/* Star Steps Library (2026-10-06): warm paper look, grade shelves, a page-turning reader. */
:root{--paper:#fbf7ef;--paper2:#f3ecdd;--ink:#1d1b33;--muted:#6b6880;--line:#e6dfcf;--accent:#5b4ee0;--accent2:#e07a2a;--star:#F2C46D;--card:#fff;
 --display:ui-rounded,"SF Pro Rounded","Baloo 2","Nunito","Quicksand","Trebuchet MS",system-ui,sans-serif;--body:ui-rounded,"SF Pro Rounded","Nunito","Quicksand","Avenir Next",system-ui,sans-serif;--mono:ui-rounded,"SF Pro Rounded","Nunito",system-ui,sans-serif}
*{box-sizing:border-box}html{background:var(--paper);scroll-behavior:smooth}
[hidden]{display:none!important}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--body);font-size:16px;line-height:1.55;-webkit-font-smoothing:antialiased}
img{max-width:100%}button{font:inherit;cursor:pointer}
button:focus-visible,a:focus-visible,select:focus-visible{outline:3px solid var(--accent);outline-offset:2px}
.wrap{max-width:1180px;margin:0 auto;padding:0 16px}
/* hero */
.hero{display:grid;grid-template-columns:1.2fr 1fr;gap:24px;align-items:center;padding:34px 0 10px}
.hero h1{font-family:var(--display);font-weight:900;font-size:clamp(34px,6vw,60px);line-height:1.02;margin:0 0 10px;letter-spacing:-.01em}
.hero h1 i{font-style:italic;color:var(--accent2)}
.hero p{margin:0 0 14px;color:var(--muted);font-size:17px;max-width:54ch}
.eyebrow{font-family:var(--display);font-weight:800;font-size:13px;letter-spacing:.08em;text-transform:uppercase;color:var(--accent2);margin-bottom:8px}
.stats{display:flex;flex-wrap:wrap;gap:8px 18px;font-size:14px;color:var(--muted)}
.stats b{display:block;font-family:var(--display);font-weight:900;font-size:26px;color:var(--ink);line-height:1.1}
.hero-art{position:relative;aspect-ratio:2/1;border-radius:18px;overflow:hidden;box-shadow:0 20px 50px rgba(40,30,80,.18)}
.hero-art canvas{display:block;width:100%;height:100%}
.hero-art span{position:absolute;left:12px;bottom:10px;font-family:var(--mono);font-size:11px;color:#fff;background:rgba(20,18,30,.6);padding:4px 8px;border-radius:999px}
/* controls */
.bar{position:sticky;top:48px;z-index:20;background:rgba(251,247,239,.94);backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px);border-bottom:1px solid var(--line);padding:10px 0}
.bar .wrap{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.chips{display:flex;gap:6px;overflow-x:auto;scrollbar-width:none;padding:2px}
.chips::-webkit-scrollbar{display:none}
.chip{white-space:nowrap;border:1px solid var(--line);background:var(--card);color:var(--muted);border-radius:999px;padding:7px 13px;font-weight:600;font-size:13px}
.chip[aria-pressed="true"]{background:var(--accent);border-color:var(--accent);color:#fff}
.search{margin-left:auto;display:flex;align-items:center;gap:6px;border:1px solid var(--line);background:var(--card);border-radius:999px;padding:4px 6px 4px 12px;min-width:200px;min-height:40px}
.search input{border:0;outline:0;background:none;font:inherit;font-size:15px;width:100%;color:var(--ink);min-height:32px}
.search input::placeholder{color:#9b98ad}
select.sel{border:1px solid var(--line);background:var(--card);border-radius:999px;padding:7px 10px;font-size:13px;font-weight:600;color:var(--muted)}
/* continue row */
.cont[hidden]{display:none}
.cont{margin:18px 0 6px;padding:14px 16px;border-radius:16px;background:linear-gradient(100deg,#efeaff,#fff6ea);border:1px solid #e3dcff;display:flex;gap:14px;align-items:center;flex-wrap:wrap}
.cont h2{margin:0;font-size:15px;font-family:var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--accent);font-weight:600;flex:1 1 100%}
