:root{--ink:#1b2530;--ink2:#2c3a48;--mute:#5a6470;--line:#dde2e7;--soft:#f3f5f7;--bg:#fff;--ok:#0f7b5f;--okbg:#e7f4ef;--okline:#9fd3c2;--bad:#b42318;--badbg:#fdeceb;--badline:#f1b7b1;--flag:#9a5a00;--flagbg:#fff3dd;--font:"IBM Plex Sans",system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 var(--font)}
a{color:var(--ink);text-decoration-color:#9aa6b2;text-underline-offset:3px}
a:hover{text-decoration-color:var(--ink)}
.w{max-width:1080px;margin:0 auto;padding:0 20px}
.top{border-bottom:1px solid var(--line);background:#fff}
.top .w{display:flex;align-items:center;gap:28px;min-height:58px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;text-decoration:none;font-size:17px;white-space:nowrap}
.brand img{width:28px;height:28px;border-radius:6px}
.top nav{display:flex;gap:22px;font-size:15px;overflow-x:auto;scrollbar-width:none}
.top nav::-webkit-scrollbar{display:none}
.top nav a{text-decoration:none;color:var(--mute);white-space:nowrap;padding:4px 0;border-bottom:2px solid transparent}
.top nav a:hover{color:var(--ink)}
.top nav a[aria-current]{color:var(--ink);border-bottom-color:var(--ink)}
main{padding-top:26px;padding-bottom:64px}
h1{font-size:36px;line-height:1.18;margin:6px 0 12px;letter-spacing:-.015em;font-weight:700}
h2{font-size:24px;line-height:1.3;margin:48px 0 12px;font-weight:600}
h3{font-size:18px;margin:26px 0 8px;font-weight:600}
h1,h2,h3{text-wrap:balance}
p,li{text-wrap:pretty}
p{margin:0 0 14px}
.lede{font-size:18px;color:var(--mute);max-width:720px}
.crumbs{font-size:14px;color:var(--mute);margin:0 0 4px}
.crumbs a{color:var(--mute)}
.hero{margin-bottom:18px}
.hero .lede{margin-bottom:0}
.prose{max-width:70ch}
.prose li{margin-bottom:8px}
.fine{font-size:13.5px;color:var(--mute)}
.new{display:inline-block;margin-left:8px;font-size:12px;font-weight:600;line-height:1.5;padding:0 6px;border-radius:4px;background:var(--flagbg);color:var(--flag);vertical-align:1px;white-space:nowrap}
/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;border:1px solid var(--ink);background:var(--ink);color:#fff;border-radius:6px;padding:10px 18px;font:inherit;font-weight:600;cursor:pointer;text-decoration:none;transition:transform .08s ease,background .15s,box-shadow .15s;line-height:1.3}
.btn:hover{background:var(--ink2)}
.btn:active{transform:scale(.97)}
.btn:focus-visible,.opt:focus-visible,.tab:focus-visible,.chip:focus-visible,a:focus-visible,.grid button:focus-visible{outline:2px solid var(--ink);outline-offset:2px}
.btn[disabled]{opacity:.45;cursor:default;transform:none}
.btn.ghost{background:#fff;color:var(--ink);border-color:#b9c2cb}
.btn.ghost:hover{background:var(--soft);border-color:var(--ink)}
.btn.small{padding:6px 12px;font-size:14px}
.btn.buy{background:var(--ok);border-color:var(--ok);padding:12px 22px;font-size:17px}
.btn.buy:hover{background:#0b664e}
.cta{display:flex;gap:12px;flex-wrap:wrap;margin:18px 0}
/* app shell */
.app{border:1px solid var(--line);border-radius:10px;margin:18px 0 8px;overflow:hidden;background:#fff;box-shadow:0 1px 2px rgba(27,37,48,.05)}
.modes{display:flex;background:var(--soft);border-bottom:1px solid var(--line);overflow-x:auto;scrollbar-width:none;flex-wrap:wrap}
.modes::-webkit-scrollbar{display:none}
.tab{flex:1 1 0;min-width:150px;text-align:left;border:0;border-right:1px solid var(--line);background:transparent;padding:11px 16px 10px;font:inherit;color:var(--mute);cursor:pointer;display:flex;flex-direction:column;gap:1px;border-bottom:2px solid transparent;transition:background .15s,color .15s}
.tab:last-of-type{border-right:0}
