/* Wonder Steps Learning — site styles.
   Palette: paper (cool white), ink, pencil (cool grey), slate (the one brand
   colour), brass (a muted metal accent, used sparingly), rule (hairlines). */
:root{
  --paper:#F7F8FA; --paper-2:#EDEFF3; --ink:#1B2430; --pencil:#5C6B7E;
  --slate:#2C4A6E; --slate-soft:#E4E9F0; --on-slate:#FFFFFF;
  --brass:#8A6224; --rule:#D5DAE1;
  --shadow:rgba(27,36,48,.13);
  --display:'Archivo','Helvetica Neue',Arial,system-ui,sans-serif;
  --body:'Source Serif 4',Georgia,'Times New Roman',serif;
  --mono:ui-monospace,SFMono-Regular,'SF Mono',Menlo,Consolas,monospace;
  --step--1:clamp(.82rem,.79rem + .12vw,.9rem);
  --step-0:clamp(1rem,.96rem + .2vw,1.12rem);
  --step-1:clamp(1.2rem,1.12rem + .38vw,1.42rem);
  --step-2:clamp(1.5rem,1.36rem + .68vw,1.95rem);
  --step-3:clamp(2rem,1.7rem + 1.5vw,3.1rem);
  --gap:clamp(1.4rem,1rem + 1.6vw,2.4rem);
  --pad:clamp(1.15rem,.7rem + 2.2vw,2.6rem);
}
@media (prefers-color-scheme:dark){
  :root:not([data-theme="light"]){
    --paper:#12171F; --paper-2:#1A2029; --ink:#E8ECF2; --pencil:#9AA7B8;
    --slate:#8FB4DC; --slate-soft:#1E2937; --on-slate:#12171F;
    --brass:#D8AE6A; --rule:#2F3945;
    --shadow:rgba(0,0,0,.5);
  }
}
:root[data-theme="dark"]{
  --paper:#12171F; --paper-2:#1A2029; --ink:#E8ECF2; --pencil:#9AA7B8;
  --slate:#8FB4DC; --slate-soft:#1E2937; --on-slate:#12171F;
  --brass:#D8AE6A; --rule:#2F3945;
  --shadow:rgba(0,0,0,.5);
}
*,*::before,*::after{box-sizing:border-box}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--body);
  font-size:var(--step-0);line-height:1.62;-webkit-font-smoothing:antialiased}
h1,h2,h3{font-family:var(--display);font-weight:600;text-wrap:balance;line-height:1.1;
  letter-spacing:-.018em;margin:0}
p{margin:0}
a{color:inherit}
img{display:block;max-width:100%}
:focus-visible{outline:3px solid var(--brass);outline-offset:3px;border-radius:2px}
.wrap{width:min(1080px,100% - var(--pad)*2);margin-inline:auto}

/* the handwriting rule: faint top line, dashed midline, solid baseline —
   the paper these worksheets are printed on, used as the page's divider */
.ruled{position:relative;height:2.6rem}
.ruled::before{content:"";position:absolute;inset:0 0 auto;border-top:1px solid var(--rule)}
.ruled::after{content:"";position:absolute;left:0;right:0;top:50%;border-top:1px dashed var(--rule)}
.ruled i{position:absolute;left:0;right:0;bottom:0;display:block;border-top:2px solid var(--rule)}
.ruled.tight{height:1.7rem}

.masthead{padding-block:1.5rem .6rem}
.masthead .bar{display:flex;align-items:baseline;justify-content:space-between;gap:1.5rem;flex-wrap:wrap}
.mark{font-family:var(--display);font-weight:600;font-size:var(--step-1);letter-spacing:-.02em;
  text-decoration:none;display:flex;align-items:baseline;gap:.5rem}
.mark .steps{color:var(--slate)}
nav{display:flex;gap:1.35rem;flex-wrap:wrap;font-family:var(--display);font-size:var(--step--1)}
nav a{text-decoration:none;color:var(--pencil);padding-bottom:2px;border-bottom:2px solid transparent;
  transition:color .18s,border-color .18s}
nav a:hover{color:var(--ink);border-bottom-color:var(--brass)}
nav a[aria-current="page"]{color:var(--ink);border-bottom-color:var(--slate)}

