:root {
  --blue: #0052d9; --blue-d: #003ba3; --ink: #1d2129; --muted: #86909c;
  --line: #e7eaf0; --bg: #fff;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { font-family: "PingFang SC", "Microsoft YaHei", system-ui, sans-serif; color: var(--ink); background: var(--bg); }
a { text-decoration: none; color: inherit; }
.wrap { max-width: 1160px; margin: 0 auto; padding: 0 20px; }

/* 导航 */
.nav { position: sticky; top: 0; z-index: 100; background: rgba(255,255,255,.92); backdrop-filter: blur(10px); border-bottom: 1px solid var(--line); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 62px; }
.brand { display: flex; align-items: center; gap: 10px; }
.brand b { font-size: 18px; color: var(--blue-d); letter-spacing: .2px; }
.brand em { display: block; font-style: normal; font-size: 11px; color: var(--muted); }
.nav-links { display: flex; gap: 30px; font-size: 14px; }
.nav-links a:hover { color: var(--blue); }
.nav-cta { display: flex; gap: 10px; }

/* 按钮 */
.btn { display: inline-flex; align-items: center; justify-content: center; border-radius: 22px; padding: 9px 22px; font-size: 14px; cursor: pointer; transition: all .18s; border: 1px solid transparent; }
.btn.solid { background: var(--blue); color: #fff; }
.btn.solid:hover { background: var(--blue-d); }
.btn.ghost { border-color: #c9d4ea; color: var(--blue); background: transparent; }
.btn.ghost:hover { border-color: var(--blue); }
.btn.big { padding: 13px 32px; font-size: 15px; }
.btn.ghost-blue { border-color: #c9d4ea; color: var(--blue); }
.btn.ghost-blue:hover { background: #f0f5ff; }

/* Hero */
.hero { background: radial-gradient(1100px 520px at 18% -20%, #2e63f0 0%, #0a2c7e 48%, #061a54 100%); color: #fff; overflow: hidden; }
.hero-inner { display: grid; grid-template-columns: 1.15fr 1fr; gap: 30px; align-items: center; padding-top: 74px; padding-bottom: 84px; }
.hero h1 { font-size: 42px; line-height: 1.3; font-weight: 700; }
.hero h1 span { background: linear-gradient(90deg, #9ec2ff, #4de1ff); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero p { margin-top: 18px; font-size: 16px; line-height: 1.9; color: #c9d8ff; }
.hero-btns { margin-top: 30px; display: flex; gap: 14px; }
.hero .btn.ghost { border-color: rgba(255,255,255,.4); color: #fff; }
.hero .btn.ghost:hover { border-color: #fff; }
.hero-tags { margin-top: 26px; display: flex; gap: 22px; font-size: 13px; color: #9db9f5; flex-wrap: wrap; }

/* 数据条 */
.stats { background: #fff; box-shadow: 0 12px 30px rgba(10,40,120,.08); position: relative; z-index: 5; }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); padding: 26px 20px; gap: 10px; }
.stats-grid div { text-align: center; border-right: 1px dashed var(--line); }
.stats-grid div:last-child { border: none; }
.stats-grid b { display: block; font-size: 26px; color: var(--blue-d); }
.stats-grid span { font-size: 13px; color: var(--muted); }

/* 通用区块 */
.sec { padding: 74px 0; }
.sec-blue { background: linear-gradient(180deg, #f4f8ff, #eef3ff); }
.sec-gray { background: #f7f9fc; }
.sec-title { text-align: center; font-size: 30px; }
.sec-title em { display: block; font-style: normal; font-size: 13px; color: var(--muted); margin-top: 6px; font-weight: 400; }
.sec-sub { text-align: center; color: #4e5969; margin: 14px auto 40px; max-width: 640px; line-height: 1.8; }
.sec-title.left, .sec-sub.left { text-align: left; }

