/* ---------- base (shared) ---------- */
:root{--navy:#0B1A3A;--indigo:#24398C;--saffron:#F6A21E;--ivory:#F8F6F1;--ease:cubic-bezier(.22,1,.36,1);--radius:18px;--wrap:1160px}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;overflow-x:clip}
body{margin:0;font-family:"Sora",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;background:var(--bg);color:var(--fg);line-height:1.6;font-size:16px;overflow-x:clip;-webkit-font-smoothing:antialiased}
img,svg{max-width:100%;display:block}
a{color:inherit}
h1,h2,h3{line-height:1.12;margin:0;letter-spacing:-.02em}
p{margin:0}
ul,ol{margin:0;padding:0;list-style:none}
button{font:inherit;color:inherit}
.wrap{width:min(100% - 40px,var(--wrap));margin-inline:auto}
.skip{position:absolute;left:12px;top:-60px;z-index:100;background:var(--saffron);color:var(--navy);padding:10px 14px;border-radius:10px;font-weight:700;text-decoration:none}
.skip:focus{top:12px}
:focus-visible{outline:3px solid var(--focus,var(--saffron));outline-offset:3px;border-radius:6px}
.section{padding:clamp(72px,10vw,128px) 0;position:relative}
.kicker{font-size:.78rem;font-weight:700;letter-spacing:.16em;text-transform:uppercase;color:var(--kicker,var(--saffron));margin-bottom:14px}
.h2{font-size:clamp(1.9rem,5.4vw,3.2rem);font-weight:800;max-width:18ch}
.lead{margin-top:16px;max-width:56ch;color:var(--muted);font-size:clamp(1rem,2.4vw,1.12rem)}
/* header */
.site-header{position:sticky;top:0;z-index:50}
.nav-row{display:flex;align-items:center;gap:20px;height:68px}
.brand img{height:34px;width:auto}
.nav{display:flex;gap:26px;margin-left:auto;font-size:.92rem;font-weight:600}
.nav a{text-decoration:none;opacity:.82;transition:opacity .2s}
.nav a:hover{opacity:1}
.menu-btn{display:none;background:none;border:0;width:44px;height:44px;position:relative;cursor:pointer;margin-right:-8px}
.menu-btn span{position:absolute;left:11px;right:11px;height:2px;background:currentColor;border-radius:2px;transition:transform .3s var(--ease)}
.menu-btn span:first-child{top:17px}.menu-btn span:last-child{top:25px}
.menu-btn[aria-expanded=true] span:first-child{transform:translateY(4px) rotate(45deg)}
.menu-btn[aria-expanded=true] span:last-child{transform:translateY(-4px) rotate(-45deg)}
/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:9px;min-height:48px;padding:0 22px;border-radius:999px;font-weight:700;font-size:.95rem;text-decoration:none;border:0;cursor:pointer;transition:transform .35s var(--ease),box-shadow .35s var(--ease),background .25s,color .25s;white-space:nowrap}
.btn:active{transform:scale(.97)}
.btn-sm{min-height:42px;padding:0 16px;font-size:.88rem}
.btn-nav{min-height:40px;padding:0 16px;font-size:.85rem}
/* video */
.chapter-media{position:relative;aspect-ratio:16/9;overflow:hidden;background:#000}
.yt-lite,.yt-soon{position:absolute;inset:0;border:0;padding:0;margin:0;background:none;cursor:pointer;display:block;width:100%}
.yt-soon{cursor:default}
.yt-lite img,.yt-soon img{width:100%;height:100%;object-fit:cover;transition:transform .8s var(--ease),filter .5s}
.yt-soon img{filter:saturate(.7) brightness(.62)}
.yt-play{position:absolute;left:50%;top:50%;width:64px;height:64px;margin:-32px 0 0 -32px;border-radius:50%;display:grid;place-items:center;background:var(--saffron);color:var(--navy);box-shadow:0 10px 30px rgba(0,0,0,.35);transition:transform .4s var(--ease)}
