "Noto Serif SC", "Songti SC", "STSong", "SimSun", serif;
  --font-sans:  "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
}

/* ---------- 基础 ---------- */
* { margin:0; padding:0; box-sizing:border-box; }
html { scroll-behavior:smooth; }
body {
  font-family: var(--font-sans);
  color: var(--text);
  background: var(--paper);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display:block; }
ul { list-style: none; }
h1,h2,h3,h4 { font-family: var(--font-serif); font-weight:700; line-height:1.25; color: var(--ink); }
.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }
.section { padding: 88px 0; position: relative; }
.section--tight { padding: 60px 0; }

.grad-text {
  background: var(--grad-tech);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: transparent;
}
.eyebrow {
  display:inline-flex; align-items:center; gap:8px;
  font-size: 13px; letter-spacing: .22em; text-transform: uppercase;
  color: var(--gold); font-weight: 700; margin-bottom: 14px;
}
.eyebrow::before { content:""; width:26px; height:2px; background: var(--grad-tech); border-radius:2px; }
.lead { color: var(--text-2); font-size: 17px; max-width: 720px; }

/* ---------- 按钮 ---------- */
.btn {
  display:inline-flex; align-items:center; gap:9px;
  padding: 13px 26px; border-radius: 999px; font-weight:600; font-size:15px;
  cursor:pointer; border:none; transition: transform .18s, box-shadow .25s, background .25s;
  white-space:nowrap;
}
.btn--primary { background: var(--grad-tech); color:#06121a; box-shadow: 0 10px 24px rgba(0,224,207,.28); }
.btn--primary:hover { transform: translateY(-2px); box-shadow: 0 16px 34px rgba(58,134,255,.34); }
.btn--ghost { background: transparent; color: var(--ink); border:1.5px solid var(--ink); }
.btn--ghost:hover { background: var(--ink); color: var(--paper); }
.btn--light { background: var(--paper-2); color: var(--ink); }
.btn--light:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }

/* ---------- 顶部导航 ---------- */
.nav {
  position: sticky; top:0; z-index: 100;
  background: rgba(246,241,231,.82);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}
.nav__inner { display:flex; align-items:center; justify-content:space-between; height:72px; }
.brand { display:flex; align-items:center; gap:12px; font-family: var(--font-serif); font-weight:700; font-size:22px; color:var(--ink); }
.brand__logo { width:40px; height:40px; }
.brand small { font-family: var(--font-sans); font-size:11px; letter-spacing:.18em; color: var(--tech-blue); display:block; margin-top:-4px; }
.nav__links { display:flex; align-items:center; gap:30px; }
.nav__links a { font-size:15px; color: var(--text); position:relative; padding:6px 0; }
.nav__links a::after { content:""; position:absolute; left:0; bottom:0; width:0; height:2px; background:var(--grad-tech); transition:width .25s; }
.nav__links a:hover::after, .nav__links a.active::after { width:100%; }
.nav__cta { display:flex; gap:12px; align-items:center; }
.nav__toggle { display:none; background:none; border:none; cursor:pointer; padding:8px; }
.nav__toggle span { display:block; width:24px; height:2px; background:var(--ink); margin:5px 0; transition:.3s; }

