/* ===========================================================
   math.manilyn.net — shared styles  (geometric / interactive-math)
   =========================================================== */
:root{
  --bg:#f6f7fc;
  --panel:#ffffff;
  --ink:#161a2e;
  --ink-soft:#535975;
  --line:#dde2f2;
  --blue:#2f5cf6;
  --blue-soft:#e9eeff;
  --teal:#0fb6a8;
  --coral:#ff6a5a;
  --amber:#f6a821;
  --green:#1faa5a;
  --shadow:0 14px 36px rgba(22,26,46,.10);
  --maxw:1020px;
  color-scheme:light;
}
*{box-sizing:border-box;}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%;}
body{
  margin:0; color:var(--ink); background:var(--bg);
  font-family:"Manrope", system-ui, sans-serif; font-size:17px; line-height:1.65;
  background-image:radial-gradient(rgba(47,92,246,.07) 1.1px, transparent 1.1px);
  background-size:26px 26px;
}
.wrap{max-width:var(--maxw); margin:0 auto; padding:0 clamp(1rem,4vw,2rem);}
a{color:var(--blue); text-decoration:none;}
a:hover{text-decoration:underline;}
h1,h2,h3,h4{font-family:"Sora", system-ui, sans-serif; line-height:1.12; color:var(--ink); font-weight:800;}
.mono{font-family:"Space Mono", ui-monospace, monospace;}

/* ---------- top nav ---------- */
.topnav{
  position:sticky; top:0; z-index:50; background:rgba(246,247,252,.9);
  backdrop-filter:blur(8px); border-bottom:1px solid var(--line);
}
.topnav .row{display:flex; align-items:center; gap:1rem; padding:.7rem clamp(1rem,4vw,2rem); max-width:var(--maxw); margin:0 auto;}
.brand{display:flex; align-items:center; gap:.6rem; font-family:"Sora",sans-serif; font-weight:800; font-size:1.05rem; color:var(--ink);}
.brand:hover{text-decoration:none;}
.brand svg{display:block;}
.brand .logo-poly{transform-origin:50% 50%; animation:spin 16s linear infinite;}
@keyframes spin{to{transform:rotate(360deg);}}
.brand b{color:var(--blue);}
.navlinks{margin-left:auto; display:flex; gap:.3rem 1.3rem; flex-wrap:wrap; align-items:center;
  font-family:"Sora",sans-serif; font-weight:600; font-size:.84rem;}
.navlinks a{color:var(--ink-soft); padding:.3rem 0; border-bottom:2px solid transparent;}
.navlinks a:hover{color:var(--ink); text-decoration:none;}
.navlinks a.active{color:var(--blue); border-bottom-color:var(--blue);}

/* ---------- footer ---------- */
.foot{margin-top:4rem; border-top:1px solid var(--line); background:var(--ink); color:#c7cce4;}
.foot .row{max-width:var(--maxw); margin:0 auto; padding:1.6rem clamp(1rem,4vw,2rem); display:flex; flex-wrap:wrap; gap:.6rem 1.4rem; align-items:center; font-size:.8rem; font-family:"Sora",sans-serif;}
.foot a{color:#fff;}
.foot .sp{margin-left:auto; color:#8089ad;}

/* ---------- hero ---------- */
.hero{padding:clamp(2rem,6vw,4rem) 0 1.5rem;}
.kicker{display:inline-block; font-family:"Space Mono",monospace; font-size:.72rem; letter-spacing:.18em; text-transform:uppercase;
  color:var(--blue); background:var(--blue-soft); padding:.35rem .7rem; border-radius:999px;}
.hero h1{font-size:clamp(2.3rem,7vw,4rem); margin:1rem 0 .4rem; letter-spacing:-.02em;}
.hero .lead{font-size:clamp(1.05rem,2.4vw,1.3rem); color:var(--ink-soft); max-width:54ch; margin:0;}

/* ---------- lesson layout ---------- */
.lesson{padding-bottom:2rem;}
.sec{margin:2.6rem 0 0; scroll-margin-top:5rem;}
.sec > h2{font-size:clamp(1.5rem,4vw,2.1rem); margin:0 0 .3rem; display:flex; align-items:center; gap:.6rem;}
.sec > h2 .num{font-family:"Space Mono",monospace; font-size:.9rem; color:#fff; background:var(--blue);
  width:1.9rem; height:1.9rem; display:inline-grid; place-items:center; border-radius:8px; flex:0 0 auto;}
.sec h3{font-size:1.18rem; margin:1.6rem 0 .5rem;}
.sec p{margin:.6rem 0;}
.sec ul{margin:.5rem 0 .9rem; padding-left:1.2rem;}
.sec li{margin:.3rem 0;}
.divider{height:0; border:0; border-top:2px dashed var(--line); margin:2.4rem 0;}
.mirror-divider{display:flex; align-items:center; gap:.8rem; margin:2.4rem 0; color:var(--ink-soft);}
.mirror-divider::before,.mirror-divider::after{content:""; height:1px; background:var(--line); flex:1;}

