/* OwlForge：在 base.css（原样复制自 OwlMechanics）之上，只加课程阅读、路线图、作图、练习、测验需要的部分。 */

a.doc, a.logo, .rm-h, .rm-l, .nav-card, .track-list a, .sr, .xref { text-decoration: none; color: inherit; }
.titlebar .logo { color: var(--text); }
.search-btn { display: inline-flex; align-items: center; gap: 7px; height: 30px; padding: 0 8px 0 10px; border-radius: 8px; border: 1px solid var(--line); background: var(--panel); color: var(--text-3); font-size: 12.5px; min-width: 200px; }
.search-btn .kbd { margin-left: auto; }
.search-btn:hover { border-color: var(--line-2); color: var(--text-2); }
.body > .work { min-width: 0; }

/* progress bars */
.pbar { height: 4px; border-radius: 4px; background: var(--bg-2); overflow: hidden; margin-top: 5px; }
.pbar i { display: block; height: 100%; background: var(--ok); border-radius: 4px; transition: width 0.4s; }
.side-prog { display: flex; align-items: center; gap: 8px; margin-top: 8px; font-size: 11.5px; color: var(--text-3); }
.side-prog .pbar { flex: 1; margin: 0; }
.side-prog.big { margin: 10px 0 14px; max-width: 420px; }
.side-prog.big .pbar { height: 6px; }

/* lesson list in the sidebar */
.lesson-item .t { display: flex; align-items: center; gap: 7px; padding-right: 0; }
.lesson-item .d { padding-left: 25px; }
.li-ico { width: 18px; height: 18px; flex: none; display: grid; place-items: center; }
.li-n { width: 18px; height: 18px; border-radius: 50%; border: 1.5px solid var(--line-2); font-size: 10px; display: grid; place-items: center; color: var(--text-3); font-weight: 600; }
.lesson-item.is-done .li-ico { color: var(--ok); }
.doc.on .li-n { border-color: var(--accent); color: var(--accent); }

/* ---------- home / roadmap ---------- */
.home { max-width: 980px; margin: 0 auto; padding: 26px 30px 40px; }
.hero { display: flex; align-items: center; gap: 22px; padding: 22px 24px; border-radius: 18px; background: linear-gradient(135deg, var(--panel-2), var(--bg-2)); border: 1px solid var(--line); }
.hero-logo { width: 84px; height: 84px; border-radius: 20px; flex: none; box-shadow: var(--shadow); }
.hero-t { flex: 1; min-width: 0; }
.hero h1 { margin: 0; font-size: 26px; letter-spacing: -0.01em; }
.hero h1 span { font-size: 15px; color: var(--text-3); font-weight: 500; margin-left: 6px; }
.hero p { margin: 6px 0 0; color: var(--text-2); font-size: 14px; line-height: 1.7; }
.hero-stat { display: flex; flex-direction: column; align-items: center; gap: 6px; font-size: 12px; color: var(--text-3); flex: none; }
.ring { --p: 0; width: 76px; height: 76px; border-radius: 50%; background: conic-gradient(var(--ok) calc(var(--p) * 1%), var(--line) 0); display: grid; place-items: center; }
.ring b { width: 60px; height: 60px; border-radius: 50%; background: var(--panel); display: grid; place-items: center; font-size: 15px; color: var(--text); }
.path-bar { margin: 22px 0 6px; gap: 10px; }
.roadmap { position: relative; padding-left: 4px; }
.rm-group { margin: 22px 0 8px 46px; font-size: 11.5px; font-weight: 650; color: var(--text-3); letter-spacing: 0.08em; }
.rm-track { display: flex; gap: 14px; position: relative; padding-bottom: 12px; }
.rm-track::before { content: ''; position: absolute; left: 15px; top: 34px; bottom: -4px; width: 2px; background: var(--line); }
.rm-track:last-child::before { display: none; }
.rm-dot { width: 32px; height: 32px; border-radius: 50%; flex: none; display: grid; place-items: center; background: var(--panel); border: 2px solid var(--line-2); font-size: 12.5px; font-weight: 650; color: var(--text-2); margin-top: 10px; z-index: 1; }
.rm-track.complete .rm-dot { background: var(--ok); border-color: var(--ok); color: #fff; }
.rm-card { flex: 1; min-width: 0; background: var(--panel); border: 1px solid var(--line); border-radius: 14px; padding: 12px 14px 13px; transition: border-color 0.15s, box-shadow 0.15s; }
.rm-card:hover { border-color: var(--line-2); box-shadow: var(--shadow); }
.rm-h { display: flex; align-items: center; gap: 8px; font-size: 15px; }
.rm-h .ico { color: var(--accent); }
.rm-d { color: var(--text-3); font-size: 12.5px; margin: 3px 0 2px; }
.rm-lessons { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 10px; }
.rm-l { display: inline-flex; align-items: center; gap: 4px; padding: 4px 10px; border-radius: 8px; background: var(--bg-2); color: var(--text-2); font-size: 12.5px; border: 1px solid transparent; transition: all 0.12s; }
.rm-l:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); }
.rm-l.on { background: var(--ok-soft); color: var(--ok); }

