/* ============================================================
   Physics Tracker — visual language
   Palette:  #12213B (deep indigo, primary)  #F6F4EE (parchment bg)
             #2F8F86 (teal, "read/done")      #E2A33D (amber, streak/focus)
             #C4553E (soft clay, gentle alert) #ffffff (card)
   Type: "Fraunces" (display, chapter numerals) / "Inter" (body/UI)
         / "JetBrains Mono" (data: streak count, %, section codes)
   Signature: the "spine" — each chapter renders as a vertical book
   spine that fills top-to-bottom with teal as sections are completed,
   echoing the physical NCERT volume this whole plan is built from.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Fraunces:opsz,wght@9..144,400;9..144,600;9..144,700&family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@500;600&display=swap');

:root{
  --ink:#12213B;
  --parchment:#F6F4EE;
  --card:#FFFFFF;
  --teal:#2F8F86;
  --teal-dim:#DCEDEA;
  --amber:#E2A33D;
  --amber-dim:#FBEAD0;
  --clay:#C4553E;
  --violet:#5B5A96;
  --violet-dim:#E7E6F2;
  --line:#E4DFD3;
  --text-soft:#5B6472;
  --radius:14px;
  --shadow:0 2px 10px rgba(18,33,59,0.06);
}

*{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%; scroll-behavior:smooth;}
body{
  margin:0;
  background:
    linear-gradient(rgba(228,223,211,0.5) 1px, transparent 1px) 0 0/40px 40px,
    linear-gradient(90deg, rgba(228,223,211,0.5) 1px, transparent 1px) 0 0/40px 40px,
    var(--parchment);
  color:var(--ink);
  font-family:'Inter',system-ui,sans-serif;
  line-height:1.5;
}
h1,h2,h3,.display{
  font-family:'Fraunces',serif;
  font-weight:600;
  letter-spacing:-0.01em;
  margin:0;
}
.mono{ font-family:'JetBrains Mono',monospace; }
a{ color:inherit; }

.topbar{
  display:flex; align-items:center; justify-content:space-between;
  padding:18px 28px;
  position:relative; z-index:1;
}
.topbar .brand{ font-family:'Fraunces',serif; font-size:1.25rem; font-weight:700; text-decoration:none; color:var(--parchment); }
.topbar .brand span{ color:var(--amber); }
.topbar .who{ font-size:0.9rem; opacity:0.85; }
.topbar a.logout{
  color:var(--parchment); text-decoration:none; font-size:0.85rem;
  border:1px solid rgba(246,244,238,0.35); padding:6px 12px; border-radius:20px;
}
.topbar a.logout:hover{ border-color:var(--amber); }

.physics-hero{
  position:relative; overflow:hidden; color:var(--parchment);
  background:
    radial-gradient(ellipse 70% 60% at 80% 0%, rgba(47,143,134,0.3), transparent),
    var(--ink);
}
.physics-hero-atom{ position:absolute; top:-10px; right:-10px; opacity:0.45; z-index:0; }
.physics-hero .formula-field span:nth-child(1){ top:20%; left:5%; font-size:1.1rem; transform:rotate(-6deg); }
.physics-hero .formula-field span:nth-child(2){ bottom:15%; left:20%; font-size:1rem; transform:rotate(4deg); }
.physics-hero .formula-field span:nth-child(3){ top:60%; left:45%; font-size:0.95rem; transform:rotate(-3deg); }
.physics-hero .formula-field span:nth-child(4){ top:15%; left:60%; font-size:1rem; transform:rotate(5deg); }

.wrap{ max-width:1080px; margin:0 auto; padding:28px 20px 60px; }

/* ---- stat strip ---- */
.stats{ display:grid; grid-template-columns:repeat(auto-fit,minmax(160px,1fr)); gap:14px; margin-bottom:30px; }
.stat{
  background:var(--card); border-radius:var(--radius); box-shadow:var(--shadow);
  padding:18px 20px;
}
.stat .num{ font-family:'JetBrains Mono',monospace; font-size:1.8rem; font-weight:600; }
.stat .label{ font-size:0.8rem; color:var(--text-soft); text-transform:uppercase; letter-spacing:0.05em; margin-top:2px; }
.stat.streak .num{ color:var(--amber); }
.stat.progress .num{ color:var(--teal); }

