:root{
  --bg:#F7FAFC; --card:#FFFFFF; --primary:#4A90D9; --primary-dark:#3579BE;
  --teal:#3BB99B; --orange:#F5A623; --ok:#52C41A; --err:#F5222D;
  --text:#2C3E50; --text-2:#6B7A8A; --line:#E5ECF2;
  --r:14px; --shadow:0 2px 10px rgba(74,144,217,.08);
}
*{margin:0;padding:0;box-sizing:border-box;-webkit-tap-highlight-color:transparent}
body{font-family:-apple-system,"PingFang SC","Microsoft YaHei",sans-serif;background:var(--bg);color:var(--text);font-size:15px;line-height:1.6;padding-bottom:70px}
button{font-family:inherit;border:none;background:none;cursor:pointer;color:inherit}
#app{max-width:520px;margin:0 auto;padding:14px 14px 20px;min-height:calc(100vh - 70px)}

/* ---------- 底部导航 ---------- */
#tabbar{position:fixed;bottom:0;left:0;right:0;max-width:520px;margin:0 auto;background:#fff;border-top:1px solid var(--line);display:flex;z-index:50}
.tab{flex:1;padding:7px 0 9px;display:flex;flex-direction:column;align-items:center;gap:1px;font-size:11px;color:var(--text-2)}
.tab-icon{font-size:21px}
.tab.active{color:var(--primary);font-weight:600}

/* ---------- 通用 ---------- */
.card{background:var(--card);border-radius:var(--r);box-shadow:var(--shadow);padding:14px;margin-bottom:12px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:11px 18px;border-radius:12px;font-size:15px;font-weight:600;transition:transform .1s}
.btn:active{transform:scale(.96)}
.btn-primary{background:var(--primary);color:#fff}
.btn-teal{background:var(--teal);color:#fff}
.btn-orange{background:var(--orange);color:#fff}
.btn-ghost{background:#EEF4FA;color:var(--primary)}
.btn-danger{background:#FDECEC;color:var(--err)}
.btn-block{display:flex;width:100%}
.btn-sm{padding:7px 13px;font-size:13px;border-radius:9px}
.tag{display:inline-block;padding:2px 9px;border-radius:20px;font-size:11px;background:#EEF4FA;color:var(--primary);margin:2px 3px 2px 0}
.tag-gray{background:#F0F3F6;color:var(--text-2)}
.tag-orange{background:#FEF4E3;color:#D48806}
.page-title{font-size:19px;font-weight:700;margin:4px 0 12px}
.back-btn{width:30px;height:30px;min-width:30px;border-radius:50%;border:1px solid var(--line);background:#fff;color:var(--primary);font-size:15px;font-weight:700;line-height:1;display:inline-flex;align-items:center;justify-content:center;padding:0;margin-right:6px;vertical-align:middle}
.back-btn:active{background:#EEF4FA;transform:scale(.92)}
.muted{color:var(--text-2);font-size:13px}
.hr{height:1px;background:var(--line);margin:12px 0}
.hidden{display:none!important}

/* ---------- 首页 ---------- */
.hero{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px}
.hero h1{font-size:20px}
.streak-pill{background:linear-gradient(135deg,#FF8A4C,#F5A623);color:#fff;border-radius:20px;padding:5px 13px;font-size:13px;font-weight:600;box-shadow:0 2px 8px rgba(245,166,35,.3)}
.quick-row{display:flex;gap:10px;margin-bottom:14px}
.quick-btn{flex:1;background:#fff;border-radius:var(--r);box-shadow:var(--shadow);padding:12px 6px;text-align:center;font-size:12px;color:var(--text)}
.quick-btn .qi{font-size:24px;display:block;margin-bottom:3px}
.graph-card{padding:10px 6px 4px}
.graph-title{font-size:15px;font-weight:700;padding:6px 10px 0}
.graph-hint{padding:0 10px 6px;font-size:11px;color:var(--text-2)}
.node{cursor:pointer}
.node circle{transition:stroke-width .15s}
.node.selected circle{stroke-width:4}
.ch-card{display:flex;align-items:center;gap:12px;background:#fff;border-radius:var(--r);box-shadow:var(--shadow);padding:13px 14px;margin-bottom:10px}
.ch-icon{width:44px;height:44px;border-radius:12px;display:flex;align-items:center;justify-content:center;color:#fff;font-weight:700;font-size:17px;flex-shrink:0}
.ch-info{flex:1;min-width:0}
.ch-info h3{font-size:15px;margin-bottom:1px}
.ch-bar{height:6px;background:#EDF2F7;border-radius:3px;margin:6px 0 4px;overflow:hidden}
.ch-bar i{display:block;height:100%;border-radius:3px;background:var(--teal);transition:width .5s}

