:root{color-scheme:light;--ink:#182b35;--muted:#61717a;--line:#dce3e4;--paper:#fff;--bg:#f5f7f6;--accent:#126453;--soft:#eaf3ef}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:100px}body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.7 -apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}a{color:var(--accent);text-underline-offset:4px}a:hover{color:#083e33}a:focus-visible,button:focus-visible{outline:3px solid #bb8233;outline-offset:5px}.wrap{width:min(1120px,calc(100% - 64px));margin:auto}.skip{position:absolute;top:-100px;left:20px;background:white;padding:12px;z-index:10}.skip:focus{top:10px}.header{background:var(--paper);border-bottom:1px solid var(--line)}.header-inner{min-height:86px;display:flex;align-items:center;justify-content:space-between;gap:20px}.identity{display:flex;align-items:center;gap:14px;text-decoration:none;color:var(--ink)}.mark{background:var(--ink);color:white;width:40px;height:40px;display:grid;place-items:center;font-size:13px;font-weight:700;letter-spacing:1px;border-radius:8px}.identity strong{display:block;font-size:14px}.identity small{display:block;color:var(--muted);font-size:12px}.term,.eyebrow{font-size:11px;font-weight:700;letter-spacing:1.8px;text-transform:uppercase}.term{border:1px solid var(--line);padding:7px 12px;border-radius:5px}.hero{padding:66px 0 44px;position:relative}.eyebrow{color:var(--accent);margin:0 0 18px}h1{font-size:clamp(36px,5vw,58px);letter-spacing:-2px;line-height:1.08;font-weight:600;margin:0 0 22px;max-width:780px}.intro{color:var(--muted);font-size:18px;max-width:630px;margin:0}.meta{display:flex;gap:22px;align-items:center;margin-top:28px;font-size:13px;color:var(--muted)}.badge{background:var(--soft);color:var(--accent);border-radius:5px;padding:5px 10px;font-weight:600}.badge::before{content:"";display:inline-block;width:6px;height:6px;background:var(--accent);border-radius:50%;margin:0 7px 2px 0}.layout{display:grid;grid-template-columns:210px minmax(0,1fr);gap:42px;padding-bottom:72px}.sidebar{align-self:start;position:sticky;top:28px;border-top:1px solid var(--line);padding-top:20px}.side-label{font-size:10px;letter-spacing:1.5px;color:var(--muted);font-weight:700;margin:0 0 15px}.sidebar a{display:block;text-decoration:none;font-size:13px;color:var(--muted);padding:8px 0}.sidebar a:hover{color:var(--accent)}.sidebar a span{display:inline-block;font-size:11px;width:27px;color:var(--accent)}.side-note{border-top:1px solid var(--line);margin-top:22px;padding-top:20px;font-size:12px;color:var(--muted)}.content{background:var(--paper);border:1px solid var(--line);border-radius:12px;overflow:hidden}.section{padding:34px 40px;border-bottom:1px solid var(--line)}.section:last-child{border-bottom:0}.section-label{font-size:10px;color:var(--accent);letter-spacing:1.6px;font-weight:700;margin:0 0 8px}h2{font-size:24px;line-height:1.25;letter-spacing:-.65px;margin:0 0 18px;font-weight:600}h3{font-size:15px;margin:24px 0 10px}p{margin:0 0 16px}.section p,.section li{font-size:14px}.resources{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:22px}.resource{display:flex;align-items:center;justify-content:space-between;border:1px solid var(--line);border-radius:7px;padding:14px 16px;text-decoration:none;font-size:13px;font-weight:600}.resource:hover{background:var(--soft)}.resource span{font-size:18px}.specs{display:grid;grid-template-columns:repeat(3,1fr);margin:22px 0;border:1px solid var(--line);border-radius:7px;overflow:hidden}.specs div{padding:15px 18px;background:var(--bg);border-right:1px solid var(--line)}.specs div:last-child{border:0}.specs dt{font-size:11px;color:var(--muted)}.specs dd{margin:2px 0 0;font-size:21px;font-weight:600;letter-spacing:-.5px}.specs dd small{font-size:12px;font-weight:400}.steps{padding-left:23px;margin:12px 0}.steps li{padding-left:8px;margin:10px 0}.steps li::marker{color:var(--accent);font-weight:600}code{font:12px/1.7 