/* ============================================================
   BrainBit Teaching · AI APIs in Django
   Interactive tutorial deck — visual system shared with the
   BCA AI/ML pitch deck, extended with code-card components.
   100% offline · no external requests.
   Navigation: → / Space / click = next · ← = prev · F = fullscreen
               O or Esc = slide overview · Home / End = first / last
   ============================================================ */

:root{
  --bg:#070b1e;
  --bg2:#0b1230;
  --ink:#0b1020;
  --indigo:#4f46e5;
  --blue:#2563eb;
  --cyan:#22d3ee;
  --sky:#38bdf8;
  --magenta:#d946ef;
  --violet:#8b5cf6;
  --emerald:#10b981;
  --amber:#f59e0b;
  --rose:#fb7185;
  --orange:#fb923c;
  --pink:#ec4899;
  --paper:#f6f8ff;
  --paper-ink:#0d1430;
  --muted:#64708f;

  --font-display:"Bahnschrift","Segoe UI Variable Display","Segoe UI Semibold","Segoe UI",system-ui,sans-serif;
  --font-body:"Segoe UI Variable Text","Segoe UI",system-ui,-apple-system,sans-serif;
  --font-mono:"Cascadia Code","Cascadia Mono","Consolas",ui-monospace,monospace;

  --r:22px;
}

*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{
  font-family:var(--font-body);
  background:var(--bg);
  color:#eaf0ff;
  overflow:hidden;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

/* ---------- Deck & slides ---------- */
#deck{position:fixed;inset:0}
.slide{
  position:absolute;inset:0;
  display:flex;flex-direction:column;justify-content:center;
  padding:4.6vh 7vw 8vh;
  opacity:0;visibility:hidden;
  transform:scale(.985);
  transition:opacity .55s ease, transform .55s ease, visibility .55s;
  overflow:hidden;
}
.slide.active{opacity:1;visibility:visible;transform:none;z-index:2}
.slide.prev{transform:scale(1.015)}

/* Light vs dark slide skins */
.slide.light{background:
  radial-gradient(1100px 700px at 12% -10%, rgba(79,70,229,.10), transparent 60%),
  radial-gradient(900px 700px at 110% 120%, rgba(34,211,238,.12), transparent 55%),
  linear-gradient(180deg,#ffffff, #eef2ff);
  color:var(--paper-ink);
}
.slide.dark{background:
  radial-gradient(1200px 800px at 18% 8%, rgba(79,70,229,.42), transparent 55%),
  radial-gradient(1000px 760px at 92% 18%, rgba(217,70,239,.30), transparent 52%),
  radial-gradient(1100px 900px at 70% 110%, rgba(34,211,238,.30), transparent 55%),
  linear-gradient(180deg,#05081a,#0a1130 60%,#05081a);
  color:#eef2ff;
}

/* Floating mesh blobs for dark slides */
.slide.dark::before{
  content:"";position:absolute;inset:-20% -10%;z-index:0;
  background:
    radial-gradient(closest-side, rgba(56,189,248,.5), transparent) 12% 28%/38vmax 38vmax no-repeat,
    radial-gradient(closest-side, rgba(217,70,239,.42), transparent) 86% 24%/34vmax 34vmax no-repeat,
    radial-gradient(closest-side, rgba(99,102,241,.45), transparent) 60% 96%/40vmax 40vmax no-repeat;
  filter:blur(8px);
  animation:drift 18s ease-in-out infinite alternate;
  opacity:.7;
}
@keyframes drift{
  0%{transform:translate3d(0,0,0) scale(1)}
  50%{transform:translate3d(-3%,2%,0) scale(1.06)}
  100%{transform:translate3d(2%,-2%,0) scale(1.02)}
}