.tab b{font-size:15px;color:var(--ink);font-weight:600;display:flex;align-items:center;gap:8px}
.tab span{font-size:13px}
.tab:hover{background:#eaeef2}
.tab.on{background:#fff;border-bottom-color:var(--ink);color:var(--ink)}
.lock{font-size:11px;font-weight:600;border:1px solid #c9d0d7;border-radius:4px;padding:0 5px;color:var(--mute);background:#fff}
.banner{flex-basis:100%;margin:0;padding:10px 16px;background:var(--okbg);border-top:1px solid var(--okline);font-size:15px}
.chips{display:flex;flex-wrap:wrap;gap:6px;align-items:center;padding:12px 20px 0}
.chip{border:1px solid var(--line);background:#fff;border-radius:6px;padding:4px 10px;font:inherit;font-size:13.5px;color:var(--mute);cursor:pointer;transition:border-color .12s,color .12s}
.chip:hover{border-color:#9aa6b2;color:var(--ink)}
.chip.on{border-color:var(--ink);color:var(--ink);font-weight:600}
.chips-note{font-size:13px;color:var(--mute);margin-left:auto}
.bar{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap;padding:12px 20px 10px}
.bar .n{font-weight:700}
.timer{font-variant-numeric:tabular-nums;font-weight:700}
.timer.low{color:var(--bad)}
.prog{height:3px;background:var(--soft);margin:0 20px}
.prog i{display:block;height:100%;background:var(--ink);transition:width .25s ease}
.q{padding:18px 20px 20px;display:grid;grid-template-columns:minmax(0,720px) minmax(0,1fr);column-gap:28px;align-content:start}
.q>*{grid-column:1}
.q>.skill{grid-column:2;grid-row:1/span 8;align-self:start;border-left:1px solid var(--line);padding:2px 0 0 18px;font-size:13.5px;color:var(--mute)}
.skill p{margin:0 0 6px}
.skill-h{font-weight:600;color:var(--ink)}
.skill-h .new{margin-left:6px}
.skill-t{line-height:1.5}
.skill a{color:var(--mute)}
.q.enter{animation:qin .18s ease-out}
@keyframes qin{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.q .meta{font-size:13.5px;color:var(--mute);margin-bottom:8px}
.multi-tag{color:var(--ink)}
.q .stem{font-size:17.5px;line-height:1.65;margin-bottom:18px;max-width:780px}
.opts{display:flex;flex-direction:column;gap:8px;max-width:780px}
.opt{display:flex;gap:12px;align-items:flex-start;text-align:left;width:100%;border:1px solid var(--line);background:#fff;border-radius:8px;padding:11px 14px;font:inherit;color:inherit;cursor:pointer;transition:border-color .12s,background .12s,transform .08s,opacity .15s;line-height:1.55}
.opt:hover{border-color:#9aa6b2}
.opt:active{transform:scale(.995)}
.opt .k{flex:none;width:26px;height:26px;border:1px solid #c3cbd3;border-radius:50%;display:grid;place-items:center;font-size:13px;font-weight:700;color:var(--mute);margin-top:-1px;transition:background .12s,border-color .12s,color .12s}
.opt.multi .k{border-radius:5px}
.opt[aria-pressed=true]{border-color:var(--ink);background:#f6f8fa}
.opt[aria-pressed=true] .k{background:var(--ink);border-color:var(--ink);color:#fff}
.opt.right{border-color:var(--okline);background:var(--okbg)}
.opt.right .k{background:var(--ok);border-color:var(--ok);color:#fff}
.opt.wrong{border-color:var(--badline);background:var(--badbg)}
.opt.wrong .k{background:var(--bad);border-color:var(--bad);color:#fff}
.opt.dim{opacity:.8}
.opt.locked{cursor:default;transform:none}
.why{display:block;font-size:14.5px;color:var(--mute);margin-top:5px;animation:fade .2s ease-out}
.expl{max-width:780px;margin-top:16px;padding:14px 16px;border-left:3px solid var(--ok);background:var(--okbg);border-radius:0 8px 8px 0;font-size:15.5px;animation:drop .2s ease-out}
.expl.bad{border-color:var(--bad);background:#fbf3f2}
.expl b{display:block;margin-bottom:4px}
.expl p{margin:0 0 8px}
.expl p:last-child{margin:0}