.cont-item{display:flex;gap:10px;align-items:center;border:0;background:var(--card);border-radius:12px;padding:8px 12px 8px 8px;text-align:left;box-shadow:0 2px 8px rgba(40,30,80,.08)}
.cont-item .mini{width:34px;height:46px;border-radius:3px 6px 6px 3px;flex:0 0 auto;box-shadow:inset 4px 0 0 rgba(0,0,0,.2)}
.cont-item b{display:block;font-size:14px}.cont-item small{color:var(--muted);font-size:12px}
/* shelves */
.shelf{padding:26px 0 8px}
.shelf-h{display:flex;align-items:baseline;gap:12px;flex-wrap:wrap;margin-bottom:12px}
.shelf-h h2{margin:0;font-family:var(--display);font-size:clamp(22px,3.4vw,30px);font-weight:900}
.shelf-h small{color:var(--muted);font-size:14px}
.books{display:grid;grid-template-columns:repeat(auto-fill,minmax(168px,1fr));gap:18px 16px;padding:0 0 18px;position:relative}
.books::after{content:"";position:absolute;left:-8px;right:-8px;bottom:0;height:10px;border-radius:4px;background:linear-gradient(#c9a67a,#8a6a44);box-shadow:0 6px 10px rgba(80,50,20,.25)}
.book{display:grid;gap:8px;border:0;background:none;padding:0;text-align:left;color:var(--ink);min-width:0;align-content:start}
.cov{position:relative;aspect-ratio:3/4;border-radius:4px 12px 12px 4px;overflow:hidden;box-shadow:inset 8px 0 0 rgba(0,0,0,.22),0 10px 22px rgba(40,30,80,.2);transition:transform .2s,box-shadow .2s;background:#333}
.cov canvas{position:absolute;inset:0;width:100%;height:100%;object-fit:cover}
.cov::after{content:"";position:absolute;left:0;right:0;bottom:0;height:58%;background:linear-gradient(rgba(0,0,0,0),rgba(0,0,0,.72));pointer-events:none}
.cov .ttl,.cov .prog,.cov .done,.cov .tag{z-index:1}
.cov .ttl{position:absolute;left:14px;right:10px;bottom:12px;color:#fff;text-shadow:0 2px 10px rgba(0,0,0,.6)}
.cov .ttl b{display:block;font-family:var(--display);font-weight:900;font-size:17px;line-height:1.1;text-wrap:balance}
.cov .ttl small{display:block;font-size:11px;opacity:.9;margin-top:4px}
.cov .tag{position:absolute;top:10px;left:16px;font-family:var(--display);font-weight:800;font-size:11px;letter-spacing:.06em;color:#fff;background:rgba(20,18,30,.55);padding:3px 7px;border-radius:999px}
.cov .done{position:absolute;top:8px;right:8px;width:26px;height:26px;border-radius:50%;background:#3ddc5a;color:#083;display:grid;place-items:center;font-weight:900;font-size:14px}
.cov .prog{position:absolute;left:8px;right:0;bottom:0;height:5px;background:rgba(255,255,255,.3)}.cov .prog i{display:block;height:100%;background:var(--star)}
.book:hover .cov,.book:focus-visible .cov{transform:translateY(-5px) rotate(-1deg);box-shadow:inset 8px 0 0 rgba(0,0,0,.22),0 18px 30px rgba(40,30,80,.28)}
.book .meta{font-size:12px;color:var(--muted);line-height:1.35}
.book .meta b{color:var(--ink);font-weight:600}
.empty{color:var(--muted);padding:30px 0;text-align:center}
/* edge shelf */
.edge-shelf{margin:30px 0 10px;padding:22px;border-radius:18px;background:#0E1018;color:#EDE9F5;display:grid;grid-template-columns:1fr auto;gap:14px;align-items:center}
.edge-shelf h2{margin:0 0 4px;font-family:var(--display);font-size:26px;font-weight:900}
.edge-shelf h2 i{color:var(--star)}
.edge-shelf p{margin:0;color:#A29EB5;font-size:15px;max-width:60ch}
.edge-shelf a{display:inline-block;background:var(--star);color:#1b1206;font-weight:700;text-decoration:none;padding:12px 18px;border-radius:999px}
.edge-books{grid-column:1/-1;display:flex;gap:10px;overflow-x:auto;padding:6px 2px 2px;scrollbar-width:thin}
