:root{--ink:#162f3b;--muted:#536975;--green:#16665d;--pale:#e9f4ef;--blue:#305fb0;--line:#dce5e5;--paper:#fff;--bg:#f5f8f7;--orange:#ac590b;font-family:Inter,system-ui,-apple-system,Segoe UI,sans-serif;color:var(--ink);background:var(--bg);font-size:17px;line-height:1.65}*{box-sizing:border-box}body{margin:0}a{color:var(--green);text-underline-offset:.2em}button,input,select{font:inherit}button,a,input,select{touch-action:manipulation}button{cursor:pointer}button:disabled{cursor:default;opacity:.5}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,[tabindex]:focus-visible{outline:3px solid #c5771b;outline-offset:4px}h1,h2,h3,p{margin-top:0}h1,h2,h3{line-height:1.18;letter-spacing:-.035em}h1{font-size:clamp(2rem,4.5vw,3.8rem);max-width:1000px}h2{font-size:1.7rem}h3{font-size:1.12rem}p:last-child{margin-bottom:0}h1:focus{outline:none}.skip{position:absolute;top:-100px}.skip:focus{top:0;background:white;z-index:100;padding:12px}.site-header{max-width:1260px;margin:auto;padding:24px 28px;display:flex;justify-content:space-between;gap:20px;border-bottom:1px solid var(--line);align-items:center}.brand{display:flex;gap:12px;align-items:center;text-decoration:none;color:var(--ink);font-weight:750;font-size:1.2rem}.brand small{display:block;font-size:.7rem;font-weight:500;color:var(--muted);letter-spacing:.01em}.mark{background:var(--green);color:#fff;border-radius:13px;padding:0 12px;font-family:Georgia;font-size:1.8rem}nav{display:flex;gap:24px;flex-wrap:wrap}nav a{text-decoration:none;font-size:.9rem}main{max-width:1204px;margin:0 auto;padding:44px 24px 70px;min-width:0}.hero{display:grid;grid-template-columns:1.3fr .8fr;align-items:center;gap:40px;padding:25px 0 50px}.hero h1 em{font-family:Georgia,serif;font-weight:normal;color:var(--green)}.hero-art svg{width:100%;max-height:330px}.eyebrow{font-size:.7rem;font-weight:750;letter-spacing:.16em;text-transform:uppercase;color:var(--green);margin-bottom:14px}.lead{font-size:1.13rem;color:var(--muted);line-height:1.6}.actions{display:flex;flex-wrap:wrap;gap:10px;margin:22px 0}.button{display:inline-flex;justify-content:center;align-items:center;gap:8px;min-height:46px;padding:11px 19px;border:1px solid var(--green);background:var(--green);color:white;border-radius:12px;text-decoration:none;font-size:.92rem;font-weight:650;line-height:1.3}.quiet{background:white;color:var(--green);border-color:var(--line)}.small{font-size:.82rem}.muted{color:var(--muted)}.how{display:flex;justify-content:space-between;gap:20px;border-block:1px solid var(--line);padding:20px 0;margin-bottom:44px}.how b{color:var(--green);margin-right:10px}.section-head{display:flex;gap:20px;align-items:center;margin:42px 0 20px}.section-head .num{font:italic 2.9rem Georgia;color:#91afa4}.section-head h2{margin:0 0 5px}.section-head p{font-size:.9rem;color:var(--muted)}.lesson-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px}.lesson-card{display:flex;flex-direction:column;padding:22px;border-radius:17px;border:1px solid var(--line);background:white;text-decoration:none;color:var(--ink)}.lesson-card:hover{border-color:#7daaa0;box-shadow:0 4px 18px #164b3710}.lesson-card p{font-size:.86rem;color:var(--muted)}.lesson-card .status{font-size:.75rem;color:var(--green);margin-top:auto;padding-top:15px}.panel{background:var(--paper);border:1px solid var(--line);border-radius:20px;padding:27px;min-width:0}.note,.takeaway{background:var(--pale);border-left:4px solid var(--green);padding:17px 21px;border-radius:0 12px 12px 0;margin:22px 0}.warning{max-width:1140px;margin:20px auto;padding:16px;background:#fff4d9;color:#77410c;border-radius:12px}.lesson-layout{display:grid;grid-template-columns:minmax(0,1fr) 285px;gap:24px;align-items:start}.lesson-layout .panel+.panel{margin-top:24px}.lesson-layout aside{position:sticky;top:20px}.theory{font-size:1rem}.theory h3{margin:27px 0 12px}.theory table{border-collapse:collapse;width:100%;font-size:.87rem}.theory td,.theory th{border:1px solid var(--line);padding:8px;text-align:left}.breadcrumb{font-size:.8rem;color:var(--muted);margin-bottom:24px}.breadcrumb span{margin:0 10px}.task-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin-top:20px}.task-card{padding:16px;border:1px solid var(--line);border-radius:12px;background:white;min-width:0}.task-card h3{margin:0 0 9px;letter-spacing:0}.task-card .actions{margin:12px 0 0}.task-card .button{font-size:.78rem;padding:8px 12px}.task-card .task-preview{font-size:.85rem;color:var(--muted)}.task-card .status{font-size:.72rem;color:var(--green)}.practice-head{display:flex;gap:25px;align-items:start;justify-content:space-between}.practice-head h1{font-size:clamp(1.8rem,3.3vw,2.8rem)}.practice-layout{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,.95fr);gap:22px;align-items:start}.task-condition{font-size:1.16rem;margin-bottom:20px}.task-condition