.learning-entry{display:flex;align-items:center;gap:15px;width:100%;padding:18px 20px;margin:14px 0;border:1px solid var(--stroke);border-radius:18px;background:var(--panel);color:var(--text);font:inherit;text-align:left;cursor:pointer;transition:border-color 200ms,transform 200ms}
.learning-entry>span:nth-child(2){flex:1;display:grid;gap:5px}.learning-entry strong{font-size:17px}.learning-entry small{font-size:12px;color:var(--muted)}.learning-entry:hover{border-color:var(--brand);transform:translateY(-1px)}
.learning-entry{touch-action:manipulation}.learning-entry:active{transform:translateY(1px);border-color:var(--brand)}.learning-entry:focus-visible{outline:3px solid var(--brand);outline-offset:3px}
.learning-entry-wrap{--learning-green:#43b885;--learning-green-wash:color-mix(in srgb,var(--learning-green) 12%,var(--panel));border:1px solid var(--stroke);border-radius:20px;margin:16px 0;overflow:clip;background:var(--panel);color:var(--text)}
.learning-entry-wrap>.learning-entry{margin:0;border:0;border-radius:0;min-height:82px;padding:20px 22px;background:transparent;gap:14px}
.learning-entry-wrap>.learning-entry:hover{transform:none;background:color-mix(in srgb,var(--brand) 4%,var(--panel))}
.learning-entry-wrap>.learning-entry:focus-visible{outline-offset:-4px;border-radius:20px}
.learning-entry-wrap>.learning-entry[aria-expanded=true]{border-bottom:1px solid var(--stroke)}
.learning-entry-chevron{width:22px;height:22px;flex-shrink:0;transition:transform 200ms}.learning-entry[aria-expanded=true] .learning-entry-chevron{transform:rotate(180deg)}
.learning-entry-panel{padding:22px;animation:learning-entry-in 220ms ease-out}.learning-entry-panel[hidden]{display:none!important}
.learning-entry-panel .lesson-grid{grid-template-columns:repeat(5,minmax(0,1fr));gap:10px;margin:0 0 24px}
.learning-entry-panel .learning-lesson{position:relative;isolation:isolate;overflow:hidden;min-width:0;min-height:132px;padding:15px 8px;border-radius:14px;gap:8px}
.learning-entry-panel .learning-lesson[aria-pressed=true]{outline:2px solid var(--brand);outline-offset:2px;background:var(--panel)}
.learning-entry-panel .learning-lesson strong{font-size:13px}.learning-entry-panel .learning-lesson small{font-size:11px;line-height:1.4}
.learning-entry-panel .lesson-icon{width:34px;height:34px}
.learning-entry-panel .learning-units{scroll-margin-top:20px}.learning-entry-panel .learning-units>button{min-height:68px;padding:14px 12px;margin:0;border-radius:10px;gap:10px}
.learning-entry-panel .learning-units>button:focus-visible,.learning-entry-panel .lesson-grid>button:focus-visible{outline:3px solid var(--brand);outline-offset:2px}
.learning-entry-panel .learning-unit-list-heading h2{font-size:18px;margin:0}.learning-entry-panel .learning-units strong{font-size:14px;line-height:1.45}
.learning-entry-loading,.learning-entry-empty{min-height:150px;display:grid;place-content:center;justify-items:center;gap:14px;font-size:14px;color:var(--muted);text-align:center}
.learning-entry-empty p{margin:0;max-width:34ch;line-height:1.6}.learning-entry-panel .learning-empty{min-height:110px}
@keyframes learning-entry-in{from{opacity:0;transform:translateY(-5px)}to{opacity:1;transform:translateY(0)}}
@media(max-width:600px){.learning-entry-wrap>.learning-entry{min-height:76px;padding:17px 16px}.learning-entry-panel{padding:18px 14px}.learning-entry-panel .lesson-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:8px}.learning-entry-panel .learning-lesson{min-height:116px;padding:12px 5px}.learning-entry-panel .learning-unit-list-heading{gap:8px}.learning-entry-panel .learning-unit-list-heading>span{font-size:11px}}
@media(prefers-reduced-motion:reduce){.learning-entry-panel{animation:none}.learning-entry-chevron{transition:none}}