.yt-play svg{width:26px;height:26px;margin-left:3px}
.yt-lite:hover img{transform:scale(1.04)}
.yt-lite:hover .yt-play{transform:scale(1.1)}
.soon-badge{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);background:rgba(11,26,58,.85);color:#fff;border:1px solid rgba(246,162,30,.7);padding:9px 16px;border-radius:999px;font-weight:700;font-size:.85rem;white-space:nowrap;backdrop-filter:blur(6px)}
.yt-frame{position:absolute;inset:0;width:100%;height:100%;border:0}
.chapter-actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:20px}
.chapter-topics{display:flex;flex-wrap:wrap;gap:6px;margin-top:14px}
.chapter-meta{display:flex;justify-content:space-between;gap:10px;font-size:.8rem;font-weight:600;color:var(--muted);margin-bottom:8px}
.chapter-title{font-size:1.35rem;font-weight:800}
/* notes */
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:28px 0 18px}
.chip{min-height:40px;padding:0 16px;border-radius:999px;cursor:pointer;font-weight:600;font-size:.88rem}
.notes{display:grid;gap:12px}
.note{display:flex;align-items:center;gap:14px;padding:14px 14px 14px 16px}
.note-icon{flex:none;width:46px;height:46px;border-radius:12px;display:grid;place-items:center;font-size:.72rem;font-weight:800;letter-spacing:.06em}
.note-text{flex:1;min-width:0;display:flex;flex-direction:column}
.note-text strong{font-size:.98rem;line-height:1.3}
.note-text span{font-size:.82rem;color:var(--muted)}
.note-empty{justify-content:center;color:var(--muted);text-align:center;padding:22px}
/* social */
.social{display:flex;flex-wrap:wrap;gap:12px}
.social a{display:flex;align-items:center;gap:12px;text-decoration:none;padding:12px 18px 12px 14px;border-radius:16px;transition:transform .35s var(--ease)}
.social a:hover{transform:translateY(-3px)}
.social span{display:flex;flex-direction:column;line-height:1.25}
.social small{font-size:.8rem;opacity:.75}
/* footer */
.site-footer{padding:56px 0 28px}
.foot-grid{display:flex;flex-wrap:wrap;justify-content:space-between;gap:28px}
.foot-grid img{height:32px;width:auto}
.foot-tag{margin-top:10px;font-size:.9rem;color:var(--muted)}
.site-footer nav{display:flex;flex-wrap:wrap;gap:10px 22px;font-size:.9rem;font-weight:600}
.site-footer nav a{text-decoration:none;opacity:.85}
.site-footer nav a:hover{opacity:1;text-decoration:underline}
.foot-base{margin-top:36px;padding-top:20px;border-top:1px solid var(--line);display:flex;flex-wrap:wrap;justify-content:space-between;gap:8px;font-size:.78rem;color:var(--muted)}
/* reveal base */
.reveal{opacity:0;transform:translateY(26px);transition:opacity .9s var(--ease),transform .9s var(--ease);transition-delay:calc(var(--i,0) * 90ms)}
.reveal.in{opacity:1;transform:none}
html:not(.ready) .reveal{opacity:1;transform:none}
@media (max-width:860px){
  .menu-btn{display:block}
  .btn-nav{margin-left:auto}
  .nav{position:fixed;inset:68px 0 auto 0;flex-direction:column;gap:0;padding:8px 20px 20px;background:var(--menu-bg,var(--bg));border-bottom:1px solid var(--line);transform:translateY(-12px);opacity:0;pointer-events:none;transition:opacity .3s var(--ease),transform .3s var(--ease)}
  .nav a{padding:14px 0;border-bottom:1px solid var(--line);font-size:1.05rem;opacity:1}
  .menu-open .nav{opacity:1;transform:none;pointer-events:auto}
}