.edge-books a{flex:0 0 auto;display:grid;gap:4px;width:118px;padding:0;background:none;color:#EDE9F5;font-weight:500;text-decoration:none}
.edge-books .ecov{aspect-ratio:3/4;border-radius:3px 8px 8px 3px;box-shadow:inset 6px 0 0 rgba(0,0,0,.25);display:flex;align-items:flex-end;padding:8px}
.edge-books .ecov b{font-family:var(--display);font-weight:400;font-size:14px;line-height:1.1;color:#1a1208;background:rgba(250,245,232,.93);padding:5px 7px;border-radius:4px;width:100%}
.edge-books small{font-size:11px;color:#A29EB5}
footer.lf{color:var(--muted);font-size:14px;padding:26px 0 40px;border-top:1px solid var(--line);margin-top:26px}
footer.lf a{color:var(--accent);display:inline-block;padding:6px 2px}
@media (max-width:860px){.hero{grid-template-columns:1fr;padding-top:22px}.hero-art{max-width:520px}.edge-shelf{grid-template-columns:1fr}.search{margin-left:0;flex:1 1 100%}}
@media (max-width:560px){.books{grid-template-columns:repeat(2,minmax(0,1fr));gap:14px 12px}.cov .ttl b{font-size:15px}}

/* ================= READER ================= */
.rd{position:fixed;inset:0;z-index:60;background:rgba(28,24,40,.92);backdrop-filter:blur(6px);-webkit-backdrop-filter:blur(6px);display:flex;flex-direction:column;align-items:center;justify-content:center;gap:10px;padding:calc(10px + env(safe-area-inset-top,0px)) 10px calc(10px + env(safe-area-inset-bottom,0px))}
.rd-bar{width:min(1120px,100%);display:flex;align-items:center;gap:8px 10px;color:#fff;flex-wrap:wrap}
.rd-title{font-family:var(--display);font-size:22px;font-weight:900;margin-right:auto;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.rd-cnt{font-family:var(--mono);font-size:12px;color:#c9c4e0}
.rd-btn{border:1px solid rgba(255,255,255,.3);background:rgba(255,255,255,.08);color:#fff;border-radius:999px;padding:7px 13px;font-weight:600;font-size:13px}
.rd-btn[aria-pressed="true"]{background:var(--star);color:#1b1206;border-color:var(--star)}
.rd-x{width:38px;height:38px;padding:0;font-size:22px;line-height:1;display:grid;place-items:center}
.rd-stage{display:flex;align-items:center;gap:10px;width:min(1180px,100%);justify-content:center}
.rd-nav{flex:0 0 auto;width:46px;height:46px;border-radius:50%;border:1px solid rgba(255,255,255,.3);background:rgba(255,255,255,.1);color:#fff;font-size:28px;line-height:1}
.rd-nav:disabled{opacity:.25;cursor:default}
.bk{position:relative;display:grid;grid-template-columns:1fr 1fr;width:min(1040px,calc(100vw - 130px));height:min(720px,calc(100vh - 150px));perspective:2400px;filter:drop-shadow(0 30px 50px rgba(0,0,0,.5))}
.bk.one{grid-template-columns:1fr;width:min(560px,calc(100vw - 20px));height:min(720px,calc(100vh - 130px))}
.pg,.face{position:relative;overflow:hidden;background:#fffdf8;background-image:radial-gradient(120% 90% at 50% 40%,#fffdf8 0%,#f8f2e6 75%,#efe6d4 100%);color:var(--ink);font-family:var(--body)}
.pg-l{border-radius:12px 2px 2px 12px;box-shadow:inset -26px 0 30px -18px rgba(90,60,20,.35)}
.pg-r{border-radius:2px 12px 12px 2px;box-shadow:inset 26px 0 30px -18px rgba(90,60,20,.35)}
.bk.one .pg-r{border-radius:12px;box-shadow:none}
.leaf{position:absolute;top:0;bottom:0;width:50%;transform-style:preserve-3d;transition:transform .7s cubic-bezier(.45,.05,.3,1);z-index:3}
.leaf.go-next{right:0;transform-origin:left center}.leaf.go-prev{left:0;transform-origin:right center}
.leaf.one{width:100%;left:0;right:auto}
.leaf.go-next.turning{transform:rotateY(-180deg)}.leaf.go-prev.turning{transform:rotateY(180deg)}
.face{position:absolute;inset:0;backface-visibility:hidden;-webkit-backface-visibility:hidden}
