:root{--ink:#203f46;--muted:#637f87;--teal:#225c65;--line:rgba(255,255,255,.9);--glass:rgba(250,254,255,.85)}*{box-sizing:border-box}body{margin:0;color:var(--ink);font-family:Inter,"PingFang SC","Microsoft YaHei",sans-serif;min-height:100vh;background:#f2f8f9}button,input,select{font:inherit}button{cursor:pointer;color:inherit}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #438b94;outline-offset:4px}button:disabled{cursor:default;opacity:.55}.filter{position:absolute;width:0;height:0}.waterscape{position:fixed;inset:0;z-index:-2;overflow:hidden;background:#edf7f7}.water{position:absolute;inset:-6%;background:url('assets/water.png') center 57%/cover;filter:url(#waterflow) contrast(1.18) brightness(1.03) saturate(1.06);will-change:transform;opacity:.92}.texture-a{animation:drift 30s ease-in-out infinite alternate}.texture-b{opacity:.23;mix-blend-mode:screen;transform:scale(1.07) rotate(2deg);animation:drift 38s ease-in-out infinite alternate-reverse}.water-light{position:absolute;inset:-35%;background:repeating-conic-gradient(from 20deg at 45% 70%,transparent 0deg 15deg,#fff9 17deg,transparent 23deg 38deg);filter:blur(18px);mix-blend-mode:soft-light;opacity:.62;animation:glide 33s linear infinite}.veil{position:absolute;inset:0;background:linear-gradient(#ffffffc7 0%,#ffffff3d 25%,#ffffff14 65%,#ffffff70 100%)}@keyframes drift{from{transform:translate(-1.5%,-1%) scale(1.04)}to{transform:translate(1.5%,1.5%) scale(1.09)}}@keyframes glide{to{transform:rotate(20deg) translate(5%,4%)}}body.still .water,body.still .water-light{animation:none;filter:none}.still .filter animate{display:none}header{height:98px;padding:0 6%;display:flex;align-items:center;gap:64px;background:#ffffff42;border-bottom:1px solid #dae8eb;backdrop-filter:blur(14px)}.brand{font-family:Georgia,serif;font-size:32px;text-decoration:none;color:var(--ink);display:flex;gap:14px;align-items:center}.drop{width:28px;height:38px;background:linear-gradient(130deg,#fff,#9bdbdf 65%,#4ab7c0);border:1px solid #a2cdd2;box-shadow:inset 3px 2px 5px white,0 4px 10px #488c9420;border-radius:75% 30% 65% 50%;transform:rotate(-30deg);font-size:0}nav{display:flex;align-self:stretch;gap:34px}.nav{background:none;border:0;position:relative;font-size:15px;letter-spacing:2px;color:var(--muted);padding:0 4px}.nav.active{color:var(--ink)}.nav.active:after{content:'';height:3px;background:#75c7c9;position:absolute;bottom:0;left:0;right:0}.settings{margin-left:auto;display:flex;gap:12px}.icon{background:#ffffff4d;border:1px solid #d5e6e9;border-radius:50%;width:40px;height:40px;font-size:22px}.icon.on{background:#cde9e9}main{max-width:1220px;margin:48px auto 30px;padding:0 30px;min-height:650px}.layout{display:grid;grid-template-columns:minmax(0,1fr) 270px;gap:26px;align-items:start}.glass{background:var(--glass);border:1px solid #fff;border-radius:28px;box-shadow:inset 0 0 0 3px #ffffff40,0 15px 40px #315e6e0e,0 2px 3px #3566730a;backdrop-filter:blur(20px)}.practice{padding:30px 36px;min-height:610px;position:relative}.eyebrow{font-size:11px;letter-spacing:3px;color:var(--muted);text-transform:uppercase}.practice-top{display:flex;justify-content:space-between;align-items:center;gap:15px}h1{font-size:22px;font-weight:500;letter-spacing:2px;margin:8px 0 16px}h2{font-size:19px;font-weight:500;margin:0 0 20px}h3{font-size:15px;font-weight:500}.bar{height:5px;background:#c9dfe466;border-radius:8px;overflow:hidden}.bar i{display:block;height:100%;background:linear-gradient(90deg,#63b9cc,#87d8ca);border-radius:8px;transition:width .5s}.controls{display:flex;gap:8px;flex-wrap:wrap;margin:22px 0 0}.chip,select{border:1px solid #d8e6e8;background:#ffffff65;border-radius:30px;padding:8px 13px;font-size:12px;color:var(--muted)}.chip.active{background:#dcefee;color:#255b60;border-color:#a7cdce}.word-area{text-align:center;padding:35px 0 27px}.word{font-family:Georgia,serif;font-size:64px;font-weight:500;line-height:1.1;margin:10px 0 