/* ---------- Hero ---------- */
.hero {
  position:relative; overflow:hidden;
  background: var(--grad-ink);
  color: var(--paper);
  padding: 110px 0 130px;
}
.hero::before {
  content:""; position:absolute; inset:0;
  background:
    radial-gradient(70% 60% at 80% 10%, rgba(0,224,207,.20), transparent 60%),
    radial-gradient(60% 50% at 10% 90%, rgba(58,134,255,.18), transparent 60%),
    radial-gradient(40% 40% at 60% 60%, rgba(201,162,39,.14), transparent 60%);
  pointer-events:none;
}
.hero__grid { display:grid; grid-template-columns: 1.1fr .9fr; gap:50px; align-items:center; position:relative; z-index:2; }
.hero h1 { color: var(--paper); font-size: clamp(34px, 5vw, 58px); margin: 16px 0 22px; letter-spacing:.01em; }
.hero h1 .grad-text { font-family: var(--font-serif); }
.hero p.lead { color: rgba(246,241,231,.78); }
.hero__btns { display:flex; gap:14px; margin-top:32px; flex-wrap:wrap; }
.hero__stats { display:flex; gap:36px; margin-top:44px; flex-wrap:wrap; }
.hero__stats .num { font-family:var(--font-serif); font-size:30px; color: var(--tech-cyan); font-weight:700; }
.hero__stats .lbl { font-size:13px; color: rgba(246,241,231,.6); }
.hero__art { position:relative; }
.hero__art svg { width:100%; height:auto; filter: drop-shadow(0 20px 60px rgba(0,224,207,.18)); }

/* 滚动提示 */
.scroll-hint { position:absolute; bottom:22px; left:50%; transform:translateX(-50%); color:rgba(246,241,231,.5); font-size:12px; letter-spacing:.2em; z-index:2; }

/* ---------- 通用卡片 ---------- */
.card {
  background: var(--paper-2); border:1px solid var(--line);
  border-radius: var(--radius); padding: 28px; transition: transform .25s, box-shadow .25s, border-color .25s;
  position:relative; overflow:hidden;
}
.card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); border-color: transparent; }
.card__icon {
  width:52px; height:52px; border-radius:14px; display:grid; place-items:center;
  background: var(--grad-tech); color:#06121a; margin-bottom:18px; font-size:24px;
}
.grid-3 { display:grid; grid-template-columns: repeat(3,1fr); gap:24px; }
.grid-2 { display:grid; grid-template-columns: repeat(2,1fr); gap:24px; }
.grid-4 { display:grid; grid-template-columns: repeat(4,1fr); gap:20px; }
.section-head { text-align:center; max-width:760px; margin:0 auto 54px; }
.section-head h2 { font-size: clamp(28px,3.4vw,40px); margin-bottom:14px; }
.section-head .lead { margin:0 auto; }

/* ---------- 特性条 ---------- */
.feature-row { display:grid; grid-template-columns: repeat(3,1fr); gap:24px; }
.feature-row .card h3 { font-size:20px; margin-bottom:8px; }

/* ---------- 标签页 ---------- */
.tabs { display:flex; gap:10px; justify-content:center; flex-wrap:wrap; margin-bottom:36px; }
.tab {
  padding:10px 22px; border-radius:999px; border:1.5px solid var(--line);
  background: var(--paper-2); cursor:pointer; font-size:15px; font-weight:600; color:var(--text-2);
  transition:.2s;
}
.tab.active { background: var(--ink); color: var(--paper); border-color: var(--ink); }

/* ---------- 画廊 ---------- */
.gallery-grid { display:grid; grid-template-columns: repeat(3,1fr); gap:22px; }
.work {
  background: var(--paper-2); border:1px solid var(--line); border-radius: var(--radius);
  overflow:hidden; transition: transform .25s, box-shadow .25s; cursor:pointer;
}
.work:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.work__img { aspect-ratio: 4/5; width:100%; position:relative; overflow:hidden; }
.work__img svg { width:100%; height:100%; display:block; }
.work__meta { padding:16px 18px; }
.work__title { font-family:var(--font-serif); font-weight:700; font-size:17px; color:var(--ink); }
.work__sub { font-size:13px; color:var(--text-3); margin-top:3px; display:flex; justify-content:space-between; }
.tag { display:inline-block; font-size:12px; padding:3px 10px; border-radius:999px; background: var(--paper-3); color:var(--text-2); }