.learning-page{max-width:1080px;margin:auto;padding:0 26px calc(36px + env(safe-area-inset-bottom));color:var(--text);font-family:inherit;overflow-wrap:anywhere}.learning-top{display:flex;align-items:center;gap:14px;position:sticky;top:0;z-index:20;background:var(--bg,#f6f7fb);padding:14px 0;border-bottom:1px solid var(--stroke);min-height:60px}.learning-top>button:nth-child(2){flex:1;text-align:left;border:0;background:transparent;color:inherit;font:inherit;font-weight:700;min-height:44px;cursor:pointer}
.learning-heading{margin:28px 0 24px}.learning-heading>span{font-size:12px;color:var(--muted)}.learning-heading h1{font-size:clamp(24px,4vw,34px);letter-spacing:-.6px;line-height:1.3;margin:10px 0 14px}.learning-heading>p{line-height:1.8;color:var(--muted);max-width:760px}.learning-meta{display:flex;align-items:center;gap:18px;flex-wrap:wrap;font-size:12px;color:var(--muted)}.learning-meta button{border:0;background:transparent;color:var(--brand);font:inherit;min-height:44px;cursor:pointer}
.learning-page .lesson-grid{margin:20px 0 34px}.learning-units{scroll-margin-top:86px}.learning-units h2{font-size:20px}.learning-units>button{display:flex;align-items:center;gap:16px;min-height:80px;width:100%;padding:16px 5px;border:0;border-bottom:1px solid var(--stroke);background:transparent;color:inherit;text-align:left;font:inherit;cursor:pointer;transition:background 200ms}.learning-units>button:hover{background:var(--panel)}.learning-units>button>span:nth-child(2){display:grid;gap:8px;flex:1;min-width:0}.learning-units strong{font-size:15px;font-weight:650}.learning-units small{font-size:12px;color:var(--muted)}.learning-number{font-size:12px;color:var(--brand);font-weight:700;min-width:30px}
.learning-empty,.learning-loading{display:grid;justify-items:center;align-content:center;gap:16px;min-height:280px;text-align:center;color:var(--muted)}.learning-objectives{padding:18px 22px;border-left:3px solid var(--brand);background:var(--panel);border-radius:0 12px 12px 0;font-size:14px;line-height:1.8}.learning-objectives summary{cursor:pointer;font-weight:700;min-height:32px}.learning-jump{display:flex;gap:8px;overflow:auto;padding:16px 0;max-width:100%;scrollbar-width:thin}.learning-jump button{font:inherit;font-size:12px;white-space:nowrap;border:1px solid var(--stroke);border-radius:24px;padding:10px 14px;min-height:44px;background:var(--panel);color:inherit;cursor:pointer}
.learning-reading,.learning-recap,.learning-quiz{max-width:820px;margin-left:auto;margin-right:auto}.learning-section{padding:32px 0;border-bottom:1px solid var(--stroke);scroll-margin-top:105px}.learning-section h2{display:flex;gap:15px;align-items:baseline;font-size:22px;line-height:1.5;margin:0 0 18px}.learning-section h2>span{font-size:12px;color:var(--brand)}.learning-section p,.learning-section li,.learning-recap li{font-size:16px;line-height:1.9}.learning-section ul,.learning-recap ul{padding-left:22px}.learning-section figure{margin:22px 0;padding:18px 22px;border-left:3px solid var(--brand);background:color-mix(in srgb,var(--brand) 7%,var(--panel));border-radius:0 12px 12px 0}.learning-section blockquote{margin:0 0 12px;font-weight:650;line-height:1.8}.learning-section figcaption{color:var(--muted);font-size:14px;line-height:1.8}.learning-hints{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin-top:20px}.learning-hints aside{padding:16px 0}.learning-hints strong{font-size:12px;color:var(--brand)}.learning-hints p{font-size:14px;margin-bottom:0}.learning-recap{padding:25px 0}.learning-recap h2,.learning-quiz h2{font-size:20px}.learning-quiz{scroll-margin-top:100px;padding:24px;border:1px solid var(--stroke);border-radius:18px;background:var(--panel);box-sizing:border-box}.learning-quiz-head{display:flex;align-items:center;justify-content:space-between;gap:16px}.learning-quiz-head>span{font-size:13px;color:var(--muted)}.learning-stem,.learning-quiz blockquote{font-size:16px;line-height:1.9;white-space:pre-wrap}.learning-quiz blockquote{margin:15px 0;padding:16px;background:var(--panel2);border-radius:10px}.learning-choices{display:grid;gap:10px}.learning-choices button{display:flex;align-items:center;gap:12px;padding:15px;border:1px solid