/* ============================================================
   Tamil Nadu Class 11 Maths — Animated Slide Engine
   Shared design system + slide deck + game widgets
   ============================================================ */
:root{
  --bg:#0d1320;            /* deep night background */
  --bg2:#121a2c;
  --panel:#172238;
  --panel2:#1d2a45;
  --ink:#eef3fb;           /* main text */
  --muted:#9fb2d0;         /* secondary text */
  --line:#2a3a59;
  --brand:#ffd23f;         /* friendly yellow */
  --brand2:#ff8c42;        /* orange */
  --good:#3ddc97;          /* green */
  --bad:#ff6b6b;           /* red */
  --cool:#6aa6ff;          /* blue */
  --violet:#b78cff;
  --pink:#ff7eb6;
  --teal:#2dd4bf;
  --shadow:0 24px 60px -28px rgba(0,0,0,.8);
  --r:18px;
  --fserif:'Baloo 2','Trebuchet MS',sans-serif;
  --fsans:'Nunito','Segoe UI',system-ui,sans-serif;
  --fmono:'JetBrains Mono',ui-monospace,monospace;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;background:
   radial-gradient(1100px 600px at 12% -8%,rgba(183,140,255,.16),transparent 60%),
   radial-gradient(1100px 600px at 88% -6%,rgba(106,166,255,.16),transparent 60%),
   radial-gradient(900px 500px at 50% 108%,rgba(45,212,191,.12),transparent 60%),
   linear-gradient(170deg,#0d1320,#0a0f1a);
  color:var(--ink);font-family:var(--fsans);line-height:1.6;
  -webkit-font-smoothing:antialiased;min-height:100vh;
}
h1,h2,h3{font-family:var(--fserif);line-height:1.15;font-weight:800}
a{color:var(--cool);text-decoration:none}
.wrap{max-width:1180px;margin:0 auto;padding:0 20px}
.center{text-align:center}
mark{background:linear-gradient(transparent 55%,rgba(255,210,63,.45) 0);color:inherit;padding:0 .1em;border-radius:3px}
.kbd{font-family:var(--fmono);background:#0a1018;border:1px solid var(--line);border-bottom-width:2px;border-radius:6px;padding:1px 7px;font-size:.82em}

/* ===================== LANDING ===================== */
header.hero{position:relative;overflow:hidden;border-bottom:1px solid var(--line);padding:64px 0 48px}
.badge{display:inline-block;letter-spacing:.18em;text-transform:uppercase;font-size:.7rem;font-weight:800;
  color:#0d1320;background:linear-gradient(135deg,var(--brand),var(--brand2));border-radius:999px;padding:6px 16px}
.hero h1{font-size:clamp(2.3rem,6vw,4rem);margin:.25em 0 .12em;
  background:linear-gradient(90deg,#fff,#ffe79a 60%,#ff9d57);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero .lead{color:var(--muted);max-width:62ch;font-size:1.08rem}
.hero .lead b{color:#fff}
.stats{display:flex;gap:10px;flex-wrap:wrap;margin-top:22px;font-size:.86rem}
.stats span{background:rgba(255,255,255,.05);border:1px solid var(--line);border-radius:10px;padding:7px 13px}
.stats span b{color:var(--brand);margin-right:5px;font-size:1.05em}

