/* LLM literacy — course site */
:root{
  --bg:#06080d;--bg2:#0b0f18;--fg:#eef1f7;--fg2:#c2c8d4;--mute:#98a1b3;
  --line:rgba(255,255,255,.09);--line2:rgba(255,255,255,.16);--panel:rgba(255,255,255,.035);--panel2:rgba(255,255,255,.06);
  --navbg:rgba(6,8,13,.72);--us1:#633fc4;--us1b:#8b6cf0;--us2:#7378b2;--us3:#83b19f;--s:#8bd450;--o:#f2a541;--r:#ff7b72;
  --r18:18px;--shadow:rgba(0,0,0,.6);--glow:.45;
  --fs-h1:clamp(2.4rem,5.6vw,4.4rem);--fs-h2:clamp(1.7rem,3.1vw,2.4rem);
}
:root[data-theme="light"]{
  --bg:#f6f7fb;--bg2:#ffffff;--fg:#0f1524;--fg2:#2c3446;--mute:#556074;
  --line:rgba(15,23,42,.12);--line2:rgba(15,23,42,.22);--panel:#ffffff;--panel2:#eef1f6;
  --navbg:rgba(246,247,251,.8);--us1:#633fc4;--us1b:#5a37b8;--us2:#5a6099;--us3:#51806e;--s:#4f9a1f;--o:#b55d00;--r:#c2412d;
  --shadow:rgba(15,23,42,.22);--glow:.16;
}
@media (prefers-color-scheme: light){
  :root:not([data-theme="dark"]){
    --bg:#f6f7fb;--bg2:#ffffff;--fg:#0f1524;--fg2:#2c3446;--mute:#556074;
    --line:rgba(15,23,42,.12);--line2:rgba(15,23,42,.22);--panel:#ffffff;--panel2:#eef1f6;
    --navbg:rgba(246,247,251,.8);--us1:#633fc4;--us1b:#5a37b8;--us2:#5a6099;--us3:#51806e;--s:#4f9a1f;--o:#b55d00;--r:#c2412d;
    --shadow:rgba(15,23,42,.22);--glow:.16;
  }
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--fg);font:16px/1.6 "Inter",-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;-webkit-font-smoothing:antialiased;overflow-x:hidden}
a{color:var(--us1b);text-decoration:none}
a:hover{text-decoration:underline}
button{font:inherit;color:inherit}
.wrap{max-width:1280px;margin:0 auto;padding:0 16px}
.mono{font:.86em ui-monospace,SFMono-Regular,Menlo,monospace}
.tag{font-size:.72rem;text-transform:uppercase;letter-spacing:.14em;font-weight:700;color:var(--us1b);margin:0 0 8px;display:block}
.tag.mute{color:var(--mute)}
h1{font-size:var(--fs-h1);line-height:1.02;letter-spacing:-.045em;margin:0 0 20px;font-weight:800}
h2{font-size:var(--fs-h2);line-height:1.1;letter-spacing:-.03em;margin:0 0 10px;font-weight:800}
h3{font-size:1.15rem;margin:0 0 6px;font-weight:700;letter-spacing:-.01em}
p{margin:0 0 12px}
.lead{color:var(--fg2);font-size:1.08rem;max-width:62ch}
.grad{background:linear-gradient(100deg,var(--us1b),var(--us2) 55%,var(--us3));-webkit-background-clip:text;background-clip:text;color:transparent}

/* buttons */
.btn{display:inline-block;padding:12px 22px;border-radius:999px;text-decoration:none;font-weight:600;border:0;cursor:pointer;
  background:linear-gradient(100deg,var(--us1),var(--us2) 55%,var(--us3));color:#fff;box-shadow:0 8px 30px -8px rgba(99,63,196,.7);transition:transform .2s,box-shadow .2s}
.btn:hover{transform:translateY(-1px);text-decoration:none;box-shadow:0 12px 34px -8px rgba(99,63,196,.8)}
.btn.ghost{background:transparent;color:var(--fg);border:1px solid var(--line2);box-shadow:none}
.btn.ghost:hover{border-color:var(--us1b)}
.btn.sm{padding:8px 16px;font-size:.92rem}
.btn[disabled]{opacity:.5;cursor:default;transform:none}
.btn.danger{background:transparent;color:var(--r);border:1px solid var(--line2);box-shadow:none}