var(--stroke);border-radius:12px;font:inherit;background:var(--panel2);color:inherit;text-align:left;min-height:54px;cursor:pointer;line-height:1.6}.learning-choices button>span{flex:1}.learning-choices b{color:var(--muted);font-size:13px}.learning-choices small{font-size:10px}.learning-choices .is-correct{border-color:#29976d;background:#239b7020}.learning-choices .is-wrong{border-color:#cd5864;background:#cd586414}.learning-choices button:disabled{cursor:default}.learning-feedback{margin-top:20px;line-height:1.8}.learning-feedback dl{display:grid;grid-template-columns:24px 1fr;gap:10px;font-size:14px}.learning-feedback dd{margin:0}.learning-feedback dt{font-weight:700}.learning-feedback li{font-size:14px;margin:10px 0}.learning-quiz-nav{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-top:24px}.learning-quiz-nav>span{font-size:12px;color:var(--muted);text-align:center}.learning-score{font-weight:700;text-align:center;margin-top:20px}.learning-bottom-back{display:block;margin:24px auto;min-height:44px}.learning-page :focus-visible{outline:2px solid var(--brand);outline-offset:4px}.learning-page h1:focus{outline:0}
@media(max-width:600px){.learning-page{padding-left:18px;padding-right:18px}.learning-hints{grid-template-columns:1fr;gap:0}.learning-section h2{font-size:20px}.learning-quiz{padding:16px}.learning-quiz-nav{gap:7px}.learning-quiz-nav button{padding:10px}.learning-top{padding-top:max(12px,env(safe-area-inset-top))}}
@media(prefers-reduced-motion:reduce){.learning-entry,.learning-units>button{transition:none;transform:none!important}}
.learning-page{text-align:left}.learning-feedback>strong{display:block}.learning-feedback ul{padding-left:22px}

/* An explicit cross-axis size prevents the long chapter strip from widening
   this flex child beyond the phone viewport. Keep one document scroll. */
body:has(.learning-page)>.topbar{display:none}
#app:has(>.learning-page){padding:0!important;overflow:visible!important;min-height:100vh;min-height:100dvh}
.learning-page{--learning-green:#20835b;--learning-green-wash:color-mix(in srgb,var(--learning-green) 13%,var(--panel));box-sizing:border-box;width:100%;min-width:0;max-width:1080px;margin:0 auto;padding-inline:max(22px,env(safe-area-inset-left)) max(22px,env(safe-area-inset-right));padding-bottom:calc(40px + env(safe-area-inset-bottom));font-size:16px}
.learning-page *, .learning-page *::before,.learning-page *::after{box-sizing:border-box}
.learning-page{--learning-green:#67d6a5}
[data-theme="light"] .learning-page{--learning-green:#20764f}
.learning-top{padding-top:max(12px,env(safe-area-inset-top));min-height:72px;gap:10px}
.learning-top .btn{min-width:44px;min-height:44px}
.learning-top>button:nth-child(2){min-width:0}
.learning-reading,.learning-recap,.learning-quiz,.learning-objectives,.learning-progress{width:100%;max-width:760px;min-width:0;margin-inline:auto}
.learning-heading{max-width:760px;margin-inline:auto}
.learning-heading h1{font-size:clamp(25px,4vw,36px);letter-spacing:-.025em}
.learning-heading>p{font-size:15px;line-height:1.8}
.learning-jump{width:100%;min-width:0;max-width:760px;margin-inline:auto;overscroll-behavior-x:contain}
.learning-jump button{flex-shrink:0}
.learning-progress{display:grid;grid-template-columns:1fr auto;align-items:center;gap:12px;margin-block:20px 26px;font-size:12px;color:var(--muted)}
.learning-progress strong{color:var(--learning-green);font-variant-numeric:tabular-nums}
.learning-progress progress{grid-column:1/-1;appearance:none;border:0;width:100%;height:6px;border-radius:20px;overflow:hidden;background:var(--panel2);color:var(--learning-green)}
.learning-progress progress::-webkit-progress-bar{background:var(--panel2)}
.learning-progress progress::-webkit-progress-value{background:var(--learning-green);border-radius:20px}
.learning-progress progress::-moz-progress-bar{background:var(--learning-green);border-radius:20px}
.learning-page .lesson-grid{grid-template-columns:repeat(5,minmax(0,1fr));gap:12px}