.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:18px;margin:30px 0 60px}
.card{position:relative;display:flex;flex-direction:column;gap:8px;background:linear-gradient(165deg,var(--panel2),var(--panel));
  border:1px solid var(--line);border-radius:var(--r);padding:20px 20px 18px;transition:.18s;overflow:hidden;text-decoration:none;color:var(--ink)}
.card:hover{transform:translateY(-4px);border-color:var(--brand);box-shadow:var(--shadow)}
.card .num{font-family:var(--fserif);font-size:3.2rem;font-weight:800;line-height:1;opacity:.18;position:absolute;top:6px;right:16px}
.card . chip,.card .tagrow{display:flex;gap:6px;flex-wrap:wrap}
.card h3{margin:.1em 0 .1em;font-size:1.32rem}
.card .desc{color:var(--muted);font-size:.93rem;flex:1}
.card .tag{font-size:.7rem;font-weight:800;letter-spacing:.04em;text-transform:uppercase;padding:3px 9px;border-radius:6px;
  background:rgba(255,255,255,.05);border:1px solid var(--line);color:var(--muted)}
.card .prog{height:8px;border-radius:99px;background:#0a1018;overflow:hidden;margin-top:10px}
.card .prog>i{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--good),var(--teal));transition:width .6s}
.card .meta{display:flex;justify-content:space-between;font-size:.8rem;color:var(--muted);margin-top:6px}
.card .go{align-self:flex-start;margin-top:10px;font-weight:800;color:var(--brand)}
.c1{--ac:#ffd23f}.c2{--ac:#ff8c42}.c3{--ac:#ff7eb6}.c4{--ac:#b78cff}.c5{--ac:#6aa6ff}.c6{--ac:#2dd4bf}
.card .bar{position:absolute;left:0;top:0;bottom:0;width:6px;background:var(--ac)}

/* ===================== SLIDE DECK ===================== */
body.deck{overflow:hidden;height:100vh}
.topbar{position:fixed;top:0;left:0;right:0;height:56px;z-index:50;display:flex;align-items:center;gap:14px;
  padding:0 16px;background:rgba(13,19,32,.86);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.topbar .home{font-weight:800;color:var(--ink);display:flex;align-items:center;gap:8px}
.topbar .home b{color:var(--brand)}
.topbar .ch-title{color:var(--muted);font-size:.92rem;font-weight:700;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.topbar .spacer{flex:1}
.xp-pill{display:flex;align-items:center;gap:7px;background:rgba(255,210,63,.12);border:1px solid rgba(255,210,63,.4);
  color:var(--brand);font-weight:800;border-radius:999px;padding:5px 13px;font-size:.9rem}
.pdf-link{display:inline-flex;align-items:center;gap:5px;font-weight:800;font-size:.82rem;color:var(--cool);
  background:rgba(106,166,255,.12);border:1px solid rgba(106,166,255,.4);border-radius:999px;padding:5px 12px;text-decoration:none;white-space:nowrap}
.pdf-link:hover{background:rgba(106,166,255,.22);color:#cfe0ff}
.hero-pdf{display:inline-flex;align-items:center;gap:8px;font-weight:800;color:#0d1320;text-decoration:none;
  background:linear-gradient(135deg,var(--cool),#9ec3ff);border-radius:999px;padding:10px 20px;box-shadow:var(--shadow)}
.hero-pdf:hover{transform:translateY(-2px)}
.progwrap{position:fixed;top:56px;left:0;right:0;height:5px;background:#0a1018;z-index:50}
.progwrap>i{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--brand),var(--brand2));transition:width .35s}

.stage{position:absolute;top:61px;bottom:64px;left:0;right:0;overflow:hidden}
.slide{position:absolute;inset:0;overflow-y:auto;overflow-x:hidden;padding:28px 20px 40px;
  opacity:0;transform:translateX(40px) scale(.99);pointer-events:none;transition:opacity .4s,transform .4s}
.slide.active{opacity:1;transform:none;pointer-events:auto}
.slide.prev{transform:translateX(-40px) scale(.99)}
.slide-inner{max-width:980px;margin:0 auto}
.slide .eyebrow{display:inline-block;font-size:.72rem;font-weight:800;letter-spacing:.14em;text-transform:uppercase;
  color:#0d1320;background:var(--brand);border-radius:999px;padding:4px 13px;margin-bottom:12px}
.slide.t-concept .eyebrow{background:var(--cool);color:#fff}
.slide.t-example .eyebrow{background:var(--teal);color:#04231e}
.slide.t-problem .eyebrow{background:var(--violet);color:#1a0d2e}
.slide.t-tips .eyebrow{background:var(--brand2);color:#2a1200}
.slide.t-game .eyebrow{background:var(--pink);color:#3a0d24}
.slide h2{font-size:clamp(1.6rem,3.6vw,2.5rem);margin:.1em 0 .35em}
.slide h2 .sec{color:var(--brand);font-family:var(--fmono);font-size:.6em;vertical-align:middle;margin-right:.4em}
.lead-txt{font-size:1.12rem;color:#dfe8f7;max-width:70ch}
.muted{color:var(--muted)}

