:root{--green:#163c34;--accent:#b8e3b6;--ink:#1d302b;--muted:#718079;--line:#dde5df;--bg:#f4f6f2}*{box-sizing:border-box}body{margin:0;background:var(--bg);font:16px/1.65 -apple-system,BlinkMacSystemFont,'PingFang SC','Microsoft YaHei',sans-serif;color:var(--ink)}header{max-width:1100px;margin:auto;padding:26px 30px;display:flex;align-items:center;justify-content:space-between}.brand{display:flex;gap:12px;align-items:center;text-decoration:none;color:var(--ink);font-weight:700;font-size:20px}.brand small{display:block;font-size:9px;letter-spacing:2px;color:var(--muted)}.logo{background:var(--green);color:white;border-radius:12px;width:45px;height:45px;text-align:center;font-size:28px}.tag{font-size:13px;color:var(--muted)}main{max-width:1040px;margin:24px auto 60px;padding:0 24px}h1{font-size:40px;line-height:1.3;letter-spacing:-1px;margin:12px 0 20px}h2{font-size:23px;line-height:1.6;margin:12px 0 24px}h3{margin:0;font-size:21px}p{margin:8px 0}.eyebrow{font-size:12px;letter-spacing:2px;color:var(--muted)}.hero{padding:42px;background:var(--green);color:white;border-radius:24px;position:relative;overflow:hidden}.hero .eyebrow,.hero p{color:#c1d6cd}.hero button{background:var(--accent);color:var(--green);border:0;margin-top:24px}.hero:after{content:'✈';position:absolute;right:45px;top:38px;transform:rotate(-18deg);font-size:150px;color:#ffffff0b;pointer-events:none}.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;padding:28px 8px}.stats strong{display:block;font-size:27px;line-height:1.4}.stats span,.muted{color:var(--muted);font-size:13px}.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.card,.panel{background:white;border:1px solid var(--line);border-radius:18px;padding:26px}.card{display:flex;flex-direction:column;align-items:flex-start;gap:12px}.card p{font-size:14px;color:var(--muted);flex:1}.icon{width:38px;height:38px;border-radius:10px;background:#e9f2e7;color:var(--green);text-align:center;line-height:38px;font-size:20px}button,.btn{font:inherit;cursor:pointer;border:1px solid var(--line);background:white;border-radius:10px;padding:11px 20px;color:var(--ink);text-decoration:none;display:inline-block;font-weight:550}button:hover{border-color:#8aa99c;background:#f1f6f0}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #79a6dc;outline-offset:3px}button:disabled{cursor:default;opacity:.5}.primary{background:var(--green);color:white;border-color:var(--green)}.primary:hover{background:#285246;color:white}.subbar,.row{display:flex;align-items:center;justify-content:space-between;gap:12px}.subbar{margin-bottom:24px}.row{flex-wrap:wrap}.tools{margin-top:28px;display:flex;gap:10px;flex-wrap:wrap}.tools button{font-size:13px;background:transparent}.panel{max-width:820px;margin:auto}.label{display:inline-block;font-size:12px;background:#edf3ea;color:#426451;border-radius:5px;padding:3px 9px}.progress{height:5px;background:#e7ede7;border-radius:6px;margin:18px 0 26px;overflow:hidden}.progress i{display:block;height:100%;background:#699773}.option{display:flex;gap:14px;align-items:flex-start;text-align:left;width:100%;margin:12px 0;padding:16px;font-weight:400;line-height:1.7}.option b{flex-shrink:0;border:1px solid var(--line);width:30px;height:30px;border-radius:7px;text-align:center}.option.selected{border-color:var(--green);background:#edf4ec}.option.correct{border-color:#73a781;background:#eef7ef}.option.wrong{border-color:#d39289;background:#fff1ee}.feedback{padding:18px;background:#f1f6ef;border-radius:10px;margin:22px 0}.feedback.bad{background:#fff3ee}.warning{font-size:13px;color:#98692e;background:#fff8e7;padding:12px;border-radius:9px;margin-top:14px}.actions{display:flex;gap:12px;justify-content:space-between;margin-top:26px}.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(44px,1fr));gap:8px;margin-top:16px}.grid button{padding:7px 2px;font-size:13px}.grid .done{background:#dfece0}.grid .active{border:2px solid var(--green)}details{margin-top:24px}summary{cursor:pointer;color:var(--muted);font-size:14px}input,select{font:inherit;padding:12px;border:1px solid var(--line);border-radius:10px;background:white;max-width:100%}input[type=search]{width:100%;margin:12px 0 20px}.field{display:flex;flex-direction:column;gap:8px;margin:20px 0}.list-item{display:block;text-align:left;width:100%;margin:10px 0;font-weight:400}.empty{text-align:center;padding:50px 