:root { --ink:#142034; --muted:#647188; --line:#dde4ef; --paper:#f7f9fc; --blue:#1e4bd8; --blue-dark:#15399f; --yellow:#ffcf5c; --white:#fff; }
* { box-sizing:border-box; }
html { scroll-behavior:smooth; }
body { margin:0; background:var(--paper); color:var(--ink); font-family:Inter,ui-sans-serif,system-ui,-apple-system,"PingFang SC","Microsoft YaHei",sans-serif; }
a { color:inherit; text-decoration:none; }
.wrap { max-width:1160px; margin:0 auto; padding:0 24px; }
header { position:relative; z-index:10; background:var(--white); border-bottom:1px solid var(--line); }
.topbar { min-height:76px; display:flex; align-items:center; justify-content:space-between; gap:18px; }
.brand { display:flex; align-items:center; font-size:1.15rem; font-weight:850; letter-spacing:-.04em; }
.brand-mark { display:grid; place-items:center; width:36px; height:36px; margin-right:10px; color:#fff; background:var(--blue); border-radius:11px; font-size:1.15rem; box-shadow:4px 4px 0 #c7d4ff; }
nav { display:flex; gap:22px; font-size:.92rem; font-weight:650; color:#4f5e74; }
nav a:hover { color:var(--blue); }
.site-nav { align-items:center; }
.nav-group { position:relative; }
.nav-group summary { list-style:none; cursor:pointer; }
.nav-group summary::-webkit-details-marker { display:none; }
.nav-group[open] summary,.nav-group summary:hover { color:var(--blue); }
.nav-group summary span { display:inline-block; transition:transform .18s; }
.nav-group[open] summary span { transform:rotate(180deg); }
.nav-submenu { position:absolute; top:calc(100% + 15px); left:-14px; z-index:30; min-width:164px; padding:7px; border:1px solid var(--line); border-radius:13px; background:#fff; box-shadow:0 14px 32px rgba(24,43,80,.14); }
.nav-submenu a { display:block; padding:11px 12px; border-radius:8px; white-space:nowrap; }
.nav-submenu a:hover,.nav-submenu a[aria-current="page"] { background:#eff3ff; color:var(--blue); }
.notice { border-bottom:1px solid var(--line); background:#eef3ff; color:#345090; font-size:.82rem; text-align:center; padding:9px 18px; }
main { padding:48px 0 70px; }
.intro { display:grid; grid-template-columns:1.12fr .88fr; gap:38px; align-items:end; margin-bottom:36px; }
h1 { margin:0 0 14px; max-width:700px; font-size:clamp(2.15rem,6vw,4.35rem); line-height:1.02; letter-spacing:-.07em; }
h1 em { font-style:normal; color:var(--blue); }
.intro p { max-width:600px; margin:0; color:var(--muted); font-size:1.02rem; line-height:1.75; }
.hero-actions { display:flex; flex-wrap:wrap; gap:11px; margin-top:24px; }
.hero-actions a { display:inline-flex; align-items:center; min-height:43px; padding:0 17px; border-radius:11px; font-size:.88rem; font-weight:750; transition:transform .18s,box-shadow .18s; }
.hero-actions a:hover { transform:translateY(-2px); }
.hero-primary { background:var(--blue); color:#fff; box-shadow:3px 3px 0 #c7d4ff; }
.hero-secondary { border:1px solid var(--line); background:#fff; color:#3d527d; }
.notebook { position:relative; min-height:150px; padding:23px 25px 22px 37px; overflow:hidden; border:1px solid #d4dff8; border-radius:16px; background:#fff; box-shadow:10px 10px 0 #e1eaff; transform:rotate(1.3deg); }
.notebook:before { content:""; position:absolute; left:19px; top:0; bottom:0; width:2px; background:#ffcf5c; }
.notebook:after { content:""; position:absolute; inset:25px 0 0 0; background:repeating-linear-gradient(to bottom, transparent 0 23px, #e8eef8 24px 25px); pointer-events:none; }