/* ---------- lesson page ---------- */
.lesson-wrap { display: flex; gap: 12px; min-height: 100%; }
.lesson-wrap .lesson { flex: 1; min-width: 0; }
.notes.lesson { max-width: 860px; font-size: 15px; line-height: 1.85; padding-top: 26px; }
.lesson h1 { font-size: 28px; line-height: 1.3; margin: 8px 0 14px; letter-spacing: -0.01em; }
.lesson h2 { font-size: 20px; margin: 34px 0 10px; }
.lesson h3 { font-size: 16.5px; margin: 24px 0 8px; }
.lesson h4 { font-size: 15px; margin: 18px 0 6px; }
.lesson p { margin: 10px 0; }
.lesson ul, .lesson ol { padding-left: 24px; margin: 8px 0; }
.lesson li { margin: 4px 0; }
.lesson li.task { list-style: none; margin-left: -22px; display: flex; gap: 7px; align-items: baseline; }
.lesson li.task svg { position: relative; top: 2px; color: var(--text-3); }
.lesson li.task.on svg { color: var(--ok); }
.lesson :not(pre) > code { font: 0.88em var(--mono); background: var(--bg-2); padding: 1.5px 5px; border-radius: 5px; color: var(--accent); }
.lesson mark { background: color-mix(in srgb, var(--warn) 25%, transparent); color: inherit; padding: 0 2px; border-radius: 3px; }
.lesson hr { border: 0; border-top: 1px solid var(--line); margin: 26px 0; }
.lesson img { max-width: 100%; border-radius: 10px; }
.lesson blockquote { margin: 12px 0; padding: 2px 16px; border-left: 3px solid var(--line-2); color: var(--text-2); }
.lesson .lead { font-size: 16px; color: var(--text-2); }
.lesson-meta { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.lesson-meta .muted { display: inline-flex; gap: 4px; align-items: center; }
.lesson-meta a.badge { text-decoration: none; gap: 4px; }
.track-title { display: flex; align-items: center; gap: 10px; }
.track-title .ico { color: var(--accent); }
.table-wrap { overflow-x: auto; margin: 12px 0; }
.lesson table { border-collapse: collapse; font-size: 13.5px; line-height: 1.6; min-width: 50%; margin: 0; }
.lesson th, .lesson td { border: 1px solid var(--line); padding: 6px 11px; vertical-align: top; }
.lesson th { background: var(--panel-2); text-align: left; font-weight: 600; }
.xref { display: inline-flex; align-items: center; gap: 2px; color: var(--blue); border-bottom: 1px dashed currentColor; line-height: 1.3; }
.lesson a:not(.btn):not(.badge):not(.nav-card):not(.xref) { color: var(--blue); }

