/* =====================================================================
   369 Tesla CS PracticalVerse  —  style.css
   Global design system: tokens, layout, navbar, footer, buttons,
   cards, badges, forms, landing page, pricing, responsive.
   Brand: 369 Tesla | Kalviyogi   ·   Footer: Edunivra Pvt Ltd
   ===================================================================== */

:root{
  /* Brand gradient */
  --brand1:#7c3aed;     /* purple */
  --brand2:#2563eb;     /* blue   */
  --grad:linear-gradient(135deg,var(--brand1) 0%,var(--brand2) 100%);
  --grad-soft:linear-gradient(135deg,#f5f3ff 0%,#eff6ff 100%);

  /* Ink + neutrals */
  --ink:#0f172a;
  --ink-2:#334155;
  --muted:#64748b;
  --line:#e6e8f0;
  --bg:#ffffff;
  --bg-2:#f7f8fc;
  --white:#ffffff;

  /* States */
  --green:#16a34a;
  --green-bg:#f0fdf4;
  --amber:#d97706;
  --red:#dc2626;

  --radius:16px;
  --radius-sm:10px;
  --shadow:0 10px 30px rgba(15,23,42,.07);
  --shadow-lg:0 24px 60px rgba(15,23,42,.12);
  --maxw:1180px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:'Segoe UI',system-ui,-apple-system,Arial,sans-serif;
  color:var(--ink);
  background:var(--bg);
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
a{color:var(--brand2);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%}
h1,h2,h3,h4{line-height:1.2;margin:0 0 .5em}

.container{max-width:var(--maxw);margin:0 auto;padding:0 20px}
.section{padding:64px 0}
.section-tight{padding:40px 0}
.text-center{text-align:center}
.muted{color:var(--muted)}
.gradient-text{
  background:var(--grad);-webkit-background-clip:text;background-clip:text;
  -webkit-text-fill-color:transparent;
}

/* ---------- SVG icons ---------- */
.ic{display:inline-block;vertical-align:middle;flex:none}
.cs-ico{color:var(--brand1);line-height:0;vertical-align:middle}
.chip-link .cs-ico,.dash-nav .cs-ico,.badge .cs-ico{color:inherit}
.chip-link.active .cs-ico{color:#fff}
.subject-card .ico .cs-ico,.feature .ico .cs-ico{color:var(--brand1)}
.feature .ico{color:var(--brand1)}
.ico-inline{display:inline-flex;align-items:center;gap:7px}

/* ---------- Buttons ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  border:0;border-radius:12px;padding:12px 22px;font-size:15px;font-weight:700;
  cursor:pointer;text-decoration:none;transition:.18s transform,.18s box-shadow,.18s background;
  white-space:nowrap;
}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn-primary{background:var(--grad);color:#fff;box-shadow:0 8px 20px rgba(124,58,237,.28)}
.btn-dark{background:var(--ink);color:#fff}
.btn-dark:hover{background:#111827}
.btn-light{background:#fff;color:var(--ink);border:1px solid var(--line)}
.btn-ghost{background:transparent;color:#fff;border:1px solid rgba(255,255,255,.6)}
.btn-success{background:var(--green);color:#fff}
.btn-outline{background:#fff;color:var(--brand2);border:1px solid var(--brand2)}
.btn-sm{padding:8px 14px;font-size:13px;border-radius:10px}
.btn-block{width:100%}
.btn:disabled{opacity:.55;cursor:not-allowed;transform:none}

/* ---------- Badges ---------- */
.badge{display:inline-block;padding:3px 10px;border-radius:999px;font-size:12px;font-weight:700}
.badge-green{background:var(--green-bg);color:var(--green)}
.badge-amber{background:#fffbeb;color:var(--amber)}
.badge-red{background:#fef2f2;color:var(--red)}
.badge-gray{background:#f1f5f9;color:var(--muted)}
.badge-brand{background:#f5f3ff;color:var(--brand1)}

/* ---------- Alerts ---------- */
.alert{padding:12px 14px;border-radius:12px;font-size:14px;margin-bottom:14px;border:1px solid transparent}
.alert-error{background:#fef2f2;color:#b91c1c;border-color:#fecaca}
.alert-success{background:#f0fdf4;color:#166534;border-color:#bbf7d0}
.alert-info{background:#eff6ff;color:#1d4ed8;border-color:#bfdbfe}
.alert-warning{background:#fffbeb;color:#b45309;border-color:#fde68a}