/* 特性 */
.feat-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.feat { background: #fff; border: 1px solid var(--line); border-radius: 12px; padding: 26px 22px; transition: all .2s; }
.feat:hover { transform: translateY(-4px); box-shadow: 0 14px 34px rgba(10,40,120,.1); }
.feat svg { width: 34px; height: 34px; color: var(--blue); margin-bottom: 14px; }
.feat b { display: block; font-size: 16px; margin-bottom: 8px; }
.feat p { font-size: 13px; color: var(--muted); line-height: 1.8; }

/* AI 区块 */
.ai-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 44px; align-items: center; }
.ai-list { list-style: none; margin: 6px 0 28px; }
.ai-list li { display: flex; align-items: center; gap: 10px; padding: 8px 0; font-size: 14px; color: #363e4d; }
.ai-list svg { width: 18px; height: 18px; color: var(--blue); flex: none; }
.ai-code { background: #0d1b3d; border-radius: 14px; padding: 0 0 18px; box-shadow: 0 24px 60px rgba(6,26,84,.35); overflow: hidden; }
.code-head { display: flex; align-items: center; gap: 7px; padding: 13px 16px; border-bottom: 1px solid rgba(255,255,255,.08); }
.code-head i { width: 11px; height: 11px; border-radius: 50%; background: #ff5f57; }
.code-head i:nth-child(2) { background: #febc2e; }
.code-head i:nth-child(3) { background: #28c840; }
.code-head span { margin-left: 8px; color: #8ea6d8; font-size: 12px; }
.ai-code pre { padding: 18px 20px 6px; overflow-x: auto; }
.ai-code code { font-family: ui-monospace, Consolas, monospace; font-size: 12.5px; line-height: 1.75; color: #dbe7ff; }
.ai-code .c { color: #6b83b8; }
.ai-code .k { color: #7dd3fc; }
.ai-code .s { color: #a5e88b; }
.model-chips { display: flex; flex-wrap: wrap; gap: 8px; padding: 12px 20px 0; }
.model-chips span { font-size: 12px; color: #9ec2ff; border: 1px solid rgba(126,155,229,.4); border-radius: 14px; padding: 4px 12px; }

/* 定价 */
.price-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.price-card { position: relative; background: #fff; border: 1.5px solid var(--line); border-radius: 14px; padding: 28px 24px; text-align: center; transition: all .2s; }
.price-card:hover { transform: translateY(-4px); box-shadow: 0 16px 40px rgba(10,40,120,.12); }
.price-card.hot { border-color: var(--blue); box-shadow: 0 16px 40px rgba(0,82,217,.15); }
.price-card .tag { position: absolute; top: -11px; left: 50%; transform: translateX(-50%); background: #eef3ff; color: var(--blue); font-size: 12px; border-radius: 12px; padding: 3px 14px; }
.price-card.hot .tag { background: var(--blue); color: #fff; }
.price-card h5 { font-size: 16px; margin-bottom: 12px; }
.price-card .p { color: #e34d59; font-weight: 700; font-size: 40px; }
.price-card .p small { font-size: 16px; }
.price-card .p span { font-size: 14px; color: var(--muted); font-weight: 400; }
.price-card ul { list-style: none; margin: 18px 0 22px; text-align: left; }
.price-card li { font-size: 13px; color: #4e5969; padding: 6px 0; border-bottom: 1px dashed #f0f2f7; }
.price-card .btn { width: 100%; }

/* 底部 */
.footer { background: #0c1526; color: #b7c3d6; padding: 54px 0 0; margin-top: 20px; }
.foot-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 30px; padding-bottom: 36px; }
.foot-grid b { color: #fff; display: block; margin-bottom: 12px; font-size: 14px; }
.foot-grid a { display: block; font-size: 13px; color: #8fa0bb; padding: 4px 0; }
.foot-grid a:hover { color: #fff; }
.brand.light b { color: #fff; }
.foot-bar { display: flex; justify-content: space-between; padding: 16px 20px; border-top: 1px solid rgba(255,255,255,.08); font-size: 12px; color: #6d7f9c; }

