:root{
  --ink:#102331;
  --ink-soft:#526773;
  --paper:#fffdf7;
  --canvas:#edf2ef;
  --line:#cfd8d5;
  --coral:#f36a4a;
  --acid:#e7ff59;
  --sky:#bfe8ef;
  --mint:#169477;
  --blue:#2f6dca;
  --gold:#d89a32;
  --shadow:0 18px 55px rgba(16,35,49,.1);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  min-height:100vh;
  margin:0;
  color:var(--ink);
  font-family:"Microsoft YaHei UI","Microsoft YaHei",sans-serif;
  background:
    linear-gradient(rgba(16,35,49,.035) 1px,transparent 1px),
    linear-gradient(90deg,rgba(16,35,49,.035) 1px,transparent 1px),
    var(--canvas);
  background-size:28px 28px;
}
button,a,textarea{font:inherit}
button,a{-webkit-tap-highlight-color:transparent}
button{color:inherit}
.eyebrow{color:var(--coral);font:900 10px/1.2 Georgia,serif;letter-spacing:.16em}
.pattern-topbar{
  position:sticky;
  z-index:30;
  top:0;
  height:76px;
  display:grid;
  grid-template-columns:1fr minmax(270px,430px) 1fr;
  align-items:center;
  padding:0 24px;
  border-bottom:1px solid rgba(16,35,49,.17);
  background:rgba(255,253,247,.94);
  backdrop-filter:blur(16px);
}
.pattern-brand{width:max-content;display:flex;align-items:center;gap:12px;color:var(--ink);text-decoration:none}
.pattern-brand>b{
  width:40px;
  height:40px;
  display:grid;
  place-items:center;
  background:var(--ink);
  color:#fff;
  box-shadow:4px 4px 0 var(--acid);
  font:900 13px/1 Georgia,serif;
}
.pattern-brand span,.pattern-brand strong,.pattern-brand small{display:block}
.pattern-brand strong{font-size:14px}
.pattern-brand small{margin-top:3px;color:#75858b;font:700 10px/1.2 Georgia,serif;letter-spacing:.1em;text-transform:uppercase}
.top-progress{display:grid;grid-template-columns:auto 1fr;align-items:center;gap:14px;color:#61747d;font-size:11px;font-weight:900}
.top-progress i{height:5px;display:block;overflow:hidden;background:#dce4e1}
.top-progress em{width:0;height:100%;display:block;background:linear-gradient(90deg,var(--coral),#ff9b5f);transition:width .25s ease}
.top-exit{
  justify-self:end;
  padding:9px 13px;
  border:1px solid var(--ink);
  background:#fff;
  color:var(--ink);
  font-size:12px;
  font-weight:900;
  text-decoration:none;
  box-shadow:3px 3px 0 var(--sky);
}
.pattern-layout{
  width:min(1600px,calc(100% - 24px));
  min-height:calc(100vh - 100px);
  display:grid;
  grid-template-columns:288px minmax(540px,1fr) 250px;
  gap:14px;
  align-items:start;
  margin:12px auto;
}
.lesson-rail,.pattern-workbench,.progress-panel{
  border:1px solid rgba(16,35,49,.18);
  background:rgba(255,253,247,.97);
  box-shadow:0 7px 22px rgba(16,35,49,.045);
}
.lesson-rail{
  position:sticky;
  top:88px;
  height:calc(100vh - 100px);
  display:flex;
  flex-direction:column;
  padding:20px;
  overflow:hidden;
}
.rail-title{display:flex;align-items:flex-start;justify-content:space-between;gap:12px}
.rail-title h1{margin:6px 0 0;font:700 24px/1.1 Georgia,"Songti SC",serif}
.random-button{
  padding:7px 8px;
  border:0;
  background:#e7eeee;
  color:#526670;
  font-size:10px;
  font-weight:900;
  cursor:pointer;
}
.random-button:hover{background:var(--acid);color:var(--ink)}
.chapter-tabs{display:flex;gap:5px;overflow-x:auto;margin:17px 0 14px;padding-bottom:3px;scrollbar-width:none}
.chapter-tabs::-webkit-scrollbar{display:none}
.chapter-tabs button{
  flex:0 0 auto;
  padding:7px 9px;