/* ---------- 流程 / 全产业链 ---------- */
.chain { display:grid; grid-template-columns: repeat(6,1fr); gap:0; position:relative; }
.chain__step { text-align:center; padding: 0 10px; position:relative; }
.chain__dot {
  width:54px; height:54px; margin:0 auto 16px; border-radius:50%;
  background: var(--grad-ink); color: var(--tech-cyan); display:grid; place-items:center;
  font-family:var(--font-serif); font-weight:700; font-size:20px; position:relative; z-index:2;
  border:2px solid var(--tech-cyan);
}
.chain__step::after {
  content:""; position:absolute; top:27px; left:50%; width:100%; height:2px;
  background: repeating-linear-gradient(90deg, var(--gold) 0 6px, transparent 6px 12px); z-index:1;
}
.chain__step:last-child::after { display:none; }
.chain__title { font-family:var(--font-serif); font-weight:700; font-size:16px; color:var(--ink); }
.chain__desc { font-size:13px; color:var(--text-3); margin-top:6px; }

/* ---------- 数据区（深色） ---------- */
.dark-band { background: var(--grad-ink); color: var(--paper); position:relative; overflow:hidden; }
.dark-band::before {
  content:""; position:absolute; inset:0;
  background: radial-gradient(60% 80% at 85% 20%, rgba(0,224,207,.16), transparent 60%);
}
.dark-band h2, .dark-band h3 { color: var(--paper); }
.dark-band .lead { color: rgba(246,241,231,.72); }
/* 对比度修复：深色区块内若嵌套浅色卡片（.card/.work 背景为宣纸浅色），
   卡片内标题必须恢复墨黑，否则浅白标题压浅底几乎不可见 */
.dark-band .card h2,
.dark-band .card h3,
.dark-band .card h4,
.dark-band .card .work__title { color: var(--ink); }
.dark-band .card .tag { background: var(--paper-3); color: var(--text-2); }

/* ---------- 工具卡片 ---------- */
.tool-card { display:flex; gap:18px; align-items:flex-start; }
.tool-card .card__icon { margin-bottom:0; flex:0 0 auto; }
.tool-card h3 { font-size:18px; }
.tool-card p { font-size:14px; color:var(--text-2); }

/* ---------- 表单 ---------- */
.field { margin-bottom:18px; }
.field label { display:block; font-size:14px; font-weight:600; margin-bottom:7px; color:var(--ink); }
.field input, .field textarea, .field select {
  width:100%; padding:13px 15px; border:1.5px solid var(--line); border-radius: var(--radius-sm);
  font-family: var(--font-sans); font-size:15px; background: var(--paper-2); color:var(--text);
  transition: border-color .2s, box-shadow .2s;
}
.field input:focus, .field textarea:focus, .field select:focus {
  outline:none; border-color: var(--tech-cyan); box-shadow: 0 0 0 3px rgba(0,224,207,.16);
}
.field textarea { resize: vertical; min-height:120px; }

/* ---------- 页脚 ---------- */
.footer { background: var(--ink); color: rgba(246,241,231,.7); padding: 64px 0 28px; }
.footer__grid { display:grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap:40px; }
.footer h4 { color: var(--paper); font-size:16px; margin-bottom:16px; font-family:var(--font-sans); }
.footer a { display:block; font-size:14px; padding:5px 0; color: rgba(246,241,231,.66); transition:color .2s; }
.footer a:hover { color: var(--tech-cyan); }
.footer__brand p { font-size:14px; max-width:320px; margin-top:14px; }
.footer__bottom { border-top:1px solid rgba(246,241,231,.12); margin-top:40px; padding-top:22px; display:flex; justify-content:space-between; flex-wrap:wrap; gap:10px; font-size:13px; color: rgba(246,241,231,.5); }

