:root{--ink:#183b3b;--muted:#637572;--green:#146959;--bg:#f5f5ee;--line:#dde5de;--accent:#d5e9a4;--amber:#795520}*{box-sizing:border-box}body{margin:0;background:var(--bg);font:16px/1.85 system-ui,-apple-system,sans-serif;color:var(--ink)}header{min-height:85px;padding:14px 5%;background:#fff;display:flex;align-items:center;justify-content:space-between;gap:20px;border-bottom:1px solid var(--line)}a{color:var(--green);text-underline-offset:4px}a:hover{text-decoration:underline}.brand{display:flex;gap:12px;align-items:center;font-weight:800;font-size:24px;text-decoration:none}.brand small{display:block;font-size:12px;font-weight:400;color:var(--muted)}.mark{background:var(--green);color:#fff;border-radius:15px;width:48px;height:48px;display:grid;place-items:center;font-size:28px}nav{display:flex;gap:22px;font-size:14px}nav a{text-decoration:none}main{max-width:1280px;min-height:70vh;margin:auto;padding:32px 24px}h1{font-size:clamp(30px,5vw,54px);line-height:1.4;margin:15px 0}h2{font-size:25px;line-height:1.5}h3{font-size:19px}p{margin:12px 0}button,.btn{background:var(--green);color:white;border:1px solid transparent;padding:10px 19px;border-radius:10px;cursor:pointer;font:inherit;display:inline-block;text-decoration:none}button:hover,.btn:hover{filter:brightness(.94);text-decoration:none}button:disabled{opacity:.5;cursor:default}.secondary{background:#e8efe7;color:var(--ink)}.outline{background:transparent;border:1px solid var(--line);color:var(--ink)}.active{box-shadow:inset 0 -3px 0 var(--green)}.muted,small{color:var(--muted)}.tag{display:inline-block;font-size:12px;line-height:1.7;padding:3px 10px;border-radius:16px;background:#e7eee5;color:var(--green)}.tag.amber{background:#fff0cf;color:var(--amber)}.hero{display:grid;grid-template-columns:1.4fr .7fr;gap:30px;align-items:center;padding:20px 0 28px}.hero p{font-size:18px;max-width:650px}.hero-visual{background:#e6eddc;border-radius:30px;padding:28px;transform:rotate(-2deg)}.hero-visual .sheet{background:white;border-radius:16px;padding:20px;transform:rotate(2deg);box-shadow:0 8px 30px #183b3b10}.hero-visual .formula{text-align:center;font-size:35px;direction:ltr;color:var(--green)}.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:18px}.card,article,.panel{background:white;border:1px solid var(--line);border-radius:18px;padding:24px}.card{display:flex;flex-direction:column;gap:10px}.card h2{font-size:21px;margin:0}.card p{margin:0}.card .btn{margin-top:auto;align-self:flex-start}.number{font:30px Georgia;color:var(--green)}.stats{display:flex;gap:24px;flex-wrap:wrap;margin:18px 0}.stat b{font-size:27px;display:block;line-height:1.3}.stat span{font-size:12px;color:var(--muted)}.notice{border:1px solid #eadab9;border-right:4px solid #ad813d;padding:14px 17px;background:#fff7e8;border-radius:10px;font-size:14px;margin:14px 0}.notice.info{border-color:#c7dfd3;border-right-color:var(--green);background:#edf5ef}.toolbar{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin:20px 0}.toolbar input[type=search]{flex:1;min-width:180px}input,select,textarea{font:inherit;border:1px solid #bdcbc3;border-radius:9px;padding:10px;background:#fff;color:var(--ink)}input[type=number],input[type=text]{max-width:100%}input[type=range]{width:100%;padding:0;accent-color:var(--green)}input[type=radio],input[type=checkbox]{accent-color:var(--green)}:focus-visible{outline:3px solid #c39432;outline-offset:3px}.layout{display:grid;grid-template-columns:235px minmax(0,1fr);gap:24px}.side{align-self:start;position:sticky;top:18px;background:white;padding:13px;border-radius:15px;border:1px solid var(--line)}.side a{display:block;padding:8px 11px;border-radius:8px;text-decoration:none;font-size:14px}.side a.current{background:var(--green);color:white}.crumb{font-size:13px;color:var(--muted);margin-bottom:15px}.unit{background:white;border:1px solid var(--line);border-radius:14px;margin:14px 0;overflow:hidden}.unit summary{padding:18px 21px;cursor:pointer;font-weight:700;background:#fff}.rows{padding:0 18px 12px}.row{display:flex;align-items:center;justify-content:space-between;gap:15px;border-top:1px