/* ---- chapter spine list ---- */
.chapter{
  display:flex; gap:16px;
  background:var(--card); border-radius:var(--radius); box-shadow:var(--shadow);
  margin-bottom:14px; padding:16px 18px;
}
.spine{
  flex:0 0 8px; border-radius:4px; background:var(--line); position:relative; overflow:hidden;
}
.spine .fill{
  position:absolute; bottom:0; left:0; width:100%; background:var(--teal);
  transition:height .4s ease;
}
.chapter-body{ flex:1; min-width:0; }
.chapter-head{ display:flex; align-items:baseline; justify-content:space-between; gap:10px; cursor:pointer; }
.chapter-head h3{ font-size:1.05rem; }
.chapter-head .num{ color:var(--text-soft); font-family:'JetBrains Mono',monospace; font-size:0.85rem; margin-right:8px; }
.chapter-head .pct{ font-family:'JetBrains Mono',monospace; color:var(--teal); font-weight:600; font-size:0.9rem; white-space:nowrap; }
.pdf-link{
  flex:none; font-size:0.78rem; text-decoration:none; color:var(--ink);
  border:1.5px solid var(--line); padding:5px 12px; border-radius:20px; white-space:nowrap;
}
.pdf-link:hover{ border-color:var(--teal); color:var(--teal); }
.part-tag{
  display:inline-block; font-size:0.68rem; text-transform:uppercase; letter-spacing:0.06em;
  background:var(--amber-dim); color:#8a5a12; padding:2px 8px; border-radius:20px; margin-bottom:4px;
}

.sections{ margin-top:12px; display:none; border-top:1px solid var(--line); padding-top:10px; }
.sections.open{ display:block; }
.section-row{
  display:flex; align-items:center; gap:12px; padding:8px 0; border-bottom:1px dashed var(--line);
  font-size:0.92rem;
}
.section-row:last-child{ border-bottom:none; }
.section-row .sn{ font-family:'JetBrains Mono',monospace; color:var(--text-soft); width:44px; flex:none; }
.section-row .st{ flex:1; min-width:0; }
.checks{ display:flex; gap:8px; flex:none; }
.chk{
  width:38px; height:38px; border-radius:10px; border:2px solid var(--line);
  display:flex; align-items:center; justify-content:center; cursor:pointer;
  font-size:0.95rem; font-weight:700; background:#fff; color:var(--text-soft); user-select:none;
  transition:all .15s ease; font-family:'JetBrains Mono',monospace;
}
.chk:hover{ transform:translateY(-1px); box-shadow:0 4px 10px rgba(18,33,59,0.12); }
.chk.r{ border-color:rgba(47,143,134,0.4); color:var(--teal); }
.chk.p{ border-color:rgba(91,90,150,0.4); color:var(--violet); }
.chk.v{ border-color:rgba(226,163,61,0.5); color:#8a5a12; }
.chk.r[data-on="1"]{ background:linear-gradient(135deg,var(--teal),#256f68); border-color:var(--teal); color:#fff; box-shadow:0 4px 14px rgba(47,143,134,0.45); }
.chk.p[data-on="1"]{ background:linear-gradient(135deg,var(--violet),#454379); border-color:var(--violet); color:#fff; box-shadow:0 4px 14px rgba(91,90,150,0.45); }
.chk.v[data-on="1"]{ background:linear-gradient(135deg,var(--amber),#c98826); border-color:var(--amber); color:#fff; box-shadow:0 4px 14px rgba(226,163,61,0.45); }
.chk.pop{ animation:chk-pop .35s ease; }
@keyframes chk-pop{
  0%{ transform:scale(1); }
  40%{ transform:scale(1.25); }
  100%{ transform:scale(1); }
}

.learn-btn{
  flex:none; font-family:'Inter',sans-serif; font-size:0.72rem; font-weight:600;
  color:var(--teal); background:var(--teal-dim); border:none; border-radius:20px;
  padding:5px 12px; cursor:pointer; letter-spacing:0.02em;
}
.learn-btn:hover{ background:var(--teal); color:#fff; }
.learn-btn.active{ background:var(--ink); color:var(--parchment); }
.learn-panel{
  display:none; background:var(--parchment); border:1px solid var(--line); border-radius:10px;
  padding:12px 14px; margin:2px 0 10px; font-size:0.88rem; line-height:1.6; color:var(--ink);
}
.learn-panel.open{ display:block; }
.learn-text{ margin-bottom:10px; }
.video-links{ display:flex; flex-wrap:wrap; gap:8px; margin-bottom:12px; }
.video-link{
  display:inline-block; font-size:0.8rem; text-decoration:none;
  padding:6px 12px; border-radius:20px; border:1px solid var(--line);
}
.video-link.generic{ color:var(--ink); background:#fff; }
.video-link.generic:hover{ border-color:var(--text-soft); }
.video-link.specific{ color:var(--teal); background:var(--teal-dim); border-color:transparent; font-weight:600; }
.video-link.specific:hover{ background:var(--teal); color:#fff; }
.doubt-box{ border-top:1px dashed var(--line); padding-top:10px; }
.doubt-input{
  width:100%; border:1.5px solid var(--line); border-radius:10px; padding:8px 10px;
  font-family:inherit; font-size:0.85rem; resize:vertical; background:#fff;
}
.doubt-input:focus{ outline:2px solid var(--clay); outline-offset:1px; border-color:var(--clay); }
.doubt-send{
  margin-top:6px; background:var(--clay); color:#fff; border:none; border-radius:20px;
  padding:6px 16px; font-size:0.8rem; font-weight:600; cursor:pointer; font-family:'Inter',sans-serif;
}
.doubt-send:hover{ opacity:0.9; }
.doubt-send:disabled{ opacity:0.6; cursor:default; }
.doubt-sent-msg{ display:none; margin-left:10px; font-size:0.8rem; color:var(--teal); font-weight:600; }
.doubt-sent-msg.show{ display:inline; }