@media (max-width: 900px) {
  .hero-inner, .ai-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 30px; }
  .feat-grid, .price-grid { grid-template-columns: repeat(2, 1fr); }
  .foot-grid { grid-template-columns: 1fr 1fr; }
  .nav-links { display: none; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-grid div { border: none; }
}

/* ===== V2：公告条 / FAQ / 接入指南 / AI 客服 / 动效 ===== */
.notice-bar { background: linear-gradient(90deg, #0052d9, #2668ff); color: #fff; font-size: 13px; text-align: center; padding: 8px 16px; cursor: pointer; }
.notice-bar b { margin-right: 8px; }

.faq-list { max-width: 780px; margin: 0 auto; }
.faq-item { background: #fff; border: 1px solid var(--line); border-radius: 12px; margin-bottom: 12px; overflow: hidden; transition: box-shadow .2s; }
.faq-item[open] { box-shadow: 0 10px 30px rgba(10,40,120,.08); }
.faq-item summary { list-style: none; cursor: pointer; padding: 18px 22px; font-weight: 600; font-size: 15px; display: flex; align-items: center; gap: 10px; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::before { content: '?'; flex: none; width: 22px; height: 22px; border-radius: 50%; background: #eef3ff; color: var(--blue); font-size: 13px; display: inline-flex; align-items: center; justify-content: center; }
.faq-item[open] summary::before { background: var(--blue); color: #fff; }
.faq-item .faq-body { padding: 0 22px 20px 54px; color: #4e5969; font-size: 14px; line-height: 1.9; white-space: pre-line; }

.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; max-width: 980px; margin: 0 auto 34px; }
.step { background: #fff; border: 1px solid var(--line); border-radius: 12px; padding: 22px; text-align: center; }
.step .num { width: 34px; height: 34px; border-radius: 50%; background: var(--blue); color: #fff; font-weight: 700; display: inline-flex; align-items: center; justify-content: center; margin-bottom: 12px; }
.step b { display: block; margin-bottom: 6px; }
.step p { font-size: 13px; color: var(--muted); line-height: 1.8; }
.step code { background: #f2f6ff; color: var(--blue-d); padding: 2px 8px; border-radius: 5px; font-size: 12px; }

/* 滚动显现动效 */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }

/* AI 客服（官网游客版） */
.sw-root { position: fixed; right: 22px; bottom: 22px; z-index: 3000; font-family: "PingFang SC","Microsoft YaHei",system-ui,sans-serif; }
.sw-fab { width: 56px; height: 56px; border-radius: 50%; border: none; cursor: pointer;
  background: linear-gradient(135deg, #2668ff, #0052d9); box-shadow: 0 10px 26px rgba(0,60,180,.45);
  display: flex; align-items: center; justify-content: center; transition: transform .2s; }
.sw-fab:hover { transform: scale(1.08); }
.sw-panel { position: absolute; right: 0; bottom: 68px; width: 360px; height: 520px; max-height: calc(100vh - 120px);
  background: #fff; border-radius: 16px; box-shadow: 0 24px 70px rgba(6,26,84,.3); display: flex; flex-direction: column; overflow: hidden; }
.sw-panel.show { display: flex; }
.sw-head { background: linear-gradient(120deg, #0052d9, #2668ff); color: #fff; padding: 14px 16px; display: flex; align-items: center; gap: 10px; }
.sw-head b { font-size: 15px; display: block; }
.sw-head span { font-size: 12px; opacity: .85; display: flex; align-items: center; gap: 5px; }
.sw-head .dot { width: 7px; height: 7px; border-radius: 50%; background: #52ff9c; display: inline-block; }
.sw-close { margin-left: auto; background: transparent; border: none; color: #fff; font-size: 15px; cursor: pointer; opacity: .8; }
.sw-body { flex: 1; overflow-y: auto; padding: 14px; background: #f6f8fc; }
.sw-msg { display: flex; margin-bottom: 10px; }
.sw-msg.user { justify-content: flex-end; }
.sw-bubble { max-width: 82%; padding: 9px 12px; border-radius: 12px; font-size: 13px; line-height: 1.65; white-space: pre-wrap; word-break: break-word; }
.sw-msg.assistant .sw-bubble { background: #fff; color: #1d2129; border: 1px solid #e9edf5; border-top-left-radius: 4px; box-shadow: 0 2px 8px rgba(10,40,120,.05); }
.sw-msg.user .sw-bubble { background: linear-gradient(120deg, #2668ff, #0052d9); color: #fff; border-top-right-radius: 4px; }
.sw-bubble .cursor { animation: swblink .8s infinite; }
@keyframes swblink { 50% { opacity: 0; } }
.sw-quick { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 6px; }
.sw-quick span { font-size: 12px; color: #0052d9; background: #eef3ff; border: 1px solid #c9d9ff; padding: 5px 12px; border-radius: 14px; cursor: pointer; }
.sw-quick span:hover { background: #dfe9ff; }
.sw-foot { display: flex; gap: 8px; padding: 12px; border-top: 1px solid #eef1f6; background: #fff; }
.sw-foot input { flex: 1; border: 1px solid #dfe3ec; border-radius: 10px; padding: 9px 12px; font-size: 13px; outline: none; }
.sw-foot input:focus { border-color: #2668ff; }
.sw-foot button { border: none; background: linear-gradient(120deg, #2668ff, #0052d9); color: #fff; border-radius: 10px; padding: 0 18px; cursor: pointer; font-size: 13px; }
.sw-foot button:disabled { opacity: .5; cursor: not-allowed; }
.sw-tip { text-align: center; font-size: 11px; color: #a0a6b3; padding: 0 0 10px; background: #fff; }
.sw-tip a { color: #0052d9; cursor: pointer; }
.sw-msg.assistant .sw-bubble a { color: #0052d9; }

