:root{color-scheme:light;--navy:#0b1930;--navy2:#122541;--ink:#15263c;--muted:#567087;--teal:#006b68;--mint:#a4edda;--gold:#fbd77b;--paper:#f4f8fb;--white:#fff;--line:#dce7ee;--light:#e5f5f2;--error:#a13733;font:16px/1.65 system-ui,-apple-system,"Segoe UI",sans-serif}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);background:var(--paper)}a{color:var(--teal);text-decoration:none}a:hover{text-decoration:underline}a:focus-visible,button:focus-visible,textarea:focus-visible,input:focus-visible{outline:3px solid #ffbd2e;outline-offset:3px}button,input,textarea{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.52}img{max-width:100%}
header{position:sticky;top:0;z-index:25;background:#0b1930f7;border-bottom:1px solid #294564;color:#fff;backdrop-filter:blur(16px)}.site-nav{max-width:1190px;margin:auto;padding:12px 22px;display:flex;justify-content:space-between;align-items:center;gap:16px;flex-wrap:wrap}.brand{display:flex;align-items:center;gap:9px;color:white;font-weight:900;letter-spacing:-.035em;font-size:19px}.brand-mark{display:inline-grid;place-items:center;width:32px;height:32px;border-radius:10px;background:var(--gold);color:var(--navy)}.nav-links{display:flex;align-items:center;gap:5px;flex-wrap:wrap;font-size:13px;font-weight:750}.nav-links a{color:#e4f2f9;padding:8px 11px;border-radius:10px}.nav-links a:hover{background:#233d59;text-decoration:none}.nav-links .nav-accent{background:var(--gold);color:#20283a}
.wrap{max-width:1190px;margin:auto;padding:28px 22px 78px}.eyebrow{display:inline-flex;gap:6px;align-items:center;text-transform:uppercase;letter-spacing:.09em;font-size:12px;font-weight:850;color:var(--teal)}h1,h2,h3{letter-spacing:-.03em;line-height:1.2}h1{font-size:clamp(32px,5.2vw,58px);margin:12px 0 18px}h2{font-size:clamp(24px,3.3vw,35px);margin:0 0 12px}h3{font-size:clamp(19px,2.2vw,24px);margin:0 0 9px}p{margin:10px 0;line-height:1.76}.lead{font-size:clamp(17px,2vw,21px);line-height:1.7;color:#c9ddea;max-width:650px}.muted{color:var(--muted)}.subtle{font-size:14px;color:var(--muted)}.tiny{font-size:12px}.space-top{margin-top:30px}.section-heading{display:flex;align-items:end;justify-content:space-between;gap:12px;flex-wrap:wrap;margin:35px 0 16px}.section-heading p{max-width:690px;color:var(--muted)}
.hero{overflow:hidden;border-radius:27px;background:radial-gradient(circle at 82% 25%,#275773 0%,transparent 46%),linear-gradient(122deg,#08182d,#142943 85%);color:white;padding:clamp(22px,4.5vw,57px);border:1px solid #41617b;display:grid;grid-template-columns:1.2fr .8fr;gap:24px;align-items:center}.hero .eyebrow{color:#96f0d1}.hero h1{max-width:780px}.hero-copy{max-width:690px}.highlight{color:var(--gold)}.hero-art{position:relative;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));align-items:end;gap:5px}.hero-art>div{text-align:center;background:#ffffff15;border:1px solid #ffffff2b;border-radius:16px;padding:8px 3px}.hero-art img{width:100%;height:210px;object-fit:contain;filter:drop-shadow(0 14px 9px #0005)}.hero-art b{font-size:13px;display:block}.hero-art small{font-size:11px;color:#d8ecee}
.actions{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin:18px 0}.btn,button.primary,button.secondary,button.ghost{border:0;border-radius:12px;padding:13px 18px;display:inline-flex;justify-content:center;align-items:center;gap:8px;font-weight:800;min-height:46px;font-size:15px;text-align:center;text-decoration:none}.btn:hover,button.primary:hover{text-decoration:none;filter:brightness(.95)}.btn,button.primary{background:var(--gold);color:#13253c}.btn.dark{background:var(--navy);color:white}.btn.light{background:#e1f2ef;color:#075855}.btn.outline,button.secondary{background:#fff;color:#145b61;border:1px solid #bfd2d8}.btn.glass{background:#ffffff20;color:#fff;border:1px solid #ffffff4a}button.ghost{background:transparent;color:var(--teal);border:1px solid var(--line)}