.lesson-end { margin-top: 40px; padding-top: 20px; border-top: 1px solid var(--line); display: flex; flex-direction: column; gap: 14px; }
.lesson-end [data-done] { align-self: flex-start; height: 36px; padding: 0 16px; }
.lesson-end [data-done].on { background: var(--ok-soft); color: var(--ok); border-color: transparent; }
.lesson-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.nav-card { display: flex; flex-direction: column; gap: 2px; padding: 11px 14px; border: 1px solid var(--line); border-radius: 12px; background: var(--panel); font-size: 14px; line-height: 1.45; }
.nav-card .muted { display: inline-flex; align-items: center; gap: 3px; }
.nav-card:hover { border-color: var(--accent); }
.nav-card.next { text-align: right; align-items: flex-end; }

.toc { width: 200px; flex: none; padding: 30px 8px; position: sticky; top: 0; align-self: flex-start; max-height: 100vh; overflow-y: auto; }
.toc-h { font-size: 11px; font-weight: 650; color: var(--text-3); padding: 0 12px 6px; letter-spacing: 0.06em; }
.toc a { border-left: 2px solid transparent; border-radius: 0 6px 6px 0; }
.toc a.on { border-left-color: var(--accent); color: var(--text); background: var(--hover); }

.track-list { list-style: none; padding: 0 !important; margin: 0; counter-reset: none; }
.track-list li { margin: 0 0 8px !important; }
.track-list a { display: flex; align-items: center; gap: 12px; padding: 11px 14px; border: 1px solid var(--line); border-radius: 12px; background: var(--panel); }
.track-list a:hover { border-color: var(--accent); }
.tl-ico { color: var(--text-3); display: grid; }
.track-list li.on .tl-ico { color: var(--ok); }
.tl-t { flex: 1; display: flex; flex-direction: column; line-height: 1.5; }
.tl-t span { font-size: 12.5px; color: var(--text-3); }

/* callouts */
.lesson .callout { border-radius: 12px; padding: 10px 14px; margin: 14px 0; border: 1px solid transparent; background: var(--panel-2); font-size: 14px; line-height: 1.75; }
.callout-h { display: flex; align-items: center; gap: 7px; }
.callout-b > :first-child { margin-top: 4px; }
.callout-b > :last-child { margin-bottom: 0; }
.callout.c-tip { background: var(--ok-soft); } .callout.c-tip .callout-h { color: var(--ok); }
.callout.c-note, .callout.c-info { background: var(--blue-soft); } .callout.c-note .callout-h, .callout.c-info .callout-h { color: var(--blue); }
.callout.c-warn { background: var(--warn-soft); } .callout.c-warn .callout-h { color: var(--warn); }
.callout.c-danger { background: var(--err-soft); } .callout.c-danger .callout-h { color: var(--err); }
.callout.c-example { background: var(--ai-soft); } .callout.c-example .callout-h { color: var(--ai); }
.callout.c-key { background: var(--accent-soft); } .callout.c-key .callout-h { color: var(--accent); }
details.fold { border: 1px solid var(--line); border-radius: 12px; margin: 14px 0; background: var(--panel); }
details.fold summary { cursor: pointer; padding: 9px 14px; font-weight: 600; font-size: 14px; color: var(--text-2); }
details.fold[open] summary { border-bottom: 1px solid var(--line); }
.fold-b { padding: 4px 16px 8px; }