/* ---- login ---- */
.login-wrap{
  min-height:100vh; display:flex; align-items:center; justify-content:center;
  position:relative; overflow:hidden; padding:20px;
  background:
    radial-gradient(ellipse 80% 50% at 50% -10%, rgba(47,143,134,0.25), transparent),
    var(--ink);
}
.login-wrap .atom{ position:absolute; top:50%; left:50%; transform:translate(-50%,-50%); opacity:0.4; z-index:0; }
.login-wrap .formula-field span:nth-child(1){ top:10%; left:8%; font-size:1.6rem; transform:rotate(-8deg); }
.login-wrap .formula-field span:nth-child(2){ bottom:12%; right:8%; font-size:1.5rem; transform:rotate(6deg); }
.login-card{
  background:rgba(246,244,238,0.97); backdrop-filter:blur(12px);
  border-radius:24px; padding:44px 36px; width:100%; max-width:380px;
  box-shadow:0 30px 80px rgba(0,0,0,0.45); position:relative; z-index:1;
}
.login-card h1{ font-family:'Fraunces',serif; font-size:1.9rem; font-weight:700; margin-bottom:6px; }
.login-card p.sub{ color:var(--text-soft); margin:0 0 26px; font-size:0.92rem; }
.field{ margin-bottom:16px; }
.field label{ display:block; font-size:0.8rem; color:var(--text-soft); margin-bottom:6px; }
.field input{
  width:100%; padding:10px 12px; border:1.5px solid var(--line); border-radius:10px;
  font-size:1rem; font-family:inherit; background:#fff;
}
.field input:focus{ outline:2px solid var(--teal); outline-offset:1px; border-color:var(--teal); }
button.primary{
  width:100%; padding:14px; border:none; border-radius:14px; background:var(--ink); color:#fff;
  font-size:1rem; font-weight:600; cursor:pointer; font-family:'Inter',sans-serif;
  transition:transform .2s ease, background .2s ease;
}
button.primary:hover{ background:var(--teal); transform:translateY(-1px); }
button.primary:active{ transform:translateY(0); }
.error-msg{ background:#FBEAE6; color:var(--clay); padding:10px 12px; border-radius:8px; font-size:0.85rem; margin-bottom:16px; }

/* ---- admin table ---- */
table.admin{ width:100%; border-collapse:collapse; background:var(--card); border-radius:var(--radius); overflow:hidden; box-shadow:var(--shadow); }
table.admin th, table.admin td{ padding:12px 16px; text-align:left; font-size:0.9rem; border-bottom:1px solid var(--line); }
table.admin th{ background:var(--ink); color:var(--parchment); font-weight:500; font-size:0.78rem; text-transform:uppercase; letter-spacing:0.04em; }
table.admin tr:last-child td{ border-bottom:none; }
.badge{ display:inline-block; padding:2px 10px; border-radius:20px; font-size:0.75rem; font-family:'JetBrains Mono',monospace; }
.badge.good{ background:var(--teal-dim); color:var(--teal); }
.badge.warn{ background:var(--amber-dim); color:#8a5a12; }
.badge.bad{ background:#FBEAE6; color:var(--clay); }

.legend{ font-size:0.8rem; color:var(--text-soft); margin:6px 0 20px; }
.legend .k{ font-weight:600; color:var(--ink); }

.doubts-list{ display:flex; flex-direction:column; gap:10px; }
.doubt-card{
  background:var(--card); border-radius:12px; padding:14px 16px; box-shadow:var(--shadow);
  border-left:4px solid var(--clay);
}
.doubt-card.resolved{ border-left-color:var(--teal); opacity:0.75; }
.doubt-meta{ font-size:0.75rem; color:var(--text-soft); margin-bottom:6px; }
.doubt-q{ font-size:0.95rem; margin-bottom:10px; }
.resolve-btn{
  background:var(--teal); color:#fff; border:none; border-radius:20px; padding:5px 14px;
  font-size:0.78rem; font-weight:600; cursor:pointer; font-family:'Inter',sans-serif;
}
.resolve-btn:hover{ opacity:0.9; }

/* ---- responsive layout, base rules (apply at all sizes, kick in naturally on narrow screens) ---- */
.chapter-head{ flex-wrap:wrap; row-gap:8px; }
.section-row{ flex-wrap:wrap; row-gap:8px; }
.section-row .sn{ order:0; }
.section-row .st{ order:1; flex:1 1 160px; min-width:0; }
.section-row .learn-btn{ order:2; }
.section-row .checks{ order:3; }

