:root{--brand-core:#6B238E;--brand-mist:#F4F0F8;--ink:#17131C;--paper:#FCFBFD;--white:#FFF;--line:#D8D3DE;--muted:#655E6B;--focus:#7A3FA0}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--paper);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Helvetica Neue",sans-serif;font-size:17px;line-height:1.72}a{color:var(--brand-core);text-decoration-thickness:1px;text-underline-offset:3px}.skip-link{position:absolute;left:-10000px;top:8px;background:var(--ink);color:#fff;padding:8px 12px;z-index:10}.skip-link:focus{left:8px}.site-header{position:sticky;top:0;z-index:5;min-height:68px;display:flex;align-items:center;gap:28px;padding:12px max(32px,calc((100% - 1200px)/2));background:rgba(252,251,253,.98);border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:16px;color:var(--ink);font-size:14px;font-weight:700;text-decoration:none;white-space:nowrap}.brand img{width:122px;height:auto;max-height:30px}.brand span{border-left:1px solid var(--line);padding-left:16px}.site-header nav{display:flex;align-items:center;gap:24px;margin-left:auto}.site-header nav a{color:var(--muted);font-size:14px;text-decoration:none}.site-header nav a[aria-current=location]{color:var(--ink);font-weight:700;border-bottom:2px solid var(--brand-core)}.download-link{padding:8px 18px;border-radius:10px;background:var(--brand-core);color:#fff;font-size:14px;font-weight:700;text-decoration:none;white-space:nowrap}main{max-width:1200px;margin:0 auto;padding:0 32px 80px}section{scroll-margin-top:88px;padding:96px 0;border-bottom:1px solid var(--line)}.opener{min-height:660px;display:grid;grid-template-columns:7fr 5fr;gap:48px;align-items:center;padding-top:64px}.opener-copy{max-width:720px}.eyebrow{margin:0 0 14px;color:var(--brand-core);font-size:14px;font-weight:800;letter-spacing:.05em}.opener h1{max-width:650px;margin:0 0 20px;font-size:56px;line-height:1.08;letter-spacing:0}.lede{max-width:680px;margin:0 0 34px;font-size:18px}.bridge-hero{display:flex;align-items:center;gap:20px;flex-wrap:wrap;margin:28px 0 10px}.bridge-hero>span{font-size:14px;color:var(--muted)}.keycap{display:inline-flex;align-items:center;justify-content:center;min-height:64px;padding:0 22px;border:1px solid #D8D3DE;border-radius:8px;background:#fff;box-shadow:0 2px 0 #C8C2CC;font:700 19px/1.2 ui-monospace,SFMono-Regular,Menlo,monospace;white-space:nowrap}.keycap-windows{width:96px}.keycap-command{width:184px;color:var(--brand-core);border-color:var(--brand-core);background:var(--brand-mist)}.keycap-command b{font-size:30px;margin-right:9px}.qualification{max-width:600px;margin:0;color:var(--muted);font-size:14px}.arc{display:block;width:200px;height:auto;margin:23px 0 18px}.text-link{font-size:15px;font-weight:700}.app-proof{margin:0}.app-proof img{display:block;width:100%;height:auto;border:1px solid var(--line);border-radius:12px;box-shadow:0 12px 36px rgba(29,23,34,.08)}figcaption{margin-top:14px;color:var(--muted);font-size:14px}.app-proof-small{max-width:480px}.section-heading{max-width:760px}.section-intro{max-width:760px;margin-top:-8px;color:var(--muted)}h2{margin:0 0 28px;font-size:36px;line-height:1.22;letter-spacing:0}h3{margin:0 0 8px;font-size:22px;line-height:1.35}kbd{display:inline-block;border:1px solid #BEB5C2;border-radius:4px;background:#fff;box-shadow:0 2px 0 #BEB5C2;padding:1px 7px;font:700 .87em/1.45 ui-monospace,SFMono-Regular,Menlo,monospace;white-space:nowrap}.symbol-list{display:grid;grid-template-columns:repeat(5,1fr);list-style:none;padding:0;margin:0;border-top:1px solid var(--line)}.symbol-list li{display:flex;gap:14px;align-items:center;min-height:112px;padding:16px;border-bottom:1px solid var(--line)}.keycap-small{width:52px;height:44px;min-height:44px;padding:0;font-size:22px}.symbol-list strong,.symbol-list span{display:block}.symbol-list span{margin-top:4px;color:var(--muted);font-size:14px;line-height:1.4}.bridge-table{border-top:2px solid var(--ink)}.bridge-row{display:grid;grid-template-columns:240px 300px 1fr;gap:24px;align-items:center;min-height:72px;padding:14px 0;border-bottom:1px solid var(--line)}.bridge-head{min-height:48px;color:var(--muted);font-size:14px;font-weight:700}.bridge-row small{color:var(--muted);font-size:14px}.input-layout{display:grid;grid-template-columns:7fr 5fr;gap:48px}.input-list article{padding:24px 