/* ---------- code ---------- */
.code-box { border: 1px solid var(--line); border-radius: 12px; overflow: hidden; margin: 14px 0; background: var(--panel-2); }
.code-h { display: flex; align-items: center; gap: 6px; padding: 3px 6px 3px 12px; font-size: 11.5px; color: var(--text-3); border-bottom: 1px solid var(--line); background: var(--bg-2); min-height: 30px; }
pre.hl { margin: 0; padding: 12px 14px; overflow-x: auto; font: 13px/1.6 var(--mono); tab-size: 2; }
pre.hl code { font: inherit; background: none; padding: 0; color: var(--text); }
.hl-c { color: var(--text-3); font-style: italic; }
.hl-s { color: #2f8a4f; }
.hl-k { color: #a2398f; font-weight: 550; }
.hl-n { color: #b45f06; }
.hl-f { color: #2f6feb; }
.hl-p { color: #b4462a; }
.hl-t { color: #a2398f; }
.hl-a { color: #b45f06; }
.hl-o { color: var(--text-2); }
:root[data-theme='dark'] .hl-s { color: #8fd18f; }
:root[data-theme='dark'] .hl-k, :root[data-theme='dark'] .hl-t { color: #e59ad8; }
:root[data-theme='dark'] .hl-n, :root[data-theme='dark'] .hl-a { color: #f0b46a; }
:root[data-theme='dark'] .hl-f { color: #82aaff; }
:root[data-theme='dark'] .hl-p { color: #f09a7f; }

/* ---------- editor (textarea over highlighted pre) ---------- */
.ed { position: relative; font: 13px/19.5px var(--mono); }
.ed-hl, .ed-ta { margin: 0; padding: 12px 14px; border: 0; font: inherit; white-space: pre; tab-size: 2; overflow: auto; box-sizing: border-box; width: 100%; }
.ed-hl { position: absolute; inset: 0; pointer-events: none; color: var(--text); }
.ed-hl code { font: inherit; }
.ed-ta { position: relative; display: block; background: transparent; color: transparent; caret-color: var(--text); resize: none; outline: none; min-height: 90px; }
.ed-ta::selection { background: rgba(47, 111, 235, 0.25); color: transparent; }

/* ---------- 动手试试 ---------- */
.try { border: 1px solid var(--line); border-radius: 14px; margin: 18px 0; background: var(--panel); overflow: hidden; box-shadow: var(--shadow); }
.try-h { display: flex; align-items: center; gap: 7px; padding: 6px 8px 6px 12px; border-bottom: 1px solid var(--line); background: var(--panel-2); font-size: 13px; flex-wrap: wrap; }
.try-h > .ico { color: var(--accent); }
.try-b { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
.try-b.js { grid-template-columns: 1fr; }
.try-ed { background: var(--panel-2); border-right: 1px solid var(--line); max-height: 460px; overflow: auto; }
.try-b.js .try-ed { border-right: 0; border-bottom: 1px solid var(--line); }
.try-out { display: flex; flex-direction: column; min-width: 0; }
.pv-frame { width: 100%; border: 0; background: #fff; display: block; flex: 1; min-height: 120px; }
.con { border-top: 1px solid var(--line); background: var(--bg-2); font: 12px/1.55 var(--mono); }
.try-b.js .con { border-top: 0; }
.con.quiet .con-b { display: none; }
.con.quiet .con-h { opacity: 0.6; }
.con-h { display: flex; align-items: center; gap: 6px; padding: 3px 6px 3px 10px; font: 11.5px var(--font); color: var(--text-3); }
.con-b { max-height: 160px; overflow: auto; padding: 2px 0 6px; }
.con-empty { color: var(--text-3); padding: 2px 12px; font-family: var(--font); }
.con-l { display: flex; gap: 6px; padding: 2px 10px; border-top: 1px solid color-mix(in srgb, var(--line) 60%, transparent); white-space: pre-wrap; word-break: break-word; }
.con-l .ico { margin-top: 3px; color: var(--text-3); }
.con-l.error { color: var(--err); background: var(--err-soft); }
.con-l.error .ico { color: var(--err); }
.con-l.warn { color: var(--warn); background: var(--warn-soft); }