.learning-page .learning-lesson{position:relative;isolation:isolate;overflow:hidden;min-width:0;min-height:150px;padding:18px 8px;gap:9px;transition:border-color 200ms,background-color 200ms}
.learning-lesson::before{content:"";position:absolute;z-index:-1;inset:auto 0 0;height:var(--learning-fill,0%);background:var(--learning-green-wash);transition:height 200ms}
.learning-page .learning-lesson[aria-pressed="true"]{outline:2px solid var(--brand);outline-offset:2px;background:var(--panel)}
.learning-page .learning-lesson small{font-size:11px;line-height:1.6;white-space:normal}
.learning-lesson-progress{font-size:12px;font-weight:700;color:var(--learning-green)}
.learning-unit-list-heading{display:flex;justify-content:space-between;align-items:center;gap:15px;margin-bottom:10px}
.learning-unit-list-heading>span{font-size:12px;color:var(--muted)}
.learning-units>button{padding:18px 14px;border-radius:12px;margin:6px 0;gap:14px}
.learning-units>button.is-complete{background:var(--learning-green-wash);border-color:color-mix(in srgb,var(--learning-green) 30%,transparent)}
.learning-units .is-complete .learning-number,.learning-units .is-complete .learning-unit-status{color:var(--learning-green)}
.learning-unit-status{font-size:12px;font-weight:650;color:var(--muted)}
.learning-section{padding-block:30px;scroll-margin-top:100px}
.learning-section h2{letter-spacing:-.02em;align-items:flex-start}
.learning-section h2>span{padding-top:7px;flex-shrink:0}
.learning-section p,.learning-section li{line-height:1.85;margin-block:14px}
.learning-section figure{padding:18px 20px}
.learning-section.is-read h2>span{color:var(--learning-green)}
.learning-hints{gap:24px}
.learning-hints aside{border-top:1px solid var(--stroke)}
.learning-choices button{min-width:0}
.learning-choices button>span{min-width:0}
.learning-feedback dd{min-width:0}
.learning-bottom-back{width:100%;max-width:760px}
@media(max-width:900px){.learning-page .lesson-grid{grid-template-columns:repeat(3,minmax(0,1fr))}}
@media(max-width:600px){.learning-page{padding-inline:max(16px,env(safe-area-inset-left)) max(16px,env(safe-area-inset-right))}.learning-heading{margin-block:24px}.learning-page .lesson-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.learning-page .learning-lesson{min-height:144px}.learning-objectives{padding:16px}.learning-section figure{padding:16px}.learning-section h2{font-size:21px;gap:10px}.learning-hints{gap:12px}.learning-quiz-nav{flex-wrap:wrap}.learning-quiz-nav>span{flex:1;min-width:70px}.learning-quiz{padding:16px}.learning-units>button{padding-inline:10px}}
@media(prefers-reduced-motion:reduce){.learning-lesson::before,.learning-page .learning-lesson{transition:none}}
.learning-block{padding:18px 20px;margin:22px 0;border-left:3px solid var(--brand);border-radius:0 12px 12px 0;background:var(--panel)}
.learning-block>strong,.learning-example>strong{display:block;font-size:12px;color:var(--muted);margin-bottom:10px}
.learning-block>p{margin:0;white-space:pre-wrap}
.learning-block--warning{border-color:#c89b44;background:color-mix(in srgb,#c89b44 7%,var(--panel))}
.learning-block--formula{font-family:ui-monospace,monospace}
.learning-example ol{padding-left:24px}.learning-example figcaption{font-weight:650;color:var(--text)}
.learning-table{width:100%;max-width:100%;overflow-x:auto;margin:22px 0;border:1px solid var(--stroke);border-radius:12px}
.learning-table table{width:100%;border-collapse:collapse;text-align:left;font-size:14px;line-height:1.7}
.learning-table th,.learning-table td{padding:12px 14px;border-bottom:1px solid var(--stroke);min-width:100px}
.learning-table th{background:var(--panel2);font-weight:650}.learning-table tr:last-child td{border-bottom:0}
.learning-section .learning-graph{padding:16px;border:1px solid var(--stroke);border-radius:12px;background:var(--panel)}
.learning-graph svg{display:block;width:100%;height:auto;max-width:520px;margin:auto;overflow:visible}
.learning-graph text{fill:var(--muted);font-size:13px}.learning-graph-grid{stroke:var(--stroke);stroke-width:1;fill:none}
