:root{--ink:#172a40;--muted:#64758b;--blue:#2563eb;--line:#e3eaf2;--paper:#fff;--bg:#f4f7fb}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:94px}
body{margin:0;color:var(--ink);background:var(--bg);font:15px/1.8 "Segoe UI","Microsoft YaHei",system-ui,sans-serif}
a{color:var(--blue);text-decoration:none}
a:hover{text-decoration:underline}
button,input{font:inherit}
button{cursor:pointer}
:focus-visible{outline:3px solid #f59e0b;outline-offset:4px}
[hidden]{display:none!important}
.skip-link{position:fixed;top:-100px;left:16px;z-index:100;background:white;padding:12px}
.skip-link:focus{top:12px}
.topbar{height:80px;position:sticky;top:0;z-index:20;display:flex;align-items:center;justify-content:space-between;padding:0 max(24px,calc((100vw - 1380px)/2));background:rgba(255,255,255,.97);border-bottom:1px solid var(--line);gap:20px}
.brand{display:flex;align-items:center;gap:12px;color:var(--ink);font-weight:750;font-size:17px;line-height:1.4}
.brand:hover{text-decoration:none}
.brand img{object-fit:contain}
.brand small{display:block;font-size:11px;font-weight:500;letter-spacing:3px;color:var(--muted);margin-top:3px}
.topbar nav{display:flex;align-items:center;gap:26px;font-size:14px}
.topbar nav a{color:#425670}
.topbar .contact{color:var(--blue);background:#eff5ff;padding:7px 14px;border-radius:8px}
.layout{display:grid;grid-template-columns:255px minmax(0,1fr);max-width:1380px;margin:auto;gap:38px;padding:30px 24px}
.sidebar{position:sticky;top:106px;align-self:start;max-height:calc(100vh - 130px);overflow:auto;padding-right:10px;scrollbar-width:thin}
.directory>summary{font-weight:700;font-size:14px;cursor:pointer;list-style:none;padding-bottom:14px}
.directory>summary span{display:none}
.search-label{font-size:12px;color:var(--muted);display:block;margin-bottom:5px}
.search-box{display:flex;align-items:center;background:white;border:1px solid #d7e1ee;border-radius:9px;overflow:hidden}
.search-box input{min-width:0;width:100%;border:0;background:none;padding:10px;font-size:13px;color:var(--ink)}
.search-box button{border:0;background:none;color:#77869a;width:32px;font-size:20px}
.search-status{font-size:12px;color:var(--muted);margin:6px 0 12px;min-height:20px}
.nav-group{margin-bottom:21px}
.nav-group>p{margin:0 0 7px;font-size:11px;font-weight:750;letter-spacing:1px;color:#8390a1}
.nav-group a{display:block;font-size:13px;color:#54667c;padding:6px 9px;border-radius:7px;line-height:1.6;margin:2px 0}
.nav-group a:hover{background:#eaf0f8;text-decoration:none}
.nav-group a.active{background:#e5eeff;color:#1f55c7;font-weight:700}
.sidebar-help{background:#eaf0f7;border-radius:12px;padding:16px;font-size:12px}
.sidebar-help p{margin:7px 0;color:var(--muted)}
main{min-width:0}
.hero{background:linear-gradient(120deg,#102b4d,#174778);border-radius:24px;padding:42px 38px;display:grid;grid-template-columns:1.3fr 1fr;gap:12px;color:white;position:relative;overflow:hidden}
.hero:after{content:"";position:absolute;width:420px;height:420px;right:-240px;top:-150px;border:1px solid #ffffff1a;border-radius:50%;pointer-events:none}
.hero-label{font-size:12px;letter-spacing:1px;color:#b9d5fb}
.hero h1{font-size:clamp(27px,3vw,39px);line-height:1.45;margin:17px 0;font-weight:750;letter-spacing:-1px}
.hero p{color:#c6d8ef;font-size:14px;margin:0 0 24px}
.hero-actions{display:flex;gap:10px;flex-wrap:wrap}
.button{display:inline-flex;align-items:center;justify-content:center;border-radius:9px;padding:10px 17px;font-size:13px;font-weight:650;line-height:1.6;text-align:center}
.button:hover{text-decoration:none;filter:brightness(.97)}
.primary{background:var(--blue);color:white}