@media (max-width:520px){.note{flex-wrap:wrap}.note .btn{flex-basis:100%}}
@media (max-width:420px){.btn-nav span{display:none}.btn-nav{padding:0 12px;width:44px;height:44px;min-height:44px}}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important;transition-delay:0ms!important}
  .reveal{opacity:1!important;transform:none!important}
}

/* ===== Design 3 · Sticker ===== */
.d3{--bg:#FBF7EE;--fg:#0B1A3A;--muted:#4A5575;--line:#0B1A3A;--kicker:#24398C;--focus:#24398C;--ink:#0B1A3A;--mint:#9BE7C9;--pink:#FFB3C7;--sky:#B9C8FF;--radius:22px;--menu-bg:#FBF7EE;
  background-color:var(--bg);background-image:radial-gradient(rgba(11,26,58,.13) 1.2px,transparent 1.2px);background-size:22px 22px}
.d3 .site-header{background:var(--bg);border-bottom:3px solid var(--ink)}
.d3 .nav a{font-weight:700}
.d3 .nav a:hover{text-decoration:underline wavy var(--saffron) 2px;text-underline-offset:6px}
.btn{border:3px solid var(--ink);box-shadow:4px 4px 0 var(--ink);border-radius:16px;font-weight:800}
.btn:hover{transform:translate(-2px,-2px) rotate(-1deg);box-shadow:6px 6px 0 var(--ink)}
.btn:active{transform:translate(3px,3px);box-shadow:1px 1px 0 var(--ink)}
.btn-chunky{min-height:56px;padding:0 24px;font-size:1rem}
.btn-yt{background:var(--saffron);color:var(--ink)}
.btn-alt{background:#fff;color:var(--ink)}
.btn-pdf{background:var(--saffron);color:var(--ink)}
.btn-ghost{background:#fff;color:var(--ink)}
.btn-nav{background:var(--mint);color:var(--ink);box-shadow:3px 3px 0 var(--ink)}
@media (max-width:420px){.btn-nav{border-width:2px}}
/* hero */
.hero{padding:clamp(36px,7vw,80px) 0 clamp(40px,6vw,70px);overflow:hidden}
.hero-grid{display:grid;grid-template-columns:1.1fr .9fr;gap:30px;align-items:center}
.tag{display:inline-block;background:var(--sky);border:3px solid var(--ink);border-radius:999px;padding:6px 14px;font-weight:800;font-size:.82rem;box-shadow:3px 3px 0 var(--ink);transform:rotate(-2deg)}
.hero-h{font-size:clamp(2.8rem,10vw,5.6rem);font-weight:800;letter-spacing:-.04em;line-height:1;margin-top:22px}
.hero-h>span{display:inline-block}
.hl{background:var(--saffron);border:3px solid var(--ink);border-radius:18px;padding:.02em .22em .1em;box-shadow:6px 6px 0 var(--ink);margin-top:.12em}
.hero-sub{margin-top:22px;max-width:48ch;font-size:clamp(1rem,2.5vw,1.13rem);color:var(--muted);font-weight:600}
.hero-cta{display:flex;flex-wrap:wrap;gap:14px;margin-top:28px}
.pop{opacity:0;transform:scale(.6) rotate(var(--r,-4deg));animation:popIn .7s cubic-bezier(.34,1.56,.64,1) forwards;animation-delay:calc(var(--d) * 90ms + 80ms)}
.hl.pop{--r:-3deg}
@keyframes popIn{to{opacity:1;transform:rotate(var(--rr,0deg))}}
.hl.pop{--rr:-2deg}
.tag.pop{--rr:-2deg}
.sticker-board{position:relative;height:clamp(340px,44vw,520px)}
.stick{opacity:0;transform:scale(.4) rotate(calc(var(--r) * 3));animation:stickOn .8s cubic-bezier(.34,1.56,.64,1) forwards,wobble 5s ease-in-out infinite;animation-delay:calc(var(--d) * 110ms + 200ms),calc(var(--d) * 110ms + 1100ms)}
@keyframes stickOn{to{opacity:1;transform:rotate(var(--r))}}
@keyframes wobble{0%,100%{transform:rotate(var(--r)) translateY(0)}50%{transform:rotate(calc(var(--r) * -.4)) translateY(-8px)}}
/* marquee */
.marquee{background:var(--ink);color:var(--saffron);border-block:3px solid var(--ink);overflow:hidden;transform:rotate(-1.2deg);margin:10px -10px 0;padding:14px 0}