ui-monospace,SFMono-Regular,Consolas,monospace;overflow-wrap:anywhere}.code{display:block;border:1px solid var(--line);background:var(--bg);border-radius:6px;padding:13px 16px;margin:12px 0 24px}.note-box{background:var(--soft);border-radius:7px;padding:20px;margin-top:24px}.note-box h3{margin-top:0}.note-box p:last-child{margin-bottom:0}figure{margin:25px 0 0;text-align:center}figure img{max-width:100%;height:auto}figcaption{font-size:11px;color:var(--muted);margin-top:8px}.gates{display:flex;gap:8px;margin:18px 0}.gates span{border:1px solid var(--line);padding:5px 16px;border-radius:5px;font:12px/1.7 ui-monospace,monospace}.footer{border-top:1px solid var(--line);padding:22px 0;color:var(--muted);font-size:11px}.footer .wrap{display:flex;justify-content:space-between;gap:20px}.footer p{margin:0}
@media(max-width:760px){.wrap{width:calc(100% - 36px)}.header-inner{min-height:74px}.identity small{font-size:10px}.term{font-size:9px;letter-spacing:1px}.hero{padding:42px 0 30px}h1{letter-spacing:-1.3px}.intro{font-size:16px}.layout{grid-template-columns:1fr;gap:20px}.sidebar{position:static;padding-top:15px}.sidebar nav{display:flex;flex-wrap:wrap;gap:8px 20px}.side-label,.side-note{display:none}.sidebar a{font-size:12px}.section{padding:26px 22px}.specs div{padding:12px}.resources{grid-template-columns:1fr}.meta{flex-wrap:wrap;gap:12px}.footer .wrap{display:block}.footer p+p{margin-top:8px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}@media print{.sidebar,.skip{display:none}.layout{display:block}.wrap{width:100%}.hero{padding:20px 0}.section{break-inside:avoid}body{background:white}.footer{margin-top:20px}}
.assignment-title{font-size:clamp(28px,4vw,43px);line-height:1.2;letter-spacing:-1.2px;max-width:940px}.original-steps p{padding-left:22px;text-indent:-16px;margin:16px 0}.wording-specs{margin:20px 0}.spec-grid{display:grid;grid-template-columns:repeat(3,1fr);border:1px solid var(--line);border-radius:7px;background:var(--bg);overflow:hidden}.spec-grid p{margin:0;padding:16px;border-right:1px solid var(--line)}.spec-grid p:last-child{border:0}.spec-grid strong{display:block;font-size:23px;margin-top:7px;letter-spacing:-.5px}@media(max-width:520px){.spec-grid{grid-template-columns:1fr}.spec-grid p{border-right:0;border-bottom:1px solid var(--line)}}
/* Common shell and editorial layout for every course page. */
:root{--ink:#202c3c;--muted:#637084;--line:#e0e5ec;--paper:#fff;--bg:#f7f8fb;--accent:#315ad9;--soft:#edf2ff}
body{font-size:15px;-webkit-font-smoothing:antialiased}.wrap{width:min(1160px,calc(100% - 64px))}.header-inner{min-height:80px}.mark{background:var(--accent);border-radius:10px}.term{background:var(--bg);border:0;border-radius:6px;color:var(--muted)}.site-nav{background:white;border-bottom:1px solid var(--line)}.site-nav nav{display:flex;gap:28px}.site-nav a{font-size:13px;font-weight:500;text-decoration:none;color:var(--muted);padding:15px 0 12px;border-bottom:3px solid transparent}.site-nav a:hover{color:var(--accent)}.site-nav a[aria-current]{color:var(--accent);border-bottom-color:var(--accent)}.hero{padding:48px 0 36px}h1{font-size:clamp(30px,4vw,44px);letter-spacing:-1.5px;line-height:1.15;max-width:820px}.eyebrow{font-size:10px;letter-spacing:1.4px;margin-bottom:14px}.intro{font-size:16px}.meta{margin-top:22px}.layout{grid-template-columns:200px minmax(0,1fr);gap:36px}.sidebar{border-top:0;padding-top:8px;top:24px}.sidebar a{display:flex;gap:6px;padding:8px 10px;font-size:12px;border-radius:6px;line-height:1.5}.sidebar a span{flex:0 0 20px}.sidebar a:hover{background:var(--soft)}.content,.setup{border-radius:12px;box-shadow:0 3px 15px #202c3c03}.section{padding:32px 36px}h2{font-size:23px}.section-label{font-size:10px}.specs{border:0;background:var(--bg);border-radius:8px}.specs div{padding:18px 20px}.specs dd{font-size:27px;margin-top:7px}.specs dt{font-size:11px}.note-box{border:1px solid #dce5ff;background:#f4f7ff;padding:24px;border-radius:9px}.note-box h3{font-size:19px;margin:0 0 12px}.equation{display:flex;justify-content:center;padding:20px 10px;margin:16px 0;background:white;border:1px solid #e0e7fb;border-radius:7px}.equation math{font-size:25px}.note-box sub{font-size:.7em}.original-steps p{padding-left:24px;text-indent:-17px;margin:17px 0}.code{background:var(--bg);padding:16px;border:0}.gates span{background:var(--bg);border:0;padding:7px 17px}.footer{background:white}