.ghost{border:1px solid #7090b3;color:white;background:#ffffff08}
.light{background:white;border:1px solid #d7e2f0;color:#234b79}
.hero-foot{display:block;font-size:11px;color:#9eb8d9;margin-top:18px}
.hero-art{display:flex;flex-direction:column;align-items:center;justify-content:center;z-index:1}
.hero-art img{width:min(100%,230px);height:230px;object-fit:contain;filter:drop-shadow(0 14px 25px #06183088)}
.art-tag{font-size:11px;color:#d8e9ff;background:#ffffff0f;border:1px solid #ffffff1a;border-radius:20px;padding:6px 13px;white-space:nowrap;margin-top:8px}
.art-tag i{display:inline-block;width:6px;height:6px;background:#69deb6;border-radius:50%;margin-right:7px}
.quick-links{display:grid;grid-template-columns:repeat(3,1fr);gap:13px;margin:20px 0}
.quick-links a{display:flex;flex-direction:column;background:white;border:1px solid var(--line);border-radius:13px;padding:19px;color:var(--ink)}
.quick-links a:hover{border-color:#9ebdf5;text-decoration:none;box-shadow:0 5px 16px #163e7510}
.quick-links span{font-size:11px;color:var(--blue);font-weight:800}
.quick-links strong{font-size:15px;margin:6px 0}
.quick-links small{color:var(--muted);font-size:11px}
.download-bar{display:flex;align-items:center;justify-content:space-between;gap:16px;background:#eaf1fc;padding:18px 22px;border-radius:13px}
.download-bar p{font-size:12px;color:var(--muted);margin:3px 0}
.guide-note{font-size:12px;color:var(--muted);margin:22px 0}
.lesson{background:white;border:1px solid var(--line);border-radius:18px;padding:32px;margin:22px 0;scroll-margin-top:96px}
.eyebrow{font-size:11px;font-weight:750;letter-spacing:1px;color:var(--blue)}
.lesson-head h2{font-size:24px;line-height:1.5;letter-spacing:-.4px;margin:8px 0 8px}
.lesson-head>p{font-size:14px;color:var(--muted);margin:0 0 24px}
figure{margin:0 0 27px;border:1px solid var(--line);border-radius:12px;overflow:hidden;background:#f7faff}
figure img{width:100%;height:auto;display:block}
figcaption{padding:9px 14px;font-size:11px;color:#71839b;border-top:1px solid var(--line);background:white}
.steps{list-style:none;padding:0;margin:24px 0}
.steps li{display:grid;grid-template-columns:30px minmax(0,1fr);gap:14px;margin:0;padding:0 0 22px;position:relative}
.steps li:not(:last-child):before{content:"";position:absolute;left:14px;top:31px;bottom:4px;border-left:1px solid #dfe7f5}
.step-number{background:#eaf1ff;color:#205bd7;border:1px solid #d8e4fc;width:29px;height:29px;display:flex;align-items:center;justify-content:center;border-radius:50%;font-weight:700;font-size:12px;z-index:1}
.steps h3{font-size:15px;margin:0 0 4px;line-height:1.85}
.steps p{font-size:14px;color:#52647b;margin:0;line-height:1.95}
.table-wrap{overflow-x:auto;margin:24px 0;border:1px solid var(--line);border-radius:10px}
table{border-collapse:collapse;width:100%;font-size:13px;min-width:430px}
th,td{text-align:left;padding:13px 15px;vertical-align:top;border-bottom:1px solid var(--line)}
th{background:#f2f6fc;color:#445977;font-size:12px;font-weight:700}
td{color:#52647b}
tbody tr:last-child td{border-bottom:0}
tbody tr td:first-child{color:#263e5c;font-weight:600}
.callout{padding:17px 20px;border-radius:10px;margin:19px 0;font-size:13px}
.callout p{margin:6px 0 0;line-height:1.9}
.tip{background:#edf8f5;color:#285d51;border-left:3px solid #3db794}
.note{background:#fff8eb;color:#785b29;border-left:3px solid #d9a648}
.back-top{font-size:12px;color:#7186a3;display:block;text-align:right;margin-top:22px}
.app-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:24px 0}
.app-card{border:1px solid var(--line);border-radius:13px;padding:22px}