  border:1px solid #d4ddda;
  background:#fff;
  color:#6d7e84;
  font-size:10px;
  font-weight:900;
  cursor:pointer;
}
.chapter-tabs button.active{border-color:var(--ink);background:var(--ink);color:#fff}
.unit-list{flex:1;min-height:0;overflow-y:auto;padding-right:5px;scrollbar-width:thin;scrollbar-color:#bdc9c6 transparent}
.unit-list section+section{margin-top:17px}
.unit-group-title{display:flex;align-items:center;gap:8px;margin-bottom:7px}
.unit-group-title>span{
  width:29px;height:29px;display:grid;place-items:center;
  background:var(--sky);font:900 10px/1 Georgia,serif;
}
.unit-group-title strong,.unit-group-title small{display:block}
.unit-group-title strong{font-size:11px}
.unit-group-title small{margin-top:2px;color:#879398;font-size:9px}
.unit-group-list{display:grid;gap:4px}
.unit-group-list button{
  position:relative;
  min-width:0;
  display:grid;
  grid-template-columns:27px minmax(0,1fr);
  gap:7px;
  align-items:center;
  padding:8px 9px;
  border:1px solid transparent;
  background:transparent;
  color:#596c75;
  text-align:left;
  cursor:pointer;
}
.unit-group-list button>span{font:700 10px/1 Georgia,serif;color:#8a989e}
.unit-group-list button>strong{overflow:hidden;font:700 10px/1.25 Georgia,"Times New Roman",serif;text-overflow:ellipsis;white-space:nowrap}
.unit-group-list button:hover{border-color:#cbd7d4;background:#fff}
.unit-group-list button.answered:after{
  content:"";position:absolute;right:7px;top:50%;width:5px;height:5px;border-radius:50%;background:var(--blue);transform:translateY(-50%);
}
.unit-group-list button.checked:after{width:7px;height:7px;background:var(--gold)}
.unit-group-list button.mastered:after{width:7px;height:7px;background:var(--mint)}
.unit-group-list button.current{
  border-color:var(--ink);
  background:var(--ink);
  color:#fff;
  box-shadow:4px 4px 0 var(--acid);
}
.unit-group-list button.current>span{color:var(--acid)}
.rail-key{display:flex;flex-wrap:wrap;gap:8px 11px;padding-top:13px;border-top:1px solid #dde4e1;color:#7b898f;font-size:9px}
.rail-key span{display:flex;align-items:center;gap:4px}
.rail-key i{width:6px;height:6px;border-radius:50%;background:#ccd6d3}
.rail-key i.answered{background:var(--blue)}.rail-key i.checked{background:var(--gold)}.rail-key i.mastered{background:var(--mint)}
.pattern-workbench{
  position:relative;
  min-height:calc(100vh - 100px);
  display:flex;
  flex-direction:column;
  padding:clamp(22px,3vw,44px);
  overflow:hidden;
}
.pattern-workbench:before{
  content:"";
  position:absolute;
  right:-70px;
  top:-100px;
  width:220px;
  height:220px;
  border:32px solid rgba(191,232,239,.34);
  border-radius:50%;
  pointer-events:none;
}
.lesson-head{position:relative;z-index:1;display:flex;justify-content:space-between;align-items:center;gap:16px}
.lesson-head>div{display:flex;align-items:center;gap:12px}
.lesson-position{color:#819097;font:800 10px/1 Georgia,serif;letter-spacing:.08em}
.mastery-button{
  padding:8px 12px;
  border:1px solid #c7d5d1;
  background:#fff;
  color:#5f726f;
  border-radius:999px;
  font-size:10px;
  font-weight:900;
  cursor:pointer;
}
.mastery-button span{color:var(--mint);font-size:14px}
.mastery-button.active{border-color:#93cbbd;background:#e7f7f1;color:#11725b}
.mastery-button.active span{font-size:0}.mastery-button.active span:before{content:"◆";font-size:11px}