.front{border-radius:2px 12px 12px 2px}.back{transform:rotateY(180deg);border-radius:12px 2px 2px 12px}
.leaf.go-prev .front{border-radius:12px 2px 2px 12px}.leaf.go-prev .back{border-radius:2px 12px 12px 2px}
.in{position:absolute;inset:0;padding:clamp(18px,3.4vw,38px) clamp(18px,3.4vw,40px) 42px;overflow-y:auto;display:grid;gap:10px;align-content:start;font-size:var(--fs,16px)}
.in h3{font-family:var(--display);font-weight:900;font-size:clamp(22px,2.6vw,30px);line-height:1.1;margin:0;text-wrap:balance}
.in p{margin:0;line-height:1.6}
.eye{font-family:var(--display);font-weight:800;font-size:12px;letter-spacing:.1em;text-transform:uppercase;color:var(--accent2)}
.drop::first-letter{float:left;font-family:var(--display);font-weight:900;font-size:2.8em;line-height:.85;padding:4px 8px 0 0;color:var(--accent)}
.fig{margin:0;display:grid;gap:6px}
.fig canvas{display:block;width:100%;aspect-ratio:2/1;border-radius:10px;background:#111;box-shadow:0 6px 18px rgba(40,30,80,.2)}
.fig figcaption{font-size:13px;color:var(--muted);font-style:italic;line-height:1.4}
.fact{border-left:4px solid var(--star);background:#fff6dc;padding:10px 12px;border-radius:0 10px 10px 0;font-size:14px;line-height:1.5}
.fact b{display:block;font-family:var(--mono);font-size:10px;letter-spacing:.14em;text-transform:uppercase;color:#9a5a1c;margin-bottom:2px}
.num{text-align:center;font-family:var(--mono);font-size:11px;color:#9a8a6a;padding-top:6px}
.in{padding-bottom:18px}
.bk.g4 .fig canvas,.bk.g5 .fig canvas{aspect-ratio:2.6/1}.bk.g6 .fig canvas,.bk.g7 .fig canvas{aspect-ratio:3/1}
.bk.g5 .in,.bk.g6 .in,.bk.g7 .in{font-size:var(--fs,15px)}
.pg::after,.face::after{content:"";position:absolute;left:0;right:0;bottom:0;height:26px;background:linear-gradient(rgba(248,242,230,0),rgba(240,230,212,.9));pointer-events:none}
/* cover */
.cover{position:absolute;inset:0;display:flex;flex-direction:column;justify-content:flex-end;padding:0;color:#fff;background:#222}
.cover canvas{position:absolute;inset:0;width:100%;height:100%;object-fit:cover}
.cover .ct{position:relative;padding:28px 28px 34px;background:linear-gradient(rgba(0,0,0,0),rgba(0,0,0,.75));text-shadow:0 2px 12px rgba(0,0,0,.6)}
.cover .lib{font-family:var(--display);font-weight:800;font-size:11px;letter-spacing:.12em;color:var(--star);margin-bottom:8px}
.cover h2{font-family:var(--display);font-weight:900;font-size:clamp(30px,4.2vw,50px);line-height:1;margin:0}
.cover .sub{font-style:italic;font-size:18px;margin:8px 0 0;opacity:.95}
.cover .for{font-family:var(--mono);font-size:11px;margin:14px 0 0;opacity:.85}
.toc{list-style:none;margin:6px 0 0;padding:0;display:grid;gap:8px;font-size:15px}
.toc li{display:flex;align-items:baseline;gap:8px}.toc i{flex:1;border-bottom:1px dotted #b8a888}.toc em{font-style:normal;font-family:var(--mono);font-size:12px}
.toc li.sub{font-size:13px;color:var(--muted);padding-left:14px}
/* try */
.steps{margin:0;padding-left:22px;display:grid;gap:8px;line-height:1.5}
.safe{background:#ffe9e9;border-left:4px solid #d9463a;padding:8px 12px;border-radius:0 10px 10px 0;font-size:14px}
.safe b{color:#b3261e}
/* quiz */
.qz{display:grid;gap:10px;align-content:center;height:100%}
.qz .qq{font-family:var(--display);font-size:clamp(20px,2.4vw,27px);font-weight:900;line-height:1.2;margin:0}
.opts{display:grid;gap:8px}
.opts button{text-align:left;font-weight:600;font-size:15px;padding:12px 14px;border-radius:12px;border:2px solid var(--line);background:#fff;color:var(--ink)}
.opts button:hover:not(:disabled){border-color:var(--accent)}