/* ---------- panels / callouts ---------- */
.card{background:var(--panel); border:1px solid var(--line); border-radius:16px; box-shadow:var(--shadow); padding:1.2rem 1.3rem;}
.callout{border-left:4px solid var(--teal); background:#eafaf8; border-radius:0 12px 12px 0; padding:.9rem 1.1rem; margin:1rem 0;}
.callout.warn{border-color:var(--amber); background:#fff6e6;}
.callout.note{border-color:var(--blue); background:var(--blue-soft);}
.callout b{color:var(--ink);}
.deflbl{font-family:"Space Mono",monospace; font-size:.68rem; letter-spacing:.16em; text-transform:uppercase; color:var(--ink-soft);}

/* algebraic test highlight */
.test{display:flex; flex-wrap:wrap; align-items:center; gap:.6rem 1rem; background:var(--ink); color:#eef1ff;
  border-radius:14px; padding:.9rem 1.1rem; margin:1rem 0; font-size:1.05rem;}
.test .tlab{font-family:"Space Mono",monospace; font-size:.66rem; letter-spacing:.16em; text-transform:uppercase; color:var(--amber);}
.test .katex{color:#fff;}

/* worked example (expandable) */
details.ex{border:1px solid var(--line); border-radius:14px; background:var(--panel); margin:1rem 0; overflow:hidden;}
details.ex>summary{cursor:pointer; list-style:none; padding:.85rem 1.1rem; font-family:"Sora",sans-serif; font-weight:700;
  display:flex; align-items:center; gap:.6rem; color:var(--ink); background:#f2f4fd;}
details.ex>summary::-webkit-details-marker{display:none;}
details.ex>summary .chev{margin-left:auto; transition:transform .2s; color:var(--blue);}
details.ex[open]>summary .chev{transform:rotate(90deg);}
details.ex .body{padding:.4rem 1.1rem 1.1rem;}
.steps{counter-reset:s; list-style:none; padding:0; margin:.5rem 0;}
.steps li{position:relative; padding:.45rem 0 .45rem 2.2rem; border-bottom:1px dashed var(--line);}
.steps li:last-child{border-bottom:0;}
.steps li::before{counter-increment:s; content:counter(s); position:absolute; left:0; top:.4rem;
  width:1.5rem; height:1.5rem; background:var(--blue-soft); color:var(--blue); border-radius:7px;
  display:grid; place-items:center; font-family:"Space Mono",monospace; font-size:.75rem; font-weight:700;}
.verdict{font-family:"Sora",sans-serif; font-weight:800; padding:.5rem .8rem; border-radius:10px; display:inline-block; margin-top:.4rem;}
.verdict.yes{background:#e4f7ec; color:var(--green);}
.verdict.no{background:#ffe9e6; color:var(--coral);}

/* ---------- graph widgets ---------- */
.graph{background:var(--panel); border:1px solid var(--line); border-radius:16px; box-shadow:var(--shadow); padding:1rem; margin:1rem 0;}
.graph .gtitle{font-family:"Sora",sans-serif; font-weight:700; font-size:.95rem; margin:0 0 .5rem; display:flex; gap:.5rem; align-items:center;}
.graph svg{width:100%; max-width:340px; height:auto; display:block; margin:.2rem auto; touch-action:none;}
  .graph svg.wide{max-width:100%; margin:0;}
  .iconrow svg{width:auto; max-width:110px; margin:0;}
.gline{stroke:var(--line); stroke-width:1;}
.gaxis{stroke:#9aa2c6; stroke-width:1.6;}
.gcurve{fill:none; stroke:var(--ink); stroke-width:3; stroke-linecap:round; stroke-linejoin:round;}
.gmirror{fill:none; stroke:var(--coral); stroke-width:3; stroke-dasharray:7 6; stroke-linecap:round; opacity:0; transition:opacity .5s;}
.gmirror.show{opacity:1;}
.gaxisline{stroke:var(--blue); stroke-width:2; stroke-dasharray:3 4; opacity:.0; transition:opacity .4s;}
.gaxisline.show{opacity:.9;}
.gticktxt{font-family:"Space Mono",monospace; font-size:9px; fill:#8089ad;}
.gctrls{display:flex; flex-wrap:wrap; gap:.5rem; margin-top:.7rem;}
.btn{font-family:"Sora",sans-serif; font-weight:700; font-size:.82rem; cursor:pointer; border:1.5px solid var(--ink);
  background:var(--panel); color:var(--ink); border-radius:10px; padding:.5rem .9rem; transition:all .15s;}
.btn:hover{background:var(--ink); color:#fff;}
.btn.accent{border-color:var(--blue); color:#fff; background:var(--blue);}
.btn.accent:hover{background:#1f49d8;}
.gnote{font-size:.85rem; color:var(--ink-soft); margin-top:.5rem; min-height:1.2em;}

