/* EV MASTER LAB — design system
   Developed by Dr Bansilal Bairwa, REVA University */
@font-face{font-family:Inter;font-weight:400;src:url(../vendor/inter/inter-latin-400-normal.woff2) format('woff2');font-display:swap}
@font-face{font-family:Inter;font-weight:500;src:url(../vendor/inter/inter-latin-500-normal.woff2) format('woff2');font-display:swap}
@font-face{font-family:Inter;font-weight:600;src:url(../vendor/inter/inter-latin-600-normal.woff2) format('woff2');font-display:swap}
@font-face{font-family:Inter;font-weight:700;src:url(../vendor/inter/inter-latin-700-normal.woff2) format('woff2');font-display:swap}
@font-face{font-family:Inter;font-weight:800;src:url(../vendor/inter/inter-latin-800-normal.woff2) format('woff2');font-display:swap}

:root{
  --bg:#0a1020; --bg2:#0f1729; --panel:#131d33; --panel2:#18243f; --line:#24324f; --line2:#2f4066;
  --text:#e6ecf7; --muted:#93a3c0; --dim:#647596;
  --blue:#3b82f6; --cyan:#22d3ee; --green:#22c55e; --orange:#f59e0b; --red:#ef4444; --violet:#a78bfa; --pink:#f472b6; --yellow:#facc15;
  --accent:var(--cyan); --shadow:0 8px 30px rgba(0,0,0,.35);
  --radius:12px; --sidebar:290px; --header:60px;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  color-scheme:dark;
}
html.light{
  --bg:#f3f6fb; --bg2:#ffffff; --panel:#ffffff; --panel2:#f1f5fb; --line:#dbe3ef; --line2:#c7d3e5;
  --text:#0f1b33; --muted:#4b5d7d; --dim:#7a8aa6; --shadow:0 6px 24px rgba(15,27,51,.08);
  --cyan:#0891b2; --blue:#2563eb; --green:#16a34a; --orange:#d97706;
  color-scheme:light;
}
*{box-sizing:border-box}
html,body{margin:0;height:100%}
body{font-family:Inter,system-ui,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--text);font-size:14.5px;line-height:1.55;-webkit-font-smoothing:antialiased}
a{color:var(--cyan);text-decoration:none}a:hover{text-decoration:underline}
h1,h2,h3,h4{line-height:1.25;margin:.2em 0 .5em}
h1{font-size:1.75rem;font-weight:800;letter-spacing:-.02em}h2{font-size:1.3rem;font-weight:700}h3{font-size:1.06rem;font-weight:700}h4{font-size:.95rem;font-weight:600;color:var(--muted)}
p{margin:.4em 0 .8em}
code,.mono{font-family:var(--mono);font-size:.92em}
button,input,select{font:inherit;color:inherit}

/* ---------- header ---------- */
.hdr{position:fixed;inset:0 0 auto 0;height:var(--header);display:flex;align-items:center;gap:14px;padding:0 16px;background:linear-gradient(90deg,#0b1430,#0c1a3a 60%,#0b1430);border-bottom:1px solid var(--line);z-index:50}
html.light .hdr{background:linear-gradient(90deg,#0b1f4d,#123a7a)}
.brand{display:flex;align-items:center;gap:10px;color:#fff;min-width:0}
.brand .logo{width:36px;height:36px;border-radius:9px;background:conic-gradient(from 200deg,#22d3ee,#3b82f6,#22c55e,#22d3ee);display:grid;place-items:center;font-weight:900;color:#06122a;font-size:15px;box-shadow:0 0 18px rgba(34,211,238,.45)}
.brand b{font-size:1.05rem;letter-spacing:.06em;font-weight:800;white-space:nowrap}
.brand small{display:block;font-size:.7rem;color:#a9bbdc;white-space:nowrap}
.topnav{display:flex;gap:2px;margin-left:8px;overflow-x:auto;scrollbar-width:none;flex:1}
.topnav::-webkit-scrollbar{display:none}
.topnav a{color:#c6d3ee;padding:6px 8px;border-radius:8px;font-size:.8rem;font-weight:500;white-space:nowrap}
.topnav a:hover{background:rgba(255,255,255,.07);text-decoration:none}
.topnav a.on{background:rgba(34,211,238,.16);color:#fff}
.hdr-tools{display:flex;gap:6px;align-items:center}