/* title slide */
.slide.t-title .slide-inner{display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:64vh;text-align:center}
.slide.t-title h1{font-size:clamp(2.2rem,6vw,3.8rem);background:linear-gradient(90deg,#fff,#ffe79a);-webkit-background-clip:text;background-clip:text;color:transparent}
.slide.t-title .big-emoji{font-size:4.5rem;animation:float 3s ease-in-out infinite}
@keyframes float{0%,100%{transform:translateY(0)}50%{transform:translateY(-12px)}}

/* layout helpers */
.two{display:grid;grid-template-columns:1fr 1fr;gap:22px;align-items:start;margin-top:14px}
@media(max-width:780px){.two{grid-template-columns:1fr}}
.panel{background:var(--panel);border:1px solid var(--line);border-radius:14px;padding:16px 18px}
.panel.tight{padding:12px 14px}
.note{border-left:4px solid var(--cool);background:rgba(106,166,255,.08);border-radius:0 12px 12px 0;padding:12px 16px;margin:14px 0}
.note.good{border-color:var(--good);background:rgba(61,220,151,.08)}
.note.warn{border-color:var(--brand2);background:rgba(255,140,66,.09)}
.note.idea{border-color:var(--violet);background:rgba(183,140,255,.09)}
.note .lbl{font-weight:800;font-size:.78rem;letter-spacing:.06em;text-transform:uppercase;display:block;margin-bottom:3px}
ul.clean{list-style:none;padding:0;margin:12px 0}
ul.clean li{position:relative;padding:6px 0 6px 30px}
ul.clean li::before{content:"➜";position:absolute;left:0;color:var(--brand);font-weight:800}
ul.check li::before{content:"✓";color:var(--good)}
.pill-row{display:flex;gap:8px;flex-wrap:wrap;margin:10px 0}
.pill{background:rgba(255,255,255,.05);border:1px solid var(--line);border-radius:999px;padding:5px 13px;font-size:.86rem;font-weight:700}

/* example / problem boxes */
.example-box,.problem-box{border-radius:14px;padding:16px 18px;margin-top:12px}
.example-box{background:rgba(45,212,191,.07);border:1px solid rgba(45,212,191,.35)}
.problem-box{background:rgba(183,140,255,.07);border:1px solid rgba(183,140,255,.35)}
.qn{font-weight:800;font-size:1.05rem;margin-bottom:8px}
.step{margin:8px 0;padding:9px 13px;background:rgba(255,255,255,.04);border:1px solid var(--line);border-radius:10px}
.step .n{display:inline-block;min-width:24px;height:24px;line-height:24px;text-align:center;border-radius:50%;
  background:var(--violet);color:#1a0d2e;font-weight:800;margin-right:8px;font-size:.82rem}
.answer{margin-top:12px;font-weight:800;color:var(--good);background:rgba(61,220,151,.1);border:1px dashed var(--good);
  border-radius:10px;padding:10px 14px}
.reveal-btn{cursor:pointer;background:var(--panel2);border:1px solid var(--line);color:var(--ink);font-weight:800;
  border-radius:10px;padding:8px 16px;font-family:inherit;transition:.15s}
.reveal-btn:hover{border-color:var(--brand);color:var(--brand)}
.hidden{display:none}