0;border-top:1px solid var(--line)}.input-list article:last-child{border-bottom:1px solid var(--line)}.input-list p{max-width:680px;margin:0}.tag{display:inline-block;margin-bottom:10px;padding:2px 9px;border-radius:999px;background:var(--brand-mist);color:var(--brand-core);font-size:13px;font-weight:700}.mist-panel{align-self:start;padding:28px;background:var(--brand-mist)}.mist-panel ol{margin:12px 0;padding-left:22px}.mist-panel p{margin:0;color:var(--muted);font-size:14px}.shortcut-groups{display:grid;grid-template-columns:1fr 1fr;gap:56px 48px}.shortcut-groups article:nth-child(3),.shortcut-groups article:nth-child(4){grid-column:span 1}.shortcut-groups h3{padding-bottom:12px;border-bottom:2px solid var(--ink)}dl{margin:0}dl>div{display:grid;grid-template-columns:170px 1fr;gap:20px;align-items:center;min-height:64px;border-bottom:1px solid var(--line)}dt{margin:0}dd{margin:0}dd small{display:block;color:var(--muted);font-size:13px}.aixlg-layout{display:grid;grid-template-columns:7fr 5fr;gap:48px;align-items:start}.representative{display:grid;grid-template-columns:130px 1fr;gap:20px;padding:17px 0;border-top:1px solid var(--line)}.representative:last-child{border-bottom:1px solid var(--line)}.representative h3{font-size:19px;margin:0 0 3px}.representative p{margin:0;color:var(--muted);font-size:14px}.representative>.tag{margin:0}.aixlg-layout+.details{}.aixlg-layout~details{margin-top:32px;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}summary{min-height:52px;padding:12px 0;cursor:pointer;font-weight:700}details p{max-width:760px;margin:0 0 18px}.practice{border:0;background:var(--brand-mist);padding:56px 48px;margin-top:0}.practice-list{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;list-style:none;padding:0;margin:0;counter-reset:step}.practice-list li{counter-increment:step;min-height:150px;padding:20px;border-top:3px solid var(--line);background:#fff}.practice-list li:before{content:counter(step);display:block;margin-bottom:14px;color:var(--brand-core);font-weight:800;font-size:24px}.practice-list label{display:block;cursor:pointer}.practice-list input{width:20px;height:20px;margin:0 8px 0 0;vertical-align:middle;accent-color:var(--brand-core)}.practice-complete{margin:26px 0 0;font-weight:700;color:var(--brand-core)}.references p{max-width:760px}.references h2{font-size:28px}footer{max-width:1200px;margin:0 auto;padding:30px 32px;color:var(--muted);font-size:14px}footer p{margin:4px 0}:focus-visible{outline:3px solid rgba(122,63,160,.35);outline-offset:3px}@media(max-width:900px){.site-header{gap:16px;padding:12px 20px}.site-header nav{gap:12px}.download-link{display:none}.opener{grid-template-columns:1fr;gap:36px}.app-proof{max-width:620px}.symbol-list{grid-template-columns:repeat(2,1fr)}.symbol-list li:last-child{grid-column:span 2}.input-layout,.aixlg-layout{grid-template-columns:1fr;gap:32px}.shortcut-groups{gap:40px 24px}.practice-list{grid-template-columns:repeat(2,1fr)}}@media(max-width:720px){body{font-size:16px}.site-header{min-height:56px;padding:10px 16px}.brand img{width:88px}.brand{gap:10px}.brand span{padding-left:10px}.site-header nav{display:none}main{padding:0 16px 48px}section{padding:56px 0;scroll-margin-top:72px}.opener{min-height:0;padding-top:48px}.opener h1{font-size:34px;line-height:1.14}.lede{font-size:16px}.bridge-hero{display:flex;flex-direction:column;align-items:center;gap:12px}.bridge-hero>span{order:2}.keycap-windows{order:1}.keycap-command{order:3}.qualification{text-align:center}.arc{width:190px;margin:22px auto}.text-link{display:block;text-align:center}h2{font-size:28px;line-height:1.28}.symbol-list{grid-template-columns:1fr}.symbol-list li,.symbol-list li:last-child{grid-column:auto;min-height:64px;padding:10px 0}.bridge-head{display:none}.bridge-row{display:block;padding:18px 0}.bridge-row strong,.bridge-row span,.bridge-row small{display:block}.bridge-row span{margin:8px 0}.input-layout{gap:24px}.shortcut-groups{display:block}.shortcut-groups article{margin-top:40px}.shortcut-groups article:first-child{margin-top:0}.shortcut-groups dl>div{grid-template-columns:130px 1fr;gap:12px;min-height:58px}.aixlg-layout{gap:32px}.representative{grid-template-columns:116px 1fr;gap:12px}.practice{padding:36px 20px}.practice-list{display:block}.practice-list