/* ---------- 抽屉 ---------- */
.drawer-mask{position:fixed;inset:0;background:rgba(0,0,0,.35);z-index:80;opacity:1;transition:opacity .2s}
.drawer{position:fixed;bottom:0;left:0;right:0;max-width:520px;margin:0 auto;background:#fff;border-radius:20px 20px 0 0;padding:18px 18px 26px;z-index:90;transform:translateY(0);transition:transform .25s;max-height:65vh;overflow-y:auto}
.drawer.down{transform:translateY(110%)}
.drawer h3{font-size:17px;margin-bottom:6px}

/* ---------- 学习 ---------- */
.bread{font-size:12px;color:var(--text-2);margin-bottom:8px}
.bread b{color:var(--primary)}
.sec-group{margin-bottom:12px}
.sec-head{font-size:14px;font-weight:700;color:var(--primary-dark);padding:4px 2px}
.topic-item{display:flex;align-items:center;gap:10px;background:#fff;border-radius:12px;box-shadow:var(--shadow);padding:12px 13px;margin-bottom:8px}
.topic-item .t-dot{width:9px;height:9px;border-radius:50%;flex-shrink:0}
.topic-item h4{font-size:14.5px;flex:1}
.st-badge{font-size:11px;padding:2px 8px;border-radius:10px;background:#F0F3F6;color:var(--text-2);flex-shrink:0}
.st-visited{background:#E7F1FB;color:var(--primary)}
.st-practiced{background:#FFF6E5;color:#D48806}
.st-mastered{background:#E8F7F1;color:#1D9E7C}
.kp-def{background:#EEF6FE;border-left:4px solid var(--primary);border-radius:8px;padding:10px 12px;margin:10px 0;font-size:14.5px}
.kp-rule{background:#EAF9F4;border-left:4px solid var(--teal);border-radius:8px;padding:10px 12px;margin:10px 0;font-size:14.5px}
.kp-warn{background:#FFF1F0;border-left:4px solid var(--err);border-radius:8px;padding:10px 12px;margin:10px 0;font-size:14px}
.kp-warn b{color:var(--err)}
.kp-note{background:#FFF9EC;border-left:4px solid var(--orange);border-radius:8px;padding:10px 12px;margin:10px 0;font-size:14px}
.ex-card{border:1px solid var(--line);border-radius:10px;padding:11px 12px;margin:9px 0;font-size:14px}
.ex-steps{background:#F8FAFC;border-radius:8px;padding:9px 11px;margin-top:8px;font-size:13.5px}
.ex-steps li{margin-left:16px;margin-bottom:3px}
.topic-foot{display:flex;gap:8px;margin:16px 0 8px}
.topic-foot .btn{flex:1;padding:11px 4px;font-size:14px}
.model-box{background:#FDFEFF;border:1px solid #DCEAF7;border-radius:12px;padding:12px;margin:10px 0}
.model-title{font-size:13px;font-weight:700;color:var(--primary);margin-bottom:6px}
.model-readout{display:flex;gap:8px;justify-content:center;margin:8px 0}
.readout-chip{background:#EEF4FA;border-radius:9px;padding:5px 12px;font-size:14px;font-weight:700;color:var(--primary-dark)}
.slider-row{display:flex;align-items:center;gap:10px;margin-top:8px}
.slider-row input[type=range]{flex:1;accent-color:var(--primary)}
.chip-select{display:inline-block;padding:8px 13px;border-radius:10px;background:#F0F5FA;border:2px solid transparent;margin:4px;font-size:14.5px;font-weight:600}
.chip-select.sel{border-color:var(--primary);background:#E3F0FC}
.drop-box{min-height:52px;border:2px dashed #B9CFE4;border-radius:10px;padding:6px;margin:7px 0;display:flex;flex-wrap:wrap;gap:4px;align-items:center}
.drop-box.full{border-color:var(--teal)}
.drop-chip{background:#fff;border:1px solid var(--line);border-radius:8px;padding:3px 9px;font-size:14px;font-weight:600;box-shadow:0 1px 3px rgba(0,0,0,.06)}
.shake{animation:shake .35s}
@keyframes shake{25%{transform:translateX(-5px)}50%{transform:translateX(5px)}75%{transform:translateX(-3px)}}
.model-msg{text-align:center;font-size:13px;margin-top:6px;min-height:18px;color:var(--teal);font-weight:600}

