:root{
  --bg:#f2f5f9; --card:#fff; --ink:#182233; --sub:#64748b;
  --brand:#0f4c75; --brand2:#1976a8; --accent:#e9f3f9; --accent2:#f6fafd;
  --ok:#2e7d52; --warn:#b7791f; --bad:#c0392b; --line:#e2e8f0;
  --shadow:0 1px 2px rgba(16,42,67,.05),0 4px 16px rgba(16,42,67,.06);
  --shadow-lg:0 10px 40px rgba(13,49,80,.16);
  --grad:linear-gradient(135deg,#0d3a5c 0%,#0f4c75 45%,#1976a8 100%);
  --radius:14px;
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}
html,body{margin:0;padding:0;background:var(--bg);color:var(--ink);
  font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei","Segoe UI",sans-serif;
  font-size:15px;line-height:1.55;
  background-image:radial-gradient(rgba(15,76,117,.045) 1px,transparent 1px);
  background-size:22px 22px}
a{color:var(--brand2);text-decoration:none}
button{font-family:inherit}

/* ===== 顶栏 ===== */
header.bar{position:sticky;top:0;z-index:50;background:var(--grad);color:#fff;
  padding:11px 16px;display:flex;align-items:center;gap:10px;flex-wrap:wrap;
  box-shadow:0 2px 12px rgba(9,42,68,.28)}
header.bar::after{content:"";position:absolute;left:0;right:0;bottom:-1px;height:3px;
  background:linear-gradient(90deg,#3ddad7,#ffd166,#ef6c57);opacity:.85}
header.bar .logo{font-size:16.5px;font-weight:800;letter-spacing:.6px;flex:1;
  display:flex;align-items:center;gap:8px}
header.bar .logo::before{content:"";width:9px;height:9px;border-radius:50%;
  background:#5eead4;box-shadow:0 0 8px #5eead4;flex:0 0 9px}
header.bar .who{font-size:12px;opacity:.95;text-align:right;line-height:1.35}
header.bar .who b{font-weight:700}
header.bar .out{font-size:12px;border:1px solid rgba(255,255,255,.5);background:rgba(255,255,255,.1);
  color:#fff;padding:5px 12px;border-radius:20px;cursor:pointer;transition:background .15s}
header.bar .out:hover{background:rgba(255,255,255,.24)}

/* ===== 布局 ===== */
main{max-width:920px;margin:0 auto;padding:16px 14px 34px}
section.panel{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  margin-bottom:14px;overflow:hidden;box-shadow:var(--shadow)}
.panel .ph{padding:15px 18px 6px}
.panel h2{margin:0 0 4px;font-size:16.5px;font-weight:800;color:var(--brand);letter-spacing:.2px}
.panel .hint{margin:0;font-size:12.5px;color:var(--sub)}
.panel .pb{padding:10px 18px 16px}

/* ===== Tab ===== */
nav.tabs{display:flex;gap:5px;margin-bottom:15px;background:var(--card);box-shadow:var(--shadow);
  border:1px solid var(--line);border-radius:var(--radius);padding:6px}
nav.tabs button{flex:1;border:0;background:transparent;padding:9px 4px;font-size:14px;
  color:var(--sub);border-radius:10px;cursor:pointer;font-weight:600;transition:all .18s}
nav.tabs button:hover{color:var(--brand2);background:var(--accent2)}
nav.tabs button.on{background:var(--grad);color:#fff;font-weight:700;
  box-shadow:0 3px 10px rgba(15,76,117,.32)}