@media (max-width:600px){
  body{ font-size:15px; }
  .topbar{ padding:14px 16px; }
  .topbar .brand{ font-size:1.1rem; }
  .wrap{ padding:16px 12px 60px; }
  .stats{ grid-template-columns:1fr 1fr; gap:10px; }
  .stat{ padding:14px 16px; }
  .stat .num{ font-size:1.5rem; }
  .chapter{ padding:14px 14px; gap:12px; }
  .chapter-head > div:first-child{ flex:1 1 100%; }
  .pdf-link{ order:2; }
  .pct{ order:3; margin-left:auto; }
  .section-row .sn{ flex:0 0 auto; }
  .section-row .st{ flex:1 1 100%; order:1; }
  .section-row .learn-btn{ order:2; }
  .section-row .checks{ order:3; margin-left:auto; }
  .chk{ width:36px; height:36px; font-size:0.9rem; }
  .learn-btn{ padding:7px 14px; }
  .video-links{ flex-direction:column; align-items:flex-start; }
  .doubt-send{ width:100%; margin-top:8px; }
  .doubt-sent-msg{ display:block; margin-left:0; margin-top:6px; }
}

@media (max-width:400px){
  .stats{ grid-template-columns:1fr; }
}

/* ---- homepage ---- */
.home-body{
  background:
    radial-gradient(ellipse 80% 50% at 50% -10%, rgba(47,143,134,0.25), transparent),
    var(--ink);
}
.home-hero-wrap{ position:relative; overflow:hidden; padding:72px 20px 40px; text-align:center; }
.home-hero-wrap .formula-field span:nth-child(1){ top:8%; left:6%; font-size:1.8rem; transform:rotate(-8deg); }
.home-hero-wrap .formula-field span:nth-child(2){ top:18%; right:8%; font-size:1.4rem; transform:rotate(6deg); }
.home-hero-wrap .formula-field span:nth-child(3){ bottom:10%; left:10%; font-size:1.6rem; transform:rotate(5deg); }
.home-hero-wrap .formula-field span:nth-child(4){ bottom:20%; right:6%; font-size:1.3rem; transform:rotate(-6deg); }
.home-hero-wrap .formula-field span:nth-child(5){ top:45%; left:2%; font-size:1.2rem; transform:rotate(-4deg); }
.home-hero-wrap .formula-field span:nth-child(6){ top:50%; right:3%; font-size:1.5rem; transform:rotate(8deg); }
.home-hero-wrap .atom{ position:absolute; top:50%; left:50%; transform:translate(-50%,-50%); opacity:0.55; z-index:0; }

.home-wrap{ max-width:640px; margin:0 auto; padding:0 20px 60px; position:relative; z-index:1; }
.home-hero{ text-align:center; margin-bottom:28px; position:relative; z-index:1; }
.home-eyebrow{
  font-family:'JetBrains Mono',monospace; font-size:0.78rem; letter-spacing:0.14em;
  color:var(--amber); text-transform:uppercase; margin-bottom:14px;
}
.home-title{
  font-family:'Fraunces',serif; font-weight:700; color:var(--parchment);
  letter-spacing:-0.03em; margin-bottom:14px; line-height:1.02;
  font-size:clamp(2.6rem, 9vw, 4.6rem);
}
.home-title .accent{
  background:linear-gradient(100deg, var(--teal), var(--amber));
  -webkit-background-clip:text; background-clip:text; color:transparent;
}
.home-sub{ color:rgba(246,244,238,0.68); font-size:clamp(1rem, 3vw, 1.2rem); max-width:420px; margin:0 auto; }
.home-target-badge{
  display:inline-block; margin-top:18px; font-family:'JetBrains Mono',monospace; font-size:0.85rem;
  background:rgba(226,163,61,0.15); border:1px solid rgba(226,163,61,0.4); color:var(--amber);
  padding:7px 18px; border-radius:20px;
}
.home-quote{
  font-family:'Fraunces',serif; font-style:italic; font-size:1.15rem; line-height:1.6;
  color:var(--parchment); text-align:center; max-width:480px; margin:36px auto 32px;
  padding:0 12px; border:none; opacity:0.92; position:relative; z-index:1;
}
.home-card{
  background:var(--parchment); border-radius:20px; padding:26px 24px; margin-bottom:16px;
  box-shadow:0 20px 50px rgba(0,0,0,0.3); transition:transform .35s ease, box-shadow .35s ease;
}
.home-card:hover{ transform:translateY(-3px); box-shadow:0 26px 60px rgba(0,0,0,0.35); }
.home-card h2{ font-family:'Fraunces',serif; font-size:1.2rem; margin-bottom:14px; color:var(--ink); }
.home-steps{ list-style:none; counter-reset:step; padding:0; margin:0; }
.home-steps li{
  counter-increment:step; position:relative; padding-left:34px; margin-bottom:12px;
  font-size:0.92rem; line-height:1.55; color:var(--ink);
}
.home-steps li::before{
  content:counter(step); position:absolute; left:0; top:0;
  width:22px; height:22px; border-radius:50%; background:var(--teal); color:#fff;
  font-family:'JetBrains Mono',monospace; font-size:0.72rem; font-weight:600;
  display:flex; align-items:center; justify-content:center;
}
.home-steps li span{ font-weight:600; }
.home-steps li:last-child{ margin-bottom:0; }