.learning-graph-axis{stroke:var(--muted);stroke-width:1.3;fill:none}.learning-graph-line{stroke:var(--brand);stroke-width:3;fill:none;stroke-linejoin:round}
.learning-hint{padding:12px 0;margin-bottom:12px;color:var(--muted);font-size:14px;line-height:1.8}.learning-hint summary{cursor:pointer;min-height:44px;display:flex;align-items:center;color:var(--brand)}
@media(max-width:600px){.learning-block{padding:16px}.learning-table th,.learning-table td{padding:10px}}
/* Source-book reader: one responsive card at a time. */
.ln-reader{max-width:760px;margin-inline:auto;min-width:0}.ln-progress{display:flex;justify-content:space-between;gap:8px;flex-wrap:wrap;font-size:12px;color:var(--muted,#929db4);margin:12px 0}.ln-reader>progress{display:block;width:100%;height:4px;accent-color:#45b58a;border:0;margin-bottom:24px}.ln-tabs{display:flex;gap:4px;border-bottom:1px solid #8793ad30;margin:20px 0 16px}.ln-tabs button{flex:1;background:none;border:0;border-bottom:3px solid transparent;border-radius:0;color:inherit;min-height:48px;padding:10px 5px;font:inherit;font-size:14px;font-weight:700}.ln-tabs button[aria-selected=true]{border-bottom-color:#7974ff;color:#7974ff}.ln-position{display:flex;gap:12px;align-items:center;min-width:0;margin:16px 0;scroll-margin-top:80px}.ln-position label{font-size:13px;font-variant-numeric:tabular-nums;white-space:nowrap;color:var(--muted,#929db4)}.ln-position select{min-width:0;flex:1;border:1px solid #8793ad40;border-radius:10px;background:var(--card,#171c29);color:inherit;padding:10px 12px;font:inherit;font-size:14px;min-height:44px}.ln-card{padding:24px;border:1px solid #8793ad30;border-radius:16px;min-width:0;background:var(--card,#171c29)}.ln-card-label{text-transform:none;font-size:12px;letter-spacing:.04em;font-weight:700;color:var(--muted,#929db4);margin-bottom:20px}.ln-card h3{font-size:19px;line-height:1.5;margin:22px 0 12px}.ln-paragraph{line-height:1.85;margin:12px 0;overflow-wrap:anywhere;font-size:16px;user-select:text}.ln-formula{overflow:auto;max-width:100%;padding:12px 4px;line-height:1.8}.ln-formula math{font-size:1.2em}.ln-vector{max-width:100%;overflow:auto;overscroll-behavior-x:contain;background:#fff;border-radius:8px;padding:8px;margin:14px 0;touch-action:pan-x pan-y pinch-zoom}.ln-vector img{display:block;height:auto;max-width:none;flex:none;margin-inline:auto}.ln-warning{border-left:3px solid #d3a44b;padding:12px 16px;background:#d3a44b0d;margin:20px 0}.ln-warning>strong{font-size:13px;color:#d3a44b}.ln-options{display:grid;gap:10px;margin-top:24px}.ln-options>button{display:flex;align-items:center;text-align:left;gap:14px;min-width:0;min-height:52px;width:100%;border:1px solid #8793ad45;border-radius:12px;padding:12px;color:inherit;background:transparent;font:inherit}.ln-options>button>b{flex:none;display:grid;place-items:center;width:30px;height:30px;border-radius:8px;background:#8793ad20}.ln-options>button>div{flex:1;min-width:0}.ln-options .ln-paragraph{margin:0}.ln-options .ln-vector{margin:0}.ln-options>button:disabled{opacity:1}.ln-options>button.is-correct{border-color:#43b38b;background:#43b38b14}.ln-options>button.is-wrong{border-color:#d96e78;background:#d96e7814}.ln-options small{font-size:10px}.ln-result{font-weight:700;margin:20px 0}.ln-solution-toggle{display:block;width:100%;text-align:left;min-height:48px;padding:12px 0;border:0;border-top:1px solid #8793ad30;background:none;color:inherit;font:inherit;font-weight:700;margin-top:22px}.ln-solution{border-left:3px solid #7974ff;padding-left:16px;margin:10px 0 22px;min-width:0}.ln-nav{display:flex;justify-content:space-between;gap:12px;margin:20px 0}.ln-nav button{min-height:48px}.ln-loading{min-height:300px;display:flex;align-items:center;justify-content:center;gap:12px}.ln-open-label,.ln-saving{font-size:13px;color:var(--muted,#929db4)}.ln-reader button:focus-visible,.ln-reader select:focus-visible,.ln-reader [tabindex]:focus-visible{outline:2px solid #7974ff;outline-offset:3px}.ln-reader button:not(:disabled){cursor:pointer}.ln-reader button{transition:background .2s,border-color .2s}.ln-reader button:disabled{cursor:default}.ln-reader .learning-empty button{display:block;margin:16px auto}