sup,.task-preview sup{font-size:.73em}.steps{display:flex;flex-wrap:wrap;gap:7px;list-style:none;padding:0;margin:24px 0}.steps li{width:32px;height:32px;display:grid;place-items:center;border-radius:50%;background:#edf0f0;color:var(--muted);font-size:.8rem}.steps .current{background:var(--green);color:white}.steps .passed{background:#d9eee4;color:#16654e}.question{margin:22px 0 18px;font-weight:650}.answer-field{margin:20px 0;padding:0;border:0;min-width:0}.answer-field legend,.answer-field>label{font-size:.9rem;font-weight:600;margin-bottom:9px;display:block;max-width:100%}.answer-field input[type=text]{display:block;width:100%;max-width:400px;min-width:0;border:1px solid #a4b6b7;border-radius:10px;padding:12px;margin-top:9px;background:#fcfdfd;color:var(--ink)}.choices{display:grid;gap:8px}.choice{display:flex;align-items:flex-start;gap:10px;border:1px solid var(--line);border-radius:11px;padding:11px 13px;min-width:0;font-size:.95rem;background:#fcfdfd}.choice:has(input:checked){border-color:var(--green);background:var(--pale)}.choice input{margin-top:7px;flex:0 0 auto;width:17px;height:17px;accent-color:var(--green)}.choice span{min-width:0;overflow-wrap:anywhere}.order-pool{display:flex;flex-wrap:wrap;gap:8px}.order-item{border:1px solid var(--line);background:white;color:var(--ink);border-radius:8px;padding:9px 12px;min-height:44px}.order-selected{padding:12px;background:var(--pale);border-radius:12px;display:flex;flex-wrap:wrap;gap:8px;min-height:52px;margin:10px 0}.feedback{margin:18px 0 12px;min-height:28px;font-size:.95rem}.feedback.good{padding:14px;background:var(--pale);border-radius:12px;color:#155743}.feedback.bad{padding:14px;background:#fff2e5;border-radius:12px;color:#874000}.hint-box{background:#fff5e4;border-radius:12px;padding:18px;margin:15px 0}.lab-note{font-size:.79rem;color:var(--muted)}.result-symbol{display:grid;place-items:center;background:var(--pale);color:var(--green);width:58px;height:58px;border-radius:50%;font-size:2rem;margin-bottom:22px}.result-panel{max-width:920px}.solution{border-top:1px solid var(--line);padding-top:25px;margin-top:25px}.solution li{margin:10px 0}.solution-list{padding-left:22px}.progress-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}progress{width:100%;height:10px;accent-color:var(--green)}.jump-form{display:flex;align-items:end;gap:10px;flex-wrap:wrap;margin:25px 0}.jump-form label{font-size:.82rem}.jump-form input{display:block;padding:10px;border-radius:10px;border:1px solid #a4b6b7;width:150px;min-width:0}.point-note{padding:12px;border:1px dashed #93b6b0;border-radius:10px;font-size:.86rem}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}footer{max-width:1160px;margin:auto;border-top:1px solid var(--line);padding:25px 24px 45px;color:var(--muted);font-size:.76rem}.back-top{margin:35px 0}img,svg{max-width:100%}main p,main h1,main h2,main h3,main a,main label{overflow-wrap:anywhere}input[type=range]{min-width:0;max-width:100%}@media(max-width:980px){.lesson-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.lesson-layout{grid-template-columns:minmax(0,1fr)}.lesson-layout aside{position:static;display:grid;grid-template-columns:1fr 1fr;gap:15px}.lesson-layout aside .panel{margin:0}.practice-layout{grid-template-columns:minmax(0,1fr)}.practice-lab{order:-1}.hero{gap:15px}}@media(max-width:600px){:root{font-size:16px}.site-header{padding:17px 18px;flex-wrap:wrap;gap:15px}nav{gap:19px;width:100%;font-size:.84rem}main{padding:27px 16px 45px}.hero{grid-template-columns:1fr;padding:10px 0 25px}.hero-art{display:none}.hero h1{font-size:2.45rem}.how{flex-direction:column;gap:8px;font-size:.88rem;padding:16px 0;margin-bottom:25px}.lesson-grid,.task-list,.progress-grid{grid-template-columns:1fr}.panel{padding:20px;border-radius:15px}.lesson-layout aside{display:block}.lesson-layout aside .panel+.panel{margin-top:15px}.practice-head{display:block}.practice-head>a{display:inline-block;margin-bottom:15px}.section-head{gap:12px}.section-head .num{font-size:2.2rem}.section-head h2{font-size:1.5rem}.button{max-width:100%}.answer-field input[type=text]{font-size:1rem}.theory table{font-size:.72rem}.theory td,.theory th{padding:5px}.task-condition{font-size:1.05rem}.actions{gap:8px}.choice{padding:10px}.point-note{font-size:.8rem}}@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;animation:none!important;transition:none!important}}
/* The brand must reflow even on a 360 px screen at 200% zoom. */
.brand{min-width:0;max-width:100%}.brand>span:last-child{min-width:0;overflow-wrap:anywhere}.brand .mark{flex-shrink:0}.jump-form label{min-width:0;max-width:100%}.jump-form input{max-width:100%}
.site-header nav{flex-wrap:wrap}