.lesson-card{position:relative;margin-top:21px;border:1px solid var(--ink);background:var(--paper);box-shadow:8px 8px 0 var(--sky)}
.lesson-copy{padding:25px 28px 22px}
.chapter-name{margin:0 0 8px;color:var(--coral);font-size:10px;font-weight:900;letter-spacing:.08em}
.lesson-copy h1{margin:0;font:700 clamp(27px,3vw,43px)/1.08 Georgia,"Times New Roman",serif;letter-spacing:-.035em}
.lesson-copy>p:last-child{margin:12px 0 0;color:var(--ink-soft);font-size:13px}
.pattern-formula{
  display:grid;
  grid-template-columns:96px 1fr;
  align-items:stretch;
  border-top:1px solid var(--ink);
  border-bottom:1px solid var(--ink);
  background:#f4f6ef;
}
.pattern-formula>span{
  display:grid;place-items:center;padding:14px;
  border-right:1px solid var(--ink);
  background:var(--acid);
  font-size:11px;font-weight:950;
}
.pattern-formula>div{padding:18px 22px}
.pattern-line{margin:0;font:700 clamp(16px,1.5vw,21px)/1.55 Georgia,"Times New Roman",serif}
.pattern-line+.pattern-line{margin-top:8px;padding-top:8px;border-top:1px dashed #c5cfca}
.pattern-line mark{
  padding:2px 4px;
  background:#d9eff4;
  color:#164d58;
  box-decoration-break:clone;
  -webkit-box-decoration-break:clone;
}
.pattern-line.pattern-2 mark{background:#ffe1d8;color:#8d3523}
.example-section{padding:21px 28px 23px}
.section-label{display:flex;justify-content:space-between;align-items:center;margin-bottom:12px}
.section-label>span{font-size:11px;font-weight:950}
.section-label small{color:#89969a;font-size:9px}
.example-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:9px}
.example-grid article{position:relative;min-width:0;padding:15px 15px 15px 42px;border:1px solid #d6dfdc;background:#fff}
.example-number{position:absolute;left:13px;top:15px;color:var(--coral);font:900 10px/1 Georgia,serif}
.example-grid p{margin:0}
.example-zh{color:#5b6e76;font-size:11px;line-height:1.65}
.example-en{margin-top:7px!important;color:var(--ink);font:700 14px/1.55 Georgia,"Times New Roman",serif}
.warning-note{display:grid;grid-template-columns:34px 1fr;gap:10px;align-items:center;margin:0 28px 25px;padding:11px 13px;background:#fff4df;border-left:4px solid var(--gold)}
.warning-note>b{width:28px;height:28px;display:grid;place-items:center;border-radius:50%;background:var(--gold);color:#fff;font:900 17px/1 Georgia,serif}
.warning-note p,.warning-note strong,.warning-note span{display:block;margin:0}
.warning-note strong{font-size:9px;letter-spacing:.08em}
.warning-note span{margin-top:3px;color:#6e5b37;font-size:10px;line-height:1.5}
.warning-note code{padding:1px 4px;background:rgba(255,255,255,.75);color:#7e4f13;font:700 10px/1.3 Consolas,monospace}
.drill-card{margin-top:22px;border:1px solid #ccd7d4;background:#fff}
.drill-head{display:flex;justify-content:space-between;align-items:center;padding:17px 21px;border-bottom:1px solid #d9e1df}
.drill-head h2{margin:4px 0 0;font:700 22px/1 Georgia,"Songti SC",serif}
.exercise-switcher{display:flex;gap:6px}
.exercise-switcher button{
  position:relative;
  width:31px;height:31px;
  border:1px solid #cbd6d3;background:#fff;color:#74858b;
  font:800 10px/1 Georgia,serif;cursor:pointer;
}
.exercise-switcher button.answered{border-color:#aabfdc;background:#edf4ff;color:var(--blue)}
.exercise-switcher button.checked{border-color:#dfbc7f;background:#fff4df;color:#a76f16}