.search{position:relative}
.search input{width:220px;background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.14);border-radius:9px;padding:7px 10px 7px 30px;color:#fff;outline:none}
.search input::placeholder{color:#9fb0cf}
.search svg{position:absolute;left:9px;top:9px;opacity:.7}
.sres{position:absolute;right:0;top:40px;width:420px;max-height:70vh;overflow:auto;background:var(--panel);border:1px solid var(--line2);border-radius:12px;box-shadow:var(--shadow);display:none;z-index:80}
.sres.on{display:block}
.sres a{display:block;padding:8px 12px;border-bottom:1px solid var(--line);color:var(--text)}
.sres a:hover{background:var(--panel2);text-decoration:none}
.sres small{color:var(--muted);display:block;font-size:.76rem}
.sres .sh{padding:6px 12px;font-size:.72rem;text-transform:uppercase;letter-spacing:.08em;color:var(--dim);background:var(--panel2)}
.ibtn{display:inline-grid;place-items:center;width:34px;height:34px;border-radius:9px;border:1px solid rgba(255,255,255,.14);background:rgba(255,255,255,.06);color:#e6ecf7;cursor:pointer}
.ibtn:hover{background:rgba(255,255,255,.14)}
.menu-btn{display:none}

/* ---------- layout ---------- */
.side{position:fixed;top:var(--header);left:0;bottom:0;width:var(--sidebar);background:var(--bg2);border-right:1px solid var(--line);overflow-y:auto;padding:12px 10px 40px;z-index:40}
.main{margin-left:var(--sidebar);padding-top:var(--header);min-height:100vh;display:flex;flex-direction:column}
.content{padding:22px 26px 30px;flex:1;max-width:1600px;width:100%}
.side h5{margin:14px 8px 6px;font-size:.7rem;letter-spacing:.12em;text-transform:uppercase;color:var(--dim)}
.unit{margin-bottom:4px;border-radius:10px}
.unit>button{width:100%;display:flex;align-items:center;gap:8px;text-align:left;background:none;border:0;padding:8px;border-radius:9px;cursor:pointer;color:var(--text);font-weight:600;font-size:.86rem}
.unit>button:hover{background:var(--panel2)}
.unit .uchip{min-width:26px;height:22px;border-radius:6px;display:grid;place-items:center;font-size:.72rem;font-weight:800;color:#06122a}
.unit .prog{margin-left:auto;font-size:.7rem;color:var(--muted);font-weight:500}
.unit ul{list-style:none;margin:2px 0 6px;padding:0 0 0 10px;display:none;border-left:1px solid var(--line);margin-left:20px}
.unit.open ul{display:block}
.unit li a{display:flex;gap:6px;padding:4px 8px;border-radius:7px;color:var(--muted);font-size:.8rem;line-height:1.35}
.unit li a:hover{background:var(--panel2);color:var(--text);text-decoration:none}
.unit li a.on{background:rgba(34,211,238,.14);color:var(--text)}
.unit li a .n{color:var(--dim);min-width:30px;font-family:var(--mono);font-size:.74rem;padding-top:1px}
.unit li a.done .n{color:var(--green)}
.unit li a.done::after{content:"✓";margin-left:auto;color:var(--green)}
.side .quick a{display:flex;align-items:center;gap:8px;padding:6px 8px;border-radius:8px;color:var(--muted);font-size:.84rem}
.side .quick a:hover{background:var(--panel2);color:var(--text);text-decoration:none}

/* ---------- footer (on every page) ---------- */
.foot{border-top:1px solid var(--line);background:var(--bg2);padding:16px 26px;display:flex;align-items:center;gap:14px;flex-wrap:wrap}
.foot img{width:46px;height:46px;border-radius:50%;object-fit:cover;object-position:50% 18%;border:2px solid var(--cyan)}
.foot .who{font-size:.86rem}
.foot .who b{color:var(--text)}
.foot .who span{color:var(--muted)}