.panel{background:white;padding:clamp(18px,3vw,27px);border-radius:22px;border:1px solid var(--line);margin:17px 0;box-shadow:0 11px 28px #0f29430b}.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:17px}.course-card{display:flex;flex-direction:column;border:1px solid var(--line);background:#fff;border-radius:18px;overflow:hidden;color:var(--ink);transition:transform .18s ease,box-shadow .18s ease}.course-card:hover{transform:translateY(-3px);box-shadow:0 16px 24px #091e3220;text-decoration:none}.course-card img{height:176px;width:100%;object-fit:cover;background:#d6e9f0}.course-card .content{padding:17px 18px;display:flex;flex-direction:column;gap:7px;flex:1}.course-card h3{margin:0;font-size:20px}.course-card p{margin:0;color:var(--muted);font-size:14px}.course-card .bottom{margin-top:auto;padding-top:10px;color:var(--teal);font-weight:850}.pill{display:inline-block;padding:5px 11px;border-radius:999px;background:var(--light);color:var(--teal);font-size:12px;font-weight:850}.pill.gold{background:#fff1bf;color:#725205}.course-top{display:flex;justify-content:space-between;gap:6px;align-items:center}.step-strip{display:grid;grid-template-columns:repeat(4,1fr);gap:13px}.step-card{padding:17px;border-radius:16px;background:#fff;border:1px solid var(--line)}.step-card b{display:block;margin-top:8px}.step-card span{display:block;color:var(--muted);font-size:13px}.step-num{width:32px;height:32px;border-radius:10px;background:var(--light);color:var(--teal);display:grid;place-items:center;font-weight:950}.teachers{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.teacher{border:1px solid var(--line);background:linear-gradient(135deg,#f1f8fb,#d9eeeb);border-radius:18px;padding:14px;text-align:center}.teacher img{height:160px;width:100%;object-fit:contain}.teacher b{display:block}.teacher small{color:var(--muted)}
.study-shell{display:grid;grid-template-columns:minmax(0,1fr) 290px;align-items:start;gap:23px}.study-main{min-width:0}.study-aside{position:sticky;top:92px}.study-aside .panel{margin-top:0}.study-header{background:linear-gradient(120deg,#0a1d36,#1a4c5c);padding:clamp(18px,3.2vw,31px);border-radius:20px;color:white;margin:16px 0}.study-header h1{font-size:clamp(29px,3.7vw,42px);margin:11px 0}.study-header p{color:#d8e8ed}.crumb{font-size:14px;color:var(--muted);margin:6px 0 10px}.crumb a{font-weight:700}.meter{height:10px;background:#d9e8ee;border-radius:100px;overflow:hidden;margin-top:16px}.meter i{display:block;background:linear-gradient(90deg,#2bc7b8,#81dfbf);height:100%;width:0;transition:width .25s ease}.study-header .meter{background:#ffffff30}.study-header .meter i{background:var(--gold)}.teacher-inline{display:flex;align-items:center;gap:13px;padding:9px;background:#ecf8f5;border-radius:16px;border:1px solid #d8ece7;margin-bottom:22px}.teacher-inline img{width:93px;height:95px;object-fit:contain}.teacher-inline b{display:block}.teacher-inline span{color:#4b7978;font-size:13px}.paragraphs{font-size:17px;line-height:1.88}.paragraphs p{margin:13px 0 18px}.concept{border-left:4px solid #12aa9b;padding:15px 18px;background:#e9f8f3;border-radius:10px;margin:21px 0}.concept p{margin:7px 0}.section-divider{height:1px;background:var(--line);margin:28px 0}.case-visual{display:grid;grid-template-columns:240px minmax(0,1fr);gap:20px;align-items:center;background:#f1f8fb;border:1px solid #d9e8ed;border-radius:18px;overflow:hidden;margin:18px 0}.case-visual img{width:100%;height:200px;object-fit:cover}.case-visual>div{padding:17px 18px 17px 0}.case-visual p{font-size:15px;margin:8px 0}.flow-diagram{display:flex;align-items:stretch;justify-content:space-between;gap:8px;margin:18px 0;flex-wrap:wrap}.flow-diagram .flow-block{background:#ebf6f4;border:1px solid #c3e3df;border-radius:13px;padding:15px;flex:1;min-width:125px}.flow-block b{display:block;color:#076960;font-size:13px}.flow-block span{font-size:13px;color:#315f61}.flow-arrow{align-self:center;color:#428b8a;font-size:21px;font-weight:900}.compare{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:13px 0}.compare>div{padding:17px;border-radius:14px;border:1px solid #e8d5d0;background:#fff7f4;font-size:14px;white-space:pre-wrap;overflow-wrap:anywhere}.compare>div.good{border-color:#abd9ca;background:#effaf5}.compare strong{display:block;margin-bottom:8px}.task-box{background:#f2f7fc;border-radius:16px;padding:20px;border:1px solid var(--line)}.task-box textarea{width:100%;min-height:150px;resize:vertical;margin-top:12px;line-height:1.7;padding:15px;border:1px solid #aebfca;border-radius:12px;background:white;color:var(--ink)}.task-box