solid #eef0e9;padding:13px 0}.row a{font-weight:600;text-decoration:none}.row small{display:block;font-size:12px}.row-end{flex-shrink:0;display:flex;gap:8px;align-items:center}.lessonHead{background:var(--green);color:white;padding:28px;border-radius:20px;margin-bottom:18px}.lessonHead p,.lessonHead small{color:#d9e8df}.lessonHead .tag{background:#e8f2d4;color:#254938}.lessonHead h1{font-size:34px}.lessonNav{display:flex;gap:8px;flex-wrap:wrap;margin:18px 0}.lessonNav button{font-size:14px}.lessonBody{max-width:850px;margin:auto}.formula{font-family:Georgia,serif;font-size:24px;overflow:auto;background:#edf3e7;padding:16px;border-radius:12px;unicode-bidi:plaintext;text-align:center;margin:20px 0}.step{display:flex;gap:12px;padding:14px 0;border-top:1px solid var(--line);align-items:start}.step span{background:#e6f0dc;color:var(--green);border-radius:50%;min-width:30px;text-align:center}.step p{margin:0;unicode-bidi:plaintext}.recall{padding:20px;background:#eef3e6;border-radius:14px;margin:20px 0}details.solution{padding:14px;background:#f5f7f0;border-radius:12px;margin:12px 0}summary{cursor:pointer}fieldset{border:0;padding:0;margin:0}legend{font-size:18px;margin:12px 0}fieldset label.option{display:block;padding:12px;border:1px solid var(--line);border-radius:10px;margin:8px 0;cursor:pointer}fieldset label.option:has(input:checked){background:#eef5e7;border-color:var(--green)}.feedback{padding:12px;border-radius:9px;margin:12px 0;background:#edf3e7}.feedback.bad{background:#fff0e6}.questions .card{display:block;margin:16px 0}.question-actions{display:flex;gap:8px;flex-wrap:wrap;margin:12px 0}.lab{background:#f2f6ea;border-radius:15px;padding:22px;margin:20px 0}.lab-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:18px}.lab output{font-size:24px;font-weight:bold;color:var(--green)}.lab svg{width:100%;max-width:450px;display:block;margin:12px auto}.matrix{display:inline-grid;grid-template-columns:1fr 1fr;gap:10px;direction:ltr;border-inline:2px solid var(--green);padding:10px;max-width:270px}.matrix input{width:90px;text-align:center}.flip{width:100%;background:#edf3e7;color:var(--ink);padding:30px;font-size:20px;min-height:120px}.progress{height:8px;background:#e8eee5;border-radius:10px;overflow:hidden;margin:10px 0}.progress i{display:block;height:100%;background:var(--green)}table{border-collapse:collapse;width:100%;font-size:14px}th,td{padding:12px;text-align:right;border-bottom:1px solid var(--line)}.tablewrap{overflow:auto}footer{padding:25px;text-align:center;font-size:12px;color:var(--muted);border-top:1px solid var(--line)}.empty{text-align:center;padding:30px}.loading{text-align:center;margin:100px 0}.book-solution{border-right:4px solid #8ba877;margin:20px 0;padding-right:15px}.lab .caption{text-align:center;font-size:14px}.checkline{display:flex;align-items:center;gap:8px}.tiny{font-size:12px}pre{white-space:pre-wrap;direction:ltr;text-align:left;background:#f1f4ec;padding:15px;border-radius:10px}.pilltabs{display:flex;flex-wrap:wrap;gap:6px}.pilltabs button{font-size:13px;padding:6px 12px}.error{color:#8e3c25}.last{margin-top:25px;display:flex;justify-content:space-between;gap:12px}.pilltabs .selected,.lessonNav .selected{background:var(--green);color:white}.pilltabs button{background:#eef2e9;color:var(--ink)}.flex{display:flex;justify-content:space-between;align-items:center;gap:15px}.success{color:#146959}.steps-reveal{margin-top:12px}.math-inline{unicode-bidi:plaintext}h1,h2,h3,p{overflow-wrap:anywhere}@media(max-width:750px){header{padding:13px 18px;align-items:flex-start}nav{gap:12px;font-size:12px;max-width:190px;flex-wrap:wrap}.brand{font-size:22px}main{padding:20px 14px}.hero{grid-template-columns:1fr;gap:12px}.hero-visual{display:none}.layout{grid-template-columns:1fr}.side{position:static;display:flex;overflow:auto;gap:5px;white-space:nowrap;padding:8px;max-width:100%}.side a{font-size:12px;flex-shrink:0}.lessonHead{padding:22px}.lessonHead h1{font-size:28px}.card,article{padding:20px}.row{align-items:flex-start}.row-end{flex-direction:column;align-items:flex-end;gap:4px}.row-end .btn{font-size:12px;padding:5px 12px}.stats{gap:22px}.formula{font-size:20px}.toolbar input[type=search]{width:100%}.grid{grid-template-columns:1fr 1fr;gap:12px}.card h2{font-size:18px}.grid .card{padding:17px}.stat b{font-size:23px}button,.btn{font-size:14px}table{min-width:600px}}@media(max-width:400px){.grid{grid-template-columns:1fr}.brand small{font-size:10px}.mark{width:38px;height:38px}nav{max-width:170px}}@media print{header,footer,.side,button,.lessonNav,.toolbar{display:none}.layout{display:block}body{background:white}.card,article{break-inside:avoid}main{max-width:none}}