.foot .li{display:inline-flex;align-items:center;gap:6px;background:#0a66c2;color:#fff;padding:6px 12px;border-radius:8px;font-weight:600;font-size:.82rem}
.foot .li:hover{text-decoration:none;filter:brightness(1.1)}
.foot .copy{margin-left:auto;color:var(--dim);font-size:.76rem;text-align:right}

/* ---------- generic ui ---------- */
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:16px;box-shadow:var(--shadow)}
.card.flat{box-shadow:none}
.grid{display:grid;gap:14px}
.g2{grid-template-columns:repeat(2,minmax(0,1fr))}.g3{grid-template-columns:repeat(3,minmax(0,1fr))}.g4{grid-template-columns:repeat(4,minmax(0,1fr))}
.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.btn{display:inline-flex;align-items:center;gap:6px;border:1px solid var(--line2);background:var(--panel2);padding:7px 12px;border-radius:9px;cursor:pointer;font-size:.84rem;font-weight:600;color:var(--text);white-space:nowrap}
.btn:hover{border-color:var(--cyan);text-decoration:none}
.btn.pri{background:linear-gradient(180deg,#2b8af7,#1f6fe0);border-color:#2b8af7;color:#fff}
.btn.go{background:linear-gradient(180deg,#22c55e,#16a34a);border-color:#22c55e;color:#04210f}
.btn.warn{background:rgba(245,158,11,.15);border-color:var(--orange)}
.btn.bad{background:rgba(239,68,68,.15);border-color:var(--red)}
.btn.sm{padding:4px 9px;font-size:.78rem}
.btn.on{background:rgba(34,211,238,.18);border-color:var(--cyan)}
.btn:disabled{opacity:.45;cursor:not-allowed}
.tag{display:inline-block;padding:2px 8px;border-radius:99px;font-size:.72rem;font-weight:600;background:var(--panel2);border:1px solid var(--line2);color:var(--muted)}
.tag.src{border-color:rgba(34,197,94,.5);color:var(--green)}
.tag.sup{border-color:rgba(245,158,11,.5);color:var(--orange)}
.tag.ill{border-color:rgba(167,139,250,.5);color:var(--violet)}
.muted{color:var(--muted)}.dim{color:var(--dim)}
.hr{height:1px;background:var(--line);margin:14px 0}
table.t{width:100%;border-collapse:collapse;font-size:.84rem}
table.t th,table.t td{padding:6px 9px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
table.t th{color:var(--muted);font-weight:600;background:var(--panel2);position:sticky;top:0}
table.t td.num,table.t th.num{text-align:right;font-variant-numeric:tabular-nums}
table.t tr:hover td{background:rgba(59,130,246,.05)}
.tblwrap{overflow:auto;max-height:420px;border:1px solid var(--line);border-radius:10px}
.note{border-left:3px solid var(--cyan);background:rgba(34,211,238,.07);padding:10px 12px;border-radius:0 8px 8px 0;margin:10px 0;font-size:.88rem}
.note.warn{border-color:var(--orange);background:rgba(245,158,11,.08)}
.note.ok{border-color:var(--green);background:rgba(34,197,94,.08)}
.note.bad{border-color:var(--red);background:rgba(239,68,68,.08)}

/* ---------- hero / home ---------- */
.hero{position:relative;overflow:hidden;border-radius:18px;padding:30px;background:radial-gradient(1200px 400px at 80% -10%,rgba(34,211,238,.22),transparent),radial-gradient(800px 380px at 0% 120%,rgba(59,130,246,.25),transparent),var(--panel);border:1px solid var(--line)}
.hero h1{font-size:2.2rem;margin:0 0 .2em}
.hero .sub{color:var(--muted);font-size:1.02rem;max-width:760px}
.hero canvas{position:absolute;right:0;top:0;height:100%;width:52%;opacity:.95;pointer-events:none}
.stat{background:var(--panel2);border:1px solid var(--line);border-radius:12px;padding:12px 14px}
.stat b{display:block;font-size:1.5rem;font-weight:800}