.app-icon{width:40px;height:40px;display:flex;align-items:center;justify-content:center;border-radius:11px;font-weight:800;font-size:20px}
.google{background:#edf5ff;color:#4285f4}
.microsoft{background:#e8f2ff;color:#0078d4}
.app-card h3{font-size:16px;margin:13px 0 7px}
.app-card p{font-size:13px;color:var(--muted)}
.app-card a{display:block;font-size:12px;margin:9px 0}
.faq-list details{border-bottom:1px solid var(--line)}
.faq-list summary{cursor:pointer;padding:17px 4px;font-size:14px;font-weight:650}
.faq-list p{font-size:14px;color:#52647b;margin:0 4px 20px;line-height:1.95}
.support-card{display:flex;justify-content:space-between;align-items:center;gap:18px;background:#f0f5fd;padding:22px;border-radius:12px;margin-top:26px}
.support-card h3{font-size:15px;margin:6px 0}
.support-card p{font-size:12px;color:var(--muted);margin:0}
.support-card .button{flex-shrink:0}
footer{padding:30px 0;text-align:center;font-size:12px;color:#7a8ba2}
footer strong{color:#4c6280}
footer p{margin:5px 0 12px}
.reading-progress{height:3px;position:fixed;top:0;left:0;right:0;z-index:40}
.reading-progress i{display:block;height:100%;width:0;background:#62d3b0}
#no-results{padding:30px;background:white;border-radius:14px;border:1px solid var(--line)}
#no-results h2{font-size:20px}
#no-results p{color:var(--muted)}
@media(max-width:1080px){.layout{grid-template-columns:220px minmax(0,1fr);gap:22px}.hero{padding:30px 25px}.hero-art img{height:190px}.lesson{padding:26px}.hero-actions .button{font-size:12px;padding:9px 12px}}
@media(max-width:800px){html{scroll-padding-top:88px}.topbar{height:72px;padding:0 18px}.topbar nav{gap:14px}.topbar nav a:nth-child(1),.topbar nav a:nth-child(3){display:none}.brand{font-size:15px}.brand img{width:36px;height:36px}.layout{display:block;padding:18px 16px}.sidebar{position:static;max-height:none;padding:0;margin-bottom:18px;background:white;border:1px solid var(--line);border-radius:12px}.directory>summary{padding:15px 18px;display:flex;justify-content:space-between}.directory>summary span{display:inline;font-size:11px;font-weight:400;color:var(--muted)}.directory-body{padding:0 18px 18px}.hero{padding:28px 24px}.hero h1{font-size:29px}.hero-art img{height:170px}.art-tag{font-size:10px}.lesson{padding:24px}.lesson-head h2{font-size:22px}.sidebar-help{margin-top:16px}}
@media(max-width:540px){.topbar nav{gap:8px}.topbar nav a:nth-child(2){display:none}.hero{display:block;padding:27px 23px}.hero-copy{position:relative;z-index:2}.hero-art{position:absolute;right:-26px;top:-12px;opacity:.17;pointer-events:none}.hero-art img{height:230px;width:230px}.art-tag{display:none}.hero h1{font-size:28px}.hero p{font-size:13px}.hero-actions{gap:8px}.quick-links{gap:7px}.quick-links a{padding:12px 10px}.quick-links strong{font-size:12px}.quick-links small{font-size:10px}.download-bar{align-items:flex-start;flex-direction:column;padding:17px}.lesson{padding:22px 18px;border-radius:14px}.lesson-head h2{font-size:21px}.app-grid{grid-template-columns:1fr}.support-card{display:block}.support-card .button{margin-top:15px}.steps{margin-top:20px}.steps li{gap:11px}.steps p{font-size:13px}.table-wrap{margin-left:-3px;margin-right:-3px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
@media print{.topbar,.sidebar,.hero-actions,.quick-links,.download-bar,.reading-progress,.back-top,.support-card .button{display:none!important}.layout{display:block;padding:0}body{background:white}.lesson{break-inside:avoid;border:0;padding:15px 0}.hero{color:black;background:white;padding:0}.hero p,.hero-label,.hero-foot{color:#444}.hero-art{display:none}.faq-list details p{display:block}}