.exercise-switcher button.current{border-color:var(--ink);background:var(--ink);color:#fff;box-shadow:3px 3px 0 var(--acid)}
.prompt-paper{position:relative;padding:24px 27px;background:#fffdf7}
.prompt-paper:after{content:"中 → EN";position:absolute;right:20px;top:16px;color:rgba(16,35,49,.08);font:900 32px/1 Georgia,serif;pointer-events:none}
.prompt-paper>span{color:#92744b;font-size:9px;font-weight:950;letter-spacing:.12em}
.prompt-main{position:relative;z-index:1;display:grid;grid-template-columns:minmax(0,1fr) minmax(165px,220px);gap:22px;align-items:center;margin-top:13px}
.prompt-paper p{max-width:800px;margin:0;font:700 clamp(20px,2vw,28px)/1.55 Georgia,"Songti SC",serif}
.given-vocabulary{padding:12px 13px;border:1px solid #d6d0be;background:#fff}
.given-vocabulary>b{display:block;margin-bottom:8px;color:#8a7858;font-size:9px;letter-spacing:.08em}
.given-vocabulary>div{display:flex;flex-wrap:wrap;gap:5px}
.given-vocabulary span{padding:5px 7px;background:#e7f3f5;color:#235c67;font:700 10px/1.2 Georgia,"Times New Roman",serif}
.answer-box{margin:0 21px 21px;border:1px solid #ced9d6;background:#fff}
.answer-head,.answer-foot{display:flex;justify-content:space-between;align-items:center}
.answer-head{padding:10px 13px;border-bottom:1px solid #e0e6e4}
.answer-head label{font-size:10px;font-weight:950}.answer-head span,.answer-foot{color:#849197;font-size:9px}
.answer-box textarea{
  width:100%;min-height:115px;display:block;resize:vertical;padding:16px 18px;
  border:0;outline:0;background:#fff;color:#132739;
  font:17px/1.7 Georgia,"Times New Roman",serif;
}
.answer-box:focus-within{border-color:#8eb1c0;box-shadow:0 0 0 3px rgba(47,109,202,.08)}
.answer-foot{padding:9px 12px;border-top:1px solid #e4e9e7}
.answer-foot kbd{padding:1px 4px;border:1px solid #d4ddda;border-bottom-width:2px;background:#f7f9f8;color:#61737b;font-size:8px}
.reference-answer{
  display:grid;
  grid-template-columns:38px 1fr;
  gap:12px;
  align-items:start;
  margin:0 21px 21px;
  padding:15px 17px;
  border:1px solid #9fd4c5;
  background:#eaf8f3;
  animation:answer-in .22s ease-out;
}
.reference-answer[hidden]{display:none}
.reference-mark{width:38px;height:38px;display:grid;place-items:center;border-radius:50%;background:var(--mint);color:#fff;font:900 20px/1 Georgia,serif}
.reference-answer span{color:#247a65;font:900 9px/1 Georgia,serif;letter-spacing:.12em}
.reference-answer p{margin:6px 0 0;color:#154f40;font:700 16px/1.6 Georgia,"Times New Roman",serif}
@keyframes answer-in{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.workbench-actions{display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:10px;margin-top:auto;padding-top:23px}
.workbench-actions button{min-height:43px;padding:0 16px;border-radius:0;font-size:11px;font-weight:950;cursor:pointer}
.nav-button{justify-self:start;border:1px solid #cad5d2;background:#fff;color:#5d7078}
.nav-button.next{justify-self:end}
.nav-button:hover:not(:disabled){border-color:var(--ink);color:var(--ink)}
.nav-button:disabled{opacity:.35;cursor:not-allowed}
.check-button{min-width:152px;border:1px solid var(--ink);background:var(--ink);color:#fff;box-shadow:4px 4px 0 var(--acid)}
.check-button:hover{background:#1b3d50}.check-button.is-open{background:#e4ebe9;color:#4f626b;box-shadow:none}
.progress-panel{position:sticky;top:88px;padding:22px}
