/* =========================================================
   元启数创AI 官网样式
   - 明暗双主题（data-theme="light" / 默认暗色）
   - 品牌主色：紫(#7c5cff) → 蓝(#5b8cff)
   - 响应式：>=1024 桌面 / 768-1023 平板 / <768 移动
   ========================================================= */

/* ---------- 主题变量（暗色为默认） ---------- */
:root {
  --c-primary: #7c5cff;
  --c-primary-2: #5b8cff;
  --c-primary-soft: rgba(124, 92, 255, 0.16);
  --grad-primary: linear-gradient(135deg, #7c5cff 0%, #5b8cff 100%);
  --grad-text: linear-gradient(120deg, #b39bff 0%, #7c5cff 45%, #5b8cff 100%);

  --c-bg: #0a0818;
  --c-bg-2: #110d24;
  --c-surface: rgba(255, 255, 255, 0.04);
  --c-surface-2: rgba(255, 255, 255, 0.06);
  --c-border: rgba(255, 255, 255, 0.09);
  --c-text: #f2f0fb;
  --c-text-2: #b9b4d4;
  --c-text-3: #8b86a8;
  --c-shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
  --c-header-bg: rgba(10, 8, 24, 0.72);
  --hero-glow: radial-gradient(60% 60% at 70% 20%, rgba(124, 92, 255, 0.35), transparent 70%);
}

:root[data-theme="light"] {
  --c-primary: #6d4bff;
  --c-primary-2: #3f74ff;
  --c-primary-soft: rgba(109, 75, 255, 0.1);
  --grad-primary: linear-gradient(135deg, #6d4bff 0%, #3f74ff 100%);
  --grad-text: linear-gradient(120deg, #6d4bff 0%, #5b6bff 50%, #3f74ff 100%);

  --c-bg: #f7f6fc;
  --c-bg-2: #ffffff;
  --c-surface: #ffffff;
  --c-surface-2: #f2f0fb;
  --c-border: rgba(20, 16, 50, 0.08);
  --c-text: #18142e;
  --c-text-2: #4c4769;
  --c-text-3: #807a99;
  --c-shadow: 0 20px 50px rgba(78, 60, 160, 0.12);
  --c-header-bg: rgba(255, 255, 255, 0.82);
  --hero-glow: radial-gradient(60% 60% at 70% 20%, rgba(124, 92, 255, 0.18), transparent 70%);
}

/* ---------- 基础 ---------- */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 84px; }
body {
  font-family: "PingFang SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Noto Sans CJK SC", sans-serif;
  background: var(--c-bg);
  color: var(--c-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background .4s ease, color .4s ease;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
.container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 24px; }
.container.narrow { max-width: 860px; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-size: 15px; font-weight: 600; line-height: 1;
  padding: 12px 22px; border-radius: 12px; cursor: pointer;
  border: 1px solid transparent; transition: transform .2s ease, box-shadow .25s ease, background .25s ease, opacity .2s;
  white-space: nowrap;
}
.btn:hover { transform: translateY(-2px); }
.btn-lg { padding: 15px 30px; font-size: 16px; }
.btn-block { width: 100%; }
.btn-primary { background: var(--grad-primary); color: #fff; box-shadow: 0 10px 28px rgba(124, 92, 255, 0.4); }
.btn-primary:hover { box-shadow: 0 14px 36px rgba(124, 92, 255, 0.55); }
.btn-ghost { background: var(--c-surface); color: var(--c-text); border-color: var(--c-border); }
.btn-ghost:hover { background: var(--c-surface-2); border-color: var(--c-primary); }

/* ---------- 顶部导航 ---------- */
.site-header {
  position: fixed; inset: 0 0 auto 0; z-index: 100;
  backdrop-filter: blur(18px); -webkit-backdrop-filter: blur(18px);
  background: var(--c-header-bg);
  border-bottom: 1px solid transparent;
  transition: background .3s, border-color .3s, box-shadow .3s;
}
.site-header.scrolled { border-bottom-color: var(--c-border); box-shadow: 0 8px 30px rgba(0,0,0,0.12); }
.nav { display: flex; align-items: center; gap: 24px; height: 72px; }
.brand { display: flex; align-items: center; gap: 12px; flex-shrink: 0; }
.brand-logo { width: 40px; height: 40px; border-radius: 11px; box-shadow: 0 6px 18px rgba(124,92,255,0.4); }
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-name { font-size: 17px; font-weight: 800; letter-spacing: .3px;
  background: var(--grad-text); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.brand-sub { font-size: 11px; color: var(--c-text-3); letter-spacing: 1px; }

