/* Translation Studio · 样式（和写作台同一套纸感配色） */
:root{
  --ink:#1a1a1a;--ink-soft:#3d4450;--muted:#6b7280;--line:#e3e5e8;--line-strong:#d3d6db;
  --accent:#0f4c81;--accent-soft:#eaf1f8;--bg:#fbfaf7;--paper:#fff;
  --good:#2f7d5d;--good-soft:#e9f5ef;--warn:#b45309;--warn-soft:#fdf3e3;--bad:#b3261e;--bad-soft:#fdeceb;
  --ui:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --serif:Georgia,"Songti SC","Noto Serif SC",serif;
  --mono:ui-monospace,Menlo,Consolas,monospace;
  --topbar:58px;
}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font:15px/1.6 var(--ui)}
a{color:var(--accent);text-decoration:none}
button{font:inherit;color:inherit;cursor:pointer}
.app{max-width:1040px;margin:0 auto;padding:28px 22px 80px}
.topbar{position:sticky;top:0;z-index:40;height:var(--topbar);display:flex;align-items:center;gap:20px;padding:0 20px;
  background:rgba(251,250,247,.94);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.brand{display:flex;align-items:center;gap:10px;color:inherit}
.brand-mark{width:30px;height:30px;border-radius:8px;background:var(--accent);color:#fff;display:grid;place-items:center;font:700 16px var(--serif)}
.brand-text{display:flex;flex-direction:column;font-weight:700;font-size:14.5px}
.brand-text em{font:400 11px var(--ui);color:var(--muted);font-style:normal}
.nav{display:flex;gap:4px;flex:1}
.nav a{padding:6px 11px;border-radius:7px;color:var(--ink-soft);font-size:13.5px}
.nav a.active{background:var(--accent);color:#fff}
.who{border:1px solid var(--line-strong);background:var(--paper);border-radius:999px;padding:5px 12px;font-size:12.5px;color:var(--ink-soft)}
.site-foot{max-width:1040px;margin:0 auto;padding:10px 22px 34px;color:var(--muted);font-size:11.5px;display:flex;gap:12px;flex-wrap:wrap;
  border-top:1px solid var(--line);padding-top:14px}
.site-foot a{color:var(--muted)}

h1{font:700 27px/1.35 var(--serif);margin:0 0 8px}
.page-head{margin-bottom:22px}
.page-head p{color:var(--muted);font-size:13.5px;margin:0}
.card{background:var(--paper);border:1px solid var(--line);border-radius:10px}
.panel{padding:18px 20px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;border:1px solid var(--line-strong);background:var(--paper);
  border-radius:8px;padding:9px 16px;font-size:14px;transition:.15s}
.btn:hover{border-color:#b9bec6}
.btn-primary{background:var(--accent);border-color:var(--accent);color:#fff}
.btn-primary:hover{background:#0d4373}
.btn-sm{padding:6px 11px;font-size:12.5px}
.btn:disabled{opacity:.4;cursor:not-allowed}
.chip{display:inline-flex;align-items:center;border:1px solid var(--line);background:#fbfaf8;border-radius:999px;padding:3px 9px;font-size:11.5px;color:var(--ink-soft)}
.chip.accent{border-color:#cfe0ef;background:var(--accent-soft);color:var(--accent)}
.muted{color:var(--muted)}
.small{font-size:12.5px}

.hero{padding:8px 0 18px}
.hero p{color:var(--muted);max-width:640px;font-size:14.5px}
.section-head{display:flex;align-items:baseline;justify-content:space-between;margin:26px 0 12px}
.section-head h2{font-size:15px;letter-spacing:.02em;margin:0}
.level-tabs{display:flex;gap:6px;flex-wrap:wrap;margin:14px 0 18px}
.level-tabs button{border:1px solid var(--line);background:var(--paper);border-radius:999px;padding:5px 13px;font-size:12.5px;color:var(--muted)}
.level-tabs button.on{background:var(--ink);border-color:var(--ink);color:#fff}
.topic-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:12px}
.topic-card{padding:16px 18px;text-align:left;transition:.15s;cursor:pointer}
.topic-card:hover{border-color:var(--accent);transform:translateY(-1px)}
.topic-card b{display:block;font-size:15px;margin-bottom:3px}
.topic-card .en{font-size:11.5px;color:var(--muted);letter-spacing:.02em}
.topic-card .cnt{font-size:12px;color:var(--muted);margin-top:8px}
.placeholder-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:12px}
.placeholder{padding:16px 18px;border-style:dashed;opacity:.72}
.placeholder b{display:block;font-size:14px}
.placeholder span{font-size:12px;color:var(--muted)}

/* 练习页 */
.practice-head{display:flex;align-items:flex-start;justify-content:space-between;gap:14px;flex-wrap:wrap;margin-bottom:16px}
.q-item{padding:16px 18px;margin-bottom:12px}
.q-top{display:flex;align-items:center;gap:8px;margin-bottom:8px}
.q-index{font:700 12px var(--mono);color:var(--muted)}
.q-zh{font:16.5px/1.85 var(--serif);margin:0 0 10px}
textarea.answer{width:100%;min-height:74px;border:1px solid var(--line-strong);border-radius:8px;padding:10px 12px;
  font:15px/1.7 var(--serif);resize:vertical;background:#fff}
textarea.answer:focus{outline:2px solid var(--accent-soft);border-color:var(--accent)}
.submit-bar{position:sticky;bottom:0;background:rgba(251,250,247,.96);border-top:1px solid var(--line);padding:12px 0;
  display:flex;align-items:center;gap:12px;justify-content:flex-end;backdrop-filter:blur(6px)}
.submit-bar .hint{margin-right:auto;font-size:12.5px;color:var(--muted)}