.notebook strong,.notebook span { position:relative; z-index:1; display:block; }
.notebook strong { font-size:1.05rem; margin-bottom:21px; }
.notebook span { color:#58667b; font-size:.88rem; }
.search-panel { display:grid; grid-template-columns:1fr auto; gap:14px; padding:14px; margin-bottom:28px; background:var(--white); border:1px solid var(--line); border-radius:18px; box-shadow:0 12px 32px rgba(24,43,80,.06); }
.search { display:flex; align-items:center; gap:10px; min-width:0; padding:0 12px; }
.search svg { flex:none; color:#8492aa; }
input { width:100%; padding:10px 0; border:0; outline:0; color:var(--ink); font:inherit; font-size:1rem; }
input::placeholder { color:#95a1b5; }
.count { align-self:center; padding:9px 13px; border-radius:10px; background:#edf2ff; color:#4160a8; white-space:nowrap; font-size:.83rem; font-weight:700; }
.filters { display:flex; flex-wrap:wrap; gap:9px; margin-bottom:27px; }
.filter { padding:9px 14px; border:1px solid var(--line); border-radius:999px; background:var(--white); color:#5c6a80; cursor:pointer; font:inherit; font-size:.88rem; font-weight:700; transition:.18s; }
.filter:hover,.filter.active { color:#fff; border-color:var(--blue); background:var(--blue); }
.section-head { display:flex; align-items:baseline; justify-content:space-between; margin:0 0 15px; }
.section-head h2 { margin:0; font-size:1.12rem; letter-spacing:-.03em; }
.section-head span { color:#8390a4; font-size:.8rem; }
.grid { display:grid; grid-template-columns:repeat(3,1fr); gap:15px; }
.card { position:relative; display:flex; flex-direction:column; min-height:222px; padding:20px; border:1px solid var(--line); border-radius:16px; background:var(--white); transition:transform .18s,box-shadow .18s,border-color .18s; }
.card:hover { border-color:#b8c8f5; box-shadow:0 10px 26px rgba(26,57,120,.10); transform:translateY(-3px); }
.card-top { display:flex; align-items:center; justify-content:space-between; gap:10px; }
.icon { display:grid; place-items:center; width:40px; height:40px; border-radius:12px; background:#eff3ff; color:#214ccb; font-size:1.22rem; }
.tag { padding:5px 8px; border-radius:7px; background:#f2f5f9; color:#718099; font-size:.72rem; font-weight:750; }
.card h3 { margin:18px 0 7px; font-size:1.1rem; letter-spacing:-.025em; }
.card p { margin:0; color:var(--muted); font-size:.88rem; line-height:1.65; }
.card footer { display:flex; align-items:center; justify-content:space-between; gap:8px; margin-top:auto; padding-top:18px; color:#52617a; font-size:.78rem; }
.go { color:var(--blue); font-weight:780; }
.go:after { content:" ↗"; }
.empty { display:none; padding:38px; border:1px dashed #c4cfdf; border-radius:16px; text-align:center; color:#68768b; background:#fff; }
.rule { display:grid; grid-template-columns:auto 1fr; gap:13px; margin-top:38px; padding:19px 20px; border-radius:15px; background:#172642; color:#dce5f6; }
.rule b { color:var(--yellow); }
.rule p { margin:0; color:#c7d2e8; font-size:.86rem; line-height:1.7; }
footer.site-footer { margin-top:32px; color:#77849a; font-size:.8rem; text-align:center; }
.footer-meta { display:flex; flex-wrap:wrap; justify-content:center; align-items:center; gap:8px 20px; padding:17px 0 10px; border-top:1px solid var(--line); }
.footer-meta a,.back-link a { color:var(--blue); font-weight:700; }