.subject-grid{ display:grid; grid-template-columns:1fr; gap:10px; }
.subject-card{
  display:flex; align-items:center; justify-content:space-between; padding:16px 18px;
  border-radius:14px; text-decoration:none; border:1.5px solid var(--line);
  transition:transform .2s ease, box-shadow .2s ease;
}
.subject-card.live:hover{ transform:translateY(-2px) scale(1.01); box-shadow:0 10px 24px rgba(47,143,134,0.25); }
.subject-card.live{ background:var(--teal-dim); border-color:transparent; }
.subject-card.live .subject-name{ color:var(--ink); font-weight:700; }
.subject-card.live .subject-status{ color:var(--teal); font-weight:600; }
.subject-card.soon{ background:#fff; opacity:0.6; }
.subject-card.soon .subject-status{ color:var(--text-soft); }
.subject-name{ font-family:'Fraunces',serif; font-size:1.05rem; }
.subject-status{ font-family:'JetBrains Mono',monospace; font-size:0.75rem; }

.home-cta{ text-align:center; margin-top:32px; position:relative; z-index:1; }
.home-login-btn{
  display:inline-block; background:linear-gradient(100deg, var(--amber), #f0b355); color:var(--ink); font-weight:700;
  text-decoration:none; padding:16px 42px; border-radius:32px; font-size:1.05rem;
  box-shadow:0 10px 28px rgba(226,163,61,0.4); transition:transform .2s ease, box-shadow .2s ease;
}
.home-login-btn:hover{ transform:translateY(-2px) scale(1.03); box-shadow:0 14px 34px rgba(226,163,61,0.5); }
.home-login-btn:active{ transform:translateY(0) scale(0.98); }
.home-installtip{
  color:rgba(246,244,238,0.65); font-size:0.8rem; margin-top:18px; line-height:1.6;
  max-width:400px; margin-left:auto; margin-right:auto;
}
.login-home-link{
  display:inline-block; font-size:0.8rem; color:var(--text-soft); text-decoration:none; margin-bottom:14px;
}
.login-home-link:hover{ color:var(--teal); }

@media (max-width:480px){
  .home-title{ font-size:2.1rem; }
  .home-quote{ font-size:1rem; }
  .home-card{ padding:20px 16px; }
}

/* ============================================================
   Physics motif system — used on the homepage, login, and the
   top of the dashboard. Two building blocks:
   1. .atom — a CSS-only Bohr-model orbit animation (no images,
      no JS, works everywhere): a nucleus with three electron
      rings tilted at different angles, each electron travelling
      a true ellipse via a squash-then-spin nesting trick.
   2. .formula-field — scattered, low-opacity physics equations
      used as background texture, never as content.
   ============================================================ */

.atom{ position:relative; width:260px; height:260px; margin:0 auto; }
.atom .nucleus{
  position:absolute; top:50%; left:50%; width:16px; height:16px;
  background:var(--amber); border-radius:50%; transform:translate(-50%,-50%);
  box-shadow:0 0 24px 4px rgba(226,163,61,0.55);
  z-index:2;
}
.atom .orbit-tilt{ position:absolute; inset:0; }
.atom .orbit-squash{ position:absolute; inset:0; transform:scaleY(0.42); }
.atom .ring{
  position:absolute; inset:0; border:1.5px solid rgba(246,244,238,0.22);
  border-radius:50%;
}
.atom .spin{ position:absolute; inset:0; animation:atom-spin linear infinite; }
.atom .electron{
  position:absolute; top:-4px; left:50%; width:9px; height:9px; margin-left:-4.5px;
  border-radius:50%; background:var(--teal); box-shadow:0 0 12px 2px rgba(47,143,134,0.8);
}
.atom .orbit-2 .electron{ background:var(--amber); box-shadow:0 0 12px 2px rgba(226,163,61,0.8); }
.atom .orbit-3 .electron{ background:#fff; box-shadow:0 0 10px 2px rgba(255,255,255,0.7); }
.atom .orbit-1 .orbit-tilt{ transform:rotate(0deg); }
.atom .orbit-2 .orbit-tilt{ transform:rotate(60deg); }
.atom .orbit-3 .orbit-tilt{ transform:rotate(-60deg); }
.atom .orbit-1 .spin{ animation-duration:7s; }
.atom .orbit-2 .spin{ animation-duration:10s; animation-direction:reverse; }
.atom .orbit-3 .spin{ animation-duration:12s; }
@keyframes atom-spin{ from{ transform:rotate(0deg); } to{ transform:rotate(360deg); } }

.atom.small{ width:120px; height:120px; }
.atom.small .nucleus{ width:10px; height:10px; }
.atom.small .electron{ width:6px; height:6px; margin-left:-3px; }

.formula-field{ position:absolute; inset:0; overflow:hidden; pointer-events:none; z-index:0; }
.formula-field span{
  position:absolute; font-family:'Fraunces',serif; font-style:italic; font-weight:400;
  color:rgba(246,244,238,0.10); white-space:nowrap; user-select:none;
}
.formula-field.on-light span{ color:rgba(18,33,59,0.06); }