@keyframes drop{from{opacity:0;transform:translateY(-4px)}to{opacity:1;transform:none}}
@keyframes fade{from{opacity:0}to{opacity:1}}
.refs{font-size:14px;color:var(--mute)}
.refs a{color:var(--ink2)}
.nav{display:flex;gap:10px;flex-wrap:wrap;margin-top:20px;align-items:center;max-width:780px}
.nav .sp{flex:1}
.keys{font-size:13px;color:var(--mute);margin:14px 0 0}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(38px,1fr));gap:6px;max-width:780px;margin-top:18px}
.grid button{height:34px;border:1px solid var(--line);background:#fff;border-radius:5px;font:inherit;font-size:13px;cursor:pointer}
.grid button.done{background:#e9edf1}
.grid button.flag{border-color:var(--flag);background:var(--flagbg)}
.grid button.cur{outline:2px solid var(--ink);outline-offset:-1px}
.app-b{padding:20px}
.app-b+.app-b{border-top:1px solid var(--line)}
.score{display:flex;gap:16px;align-items:baseline;flex-wrap:wrap;margin-bottom:8px}
.score b{font-size:48px;line-height:1;font-variant-numeric:tabular-nums}
.dom{display:grid;grid-template-columns:minmax(0,1fr) 160px 52px;gap:14px;align-items:center;padding:9px 0;border-top:1px solid var(--line);font-size:15px;max-width:780px}
.dom b{text-align:right;font-variant-numeric:tabular-nums}
.meter{height:8px;background:#e7ebef;border-radius:4px;overflow:hidden}
.meter i{display:block;height:100%;background:var(--ink);transition:width .4s ease}
.meter i.lo{background:var(--bad)}
.meter i.hi{background:var(--ok)}
.worst{margin-top:12px}
.overall h3{margin-top:0;font-size:16px}
.wall{border:1px solid var(--okline);border-radius:10px;padding:20px 22px;margin-top:22px;background:#f7fbf9;max-width:780px;animation:drop .2s ease-out}
.wall h3{margin:0 0 6px;font-size:21px}
.wall .lead{margin-bottom:6px}
.wall ul{margin:8px 0 14px;padding-left:20px}
.wall li{margin-bottom:5px}
.buy-row{display:flex;align-items:center;gap:14px;flex-wrap:wrap;margin:12px 0 4px}
.preview{border-top:1px solid var(--okline);margin-top:14px;padding-top:12px}
.pv-stem{font-size:15px;margin:0 0 6px}
.pv-opts{font-size:13.5px;color:var(--mute);margin:0}
.topics{display:flex;flex-wrap:wrap;gap:6px;margin:8px 0 16px}
.topics span{font-size:13px;border:1px solid var(--line);border-radius:4px;padding:1px 7px;background:#fff;color:var(--mute)}
details.signin{margin-top:14px;font-size:14px}
details.signin summary{cursor:pointer;color:var(--mute)}
details.signin .row{display:flex;gap:8px;margin-top:8px;flex-wrap:wrap}
details.signin input{font:inherit;padding:6px 8px;border:1px solid #b9c2cb;border-radius:6px;min-width:220px}
.tag{font-size:12px;font-weight:600;border:1px solid var(--line);border-radius:4px;padding:1px 6px;color:var(--mute);white-space:nowrap}
.tag.ok{color:var(--ok);border-color:var(--okline);background:var(--okbg)}
.tag.bad{color:var(--bad);border-color:var(--badline);background:var(--badbg)}
.rv{margin-bottom:10px;max-width:780px}
.rv summary{cursor:pointer}
.rv-b{padding:10px 0}
/* content */
.facts{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));border:1px solid var(--line);border-radius:10px;margin:16px 0}
.facts div{padding:14px 18px;border-left:1px solid var(--line)}
.facts div:first-child{border-left:0}
.facts b{display:block;font-size:26px;line-height:1.2;font-variant-numeric:tabular-nums}
.facts span{font-size:14px;color:var(--mute)}
table{border-collapse:collapse;width:100%;margin:12px 0 20px;font-size:15px}
th,td{border-bottom:1px solid var(--line);padding:9px 12px;text-align:left;vertical-align:top}
thead th{background:var(--soft);font-weight:600;border-bottom:1px solid #cdd4db;font-size:14px}
