@font-face{font-family:system-fallback;src:local('Tahoma')}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:130px}body{--bg:#05191f;--panel:#0d2d35;--panel2:#11363f;--line:rgba(116, 212, 210, 0.16);--text:#c6d9d9;--heading:#eef8f6;--muted:#a0b9bc;--accent:#68d8d2;--accent-text:#68d8d2;--action:#68d8d2;--ink:#05191f;--blue:#72c4d2;--secondary-fill:#123844;--secondary-ink:#72c4d2;--wrong:#ef8f8f;--good:#55d69d;--shadow:0 20px 54px rgba(0, 7, 10, 0.27);--nav-bg:linear-gradient(135deg, rgba(8, 32, 40, 0.95), rgba(10, 44, 51, 0.95));--hero-a:#041c23;--hero-b:#062f39;--hero-c:#07474c;background:var(--bg);color:var(--text);margin:0;font:16px/1.8 Tahoma,Arial,sans-serif;padding-bottom:calc(94px + env(safe-area-inset-bottom))}html[data-theme=light] body{--bg:#e8f0ed;--panel:#f0f5f1;--panel2:#f6f8f4;--line:rgba(0, 66, 84, 0.14);--text:#244e56;--heading:#063943;--muted:#526f75;--accent:#00888c;--accent-text:#006b73;--action:#006b73;--ink:#f6f8f4;--blue:#006b73;--secondary-fill:#d4e7ec;--secondary-ink:#006b73;--wrong:#b84d4d;--good:#0f8b62;--shadow:0 18px 50px rgba(5, 58, 66, 0.085);--nav-bg:linear-gradient(135deg, rgba(246, 249, 245, 0.96), rgba(226, 239, 235, 0.96));--hero-a:#d5e9e5;--hero-b:#edf3ee;--hero-c:#dce9ee;}a{color:inherit;text-decoration-thickness:1px;text-underline-offset:4px}button,input,select,textarea{font:inherit;color:inherit}button,a,select{-webkit-tap-highlight-color:transparent}button,select{cursor:pointer}button:disabled{opacity:.45;cursor:default}button:focus-visible,a:focus-visible,select:focus-visible,input:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid var(--blue);outline-offset:4px}button{touch-action:manipulation}input,select,textarea{background:var(--panel2);border:1px solid var(--line);border-radius:12px;padding:10px 12px;min-height:46px;max-width:100%;font-size:16px}textarea{width:100%;min-height:110px;resize:vertical}input[type=checkbox]{accent-color:var(--accent-text);width:21px;min-height:21px;flex:none}h1,h2,h3,p{margin:0}h1{font-size:clamp(28px,5vw,48px);line-height:1.35;letter-spacing:-1px}h2{font-size:24px;line-height:1.5}h3{font-size:19px;line-height:1.6}p+p{margin-top:12px}.muted,.source,.small{color:var(--muted)}.small{font-size:13px}.en{display:block;direction:ltr;text-align:start;color:var(--muted);font-family:Arial,sans-serif;font-size:.89em;line-height:1.55;margin-top:5px;letter-spacing:0}.label{font:700 11px/1.5 Arial,sans-serif;letter-spacing:2px;color:var(--accent-text);direction:ltr;display:inline-block}.top{background:var(--bg);border-bottom:1px solid var(--line)}.top-inner{max-width:1180px;margin:auto;display:flex;justify-content:space-between;align-items:center;padding:17px 28px;gap:12px}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;font-size:27px;font-weight:700;line-height:1.4}.brand small{display:block;font:9px/1.6 Arial,sans-serif;letter-spacing:1.6px;color:var(--muted)}.mark{display:grid;place-items:center;background:var(--action);color:var(--ink);border-radius:15px;width:49px;height:49px;font-size:31px;font-weight:900}.row{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.between{justify-content:space-between}.icon-btn{border:1px solid var(--line);border-radius:12px;width:46px;height:46px;background:var(--panel2);font-size:24px}.