/* Grain overlay */
.slide::after{
  content:"";position:absolute;inset:0;z-index:1;pointer-events:none;opacity:.05;
  background-image:url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/></filter><rect width='100%25' height='100%25' filter='url(%23n)'/></svg>");
  mix-blend-mode:overlay;
}
.slide>*{position:relative;z-index:3}

/* ---------- Reveal animation ---------- */
.anim{opacity:0;transform:translateY(26px);
  transition:opacity .6s cubic-bezier(.2,.75,.2,1), transform .6s cubic-bezier(.2,.75,.2,1);
  transition-delay:var(--d,0s);}
.slide.active .anim{opacity:1;transform:none}
.anim.left{transform:translateX(-30px)}
.anim.scale{transform:scale(.9)}

/* ---------- Typography ---------- */
.kicker{
  font-family:var(--font-mono);font-size:clamp(.7rem,1.1vw,.95rem);
  letter-spacing:.32em;text-transform:uppercase;font-weight:600;
  display:inline-flex;align-items:center;gap:.7em;
}
.kicker::before{content:"";width:34px;height:2px;background:linear-gradient(90deg,var(--cyan),var(--magenta))}
h1{font-family:var(--font-display);font-weight:700;line-height:.98;letter-spacing:-.5px}
h2{font-family:var(--font-display);font-weight:700;line-height:1.02;letter-spacing:-.4px;
   font-size:clamp(1.9rem,4.4vw,3.7rem)}
h3{font-family:var(--font-display);font-weight:600;letter-spacing:-.2px}
p{line-height:1.55}
.lead{font-size:clamp(1.02rem,1.6vw,1.42rem);line-height:1.5;max-width:62ch}
.grad{background:linear-gradient(110deg,var(--sky),var(--cyan) 40%,var(--magenta));
  -webkit-background-clip:text;background-clip:text;color:transparent}
.grad2{background:linear-gradient(110deg,var(--indigo),var(--violet) 50%,var(--pink));
  -webkit-background-clip:text;background-clip:text;color:transparent}

/* ---------- Chrome (top progress + bottom bar) ---------- */
#bar{position:fixed;top:0;left:0;height:5px;z-index:50;
  background:linear-gradient(90deg,var(--indigo),var(--cyan) 50%,var(--magenta));
  width:0;transition:width .5s cubic-bezier(.2,.8,.2,1);
  box-shadow:0 0 18px rgba(34,211,238,.7)}
#chrome{position:fixed;left:0;right:0;bottom:0;z-index:50;
  display:flex;align-items:center;justify-content:space-between;
  padding:14px 26px;pointer-events:none;
  font-family:var(--font-mono);font-size:.78rem;letter-spacing:.12em}
#brandmark{display:flex;align-items:center;gap:10px;opacity:.92;pointer-events:auto}
#brandmark .logo{width:24px;height:24px;border-radius:7px;
  background:#fff url(../../../../assets/logo-mark-64.png) center/contain no-repeat;
  box-shadow:0 0 0 1px rgba(0,0,0,.08)}
#brandmark b{font-family:var(--font-display);letter-spacing:.5px;font-weight:700}
#nav{display:flex;align-items:center;gap:10px;pointer-events:auto}
.btn{pointer-events:auto;cursor:pointer;border:none;color:inherit;
  width:38px;height:38px;border-radius:11px;font-size:1rem;
  display:grid;place-items:center;
  background:rgba(127,142,200,.16);backdrop-filter:blur(8px);
  border:1px solid rgba(160,175,230,.22);transition:.2s}
.btn:hover{background:rgba(127,142,200,.3);transform:translateY(-2px)}
#count{min-width:74px;text-align:center;opacity:.85}
#hint{position:fixed;bottom:64px;right:26px;z-index:50;font-family:var(--font-mono);
  font-size:.68rem;letter-spacing:.1em;opacity:.45;text-align:right;pointer-events:none;line-height:1.7}