.learning-path{display:flex;gap:10px;flex-wrap:wrap;margin-bottom:22px}.learning-path span{background:#e7efe5;padding:9px 18px;border-radius:24px;color:#146959;font-weight:700}.lesson-figure{margin:0 0 28px;border:1px solid #d5ded4;border-radius:18px;overflow:hidden;background:#fafbf6}.image-button{padding:0;border:0;background:none;width:100%;cursor:zoom-in}.image-button:hover{background:none}.lesson-figure img{display:block;width:100%;max-height:470px;object-fit:contain}.lesson-figure figcaption{padding:16px;font-size:.95rem}.lesson-figure small{display:block;color:#607167;margin-top:8px}.visual-dialog{max-width:95vw;width:1100px;border:0;border-radius:18px;padding:20px}.visual-dialog::backdrop{background:#162b24c9}.visual-dialog img{width:100%;max-height:75vh;object-fit:contain}.visual-dialog button{float:left}.step-why{background:#edf3e9;padding:12px;border-radius:10px;color:#315e46;font-size:.95rem}.book-card{display:flex;gap:18px;align-items:flex-start}.book-card img{width:110px;height:155px;object-fit:contain;background:#edf0e8;border-radius:5px}.book-card h2{font-size:1.15rem}.book-card>div{min-width:0}.books-grid{grid-template-columns:repeat(auto-fit,minmax(340px,1fr))}.pdf-reader{display:block;width:100%;height:78vh;border:1px solid #cdd8cc;border-radius:12px}article+article{margin-top:22px}@media(max-width:600px){.books-grid{grid-template-columns:1fr}.book-card{gap:12px}.book-card img{width:80px;height:115px}.learning-path{gap:5px}.learning-path span{padding:7px 10px}header nav{flex-wrap:wrap}.lesson-figure figcaption{font-size:.85rem}}
.book-card{flex-direction:row}.book-card p{margin:9px 0}.book-card>div{flex:1}.book-card img{height:170px;width:115px}.book-card h2{line-height:1.65}.books-grid>.book-card{margin:0}@media(max-width:600px){.book-card img{width:80px;height:120px}}
.video-lesson video{width:100%;display:block;aspect-ratio:16/9;background:#173d3c;border-radius:16px;margin:20px 0}.word-guide{border-right:4px solid #b5cb83;padding:5px 18px;margin:25px 0;background:#f5f8ef}.word-guide dl{margin:0}.word-guide dl>div{padding:12px 0;border-top:1px solid #e0e7da}.word-guide dt{font-weight:800;color:#176b59}.word-guide dd{margin:6px 0;line-height:1.9}.visual-guides{display:grid;grid-template-columns:1fr;gap:18px}.visual-guides img{aspect-ratio:16/9;width:100%;object-fit:contain}.worked-example{border-top:1px solid #dde6da;margin-top:24px;padding-top:24px}.worked-example h3{font-size:1.2rem;line-height:1.9}.answer-value{font-size:1.6rem;font-weight:bold;background:#edf3e2;padding:14px;border-radius:12px}.level-1{background:#e2ecf6;color:#315a85}.level-2{background:#fff0d9;color:#835617}.transcript,.scientific-text{padding:16px;border:1px solid #dce5d6;border-radius:12px;margin:20px 0}.transcript summary,.scientific-text summary{cursor:pointer;font-weight:bold}.transcript li{padding:8px 0;line-height:1.9}@media(max-width:600px){.video-lesson video{border-radius:8px}.word-guide{padding:5px 12px}}
.teacher-player{width:100%;aspect-ratio:16/9;border:0;border-radius:12px;display:block;background:#173d3c}.teacher-video{margin:20px 0;gap:14px}.teacher-video h3{line-height:1.7;margin:0}.teacher-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(330px,1fr));gap:20px;margin-top:24px}.teacher-grid .teacher-video{margin:0}.teacher-video .tiny{color:#5d7067}.teacher-video>p{line-height:1.8}.book-audit{margin:24px 0}.book-audit td{vertical-align:top}@media(max-width:600px){.teacher-grid{grid-template-columns:1fr}.teacher-player{border-radius:6px}header nav{gap:9px}}