/* ---------- 演示生成器 ---------- */
.gen-stage {
  background: var(--paper-2); border:1.5px dashed var(--line); border-radius: var(--radius);
  aspect-ratio: 1/1; display:grid; place-items:center; position:relative; overflow:hidden;
}
.gen-stage svg { width:80%; height:80%; }
.gen-loading { position:absolute; inset:0; background:rgba(255,253,248,.85); display:none; place-items:center; }
.gen-loading.show { display:grid; }
.spinner { width:44px; height:44px; border:4px solid var(--line); border-top-color: var(--tech-cyan); border-radius:50%; animation: spin 1s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- 问答库 ---------- */
.faq-wrap { max-width: 900px; margin: 0 auto; }
.faq-item { background: var(--paper-2); border:1px solid var(--line); border-radius: var(--radius-sm); margin-bottom: 12px; transition: box-shadow .2s; }
.faq-item:hover { box-shadow: var(--shadow-sm); }
.faq-q { padding: 16px 20px; font-weight:600; cursor:pointer; display:flex; align-items:flex-start; gap:10px; font-size:15.5px; color:var(--ink); }
.faq-q .qt { flex:1; }
.faq-q::after { content:"+"; color: var(--tech-cyan); font-weight:700; font-size:19px; line-height:1.2; }
.faq-item.open .faq-q::after { content:"\2212"; }
.faq-a { display:none; padding: 14px 20px 18px; color: var(--text-2); font-size:14.5px; line-height:1.85; border-top:1px dashed var(--line); margin: 0 20px; padding-left:0; padding-right:0; }
.faq-item.open .faq-a { display:block; }
.faq-cat { display:inline-block; font-size:12px; padding:2px 9px; border-radius:999px; background:var(--paper-3); color:var(--text-2); margin-right:9px; font-weight:400; white-space:nowrap; }
.faq-search { max-width:520px; margin: 0 auto 26px; display:block; width:100%; padding:13px 18px; border:1.5px solid var(--line); border-radius:999px; font-size:15px; background:var(--paper-2); }
.faq-search:focus { outline:none; border-color:var(--tech-cyan); box-shadow:0 0 0 3px rgba(0,224,207,.15); }
.faq-count { text-align:center; color:var(--text-3); font-size:14px; margin-bottom:20px; }

/* ---------- 价格 ---------- */
.price-card { text-align:center; }
.price-card .price { font-family:var(--font-serif); font-size:40px; color:var(--ink); font-weight:700; }
.price-card .price small { font-size:15px; color:var(--text-3); font-weight:400; }
.price-card ul { text-align:left; margin:18px 0; }
.price-card li { padding:8px 0; border-bottom:1px dashed var(--line); font-size:14px; color:var(--text-2); }
.price-card li::before { content:"✓"; color: var(--tech-cyan); font-weight:700; margin-right:9px; }
.price-card--featured { border:2px solid var(--tech-cyan); box-shadow: var(--shadow-md); }

/* ---------- 动画 ---------- */
.reveal { opacity:0; transform: translateY(28px); transition: opacity .7s ease, transform .7s ease; }
.reveal.in { opacity:1; transform:none; }
@media (prefers-reduced-motion: reduce){ .reveal{ opacity:1; transform:none; } }

/* ---------- 响应式 ---------- */
@media (max-width: 980px) {
  .hero__grid { grid-template-columns:1fr; }
  .hero__art { order:-1; max-width:440px; margin:0 auto; }
  .grid-3, .grid-4 { grid-template-columns: repeat(2,1fr); }
  .feature-row { grid-template-columns:1fr; }
  .chain { grid-template-columns: repeat(3,1fr); row-gap:36px; }
  .chain__step:nth-child(3)::after { display:none; }
  .footer__grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 680px) {
  .nav__links { display:none; position:absolute; top:72px; left:0; right:0; background:var(--paper-2); flex-direction:column; padding:20px; gap:6px; border-bottom:1px solid var(--line); box-shadow:var(--shadow-md); }
  .nav__links.open { display:flex; }
  .nav__cta .btn--light { display:none; }
  .nav__toggle { display:block; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns:1fr; }
  .gallery-grid { grid-template-columns:1fr; }
  .hero { padding:70px 0 90px; }
  .section { padding:60px 0; }
  .footer__grid { grid-template-columns:1fr; }
  .chain { grid-template-columns: repeat(2,1fr); }
  .chain__step::after { display:none; }
}