/* 圆锥曲线课件 · 公共样式（沿用概率与数理统计课件配色与组件） */
:root{--paper:#f4f6f3;--ink:#19332e;--muted:#64756e;--line:#dce5df;--green:#126d64;--mint:#e6f4ec;--amber:#9a5907;--gold:#fff0cc;--purple:#7250ac;--lavender:#eee7fb;--blue:#2868b0;--sky:#e5effa;--red:#b8403a;--rose:#fbe9e7;--white:#fff;--shadow:0 8px 28px #153c2910;--fs:15px}
*{box-sizing:border-box}
body{margin:0;background:var(--paper);color:var(--ink);font-family:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;font-size:var(--fs);line-height:1.7}
button,input,select{font:inherit;color:inherit}button{cursor:pointer}button:disabled{opacity:.45;cursor:default}
:focus-visible{outline:3px solid #408ecc;outline-offset:3px}
a{color:var(--green)}
header.top{max-width:1600px;margin:auto;padding:18px 28px 14px;display:flex;justify-content:space-between;align-items:center;gap:16px}
.brand{display:flex;gap:12px;align-items:center;text-decoration:none;color:inherit}
.brandmark{width:44px;height:44px;border-radius:13px;background:var(--green);color:#fff;display:grid;place-items:center;font-family:Georgia,serif;font-size:24px;font-style:italic}
.eyebrow{font-size:10px;letter-spacing:2px;color:var(--green);font-weight:800}
h1{font-size:22px;margin:0;font-weight:760}
header.top p{margin:0;color:var(--muted);font-size:12px}
.top-actions{display:flex;gap:8px;flex-wrap:wrap}
.btn{background:#fff;border:1px solid var(--line);border-radius:9px;padding:7px 13px;font-size:13px;font-weight:650}
.btn:hover{background:#edf4ef;border-color:#9fbeb1}
.btn.primary{background:var(--green);color:#fff;border-color:var(--green)}
.btn.small{padding:4px 10px;font-size:12px}
.layout{max-width:1600px;margin:0 auto;padding:0 28px 40px;display:grid;grid-template-columns:230px minmax(0,1fr);gap:22px}
.sidebar{align-self:start;position:sticky;top:14px;background:#fff;border:1px solid var(--line);border-radius:15px;padding:14px 10px;max-height:calc(100vh - 28px);overflow:auto}
.nav-group h2{font-size:10px;letter-spacing:1.5px;color:var(--muted);margin:14px 8px 6px}
.nav-item{display:flex;gap:8px;align-items:center;border-radius:7px;padding:6px 9px;font-size:13px;color:inherit;text-decoration:none}
.nav-item:hover{background:#f2f6f2}.nav-item.active{background:var(--mint);color:var(--green);font-weight:750}
.nav-item.todo{color:#a3b1aa}.nav-number{font-size:10px;min-width:18px;color:#8b9b92}
main{min-width:0}
.hero{background:#fff;border:1px solid var(--line);border-radius:16px;padding:18px 22px;margin-bottom:16px;box-shadow:var(--shadow)}
.hero h2{margin:0 0 4px;font-size:24px}.hero p{margin:0;color:var(--muted)}
.stepper{display:flex;gap:6px;flex-wrap:wrap;margin:0 0 14px}
.stepper button{border:1px solid var(--line);background:#fff;border-radius:999px;padding:6px 15px;font-size:13px;font-weight:650}
.stepper button.active{background:var(--green);color:#fff;border-color:var(--green)}
.stepper .num{opacity:.6;margin-right:5px;font-variant-numeric:tabular-nums}
.step{display:none}.step.active{display:block;animation:fade .25s}
@keyframes fade{from{opacity:0;transform:translateY(4px)}to{opacity:1}}
.panel{background:#fff;border:1px solid var(--line);border-radius:15px;padding:16px 20px;margin-bottom:16px;box-shadow:var(--shadow)}
.panel h3{margin:0 0 10px;font-size:16px}
.grid2{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr);gap:16px}
.grid2>*{min-width:0}
.grid2>.panel{margin-bottom:0}
.controls{display:flex;flex-wrap:wrap;gap:12px 22px;align-items:center;margin:8px 0}
.controls label{display:flex;gap:8px;align-items:center;font-size:13px;color:var(--muted)}
.controls input[type=range]{width:150px;accent-color:var(--green)}
.controls output{min-width:46px;font-weight:700;color:var(--ink);font-variant-numeric:tabular-nums}
.board{width:100%;aspect-ratio:16/10;border:1px solid var(--line);border-radius:12px;background:#fff}
svg.viz{width:100%;height:auto;display:block}