/* ---------- Navbar ---------- */
.navbar{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);
  backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.navbar .container{display:flex;align-items:center;justify-content:space-between;height:66px}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;color:var(--ink)}
.brand:hover{text-decoration:none}
.brand .logo{width:40px;height:40px;border-radius:11px;display:grid;place-items:center;
  color:#fff;font-weight:900;font-size:14px;background:var(--grad);box-shadow:0 6px 16px rgba(124,58,237,.35)}
.brand .b-name{font-size:16px;line-height:1}
.brand .b-sub{font-size:11px;color:var(--muted);font-weight:600}
.nav-links{display:flex;align-items:center;gap:8px}
.nav-links a{color:var(--ink-2);font-weight:600;padding:8px 12px;border-radius:9px;font-size:14px}
.nav-links a:hover{background:var(--bg-2);text-decoration:none}
.nav-toggle{display:none;background:none;border:0;font-size:24px;cursor:pointer;color:var(--ink)}

/* ---------- Hero ---------- */
.hero{background:var(--grad-soft);border-bottom:1px solid var(--line);overflow:hidden}
.hero-grid{display:grid;grid-template-columns:1.1fr .9fr;gap:40px;align-items:center;padding:70px 0}
.hero h1{font-size:46px;letter-spacing:-1px}
.hero p.lead{font-size:18px;color:var(--ink-2);max-width:540px}
.hero .eyebrow{display:inline-block;background:#fff;border:1px solid var(--line);color:var(--brand1);
  font-weight:700;font-size:13px;padding:6px 14px;border-radius:999px;margin-bottom:18px}
.hero-cta{display:flex;gap:12px;flex-wrap:wrap;margin-top:26px}
.hero-stats{display:flex;gap:28px;margin-top:34px}
.hero-stats .num{font-size:26px;font-weight:800}
.hero-stats .lbl{font-size:13px;color:var(--muted)}

/* Hero illustration card */
.hero-card{background:#fff;border:1px solid var(--line);border-radius:22px;padding:22px;
  box-shadow:var(--shadow-lg)}
.hero-card .bar{height:10px;border-radius:6px;background:var(--grad);margin:6px 0;opacity:.9}
.hero-card .mini{display:flex;gap:8px;margin-top:14px;flex-wrap:wrap}
.hero-card .chip{font-size:12px;font-weight:700;padding:6px 10px;border-radius:8px;background:var(--bg-2);color:var(--ink-2)}
.code-line{font-family:'Consolas',monospace;font-size:13px;color:#475569;background:var(--bg-2);
  padding:6px 10px;border-radius:8px;margin:6px 0}

/* ---------- Cards / grids ---------- */
.grid{display:grid;gap:20px}
.grid-2{grid-template-columns:repeat(2,1fr)}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-4{grid-template-columns:repeat(4,1fr)}
.card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:24px;
  box-shadow:var(--shadow);transition:.18s transform,.18s box-shadow}
.card-hover:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg);text-decoration:none}

.feature .ico{width:48px;height:48px;border-radius:12px;display:grid;place-items:center;font-size:22px;
  background:var(--grad-soft);margin-bottom:14px}
.feature h3{font-size:17px}
.feature p{color:var(--muted);font-size:14px;margin:0}

/* Subject card */
.subject-card{display:block;color:inherit}
.subject-card .top{display:flex;align-items:center;gap:14px;margin-bottom:12px}
.subject-card .ico{width:54px;height:54px;border-radius:14px;display:grid;place-items:center;
  font-size:26px;background:var(--grad-soft)}
.subject-card h3{font-size:18px;margin:0}
.subject-card .count{font-size:13px;color:var(--muted)}
.subject-card p{color:var(--muted);font-size:14px;margin:0 0 8px}
.subject-card .go{color:var(--brand2);font-weight:700;font-size:14px}

/* Simulator card */
.sim-card{display:flex;flex-direction:column;gap:10px;color:inherit}
.sim-card .code{font-family:monospace;font-size:12px;color:var(--muted)}
.sim-card h3{font-size:16px;margin:0}
.sim-card p{color:var(--muted);font-size:13px;margin:0;flex:1}
.sim-card .row{display:flex;align-items:center;justify-content:space-between;margin-top:6px}

/* Section heading */
.sec-head{text-align:center;max-width:640px;margin:0 auto 40px}
.sec-head h2{font-size:32px}
.sec-head p{color:var(--muted);font-size:16px}

/* ---------- Steps (how it works) ---------- */
.steps{counter-reset:step}
.step{position:relative;padding-left:54px;margin-bottom:22px}
.step::before{counter-increment:step;content:counter(step);position:absolute;left:0;top:0;
  width:38px;height:38px;border-radius:11px;background:var(--grad);color:#fff;font-weight:800;
  display:grid;place-items:center}

/* ---------- Pricing ---------- */
.price-card{text-align:center;position:relative}
.price-card.popular{border:2px solid var(--brand1);box-shadow:var(--shadow-lg)}
.price-card .tag{position:absolute;top:-13px;left:50%;transform:translateX(-50%);
  background:var(--grad);color:#fff;font-size:12px;font-weight:700;padding:5px 14px;border-radius:999px}
.price-card .amt{font-size:40px;font-weight:800;margin:10px 0 2px}
.price-card .amt small{font-size:15px;color:var(--muted);font-weight:600}
.price-card ul{list-style:none;padding:0;margin:18px 0;text-align:left}
.price-card li{padding:7px 0;padding-left:26px;position:relative;color:var(--ink-2);font-size:14px}
.price-card li::before{content:"✓";position:absolute;left:0;color:var(--green);font-weight:800}