/* ---------- tester / walkthrough ---------- */
.tester{background:var(--panel); border:1px solid var(--line); border-radius:18px; box-shadow:var(--shadow); overflow:hidden; margin:1.2rem 0;}
.tester .head{background:var(--ink); color:#fff; padding:1rem 1.2rem;}
.tester .head .eq{font-size:1.3rem; margin-top:.3rem;}
.tester .head .eq .katex{color:#fff;}
.ttabs{display:flex; flex-wrap:wrap; gap:.4rem; padding:1rem 1.2rem 0;}
.ttab{font-family:"Sora",sans-serif; font-weight:700; font-size:.82rem; cursor:pointer; border:1.5px solid var(--line);
  background:#f2f4fd; color:var(--ink-soft); border-radius:10px 10px 0 0; padding:.55rem .9rem;}
.ttab.on{background:var(--panel); color:var(--blue); border-color:var(--line); border-bottom-color:var(--panel); position:relative; top:1px;}
.tpanels{border-top:1px solid var(--line); padding:1.1rem 1.2rem 1.3rem;}
.tpanel{display:none;}
.tpanel.on{display:block;}

/* ---------- quiz ---------- */
.quiz{margin:1.2rem 0;}
.q{background:var(--panel); border:1px solid var(--line); border-radius:16px; box-shadow:var(--shadow); padding:1.1rem 1.2rem; margin:1rem 0;}
.q .qh{font-family:"Space Mono",monospace; font-size:.7rem; letter-spacing:.14em; text-transform:uppercase; color:var(--blue);}
.q .qt{font-weight:600; margin:.3rem 0 .9rem;}
.choices{display:grid; gap:.55rem;}
.choice{display:flex; gap:.7rem; align-items:flex-start; text-align:left; width:100%; cursor:pointer;
  border:1.5px solid var(--line); background:#fafbff; border-radius:12px; padding:.7rem .9rem; font:inherit; color:var(--ink); transition:all .12s;}
.choice:hover{border-color:var(--blue);}
.choice .lab{font-family:"Space Mono",monospace; font-weight:700; color:var(--blue); flex:0 0 auto;}
.choice.correct{border-color:var(--green); background:#e9f9f0;}
.choice.wrong{border-color:var(--coral); background:#ffeceA; background:#ffece9;}
.choice.correct .lab{color:var(--green);}
.choice.wrong .lab{color:var(--coral);}
.choice:disabled{cursor:default;}
.qfb{margin-top:.7rem; font-weight:700; font-family:"Sora",sans-serif; min-height:1.2em;}
.qfb.ok{color:var(--green);} .qfb.no{color:var(--coral);}
details.sol{margin-top:.7rem; border:1px solid var(--line); border-radius:10px; overflow:hidden;}
details.sol>summary{cursor:pointer; list-style:none; padding:.6rem .9rem; font-family:"Sora",sans-serif; font-weight:700; font-size:.85rem; background:#f2f4fd; color:var(--ink);}
details.sol>summary::-webkit-details-marker{display:none;}
details.sol .body{padding:.6rem .9rem .9rem; font-size:.95rem;}
.scorebar{position:sticky; bottom:0; background:var(--ink); color:#fff; border-radius:14px; padding:.8rem 1.1rem; margin-top:1.2rem;
  display:flex; align-items:center; gap:1rem; font-family:"Sora",sans-serif; font-weight:700; box-shadow:var(--shadow);}
.scorebar .big{font-size:1.4rem; color:var(--amber);}

/* glossary */
.glos{display:grid; grid-template-columns:repeat(auto-fit,minmax(230px,1fr)); gap:.8rem;}
.glos .term{background:var(--panel); border:1px solid var(--line); border-radius:12px; padding:.8rem .9rem;}
.glos .term b{font-family:"Sora",sans-serif;}
.glos .term span{display:block; color:var(--ink-soft); font-size:.9rem; margin-top:.2rem;}

/* lessons grid (home) */
.lessons{display:grid; grid-template-columns:repeat(auto-fill,minmax(250px,1fr)); gap:1.1rem; margin-top:1.4rem;}
.lcard{display:block; background:var(--panel); border:1px solid var(--line); border-radius:16px; box-shadow:var(--shadow); padding:1.2rem; transition:transform .15s, box-shadow .15s;}
.lcard:hover{transform:translateY(-3px); box-shadow:0 20px 44px rgba(22,26,46,.16); text-decoration:none;}
.lcard .tag{font-family:"Space Mono",monospace; font-size:.66rem; letter-spacing:.14em; text-transform:uppercase; color:var(--blue);}
.lcard h3{margin:.4rem 0 .3rem; font-size:1.25rem;}
.lcard p{color:var(--ink-soft); font-size:.92rem; margin:0;}
.lcard.soon{opacity:.6; pointer-events:none;}

@media (max-width:600px){
  body{font-size:16px;}
  .navlinks{font-size:.78rem; gap:.2rem .9rem;}
}
@media (prefers-reduced-motion:reduce){
  .brand .logo-poly{animation:none;}
  *{scroll-behavior:auto;}
}