.marquee-track{display:flex;gap:28px;width:max-content;animation:marq 22s linear infinite;font-weight:800;font-size:clamp(1.1rem,3vw,1.6rem);text-transform:uppercase;letter-spacing:.02em;white-space:nowrap}
.marquee i{font-style:normal;color:#fff}
@keyframes marq{to{transform:translateX(-50%)}}
/* reveal: pop */
.reveal{transform:translateY(30px) rotate(var(--tilt,-1.5deg)) scale(.96);transition:opacity .7s var(--ease),transform .8s cubic-bezier(.34,1.56,.64,1)}
.reveal.in{transform:rotate(var(--rest,0deg))}
.h2{font-size:clamp(2rem,6vw,3.4rem)}
.kicker{display:inline-block;background:#fff;border:2.5px solid var(--ink);border-radius:999px;padding:4px 12px;letter-spacing:.08em;color:var(--ink);box-shadow:3px 3px 0 var(--ink)}
/* subjects */
.subjects{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:18px;margin-top:40px}
.subject{background:#fff;border:3px solid var(--ink);border-radius:var(--radius);padding:22px;box-shadow:6px 6px 0 var(--ink);transition:transform .45s cubic-bezier(.34,1.56,.64,1),box-shadow .3s,opacity .7s}
.subject:nth-child(3n+1){--rest:-1.2deg}.subject:nth-child(3n+2){--rest:1deg}.subject:nth-child(3n){--rest:-.6deg}
.subject:hover{transform:rotate(0) translate(-3px,-5px) scale(1.02);box-shadow:10px 10px 0 var(--ink)}
.is-live{background:var(--saffron)}
.subject:nth-child(2){background:var(--sky)}.subject:nth-child(3){background:var(--mint)}.subject:nth-child(4){background:var(--pink)}
.subject-badge{display:inline-block;font-size:.72rem;font-weight:800;text-transform:uppercase;letter-spacing:.08em;background:#fff;border:2px solid var(--ink);border-radius:999px;padding:3px 10px}
.is-live .subject-badge{background:var(--ink);color:var(--saffron)}
.subject-name{font-size:1.45rem;font-weight:800;margin-top:14px}
.subject-note{font-weight:600;font-size:.9rem;margin-top:4px}
.subject-link{display:inline-block;margin-top:14px;font-weight:800;text-decoration:none;background:var(--ink);color:#fff;padding:8px 14px;border-radius:12px}
/* chapters */
.chapters{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,400px),1fr));gap:28px;margin-top:40px}
.chapter{background:#fff;border:3px solid var(--ink);border-radius:var(--radius);box-shadow:8px 8px 0 var(--ink);overflow:hidden;transition:transform .45s cubic-bezier(.34,1.56,.64,1),box-shadow .3s,opacity .7s}
.chapter:nth-child(odd){--rest:-1deg}.chapter:nth-child(even){--rest:1.2deg}
.chapter:hover{transform:rotate(0) translate(-3px,-6px);box-shadow:12px 12px 0 var(--ink)}
.chapter-media{border-bottom:3px solid var(--ink)}
.yt-play{border:3px solid var(--ink);box-shadow:4px 4px 0 var(--ink)}
.chapter-body{padding:20px 20px 22px}
.chapter-meta{color:var(--ink)}
.chapter-meta span:first-child{background:var(--sky);border:2px solid var(--ink);border-radius:999px;padding:2px 10px}
.chapter-topics li{font-size:.78rem;font-weight:700;border:2px solid var(--ink);border-radius:999px;padding:3px 10px;background:#FBF7EE}
.chapter-topics li:nth-child(3n+1){background:var(--mint)}.chapter-topics li:nth-child(3n+2){background:var(--pink)}
.soon-badge{background:var(--saffron);color:var(--ink);border:3px solid var(--ink);box-shadow:4px 4px 0 var(--ink);transform:translate(-50%,-50%) rotate(-4deg)}
/* why */