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:11px 20px;border:1px solid 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.phase:last-child{border:0}.phase b{font:700 30px/1 Arial;color:var(--accent-text)}.grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.grid.three{grid-template-columns:repeat(3,minmax(0,1fr))}.card{padding:25px;border:1px solid var(--line);border-radius:22px;background:var(--panel);box-shadow:var(--shadow);min-width:0}.course{position:relative;overflow:hidden}.course .course-top{display:flex;justify-content:space-between;gap:12px;align-items:flex-start;margin-bottom:25px}.course-badge{font:700 15px/1 Arial;background:var(--action);color:var(--ink);border-radius:13px;padding:16px}.course.blue .course-badge{background:var(--blue)}.course h2{margin-bottom:12px}.course .row{margin-top:20px}.section-title{display:flex;align-items:center;justify-content:space-between;gap:12px;margin:28px 0 14px}.stats{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px;margin:20px 0}.stat{background:var(--panel2);padding:17px;border-radius:17px}.stat 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h3{margin-top:20px;margin-bottom:9px}.lesson-content h3 .en{font-size:.8em}.lesson-content .callout h3{margin-top:0}.lesson-layout{display:grid;grid-template-columns:240px minmax(0,1fr);gap:22px}.lesson-aside{align-self:start;position:sticky;top:90px}.lesson-aside button{display:block;width:100%;text-align:start;padding:12px;border:0;border-radius:10px;background:transparent;color:var(--muted);margin-bottom:4px;font-size:14px}.lesson-aside button.active{background:var(--panel2);color:var(--text);border-inline-start:3px solid var(--accent)}.lesson-picker{display:none}.lesson-title{margin-bottom:22px}.source{font-size:12px;margin-top:20px}.source a{color:var(--blue)}.recall{border:1px dashed var(--accent);padding:21px;border-radius:16px;margin:25px 0}.recall details{margin-top:15px}summary{cursor:pointer;min-height:42px;line-height:1.8;font-weight:700;padding-block:5px}details>p,details>.row{margin-top:12px}table{width:100%;border-collapse:collapse;min-width:420px;font-size:14px}td,th{border-bottom:1px solid var(--line);padding:13px 12px;text-align:start;vertical-align:top}th{color:var(--accent-text);background:var(--panel2)}.table-scroll{overflow:auto;margin:20px 0;max-width:100%;border:1px solid var(--line);border-radius:12px}pre{direction:ltr;text-align:left;overflow:auto;background:var(--bg);padding:18px;border-radius:12px;font:14px/1.8 Consolas,monospace;max-width:100%}li{margin:10px 0}ol{padding-inline-start:25px}.field{display:grid;gap:7px}.field label{font-size:13px;color:var(--muted)}.fields{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px}.fields.two{grid-template-columns:repeat(2,minmax(0,1fr))}.scope-course{margin-bottom:20px}.scope-chapter{padding:15px 0;border-top:1px solid var(--line)}.scope-items{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin-top:14px}.check-label{display:flex;align-items:center;gap:12px;border:1px solid var(--line);border-radius:12px;padding:12px;font-size:14px;background:var(--panel2);cursor:pointer}.scope-summary{position:sticky;bottom:90px;background:var(--panel);padding:15px 20px;border:1px solid var(--accent);border-radius:17px;z-index:5}.progress{height:6px;background:var(--line);border-radius:9px;overflow:hidden;margin:16px 0}.progress>span{display:block;height:100%;background:var(--action);border-radius:9px}.question-card{max-width:820px;margin:auto}.question-card h2{font-size:23px;margin:23px 0}.option{display:flex;align-items:center;gap:13px;text-align:start;width:100%;padding:16px;border:1px solid var(--line);background:var(--panel2);border-radius:14px;margin-bottom:10px;line-height:1.65}.option .letter{display:grid;place-items:center;width:30px;height:30px;border:1px solid var(--line);border-radius:9px;flex:none;font:700 13px Arial}.option.selected{border-color:var(--blue);box-shadow:0 0 0 1px var(--blue)}.option.correct{border-color:var(--good)}.option.wrong{border-color:var(--wrong)}.option:disabled{opacity:1;cursor:default}.feedback{border:1px solid var(--good);border-radius:15px;padding:18px;margin:18px 0}.feedback.wrong{border-color:var(--wrong)}.feedback