@keyframes fade-up{
  from{ opacity:0; transform:translateY(16px); }
  to{ opacity:1; transform:translateY(0); }
}
.reveal{ opacity:0; }
.reveal.in{ animation:fade-up 0.7s ease forwards; }

@media (prefers-reduced-motion: reduce){
  .atom .spin{ animation:none; }
  .reveal{ opacity:1; animation:none; }
}

/* ---- sub-navigation (Chapters / My Doubts) ---- */
.subnav{
  display:flex; gap:6px; padding:0 28px 16px; position:relative; z-index:1;
}
.subnav a{
  color:rgba(246,244,238,0.65); text-decoration:none; font-size:0.88rem; font-weight:600;
  padding:7px 16px; border-radius:20px; transition:all .15s ease; display:flex; align-items:center; gap:6px;
}
.subnav a:hover{ color:var(--parchment); }
.subnav a.active{ background:rgba(246,244,238,0.14); color:var(--parchment); }
.nav-badge{
  background:var(--clay); color:#fff; font-family:'JetBrains Mono',monospace; font-size:0.68rem;
  font-weight:700; padding:1px 7px; border-radius:10px; line-height:1.4;
}
.physics-hero.small-hero{ padding-bottom:2px; }

.stat.target .num{ color:var(--violet); }
.stat.target .of{ font-size:0.9rem; opacity:0.55; font-weight:400; }

/* ---- Doubts tab (student) ---- */
.doubt-card-full{
  background:var(--card); border-radius:14px; padding:18px 20px; margin-bottom:14px;
  box-shadow:var(--shadow); border-left:5px solid var(--clay);
}
.doubt-card-full.status-answered{ border-left-color:var(--amber); }
.doubt-card-full.status-cleared{ border-left-color:var(--teal); opacity:0.85; }
.doubt-meta{ font-size:0.75rem; color:var(--text-soft); margin-bottom:10px; }
.doubt-tag{
  display:inline-block; font-family:'JetBrains Mono',monospace; font-size:0.68rem; text-transform:uppercase;
  letter-spacing:0.05em; background:var(--line); color:var(--text-soft); padding:2px 8px; border-radius:6px;
  margin-right:8px; vertical-align:middle;
}
.doubt-tag.admin{ background:var(--teal-dim); color:var(--teal); }
.doubt-q-full{ font-size:1rem; line-height:1.6; margin-bottom:12px; }
.doubt-a-full{ font-size:1rem; line-height:1.6; background:var(--teal-dim); padding:14px 16px; border-radius:10px; margin-bottom:12px; }
.doubt-waiting{ font-size:0.85rem; color:var(--clay); font-style:italic; }
.clear-btn{
  background:var(--teal); color:#fff; border:none; border-radius:20px; padding:9px 20px;
  font-size:0.88rem; font-weight:700; cursor:pointer; font-family:'Inter',sans-serif;
  transition:transform .2s ease;
}
.clear-btn:hover{ transform:translateY(-1px); box-shadow:0 6px 16px rgba(47,143,134,0.35); }

/* ---- admin: response form + status states ---- */
.respond-form{ display:flex; flex-direction:column; gap:8px; margin-top:6px; }
.respond-form textarea{
  border:1.5px solid var(--line); border-radius:10px; padding:8px 10px; font-family:inherit;
  font-size:0.88rem; resize:vertical;
}
.doubt-a{ font-size:0.9rem; line-height:1.55; background:var(--teal-dim); padding:12px 14px; border-radius:10px; margin-bottom:8px; }
.doubt-card.status-answered{ border-left-color:var(--amber); }
.doubt-card.status-cleared{ border-left-color:var(--teal); opacity:0.8; }

/* ---- Learn modal (desktop only — triggered from JS at >=900px) ---- */
.learn-modal-overlay{
  display:none; position:fixed; inset:0; background:rgba(18,33,59,0.6); backdrop-filter:blur(4px);
  z-index:100; align-items:center; justify-content:center; padding:40px;
}
.learn-modal-overlay.open{ display:flex; }
.learn-modal{
  background:var(--parchment); border-radius:24px; max-width:680px; width:100%;
  max-height:85vh; overflow-y:auto; padding:44px 48px; position:relative;
  box-shadow:0 40px 100px rgba(0,0,0,0.4);
}
.learn-modal-close{
  position:absolute; top:20px; right:20px; width:36px; height:36px; border-radius:50%;
  border:none; background:var(--line); color:var(--ink); font-size:1rem; cursor:pointer;
}
.learn-modal-close:hover{ background:var(--clay); color:#fff; }
.learn-modal-title{
  font-family:'Fraunces',serif; font-size:1.7rem; font-weight:700; margin-bottom:20px; padding-right:40px;
}
.learn-modal-body{ font-size:1.15rem; line-height:1.8; }
.learn-modal-body .learn-text{ margin-bottom:18px; }
.learn-modal-body .video-links{ margin-bottom:20px; }
.learn-modal-body .video-link{ font-size:0.95rem; padding:9px 16px; }
.learn-modal-body .doubt-input{ font-size:1rem; }