/* 结果 */
.score-hero{display:flex;align-items:center;gap:24px;padding:20px 22px;margin-bottom:14px}
.score-big{font:700 48px/1 var(--serif)}
.score-big span{font-size:16px;color:var(--muted);font-family:var(--ui)}
.r-item{padding:14px 16px;margin-bottom:10px}
.r-head{display:flex;align-items:center;gap:10px;margin-bottom:6px}
.r-score{font:700 16px var(--serif);min-width:44px}
.r-score.good{color:var(--good)}.r-score.mid{color:var(--warn)}.r-score.bad{color:var(--bad)}
.r-zh{font:15px/1.7 var(--serif);color:var(--ink-soft);margin:0 0 6px}
.r-line{font-size:13.5px;line-height:1.75;margin:3px 0}
.r-line b{font-weight:600;color:var(--muted);font-size:11.5px;letter-spacing:.06em;margin-right:6px}
.r-line.answer{font-family:var(--serif)}
.r-line.fix{color:var(--good);font-family:var(--serif)}
.r-issues{margin:6px 0 0;padding-left:18px;font-size:12.5px;color:var(--ink-soft)}
.r-issues li{margin-bottom:2px}
.tag{font-size:10.5px;border-radius:4px;padding:2px 6px;background:var(--bad-soft);color:var(--bad);border:1px solid #f0c9c6}

/* 教师 */
.t-head{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;align-items:flex-start}
.t-actions{display:flex;gap:8px;flex-wrap:wrap}
.t-filters{display:flex;gap:8px;flex-wrap:wrap;padding:12px 14px;margin-bottom:14px;align-items:center}
.t-filters input,.t-filters select{border:1px solid var(--line-strong);border-radius:7px;padding:7px 10px;font:13px var(--ui);background:#fff}
.stat-row{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-bottom:14px}
.stat{padding:14px 16px;border:1px solid var(--line);border-radius:10px;background:var(--paper)}
.stat b{display:block;font:700 24px/1.2 var(--serif)}
.stat span{font-size:12px;color:var(--muted)}
.t-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-bottom:14px}
.bars{display:flex;flex-direction:column;gap:8px}
.bar-row{display:grid;grid-template-columns:64px 1fr auto;gap:8px;align-items:center;font-size:12.5px}
.bar{background:#eef1f4;border-radius:4px;height:16px;position:relative;overflow:hidden}
.bar i{display:block;height:100%;background:#cfe0ef}
.bar b{position:absolute;right:6px;top:0;line-height:16px;font-size:11px}
table.rt{width:100%;border-collapse:collapse;font-size:12.5px}
table.rt th{text-align:left;font-size:11px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);padding:8px;border-bottom:1px solid var(--line)}
table.rt td{padding:9px 8px;border-bottom:1px solid var(--line);vertical-align:top}
table.rt tr.row{cursor:pointer}
table.rt tr.row:hover{background:#fcfbf8}
.ai-box{margin-top:14px;padding:16px 18px;border:1px solid #cfe0ef;background:#f7fbfe;border-radius:10px}
.ai-box h3{margin:0 0 8px;font-size:14px}
.ai-box ul{margin:6px 0 0;padding-left:18px;font-size:13px;line-height:1.8}
.lesson{border-top:1px dashed var(--line);padding-top:8px;margin-top:8px;font-size:13px}

/* 弹层 */
.modal{position:fixed;inset:0;z-index:80;background:rgba(26,26,26,.42);display:grid;place-items:center;padding:20px}
.modal-card{width:min(460px,100%);background:var(--paper);border-radius:12px;padding:22px;box-shadow:0 24px 50px -18px rgba(0,0,0,.4)}
.modal-card h2{margin:0 0 6px;font:700 18px/1.4 var(--serif)}
.modal-card .hint{font-size:12.5px;color:var(--muted);margin:0 0 14px;white-space:pre-line}
.field{margin-bottom:12px}
.field label{display:block;font-size:12px;color:var(--muted);margin-bottom:5px}
.field input,.field select,.field textarea{width:100%;border:1px solid var(--line-strong);border-radius:7px;padding:9px 11px;font:14px var(--ui)}
.modal-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:16px}
.detail-card{width:min(760px,100%);max-height:86vh;overflow-y:auto;background:var(--paper);border-radius:12px;padding:22px}
.toast-host{position:fixed;left:50%;bottom:24px;transform:translateX(-50%);z-index:90;display:flex;flex-direction:column;gap:8px}
.toast{background:#1f2328;color:#fff;border-radius:8px;padding:9px 15px;font-size:13px}
.toast.bad{background:var(--bad)}
.toast.good{background:var(--good)}
.empty{padding:40px 20px;text-align:center;color:var(--muted)}
.empty strong{display:block;color:var(--ink);margin-bottom:6px}
.loading{padding:40px;text-align:center;color:var(--muted)}
@media (max-width:880px){
  .stat-row{grid-template-columns:repeat(2,1fr)}
  .t-grid{grid-template-columns:1fr}
  .nav a{padding:6px 8px;font-size:12.5px}
  .brand-text em{display:none}
}
@media (max-width:600px){
  .app{padding:18px 14px 70px}
  .topbar{gap:10px;padding:0 12px}
  .brand-text{display:none}
}