.stat span{color:var(--muted);font-size:.8rem}
.ucard{display:block;color:var(--text);border-radius:14px;padding:16px;border:1px solid var(--line);background:var(--panel);transition:transform .15s,border-color .15s}
.ucard:hover{transform:translateY(-2px);border-color:var(--cyan);text-decoration:none}
.ucard .bar{height:6px;border-radius:9px;background:var(--panel2);overflow:hidden;margin-top:10px}
.ucard .bar i{display:block;height:100%;background:linear-gradient(90deg,var(--cyan),var(--green))}
.expcard{display:flex;flex-direction:column;gap:4px;padding:12px;border:1px solid var(--line);border-radius:12px;background:var(--panel);color:var(--text)}
.expcard:hover{border-color:var(--cyan);text-decoration:none}
.expcard .id{font-family:var(--mono);font-size:.74rem;color:var(--cyan)}
.expcard.done{border-color:rgba(34,197,94,.45)}

/* ---------- experiment page ---------- */
.exphead{display:flex;gap:14px;align-items:flex-start;flex-wrap:wrap;margin-bottom:10px}
.exphead .eid{font-family:var(--mono);background:rgba(34,211,238,.14);color:var(--cyan);padding:4px 10px;border-radius:8px;font-weight:700}
.exphead h1{margin:0;font-size:1.5rem}
.crumbs{font-size:.8rem;color:var(--dim);margin-bottom:6px}
.crumbs a{color:var(--muted)}
.tabs{display:flex;gap:4px;border-bottom:1px solid var(--line);margin:8px 0 14px;overflow-x:auto}
.tabs button{background:none;border:0;border-bottom:2px solid transparent;padding:9px 13px;cursor:pointer;color:var(--muted);font-weight:600;font-size:.86rem;white-space:nowrap}
.tabs button.on{color:var(--text);border-color:var(--cyan)}
.toolbar{position:sticky;top:var(--header);z-index:30;display:flex;gap:6px;align-items:center;flex-wrap:wrap;padding:8px 10px;background:color-mix(in srgb,var(--panel) 92%,transparent);backdrop-filter:blur(8px);border:1px solid var(--line);border-radius:12px;margin-bottom:12px}
.toolbar .sep{width:1px;height:24px;background:var(--line2);margin:0 4px}
.toolbar label{font-size:.76rem;color:var(--muted);display:flex;align-items:center;gap:5px}
.toolbar select{background:var(--panel2);border:1px solid var(--line2);border-radius:7px;padding:4px 6px}
.toolbar .clock{font-family:var(--mono);font-size:.82rem;color:var(--cyan);margin-left:auto;padding:4px 8px;background:var(--panel2);border-radius:7px}
.lab{display:grid;grid-template-columns:300px minmax(0,1fr);gap:14px;align-items:start}
.ctrls{position:sticky;top:calc(var(--header) + 70px);max-height:calc(100vh - var(--header) - 90px);overflow:auto}
.ctrl{margin-bottom:11px}
.ctrl .lbl{display:flex;justify-content:space-between;font-size:.8rem;color:var(--muted);margin-bottom:3px;gap:6px}
.ctrl .lbl b{color:var(--text);font-weight:600;font-variant-numeric:tabular-nums;white-space:nowrap}
.ctrl input[type=range]{width:100%;accent-color:var(--cyan)}
.ctrl select,.ctrl input[type=number],.ctrl input[type=text]{width:100%;background:var(--panel2);border:1px solid var(--line2);border-radius:8px;padding:6px 8px}
.ctrl .chk{display:flex;gap:8px;align-items:center;font-size:.84rem;cursor:pointer}
.ctrl .seg{display:flex;flex-wrap:wrap;gap:4px}
.ctrl .seg button{flex:1 1 28%;min-width:0;padding:5px 4px;line-height:1.2;border-radius:7px;border:1px solid var(--line2);background:var(--panel2);cursor:pointer;font-size:.78rem;font-weight:600}
.ctrl .seg button.on{background:rgba(34,211,238,.2);border-color:var(--cyan)}