/* nav */
.nav{position:sticky;top:0;z-index:20;backdrop-filter:saturate(1.4) blur(14px);-webkit-backdrop-filter:saturate(1.4) blur(14px);background:var(--navbg);border-bottom:1px solid var(--line)}
.navi{display:flex;align-items:center;gap:22px;height:58px}
.brand{font-weight:800;letter-spacing:-.03em;font-size:1.2rem;color:var(--fg)}
.brand b{color:var(--us1b);font-weight:800}
.brand small{display:block;font-size:.66rem;font-weight:600;letter-spacing:.14em;text-transform:uppercase;color:var(--mute);margin-top:-4px}
.navlinks{margin-left:auto;display:flex;gap:18px;align-items:center}
.navlinks a{color:var(--fg2);font-size:.95rem}
.navlinks a:hover{color:var(--fg);text-decoration:none}
.iconbtn{width:36px;height:36px;border-radius:999px;border:1px solid var(--line2);background:transparent;cursor:pointer;display:grid;place-items:center;color:var(--fg2)}
.iconbtn:hover{border-color:var(--us1b);color:var(--fg)}
@media (max-width:720px){.navlinks a.hide-sm{display:none}}

/* hero */
.hero{position:relative;padding:72px 0 40px;overflow:hidden}
.hero::before{content:"";position:absolute;inset:-20% -10% auto -10%;height:70%;background:
  radial-gradient(60% 60% at 15% 30%,rgba(99,63,196,var(--glow)),transparent 70%),
  radial-gradient(40% 50% at 85% 20%,rgba(131,177,159,calc(var(--glow)*.5)),transparent 70%);pointer-events:none;z-index:0}
.hero .wrap{position:relative;z-index:1;display:grid;grid-template-columns:minmax(0,1.1fr) minmax(0,.9fr);gap:40px;align-items:center}
@media (max-width:900px){.hero .wrap{grid-template-columns:1fr}.hero{padding:44px 0 20px}}
.hero .actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:6px}
.glance{background:var(--panel);border:1px solid var(--line);border-radius:var(--r18);padding:22px 24px;backdrop-filter:blur(6px)}
.glance .row{display:grid;grid-template-columns:repeat(2,1fr);gap:16px 20px;margin-top:8px}
.glance .k{font-size:2rem;font-weight:800;letter-spacing:-.03em;line-height:1}
.glance .k small{font-size:.9rem;font-weight:600;color:var(--mute);margin-left:4px}
.glance .l{color:var(--mute);font-size:.86rem;margin-top:4px}
.ring{--p:0;width:92px;height:92px;border-radius:50%;display:grid;place-items:center;
  background:conic-gradient(var(--us1b) calc(var(--p)*1%),var(--line) 0)}
.ring>div{width:74px;height:74px;border-radius:50%;background:var(--bg2);display:grid;place-items:center;font-weight:800;font-size:1.05rem}
.glance .prog{display:flex;align-items:center;gap:18px;margin-top:18px;padding-top:18px;border-top:1px solid var(--line)}

/* sections */
section{padding:56px 0}
.sec-head{display:flex;align-items:end;justify-content:space-between;gap:20px;flex-wrap:wrap;margin-bottom:22px}
.sec-head .lead{margin:0}
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--r18);padding:22px;transition:border-color .2s,transform .2s}
.card.hover:hover{border-color:var(--us1b);transform:translateY(-2px)}
.grid2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}
.grid3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}
.grid4{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px}
@media (max-width:1000px){.grid3,.grid4{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:640px){.grid2,.grid3,.grid4{grid-template-columns:1fr}}

/* outcomes */
.outcome{display:grid;grid-template-columns:44px 1fr;gap:14px;padding:18px 0;border-top:1px solid var(--line)}
.outcome:last-child{border-bottom:1px solid var(--line)}
.outcome .n{font-weight:800;color:var(--us1b);font-size:1.05rem;letter-spacing:-.02em}
.outcome .n small{display:block;color:var(--mute);font-size:.66rem;letter-spacing:.12em;text-transform:uppercase;font-weight:700}
.outcome p{margin:0;color:var(--fg2)}
.outcome a{font-size:.86rem;white-space:nowrap}
.outcomes{columns:2;column-gap:40px}
.outcomes .outcome{break-inside:avoid}
@media (max-width:900px){.outcomes{columns:1}}