/* ---------- Reusable pieces ---------- */
.card{background:rgba(255,255,255,.55);border:1px solid rgba(80,100,180,.18);
  border-radius:var(--r);padding:1.4rem 1.5rem;backdrop-filter:blur(6px);
  box-shadow:0 22px 50px -28px rgba(20,30,80,.5)}
.slide.dark .card{background:rgba(255,255,255,.06);border-color:rgba(160,180,255,.16);
  box-shadow:0 30px 60px -30px rgba(0,0,0,.7)}
.glass{background:rgba(255,255,255,.07);border:1px solid rgba(170,190,255,.18);
  border-radius:var(--r);backdrop-filter:blur(10px)}
.slide.light .glass{background:rgba(255,255,255,.5);border-color:rgba(80,100,180,.16)}
.chip{display:inline-flex;align-items:center;gap:.5em;font-family:var(--font-mono);
  font-size:.74rem;letter-spacing:.06em;padding:.42em .85em;border-radius:999px;
  border:1px solid currentColor;font-weight:600}
.pill{display:inline-flex;align-items:center;gap:.5em;padding:.4em .9em;border-radius:999px;
  font-size:.8rem;font-weight:600;font-family:var(--font-mono);letter-spacing:.05em}
.tag-stack{display:flex;flex-wrap:wrap;gap:.4rem}
.tag{font-family:var(--font-mono);font-size:.72rem;padding:.3em .65em;border-radius:8px;
  background:rgba(99,102,241,.14);border:1px solid rgba(99,102,241,.3);color:#c7d2fe}
.slide.light .tag{background:rgba(37,99,235,.08);border-color:rgba(37,99,235,.22);color:#1e3a8a}

.grid{display:grid;gap:1.1rem}
.section-no{font-family:var(--font-display);font-weight:700;font-size:clamp(4rem,11vw,9rem);
  line-height:.8;background:linear-gradient(180deg,rgba(255,255,255,.95),rgba(120,150,255,.25));
  -webkit-background-clip:text;background-clip:text;color:transparent;opacity:.85}

.stat{font-family:var(--font-display);font-weight:700;font-size:clamp(2.2rem,5vw,4rem);line-height:1}
mark{background:linear-gradient(transparent 58%, rgba(34,211,238,.45) 58%);color:inherit;padding:0 .1em}
.slide.dark mark{background:linear-gradient(transparent 58%, rgba(217,70,239,.5) 58%)}

ul.clean{list-style:none;display:grid;gap:.6rem}
ul.clean li{display:flex;gap:.7rem;align-items:flex-start;line-height:1.45}
ul.clean li::before{content:"▸";color:var(--cyan);font-weight:700;margin-top:.05em}
.slide.light ul.clean li::before{color:var(--blue)}

/* keycap */
kbd{font-family:var(--font-mono);font-size:.82em;padding:.12em .5em;border-radius:6px;
  background:rgba(99,102,241,.16);border:1px solid rgba(99,102,241,.4);
  box-shadow:0 2px 0 rgba(99,102,241,.35)}

/* table */
.tbl{width:100%;border-collapse:collapse;font-size:clamp(.72rem,1.05vw,.95rem)}
.tbl th{font-family:var(--font-mono);font-size:.68rem;letter-spacing:.14em;text-transform:uppercase;
  text-align:left;padding:.55rem .7rem;color:var(--muted);border-bottom:2px solid rgba(99,102,241,.3)}
.tbl td{padding:.5rem .7rem;border-bottom:1px solid rgba(99,102,241,.12)}
.tbl tr:hover td{background:rgba(99,102,241,.06)}

/* ============================================================
   CODE-CARD COMPONENTS (tutorial-specific)
   ============================================================ */
.lab{display:grid;gap:.9rem;grid-template-columns:1.15fr .85fr;align-items:start;max-width:1180px}
.lab.stack{grid-template-columns:1fr}
@media (max-width:900px){.lab{grid-template-columns:1fr}}