/* ---------- 历史故事 / 数学家名片 / 应用方向 ---------- */
.hist-card{background:linear-gradient(135deg,#FFF9EC,#FFF4E0);border:1px solid #F2E1BD;border-radius:12px;padding:13px;margin:12px 0}
.hist-title{font-size:13px;font-weight:700;color:#B8860B;margin-bottom:8px}
.math-card{display:flex;align-items:center;gap:11px;background:#fff;border-radius:10px;padding:10px 12px;box-shadow:0 1px 4px rgba(184,134,11,.12)}
.math-badge{width:44px;height:44px;border-radius:50%;background:linear-gradient(135deg,#F5A623,#E4626F);color:#fff;display:flex;align-items:center;justify-content:center;font-size:20px;font-weight:800;flex-shrink:0}
.apps-card{background:#EEF6FE;border:1px solid #D5E7F8;border-radius:12px;padding:13px;margin:12px 0}
.apps-card .hist-title{color:var(--primary-dark)}
.apps-chips{display:flex;flex-wrap:wrap;gap:7px}
.app-chip{background:#fff;border:1px solid #CBE1F5;border-radius:20px;padding:5px 11px;font-size:12.5px;color:#2C5A88}

/* ---------- 单元易错点专区 ---------- */
.um-card{border:1px solid #FFD9D5;background:#FFF7F6}
.um-head{display:flex;justify-content:space-between;align-items:center;padding:2px 0;cursor:pointer}
.um-head b{color:var(--err);font-size:14.5px}
.um-item{border-bottom:1px dashed #FFD9D5;padding:10px 2px}
.um-item:last-child{border:none;padding-bottom:2px}
.um-t{font-weight:700;font-size:13.5px;color:var(--err)}
.um-e{font-size:13px;color:var(--text);margin-top:3px;line-height:1.65}