/* episode cards */
.ep{display:grid;grid-template-columns:200px 1fr;gap:0;overflow:hidden;padding:0}
.ep .thumb{display:block;position:relative;background:#0B1020;overflow:hidden;min-height:150px}
.ep .thumb img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;display:block;opacity:.92}
.ep .thumb .play{position:absolute;inset:0;display:grid;place-items:center}
.ep .thumb .play span{width:44px;height:44px;border-radius:50%;background:rgba(6,8,13,.72);border:1px solid rgba(255,255,255,.25);display:grid;place-items:center;color:#fff}
.ep .body{padding:16px 18px;display:flex;flex-direction:column;gap:6px;min-width:0}
.ep .meta{display:flex;gap:10px;align-items:center;color:var(--mute);font-size:.8rem;flex-wrap:wrap}
.ep h3{font-size:1.05rem}
.ep h3 a{color:var(--fg)}
.ep .summary{color:var(--fg2);font-size:.9rem;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;margin:0}
.ep .acts{display:flex;gap:8px;margin-top:auto;padding-top:6px;flex-wrap:wrap}
.ep.planned .thumb{display:grid;place-items:center;color:var(--mute);background:var(--panel2)}
.ep.planned .thumb .num{font-size:2rem;font-weight:800;letter-spacing:-.03em;color:var(--mute)}
@media (max-width:640px){.ep{grid-template-columns:1fr}.ep .thumb{aspect-ratio:16/9;min-height:0}}
.chip{display:inline-flex;align-items:center;gap:6px;padding:3px 10px;border-radius:999px;border:1px solid var(--line2);font-size:.74rem;font-weight:600;color:var(--fg2)}
.chip.done{border-color:transparent;background:rgba(139,212,80,.16);color:var(--s)}
.chip.planned{color:var(--mute)}
.chip .dot{width:7px;height:7px;border-radius:50%;background:currentColor}

/* practice types */
.ptype{display:flex;flex-direction:column;gap:10px}
.ptype .ico{width:44px;height:44px;border-radius:12px;background:rgba(99,63,196,.18);display:grid;place-items:center;color:var(--us1b)}
.ptype p{color:var(--fg2);margin:0;font-size:.94rem}

/* footer */
footer{border-top:1px solid var(--line);padding:30px 0 50px;color:var(--mute);font-size:.88rem}
footer .wrap{display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap}

/* episode page */
.crumbs{color:var(--mute);font-size:.88rem;margin:28px 0 10px}
.crumbs a{color:var(--mute)}
.ep-page{display:grid;grid-template-columns:minmax(0,1fr) 340px;gap:28px;align-items:start;padding-bottom:50px}
@media (max-width:960px){.ep-page{grid-template-columns:1fr}}
.player{background:#000;border-radius:var(--r18);overflow:hidden;border:1px solid var(--line);aspect-ratio:16/9}
.player video{width:100%;height:100%;display:block;background:#0B1020}
.player .nope{height:100%;display:grid;place-items:center;color:var(--mute);background:var(--panel2);text-align:center;padding:20px}
.pbar{display:flex;gap:10px;align-items:center;justify-content:space-between;flex-wrap:wrap;margin:14px 0 24px}
.pbar .speed{display:flex;gap:4px}
.pbar .speed button{border:1px solid var(--line2);background:transparent;border-radius:999px;padding:4px 10px;font-size:.8rem;cursor:pointer;color:var(--fg2)}
.pbar .speed button.on{border-color:var(--us1b);color:var(--fg)}
.side .card{margin-bottom:14px}
.terms{display:flex;flex-wrap:wrap;gap:6px;margin-top:6px}
.terms span{border:1px solid var(--line2);border-radius:999px;padding:3px 10px;font-size:.8rem;color:var(--fg2)}
.builds a{display:block;padding:6px 0;border-top:1px solid var(--line);font-size:.92rem}
.builds a:first-child{border-top:0}
.prevnext{display:flex;justify-content:space-between;gap:12px;margin-top:20px}