h3{margin-bottom:10px;color:var(--good)}.feedback.wrong h3{color:var(--wrong)}.exam-clock{font:700 22px Arial;color:var(--accent-text)}.numbers{display:flex;gap:7px;flex-wrap:wrap;margin:20px 0}.numbers button{border:1px solid var(--line);border-radius:9px;min-width:40px;min-height:40px;background:var(--panel2);color:var(--text)}.numbers button.answered{background:var(--blue);color:var(--ink)}.numbers button.current{outline:2px solid var(--accent);outline-offset:1px}.score-circle{width:120px;height:120px;border:7px solid var(--accent);border-radius:50%;display:grid;place-items:center;font:700 36px Arial;margin:auto}.flash{max-width:800px;margin:auto;min-height:330px;display:flex;flex-direction:column;justify-content:center;text-align:center}.flash h2{margin:22px 0;font-size:25px}.flash .answer{text-align:start;margin-top:20px}.flash-actions{display:flex;justify-content:center;gap:10px;flex-wrap:wrap;margin-top:22px}.pill{display:inline-block;font-size:11px;background:var(--panel2);padding:4px 10px;border:1px solid var(--line);border-radius:16px;color:var(--muted)}.search-result{display:block;padding:17px;text-decoration:none;border-bottom:1px solid var(--line)}.search-result:last-child{border:0}.empty{text-align:center;padding:40px 20px;color:var(--muted)}.lab-frame{width:100%;border:0;min-height:680px;display:block}.lab-board{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.layer{border:1px solid var(--line);background:var(--panel2);border-radius:13px;padding:12px 17px;margin-bottom:8px;display:flex;align-items:center;justify-content:space-between;gap:10px}.layer.active{border-color:var(--accent-text);color:var(--accent-text)}.layer button{border:1px solid var(--line);border-radius:8px;background:var(--panel);min-height:40px;min-width:40px}.packet{padding:18px;border:2px solid var(--blue);border-radius:14px;background:var(--panel2);margin:12px 0;text-align:center}.packet .packet{background:var(--bg)}.download-row{display:flex;justify-content:space-between;align-items:center;gap:15px;flex-wrap:wrap;padding:18px 0;border-bottom:1px solid var(--line)}.download-row:last-child{border:0}.download-row p{font-size:13px;color:var(--muted)}.timer-big{font:700 52px/1.3 Arial;direction:ltr;text-align:center;color:var(--accent-text);margin:20px 0}.split-line{border:0;border-top:1px solid var(--line);margin:25px 0}.sticky-action{margin-top:22px}.sr{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);border:0}.skip{position:absolute;top:-100px;z-index:100;background:var(--action);color:var(--ink);padding:12px}.skip:focus{top:0}#nav{position:fixed;bottom:0;inset-inline:0;z-index:20;display:flex;justify-content:center;gap:4px;background:var(--bg);border-top:1px solid var(--line);padding:8px 12px calc(8px + env(safe-area-inset-bottom));box-shadow:0 -8px 32px #0001}#nav a{display:flex;flex-direction:column;align-items:center;text-decoration:none;font-size:12px;min-width:90px;padding:5px 12px;border-radius:12px;color:var(--muted);line-height:1.5}#nav a span{font-size:22px;line-height:1.4}#nav a.active{color:var(--accent-text);background:var(--panel2)}#toast{position:fixed;bottom:105px;left:50%;transform:translate(-50%,20px);background:var(--action);color:var(--ink);padding:12px 20px;border-radius:14px;z-index:100;opacity:0;pointer-events:none;transition:.2s;max-width:90%;text-align:center;font-size:14px}#toast.show{opacity:1;transform:translate(-50%,0)}dialog{background:var(--panel);color:var(--text);border:1px solid var(--line);border-radius:22px;width:min(600px,94vw);max-height:85dvh;padding:27px}dialog::backdrop{background:#0009}dialog form{margin-top:20px}#update-banner{background:var(--blue);color:var(--ink);padding:12px;text-align:center;font-size:14px}#update-banner