/* ---------- CTA band ---------- */
.cta-band{background:var(--grad);color:#fff;border-radius:24px;padding:48px;text-align:center}
.cta-band h2{color:#fff;font-size:30px}
.cta-band p{color:rgba(255,255,255,.9);max-width:560px;margin:0 auto 22px}

/* ---------- Footer ---------- */
.site-footer{background:#0b1020;color:#cbd5e1;margin-top:60px}
.site-footer .container{padding:50px 20px 26px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:30px}
.site-footer h4{color:#fff;font-size:14px;text-transform:uppercase;letter-spacing:.5px;margin-bottom:14px}
.site-footer a{color:#94a3b8;display:block;padding:4px 0;font-size:14px}
.site-footer a:hover{color:#fff}
.footer-brand .logo{width:40px;height:40px;border-radius:11px;display:grid;place-items:center;
  color:#fff;font-weight:900;background:var(--grad);margin-bottom:12px}
.footer-bottom{border-top:1px solid #1e293b;margin-top:34px;padding-top:20px;
  display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px;font-size:13px;color:#64748b}

/* ---------- Forms ---------- */
.form-row{margin-bottom:16px}
.form-row label{display:block;font-weight:600;font-size:14px;margin-bottom:6px;color:var(--ink-2)}
.input,select.input,textarea.input,
input[type=text],input[type=email],input[type=password],input[type=number],textarea,select{
  width:100%;padding:11px 13px;border:1px solid var(--line);border-radius:10px;font-size:14px;
  font-family:inherit;background:#fff;color:var(--ink)}
textarea{resize:vertical}
.input:focus,input:focus,textarea:focus,select:focus{outline:none;border-color:var(--brand2);
  box-shadow:0 0 0 3px rgba(37,99,235,.15)}

/* ---------- Tables ---------- */
.table{width:100%;border-collapse:collapse;font-size:14px;background:#fff}
.table th,.table td{padding:10px 12px;border-bottom:1px solid var(--line);text-align:left}
.table th{background:var(--bg-2);font-weight:700;color:var(--ink-2)}
.table tr:hover td{background:#fafbff}
.table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:12px}

/* ---------- Filter chips (subject/difficulty filter — public pages) ---------- */
.chips{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:12px}
.chip-link{display:inline-flex;align-items:center;gap:6px;padding:8px 14px;
  border-radius:999px;border:1px solid var(--line);background:#fff;
  font-size:13px;font-weight:600;color:var(--ink-2);cursor:pointer;
  text-decoration:none;transition:.15s border-color,.15s background,.15s color;
  white-space:nowrap;font-family:inherit}
.chip-link:hover{text-decoration:none;border-color:var(--brand2);color:var(--brand2)}
.chip-link.active{background:var(--grad);color:#fff;border-color:transparent}
.diff-chips .chip-link[data-diff="beginner"].active{background:var(--green);border-color:var(--green)}
.diff-chips .chip-link[data-diff="intermediate"].active{background:var(--amber);border-color:var(--amber)}
.diff-chips .chip-link[data-diff="advanced"].active{background:var(--red);border-color:var(--red)}

/* ---------- Utility ---------- */
.flex{display:flex}.items-center{align-items:center}.justify-between{justify-content:space-between}
.gap-10{gap:10px}.gap-16{gap:16px}.wrap{flex-wrap:wrap}
.mt-0{margin-top:0}.mt-10{margin-top:10px}.mt-20{margin-top:20px}.mt-30{margin-top:30px}
.mb-0{margin-bottom:0}.mb-20{margin-bottom:20px}
.hide{display:none}

/* ---------- Responsive ---------- */
@media (max-width:920px){
  .grid-4{grid-template-columns:repeat(2,1fr)}
  .grid-3{grid-template-columns:repeat(2,1fr)}
  .hero-grid{grid-template-columns:1fr}
  .hero h1{font-size:36px}
  .footer-grid{grid-template-columns:1fr 1fr}
}
@media (max-width:640px){
  .nav-links{position:absolute;top:66px;left:0;right:0;background:#fff;flex-direction:column;
    align-items:stretch;padding:10px;border-bottom:1px solid var(--line);box-shadow:var(--shadow);display:none}
  .nav-links.open{display:flex}
  .nav-links a{padding:12px}
  .nav-toggle{display:block}
  .grid-2,.grid-3,.grid-4{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr}
  .section{padding:44px 0}
  .hero h1{font-size:30px}
  .cta-band{padding:32px 20px}
}