/* practice page */
.quiz{max-width:860px;margin:0 auto;padding-bottom:60px}
.qhead{display:flex;justify-content:space-between;align-items:center;gap:12px;margin:10px 0 18px}
.qprog{height:6px;background:var(--line);border-radius:3px;overflow:hidden;flex:1}
.qprog i{display:block;height:100%;background:linear-gradient(90deg,var(--us1b),var(--us3));width:0;transition:width .3s}
.q{margin-bottom:16px}
.q .qtype{display:inline-block;font-size:.68rem;letter-spacing:.14em;text-transform:uppercase;font-weight:700;color:var(--mute);margin-bottom:8px}
.q h3{font-size:1.15rem;line-height:1.35;margin-bottom:14px}
.opts{display:grid;gap:8px}
.opt{display:flex;gap:12px;align-items:flex-start;padding:12px 14px;border:1px solid var(--line2);border-radius:12px;background:transparent;cursor:pointer;text-align:left;width:100%;line-height:1.4}
.opt:hover{border-color:var(--us1b)}
.opt .k{width:24px;height:24px;border-radius:50%;border:1px solid var(--line2);display:grid;place-items:center;font-size:.8rem;font-weight:700;flex:none;color:var(--mute)}
.opt.sel{border-color:var(--us1b);background:rgba(99,63,196,.12)}
.opt.sel .k{background:var(--us1);border-color:var(--us1);color:#fff}
.opt.right{border-color:var(--s);background:rgba(139,212,80,.12)}
.opt.wrong{border-color:var(--r);background:rgba(255,123,114,.1)}
.olist{display:grid;gap:8px}
.oitem{display:flex;align-items:center;gap:10px;padding:10px 12px;border:1px solid var(--line2);border-radius:12px;background:var(--panel)}
.oitem .idx{width:26px;height:26px;border-radius:8px;background:var(--panel2);display:grid;place-items:center;font-weight:700;font-size:.8rem;color:var(--mute);flex:none}
.oitem .txt{flex:1;line-height:1.35}
.oitem .mv{display:flex;gap:4px}
.oitem .mv button{width:30px;height:30px;border-radius:8px;border:1px solid var(--line2);background:transparent;cursor:pointer;color:var(--fg2)}
.oitem .mv button:hover{border-color:var(--us1b);color:var(--fg)}
.oitem.right{border-color:var(--s)}
.oitem.wrong{border-color:var(--r)}
.oitem.dragging{opacity:.5}
.hier .oitem{margin-left:calc(var(--d)*26px)}
.hier .oitem .idx{border-radius:50%}
.hier-note{color:var(--mute);font-size:.84rem;margin:0 0 8px}
.qfoot{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-top:16px}
.why{margin-top:12px;padding:12px 14px;border-radius:12px;background:var(--panel2);border-left:3px solid var(--us1b);color:var(--fg2);font-size:.95rem}
.why.ok{border-left-color:var(--s)}
.why.bad{border-left-color:var(--r)}
.score{text-align:center;padding:30px 20px}
.score .big{font-size:3.2rem;font-weight:800;letter-spacing:-.04em;line-height:1}
.score p{color:var(--fg2)}

/* label diagram */
.diagram{border:1px solid var(--line);border-radius:14px;background:#0B1020;padding:8px;margin-bottom:12px}
.diagram svg{width:100%;height:auto;display:block;font-family:Inter,sans-serif}
.diagram .slot rect{fill:rgba(255,255,255,.04);stroke:#8A94A8;stroke-dasharray:6 5;stroke-width:1.5;cursor:pointer;transition:fill .15s}
.diagram .slot:hover rect{fill:rgba(99,63,196,.25)}
.diagram .slot.filled rect{stroke-dasharray:none;stroke:#A78BFA;fill:rgba(167,139,250,.18)}
.diagram .slot.right rect{stroke:#4ADE80;fill:rgba(74,222,128,.16)}
.diagram .slot.wrong rect{stroke:#F87171;fill:rgba(248,113,113,.16)}
.diagram .slot.target rect{stroke:#F5B942;stroke-width:2.5}
.diagram .slot text{fill:#E8ECF5;font-size:13px;font-weight:600;pointer-events:none}
.diagram .slot .hint{fill:#8A94A8;font-weight:500;font-size:11px}
.labels{display:flex;flex-wrap:wrap;gap:8px}
.lab{padding:7px 12px;border-radius:999px;border:1px solid var(--line2);background:var(--panel);cursor:grab;font-size:.9rem;user-select:none}
.lab:hover{border-color:var(--us1b)}
.lab.sel{border-color:var(--us1b);background:rgba(99,63,196,.18)}
.lab.used{opacity:.35;cursor:default}
.lab-help{color:var(--mute);font-size:.84rem;margin:8px 0 0}

/* roadmap of series 2 */
.plan{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:12px}
.plan .card{padding:16px 18px}
.plan .n{color:var(--mute);font-size:.72rem;font-weight:700;letter-spacing:.12em;text-transform:uppercase}
.plan h3{font-size:1rem;margin:4px 0 4px}
.plan p{color:var(--mute);font-size:.86rem;margin:0}

.hidden{display:none !important}
.toast{position:fixed;left:50%;bottom:24px;transform:translateX(-50%);background:var(--bg2);border:1px solid var(--line2);padding:10px 16px;border-radius:999px;box-shadow:0 10px 30px var(--shadow);font-size:.9rem;z-index:50}
@keyframes fadein{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.view{animation:fadein .25s ease-out}