/* ===== 通用控件 ===== */
.btn{display:inline-block;border:0;background:var(--grad);color:#fff;padding:10px 18px;
  font-size:15px;border-radius:10px;cursor:pointer;font-weight:700;letter-spacing:.3px;
  box-shadow:0 3px 10px rgba(15,76,117,.28);transition:transform .12s,box-shadow .12s}
.btn:hover{box-shadow:0 5px 16px rgba(15,76,117,.36)}
.btn:active{transform:translateY(1px)}
.btn.ghost{background:#fff;color:var(--brand2);border:1.5px solid var(--brand2);box-shadow:none}
.btn.ghost:hover{background:var(--accent2)}
.btn.danger{background:linear-gradient(135deg,#a93226,#c0392b)}
.btn.small{padding:5px 12px;font-size:13px;border-radius:8px}
input,select,textarea{width:100%;padding:11px 13px;font-size:16px;border:1.5px solid var(--line);
  border-radius:10px;background:#fff;color:var(--ink);outline:none;font-family:inherit;transition:border .15s,box-shadow .15s}
input:focus,select:focus,textarea:focus{border-color:var(--brand2);box-shadow:0 0 0 3.5px rgba(25,118,168,.14)}
label.fl{display:block;font-size:13px;color:var(--sub);margin:12px 0 4px;font-weight:600}
.field-row{display:flex;gap:10px}
.field-row > div{flex:1}
.err-msg{color:var(--bad);font-size:13px;margin-top:8px;min-height:18px}
.ok-msg{color:var(--ok);font-size:13px;margin-top:8px}
.muted{color:var(--sub);font-size:12.5px}
.badge{display:inline-block;font-size:12px;padding:2px 10px;border-radius:12px;background:var(--accent);color:var(--brand);font-weight:600}
table.grid{width:100%;border-collapse:collapse;font-size:13.5px}
table.grid th,table.grid td{padding:8px 8px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
table.grid th{color:var(--sub);font-weight:700;white-space:nowrap;font-size:12.5px;background:var(--accent2)}
table.grid tr:hover td{background:#fafcfe}
.tscroll{overflow-x:auto}

/* ===== 登录页 ===== */
body.login{display:flex;min-height:100vh;align-items:center;justify-content:center;padding:20px;
  background:linear-gradient(160deg,#0b3355 0%,#0f4c75 48%,#1d84b5 100%);position:relative;overflow:hidden}
body.login::before,body.login::after{content:"";position:absolute;border-radius:50%;
  border:1.5px solid rgba(255,255,255,.14)}
body.login::before{width:420px;height:420px;top:-140px;right:-120px}
body.login::after{width:300px;height:300px;bottom:-110px;left:-90px}
.login-card{background:#fff;border-radius:20px;padding:28px 26px 24px;width:100%;max-width:390px;
  box-shadow:var(--shadow-lg);position:relative;z-index:1}
.login-card::before{content:"";display:block;width:44px;height:5px;border-radius:3px;margin:0 auto 14px;
  background:linear-gradient(90deg,#3ddad7,#ffd166,#ef6c57)}
.login-card h1{margin:0 0 2px;font-size:21px;color:var(--brand);text-align:center;letter-spacing:.5px}
.login-card p.sub{margin:0 0 14px;font-size:12.5px;color:var(--sub);text-align:center}
.login-tabs{display:flex;gap:6px;margin-bottom:8px;background:var(--bg);padding:5px;border-radius:12px}
.login-tabs button{flex:1;border:0;background:transparent;padding:9px;font-size:14px;border-radius:9px;
  cursor:pointer;color:var(--sub);font-weight:700;transition:all .18s}
.login-tabs button.on{background:#fff;color:var(--brand);box-shadow:0 2px 8px rgba(0,0,0,.1)}
.login-note{margin-top:14px;font-size:12px;color:var(--sub);background:var(--accent2);
  border:1px dashed var(--line);border-radius:10px;padding:10px 12px;line-height:1.65}

/* ===== 模块/单元卡片 ===== */
.mod-card{border:1px solid var(--line);border-radius:var(--radius);margin-bottom:11px;background:#fff;
  overflow:hidden;box-shadow:var(--shadow);transition:box-shadow .18s}
.mod-card:hover{box-shadow:0 4px 20px rgba(16,42,67,.1)}
.mod-card .mh{padding:13px 15px;display:flex;align-items:center;gap:10px;cursor:pointer}
.mod-card .mh::before{content:"";width:5px;height:22px;border-radius:3px;background:var(--brand2);flex:0 0 5px}
.mod-card:nth-of-type(4n+2) .mh::before{background:#2e7d52}
.mod-card:nth-of-type(4n+3) .mh::before{background:#b7791f}
.mod-card:nth-of-type(4n+4) .mh::before{background:#8e5aa8}
.mod-card .mh .t{flex:1;font-weight:700;font-size:15px}
.mod-card .mh .d{font-size:12px;color:var(--sub)}
.mod-card .units{padding:0 14px 13px;display:none}
.mod-card.open .units{display:block}
.unit-row{display:flex;align-items:center;gap:8px;padding:10px 12px;border:1px solid var(--line);
  border-radius:10px;margin-bottom:7px;cursor:pointer;background:#fff;transition:all .15s}
.unit-row:hover{border-color:var(--brand2);background:var(--accent);transform:translateX(2px)}
.unit-row .n{flex:1;font-size:14px;font-weight:600}
.unit-row .c{font-size:12px;color:var(--sub)}