.katex-display{overflow-x:auto;overflow-y:hidden;padding:2px 0;max-width:100%}
.katex-display>.katex{max-width:100%}
/* 推导：逐行揭示 */
.derive{list-style:none;padding:0;margin:0;counter-reset:d}
.derive li{counter-increment:d;position:relative;padding:8px 12px 8px 44px;border-radius:9px;margin-bottom:4px;transition:opacity .25s,background .25s}
.derive li::before{content:counter(d);position:absolute;left:10px;top:10px;width:22px;height:22px;border-radius:50%;background:var(--mint);color:var(--green);font-size:11px;font-weight:800;display:grid;place-items:center}
.derive li.hidden{opacity:0;pointer-events:none;height:0;padding:0;margin:0;overflow:hidden}
.derive li.current{background:var(--gold)}
.derive .why{display:block;font-size:12.5px;color:var(--muted)}
.derive-bar{display:flex;gap:8px;margin-top:10px;align-items:center}
.derive-bar small{color:var(--muted)}
/* 卡片与提示 */
.callout{border-left:4px solid var(--green);background:var(--mint);padding:10px 14px;border-radius:0 10px 10px 0;margin:10px 0}
.callout.warn{border-color:var(--amber);background:var(--gold)}
.callout.bad{border-color:var(--red);background:var(--rose)}
.callout.idea{border-color:var(--purple);background:var(--lavender)}
.kpis{display:flex;gap:10px;flex-wrap:wrap;margin:8px 0}
.kpi{background:#f7faf7;border:1px solid var(--line);border-radius:10px;padding:6px 12px;min-width:110px}
.kpi small{display:block;color:var(--muted);font-size:11px}.kpi b{font-size:18px;font-variant-numeric:tabular-nums}
.kpi.theory b{color:var(--green)}.kpi.sim b{color:var(--blue)}
table.t{border-collapse:collapse;margin:8px 0;font-variant-numeric:tabular-nums}
table.t th,table.t td{border:1px solid var(--line);padding:5px 12px;text-align:center}
table.t th{background:#f2f6f2;font-weight:700}
/* 例题 */
.problem{border:1px solid var(--line);border-radius:12px;padding:12px 16px;margin:10px 0;background:#fcfdfc}
.problem .src{font-size:11px;color:var(--muted);letter-spacing:1px}
.problem img,.derive figure img{max-width:min(100%,640px);height:auto;border-radius:8px;display:block}
.problem figure img{max-width:min(100%,360px)}
details.sol{margin-top:8px}details.sol summary{cursor:pointer;color:var(--green);font-weight:700}
/* 小测 */
.quiz .opts{display:grid;gap:8px;margin:10px 0}
.quiz .opt{text-align:left;border:1px solid var(--line);background:#fff;border-radius:9px;padding:9px 13px}
.quiz .opt.right{background:var(--mint);border-color:var(--green)}
.quiz .opt.wrong{background:var(--rose);border-color:var(--red)}
.quiz .fb{min-height:24px}
/* 讲台模式（腾讯会议共享屏幕） */
body.stage{--fs:19px}
body.stage .sidebar,body.stage header.top p{display:none}
body.stage .layout{grid-template-columns:1fr;max-width:none}
body.stage .panel h3{font-size:20px}
body.stage .hero h2{font-size:30px}
/* 激光笔 */
#laser{position:fixed;width:18px;height:18px;border-radius:50%;background:radial-gradient(#ff3b30 30%,#ff3b3040 70%);pointer-events:none;z-index:2100;transform:translate(-50%,-50%);display:none}
body.laser-on #laser{display:block}body.laser-on{cursor:none}
/* 批注层：固定覆盖视口，笔迹坐标由 ink.js 随滚动平移；✋/激光模式下不拦截事件 */
#ink-base,#ink-live{position:fixed;left:0;top:0;width:100vw;height:100vh;z-index:1000;pointer-events:none}
body.drawing #ink-live{pointer-events:auto;touch-action:none;cursor:crosshair}
/* 批注工具栏：讲台模式或全屏时显示 */
#ink-toolbar{position:fixed;bottom:20px;left:50%;transform:translateX(-50%);background:rgba(255,255,255,.95);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border:1px solid var(--line);border-radius:12px;padding:8px 14px;box-shadow:0 4px 12px rgba(0,0,0,.15);display:flex;gap:6px;align-items:center;z-index:2000;opacity:0;pointer-events:none;transition:opacity .2s}
body.stage #ink-toolbar,body.fs #ink-toolbar{opacity:1;pointer-events:auto}
#ink-toolbar button{width:36px;height:36px;padding:0;border:1px solid #ddd;border-radius:7px;background:#fff;display:flex;align-items:center;justify-content:center;font-size:18px;line-height:1;transition:background .15s,border-color .15s}