.ctrls h4{margin:14px 0 8px;padding-top:10px;border-top:1px solid var(--line)}
.ctrls h4:first-child{border:0;margin-top:0;padding-top:0}
.stage{position:relative;background:radial-gradient(900px 300px at 50% 0%,rgba(59,130,246,.08),transparent),var(--bg2);border:1px solid var(--line);border-radius:12px;overflow:hidden}
.stage canvas.anim{display:block;width:100%;height:420px}
.stage .hint{position:absolute;left:10px;bottom:8px;font-size:.72rem;color:var(--dim);pointer-events:none}
.stage .badge{position:absolute;right:10px;top:10px}
.stage.fs{position:fixed;inset:0;z-index:200;border-radius:0}
.stage.fs canvas.anim,.stage.fs .v3d{height:100vh!important}
.v3d{width:100%;height:440px;display:block;position:relative}
.v3d canvas{display:block}
.kpis{display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:8px;margin:12px 0}
.kpi{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:8px 10px;min-width:0}
.kpi span{display:block;font-size:.72rem;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.kpi b.sm{font-size:.9rem}
.kpi b{font-size:1.12rem;font-weight:700;font-variant-numeric:tabular-nums}
.kpi i{font-style:normal;color:var(--dim);font-size:.75rem;margin-left:3px}
.kpi.good b{color:var(--green)}.kpi.warn b{color:var(--orange)}.kpi.bad b{color:var(--red)}.kpi.acc b{color:var(--cyan)}
.charts{display:grid;grid-template-columns:repeat(auto-fill,minmax(420px,1fr));gap:12px}
.chart{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:8px 10px 6px;position:relative;min-width:0}
.chart h5{margin:2px 0 4px;font-size:.8rem;font-weight:600;color:var(--muted);display:flex;justify-content:space-between;align-items:center}
.chart h5 .acts{display:flex;gap:4px}
.chart h5 .acts button{background:none;border:1px solid var(--line2);border-radius:6px;padding:0 6px;font-size:.7rem;color:var(--muted);cursor:pointer}
.chart canvas{width:100%;height:240px;display:block}
.chart.tall canvas{height:320px}
.chart .tip{position:absolute;pointer-events:none;background:rgba(10,16,32,.92);color:#e6ecf7;border:1px solid var(--line2);border-radius:8px;padding:6px 8px;font-size:.74rem;display:none;white-space:nowrap;z-index:5;font-family:var(--mono)}
.eq{background:var(--panel2);border:1px solid var(--line);border-radius:10px;padding:10px 12px;margin:8px 0;overflow-x:auto}
.eq .d{font-size:.8rem;color:var(--muted);margin-top:4px}
.theory p,.theory li{max-width:900px}
.theory ul{padding-left:20px}
.steps li{margin-bottom:8px}
.mcq{border:1px solid var(--line);border-radius:10px;padding:12px;margin-bottom:10px;background:var(--panel)}
.mcq .q{font-weight:600;margin-bottom:8px}
.mcq label{display:flex;gap:8px;padding:6px 8px;border-radius:8px;cursor:pointer;border:1px solid transparent}
.mcq label:hover{background:var(--panel2)}
.mcq label.right{border-color:var(--green);background:rgba(34,197,94,.1)}
.mcq label.wrong{border-color:var(--red);background:rgba(239,68,68,.1)}
.mcq .ex{font-size:.84rem;color:var(--muted);margin-top:6px;display:none}
.mcq.answered .ex{display:block}
.pdfwrap{display:grid;grid-template-columns:280px 1fr;gap:12px;height:calc(100vh - var(--header) - 160px);min-height:520px}
.pdfwrap iframe{width:100%;height:100%;border:1px solid var(--line);border-radius:10px;background:#fff}
.pdfnav{overflow:auto;border:1px solid var(--line);border-radius:10px;background:var(--panel)}
.pdfnav a{display:flex;gap:8px;padding:5px 10px;font-size:.8rem;color:var(--muted);border-bottom:1px solid var(--line)}