/* ===== 练习界面 ===== */
.practice-cn{font-size:18px;font-weight:600;line-height:1.6;margin:6px 0 10px}
.practice-tip{font-size:12.5px;color:var(--sub);background:var(--accent2);border:1px solid var(--line);
  border-radius:10px;padding:9px 13px;margin-bottom:10px}
.practice-ref{display:none;font-size:13px;color:var(--brand2);background:var(--accent);
  border-radius:10px;padding:8px 12px;margin-bottom:10px}
.practice-ref.show{display:block}
.practice-input{margin-top:10px}
.mic-btn{width:100%;padding:13px;font-size:16px;border:0;border-radius:12px;background:var(--ok);
  color:#fff;font-weight:600;cursor:pointer;margin-top:10px}
.mic-btn.rec{background:var(--bad);animation:pulse 1.2s infinite}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.65}}
.score-box{margin-top:12px;border-radius:12px;padding:12px 14px;display:none}
.score-box.show{display:block}
.score-box .sc{font-size:26px;font-weight:800}
.score-box .cm{font-size:13.5px;margin-top:2px}
.score-box.lv-perfect,.score-box.lv-great{background:#e8f5ee;color:var(--ok)}
.score-box.lv-good{background:#eef4fb;color:var(--brand2)}
.score-box.lv-fair{background:#fdf6e3;color:var(--warn)}
.score-box.lv-weak,.score-box.lv-empty{background:#fdecea;color:var(--bad)}
.wdiff{margin-top:8px;font-size:13.5px;line-height:2}
.wdiff .same{color:var(--ok)}
.wdiff .missing{color:var(--bad);text-decoration:underline;font-weight:600}
.wdiff .extra{color:var(--warn);text-decoration:line-through}

/* ===== 对话区 ===== */
#coze-chat{width:100%;height:calc(100vh - 218px);min-height:520px;max-height:780px;background:#fff;position:relative;overflow:hidden}
.coze-placeholder{padding:30px 20px;text-align:center;color:var(--sub);font-size:14px;line-height:2}
/* SDK 根节点强制填满容器：防止容器内残余占位节点把聊天区顶出去导致输入框被裁剪 */
#coze-chat > .coze-chat-sdk{position:absolute;inset:0;width:100%;height:100%}

/* ===== 页脚 ===== */
footer.icp{text-align:center;padding:16px 12px;font-size:12px;color:var(--sub)}
footer.icp a{color:var(--sub)}

/* ===== 统计 ===== */
.stat-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:10px;padding:14px 18px}
.stat{background:var(--accent2);border:1px solid var(--line);border-radius:12px;padding:13px 14px;position:relative;overflow:hidden}
.stat::before{content:"";position:absolute;left:0;top:0;bottom:0;width:4px;background:var(--brand2);opacity:.7}
.stat .v{font-size:23px;font-weight:800;color:var(--brand);line-height:1.25}
.stat .k{font-size:12px;color:var(--sub)}

/* ===== 跟读训练 ===== */
.seg{display:flex;gap:6px;background:#e6ecf3;padding:5px;border-radius:12px;margin-bottom:12px}
.seg button{flex:1;border:0;background:transparent;padding:9px;font-size:14px;border-radius:9px;
  cursor:pointer;color:var(--sub);font-weight:700;transition:all .18s}
.seg button.on{background:#fff;color:var(--brand);box-shadow:0 2px 8px rgba(0,0,0,.1)}