html[data-theme=light] .ln-card,html[data-theme=light] .ln-position select{background:#fff;color:#1d2941}html[data-theme=light] .ln-paragraph{color:#28354a}html[data-theme=light] .ln-card-label,html[data-theme=light] .ln-progress{color:#58647a}
@media(max-width:480px){.ln-card{padding:18px 14px}.ln-tabs button{font-size:12px}.ln-paragraph{font-size:16px;line-height:1.8}.ln-reader .learning-heading h1{font-size:25px}.ln-solution{padding-left:10px}.ln-options>button{gap:8px}}
@media(prefers-reduced-motion:reduce){.ln-reader button{transition:none}}
/* All subjects start fitted to the page; native pinch magnifies the reader. */
.learning-page,.learning-page button,.learning-page .ln-vector,.learning-page .ln-formula,.learning-page .learning-table{touch-action:pan-x pan-y pinch-zoom}
.learning-page .ln-vector{overflow:clip;overscroll-behavior:auto}
.learning-page .ln-vector img{max-width:100%;height:auto}
.learning-page .ln-formula,.learning-page .learning-table{overflow:clip}
.learning-page .learning-fit{position:relative;padding:0;min-width:0;max-width:100%;overflow:clip}
.learning-fit-content{width:max-content;max-width:none;transform-origin:top left}
.learning-fit-content>math{padding:12px 4px}
.learning-fit-content>table{width:max-content;min-width:0}
.learning-page .learning-fit-content .ln-vector{max-width:none}
/* Native theory and original, untampered source question crops. */
.ln-reader .learning-heading h1{color:#176f76;font-size:clamp(27px,4vw,38px);line-height:1.2}
.ln-card h3{color:#7150a3;font-size:19px;font-weight:750}
html:not([data-theme=light]) .ln-reader .learning-heading h1{color:#78c9c6}
html:not([data-theme=light]) .ln-card h3{color:#b7a0e8}
.ln-card-label{display:flex;align-items:center;justify-content:space-between;gap:12px}
.ln-solved-badge{font-size:11px;font-weight:750;letter-spacing:0;color:var(--learning-green,#379d77);border:1px solid currentColor;border-radius:20px;padding:4px 8px;white-space:nowrap}
.qs-source-image{box-sizing:border-box;width:100%;min-width:0;max-width:100%;padding:14px;margin:12px 0 20px;border-radius:12px;background:#fff;color:#111;touch-action:pan-x pan-y pinch-zoom}
.qs-source-image img{display:block;width:100%;max-width:100%;height:auto;object-fit:contain;margin:auto;touch-action:pan-x pan-y pinch-zoom}
.ln-letter-options{grid-template-columns:repeat(5,minmax(0,1fr));gap:10px;margin-top:18px}
.ln-letter-options>button{position:relative;display:flex;justify-content:center;align-items:center;gap:4px;padding:12px 4px;min-height:54px;border-width:2px;font-size:18px;font-weight:750}
.ln-letter-options>button>b{background:transparent;width:auto;height:auto}
.ln-letter-options>button>small{font-size:16px;line-height:1}
.ln-letter-options>button:not(:disabled):hover{border-color:#8a70bb;background:#8a70bb10}
.ln-letter-options>button.is-correct{color:#198455;background:#45b58a17;border-color:#45b58a}
.ln-letter-options>button.is-wrong{color:#d46573;border-color:#d46573}
html:not([data-theme=light]) .ln-letter-options>button.is-correct{color:#75d9ad}
.ln-solution-toggle{display:flex;align-items:center;justify-content:space-between;color:#8360ba}
.ln-nav .ln-stage-next{width:auto;margin:0;min-height:48px}
.ln-embedded{padding-top:24px;margin-top:24px;border-top:1px solid var(--stroke,#8793ad40)}
.ln-saving{display:flex;align-items:center;gap:10px;min-height:24px}
.ln-saving .qq-loader{width:18px;height:18px}
.ln-table .ln-paragraph{font-size:inherit;line-height:inherit;margin:0}.ln-table .qs-source-image{padding:8px;margin:4px 0}.ln-table .ln-figure{margin:0}.ln-card-sidebar{border-left:3px solid #9378bd}.ln-card-sidebar .ln-card-label{color:#b7a0e8}html[data-theme=light] .ln-card-sidebar .ln-card-label{color:#7150a3}