.nav-links { display: flex; align-items: center; gap: 28px; margin-left: auto; }
.nav-links a { font-size: 15px; font-weight: 500; color: var(--c-text-2); position: relative; transition: color .2s; }
.nav-links a::after { content: ""; position: absolute; left: 0; bottom: -6px; width: 0; height: 2px; background: var(--grad-primary); transition: width .25s; border-radius: 2px; }
.nav-links a:hover { color: var(--c-text); }
.nav-links a:hover::after { width: 100%; }

.nav-actions { display: flex; align-items: center; gap: 12px; }

/* 语言切换 */
.lang-switch { position: relative; }
.lang-btn { display: inline-flex; align-items: center; gap: 6px; font-size: 14px; color: var(--c-text-2);
  background: transparent; border: 1px solid var(--c-border); border-radius: 10px; padding: 8px 12px; cursor: pointer; transition: all .2s; }
.lang-btn:hover { color: var(--c-text); border-color: var(--c-primary); }
.lang-menu {
  position: absolute; right: 0; top: calc(100% + 8px); min-width: 150px; list-style: none;
  background: var(--c-bg-2); border: 1px solid var(--c-border); border-radius: 12px; padding: 6px;
  box-shadow: var(--c-shadow); opacity: 0; visibility: hidden; transform: translateY(-8px); transition: all .2s; z-index: 50;
}
.lang-menu.open { opacity: 1; visibility: visible; transform: translateY(0); }
.lang-menu li { padding: 9px 12px; border-radius: 8px; font-size: 14px; color: var(--c-text-2); cursor: pointer; transition: all .15s; }
.lang-menu li:hover { background: var(--c-primary-soft); color: var(--c-primary); }
.lang-menu li.active { background: var(--c-primary-soft); color: var(--c-primary); font-weight: 600; }

/* 主题切换 */
.theme-toggle { display: inline-flex; align-items: center; justify-content: center; width: 40px; height: 40px;
  border-radius: 10px; border: 1px solid var(--c-border); background: transparent; color: var(--c-text-2); cursor: pointer; transition: all .2s; }
.theme-toggle:hover { color: var(--c-primary); border-color: var(--c-primary); }
.theme-toggle .icon-moon { display: none; }
:root[data-theme="light"] .theme-toggle .icon-sun { display: none; }
:root[data-theme="light"] .theme-toggle .icon-moon { display: block; }

.menu-toggle { display: none; flex-direction: column; gap: 5px; width: 40px; height: 40px; align-items: center; justify-content: center;
  background: transparent; border: 1px solid var(--c-border); border-radius: 10px; cursor: pointer; }
.menu-toggle span { width: 18px; height: 2px; background: var(--c-text); border-radius: 2px; transition: all .3s; }
.menu-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-toggle.open span:nth-child(2) { opacity: 0; }
.menu-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- 区块通用 ---------- */
.section { padding: 110px 0; }
.section-alt { background: var(--c-bg-2); }
.section-head { text-align: center; max-width: 720px; margin: 0 auto 60px; }
.eyebrow { display: inline-block; font-size: 13px; font-weight: 700; letter-spacing: 2px; text-transform: uppercase;
  color: var(--c-primary); background: var(--c-primary-soft); padding: 6px 14px; border-radius: 999px; margin-bottom: 18px; }
.section-title { font-size: clamp(28px, 4vw, 42px); font-weight: 800; line-height: 1.2; letter-spacing: -.5px; }
.section-sub { margin-top: 16px; font-size: 17px; color: var(--c-text-2); }
.grid { display: grid; gap: 24px; }

.card { background: var(--c-surface); border: 1px solid var(--c-border); border-radius: 18px; transition: transform .3s ease, box-shadow .3s ease, border-color .3s; }