/* ---------- playground page ---------- */
.card.play { flex: 1; }
.play-title { width: 180px; font-weight: 600; border-color: transparent; background: transparent; }
.play-title:hover, .play-title:focus { border-color: var(--line); background: var(--panel); }
.play-b { flex: 1; min-height: 0; display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
.play-ed { position: relative; overflow: hidden; border-right: 1px solid var(--line); background: var(--panel-2); }
.play-ed .ed-hl, .play-ed .ed-ta { position: absolute; inset: 0; height: 100%; }
.play-out { display: flex; flex-direction: column; min-height: 0; }
.play-out .pv-frame { height: auto !important; }
.play-out .con-b { max-height: 30vh; }

/* ---------- quiz ---------- */
.quiz { margin: 16px 0; display: flex; flex-direction: column; gap: 10px; }
.quiz-q { border: 1px solid var(--line); border-radius: 14px; padding: 12px 14px; background: var(--panel); }
.quiz-t { display: flex; gap: 9px; font-weight: 600; font-size: 14.5px; line-height: 1.6; }
.quiz-n { width: 22px; height: 22px; flex: none; border-radius: 7px; background: var(--ai-soft); color: var(--ai); display: grid; place-items: center; font-size: 12px; margin-top: 1px; }
.quiz-opts { display: flex; flex-direction: column; gap: 6px; margin: 10px 0 0 31px; }
.quiz-o { display: flex; align-items: flex-start; gap: 8px; text-align: left; padding: 7px 11px; border-radius: 10px; border: 1px solid var(--line); font-size: 14px; line-height: 1.55; background: var(--panel); transition: all 0.12s; }
.quiz-o .ico { margin-top: 3px; color: var(--text-3); }
.quiz-o:hover:not(:disabled) { border-color: var(--ai); background: var(--ai-soft); }
.quiz-o.right { border-color: var(--ok); background: var(--ok-soft); color: var(--ok); }
.quiz-o.right .ico { color: var(--ok); }
.quiz-o.wrong { border-color: var(--err); background: var(--err-soft); color: var(--err); animation: shake 0.3s; }
.quiz-o.wrong .ico { color: var(--err); }
.quiz-o:disabled { cursor: default; }
.quiz-why { margin: 10px 0 0 31px; padding: 8px 12px; border-radius: 10px; background: var(--ok-soft); font-size: 13.5px; line-height: 1.7; }
.quiz-why::before { content: '解析　'; font-weight: 650; color: var(--ok); }
@keyframes shake { 25% { transform: translateX(-4px); } 75% { transform: translateX(4px); } }