/* One centred column. The sheets sit underneath in a flat row rather than
   beside the text, so the page opens on the words and then shows the goods. */
.hero{max-width:44rem;margin-inline:auto;text-align:center;
  padding-block:clamp(2.4rem,1.4rem + 4vw,5rem) 0}
.hero h1{font-size:var(--step-3)}
.hero .lede{font-size:var(--step-1);color:var(--pencil);margin:1.1rem auto 0;max-width:54ch}
.actions{display:flex;gap:1.6rem;flex-wrap:wrap;margin-top:1.9rem;align-items:center}
.hero .actions{justify-content:center}
.btn{font-family:var(--display);font-weight:600;font-size:var(--step-0);text-decoration:none;
  padding:.78em 1.6em;border-radius:2px;background:var(--slate);color:var(--on-slate);
  border:1px solid var(--slate);transition:background .18s,border-color .18s,color .18s}
.btn:hover{background:var(--ink);border-color:var(--ink);color:var(--paper)}
/* the second action is a plain link, not a second button */
.btn.ghost{background:none;border:none;padding:.78em 0;color:var(--ink);
  border-bottom:1px solid var(--brass);border-radius:0}
.btn.ghost:hover{background:none;color:var(--slate);border-bottom-color:var(--slate)}
.freenote{font-size:var(--step--1);color:var(--pencil);margin-top:1.3rem;font-family:var(--display)}

/* a flat, even row of real sheets — no fan, no rotation, no drop shadows */
.strip{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:1rem;
  margin-top:clamp(2rem,1.2rem + 3vw,3.4rem)}
.strip .peek{height:clamp(9rem,7rem + 8vw,14rem);overflow:hidden;border:1px solid var(--rule);
  border-bottom:none;background:#fff}
.strip img{width:100%;display:block}
.strip .ruled{grid-column:1/-1;margin-top:0}

section{padding-block:clamp(2.4rem,1.6rem + 3vw,4.2rem) 0}
.sechead{display:flex;align-items:baseline;justify-content:space-between;gap:1rem;flex-wrap:wrap}
.sechead h2{font-size:var(--step-2)}
.sechead .note{font-size:var(--step--1);color:var(--pencil);font-family:var(--display)}

.levels{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:var(--gap);margin-top:1.6rem}
.level{display:flex;flex-direction:column;gap:.9rem;text-decoration:none;color:inherit}
.level .shot{border:1px solid var(--rule);background:#fff;overflow:hidden;
  box-shadow:0 8px 20px -14px var(--shadow);transition:transform .2s,box-shadow .2s}
.level:hover .shot{transform:translateY(-4px);box-shadow:0 16px 30px -16px var(--shadow)}
.level .age{font-family:var(--display);font-size:var(--step--1);letter-spacing:.08em;
  text-transform:uppercase;color:var(--brass)}
.level h3{font-size:var(--step-1)}
.level .count{font-family:var(--display);font-weight:600;color:var(--slate);font-size:var(--step-0)}
.level p{color:var(--pencil);font-size:var(--step--1);line-height:1.55}
.level .go{font-family:var(--display);font-size:var(--step--1);color:var(--ink);
  border-bottom:2px solid var(--brass);align-self:flex-start;padding-bottom:1px;margin-top:.1rem}

.promises{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:var(--gap);margin-top:1.6rem}
.promise h3{font-family:var(--display);font-size:var(--step-0);margin-bottom:.3rem}
.promise p{font-size:var(--step--1);color:var(--pencil);line-height:1.55}
.promise svg{width:2.1rem;height:2.1rem;margin-bottom:.55rem;display:block}
.promise svg *{fill:none;stroke:var(--slate);stroke-width:5;stroke-linecap:round;stroke-linejoin:round}

.samples{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:var(--gap);margin-top:1.6rem}
.sample figure{margin:0}
.sample img{border:1px solid var(--rule);background:#fff;box-shadow:0 8px 20px -15px var(--shadow)}
.sample figcaption{display:flex;justify-content:space-between;gap:.6rem;align-items:baseline;
  margin-top:.6rem;font-size:var(--step--1)}
.sample .what{font-family:var(--display);color:var(--ink)}
.sample .code{font-family:var(--mono);font-size:.72rem;color:var(--pencil);letter-spacing:.02em}

.facts{display:flex;flex-wrap:wrap;gap:.5rem 2.6rem;margin-top:1.4rem;padding:1.3rem 0 0}
.fact{display:flex;align-items:baseline;gap:.55rem}
.fact b{font-family:var(--display);font-weight:600;font-size:var(--step-1);color:var(--slate);
  font-variant-numeric:tabular-nums}
.fact span{font-size:var(--step--1);color:var(--pencil)}

.closer{background:var(--slate-soft);padding:var(--pad);margin-top:2.6rem;border-left:3px solid var(--slate)}
.closer h2{font-size:var(--step-2);max-width:20ch}
.closer p{color:var(--pencil);margin-top:.7rem;max-width:52ch}

footer{padding-block:2rem 3rem;font-size:var(--step--1);color:var(--pencil)}
footer .row{display:flex;justify-content:space-between;gap:1rem;flex-wrap:wrap;padding-top:1.1rem}
footer a{color:var(--pencil)}