@media(max-width:760px){.wrap{width:calc(100% - 36px)}.header-inner{min-height:70px}.hero{padding:32px 0 26px}.layout{grid-template-columns:1fr;gap:20px}.sidebar{padding-top:0}.sidebar nav{gap:4px 8px}.sidebar a{padding:6px 8px}.section{padding:26px 22px}.site-nav nav{gap:24px}.specs div{padding:14px 10px}.specs dd{font-size:23px}.specs dt{font-size:10px}.note-box{padding:20px}}
@media print{.site-nav{display:none}.layout{display:block}}
.sidebar nav{max-height:calc(100vh - 100px);overflow-y:auto;scrollbar-width:thin}.site-nav a:focus-visible{outline-offset:-3px}@media(max-width:760px){.sidebar nav{max-height:150px}.sidebar a{max-width:100%}}
/* Theme tokens cover every shared surface, including navigation and equations. */
:root{--callout:#f4f7ff;--callout-line:#dce5ff;--shadow:0 8px 32px #202c3c14}
:root[data-theme="dark"]{color-scheme:dark;--ink:#e2e8f2;--muted:#a4b0c4;--line:#303c50;--paper:#192231;--bg:#111925;--accent:#9aafff;--soft:#253451;--callout:#202e48;--callout-line:#3a4d70;--shadow:0 8px 32px #0005}
.site-nav,.footer,.equation,.skip{background:var(--paper)}.note-box{background:var(--callout);border-color:var(--callout-line)}.equation{border-color:var(--callout-line)}a:hover{color:var(--accent)}.identity:hover{color:var(--ink)}.mark{background:#3c56cf;color:white}.skip{color:var(--ink)}
.header-actions{display:flex;align-items:center;gap:12px}.theme-toggle,.contents-close{display:grid;place-items:center;width:34px;height:34px;padding:0;border:1px solid var(--line);border-radius:8px;color:var(--ink);background:var(--paper);cursor:pointer;font:21px/1 system-ui}.theme-toggle:hover,.contents-close:hover{background:var(--soft)}
.sidebar a[aria-current="location"],.contents-dialog a[aria-current="location"]{background:var(--soft);color:var(--accent)}
.contents-trigger{position:fixed;right:24px;bottom:24px;z-index:40;padding:12px 17px;border:1px solid var(--line);border-radius:10px;background:var(--paper);color:var(--ink);box-shadow:var(--shadow);font:600 13px/1.3 system-ui;cursor:pointer}.contents-trigger:hover{background:var(--soft)}
.contents-dialog{position:fixed;inset:0 0 0 auto;margin:0;height:100%;max-height:100%;width:min(400px,100%);max-width:100%;padding:0;border:0;border-left:1px solid var(--line);background:var(--paper);color:var(--ink);box-shadow:var(--shadow)}.contents-dialog::backdrop{background:#080e2080}.contents-header{display:flex;justify-content:space-between;align-items:center;padding:24px;border-bottom:1px solid var(--line)}.contents-header h2{font-size:20px;margin:0}.contents-dialog nav{padding:16px;overflow:auto;max-height:calc(100dvh - 165px)}.contents-dialog nav a{display:flex;gap:12px;padding:11px 12px;margin:3px 0;color:var(--muted);text-decoration:none;font-size:13px;line-height:1.5;border-radius:6px}.contents-dialog nav a span{font-size:11px;color:var(--accent);padding-top:2px}.contents-dialog a:hover{background:var(--soft)}.contents-top{display:block;padding:16px 28px;border-top:1px solid var(--line);font-size:13px;text-decoration:none}.section:focus,.guide-heading:focus{outline:none}.footer{padding-bottom:84px}
@media(max-width:760px){.header-actions{gap:6px}.theme-toggle{width:30px;height:30px}.contents-trigger{right:16px;bottom:16px}.term{padding:6px 8px}}