/* ---------- figures (js/fig.js) ---------- */
.fig { margin: 18px 0; padding: 0; text-align: center; }
.fig-scroll { overflow-x: auto; padding: 14px 10px; border: 1px solid var(--line); border-radius: 14px; background: var(--panel-2); }
.fig-scroll > svg { max-width: 100%; height: auto; display: block; margin: 0 auto; }
.fig figcaption { font-size: 12.5px; color: var(--text-3); margin-top: 7px; }
.fig-svg text { font-family: var(--font); fill: var(--text); }
.fig-svg .mono { font-family: var(--mono); }
.fig-node rect { fill: var(--panel); stroke: var(--line-2); stroke-width: 1.3; }
.fig-t { font-size: 13.5px; font-weight: 600; }
.fig-sub { font-size: 11.5px; fill: var(--text-3) !important; }
.fig-sub2 { font-size: 12.5px; fill: var(--text-2) !important; }
.fig-edge { stroke: var(--text-3); stroke-width: 1.6; fill: none; }
.fig-edge.dashed { stroke-dasharray: 5 4; }
.fig-arrowhead { fill: var(--text-3); }
.fig-label { font-size: 12px; fill: var(--text-2) !important; }
.fig-label-bg { fill: var(--panel-2); }
.fig-life { stroke: var(--line-2); stroke-width: 1.2; stroke-dasharray: 4 4; }
.fig-note { fill: var(--warn-soft); stroke: color-mix(in srgb, var(--warn) 40%, transparent); }
.fig-note-t { font-size: 12.5px; }
.fig-div { stroke: var(--line-2); stroke-dasharray: 2 3; }
.fig-div-bg { fill: var(--bg-2); }
.fig-div-t { font-size: 12px; fill: var(--text-3) !important; }
.fig-tree-e { stroke: var(--line-2); stroke-width: 1.5; fill: none; }
.fig-seg rect { fill: var(--panel); stroke: var(--line-2); }
.fig-seg-t { font-size: 15px; font-weight: 550; }
.fig-bm-m { fill: color-mix(in srgb, var(--warn) 16%, var(--panel)); stroke: color-mix(in srgb, var(--warn) 50%, transparent); stroke-dasharray: 5 4; }
.fig-bm-b { fill: color-mix(in srgb, var(--text) 22%, var(--panel)); stroke: var(--text-2); }
.fig-bm-p { fill: color-mix(in srgb, var(--ok) 18%, var(--panel)); stroke: color-mix(in srgb, var(--ok) 50%, transparent); }
.fig-bm-c { fill: color-mix(in srgb, var(--blue) 18%, var(--panel)); stroke: var(--blue); }
.fig-box-l { font-size: 11.5px; fill: var(--text-2) !important; font-weight: 600; }
.fig-box-v { font-size: 11.5px; fill: var(--text-2) !important; font-family: var(--mono); }
/* tones */
.fig-node.t-acc rect, .fig-seg.t-acc rect { fill: var(--accent-soft); stroke: var(--accent); }
.fig-node.t-blue rect, .fig-seg.t-blue rect { fill: var(--blue-soft); stroke: var(--blue); }
.fig-node.t-ok rect, .fig-seg.t-ok rect { fill: var(--ok-soft); stroke: var(--ok); }
.fig-node.t-warn rect, .fig-seg.t-warn rect { fill: var(--warn-soft); stroke: var(--warn); }
.fig-node.t-err rect, .fig-seg.t-err rect { fill: var(--err-soft); stroke: var(--err); }
.fig-node.t-ai rect, .fig-seg.t-ai rect { fill: var(--ai-soft); stroke: var(--ai); }
.fig-node.t-mute rect, .fig-seg.t-mute rect { fill: var(--bg-2); stroke: var(--line); }
.fig-node.t-mute text { fill: var(--text-3); }
.fig-edge.t-acc { stroke: var(--accent); } .fig-label.t-acc { fill: var(--accent) !important; }
.fig-edge.t-blue { stroke: var(--blue); } .fig-label.t-blue { fill: var(--blue) !important; }
.fig-edge.t-ok { stroke: var(--ok); } .fig-label.t-ok { fill: var(--ok) !important; }
.fig-edge.t-warn { stroke: var(--warn); } .fig-label.t-warn { fill: var(--warn) !important; }
.fig-edge.t-err { stroke: var(--err); } .fig-label.t-err { fill: var(--err) !important; }
.fig-edge.t-ai { stroke: var(--ai); } .fig-label.t-ai { fill: var(--ai) !important; }
.fig-note.t-blue { fill: var(--blue-soft); } .fig-note.t-ok { fill: var(--ok-soft); } .fig-note.t-err { fill: var(--err-soft); }
/* hand-written ```svg figures can use these classes too */
.fig svg .ink { stroke: var(--text); fill: none; } .fig svg .ink-f { fill: var(--text); }
.fig svg .soft { fill: var(--bg-2); } .fig svg .acc { stroke: var(--accent); } .fig svg .acc-f { fill: var(--accent); }

/* ---------- search ---------- */
.search-in { width: 100%; height: 40px; font-size: 15px; padding: 0 12px; }
.search-res { margin-top: 10px; max-height: 60vh; overflow: auto; display: flex; flex-direction: column; gap: 2px; }
.sr { display: flex; flex-direction: column; gap: 2px; padding: 8px 10px; border-radius: 10px; }
.sr:hover, .sr.on { background: var(--hover); }
.sr-t { display: flex; align-items: center; gap: 7px; }
.sr-t .ico { color: var(--accent); }
.sr-s { font-size: 12.5px; color: var(--text-3); padding-left: 21px; line-height: 1.5; }
.sr mark { background: color-mix(in srgb, var(--warn) 30%, transparent); color: inherit; border-radius: 3px; }