.ln-table{margin:20px 0;max-width:100%;border:1px solid var(--stroke,#8793ad40);border-radius:12px;overflow:hidden}.ln-table table{width:100%;table-layout:fixed;border-collapse:collapse;text-align:left;font-size:14px;line-height:1.6}.ln-table th,.ln-table td{padding:12px;overflow-wrap:anywhere;border-bottom:1px solid var(--stroke,#8793ad40);vertical-align:top}.ln-table th{background:var(--panel2,#8793ad15);font-weight:700}.ln-table caption{padding:12px;font-weight:700;text-align:left}.ln-table tr:last-child td{border-bottom:0}.ln-table-compact td{font-weight:600;text-align:center;vertical-align:middle}.ln-sidebar{border-left:3px solid #9378bd;background:#9378bd0b;padding:4px 16px;margin:24px 0}.ln-caption{font-size:13px;color:var(--muted);line-height:1.6;margin:8px 0 20px}.ln-context>span{display:block;font-size:12px;color:var(--muted);font-weight:650;margin-top:16px}.ln-stage-next{width:100%;margin-bottom:16px;min-height:48px}.ln-reader .qs-source-image[role=button]{cursor:zoom-in}.ln-figure{min-width:0;max-width:100%}.dd-annotation-stage .qs-source-image{margin:12px 0 20px}
@media(max-width:560px){.ln-table th,.ln-table td{padding:10px;font-size:13px}.ln-table-compact td{padding:8px 3px;font-size:clamp(11px,3vw,13px);overflow-wrap:normal;word-break:normal}.ln-table-stack table,.ln-table-stack tbody,.ln-table-stack tr,.ln-table-stack td{display:block}.ln-table-stack thead{position:absolute;width:1px;height:1px;clip-path:inset(50%);overflow:hidden}.ln-table-stack tr{padding:6px 12px;border-bottom:1px solid var(--stroke,#8793ad40)}.ln-table-stack tr:last-child{border:0}.ln-table-stack td{border:0!important;padding:8px 0}.ln-table-stack td::before{content:attr(data-label);display:block;font-size:12px;font-weight:750;color:var(--muted);margin-bottom:3px}.ln-sidebar{padding-inline:12px}}
@media(max-width:560px){.is-history .ln-table:not(.ln-table-compact) table,.is-history .ln-table:not(.ln-table-compact) tbody,.is-history .ln-table:not(.ln-table-compact) tr,.is-history .ln-table:not(.ln-table-compact) td{display:block}.is-history .ln-table:not(.ln-table-compact) thead{position:absolute;width:1px;height:1px;clip-path:inset(50%);overflow:hidden}.is-history .ln-table:not(.ln-table-compact) tr{padding:8px 12px;border-bottom:1px solid var(--stroke,#8793ad40)}.is-history .ln-table:not(.ln-table-compact) tr:last-child{border:0}.is-history .ln-table:not(.ln-table-compact) td{border:0;padding:5px 0;font-size:14px;line-height:1.6}.is-history .ln-table:not(.ln-table-compact) td:first-child{font-weight:700;color:#b7a0e8}.is-history .ln-table:not(.ln-table-compact) td::before{content:attr(data-label);display:block;font-size:12px;font-weight:750;color:var(--muted);margin-bottom:3px}.is-history .ln-table:not(.ln-table-compact) td[data-label=""]::before{display:none}}
@media(max-width:560px){html[data-theme=light] .is-history .ln-table:not(.ln-table-compact) td:first-child{color:#7150a3}}
.is-physics .math-term{display:inline-block;vertical-align:middle;max-width:100%;min-width:0}
.is-physics .ln-paragraph math{font-size:1.28em;line-height:1.25}
.is-geometry .ln-paragraph math{font-size:1.18em;line-height:1.3}
.is-geometry .ln-figure{max-width:100%}
.is-geometry .ln-figure .qs-source-image{margin:10px 0 16px}
.ln-workspace{margin:16px 0 22px}
.ln-workspace .cg-paper{width:100%;border-radius:12px}
.ln-workspace .cg-paper-area:not([hidden]){display:flex;flex-direction:column}
.ln-workspace .cg-paper-tools{position:relative;flex:none;flex-wrap:wrap;align-items:center;gap:3px;padding:4px;border-bottom:1px solid #d4dbe5;background:#fff}
.ln-workspace .cg-paper-tools button{flex:none;min-width:44px;min-height:44px}
.ln-workspace .cg-paper-width{display:flex;align-items:center;gap:5px;margin-inline:auto 0;font-size:11px;font-weight:650;color:#42516a}
.ln-workspace .cg-paper-width select{min-height:44px;min-width:68px;padding:5px;border:1px solid #d4dbe5;border-radius:8px;background:#fff;color:#25334b;font:inherit}
.ln-workspace .cg-paper-canvas{flex:1 1 auto;min-height:0;height:auto}
.ln-workspace .cg-paper-handle{min-height:48px}
