:root{--ink:#172a25;--forest:#215941;--forest-dark:#153e2e;--mint:#def3e8;--paper:#f5f6f0;--line:#dce5dd;--muted:#5e7068}
*{box-sizing:border-box}
body{margin:0;background:var(--paper);color:var(--ink);font-family:"PingFang SC","Microsoft YaHei",sans-serif;line-height:1.65}
a{color:var(--forest)}
button,select{font:inherit}
button{cursor:pointer}
[hidden]{display:none!important}
:focus-visible{outline:3px solid #176f51;outline-offset:3px}
.skip{position:absolute;left:-9999px;top:6px;z-index:100;background:#fff;padding:8px 12px}
.skip:focus{left:8px}
.topbar{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:15px;max-width:980px;margin:auto;padding:20px 24px}
.topbar .brand{font-weight:800;font-size:19px;text-decoration:none}
.topbar nav{display:flex;flex-wrap:wrap;gap:8px 20px;font-size:14px}
.topbar nav a{text-decoration:none}
.shell{max-width:980px;margin:auto;padding:0 24px 70px}
.hero{padding:66px 60px;border-radius:25px;background:linear-gradient(135deg,#163e35,#236c52);color:#fff}
.eyebrow{font-size:12px;font-weight:800;letter-spacing:.12em;margin:0 0 10px;color:#6bb88e}
.hero .eyebrow,.lesson-hero .eyebrow{color:#b9eaca}
.hero h1{font-size:clamp(32px,5vw,52px);line-height:1.23;margin:0 0 20px}
.hero>p:last-child{max-width:510px;margin:0;color:#e3f0e8}
.intro{display:grid;grid-template-columns:repeat(3,1fr);gap:13px;margin:18px 0 52px}
.intro div{display:flex;gap:12px;align-items:center;background:#fff;border:1px solid var(--line);border-radius:13px;padding:16px;font-size:13px}
.intro strong{font-size:20px;color:var(--forest)}
.heading h2{font-size:26px;margin:0 0 22px}
.cards{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}
.lesson-card{display:block;padding:28px;background:#fff;border:1px solid var(--line);border-radius:19px;text-decoration:none;color:var(--ink);box-shadow:0 3px 16px rgba(20,60,40,.04)}
.lesson-card:hover{box-shadow:0 9px 24px rgba(20,60,40,.12);transform:translateY(-2px)}
.lesson-card .audience{display:inline-block;color:var(--forest);font-size:12px;font-weight:800}
.lesson-card h2{font-size:23px;margin:12px 0 8px}
.lesson-card p{font-size:14px;color:var(--muted);margin:0 0 26px}
.lesson-card .status{font-size:14px;font-weight:800;color:var(--forest)}
.note{font-size:13px;color:var(--muted);margin:23px 0}
footer{text-align:center;border-top:1px solid var(--line);padding:30px 16px;color:var(--muted);font-size:12px}
.back{display:inline-block;margin:6px 0 18px;text-decoration:none;font-size:14px}
.lesson-hero{padding:38px 42px;border-radius:21px;background:linear-gradient(135deg,#163e35,#236c52);color:#fff}
.lesson-hero h1{margin:0 0 11px;font-size:35px}
.lesson-hero>p:not(.eyebrow){margin:0;color:#e3f0e8}
.goal{display:flex;gap:12px;align-items:center;flex-wrap:wrap;margin-top:22px;padding-top:20px;border-top:1px solid rgba(255,255,255,.23);font-size:14px}
.goal strong{color:#b9eaca}
.player-card,.quiz-card{background:#fff;border:1px solid var(--line);border-radius:19px;padding:28px;margin-top:18px}
.player-card .heading h2,.quiz-card .heading h2{margin-bottom:16px}
.controls,.settings{display:flex;gap:9px;align-items:center;flex-wrap:wrap}
.controls button,.understood button,.submit{border:0;background:var(--forest);color:#fff;border-radius:999px;padding:10px 18px;font-weight:700;min-height:44px}