.item-row{display:flex;align-items:center;gap:10px;padding:10px 12px;border:1px solid var(--line);
  border-radius:11px;margin-bottom:7px;cursor:pointer;background:#fff;transition:all .15s}
.item-row:hover{border-color:var(--brand2);background:var(--accent2);transform:translateX(2px)}
.item-row .ix{width:27px;height:27px;flex:0 0 27px;border-radius:50%;background:var(--accent);color:var(--brand2);
  font-size:12px;display:flex;align-items:center;justify-content:center;font-weight:800}
.item-row .tx{flex:1;min-width:0}
.item-row .en{font-size:14.5px;font-weight:700;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.item-row .cn{font-size:12.5px;color:var(--sub);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.item-row .sc{font-size:12px;font-weight:800;padding:2px 9px;border-radius:10px;background:var(--bg);color:var(--sub);flex:0 0 auto}
.item-row .sc.hi{background:#e8f5ee;color:var(--ok)}
.item-row .sc.mid{background:#fdf6e3;color:var(--warn)}
.item-row .sc.lo{background:#fdecea;color:var(--bad)}

/* 练习卡 */
.drill{background:#fff;border:1px solid var(--line);border-radius:16px;padding:18px 17px;margin-bottom:12px;box-shadow:var(--shadow)}
.drill .bar2{display:flex;align-items:center;gap:10px;margin-bottom:14px}
.drill .bar2 .pg{flex:1;font-size:12.5px;color:var(--sub)}
.progline{height:6px;background:#e6ecf3;border-radius:4px;overflow:hidden;margin-top:6px}
.progline > i{display:block;height:100%;background:linear-gradient(90deg,#1976a8,#3ddad7);border-radius:4px;transition:width .3s}
.target-en{font-size:25px;font-weight:800;line-height:1.45;color:var(--brand);margin:4px 0 6px;word-break:break-word}
.target-en.blur{filter:blur(7px);user-select:none}
.target-ipa{font-size:14px;color:var(--brand2);margin-bottom:8px;letter-spacing:.3px}
.target-cn{font-size:15px;color:var(--sub);margin-bottom:10px}

.play-btn{width:100%;padding:12px;font-size:15px;border:1.5px solid var(--brand2);background:#fff;color:var(--brand2);
  border-radius:12px;font-weight:700;cursor:pointer;margin-bottom:10px;transition:all .15s}
.play-btn:hover{background:var(--accent2)}
.play-btn:active{background:var(--accent)}

.rec-wrap{text-align:center;padding:6px 0 2px}
.rec-btn{width:94px;height:94px;border-radius:50%;border:0;background:var(--grad);color:#fff;font-size:31px;
  cursor:pointer;box-shadow:0 8px 22px rgba(15,76,117,.36);position:relative;transition:transform .12s}
.rec-btn:hover{transform:scale(1.03)}
.rec-btn.rec{background:linear-gradient(135deg,#a93226,#c0392b);animation:pulse 1.2s infinite}
.rec-btn:disabled{background:#9aa4b1;box-shadow:none}
.rec-hint{font-size:12.5px;color:var(--sub);margin-top:10px;min-height:18px}

.alt-row{display:flex;gap:8px;margin-top:10px}
.alt-row .btn{flex:1}
.manual{margin-top:10px}
.manual input{margin-bottom:8px}

.result{margin-top:14px;border-radius:13px;padding:14px;display:none;animation:pop .25s ease}
@keyframes pop{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.result.show{display:block}
.result .head{display:flex;align-items:baseline;gap:8px}
.result .big{font-size:36px;font-weight:800;line-height:1}
.result .lv{font-size:12.5px;padding:2px 10px;border-radius:10px;background:rgba(255,255,255,.6);font-weight:700}
.result.lv-perfect{background:#e8f5ee;color:var(--ok)}
.result.lv-great{background:#e8f5ee;color:var(--ok)}
.result.lv-good{background:#eef4fb;color:var(--brand2)}
.result.lv-fair{background:#fdf6e3;color:var(--warn)}
.result.lv-weak{background:#fdecea;color:var(--bad)}
.result.lv-empty{background:#fdecea;color:var(--bad)}
.result .cm{font-size:13.5px;margin-top:8px;line-height:1.7}
.wline{margin-top:10px;font-size:16px;line-height:2.1;font-weight:700}
.wline .ok{color:var(--ok)}
.wline .miss{color:var(--bad);text-decoration:underline wavy var(--bad)}
.wline .sub{color:var(--warn);text-decoration:underline wavy var(--warn)}
.wline .extra{color:var(--sub);text-decoration:line-through}
.wline .sub em,.wline .miss em{font-style:normal;font-size:11px;opacity:.85;display:inline-block;margin-left:2px}
.tips{margin-top:10px;font-size:12.5px;line-height:1.85;background:rgba(255,255,255,.65);border-radius:10px;padding:9px 12px}
.tips b{display:block;margin-bottom:3px}
.tips.corr b{color:var(--bad)}
.playback{margin-top:10px}
.playback audio{width:100%;height:34px}