18px;overflow-wrap:anywhere}.question{font-size:15px;color:#496b72;line-height:1.8}.options{display:grid;grid-template-columns:1fr 1fr;gap:14px}.option{min-height:76px;border:1px solid #fff;border-radius:19px;background:linear-gradient(145deg,#ffffff90,#edf8f861);box-shadow:inset 0 1px 2px #fff,0 5px 12px #46748308;padding:16px;font-size:16px;line-height:1.55;transition:transform .2s,background .2s,box-shadow .2s}.option:hover:not(:disabled){transform:translateY(-3px);box-shadow:0 10px 22px #37657814}.option.correct{background:#caf0e5b0;border-color:#68b7b8;opacity:1;box-shadow:inset 0 0 0 2px #ffffff80,0 0 20px #75cec340}.option.wrong{background:#f7deded0;border-color:#dbaaaa;opacity:1}.feedback{margin-top:24px;padding:19px 22px;background:#ffffff60;border:1px solid #fff;border-radius:20px;min-height:85px;display:flex;gap:12px;align-items:center}.feedback p{margin:0;line-height:1.75;font-size:14px}.feedback .sub{font-size:12px;color:var(--muted);margin-top:4px}.primary{background:linear-gradient(140deg,#357c84,#194e58);color:white;border:1px solid #27616b;border-radius:15px;padding:13px 22px;box-shadow:inset 0 1px 2px #b4e6e878,0 5px 12px #24576028;white-space:nowrap}.feedback .primary{margin-left:auto}.secondary{background:#ffffff90;border:1px solid #d5e5e5;border-radius:14px;padding:12px 18px}.aside{padding:27px 24px}.aside hr{border:0;border-top:1px solid #fff;margin:16px 0 23px}.metric{margin-bottom:24px}.metric-head{display:flex;justify-content:space-between;font-size:13px;color:var(--muted);margin-bottom:10px}.note{font-size:12px;line-height:1.9;color:var(--muted)}.aside .primary{width:100%;margin-top:15px}.tiny{font-size:12px;color:var(--muted)}.source{font-size:11px;color:#759097;text-align:center;margin-top:22px}.flash{padding:18px;background:#ffffff65;border-radius:16px;margin-top:15px;line-height:1.9}.flash strong{display:block;margin-bottom:8px}.reveal-actions{display:flex;gap:12px;justify-content:center;margin-top:18px}.panel{padding:32px}.panel-header{display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap}.search{padding:12px 18px;border:1px solid #cfdfe1;background:#ffffffaa;border-radius:16px;min-width:240px;color:var(--ink)}.library-list{margin-top:24px;display:grid;grid-template-columns:1fr 1fr;gap:14px}.entry{padding:20px;background:#ffffff65;border:1px solid #fff;border-radius:18px}.entry summary{cursor:pointer;display:flex;justify-content:space-between;gap:15px;align-items:center}.entry-word{font:24px Georgia,serif}.entry p{font-size:13px;line-height:1.8}.badge{font-size:10px;padding:5px 8px;border-radius:12px;background:#deeeed;color:#55737a}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin:26px 0}.stat{padding:24px;background:#ffffff70;border:1px solid white;border-radius:20px}.stat strong{font:42px Georgia,serif;display:block;margin:9px 0}.progress-list{display:grid;gap:10px}.progress-row{display:grid;grid-template-columns:1fr 1fr 1fr;gap:15px;padding:14px 18px;background:#ffffff60;border-radius:14px;font-size:13px}.sentence{font:24px/1.65 Georgia,serif;text-align:left;margin-bottom:15px}.sentence-label{font:11px sans-serif;letter-spacing:2px;color:var(--muted);display:block}.loading{padding:55px;text-align:center}footer{max-width:1160px;margin:0 auto;padding:12px 0 35px;display:flex;gap:20px;justify-content:space-between;color:var(--muted);font-size:11px}footer button{background:none;border:0;color:#396d75;font-size:11px;padding:3px 6px}#toast{position:fixed;bottom:25px;left:50%;transform:translateX(-50%);padding:13px 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/* Clear water highlights with a quieter, more opaque learning surface. */
.practice.glass{background:rgba(250,254,255,.87);box-shadow:inset 0 0 0 3px #ffffff70,0 18px 44px #315e6e12,0 2px 5px #3566730c}.practice .option{background:linear-gradient(145deg,#ffffffd9,#edf8f8bf)}.practice .option.correct{background:#d5f2ed;border-color:#68b7b8}.practice .option.wrong{background:#f7dede;border-color:#dbaaaa}.practice .feedback{background:rgba(255,255,255,.78)}