.whys{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:18px;margin-top:40px}
.why{border:3px solid var(--ink);border-radius:var(--radius);padding:24px;box-shadow:6px 6px 0 var(--ink);background:#fff;transition:transform .45s cubic-bezier(.34,1.56,.64,1),opacity .7s}
.why:nth-child(1){background:var(--mint);--rest:-1deg}.why:nth-child(2){background:var(--pink);--rest:1deg}.why:nth-child(3){background:var(--saffron);--rest:-.8deg}.why:nth-child(4){background:var(--sky);--rest:1.2deg}
.why:hover{transform:rotate(0) scale(1.03)}
.why h3{font-size:1.15rem;font-weight:800;margin-bottom:8px}
.why p{font-weight:600;font-size:.93rem;color:#1d2a4d}
/* how */
.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin-top:40px}
.step{background:#fff;border:3px solid var(--ink);border-radius:var(--radius);padding:26px 22px;box-shadow:6px 6px 0 var(--ink)}
.step:nth-child(2){--rest:1deg}.step:nth-child(1){--rest:-1deg}
.step-n{display:inline-grid;place-items:center;width:52px;height:52px;border-radius:50%;background:var(--saffron);border:3px solid var(--ink);font-weight:800;font-size:1.05rem;box-shadow:3px 3px 0 var(--ink)}
.step h3{font-size:1.2rem;font-weight:800;margin:16px 0 8px}
.step p{color:var(--muted);font-weight:600;font-size:.94rem}
/* notes */
.chip{background:#fff;border:2.5px solid var(--ink);font-weight:800;box-shadow:3px 3px 0 var(--ink);transition:transform .2s}
.chip:hover{transform:translate(-1px,-1px)}
.chip[aria-pressed=true]{background:var(--ink);color:var(--saffron)}
.note{background:#fff;border:3px solid var(--ink);border-radius:18px;box-shadow:5px 5px 0 var(--ink);transition:transform .35s cubic-bezier(.34,1.56,.64,1)}
.note:hover{transform:rotate(-.6deg) translate(-2px,-2px)}
.note-icon{background:var(--pink);border:2.5px solid var(--ink);color:var(--ink)}
.note .btn{box-shadow:3px 3px 0 var(--ink)}
/* about */
.about-card{display:grid;grid-template-columns:1fr auto;gap:30px;align-items:end;background:var(--sky);border:3px solid var(--ink);border-radius:28px;padding:clamp(26px,5vw,56px) clamp(26px,5vw,56px) 0;box-shadow:10px 10px 0 var(--ink);overflow:hidden}
.about-card>div{padding-bottom:clamp(26px,5vw,56px)}
.about-card .lead{color:#1d2a4d;font-weight:600}
.about-card .lead+.lead{margin-top:10px}
.social a{background:#fff;border:3px solid var(--ink);box-shadow:4px 4px 0 var(--ink);color:var(--ink)}
.social a:hover{transform:translate(-2px,-2px) rotate(-1deg)}
.site-footer{background:var(--ink);color:#fff;border-top:3px solid var(--ink);--muted:#B9C2DC;--line:rgba(255,255,255,.18)}
.site-footer .foot-grid>div>img{filter:brightness(0) invert(1)}
/* confetti */
.confetti{position:fixed;width:10px;height:14px;border:2px solid var(--ink);border-radius:3px;pointer-events:none;z-index:200;animation:conf 900ms cubic-bezier(.2,.7,.3,1) forwards}
@keyframes conf{to{transform:translate(var(--x),var(--y)) rotate(var(--rot));opacity:0}}
@media (max-width:860px){
  .hero-grid{grid-template-columns:1fr}
  .steps{grid-template-columns:1fr}
  .about-card{grid-template-columns:1fr}
  }

/* ---------- study stickers (replaced characters, v2) ---------- */
.sticker-board{position:relative;width:100%;max-width:520px;height:auto;aspect-ratio:1/1;margin-inline:auto}
.stk{position:absolute;filter:drop-shadow(3px 0 0 #fff) drop-shadow(-3px 0 0 #fff) drop-shadow(0 3px 0 #fff) drop-shadow(0 -3px 0 #fff) drop-shadow(5px 6px 0 rgba(11,26,58,.9))}