20px}.score{text-align:center;padding:30px}.score strong{font-size:64px;color:var(--green);display:block}.score span{color:var(--muted)}footer{text-align:center;font-size:11px;color:#8b958e;padding:0 20px 26px;line-height:2}#toast{position:fixed;bottom:28px;left:50%;transform:translateX(-50%);background:var(--green);color:white;padding:12px 22px;border-radius:12px;display:none;z-index:9}.history{margin-top:26px}.history p{padding:12px 0;border-bottom:1px solid var(--line);font-size:14px}@media(max-width:650px){header{padding:20px}.tag{display:none}main{margin:10px auto 32px;padding:0 16px}.hero{padding:28px 24px}h1{font-size:30px}.hero:after{right:0;top:50px;font-size:100px}.stats{gap:8px;padding:24px 4px}.stats strong{font-size:23px}.stats span{font-size:11px}.cards{grid-template-columns:1fr;gap:12px}.card{padding:20px;display:grid;grid-template-columns:38px 1fr auto;gap:8px 14px}.card h3{font-size:18px}.card p{grid-column:2/4;margin:0}.card button{grid-column:3;grid-row:1;font-size:13px;padding:8px 12px}.panel{padding:20px 16px}h2{font-size:20px}.subbar{gap:8px}.subbar button{font-size:13px;padding:8px 12px}.option{padding:13px 12px}.actions button{padding:10px 14px}.row{gap:8px}}
/* Reading modes and touch-first layout */
html{ -webkit-text-size-adjust:100% }body{overflow-wrap:anywhere}button,a,input,select,summary{-webkit-tap-highlight-color:transparent;touch-action:manipulation}button{min-height:44px}.card h3 small{font-size:12px;font-weight:400;white-space:nowrap}.cards{grid-template-columns:repeat(2,minmax(0,1fr))}.unanswered-card{grid-column:1/-1}.static-option{cursor:default;background:#fff;border:1px solid var(--line);border-radius:10px}.option:disabled{opacity:1}.answer-banner{display:flex;align-items:flex-start;gap:12px;padding:17px;background:#e7f2e5;border-left:4px solid #61916a;border-radius:10px;margin-bottom:22px}.answer-banner>span:first-child{font-size:12px;white-space:nowrap;padding-top:6px}.answer-banner strong{font-size:24px;line-height:1.4}.answer-banner>span:last-child{flex:1}.answer-mark{display:block;color:#426b47;font-size:12px;margin-top:6px}.subbar strong{white-space:nowrap}.question-panel details{max-height:400px;overflow:auto}.question-panel summary{padding:12px 0}.question-panel .option span{min-width:0}.actions{position:sticky;bottom:0;background:rgba(255,255,255,.97);padding:12px 0 max(12px,env(safe-area-inset-bottom));z-index:2;border-top:1px solid var(--line)}
@media(max-width:650px){header{padding:14px 18px}.brand{font-size:18px}.logo{width:39px;height:39px;line-height:39px;font-size:24px}.hero{padding:22px}.hero h1{font-size:27px;margin:8px 0 12px}.hero .eyebrow{font-size:9px;letter-spacing:1px}.hero p{font-size:13px}.hero button{margin-top:14px;padding:10px 17px}.stats{padding:18px 2px}.cards{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.card{display:flex;align-items:flex-start;padding:16px;gap:8px;min-width:0}.card .icon{height:30px;width:30px;line-height:30px;font-size:17px}.card h3{font-size:17px}.card p{font-size:12px;line-height:1.6}.card button{width:100%;padding:8px 4px;margin-top:4px;font-size:13px}.unanswered-card{display:grid;grid-template-columns:30px 1fr auto;align-items:center;gap:6px 10px}.unanswered-card p{grid-column:2/4}.unanswered-card button{grid-column:3;grid-row:1;padding:8px 10px;margin:0;width:auto}.unanswered-card h3{font-size:16px}.tools{margin-top:18px;gap:8px}.tools button{flex:1 1 auto;font-size:12px}.subbar{position:sticky;top:0;z-index:3;background:var(--bg);padding:10px 0;margin-bottom:12px;gap:6px}.subbar strong{font-size:15px}.subbar button{font-size:12px;padding:8px 10px}.subbar .label{font-size:10px;padding:3px 5px}.panel{border-radius:14px}.question-panel{padding:18px 14px}.question-panel h2{font-size:19px;line-height:1.7;margin-bottom:20px}.option{font-size:16px;line-height:1.7;gap:10px}.answer-banner{flex-wrap:wrap;padding:14px;gap:8px}.answer-banner>span:last-child{flex-basis:100%;font-size:16px}.actions button{flex:1;min-height:48px}.progress{margin:16px 0 20px}footer{padding-bottom:calc(20px + env(safe-area-inset-bottom))}}
@media(max-width:360px){main{padding:0 12px}.card{padding:13px}.stats span{font-size:10px}.subbar strong{font-size:14px}.unanswered-card{grid-template-columns:1fr auto}.unanswered-card .icon{display:none}.unanswered-card h3{grid-column:1}.unanswered-card button{grid-column:2}.unanswered-card p{grid-column:1/3}}