.progress-panel h2{margin:7px 0 0;font:700 23px/1.25 Georgia,"Songti SC",serif}
.progress-ring{
  --progress:0deg;
  position:relative;
  width:142px;height:142px;
  display:grid;place-items:center;
  margin:25px auto;
  border-radius:50%;
  background:conic-gradient(var(--coral) var(--progress),#e2e9e6 0);
}
.progress-ring:before{content:"";position:absolute;inset:10px;border-radius:50%;background:var(--paper)}
.progress-ring div{position:relative;text-align:center}
.progress-ring strong{font:700 39px/1 Georgia,serif}.progress-ring span{color:#879499;font:12px/1 Georgia,serif}
.progress-panel dl{margin:0;border-top:1px solid #dce4e1}
.progress-panel dl div{display:flex;justify-content:space-between;padding:11px 1px;border-bottom:1px solid #e0e6e4}
.progress-panel dt{color:#718289;font-size:10px}.progress-panel dd{margin:0;font:700 13px/1 Georgia,serif}
.study-rule{margin-top:18px;padding:14px;background:#edf6f7;border-left:4px solid #74bac5}
.study-rule b{font-size:10px}.study-rule ol{margin:8px 0 0;padding-left:18px;color:#5c7179;font-size:9px;line-height:1.8}
.pattern-error{width:min(620px,calc(100% - 30px));margin:40px auto;padding:23px;border:1px dashed #b9c7c3;background:#fff;text-align:center;color:#65777f}
@media(max-width:1200px){
  .pattern-layout{grid-template-columns:270px minmax(520px,1fr)}
  .progress-panel{display:none}
}
@media(max-width:860px){
  .pattern-topbar{height:68px;grid-template-columns:1fr auto;padding:0 14px}
  .top-progress{display:none}
  .pattern-layout{width:calc(100% - 14px);display:flex;flex-direction:column;margin:7px auto}
  .pattern-workbench{order:1;width:100%;min-height:calc(100vh - 82px);padding:21px}
  .lesson-rail{position:static;order:2;width:100%;height:auto;padding:16px}
  .unit-list{max-height:none;overflow:visible}
  .unit-group-list{grid-template-columns:repeat(2,minmax(0,1fr))}
  .unit-group-list button>strong{white-space:normal}
  .rail-key{margin-top:14px}
}
@media(max-width:620px){
  .pattern-brand small{display:none}
  .top-exit{padding:8px 9px}
  .pattern-workbench{padding:15px}
  .lesson-head{align-items:flex-start}
  .lesson-head>div{display:block}
  .lesson-position{display:block;margin-top:5px}
  .mastery-button{padding:7px 9px}
  .lesson-card{box-shadow:5px 5px 0 var(--sky)}
  .lesson-copy{padding:21px 19px}
  .lesson-copy h1{font-size:27px}
  .pattern-formula{grid-template-columns:1fr}
  .pattern-formula>span{display:block;border-right:0;border-bottom:1px solid var(--ink);padding:9px 13px}
  .pattern-formula>div{padding:15px}
  .pattern-line{font-size:16px}
  .example-section{padding:18px}
  .example-grid{grid-template-columns:1fr}
  .warning-note{margin:0 18px 20px}
  .drill-head{padding:15px;align-items:flex-end}
  .drill-head h2{font-size:19px}
  .exercise-switcher button{width:28px;height:28px}
  .prompt-paper{padding:21px 18px}
  .prompt-paper:after{font-size:23px}
  .prompt-paper p{font-size:20px}
  .prompt-main{grid-template-columns:1fr;gap:14px}
  .given-vocabulary{padding:10px}
  .answer-box,.reference-answer{margin-right:14px;margin-left:14px}
  .answer-foot span:first-child{display:none}
  .workbench-actions{grid-template-columns:1fr 1fr}
  .check-button{grid-column:1/-1;grid-row:1;width:100%}
  .nav-button,.nav-button.next{width:100%;justify-self:stretch}
  .unit-group-list{grid-template-columns:1fr}
}