li{min-height:0;margin:12px 0;padding:16px}.references h2{font-size:24px}.app-proof-small{max-width:none}}@media(max-width:340px){main{padding-left:14px;padding-right:14px}.brand span{display:none}.keycap{padding:0 14px}.keycap-command{width:auto}.shortcut-groups dl>div{grid-template-columns:1fr;gap:6px;padding:12px 0}.representative{grid-template-columns:1fr}.representative>kbd{justify-self:start}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation-duration:.01ms!important;transition-duration:.01ms!important}}@media(forced-colors:active){.site-header{background:Canvas}.site-header img{forced-color-adjust:none}.keycap,.symbol-list li,.practice-list li,.mist-panel{border:1px solid ButtonText}.download-link{background:Highlight;color:HighlightText}.tag{border:1px solid ButtonText;background:Canvas;color:CanvasText}}
/* Mobile lesson navigation stays available without competing with download. */
@media(max-width:720px){
  .site-header{flex-wrap:wrap;row-gap:0}
  .site-header nav{display:grid;order:3;grid-template-columns:repeat(2,minmax(0,1fr));width:100%;margin:10px 0 -10px;gap:0;border-top:1px solid var(--line)}
  .site-header nav a{display:flex;align-items:center;min-height:44px;padding:6px 8px;font-size:14px;line-height:1.25}
  .site-header nav a:nth-child(odd){padding-left:0}
  .site-header nav a:nth-child(even){padding-left:16px;border-left:1px solid var(--line)}
  section{scroll-margin-top:160px}
  .symbol-list li{gap:12px}
  .symbol-list li>div{min-width:0}
  .symbol-list .keycap-fn{min-width:68px;width:max-content;flex:0 0 auto;padding-inline:6px;font-size:14px}
}
/* Local memory anchors remain decorative and never replace lesson text. */
.memory-icon{display:inline-block;width:128px;height:128px;aspect-ratio:1;object-fit:contain;vertical-align:middle;pointer-events:none;flex:0 0 auto;border:0;box-shadow:none}
h2.memory-title{display:inline-block;max-width:calc(100% - 160px);vertical-align:middle;margin-bottom:28px}
h2.memory-title + .memory-icon{margin:0 0 28px 24px}
h3.memory-subtitle{display:flex;align-items:center;justify-content:space-between;gap:14px}
h3.memory-subtitle .memory-icon{width:104px;height:104px}
@media(max-width:720px){
  h2.memory-title{max-width:calc(100% - 104px);margin-bottom:28px}
  h2.memory-title + .memory-icon{width:88px;height:88px;margin:0 0 28px 12px}
  h3.memory-subtitle .memory-icon{width:76px;height:76px}
}
.danger-note{display:block;margin-top:4px;color:#B42318;font-size:13px;font-weight:700}
.shortcut-note{margin:-4px 0 8px;color:var(--muted);font-size:13px;font-weight:700}
.symbol-list .keycap-fn{min-width:68px;width:max-content;flex:0 0 auto;padding-inline:6px;font-size:14px}
.advanced-section{border-top:1px solid var(--line);background:#fff;padding-top:48px;scroll-margin-top:72px}
.advanced-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:28px;margin-top:28px}
.advanced-grid article{border-top:2px solid var(--ink);padding-top:16px}
.advanced-grid h3{margin:0 0 14px;font-size:20px}
.advanced-definitions{margin:0}
.advanced-definitions div{display:grid;grid-template-columns:120px 1fr;gap:12px;padding:10px 0;border-top:1px solid var(--line)}
.advanced-definitions div:first-child{border-top:0}
.advanced-definitions dt{font-weight:800}
.advanced-definitions dd{margin:0;color:var(--muted)}
.advanced-list{list-style:none;margin:0;padding:0}
.advanced-list li{display:grid;grid-template-columns:max-content 1fr;gap:12px;padding:10px 0;border-top:1px solid var(--line);align-items:start}
.advanced-list li:first-child{border-top:0}
.advanced-list span{color:var(--muted)}
.advanced-example{grid-column:1 / -1;max-width:760px}
.advanced-example p{margin:10px 0}
.advanced-example strong{color:var(--ink)}
@media(max-width:900px){.advanced-grid{grid-template-columns:1fr 1fr}.advanced-example{grid-column:1 / -1}}
@media(max-width:720px){.advanced-section{padding-top:40px;scroll-margin-top:160px}.advanced-grid{display:block}.advanced-grid article{margin-top:28px}.advanced-grid article:first-child{margin-top:0}.advanced-example{max-width:none}.advanced-list li{grid-template-columns:1fr;gap:6px}.advanced-definitions div{grid-template-columns:1fr;gap:4px}}
@media(forced-colors:active){.danger-note{color:CanvasText;border:1px solid ButtonText;padding:2px 6px}.shortcut-note{color:CanvasText}}