.footer-meta a:hover,.back-link a:hover { color:var(--blue-dark); text-decoration:underline; }
.author-slot { display:inline-block; width:90px; min-height:1em; vertical-align:middle; border-bottom:1px solid #aeb9ca; }
.footer-copy { padding-bottom:4px; }
.updates-main { min-height:calc(100vh - 190px); }
.updates-intro { padding:55px 0 30px; }
.updates-intro .eyebrow { margin:0 0 10px; color:var(--blue); font-size:.76rem; font-weight:800; letter-spacing:.16em; }
.updates-intro h1 { margin:0 0 12px; font-size:clamp(2rem,5vw,3.25rem); letter-spacing:-.055em; }
.updates-intro > p:last-child { margin:0; color:var(--muted); line-height:1.7; }
.changelog { max-width:850px; }
.log-item { display:grid; grid-template-columns:135px 1fr; gap:22px; padding:25px 0; border-top:1px solid var(--line); }
.log-date { padding-top:5px; color:#8490a4; font-size:.87rem; }
.log-heading { display:flex; align-items:center; gap:10px; }
.log-heading h2 { margin:0; font-size:1.3rem; letter-spacing:-.03em; }
.latest-tag,.release-tag { padding:4px 8px; border-radius:999px; background:#edf2ff; color:#4160a8; font-size:.72rem; font-weight:750; }
.release-tag { background:#f1f3f6; color:#738097; }
.log-content ul { margin:14px 0 0; padding-left:20px; color:#5d6b80; line-height:1.9; }
.back-link { margin:25px 0 0; }
nav a[aria-current="page"] { color:var(--blue); }
@media (max-width:760px) { .wrap{padding:0 16px} .topbar{min-height:64px;flex-wrap:wrap;padding-top:11px;padding-bottom:11px;gap:10px} .site-nav{display:flex;width:100%;justify-content:space-between;gap:10px;font-size:.86rem} .nav-submenu{left:auto;right:0;top:calc(100% + 9px)} main{padding-top:32px} .intro{grid-template-columns:1fr;gap:23px}.notebook{min-height:120px}.grid{grid-template-columns:1fr}.search-panel{grid-template-columns:1fr}.count{justify-self:start}.card{min-height:194px} }
@media (max-width:600px) { .log-item { grid-template-columns:1fr; gap:8px; } .log-date { padding:0; } .footer-meta { gap:8px 14px; } }

/* 独立的 AI 学习页面 */
.chat-page { padding-top:25px; }
.chat-page-intro { display:flex; align-items:end; justify-content:space-between; gap:20px; margin:0 0 28px; }
.chat-page-intro h1 { max-width:none; margin:9px 0 10px; font-size:clamp(1.9rem,4vw,3.4rem); line-height:1.18; }
.chat-page-intro p { margin:0; color:var(--muted); line-height:1.7; }
.chat-page-intro > a { flex:none; padding:12px 15px; border-radius:11px; font-size:.86rem; font-weight:750; }
.book-crumb { display:flex; align-items:center; gap:9px; margin-bottom:22px; color:#8390a4; font-size:.82rem; }
.chat-page .site-footer { margin-top:50px; }
@media (max-width:600px) { .chat-page-intro { display:block; } .chat-page-intro > a { display:inline-block; margin-top:16px; } }

/* 登录/注册界面预览 */
.login-nav { padding:8px 13px; border:1px solid #d4def6; border-radius:9px; color:var(--blue)!important; background:#f3f6ff; }
.login-main { padding-top:25px; }
.login-layout { display:grid; grid-template-columns:1fr minmax(320px,.78fr); align-items:center; gap:clamp(30px,7vw,90px); min-height:570px; padding:25px 0 40px; }
.login-copy h1 { max-width:660px; margin:12px 0 18px; font-size:clamp(2.25rem,5.5vw,4.1rem); line-height:1.12; }
.login-copy h1 em { font-style:normal; color:var(--blue); }
.login-copy > p { max-width:480px; color:var(--muted); font-size:1rem; line-height:1.8; }
.login-benefits { display:grid; gap:12px; margin-top:29px; color:#536683; font-size:.9rem; }