/* concept badge above a heading */
.concept{display:inline-flex;align-items:center;gap:.55em;font-family:var(--font-mono);
  font-size:.72rem;letter-spacing:.12em;text-transform:uppercase;font-weight:700;
  padding:.35em .8em;border-radius:999px;
  background:rgba(34,211,238,.14);border:1px solid rgba(34,211,238,.4);color:var(--cyan)}
.slide.light .concept{background:rgba(37,99,235,.1);border-color:rgba(37,99,235,.3);color:var(--blue)}

/* code block */
.codewrap{border-radius:16px;overflow:hidden;border:1px solid rgba(120,140,220,.28);
  box-shadow:0 26px 50px -28px rgba(0,0,0,.7);background:#0a0f24}
.codewrap .top{display:flex;align-items:center;gap:.5rem;padding:.55rem .9rem;
  background:linear-gradient(180deg,#131a36,#0d1430);border-bottom:1px solid rgba(120,140,220,.18)}
.codewrap .top .dot3{display:flex;gap:6px}
.codewrap .top .dot3 i{width:11px;height:11px;border-radius:50%;display:inline-block}
.codewrap .top .dot3 i:nth-child(1){background:#fb7185}
.codewrap .top .dot3 i:nth-child(2){background:#f59e0b}
.codewrap .top .dot3 i:nth-child(3){background:#10b981}
.codewrap .top .fname{font-family:var(--font-mono);font-size:.72rem;color:#9fb0e0;margin-left:.3rem}
pre.code{margin:0;padding:1rem 1.1rem;font-family:var(--font-mono);
  font-size:clamp(.74rem,1.02vw,.92rem);line-height:1.62;color:#e6ecff;
  white-space:pre;overflow:auto;max-height:54vh;tab-size:4}
pre.code::-webkit-scrollbar{height:8px;width:8px}
pre.code::-webkit-scrollbar-thumb{background:rgba(120,140,220,.4);border-radius:8px}

/* syntax colors */
.c-kw{color:#c792ea;font-weight:600}      /* keywords */
.c-bi{color:#82aaff}                      /* builtins */
.c-st{color:#c3e88d}                      /* strings */
.c-nu{color:#f78c6c}                      /* numbers */
.c-cm{color:#5f6b8c;font-style:italic}    /* comments */

/* output box */
.out{border-radius:16px;border:1px solid rgba(16,185,129,.35);overflow:hidden;
  background:#04140f}
.out .top{display:flex;align-items:center;gap:.5rem;padding:.5rem .9rem;
  background:rgba(16,185,129,.14);border-bottom:1px solid rgba(16,185,129,.3);
  font-family:var(--font-mono);font-size:.7rem;letter-spacing:.14em;text-transform:uppercase;color:#5eead4}
.out pre{margin:0;padding:.85rem 1.1rem;font-family:var(--font-mono);
  font-size:clamp(.74rem,1.02vw,.9rem);line-height:1.6;color:#d8ffe9;white-space:pre-wrap}
.out .usr{color:#fde68a}  /* what the user typed, in sample runs */

/* explainer note */
.note{font-size:.95rem;line-height:1.5}
.note b{color:var(--cyan)}
.slide.light .note b{color:var(--blue)}

/* "why it matters for your project" callout */
.why{display:flex;gap:.7rem;align-items:flex-start;border-radius:14px;padding:.8rem 1rem;
  background:rgba(217,70,239,.1);border:1px solid rgba(217,70,239,.32);font-size:.9rem;line-height:1.45}
.slide.light .why{background:rgba(168,85,247,.08);border-color:rgba(168,85,247,.28)}
.why .ic{font-size:1.1rem;line-height:1}
.why b{color:#f0abfc}
.slide.light .why b{color:#a21caf}