#ink-toolbar button:hover{background:#f5f5f5;border-color:#999}
#ink-toolbar button.on{background:var(--green);color:#fff;border-color:var(--green)}
#ink-toolbar button[data-color]{width:28px;height:28px;border-radius:50%;background:var(--c);border:2px solid #fff;box-shadow:0 0 0 1px #ccc}
#ink-toolbar button[data-color].on{background:var(--c);box-shadow:0 0 0 3px var(--green)}
#ink-toolbar .sep{width:1px;height:24px;background:#ddd;margin:0 4px}
/* 全屏（body.fs 由 shell.js 根据 fullscreenchange 设置）：隐藏顶栏与目录，Esc 退出 */
body.fs header.top,body.fs .sidebar{display:none}
body.fs .layout{grid-template-columns:1fr;max-width:none;padding-top:18px}
body.fs main,body.stage main{padding-bottom:80px}
@media (max-width:1280px){.grid2{grid-template-columns:minmax(0,1fr)}}
@media (max-width:1000px){.layout{grid-template-columns:minmax(0,1fr)}.sidebar{position:static;max-height:none}}
@media (max-width:600px){header.top,.layout{padding-left:14px;padding-right:14px}header.top{flex-direction:column;align-items:flex-start}.panel{padding:12px 14px}.stepper button{padding:5px 11px;font-size:12px}}
/* ===== 圆锥曲线课件补充 ===== */
.board.sq{aspect-ratio:1/1}.board.wide{aspect-ratio:16/9}
.kpi.bad b{color:var(--red)}
.kpi .eq{font-size:12px;color:var(--muted)}
.inv{display:grid;grid-template-columns:auto 1fr 1fr;gap:4px 12px;align-items:center;font-variant-numeric:tabular-nums;margin:8px 0;font-size:14px}
.inv .h{font-size:11px;color:var(--muted);font-weight:700;letter-spacing:1px}
.inv .v{font-weight:700;color:var(--blue)}.inv .th{font-weight:700;color:var(--green)}
.inv .ok{color:var(--green)}.inv .no{color:var(--red)}
.tag{display:inline-block;font-size:11px;font-weight:700;border-radius:6px;padding:0 7px;margin-right:4px;vertical-align:1px}
.tag.E{background:var(--mint);color:var(--green)}.tag.H{background:var(--sky);color:var(--blue)}.tag.P{background:var(--lavender);color:var(--purple)}
table.t.cmp td{text-align:left}
table.t.cmp td:first-child{font-weight:700;background:#f7faf7}
.sol-tabs{display:flex;gap:6px;flex-wrap:wrap;margin:6px 0}
.sol-tabs .btn.on{background:var(--purple);color:#fff;border-color:var(--purple)}
.sol-tabs small{color:var(--muted);margin-left:4px}
.problem table{border-collapse:collapse;margin:8px 0}.problem td,.problem th{border:1px solid var(--line);padding:4px 10px}
body.stage .inv{font-size:17px}
body[data-nosidebar] main{display:block;max-width:1600px;margin:0 auto;padding:0 28px 40px}
.problem .stem img.pimg,.derive img.pimg,.callout img.pimg{max-width:min(100%,360px);height:auto;display:block;margin:8px 0;border-radius:8px}
.cut{color:var(--red);font-size:12px}
.span-li,.li{display:block;padding-left:1em;text-indent:-1em}.li::before{content:'• ';color:var(--muted)}
.lib-filter{display:flex;gap:8px;flex-wrap:wrap;align-items:center;margin-bottom:10px}
.lib-list{display:flex;flex-wrap:wrap;gap:6px;max-height:180px;overflow:auto;margin-bottom:12px}
.lib-list .btn.on{background:var(--green);color:#fff;border-color:var(--green)}
.sol-tabs .btn.on small{color:#fff;opacity:.85}
.concl{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:10px}
.ccard{border:1px solid var(--line);border-radius:11px;padding:9px 13px;background:#fff}
.ccard-h{display:flex;gap:6px;align-items:center;flex-wrap:wrap;font-size:13.5px}.ccard-h small{color:var(--muted);font-size:11px}
.vok{margin-left:auto;font-size:11px;color:var(--green);font-weight:700}
.ccard-f{font-size:15px}.ccard-n{font-size:12.5px;color:var(--muted)}.ccard-n.fix{color:var(--amber)}
.big-formula{font-size:20px;padding:6px 0}
.legend{display:flex;gap:14px;flex-wrap:wrap;font-size:12px;color:var(--muted);margin-top:6px}
.legend i{display:inline-block;width:14px;height:3px;border-radius:2px;margin-right:5px;vertical-align:3px}