.login-benefits span::first-letter { color:#21966a; }
.login-card { padding:29px; border:1px solid var(--line); border-radius:20px; background:#fff; box-shadow:0 18px 45px rgba(24,43,80,.08); }
.login-card-head { display:flex; align-items:center; justify-content:space-between; }
.login-card-head h2 { margin:8px 0 0; font-size:1.55rem; }
.login-mark { display:grid; place-items:center; width:43px; height:43px; border-radius:13px; background:#eff3ff; color:var(--blue); font-size:1.45rem; font-weight:800; }
.login-tabs { display:grid; grid-template-columns:1fr 1fr; gap:4px; margin:23px 0 20px; padding:4px; border-radius:11px; background:#f2f5fa; }
.login-tab { padding:9px; border:0; border-radius:8px; background:transparent; color:#6b7890; font:inherit; font-size:.88rem; font-weight:700; cursor:pointer; }
.login-tab.active { background:#fff; color:var(--blue); box-shadow:0 2px 7px rgba(24,43,80,.09); }
#login-form { display:grid; gap:9px; }
#login-form > label,.confirm-wrap > label,.password-label > label { color:#35445b; font-size:.82rem; font-weight:750; }
#login-form input { width:100%; min-width:0; padding:12px 13px; border:1px solid var(--line); border-radius:10px; background:#fff; color:var(--ink); font:inherit; font-size:.9rem; outline:0; }
#login-form input:focus { border-color:#9db2f2; box-shadow:0 0 0 3px #eff3ff; }
.password-label { display:flex; align-items:center; justify-content:space-between; margin-top:6px; }
.password-label button { border:0; background:none; color:var(--blue); font:inherit; font-size:.77rem; cursor:pointer; }
.password-wrap { position:relative; }
.password-wrap input { padding-right:58px!important; }
#toggle-password { position:absolute; top:50%; right:12px; transform:translateY(-50%); border:0; background:transparent; color:#6e7c93; font:inherit; font-size:.76rem; cursor:pointer; }
.confirm-wrap { display:grid; gap:8px; }
.confirm-wrap[hidden],#forgot-password[hidden] { display:none; }
.login-submit { margin-top:9px; padding:12px; border:0; border-radius:10px; background:var(--blue); color:#fff; font:inherit; font-size:.9rem; font-weight:800; cursor:pointer; box-shadow:3px 3px 0 #c7d4ff; }
.login-submit:hover { background:var(--blue-dark); }
.prototype-note { margin:5px 0 0; padding:10px 11px; border-radius:9px; background:#fff7e7; color:#7d6326; font-size:.76rem; line-height:1.65; }
.login-footnote { margin:17px 0 0; color:#8a96a8; font-size:.75rem; line-height:1.7; }
.login-main .site-footer { margin-top:20px; }
@media (max-width:760px) { .login-layout { grid-template-columns:1fr; gap:28px; min-height:0; padding:16px 0 35px; } .login-copy h1 { font-size:clamp(2.1rem,9vw,3rem); } .login-benefits { grid-template-columns:1fr 1fr; gap:9px; font-size:.79rem; } .login-card { width:100%; max-width:480px; margin:0 auto; padding:23px; } .login-nav { padding:6px 9px; } }
@media (max-width:380px) { .login-benefits { grid-template-columns:1fr; } .login-card { padding:19px; } }

/* v2.0.0：收藏、账号状态与二级页面 */
.home-main { padding-top:32px; }
.home-hero { min-height:340px; margin-bottom:34px; }
.home-features { display:grid; grid-template-columns:repeat(3,1fr); gap:15px; }
.home-feature { display:flex; flex-direction:column; min-height:225px; padding:22px; border:1px solid var(--line); border-radius:17px; background:#fff; transition:transform .18s,box-shadow .18s; }