label{font-weight:800}.feedback{padding:12px;border-radius:10px;margin-top:12px;background:#eaf1f5;font-size:14px;color:#38556b}.feedback.ok{background:#e5f6ea;color:#18643a}.feedback.warn{background:#fff2d9;color:#66400f}.quiz{background:#f8fafb;border:1px solid var(--line);border-radius:16px;padding:20px}.quiz-option{width:100%;display:block;padding:12px 15px;text-align:left;background:white;border:1px solid #c8d9df;border-radius:11px;margin:9px 0;color:var(--ink)}.quiz-option:hover{border-color:#1e9c92}.quiz-option.selected{border:2px solid #0b8075;background:#e8f8f4}.lesson-navigation{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;margin:20px 0}.sidebar-stages{display:grid;gap:7px}.sidebar-stages a{padding:10px 12px;background:#f2f7f8;color:#365367;border:1px solid #e2eef0;border-radius:10px;font-size:13px;line-height:1.3;display:flex;gap:9px;align-items:center}.sidebar-stages a:hover{text-decoration:none;background:#e7f3f0}.sidebar-stages .active{font-weight:850;border-color:#52b2a9;background:#e5f8f3;color:#0b625b}.sidebar-stages .done::after{content:'✓';color:#0c8669;margin-left:auto;font-weight:900}.sidebar-stages .locked{opacity:.8}.sidebar-stages .num{font-weight:850}.prompt-output{white-space:pre-wrap;overflow-wrap:anywhere;background:#0e213a;border-radius:14px;padding:20px;color:#e9f6ee;font:14px/1.7 ui-monospace,SFMono-Regular,Consolas,monospace;max-height:500px;overflow:auto}.hidden{display:none!important}.lock-view{border:2px dashed #9bb8bd;background:#f0f7f7;border-radius:15px;padding:25px}.auth-card{max-width:630px;margin:38px auto}.auth-card input{width:100%;border:1px solid #a9bdca;border-radius:12px;padding:12px 14px;margin-top:6px}.auth-card label{font-weight:750;display:block;margin:17px 0}.input-message{padding:12px;background:#eef7f4;border-radius:10px}.progress-row{display:flex;align-items:center;justify-content:space-between;gap:15px}.result-tag{font-weight:750;color:#136d62}.footer{border-top:1px solid #d8e5eb;text-align:center;color:#567087;padding:27px 20px;font-size:13px}.callout{background:#122743;color:#e7f6f4;border-radius:18px;padding:22px 27px}.callout h3{color:white}.fineprint{font-size:12px;color:#708494}.progress-cards{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.progress-card{display:flex;gap:15px;background:white;border:1px solid var(--line);border-radius:16px;padding:14px;align-items:center;color:var(--ink)}.progress-card img{height:86px;width:110px;object-fit:cover;border-radius:10px}.progress-card p{margin:3px 0;font-size:13px;color:var(--muted)}.progress-card strong{display:block}
@media(max-width:970px){.hero{grid-template-columns:1fr}.hero-art img{height:155px}.grid{grid-template-columns:repeat(2,1fr)}.study-shell{grid-template-columns:minmax(0,1fr) 245px}.case-visual{grid-template-columns:185px 1fr}.step-strip{grid-template-columns:repeat(2,1fr)}}
@media(max-width:740px){.site-nav{padding:9px 14px}.nav-links{gap:1px}.nav-links a{font-size:12px;padding:7px}.wrap{padding:17px 14px 55px}.study-shell{grid-template-columns:1fr}.study-aside{position:static;order:2}.study-main{order:1}.grid,.progress-cards{grid-template-columns:1fr}.hero{padding:24px}.hero-art img{height:120px}.hero-art b{font-size:11px}.hero-art small{font-size:10px}.compare{grid-template-columns:1fr}.case-visual{grid-template-columns:1fr}.case-visual img{height:210px}.case-visual>div{padding:5px 17px 17px}.teachers img{height:110px}.teacher{padding:8px}.teacher b{font-size:13px}.teacher small{font-size:11px}.flow-diagram{flex-direction:column}.flow-arrow{transform:rotate(90deg)}.lesson-navigation a{flex:1}.study-header{padding:22px 18px}.paragraphs{font-size:16px}.progress-card img{width:95px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}

@media(max-width:580px){.panel[style*="grid-template-columns"]{grid-template-columns:1fr!important}}

.rubric{display:grid;gap:9px;margin:12px 0 20px}.rubric label{display:flex;align-items:flex-start;gap:12px;padding:12px 14px;border:1px solid #d4e6de;background:#f3faf7;border-radius:11px;cursor:pointer;font-size:14px}.rubric input{accent-color:#0b8279;min-width:18px;width:18px;height:18px;margin:3px 0 0;flex-shrink:0}.rubric label:has(input:checked){border-color:#5aad99;background:#e6f7ed}