.pdfnav a:hover{background:var(--panel2);color:var(--text);text-decoration:none}
.pdfnav a .n{font-family:var(--mono);color:var(--dim);min-width:46px}
.pdfnav a.l2{padding-left:22px}
.pdfnav a .pg{margin-left:auto;color:var(--dim);font-size:.72rem}
.toast{position:fixed;right:18px;bottom:18px;background:var(--panel);border:1px solid var(--cyan);padding:10px 14px;border-radius:10px;box-shadow:var(--shadow);z-index:300;font-size:.86rem;animation:fadein .2s}
@keyframes fadein{from{opacity:0;transform:translateY(8px)}}
.modal{position:fixed;inset:0;background:rgba(3,7,18,.6);display:grid;place-items:center;z-index:250}
.modal .card{max-width:720px;width:92vw;max-height:84vh;overflow:auto}
.dash{display:grid;grid-template-columns:repeat(auto-fill,minmax(118px,1fr));gap:7px}
.gauge{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:6px;text-align:center}
.gauge canvas{width:100%;height:120px}
.pedal{user-select:none;touch-action:none}
.kbd{font-family:var(--mono);background:var(--panel2);border:1px solid var(--line2);border-bottom-width:2px;border-radius:5px;padding:0 5px;font-size:.76rem}
.ok-t{color:var(--green);font-weight:700}.bad-t{color:var(--red);font-weight:700}.warn-t{color:var(--orange);font-weight:700}
.pill{display:inline-flex;gap:4px;align-items:center;padding:3px 9px;border-radius:99px;font-size:.74rem;font-weight:700}
.pill.ok{background:rgba(34,197,94,.15);color:var(--green)}.pill.bad{background:rgba(239,68,68,.15);color:var(--red)}.pill.warn{background:rgba(245,158,11,.15);color:var(--orange)}.pill.info{background:rgba(34,211,238,.15);color:var(--cyan)}
.calcgrid{display:grid;grid-template-columns:260px 1fr;gap:14px}
.calclist a{display:block;padding:7px 10px;border-radius:8px;color:var(--muted);font-size:.84rem}
.calclist a.on,.calclist a:hover{background:var(--panel2);color:var(--text);text-decoration:none}
.fault{display:flex;align-items:center;gap:8px;padding:6px 8px;border-radius:8px;border:1px solid var(--line);margin-bottom:5px;font-size:.82rem}
.fault.act{border-color:var(--red);background:rgba(239,68,68,.1)}
.loading{padding:40px;text-align:center;color:var(--muted)}
.katex{font-size:1.06em}
.katex-display{margin:.4em 0}

@media (max-width:1680px){.brand small{display:none}.search input{width:170px}}
@media (max-width:1500px){.search input{width:130px}.topnav a{padding:5px 6px;font-size:.77rem}}
@media (max-width:1100px){
  .lab{grid-template-columns:1fr}
  .ctrls{position:static;max-height:none}
  .g4{grid-template-columns:repeat(2,minmax(0,1fr))}
  .search input{width:150px}
}
@media (max-width:860px){
  .side{transform:translateX(-100%);transition:transform .2s;box-shadow:var(--shadow)}
  body.navopen .side{transform:none}
  .main{margin-left:0}
  .menu-btn{display:inline-grid}
  .topnav{display:none}
  .g2,.g3{grid-template-columns:1fr}
  .charts{grid-template-columns:1fr}
  .content{padding:14px}
  .pdfwrap,.calcgrid{grid-template-columns:1fr}
  .brand small{display:none}
  .hero canvas{opacity:.25;width:100%}
  .sres{width:88vw;right:-60px}
}
@media print{
  .hdr,.side,.toolbar,.foot .li{display:none!important}
  .main{margin:0;padding:0}
}
/* Live simulator layout (moved from inline style so the mobile breakpoint can stack it) */
.lab.simlab{grid-template-columns:300px minmax(0,1fr)}
.lab.simlab>*{min-width:0}
@media (max-width:860px){.lab.simlab{grid-template-columns:minmax(0,1fr)}}