/* ---------- embedded in OwlDiary ---------- */
.app.embedded .titlebar .logo .cn { display: none; }

/* ---------- responsive ---------- */
@media (max-width: 1280px) { .toc { display: none; } }
@media (max-width: 1080px) {
  .body { flex-wrap: nowrap; }
  .work { flex-basis: auto; }
  .card { min-height: calc(100vh - 54px); }
  .card-b { overflow: visible; }
  .play-b { grid-template-columns: 1fr; grid-template-rows: 50vh 50vh; }
  .play-ed { border-right: 0; border-bottom: 1px solid var(--line); }
}
@media (max-width: 760px) {
  .try-b { grid-template-columns: 1fr; }
  .try-ed { border-right: 0; border-bottom: 1px solid var(--line); }
  .hero { display: grid; grid-template-columns: auto 1fr; gap: 14px; padding: 18px; }
  .hero-t { grid-column: 1 / -1; order: 3; }
  .hero-stat { justify-self: end; }
  .ring { width: 60px; height: 60px; } .ring b { width: 47px; height: 47px; font-size: 13px; }
  .hero-logo { width: 60px; height: 60px; border-radius: 14px; }
  .hero-stat { flex-direction: row; }
  .home { padding: 16px 12px 70px; }
  .search-btn { min-width: 0; }
  .lesson-nav { grid-template-columns: 1fr; }
  .rm-group { margin-left: 46px; }
}
@media (max-width: 640px) {
  .body { padding: 0 0 64px; }
  .card { border-radius: 0; border-left: 0; border-right: 0; }
  .notes.lesson { padding: 16px 16px 40px; font-size: 15px; }
  .lesson h1 { font-size: 23px; }
  .hide-sm { display: none; }
}
a.btn { text-decoration: none; color: var(--text); }
a.btn.accent { color: #fff; }
.code-box.output { background: var(--bg-2); }
.code-box.output .code-h { background: transparent; }
.code-box.output pre.hl { color: var(--text-2); }
.con-l.info { color: var(--blue); }
.con-l.info .ico { color: var(--blue); }

/* ---------- groups (rail = 分组；首页「全部」和分组页 = 模块卡片) ---------- */
.rail .grp { margin: -1px 0 5px; }
.side-back { display: inline-flex; align-items: center; gap: 3px; font-size: 12px; color: var(--text-3); text-decoration: none; margin-bottom: 6px; }
.side-back:hover { color: var(--accent); }
.gb-h { display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap; margin: 26px 0 10px; }
.gb-h a { display: inline-flex; align-items: center; gap: 7px; font-size: 16px; color: var(--text); text-decoration: none; }
.gb-h a .ico { color: var(--accent); }
.gb-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 10px; }
.gb-card { display: flex; flex-direction: column; gap: 4px; padding: 12px 14px; border: 1px solid var(--line); border-radius: 14px; background: var(--panel); color: inherit; text-decoration: none; transition: border-color 0.15s, box-shadow 0.15s, transform 0.15s; }
.gb-card:hover { border-color: var(--accent); box-shadow: var(--shadow); transform: translateY(-1px); }
.gb-card.complete { border-color: color-mix(in srgb, var(--ok) 50%, var(--line)); }
.gb-t { display: flex; align-items: center; gap: 7px; font-size: 14.5px; }
.gb-t .ico { color: var(--accent); }
.gb-d { font-size: 12.5px; color: var(--text-3); line-height: 1.55; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; min-height: 2.9em; }
.group-hero { display: flex; gap: 16px; align-items: flex-start; padding: 6px 0 14px; }
.group-hero > .ico { color: var(--accent); margin-top: 6px; }
.group-hero h1 { margin: 0; font-size: 26px; }
.group-hero p { margin: 4px 0 0; }