/* game banner */
.gamebar{display:inline-flex;align-items:center;gap:.6em;font-family:var(--font-mono);
  font-size:.74rem;letter-spacing:.1em;text-transform:uppercase;font-weight:700;
  padding:.4em .9em;border-radius:999px;color:#0a0f24;
  background:linear-gradient(90deg,var(--amber),var(--orange))}

/* section divider number list */
ol.steps{counter-reset:s;list-style:none;display:grid;gap:.55rem}
ol.steps li{display:flex;gap:.7rem;align-items:flex-start;line-height:1.45;counter-increment:s}
ol.steps li::before{content:counter(s);flex:0 0 auto;width:1.5em;height:1.5em;border-radius:50%;
  display:grid;place-items:center;font-family:var(--font-mono);font-size:.78rem;font-weight:700;
  background:rgba(99,102,241,.2);border:1px solid rgba(99,102,241,.45);color:#c7d2fe}

/* ============================================================
   TIMED SECTION TEST (15 questions · 15-minute timer)
   ============================================================ */
.exam-slide{justify-content:flex-start;padding-top:3.2vh}
.exam{display:flex;flex-direction:column;gap:.85rem;width:100%;max-width:1220px;margin:0 auto}

.exam-head{display:flex;align-items:center;justify-content:space-between;gap:1rem;flex-wrap:wrap}
.exam-title{font-family:var(--font-display);font-weight:700;font-size:clamp(1.2rem,2.5vw,1.85rem)}
.exam-tools{display:flex;align-items:center;gap:.55rem}
.exam-timer{font-family:var(--font-mono);font-weight:700;font-size:clamp(1.1rem,2.2vw,1.6rem);
  padding:.28em .7em;border-radius:12px;letter-spacing:.06em;min-width:5.4em;text-align:center;
  background:rgba(34,211,238,.14);border:1px solid rgba(34,211,238,.45);color:var(--cyan)}
.exam-timer.warn{background:rgba(251,113,133,.18);border-color:rgba(251,113,133,.55);color:#fda4af;animation:pulse 1s infinite}
.exam-timer.done{background:rgba(245,158,11,.18);border-color:rgba(245,158,11,.55);color:#fcd34d;font-size:clamp(.9rem,1.8vw,1.2rem)}
@keyframes pulse{50%{opacity:.5}}
.exam-btn{cursor:pointer;font-family:var(--font-mono);font-size:.76rem;font-weight:600;
  padding:.55em .9em;border-radius:10px;color:#eaf0ff;
  background:rgba(99,102,241,.22);border:1px solid rgba(120,140,220,.4);transition:.16s}
.exam-btn:hover{background:rgba(99,102,241,.42);transform:translateY(-1px)}
.exam-btn.ghost{background:transparent}

.exam-banner{font-size:.9rem;line-height:1.4;border-radius:12px;padding:.6rem .9rem;
  background:rgba(255,255,255,.06);border:1px solid rgba(170,190,255,.2)}
.exam-banner.live{background:rgba(16,185,129,.12);border-color:rgba(16,185,129,.4);color:#a7f3d0}
.exam-banner.reveal{background:rgba(245,158,11,.12);border-color:rgba(245,158,11,.42);color:#fde68a}

.exam-body{overflow:auto;max-height:63vh;padding-right:.4rem}
.exam-body::-webkit-scrollbar{width:9px}
.exam-body::-webkit-scrollbar-thumb{background:rgba(120,140,220,.4);border-radius:8px}
.exam-grid{display:grid;grid-template-columns:1fr 1fr;gap:.7rem}
@media (max-width:820px){.exam-grid{grid-template-columns:1fr}}