button{margin-inline-start:12px;color:var(--ink);border-color:var(--ink)}.attention{color:var(--wrong)}.bookmarked{color:var(--accent-text)}.details-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}.footer-note{font-size:12px;color:var(--muted);margin-top:28px;text-align:center}.lesson-content img{max-width:100%;height:auto}.result-topic{display:flex;justify-content:space-between;gap:15px;border-bottom:1px solid var(--line);padding:12px 0}.source-figure{margin:20px 0}.source-figure a{display:block}.source-figure img{width:100%;background:white;border-radius:12px}.source-figure figcaption{font-size:12px;color:var(--muted);margin-top:8px}
@media(min-width:1400px){main,.top-inner{max-width:1260px}.scope-inner{max-width:1204px}}@media(max-width:900px){.hero{grid-template-columns:1fr 1fr;gap:24px}.hero-visual{padding:19px}.lesson-layout{grid-template-columns:1fr}.lesson-aside{display:none}.lesson-picker{display:block;margin-bottom:15px;width:100%}.grid.three{grid-template-columns:repeat(2,minmax(0,1fr))}.scope-inner{padding-inline:28px}}@media(max-width:620px){body{font-size:15px}.top-inner{padding:13px 17px}.brand{font-size:23px;gap:9px}.brand small{font-size:7px;letter-spacing:1px}.mark{width:41px;height:41px;border-radius:12px;font-size:27px}.top .row{gap:6px}.top select{padding:7px;font-size:14px;min-height:42px}.icon-btn{width:40px;height:42px;font-size:22px}.scope-inner{padding:9px 17px;font-size:12px}.scope-inner .scope-text{max-width:67%;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}main{padding:23px 17px 35px}.hero{grid-template-columns:1fr;margin-bottom:20px;padding-top:7px;gap:21px}.hero h1{font-size:35px}.hero-visual{transform:none;padding:13px 20px}.hero-visual .phase{padding:8px 0}.hero-visual .phase b{font-size:23px}.hero-visual .phase .en{display:none}.hero p{font-size:15px;margin:14px 0 20px}.hero-visual .kicker{display:none}.hero .row .btn{flex:1;padding-inline:10px}.grid,.grid.three,.fields,.fields.two,.lab-board,.details-grid{grid-template-columns:1fr}.card{padding:20px;border-radius:19px}.stats{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.stat{padding:13px 15px}.stat strong{font-size:27px}.quick-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.quick{padding:17px;min-height:103px}.scope-items{grid-template-columns:1fr}.scope-summary{padding:13px;bottom:85px}.scope-summary .row{justify-content:space-between}.scope-summary .btn{padding:10px}.question-card h2{font-size:21px}.option{padding:13px 11px;gap:10px}.flash{min-height:330px}.flash h2{font-size:22px}.flash-actions .btn{flex:1;padding-inline:8px;font-size:13px}.course .course-top{margin-bottom:15px}.course-badge{font-size:12px;padding:13px}.btn{padding:11px 15px}#nav{gap:0;padding-inline:7px}#nav a{min-width:0;flex:1;max-width:100px;font-size:11px;padding:5px 3px}h2{font-size:22px}.section-title{margin-top:24px}.layer{padding:10px;font-size:14px}.layer .row{gap:5px}.scope-inner button{font-size:12px}.table-scroll{margin-inline:-5px;width:calc(100% + 10px)}.download-row .row{width:100%}.download-row .btn{flex:1}.source-figure{margin-inline:0}.result-topic{font-size:13px}.hero .label{font-size:10px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}@media print{.top,#nav,#scope-bar,.skip{display:none}body{background:white;color:black;padding:0}main{padding:0}.card{box-shadow:none;border:0}}

/* ZeroDigit website color roles, adapted to Thabbit controls. */
html{color-scheme:dark}html[data-theme=light]{color-scheme:light}
h1,h2,h3,.brand{color:var(--heading)}
.top{background:var(--nav-bg)}
.hero-visual{background:linear-gradient(135deg,var(--hero-a),var(--hero-b) 58%,var(--hero-c))}
.btn.blue,.course.blue .course-badge{background:var(--secondary-fill);color:var(--secondary-ink)}
.option.correct{border-color:var(--good)}