/* ================= V3 细节美化 ================= */
.nav { transition: box-shadow .3s ease, background .3s ease; }
.nav.scrolled { box-shadow: 0 10px 34px rgba(10,40,120,.12); background: rgba(255,255,255,.97); }
.btn.solid { box-shadow: 0 8px 22px rgba(0,82,217,.32); }
.btn.solid:hover { transform: translateY(-2px); }
.btn.ghost:hover { transform: translateY(-2px); }
.btn { transition: all .2s ease; }

/* Hero 插画漂浮 */
@media (min-width: 900px) {
  .hero-art { animation: floaty 7s ease-in-out infinite; }
}
@keyframes floaty { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-14px); } }

/* 推荐套餐呼吸光圈 */
.price-card.hot .tag { animation: pulse 2.4s infinite; }
@keyframes pulse { 0%, 100% { box-shadow: 0 0 0 0 rgba(0,82,217,.35); } 70% { box-shadow: 0 0 0 12px rgba(0,82,217,0); } }

/* 特性图标底衬 */
.feat svg { filter: drop-shadow(0 4px 10px rgba(0,82,217,.25)); }

/* 数据条数字渐变 */
.stats-grid b { background: linear-gradient(120deg, #0052d9, #26a4ff); -webkit-background-clip: text; background-clip: text; color: transparent; }

/* 代码块光晕 */
.ai-code { position: relative; }
.ai-code::after { content: ""; position: absolute; inset: 0; border-radius: 14px; pointer-events: none;
  box-shadow: inset 0 1px 0 rgba(255,255,255,.08); }

/* FAQ 展开动效 */
.faq-item .faq-body { animation: faqIn .3s ease; }
@keyframes faqIn { from { opacity: 0; transform: translateY(-6px); } to { opacity: 1; transform: none; } }

/* 页脚链接 */
.foot-grid a { transition: color .15s, transform .15s; display: inline-block; }
.foot-grid a:hover { transform: translateX(3px); }

/* 客服按钮光圈 */
.sw-fab { position: relative; }
.sw-fab::after { content: ""; position: absolute; inset: -6px; border-radius: 50%;
  border: 2px solid rgba(47,109,255,.35); animation: fabRing 2.4s ease-out infinite; }
@keyframes fabRing { 0% { transform: scale(.8); opacity: 1; } 100% { transform: scale(1.35); opacity: 0; } }