.qz{background:rgba(255,255,255,.05);border:1px solid rgba(160,180,255,.16);border-radius:14px;padding:.75rem .85rem}
.qz-code{border-left:3px solid rgba(34,211,238,.55)}
.qz-concept{border-left:3px solid rgba(139,92,246,.6)}
.qz-q{font-size:.92rem;line-height:1.45}
.qz-q code{font-family:var(--font-mono);font-size:.86em;background:rgba(99,102,241,.16);
  border:1px solid rgba(99,102,241,.28);border-radius:5px;padding:.05em .35em}
.qz-n{font-family:var(--font-mono);color:#cbd5ff;font-weight:700;margin-right:.2em}
.qz-tag{font-family:var(--font-mono);font-size:.6rem;letter-spacing:.1em;text-transform:uppercase;
  font-weight:700;padding:.22em .6em;border-radius:999px;margin-right:.45em;vertical-align:middle}
.qz-tag.code{background:rgba(34,211,238,.16);border:1px solid rgba(34,211,238,.4);color:var(--cyan)}
.qz-tag.concept{background:rgba(139,92,246,.2);border:1px solid rgba(139,92,246,.5);color:#c4b5fd}

.qz-input{display:block;width:100%;margin-top:.55rem;font-family:var(--font-mono);
  font-size:.82rem;line-height:1.5;color:#eaf0ff;background:rgba(6,10,26,.6);
  border:1px solid rgba(120,140,220,.3);border-radius:9px;padding:.5rem .6rem;
  resize:vertical;white-space:pre;overflow:auto}
.qz-input::placeholder{color:#5f6b8c}
.qz-input:focus{outline:none;border-color:var(--sky);background:rgba(6,10,26,.92)}

.qz-ans{display:none;margin-top:.6rem;border-top:1px dashed rgba(16,185,129,.45);padding-top:.55rem}
.qz-ans.show{display:block;animation:fade .3s ease}
.qz-ans-h{font-family:var(--font-mono);font-size:.64rem;letter-spacing:.12em;text-transform:uppercase;
  color:#6ee7b7;font-weight:700;margin-bottom:.35rem}
.qz-ans-t{font-size:.86rem;line-height:1.5;color:#d1fae5}
.qz-ans pre.code{max-height:none;padding:.6rem .8rem;font-size:.8rem;
  border:1px solid rgba(16,185,129,.3);border-radius:10px}

/* ---------- Overview grid ---------- */
#overview{position:fixed;inset:0;z-index:80;display:none;
  background:rgba(5,8,22,.93);backdrop-filter:blur(14px);
  padding:5vh 5vw;overflow:auto}
#overview.open{display:block;animation:fade .3s ease}
@keyframes fade{from{opacity:0}to{opacity:1}}
#overview h3{font-size:1.4rem;margin-bottom:1.4rem;color:#dfe6ff}
#ovGrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(190px,1fr));gap:14px}
.ov{cursor:pointer;border-radius:14px;padding:14px 14px 16px;min-height:92px;
  background:linear-gradient(160deg,rgba(99,102,241,.18),rgba(34,211,238,.08));
  border:1px solid rgba(160,180,255,.2);transition:.18s;display:flex;flex-direction:column;gap:8px}
.ov:hover{transform:translateY(-4px);border-color:var(--cyan);box-shadow:0 16px 30px -16px rgba(34,211,238,.6)}
.ov .n{font-family:var(--font-mono);font-size:.7rem;opacity:.7}
.ov .t{font-family:var(--font-display);font-weight:600;font-size:.95rem;line-height:1.15}
.ov.cur{border-color:var(--magenta);box-shadow:0 0 0 2px var(--magenta) inset}

/* title slide orbs */
.orb{position:absolute;border-radius:50%;filter:blur(2px);
  background:radial-gradient(circle at 30% 30%,#fff,rgba(34,211,238,.2) 40%,transparent 70%);
  opacity:.5;animation:floaty 7s ease-in-out infinite}
@keyframes floaty{50%{transform:translateY(-22px)}}

@media (max-width:760px){
  .slide{padding:6vh 7vw 11vh}
  .hide-sm{display:none!important}
}
@media print{.slide{position:relative;opacity:1!important;visibility:visible!important;page-break-after:always;height:100vh}}