.controls button:not(:first-child){background:#eaf4ed;color:var(--forest-dark)}
.controls button:hover,.understood button:hover,.submit:hover{filter:brightness(.92)}
.settings{margin:16px 0;font-size:13px;color:var(--muted);gap:8px 17px}
.settings label{display:inline-flex;align-items:center;gap:5px}
.settings input{accent-color:var(--forest)}
.settings select{border:1px solid var(--line);padding:5px;border-radius:7px;background:#fff;min-height:44px}
.audio-status{font-size:13px;color:var(--forest-dark);background:#edf7f0;border-radius:8px;padding:9px 12px}
.voice-fallback{margin:12px 0;padding:14px;border:1px solid #b4d5c0;border-radius:10px;background:#f3faf5;font-size:14px}
.voice-fallback>label{display:block;font-weight:700}
.voice-fallback>div{display:flex;flex-wrap:wrap;gap:9px;margin-top:10px}
.voice-fallback select{min-width:0;max-width:100%;min-height:44px;padding:7px;border:1px solid var(--line);border-radius:8px;background:#fff}
.voice-fallback button{min-height:44px;padding:7px 14px;border:0;border-radius:8px;background:var(--forest);color:#fff;font-weight:700}
.voice-fallback p{margin:9px 0 0;color:var(--muted);font-size:12px}
.lines{padding:0;margin:20px 0;list-style:none;display:grid;gap:8px}
.line{display:grid;grid-template-columns:90px minmax(0,1fr) auto;gap:12px;align-items:center;padding:13px 15px;border:1px solid var(--line);border-radius:11px;scroll-margin-top:20px}
.line.is-playing{background:#e4f6e9;border-color:#41a675;box-shadow:inset 3px 0 #268b62}
.speaker{font-weight:800;color:var(--forest-dark);font-size:13px;overflow-wrap:anywhere}
.line-copy{display:grid;gap:4px;min-width:0}
.english{font-size:15px;font-weight:700;overflow-wrap:anywhere}
.translation{font-size:12px;color:var(--muted)}
.hide-english .english,.hide-translation .translation{display:none}
.line-play{border:0;background:#eaf4ed;color:var(--forest-dark);border-radius:50%;width:44px;height:44px}
.understood{display:flex;align-items:center;gap:12px;flex-wrap:wrap;padding-top:14px;border-top:1px solid var(--line);font-size:13px;color:var(--forest)}
.quiz-card>p{font-size:14px;color:var(--muted);margin:0 0 18px}
.question{border:1px solid var(--line);border-radius:12px;margin:0 0 14px;padding:14px}
.question legend{font-weight:700;padding:0 5px}
.answers{display:flex;flex-wrap:wrap;gap:8px;margin-top:6px}
.answers label{display:inline-flex;align-items:center;gap:6px;background:#eff7f0;border-radius:9px;padding:8px 12px;cursor:pointer}
.answers input{accent-color:var(--forest)}
.answers label:focus-within{outline:3px solid #176f51;outline-offset:2px}
.question.is-correct{border-color:#279866}.question.is-incorrect{border-color:#cd704b}
.feedback{font-size:13px;margin:10px 0 0;color:var(--forest-dark)}
.quiz-result{font-size:14px;color:var(--forest-dark)}
@media(max-width:650px){.topbar,.shell{padding-left:15px;padding-right:15px}.topbar nav{gap:9px;font-size:12px}.hero{padding:43px 25px}.intro,.cards{grid-template-columns:1fr}.intro{margin-bottom:35px}.lesson-hero{padding:32px 22px}.lesson-hero h1{font-size:29px}.player-card,.quiz-card{padding:19px}.line{grid-template-columns:54px minmax(0,1fr) auto;gap:7px;padding:11px 9px}.english{font-size:14px}.answers{flex-direction:column}}