.stk svg{width:100%;height:auto;overflow:visible}
.s-graph{left:17%;top:15%;width:58%;z-index:2}
.s-badge{left:-2%;top:-1%;width:22%;z-index:4}
.s-coin{right:3%;top:3%;width:21%;z-index:3}
.s-bulb{right:2%;top:33%;width:19%;z-index:3}
.s-play{left:63%;top:59%;width:21%;z-index:5}
.s-stamp{left:1%;top:62%;width:30%;z-index:4}
.s-pdf{left:37%;top:66%;width:28%;z-index:3}
.doodle{position:absolute;overflow:visible;pointer-events:none}
.d-a1{left:3%;top:30%;width:16%;z-index:1;transform:rotate(14deg)}
.d-a2{right:1%;top:76%;width:18%;z-index:1}
.d-spark{left:31%;top:5%;width:8%;animation:spin 7s linear infinite}
/* the demand curve draws itself, the points land on it */
.g-curve{stroke-dasharray:1;stroke-dashoffset:1;animation:draw 1.6s cubic-bezier(.65,0,.35,1) 1.1s forwards}
.g-guides{opacity:0;animation:fadeIn .6s ease 2.4s forwards}
.g-dot,.g-lab{opacity:0;transform-box:fill-box;transform-origin:center;animation:dotPop .5s cubic-bezier(.34,1.56,.64,1) forwards}
.g-dot1{animation-delay:2.5s}.g-dot2{animation-delay:2.75s}.g-lab{animation-delay:2.9s}
.doodle .draw{stroke-dasharray:1;stroke-dashoffset:1;animation:draw .9s ease-out 1.8s forwards}
.doodle .tip{animation-delay:2.6s;animation-duration:.4s}
.d-a2 .draw{animation-delay:2.2s}.d-a2 .tip{animation-delay:3s}
@keyframes draw{to{stroke-dashoffset:0}}
@keyframes fadeIn{to{opacity:.7}}
@keyframes dotPop{from{opacity:0;transform:scale(0)}to{opacity:1;transform:scale(1)}}
@keyframes spin{to{transform:rotate(360deg)}}
/* coin flips, bulb glows, play pulses, stamp ring turns */
.coin-spin{transform-origin:center;animation:coinFlip 4.5s ease-in-out 2s infinite}
@keyframes coinFlip{0%,70%,100%{transform:rotateY(0)}85%{transform:rotateY(180deg)}}
.bulb-rays{animation:glow 1.8s ease-in-out infinite alternate}
@keyframes glow{from{opacity:.25}to{opacity:1}}
.play-tri{transform-box:fill-box;transform-origin:center;animation:pulse 1.6s ease-in-out infinite}
@keyframes pulse{50%{transform:scale(1.18)}}
.stamp-ring{transform-origin:75px 75px;animation:spin 18s linear infinite}
/* about: sticker art instead of a character */
.about-art{position:relative;width:280px;height:320px;align-self:center;margin-bottom:clamp(26px,5vw,56px)}
.a-note{left:6%;top:2%;width:80%;transform:rotate(var(--r))}
.a-coin{right:0;top:0;width:28%;transform:rotate(var(--r));animation:wobble 5s ease-in-out infinite}
.a-bulb{left:-4%;bottom:0;width:28%;transform:rotate(var(--r));animation:wobble 6s ease-in-out .8s infinite}
.a-curve{stroke-dasharray:1;stroke-dashoffset:1;transition:stroke-dashoffset 1.6s cubic-bezier(.65,0,.35,1) .4s}
.about-card.in .a-curve{stroke-dashoffset:0}
@media (max-width:860px){
  .sticker-board{max-width:380px;margin:18px auto 0}
  .about-art{width:220px;height:250px;justify-self:center;margin-top:0}
}
@media (prefers-reduced-motion:reduce){
  .g-curve,.doodle .draw,.a-curve{stroke-dashoffset:0!important}
  .g-dot,.g-lab{opacity:1!important}
  .g-guides{opacity:.7!important}
}
.btn-locked{background:var(--ivory);color:var(--muted);border:3px dashed var(--ink);box-shadow:none;cursor:default;font-weight:700;font-size:.9rem;min-height:48px;padding:0 16px}
.btn-locked:hover,.btn-locked:active{transform:none;box-shadow:none}
.note .btn-locked{box-shadow:none}