/* ------------------------------------------------------------ category page */
.crumb{font-family:var(--display);font-size:var(--step--1);color:var(--pencil);margin-top:1.4rem}
.crumb a{text-decoration:none;border-bottom:1px solid var(--rule)}
.bandhead{display:grid;grid-template-columns:minmax(0,1.15fr) minmax(0,.85fr);gap:var(--gap);
  align-items:end;padding-block:.8rem 0}
.bandhead h1{font-size:var(--step-3);margin-top:.3rem}
.bandhead .lede{color:var(--pencil);margin-top:.9rem;max-width:52ch}
.bandhead .tally{font-family:var(--display);font-weight:500;color:var(--slate);margin-top:.7rem;
  font-size:var(--step--1);display:flex;align-items:baseline;gap:.7rem;flex-wrap:wrap}
.bandhead .tally .age{color:var(--pencil);border:1px solid var(--rule);border-radius:2px;
  padding:.15em .55em;font-size:.78rem;letter-spacing:.04em;text-transform:uppercase}
.pair{display:flex;gap:1rem;align-items:flex-end}
.pair img{width:50%;border:1px solid var(--rule);background:#fff}

.jump{display:flex;gap:.6rem;flex-wrap:wrap;margin-top:1.4rem;font-family:var(--display);font-size:var(--step--1)}
.jump a,.jump button{text-decoration:none;border:1px solid var(--rule);padding:.4em .9em;
  border-radius:2px;transition:border-color .18s,color .18s;background:none;color:inherit;
  font-family:var(--display);font-size:inherit;cursor:pointer;line-height:inherit}
.jump a:hover,.jump button:hover{border-color:var(--slate);color:var(--slate)}
.jump button[aria-pressed="true"]{border-color:var(--slate);color:var(--slate)}

/* Each subject is a panel that starts rolled up: closed, the page is a short
   index of what the level covers; opened, it is the full sheet list. */
.subject{margin-top:clamp(1.6rem,1.1rem + 1.6vw,2.4rem)}
.subject > summary{list-style:none;cursor:pointer;padding-top:.2rem}
.subject > summary::-webkit-details-marker{display:none}
.sumbar{display:flex;align-items:baseline;justify-content:space-between;gap:1rem}
.sumbar h2{font-size:var(--step-2);transition:color .18s}
.subject:hover > summary .sumbar h2{color:var(--slate)}
.sumbar .cnt{font-family:var(--display);font-weight:400;font-size:var(--step--1);
  color:var(--pencil);margin-left:.6rem;white-space:nowrap}
.chev{width:1.5rem;height:1.5rem;flex:none;align-self:center;position:relative;
  border:1px solid var(--rule);border-radius:50%;transition:transform .2s,border-color .18s}
.chev::before{content:"";position:absolute;left:50%;top:46%;width:.42rem;height:.42rem;
  border-right:2px solid var(--pencil);border-bottom:2px solid var(--pencil);
  transform:translate(-50%,-60%) rotate(45deg)}
.subject[open] .chev{transform:rotate(180deg)}
.subject:hover .chev{border-color:var(--slate)}
.subject .note{font-size:var(--step--1);color:var(--pencil);max-width:62ch;margin-top:.45rem}
.subject > summary .ruled{margin-top:.7rem}
.group{margin-top:1.9rem}
.group > h3{font-family:var(--display);font-size:var(--step-0);letter-spacing:.02em;
  color:var(--pencil);text-transform:uppercase;font-size:var(--step--1)}
.sheetlist{margin-top:.5rem;border-top:1px solid var(--rule)}
.sheet-row{display:grid;grid-template-columns:1.6rem minmax(0,1fr) auto auto;gap:.9rem;
  align-items:baseline;padding:.62rem .5rem;border-bottom:1px solid var(--rule);
  text-decoration:none;color:inherit;transition:background .15s}
.sheet-row:hover{background:var(--paper-2)}
.sheet-row .num{font-family:var(--mono);font-size:.72rem;color:var(--rule)}
.sheet-row .t{font-family:var(--display);font-size:var(--step-0)}
.sheet-row .keyed{font-size:.7rem;font-family:var(--display);color:var(--slate);
  border:1px solid var(--slate-soft);background:var(--slate-soft);padding:.1em .5em;border-radius:2px;
  white-space:nowrap}
.sheet-row .dl{font-family:var(--display);font-size:var(--step--1);color:var(--pencil);white-space:nowrap}
.sheet-row:hover .dl{color:var(--slate)}

@media (max-width:900px){
  .hero,.bandhead{grid-template-columns:1fr}
  .fan,.bandhead .pair{order:-1}
  .levels{grid-template-columns:repeat(2,minmax(0,1fr))}
  .samples{grid-template-columns:1fr}
  .strip{grid-template-columns:repeat(3,minmax(0,1fr))}
  .strip .peek:nth-child(n+4){display:none}
  .promises{grid-template-columns:repeat(2,minmax(0,1fr))}
  .sheet-row{grid-template-columns:1.4rem minmax(0,1fr) auto;row-gap:.2rem}
  .sheet-row .keyed{display:none}
}
@media (max-width:620px){
  .levels{grid-template-columns:1fr}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important}}