/* tips slide */
.tips-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:12px;margin-top:14px}
.tip{background:linear-gradient(165deg,var(--panel2),var(--panel));border:1px solid var(--line);border-radius:14px;padding:14px 16px}
.tip .ic{font-size:1.6rem}
.tip h4{margin:.3em 0 .25em;font-family:var(--fserif);font-size:1.05rem}
.tip p{margin:0;color:var(--muted);font-size:.92rem}

/* canvas / animation */
.canvas-card{background:#0a1018;border:1px solid var(--line);border-radius:14px;padding:10px;position:relative}
.canvas-card canvas{display:block;width:100%;height:auto;border-radius:8px}
.anim-ctrl{display:flex;gap:8px;flex-wrap:wrap;align-items:center;margin-top:10px}
.anim-ctrl button{cursor:pointer;background:var(--panel2);border:1px solid var(--line);color:var(--ink);font-weight:700;
  border-radius:9px;padding:7px 14px;font-family:inherit;transition:.15s}
.anim-ctrl button:hover{border-color:var(--brand);color:var(--brand)}
.anim-ctrl label{font-size:.85rem;color:var(--muted);display:flex;align-items:center;gap:7px}
input[type=range]{accent-color:var(--brand);cursor:pointer}
.readout{font-family:var(--fmono);color:var(--brand);font-weight:700}

/* ===================== GAME WIDGETS ===================== */
.game{background:linear-gradient(165deg,var(--panel2),var(--panel));border:1px solid var(--line);border-radius:16px;padding:18px 20px;margin-top:14px;position:relative}
.game .ghead{display:flex;align-items:center;gap:10px;margin-bottom:6px}
.game .ghead .gtag{font-size:.7rem;font-weight:800;letter-spacing:.08em;text-transform:uppercase;color:#3a0d24;background:var(--pink);border-radius:999px;padding:3px 11px}
.game .ghead .gscore{margin-left:auto;font-weight:800;color:var(--brand)}
.q-text{font-size:1.1rem;font-weight:700;margin:8px 0 12px}
.opts{display:grid;gap:10px}
.opt{cursor:pointer;text-align:left;background:var(--panel);border:1.5px solid var(--line);color:var(--ink);
  border-radius:12px;padding:12px 16px;font-family:inherit;font-size:1rem;font-weight:600;transition:.13s;display:flex;align-items:center;gap:10px}
.opt:hover{border-color:var(--brand);transform:translateX(3px)}
.opt .mk{width:26px;height:26px;flex:none;border-radius:7px;background:rgba(255,255,255,.06);border:1px solid var(--line);
  display:grid;place-items:center;font-weight:800;font-size:.85rem}
.opt.correct{border-color:var(--good);background:rgba(61,220,151,.14)}
.opt.correct .mk{background:var(--good);color:#04231e}
.opt.wrong{border-color:var(--bad);background:rgba(255,107,107,.13)}
.opt.wrong .mk{background:var(--bad);color:#2a0000}
.opt:disabled{cursor:default;opacity:.95}
.fb{margin-top:12px;font-weight:700;border-radius:10px;padding:10px 14px;display:none}
.fb.show{display:block}
.fb.ok{background:rgba(61,220,151,.12);color:var(--good);border:1px solid rgba(61,220,151,.4)}
.fb.no{background:rgba(255,107,107,.12);color:#ffb0b0;border:1px solid rgba(255,107,107,.4)}
.next-q{margin-top:12px}