.banner{border-radius:12px;padding:11px 14px;font-size:12.5px;line-height:1.7;margin-bottom:12px;
  background:#fdf6e3;color:var(--warn);border:1px solid #f0e0bc}
.banner.info{background:var(--accent);color:var(--brand);border-color:#cfe6f2}

/* ===== 教师端数据看板 ===== */
.kpis{display:grid;grid-template-columns:repeat(auto-fill,minmax(128px,1fr));gap:10px;padding:14px 18px}
.kpi{background:var(--accent2);border:1px solid var(--line);border-radius:12px;padding:12px 13px;position:relative;overflow:hidden}
.kpi::before{content:"";position:absolute;left:0;top:0;bottom:0;width:4px;background:var(--brand2);opacity:.75}
.kpi .v{font-size:22px;font-weight:800;color:var(--brand);line-height:1.2}
.kpi .v small{font-size:12px;font-weight:700;color:var(--sub)}
.kpi .k{font-size:11.5px;color:var(--sub);margin-top:2px}
table.grid.tight th,table.grid.tight td{padding:7px 7px;font-size:13px}
.bar-cell{min-width:82px}
.bar-cell .bg{height:7px;background:#e6ecf3;border-radius:4px;overflow:hidden}
.bar-cell .bg > i{display:block;height:100%;background:linear-gradient(90deg,#1976a8,#3ddad7)}
.bar-cell .lb{font-size:11.5px;color:var(--sub);margin-top:2px}
.rowlink{color:var(--brand2);cursor:pointer;font-weight:700;text-decoration:underline}
.rowlink:hover{color:var(--brand)}
.chip{display:inline-block;font-size:11.5px;padding:1px 8px;border-radius:9px;background:var(--bg);color:var(--sub);font-weight:600}
.chip.done{background:#e8f5ee;color:var(--ok)}
.chip.part{background:#fdf6e3;color:var(--warn)}
.chip.none{background:#fdecea;color:var(--bad)}

/* ===== 图表 ===== */
.charts-row{display:flex;gap:14px;margin-bottom:14px;align-items:stretch}
.charts-row .half{flex:1;min-width:0;margin-bottom:0}
.chart{width:100%;height:auto;display:block}
.chart .ct{font-size:12px;fill:var(--ink);font-weight:600}
.chart .cv{font-size:11.5px;fill:var(--sub);font-weight:600}
.legend{display:flex;flex-wrap:wrap;gap:12px;margin-top:8px;font-size:11.5px;color:var(--sub)}
.legend span{display:inline-flex;align-items:center;gap:5px}
.legend i{width:11px;height:11px;border-radius:3px;display:inline-block}
@media (max-width:760px){.charts-row{flex-direction:column}}

/* ===== AI 对话记录（教师端） ===== */
.chat-thread{max-height:56vh;overflow-y:auto;background:var(--accent2);border:1px solid var(--line);
  border-radius:12px;padding:14px}
.bubble{max-width:82%;padding:9px 13px;border-radius:14px;margin-bottom:10px;line-height:1.65;clear:both}
.bubble .bc{white-space:pre-wrap;word-break:break-word;font-size:13.5px}
.bubble .bt{margin-top:4px;font-size:10.5px;opacity:.72}
.bubble.user{background:var(--grad);color:#fff;margin-left:auto;border-bottom-right-radius:4px}
.bubble.assistant{background:#fff;border:1px solid var(--line);margin-right:auto;border-bottom-left-radius:4px}
.bubble.assistant .bt{color:var(--sub)}