.ln-workspace .cg-paper-width select:focus-visible{outline:2px solid #6d7bd0;outline-offset:2px}
@media(max-width:560px){.ln-workspace .cg-paper-tools{display:grid;grid-template-columns:repeat(5,minmax(0,1fr))}.ln-workspace .cg-paper-width{grid-column:1 / span 4;justify-content:flex-start;margin-left:0}.ln-workspace .cg-paper-tools .cg-paper-close{grid-column:5;margin-left:0}}
.qs-dialog:has(.qs-source-image){touch-action:pan-x pan-y pinch-zoom}
.qs-dialog .qs-source-image{margin:0}
@media(max-width:480px){.qs-source-image{padding:10px 6px}.ln-letter-options{gap:7px}.ln-letter-options>button{font-size:17px;min-height:52px}}

.is-biology .ln-figure{max-width:100%;min-width:0}.is-biology .ln-figure .qs-source-image{margin:10px 0 16px}.is-biology .ln-paragraph{overflow-wrap:anywhere}.is-biology .ln-table table{max-width:100%}

.ln-quote{margin:18px 0;padding:12px 18px;border-left:3px solid #8b73b6;background:#8b73b60b;font-size:16px;line-height:1.8;font-style:italic;overflow-wrap:anywhere}.is-philosophy .ln-table table{max-width:100%}.is-philosophy .ln-figure{min-width:0;max-width:100%}@media(max-width:480px){.ln-quote{padding:10px 12px}}

/* Native source books: preserve editorial emphasis in a small, accessible brand palette. */
.ln-reader{--ln-teal:#7ad8bd;--ln-violet:#c4abf2;--ln-blue:#98bdf8;--ln-warm:#eec18d}
html[data-theme=light] .ln-reader{--ln-teal:#146d5d;--ln-violet:#684390;--ln-blue:#24549b;--ln-warm:#965420}
.ln-card--theory{box-shadow:inset 0 3px var(--ln-teal)}
.ln-card--question{box-shadow:inset 0 3px var(--ln-blue)}
.ln-reader .ln-card h3.ln-heading{letter-spacing:-.015em;overflow-wrap:anywhere}
.ln-reader .ln-card h3.ln-heading--major{font-size:clamp(19px,2.3vw,23px);line-height:1.35;color:var(--ln-teal);border-bottom:1px solid color-mix(in srgb,var(--ln-teal) 35%,transparent);padding:0 0 11px;margin:28px 0 14px}
.ln-reader .ln-card h3.ln-heading--major::before{content:"";display:inline-block;width:4px;height:.93em;background:currentColor;border-radius:4px;margin-right:10px;vertical-align:-.08em}
.ln-reader .ln-card h3.ln-heading--minor{font-size:17px;line-height:1.45;color:var(--ln-violet);margin:22px 0 9px}
.ln-reader .ln-card h3.ln-heading--minor::before{content:"";display:inline-block;width:7px;height:7px;border-radius:50%;background:currentColor;margin-right:10px;vertical-align:.16em}
.ln-reader :is(.ln-paragraph,.ln-quote,.ln-table) :is(strong,b){color:var(--ln-teal);font-weight:750}
.ln-reader :is(.ln-paragraph,.ln-quote,.ln-table) em{color:var(--ln-violet)}
.ln-reader .ln-tone-violet{color:var(--ln-violet);font-weight:700}
.ln-reader .ln-tone-warm{color:var(--ln-warm);font-weight:700}
.ln-reader .ln-tone-blue{color:var(--ln-blue);font-weight:700}
.ln-reader .ln-tone-teal{color:var(--ln-teal);font-weight:700}
.ln-reader :is(.ln-tone-violet,.ln-tone-warm,.ln-tone-blue,.ln-tone-teal) :is(strong,b,em){color:inherit}
.ln-reader .ln-quote{border-color:var(--ln-violet);background:color-mix(in srgb,var(--ln-violet) 7%,transparent)}
.ln-reader .ln-table th{color:var(--ln-blue)}
@media(max-width:480px){.ln-reader .ln-card h3.ln-heading--major{font-size:19px}.ln-reader .ln-card h3.ln-heading--minor{font-size:16px}}

/* The earlier Turkish reader uses the same restrained hierarchy. */
.learning-page{--ln-teal:#7ad8bd;--ln-violet:#c4abf2;--ln-blue:#98bdf8}
html[data-theme=light] .learning-page{--ln-teal:#146d5d;--ln-violet:#684390;--ln-blue:#24549b}
.learning-page .learning-section h2{color:var(--ln-teal)}
.learning-page .learning-section :is(p,li) :is(strong,b){color:var(--ln-teal)}
.learning-page .learning-section :is(p,li) em{color:var(--ln-violet)}
.learning-page .learning-section figure{border-left-color:var(--ln-violet)}
.learning-page .learning-section figure blockquote{color:var(--ln-violet)}
.ln-inline-vector{display:inline-block;vertical-align:-.3em;line-height:0;max-width:100%}
.ln-inline-vector img{display:block;max-width:100%;object-fit:contain;filter:brightness(0) invert(1)}
[data-theme="light"] .ln-inline-vector img{filter:none}