/* ---------- Hero ---------- */
.hero { position: relative; padding: 150px 0 90px; overflow: hidden; }
.hero-glow { position: absolute; inset: 0; background: var(--hero-glow); pointer-events: none; }
.hero-inner { position: relative; display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; }
.badge { display: inline-block; font-size: 13px; font-weight: 600; color: var(--c-primary);
  border: 1px solid var(--c-border); background: var(--c-surface); padding: 7px 16px; border-radius: 999px; margin-bottom: 24px; }
.hero-title { font-size: clamp(34px, 5vw, 58px); font-weight: 900; line-height: 1.12; letter-spacing: -1px; }
.hero-title { background: var(--grad-text); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.hero-desc { margin-top: 22px; font-size: 18px; color: var(--c-text-2); max-width: 520px; }
.hero-cta { margin-top: 34px; display: flex; gap: 16px; flex-wrap: wrap; }
.hero-stats { margin-top: 46px; display: flex; gap: 40px; flex-wrap: wrap; }
.stat { display: flex; flex-direction: column; }
.stat-num, .stat-suffix { font-size: 32px; font-weight: 800; line-height: 1; display: inline; background: var(--grad-text); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.stat-label { margin-top: 8px; font-size: 14px; color: var(--c-text-3); }
.hero-visual img { border-radius: 20px; box-shadow: var(--c-shadow); border: 1px solid var(--c-border); }

/* ---------- 特性网格 ---------- */
.features-grid { grid-template-columns: repeat(3, 1fr); }
.feature-card { padding: 32px 28px; }
.feature-card:hover { transform: translateY(-6px); box-shadow: var(--c-shadow); border-color: var(--c-primary); }
.feat-ico { width: 56px; height: 56px; display: flex; align-items: center; justify-content: center; font-size: 28px;
  border-radius: 15px; margin-bottom: 20px; background: var(--c-primary-soft); }
.feature-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 10px; }
.feature-card p { color: var(--c-text-2); font-size: 15px; }

/* ---------- Split（多模型） ---------- */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.split-media img { border-radius: 20px; box-shadow: var(--c-shadow); border: 1px solid var(--c-border); }
.split-copy .section-title { text-align: left; }
.model-list { list-style: none; margin-top: 28px; display: flex; flex-direction: column; gap: 18px; }
.model-list li { padding-left: 26px; position: relative; }
.model-list li::before { content: ""; position: absolute; left: 0; top: 8px; width: 12px; height: 12px; border-radius: 4px; background: var(--grad-primary); }
.model-list strong { display: block; font-size: 17px; margin-bottom: 2px; }
.model-list span { color: var(--c-text-2); font-size: 15px; }

/* ---------- 流程步骤 ---------- */
.steps-grid { grid-template-columns: repeat(4, 1fr); }
.step { padding: 30px 24px; background: var(--c-surface); border: 1px solid var(--c-border); border-radius: 18px; position: relative; overflow: hidden; transition: transform .3s, border-color .3s; }
.step:hover { transform: translateY(-6px); border-color: var(--c-primary); }
.step-no { font-size: 44px; font-weight: 900; background: var(--grad-text); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; opacity: .8; }
.step h3 { font-size: 18px; margin: 10px 0 8px; }
.step p { color: var(--c-text-2); font-size: 14px; }

/* ---------- 应用场景 ---------- */
.scenarios-grid { grid-template-columns: repeat(2, 1fr); }
.scenario-card { overflow: hidden; }
.scenario-card:hover { transform: translateY(-6px); box-shadow: var(--c-shadow); }
.scenario-img { height: 220px; width: 100%; object-fit: cover; }
.scenario-emoji { height: 220px; display: flex; align-items: center; justify-content: center; font-size: 72px; background: var(--c-primary-soft); }
.scenario-body { padding: 26px 28px; }
.scenario-body h3 { font-size: 21px; margin-bottom: 8px; }
.scenario-body p { color: var(--c-text-2); font-size: 15px; }

/* ---------- 优势 ---------- */
.adv-grid { grid-template-columns: repeat(4, 1fr); }
.adv { text-align: center; padding: 32px 22px; }
.adv-ico { font-size: 40px; margin-bottom: 16px; }
.adv h3 { font-size: 18px; margin-bottom: 8px; }
.adv p { color: var(--c-text-2); font-size: 14px; }