/* drag & match */
.match-wrap{display:grid;grid-template-columns:1fr 1fr;gap:24px;margin-top:12px}
@media(max-width:620px){.match-wrap{grid-template-columns:1fr}}
.bank,.targets{display:flex;flex-direction:column;gap:10px}
.col-title{font-weight:800;color:var(--muted);font-size:.82rem;text-transform:uppercase;letter-spacing:.06em}
.chip-drag{cursor:grab;background:var(--panel);border:1.5px solid var(--line);border-radius:10px;padding:10px 14px;font-weight:700;transition:.12s;user-select:none}
.chip-drag:active{cursor:grabbing}
.chip-drag.dragging{opacity:.4}
.chip-drag.placed{opacity:.35;pointer-events:none}
.drop{min-height:48px;border:2px dashed var(--line);border-radius:10px;padding:8px 12px;display:flex;align-items:center;gap:10px;transition:.12s}
.drop .prompt{font-weight:700;color:var(--muted)}
.drop.over{border-color:var(--brand);background:rgba(255,210,63,.08)}
.drop.right{border-color:var(--good);border-style:solid;background:rgba(61,220,151,.1)}
.drop.wrong{border-color:var(--bad);background:rgba(255,107,107,.1)}
.drop .slot{margin-left:auto;font-weight:800}

/* sort/order game */
.sortable{display:flex;flex-direction:column;gap:8px;margin-top:10px}
.sort-item{cursor:grab;background:var(--panel);border:1.5px solid var(--line);border-radius:10px;padding:11px 15px;font-weight:700;display:flex;align-items:center;gap:10px}
.sort-item .grip{color:var(--muted)}
.sort-item.dragging{opacity:.4}

/* progress + win */
.gbar{height:8px;border-radius:99px;background:#0a1018;overflow:hidden;margin:12px 0 4px}
.gbar>i{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--pink),var(--violet));transition:width .4s}
.win{text-align:center;padding:18px}
.win .trophy{font-size:3rem;animation:pop .5s}
@keyframes pop{0%{transform:scale(0)}70%{transform:scale(1.2)}100%{transform:scale(1)}}
.stars{font-size:1.8rem;letter-spacing:4px}

/* nav buttons */
.navbar{position:fixed;bottom:0;left:0;right:0;height:64px;z-index:50;display:flex;align-items:center;gap:12px;
  padding:0 16px;background:rgba(13,19,32,.9);backdrop-filter:blur(10px);border-top:1px solid var(--line)}
.nav-btn{cursor:pointer;background:var(--panel2);border:1px solid var(--line);color:var(--ink);font-weight:800;
  border-radius:12px;padding:11px 20px;font-family:inherit;font-size:.96rem;transition:.15s;display:flex;align-items:center;gap:8px}
.nav-btn:hover:not(:disabled){border-color:var(--brand);color:var(--brand);transform:translateY(-2px)}
.nav-btn:disabled{opacity:.35;cursor:default}
.nav-btn.primary{background:linear-gradient(135deg,var(--brand),var(--brand2));color:#1a0d00;border:none}
.navbar .dots{flex:1;display:flex;gap:6px;justify-content:center;flex-wrap:wrap;overflow:hidden;max-height:28px}
.dot{width:9px;height:9px;border-radius:50%;background:var(--line);cursor:pointer;transition:.15s;flex:none}
.dot.active{background:var(--brand);transform:scale(1.4)}
.dot.seen{background:var(--muted)}
.slide-count{font-family:var(--fmono);font-size:.85rem;color:var(--muted);min-width:54px;text-align:center}

/* confetti */
#confetti{position:fixed;inset:0;pointer-events:none;z-index:90}

/* toast */
.toast{position:fixed;bottom:80px;left:50%;transform:translateX(-50%) translateY(20px);opacity:0;
  background:linear-gradient(135deg,var(--good),var(--teal));color:#04231e;font-weight:800;padding:10px 22px;border-radius:999px;
  z-index:80;transition:.3s;box-shadow:var(--shadow)}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

/* math */
mjx-container{color:inherit !important}
.eq{font-family:var(--fmono);background:#0a1018;border:1px solid var(--line);border-radius:8px;padding:2px 8px;color:var(--brand)}
.formula{text-align:center;font-size:1.25rem;background:#0a1018;border:1px solid var(--line);border-radius:12px;padding:14px;margin:12px 0}

@media(max-width:560px){
  .slide{padding:18px 14px 30px}
  .topbar .ch-title{display:none}
  .nav-btn{padding:10px 14px}
}