.home-feature:hover { transform:translateY(-3px); box-shadow:0 10px 28px rgba(24,43,80,.09); }
.feature-icon { display:grid; place-items:center; width:45px; height:45px; margin-bottom:16px; border-radius:13px; background:#eff3ff; color:var(--blue); font-size:1.3rem; }
.home-feature h2 { margin:7px 0; font-size:1.25rem; }
.home-feature p { margin:0 0 18px; color:var(--muted); font-size:.9rem; line-height:1.7; }
.feature-link { margin-top:auto; color:var(--blue); font-size:.86rem; font-weight:800; }
.home-status { margin-top:22px!important; }
.cloud-status { margin:14px 0; padding:10px 13px; border:1px solid #dce6fb; border-radius:10px; background:#f1f5ff; color:#49618f; font-size:.82rem; line-height:1.5; }
.cloud-status.is-online { border-color:#c5ead7; background:#effaf4; color:#277449; }
.cloud-status.is-error { border-color:#f0d2c9; background:#fff5f1; color:#984c36; }
.tool-mode { display:flex; gap:6px; padding:4px; border-radius:10px; background:#eef2f8; }
.tool-mode-btn { padding:7px 11px; border:0; border-radius:7px; background:transparent; color:#67758c; font:inherit; font-size:.78rem; font-weight:750; cursor:pointer; }
.tool-mode-btn.active { background:#fff; color:var(--blue); box-shadow:0 1px 5px rgba(24,43,80,.1); }
.card[hidden] { display:none!important; }
.card-top { flex-wrap:wrap; }
.favorite-btn { padding:6px 8px; border:1px solid #d8e1f2; border-radius:8px; background:#fff; color:#536581; font:inherit; font-size:.72rem; font-weight:750; cursor:pointer; }
.favorite-btn[aria-pressed="true"] { border-color:#f2d988; background:#fff9e6; color:#87640d; }
.card .go { display:inline-flex; }
.chat-workspace { display:grid; grid-template-columns:245px minmax(0,1fr); gap:18px; align-items:start; }
.chat-workspace>#chat { min-width:0; }
.chat-sessions { position:sticky; top:14px; padding:15px; border:1px solid var(--line); border-radius:15px; background:#fff; }
.new-chat-btn { width:100%; min-height:41px; padding:8px 12px; font:inherit; font-size:.85rem; }
.session-heading { display:flex; flex-direction:column; gap:4px; margin:18px 0 10px; }
.session-heading h2 { margin:0; font-size:.98rem; }
.session-heading span,.session-help { color:#8490a4; font-size:.72rem; line-height:1.55; }
.chat-session-list { display:grid; gap:6px; max-height:48vh; overflow:auto; }
.chat-session-item { overflow:hidden; padding:9px 10px; border:1px solid transparent; border-radius:8px; background:#f6f8fb; color:#53627a; text-align:left; text-overflow:ellipsis; white-space:nowrap; font:inherit; font-size:.8rem; cursor:pointer; }
.chat-session-item:hover,.chat-session-item.active { border-color:#cbd8fb; background:#eff3ff; color:var(--blue); }
.session-empty { margin:5px 2px; color:#8793a5; font-size:.77rem; line-height:1.6; }
.session-help { margin:12px 0 0; }
.msg-image-omitted { display:block; margin-top:7px; color:#9aa6b8; font-size:.74rem; }
.login-submit:disabled { opacity:.65; cursor:wait; }
.prototype-note.error { background:#fff1ed; color:#9b4d37; }
@media (max-width:760px) {
  .home-features { grid-template-columns:1fr; }
  .home-feature { min-height:190px; }
  .chat-workspace { grid-template-columns:1fr; }
  .chat-sessions { position:static; }
  .chat-session-list { grid-template-columns:repeat(2,minmax(0,1fr)); max-height:180px; }
  .session-heading { flex-direction:row; align-items:baseline; justify-content:space-between; }
}