@media print{.theme-toggle,.contents-trigger,.contents-dialog{display:none!important}:root[data-theme]{color-scheme:light;--ink:#202c3c;--muted:#637084;--line:#e0e5ec;--paper:#fff;--bg:#fff;--accent:#315ad9;--soft:#edf2ff;--callout:#f4f7ff}.footer{padding-bottom:20px}}
.footer-credit{max-width:780px;margin-bottom:18px}.footer-credit p{margin:0 0 7px}.footer-credit strong{color:var(--ink);font-size:12px;letter-spacing:.8px;text-transform:uppercase}.footer-note{font-size:11px;line-height:1.6;color:var(--muted)}
.lab-content{font-size:14px;overflow-wrap:anywhere}.lab-content *{font-family:inherit!important;color:inherit!important;line-height:1.7!important}.lab-content span{font-size:inherit!important;background:transparent!important}.lab-content p{font-size:14px!important;margin:0 0 16px!important;text-indent:0!important;text-align:left!important}.lab-content a,.lab-content a *{color:var(--accent)!important}.lab-content img{max-width:100%!important;height:auto!important;border:1px solid var(--line);border-radius:6px}.lab-content ol,.lab-content ul{padding-left:24px!important;margin:16px 0!important}.lab-content table{width:100%!important;border-collapse:separate!important;border-spacing:0!important;border:1px solid var(--line)!important;border-radius:8px;overflow:hidden;margin:20px 0!important}.lab-content td,.lab-content th{padding:12px 16px!important;border:0!important;border-right:1px solid var(--line)!important;border-bottom:1px solid var(--line)!important;background:transparent!important}.lab-content tr:nth-child(odd){background:var(--bg)}.lab-content tr:last-child td{border-bottom:0!important}.lab-content td:last-child{border-right:0!important}
.home-main{padding-bottom:72px}.home-hero{padding:58px 0 34px}.home-hero h1{margin-bottom:14px}.next-card{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:24px 28px;margin-bottom:52px;background:var(--soft);border:1px solid var(--callout-line);border-radius:10px}.next-card h2{margin:0 0 2px;font-size:22px}.next-card p{margin:0;color:var(--muted);font-size:14px}.next-card .section-label{margin-bottom:5px}.next-date{text-align:right;padding-left:24px;border-left:1px solid var(--callout-line)}.next-date span{display:block;color:var(--muted);font-size:11px;text-transform:uppercase;letter-spacing:1px}.next-date strong{display:block;color:var(--accent);font-size:28px;line-height:1.2}.home-section{margin-top:48px}.section-heading{display:flex;justify-content:space-between;align-items:end;gap:20px;margin-bottom:18px}.section-heading h2{margin:0}.section-count{color:var(--muted);font-size:12px}.home-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.home-card{display:flex;align-items:center;gap:16px;min-height:92px;padding:19px 20px;background:var(--paper);border:1px solid var(--line);border-radius:9px;color:var(--ink);text-decoration:none;transition:border-color .15s,transform .15s,box-shadow .15s}.home-card:hover{border-color:var(--accent);transform:translateY(-2px);box-shadow:var(--shadow)}.home-card-active{border-color:var(--accent)}.home-card-locked{cursor:not-allowed;opacity:.62;background:var(--bg)}.home-card-locked:hover{border-color:var(--line);transform:none;box-shadow:none}.card-number{display:grid;place-items:center;width:34px;height:34px;flex:none;background:var(--soft);border-radius:7px;color:var(--accent);font:600 12px/1 ui-monospace,monospace}.card-body{display:block;min-width:0;flex:1}.card-body strong{display:block;font-size:15px}.card-body small{display:block;color:var(--muted);font-size:12px;line-height:1.45;margin-top:4px}.card-arrow,.lock{color:var(--accent);font-size:20px}.lock{color:var(--muted);font-size:24px;transform:rotate(45deg)}.home-card-wide{grid-column:span 2}.home-grid-guides .home-card{min-height:80px}
@media(max-width:760px){.home-hero{padding:38px 0 28px}.next-card{padding:20px;align-items:flex-start}.next-date{padding-left:15px}.home-grid{grid-template-columns:1fr}.home-card-wide{grid-column:auto}.section-heading{display:block}.section-count{display:block;margin-top:7px}}