@media (min-width:900px){
  .home-cards-desktop{ display:grid; grid-template-columns:1.1fr 0.9fr; gap:24px; align-items:start; }
  .home-title{ font-size:clamp(4rem, 6vw, 5.6rem); }
  .home-sub{ font-size:1.35rem; max-width:520px; }
  .home-quote{ font-size:1.4rem; max-width:640px; }
  .home-wrap{ max-width:1040px; }
  .home-card{ padding:32px 34px; }
  .home-card h2{ font-size:1.4rem; }
  .home-steps li{ font-size:1.02rem; }
  .subject-name{ font-size:1.15rem; }
}

/* ---- Worked examples (inside Learn panel / modal) ---- */
.examples-block{ margin:16px 0; }
.examples-heading{
  font-family:'Fraunces',serif; font-weight:700; font-size:1rem; margin-bottom:10px; color:var(--ink);
}
.example-card{
  background:#fff; border:1.5px solid var(--line); border-left:4px solid var(--violet);
  border-radius:10px; padding:12px 14px; margin-bottom:10px; font-size:0.9rem; line-height:1.55;
}
.example-label{
  font-family:'JetBrains Mono',monospace; font-size:0.7rem; text-transform:uppercase; letter-spacing:0.05em;
  color:var(--violet); font-weight:700; margin-bottom:6px;
}
.example-q{ margin-bottom:6px; }
.example-solve{ margin-bottom:6px; color:var(--text-soft); }
.example-answer{
  display:inline-block; background:var(--teal-dim); color:var(--teal); font-weight:700;
  padding:3px 12px; border-radius:20px; font-size:0.85rem; font-family:'JetBrains Mono',monospace;
}
.example-solution{ display:none; margin-top:10px; padding-top:10px; border-top:1px dashed var(--line); }
.example-solution.open{ display:block; }
.reveal-btn{
  display:block; width:100%; margin-top:10px; background:var(--violet-dim); color:var(--violet);
  border:1.5px dashed var(--violet); border-radius:8px; padding:9px 12px; font-size:0.85rem;
  font-weight:600; cursor:pointer; font-family:'Inter',sans-serif; transition:all .15s ease;
}
.reveal-btn:hover{ background:var(--violet); color:#fff; border-style:solid; }

/* Learn button badge for sections with worked examples */
.learn-btn.has-examples{ position:relative; padding-right:26px; }
.examples-dot{ position:absolute; top:-6px; right:-4px; font-size:0.8rem; }
.learn-modal-body .example-card{ font-size:1rem; padding:16px 18px; }
.learn-modal-body .examples-heading{ font-size:1.2rem; }

/* ---- Tests list ---- */
.test-list{ display:flex; flex-direction:column; gap:12px; }
.test-card{
  display:flex; align-items:center; justify-content:space-between; gap:16px;
  background:var(--card); border-radius:14px; padding:18px 20px; box-shadow:var(--shadow);
}
.test-card.soon{ opacity:0.55; }
.test-card h3{ font-size:1.05rem; margin:4px 0 4px; }
.test-meta{ font-size:0.85rem; color:var(--text-soft); }
.test-start-btn{
  flex:none; background:var(--violet); color:#fff; text-decoration:none; font-weight:700;
  padding:10px 22px; border-radius:24px; font-size:0.9rem; transition:transform .2s ease;
}
.test-start-btn:hover{ transform:translateY(-2px); box-shadow:0 8px 20px rgba(91,90,150,0.35); }
.test-start-btn.disabled{ background:var(--line); color:var(--text-soft); cursor:default; }

/* ---- Quiz taking page ---- */
.quiz-topbar{ background:var(--ink); color:var(--parchment); position:sticky; top:0; z-index:10; box-shadow:0 4px 16px rgba(0,0,0,0.15); }
.quiz-topbar-inner{ max-width:760px; margin:0 auto; padding:16px 20px; display:flex; align-items:center; justify-content:space-between; }
.quiz-topbar h2{ font-family:'Fraunces',serif; font-size:1.15rem; margin:2px 0 0; }
.timer-display{
  font-family:'JetBrains Mono',monospace; font-size:1.1rem; background:rgba(246,244,238,0.12);
  padding:8px 16px; border-radius:20px; white-space:nowrap;
}
.quiz-wrap{ max-width:760px; }
.quiz-question{ background:var(--card); border-radius:14px; padding:20px 22px; margin-bottom:16px; box-shadow:var(--shadow); }
.quiz-q-number{ font-family:'JetBrains Mono',monospace; font-size:0.75rem; color:var(--text-soft); text-transform:uppercase; letter-spacing:0.05em; margin-bottom:8px; }
.quiz-q-text{ font-size:1.05rem; font-weight:600; margin-bottom:16px; line-height:1.5; }
.quiz-options{ display:flex; flex-direction:column; gap:10px; }
.quiz-option{
  display:flex; align-items:flex-start; gap:12px; padding:12px 14px; border:1.5px solid var(--line);
  border-radius:10px; cursor:pointer; transition:all .15s ease;
}
.quiz-option:hover{ border-color:var(--violet); background:var(--violet-dim); }
.quiz-option input[type=radio]{ margin-top:3px; accent-color:var(--violet); width:16px; height:16px; }
.quiz-option:has(input:checked){ border-color:var(--violet); background:var(--violet-dim); }
.quiz-option-letter{
  font-family:'JetBrains Mono',monospace; font-weight:700; color:var(--violet); flex:none;
  width:22px; height:22px; display:flex; align-items:center; justify-content:center;
}
.quiz-option-text{ flex:1; font-size:0.95rem; }
.quiz-submit-btn{
  display:block; width:100%; background:var(--amber); color:var(--ink); border:none; border-radius:16px;
  padding:16px; font-size:1.1rem; font-weight:700; cursor:pointer; margin:20px 0 50px;
  box-shadow:0 10px 24px rgba(226,163,61,0.35); transition:transform .2s ease;
}
.quiz-submit-btn:hover{ transform:translateY(-2px); }