.opts button.right{border-color:#3ddc5a;background:#eafff0}.opts button.wrong{border-color:#ff8a8a;background:#fff0f0}
.fb{min-height:1.5em;margin:0;font-weight:600}
/* big */
.big{position:absolute;inset:0;background:#111}
.big canvas{position:absolute;inset:0;width:100%;height:100%;object-fit:cover}
.big .bt{position:absolute;left:0;right:0;bottom:0;padding:26px 28px 36px;color:#fff;background:linear-gradient(rgba(0,0,0,0),rgba(0,0,0,.8));text-shadow:0 2px 10px rgba(0,0,0,.7)}
.big h3{color:#fff;font-size:clamp(24px,3vw,36px)}
.big p{margin-top:8px;font-size:16px;line-height:1.5}
/* words / think / end */
.dl{margin:0;display:grid;gap:2px}.dl dt{font-weight:700;margin-top:8px;color:var(--accent)}.dl dd{margin:0;font-size:15px;line-height:1.5}
.qs{margin:0;padding-left:22px;display:grid;gap:12px;font-size:16px;line-height:1.5}
.note{font-size:13px;color:var(--muted);font-style:italic}
.endp{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;gap:10px;padding:30px}
.endp h2{font-family:var(--display);font-size:46px;margin:0;font-weight:900}
.endp .star{font-size:54px;line-height:1}
.endp .btn{background:var(--accent);color:#fff;border:0;border-radius:999px;padding:12px 20px;font-weight:700;font-size:15px}
.endp .btn.sec{background:#fff;color:var(--accent);border:2px solid var(--accent)}
.hint{margin:0;font-family:var(--mono);font-size:11px;color:#c9c4e0}
@media (max-width:760px){.rd{justify-content:flex-start}.rd-nav{display:none}.rd-title{font-size:17px;flex:1 1 100%;margin:0}.rd-bar{gap:6px}.bk.one{height:calc(100dvh - 150px)}.cover .ct{padding:22px 20px 30px}.hint{display:none}}
@media (prefers-reduced-motion:reduce){.leaf{transition:none}.book .cov{transition:none}}

/* ---- small grades (SK–Grade 2): a friendlier book ---- */
.bk.kid .pg,.bk.kid .face{background:#fffbea;background-image:radial-gradient(120% 90% at 50% 40%,#fffdf3 0%,#fff6d6 75%,#ffeec0 100%)}
.bk.kid .in{font-size:var(--fs,19px);gap:14px}
.bk.kid .in p{line-height:1.75}
.bk.kid .in h3{font-size:clamp(26px,3vw,34px);color:#5b4ee0}
.bk.kid .eye{color:#e07a2a}
.bk.kid .fig canvas{border-radius:18px;box-shadow:0 8px 0 #f3d9a0,0 14px 24px rgba(120,80,20,.18)}
.bk.kid .fig figcaption{font-size:14px;color:#7a5a30;font-style:normal;font-weight:600}
.bk.kid .fact{background:#e9f8ee;border-left-color:#3ddc5a;border-radius:14px;padding:12px 14px;font-size:15px}
.bk.kid .fact b{color:#1d8a3a}
.bk.kid .drop::first-letter{color:#e07a2a}
.bk.kid .cover .ct{background:linear-gradient(rgba(0,0,0,0),rgba(0,0,0,.6))}
.bk.kid .cover .lib{display:inline-block;background:rgba(20,18,30,.55);padding:4px 9px;border-radius:999px;color:#ffe08a}
.bk.kid .cover .pip{position:absolute;right:14px;top:14px;width:clamp(72px,14%,110px);height:auto;filter:drop-shadow(0 6px 10px rgba(0,0,0,.35));animation:pipbob 3s ease-in-out infinite}
@keyframes pipbob{50%{transform:translateY(-6px) rotate(-4deg)}}
.pipq{display:flex;align-items:center;gap:10px;font-family:var(--display);font-weight:900;color:#e07a2a;font-size:16px}
.pipq img{width:56px;height:auto}
.bk.kid .opts button{border-radius:16px;font-size:17px;padding:14px 16px;border-width:3px}
.bk.kid .opts button.right{background:#dcffe6}
.bk.kid .endp .pip{width:120px;height:auto;animation:pipbob 3s ease-in-out infinite}
.bk.kid .endp h2{color:#5b4ee0}
.bk.kid .toc{font-size:17px}
.bk.kid .steps{font-size:17px;line-height:1.7}
.bk.kid .dl dt{font-size:18px}.bk.kid .dl dd{font-size:16px}
.bk.kid .qs{font-size:18px}
@media (prefers-reduced-motion:reduce){.bk.kid .cover .pip,.bk.kid .endp .pip{animation:none}}