/* ---------- 价格 ---------- */
.pricing-grid { grid-template-columns: repeat(3, 1fr); align-items: stretch; }
.price-card { padding: 38px 30px; display: flex; flex-direction: column; position: relative; }
.price-card:hover { transform: translateY(-6px); box-shadow: var(--c-shadow); }
.price-featured { border-color: var(--c-primary); box-shadow: 0 20px 50px rgba(124,92,255,0.28); }
.price-tag { position: absolute; top: -13px; left: 50%; transform: translateX(-50%); font-size: 12px; font-weight: 700;
  color: #fff; background: var(--grad-primary); padding: 6px 16px; border-radius: 999px; }
.price-name { font-size: 19px; font-weight: 700; }
.price-amt { margin: 18px 0 24px; display: flex; align-items: baseline; gap: 2px; }
.price-cur { font-size: 22px; font-weight: 700; color: var(--c-text-2); }
.price-val { font-size: 48px; font-weight: 900; line-height: 1; }
.price-custom { font-size: 36px; }
.price-per { font-size: 15px; color: var(--c-text-3); margin-left: 4px; }
.price-feats { list-style: none; flex: 1; display: flex; flex-direction: column; gap: 14px; margin-bottom: 28px; }
.price-feats li { position: relative; padding-left: 28px; color: var(--c-text-2); font-size: 15px; }
.price-feats li::before { content: "✓"; position: absolute; left: 0; top: 0; color: var(--c-primary); font-weight: 800; }

/* ---------- FAQ ---------- */
.faq-list { display: flex; flex-direction: column; gap: 14px; }
.faq-item { background: var(--c-surface); border: 1px solid var(--c-border); border-radius: 14px; padding: 4px 24px; transition: border-color .25s; }
.faq-item[open] { border-color: var(--c-primary); }
.faq-item summary { list-style: none; cursor: pointer; padding: 20px 0; font-size: 17px; font-weight: 600; display: flex; justify-content: space-between; align-items: center; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; font-size: 24px; color: var(--c-primary); transition: transform .25s; }
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item p { color: var(--c-text-2); padding: 0 0 22px; font-size: 15px; }

/* ---------- CTA Banner ---------- */
.cta-banner { padding: 100px 0; position: relative; overflow: hidden;
  background: linear-gradient(135deg, rgba(124,92,255,0.16), rgba(91,140,255,0.16)); }
:root[data-theme="light"] .cta-banner { background: linear-gradient(135deg, rgba(124,92,255,0.08), rgba(91,140,255,0.08)); }
.cta-inner { text-align: center; }
.cta-title { font-size: clamp(28px, 4vw, 44px); font-weight: 900; letter-spacing: -.5px; }
.cta-sub { margin-top: 16px; font-size: 18px; color: var(--c-text-2); }
.cta-actions { margin-top: 34px; display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ---------- 页脚 ---------- */
.site-footer { background: var(--c-bg-2); border-top: 1px solid var(--c-border); padding: 64px 0 32px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; }
.footer-brand .brand { margin-bottom: 16px; }
.footer-desc { color: var(--c-text-2); font-size: 14px; max-width: 280px; }
.footer-col h4 { font-size: 15px; margin-bottom: 18px; }
.footer-col a { display: block; color: var(--c-text-2); font-size: 14px; margin-bottom: 12px; transition: color .2s; }
.footer-col a:hover { color: var(--c-primary); }
.footer-bottom { margin-top: 48px; padding-top: 24px; border-top: 1px solid var(--c-border); text-align: center; color: var(--c-text-3); font-size: 13px; line-height: 1.8; }
.footer-records { display: flex; flex-direction: column; align-items: center; gap: 4px; max-width: 960px; margin: 0 auto; }
.footer-records > a { color: inherit; transition: color .2s; }
.footer-records > a:hover { color: var(--c-primary); }

/* ---------- 滚动入场动效 ---------- */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ---------- 响应式 ---------- */
@media (max-width: 1023px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .steps-grid { grid-template-columns: repeat(2, 1fr); }
  .adv-grid { grid-template-columns: repeat(2, 1fr); }
  .hero-inner { grid-template-columns: 1fr; }
  .hero-visual { order: -1; }
  .split { grid-template-columns: 1fr; }
  .split-media { order: -1; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 767px) {
  .section { padding: 72px 0; }
  .hero { padding: 120px 0 60px; }
  .nav-links { position: fixed; inset: 72px 0 auto 0; flex-direction: column; align-items: stretch; gap: 0;
    background: var(--c-bg-2); border-bottom: 1px solid var(--c-border); padding: 12px 24px;
    transform: translateY(-130%); transition: transform .35s ease; box-shadow: var(--c-shadow); }
  .nav-links.open { transform: translateY(0); }
  .nav-links a { padding: 14px 0; border-bottom: 1px solid var(--c-border); }
  .nav-links a::after { display: none; }
  .nav-cta { display: none; }
  .menu-toggle { display: flex; }
  .features-grid, .steps-grid, .adv-grid, .scenarios-grid, .pricing-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .hero-stats { gap: 28px; }
  .stat-num, .stat-suffix { font-size: 26px; }
  .brand-sub { display: none; }
}