/* ---------- 练习 ---------- */
.opt-btn{display:block;width:100%;text-align:left;background:#fff;border:2px solid var(--line);border-radius:12px;padding:12px 14px;font-size:15px;margin-bottom:9px;transition:all .15s}
.opt-btn.sel{border-color:var(--primary);background:#EAF3FC}
.opt-btn.right{border-color:var(--ok);background:#F0FBEB;font-weight:700}
.opt-btn.wrong{border-color:var(--err);background:#FFF1F0}
.opt-key{display:inline-flex;width:24px;height:24px;border-radius:50%;background:#F0F5FA;color:var(--primary);align-items:center;justify-content:center;font-size:13px;font-weight:700;margin-right:8px}
.q-stem{font-size:16px;font-weight:600;line-height:1.7;margin:6px 0 14px}
.judge-row{display:flex;gap:12px}
.judge-row .btn{flex:1;padding:14px}
.fill-input{width:100%;padding:12px 14px;border:2px solid var(--line);border-radius:12px;font-size:17px;text-align:center;font-family:inherit}
.fill-input:focus{outline:none;border-color:var(--primary)}
.prog-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:4px}
.prog-bar{height:7px;background:#EDF2F7;border-radius:4px;overflow:hidden;margin-bottom:14px}
.prog-bar i{display:block;height:100%;background:linear-gradient(90deg,var(--primary),var(--teal));border-radius:4px;transition:width .3s}
.feedback{border-radius:12px;padding:13px;margin:10px 0;animation:pop .25s}
@keyframes pop{from{transform:scale(.94);opacity:0}to{transform:scale(1);opacity:1}}
.fb-ok{background:#F0FBEB;border:1px solid #C7E8B4}
.fb-wrong{background:#FFF1F0;border:1px solid #FFC7C2}
.fb-head{font-weight:700;font-size:15px;margin-bottom:6px}
.fb-ok .fb-head{color:var(--ok)} .fb-wrong .fb-head{color:var(--err)}
.src-link{display:inline-flex;align-items:center;gap:5px;background:#EEF4FA;color:var(--primary);font-size:13px;font-weight:600;border-radius:9px;padding:7px 12px;margin-top:8px}
.filter-chips{display:flex;flex-wrap:wrap;gap:7px;margin:8px 0 14px}
.f-chip{padding:7px 14px;border-radius:20px;background:#fff;border:1.5px solid var(--line);font-size:13px;color:var(--text-2)}
.f-chip.on{background:var(--primary);border-color:var(--primary);color:#fff;font-weight:600}
.timer-pill{background:#FFF3E8;color:#D46B08;font-weight:700;border-radius:20px;padding:4px 13px;font-size:14px}
.timer-pill.danger{background:#FDECEC;color:var(--err);animation:blink 1s infinite}
@keyframes blink{50%{opacity:.55}}
.result-hero{text-align:center;padding:22px 0 12px}
.score-ring{font-size:40px;font-weight:800;color:var(--primary)}
.stat-grid{display:grid;grid-template-columns:1fr 1fr 1fr;gap:8px;margin:14px 0}
.stat-cell{background:#F8FBFE;border-radius:10px;padding:10px 4px;text-align:center}
.stat-cell b{font-size:18px;color:var(--primary-dark)}
.stat-cell span{display:block;font-size:11px;color:var(--text-2)}
.rev-item{border:1px solid var(--line);border-radius:10px;padding:10px 12px;margin-bottom:8px;font-size:13.5px}

/* ---------- 管理 ---------- */
.ring-wrap{display:flex;align-items:center;gap:16px}
.cal{display:grid;grid-template-columns:repeat(7,1fr);gap:4px;margin-top:8px}
.cal .cw{text-align:center;font-size:10px;color:var(--text-2)}
.cal .cd{aspect-ratio:1;display:flex;align-items:center;justify-content:center;border-radius:8px;font-size:12px;background:#F2F6FA;color:var(--text-2)}
.cal .cd.on{background:var(--teal);color:#fff;font-weight:700}
.cal .cd.today{border:2px solid var(--orange)}
.weak-item{display:flex;align-items:center;gap:9px;padding:9px 2px;border-bottom:1px solid var(--line);font-size:14px}
.weak-item:last-child{border:none}
.mist-item{display:flex;gap:10px;align-items:flex-start;border-bottom:1px solid var(--line);padding:11px 2px;font-size:14px}
.mist-item:last-child{border:none}

/* ---------- 抽屉/toast ---------- */
#toast{position:fixed;bottom:90px;left:50%;transform:translateX(-50%) translateY(20px);background:rgba(44,62,80,.92);color:#fff;padding:9px 18px;border-radius:20px;font-size:13.5px;opacity:0;transition:all .25s;z-index:99;pointer-events:none;max-width:80vw;text-align:center}
#toast.show{opacity:1;transform:translateX(-50%) translateY(0)}
.guide-overlay{position:fixed;inset:0;background:rgba(20,40,60,.55);z-index:100;display:flex;align-items:flex-end;justify-content:center}
.guide-card{background:#fff;border-radius:20px 20px 0 0;max-width:520px;width:100%;padding:22px 20px 30px}
.guide-card h3{margin-bottom:10px}
.guide-step{display:flex;gap:10px;margin-bottom:11px;font-size:14px}
.guide-step .gi{font-size:22px}
svg text{font-family:inherit}
@media(min-width:520px){body{background:#EDF2F7}#app,#tabbar,.drawer,.guide-card{box-shadow:0 0 30px rgba(0,0,0,.06)}}