:root{--bg:#0a1015;--panel:#111920;--ink:#edf2f1;--muted:#a5b0b5;--line:#29343c;--cyan:#72c7cc}
html{scroll-padding-top:140px}
.theme-top-links{display:flex;gap:20px;align-items:center;margin-left:auto}
.theme-top-links a{color:var(--muted);font:600 12px/1.4 "SFMono-Regular",Menlo,monospace;text-decoration:none;white-space:nowrap}
.theme-top-links a:hover{color:var(--cyan)}
.theme-top-links .theme-switch{display:inline-flex;align-items:center;min-height:35px;padding:6px 10px;border:1px solid var(--line);border-radius:5px;color:var(--muted);font:600 12px/1.35 "SF Pro Text",-apple-system,"PingFang SC",sans-serif}
.theme-top-links .theme-switch.selected{border-color:var(--cyan);background:#183039;color:var(--ink)}
.course-breadcrumb{display:flex;align-items:center;gap:8px;min-height:46px;padding-top:17px;color:var(--muted);font-size:12px;overflow-x:auto;white-space:nowrap}
.course-breadcrumb a{color:var(--cyan);text-decoration:none}
.course-breadcrumb span:last-child{color:var(--ink)}
.index-hero{padding-top:47px}
.index-hero h1{font-size:clamp(44px,5.6vw,72px)}
.course-intro-strip{display:grid;grid-template-columns:150px minmax(0,1fr);gap:20px;padding:25px 0 30px;border-bottom:1px solid var(--line)}
.course-intro-strip strong{color:var(--cyan);font:700 12px/1.5 "SFMono-Regular",Menlo,monospace}
.course-intro-strip p{margin:0;color:var(--muted);max-width:67ch;font-size:14px}
.theme-filters{position:sticky;top:125px;z-index:8;background:rgba(10,16,21,.97);padding:18px 0;margin:0}
.theme-filters a{background:#152029}
.topic-group{scroll-margin-top:190px}
.topic-group .group-label h2{font-size:25px;line-height:1.3;letter-spacing:-.03em;margin:0 0 11px}
.topic-row{min-height:107px}
.course-after{border-top:1px solid var(--line);padding:38px 0 70px}
.course-after h2{font-size:24px;margin:0 0 9px}
.course-after p{color:var(--muted);max-width:65ch}
.course-after a{display:inline-flex;min-height:41px;align-items:center;padding:7px 12px;border:1px solid var(--cyan);border-radius:5px;text-decoration:none;font-size:13px}
.lesson-head{padding-top:35px}
.lesson-head h1{max-width:20ch}
.lesson-grid{padding-top:32px}
.lesson-article{max-width:73ch}
.lesson-article ol{padding-left:1.4em}
.lesson-article li{margin-bottom:13px}
.lesson-article h2{margin-top:50px}
.lesson-source{margin-top:50px;padding:20px 23px;border:1px solid var(--line);border-left:3px solid var(--cyan);background:#101c22;border-radius:5px}
.lesson-source strong{color:var(--cyan);font:700 11px "SFMono-Regular",Menlo,monospace}
.lesson-source p{font-size:13px;margin:9px 0 0}
.legacy-panel{max-width:760px;padding:80px 0 120px}
.legacy-panel h1{font-size:clamp(40px,5vw,66px);line-height:1.13;letter-spacing:-.05em;margin:0 0 22px}
.legacy-panel>p:not(.kicker){color:var(--muted);font-size:16px;line-height:1.8;max-width:63ch}
.legacy-panel .primary-action{margin-top:15px}
.legacy-secondary{margin-top:23px}
.current{color:var(--cyan)!important}
@media(max-width:900px){.theme-filters{top:118px}.course-intro-strip{grid-template-columns:1fr;gap:6px}}
@media(max-width:620px){.topbar-inner{flex-wrap:wrap;padding:8px 0}.theme-top-links{width:100%;gap:8px;justify-content:space-between}.theme-top-links a{font-size:11px}.theme-top-links a:first-child{display:none}.theme-top-links .theme-switch{flex:1;justify-content:center;font-size:11px;white-space:normal;text-align:center}.course-breadcrumb{font-size:11px}.course-breadcrumb span{max-width:32vw;overflow:hidden;text-overflow:ellipsis}.index-hero{padding-top:25px}.theme-filters{top:152px;overflow-x:auto}.topic-group{scroll-margin-top:205px}.legacy-panel{padding:50px 0 85px}.lesson-article h2{margin-top:40px}}