td.num,th.num{text-align:right;font-variant-numeric:tabular-nums;white-space:nowrap}
table.skills td:first-child{width:64px;text-align:left;color:var(--mute)}
table.skills td:last-child{width:110px}
table.svc td{padding:6px 12px}
table.svc td:first-child{width:46%}
table.svc td:last-child{width:120px}
table.cmp td:first-child{font-weight:600}
td .sub{display:block;font-size:13.5px;color:var(--mute)}
td ul{margin:0;padding-left:18px}
.tw{overflow-x:auto;max-width:900px}
.toc{columns:2;column-gap:32px;padding-left:20px;max-width:900px}
.toc li{break-inside:avoid;margin-bottom:6px}
.decide li{margin-bottom:10px}
.fig{margin:24px 0 8px;max-width:760px}
.fig img{display:block;max-width:100%;height:auto;border:1px solid var(--line);border-radius:8px;background:#fff;padding:12px}
.fig figcaption{font-size:14px;color:var(--mute);margin-top:8px}
th{white-space:nowrap}
.moved{max-width:760px}
.qlist li{margin-bottom:8px}
.pn{margin-top:36px;font-weight:600}
.jump{display:flex;gap:8px 18px;flex-wrap:wrap;font-size:15px}
.sq{border:1px solid var(--line);border-radius:10px;padding:18px 20px;margin:16px 0;max-width:820px;scroll-margin-top:12px}
.sq:target{border-color:var(--ink)}
.qmeta{font-size:13.5px;color:var(--mute);margin-bottom:8px}
.sq .stem{margin-bottom:12px}
.olist{list-style:none;margin:0 0 10px;padding:0}
.olist li{display:flex;gap:10px;margin-bottom:6px}
.olist .k{flex:none;font-weight:700;width:18px}
.sq details{margin-top:8px}
.sq summary{cursor:pointer;font-weight:600}
.sq .ans{margin-top:10px;font-size:15.5px;border-top:1px solid var(--line);padding-top:10px}
.sq .ans p{margin:0 0 8px}
.why-h{font-weight:600;margin-top:10px!important}
.sq .ans ul{margin:0 0 8px;padding-left:20px}
footer{border-top:1px solid var(--line);background:var(--soft);padding:26px 0;font-size:14px;color:var(--mute)}
footer p{margin:0 0 10px;max-width:780px}
footer a{color:var(--mute)}
footer .fl{display:flex;flex-wrap:wrap;gap:6px 18px}
@media (max-width:760px){
h1{font-size:28px}
h2{font-size:21px;margin-top:40px}
.lede{font-size:16.5px}
.top .w{gap:6px 16px;flex-wrap:wrap;padding-top:10px;padding-bottom:4px}
.top nav{gap:16px;width:100%}
.facts{grid-template-columns:repeat(2,minmax(0,1fr))}
.facts div:nth-child(3){border-left:0}
.facts div:nth-child(n+3){border-top:1px solid var(--line)}
.modes{flex-wrap:nowrap}
.tab{min-width:136px;flex:0 0 auto;padding:9px 12px 8px}
.chips{padding:10px 14px 0;flex-wrap:nowrap;overflow-x:auto;scrollbar-width:none}
.chips::-webkit-scrollbar{display:none}
.chip{white-space:nowrap}
.chips-note{display:none}
.bar{padding:10px 14px 8px}
.prog{margin:0 14px}
.q,.app-b{padding:16px 14px}
.q{display:block}
.q>.skill{display:none}
.tab span{display:none}
.tab{min-width:0;padding:10px 14px 9px}
.tab b{font-size:14.5px}
.hero .lede{font-size:15.5px}
.chips{padding-top:8px}
.bar .fine{display:none}
.bar{flex-wrap:nowrap}
.q .stem{font-size:16.5px}
.opt{padding:10px 12px}
.keys{display:none}
.dom{grid-template-columns:minmax(0,1fr) 52px}
.dom .meter{grid-column:1/-1;order:3}
.toc{columns:1}
.sq{padding:16px}
}
.overall{margin-top:26px}
.more{max-width:820px;font-size:15px;color:var(--mute);margin:4px 0 0}
@media (prefers-reduced-motion:reduce){*,*::before,*::after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}
.olist li>span:last-child,.opt .t,.stem,.expl,.why,.sq .ans{overflow-wrap:anywhere}
.kv th{width:200px;background:transparent;font-weight:600;border-bottom:1px solid var(--line)}
.q .meta .new{margin-left:8px}
@media (max-width:760px){.wall{padding:16px;margin-top:12px}.wall h3{font-size:19px}}
.fig.shot{max-width:900px}.fig.shot img{padding:0}