/* ---- Result page ---- */
.result-header{ margin-bottom:16px; }
.result-header h2{ font-family:'Fraunces',serif; font-size:1.4rem; margin-top:4px; }
.result-score-card{
  background:var(--ink); color:var(--parchment); border-radius:18px; padding:28px 24px;
  text-align:center; margin-bottom:28px;
}
.result-score-big{ font-family:'JetBrains Mono',monospace; font-size:3rem; font-weight:700; color:var(--amber); }
.result-score-big .of{ font-size:1.4rem; opacity:0.6; font-weight:400; }
.result-breakdown{ display:flex; justify-content:center; gap:18px; flex-wrap:wrap; margin-top:14px; font-size:0.9rem; font-family:'JetBrains Mono',monospace; }
.rb.correct{ color:var(--teal); }
.rb.wrong{ color:#e08070; }
.rb.skipped{ color:rgba(246,244,238,0.6); }
.rb.time{ color:var(--amber); }

.review-heading{ font-family:'Fraunces',serif; font-size:1.2rem; margin:24px 0 14px; }
.review-question{ background:var(--card); border-radius:14px; padding:18px 20px; margin-bottom:14px; box-shadow:var(--shadow); border-left:5px solid var(--line); }
.review-question.was-correct{ border-left-color:var(--teal); }
.review-question.was-wrong{ border-left-color:var(--clay); }
.review-question.was-skipped{ border-left-color:var(--text-soft); }
.review-options{ display:flex; flex-direction:column; gap:8px; margin:12px 0; }
.review-option{ display:flex; align-items:center; gap:10px; padding:10px 12px; border-radius:8px; border:1.5px solid var(--line); font-size:0.9rem; }
.review-option.is-correct-answer{ border-color:var(--teal); background:var(--teal-dim); }
.review-option.is-wrong-selected{ border-color:var(--clay); background:#FBEAE6; }
.review-tag{ margin-left:auto; font-size:0.7rem; font-family:'JetBrains Mono',monospace; text-transform:uppercase; color:var(--teal); font-weight:700; }
.review-tag.wrong{ color:var(--clay); }
.review-skipped-note{ font-size:0.85rem; font-style:italic; color:var(--text-soft); }
.review-explanation{ font-size:0.88rem; color:var(--text-soft); line-height:1.5; padding-top:8px; border-top:1px dashed var(--line); }

@media (max-width:600px){
  .quiz-topbar-inner{ padding:12px 16px; }
  .quiz-topbar h2{ font-size:1rem; }
  .timer-display{ font-size:0.95rem; padding:6px 12px; }
  .test-card{ flex-direction:column; align-items:flex-start; }
  .test-start-btn{ width:100%; text-align:center; }
  .result-score-big{ font-size:2.4rem; }
}

/* ---- standalone Worked Examples tab ---- */
.example-card.standalone{
  font-size:1rem; padding:20px 22px; margin-bottom:16px;
  border-left-width:5px;
}
.example-card.standalone .example-label{ font-size:0.78rem; margin-bottom:10px; }
.example-card.standalone .example-q{ font-size:1.05rem; margin-bottom:14px; }

/* ---- admin: worked examples batch toggles ---- */
.batch-card{
  display:flex; align-items:center; justify-content:space-between; gap:16px;
  background:var(--card); border-radius:12px; padding:14px 18px; box-shadow:var(--shadow);
  border-left:4px solid var(--line);
}
.batch-card.is-live{ border-left-color:var(--teal); }
.batch-name{ font-family:'Fraunces',serif; font-weight:700; font-size:1.02rem; }
.batch-toggle-btn{
  flex:none; background:var(--line); color:var(--text-soft); border:none; border-radius:20px;
  padding:9px 18px; font-size:0.85rem; font-weight:700; cursor:pointer; font-family:'Inter',sans-serif;
  transition:all .15s ease;
}
.batch-toggle-btn.on{ background:var(--teal); color:#fff; }
.batch-toggle-btn:hover{ opacity:0.85; }