:root{
  --navy-900:#0a1526;
  --navy-800:#0e1e36;
  --navy-700:#142c4d;
  --navy-600:#1b3a63;
  --blue-500:#4a9be8;
  --blue-300:#8ec4f2;
  --orange-500:#ff8a3d;
  --orange-400:#ffab6b;
  --orange-300:#ffcc9e;
  --text-100:#f2f5f9;
  --text-300:#c3cee0;
  --text-500:#8497b8;
  --font-display:'Space Grotesk', sans-serif;
  --font-body:'Inter', sans-serif;
  --font-mono:'JetBrains Mono', monospace;
}

*{box-sizing:border-box;}

html,body{
  margin:0;
  padding:0;
  height:100%;
  background:var(--navy-900);
  color:var(--text-100);
  font-family:var(--font-body);
  overflow:hidden;
}

.app{
  position:relative;
  height:100vh;
  width:100vw;
  display:flex;
  flex-direction:column;
  background:
    radial-gradient(1200px 600px at 85% -10%, rgba(74,155,232,0.16), transparent 60%),
    radial-gradient(900px 500px at -10% 110%, rgba(255,138,61,0.10), transparent 55%),
    var(--navy-900);
}

/* ---------- Tab bar (signature IDE motif) ---------- */
.tabbar{
  display:flex;
  gap:2px;
  padding:10px 16px 0;
  flex-shrink:0;
  overflow-x:auto;
  scrollbar-width:none;
}
.tabbar::-webkit-scrollbar{display:none;}

.tab{
  font-family:var(--font-mono);
  font-size:12.5px;
  padding:8px 16px;
  color:var(--text-500);
  background:var(--navy-800);
  border:1px solid var(--navy-600);
  border-bottom:none;
  border-radius:8px 8px 0 0;
  white-space:nowrap;
  transition:color .2s ease, background .2s ease;
  cursor:default;
}
.tab.active{
  color:var(--orange-400);
  background:var(--navy-700);
}
.tab .tab-part{
  display:block;
  font-size:9.5px;
  letter-spacing:.08em;
  text-transform:uppercase;
  color:var(--blue-300);
  margin-bottom:2px;
  opacity:.8;
}
.tab.active .tab-part{ color:var(--orange-300); }

/* ---------- Deck / slides ---------- */
.deck{
  position:relative;
  flex:1;
  min-height:0;
  background:var(--navy-700);
  border-top:1px solid var(--navy-600);
}

.slide{
  position:absolute;
  inset:0;
  opacity:0;
  visibility:hidden;
  transform:translateX(24px);
  transition:opacity .45s ease, transform .45s ease, visibility 0s linear .45s;
  overflow-y:auto;
}
.slide.active{
  opacity:1;
  visibility:visible;
  transform:translateX(0);
  transition:opacity .45s ease, transform .45s ease;
}
.slide.prev{ transform:translateX(-24px); }

.slide-inner{
  max-width:1180px;
  margin:0 auto;
  padding:56px 64px 90px;
  min-height:100%;
  display:flex;
  flex-direction:column;
  justify-content:center;
}

.eyebrow{
  font-family:var(--font-mono);
  font-size:13px;
  color:var(--orange-400);
  letter-spacing:.06em;
  margin-bottom:14px;
}

h1{
  font-family:var(--font-display);
  font-size:64px;
  line-height:1.04;
  font-weight:700;
  margin:0 0 20px;
  color:var(--text-100);
}
h1 .accent{ color:var(--orange-500); }

h2{
  font-family:var(--font-display);
  font-size:34px;
  font-weight:700;
  margin:0 0 18px;
  color:var(--text-100);
}
h2 code{ color:var(--blue-300); }

p{
  font-size:17px;
  line-height:1.65;
  color:var(--text-300);
  margin:0 0 14px;
}

code{
  font-family:var(--font-mono);
  font-size:.9em;
  color:var(--orange-300);
  background:rgba(255,138,61,0.08);
  padding:1px 6px;
  border-radius:5px;
}

/* ---------- title slide ---------- */
.title-slide{ align-items:flex-start; }
.subtitle{ font-size:19px; max-width:640px; }
.filetree{
  margin-top:26px;
  display:flex;
  flex-direction:column;
  gap:9px;
  font-family:var(--font-mono);
  font-size:14.5px;
  color:var(--text-300);
}
.filetree-row{ display:flex; align-items:center; gap:10px; }
.dot{ width:8px; height:8px; border-radius:50%; flex-shrink:0; }
.dot-orange{ background:var(--orange-500); box-shadow:0 0 10px rgba(255,138,61,.6); }
.dot-blue{ background:var(--blue-500); box-shadow:0 0 10px rgba(74,155,232,.6); }
.hint{
  margin-top:30px;
  font-size:13.5px;
  color:var(--text-500);
}

/* ---------- divider slides ---------- */
.divider-inner{ align-items:center; text-align:center; }
.divider .part-index{
  font-family:var(--font-display);
  font-size:20px;
  font-weight:700;
  color:var(--navy-900);
  background:linear-gradient(135deg, var(--orange-500), var(--blue-500));
  width:56px; height:56px;
  border-radius:16px;
  display:flex; align-items:center; justify-content:center;
  margin-bottom:22px;
}
.divider h2{ font-size:44px; }
.divider p{ font-size:19px; max-width:560px; }

/* ---------- two column layout ---------- */
.two-col{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:56px;
  align-items:center;
}
.col{ min-width:0; }

/* ---------- check list ---------- */
.check-list{
  list-style:none;
  margin:18px 0 0;
  padding:0;
  display:flex;
  flex-direction:column;
  gap:12px;
}
.check-list li{
  position:relative;
  padding-left:26px;
  font-size:15.5px;
  color:var(--text-300);
  line-height:1.5;
}
.check-list li::before{
  content:"";
  position:absolute;
  left:0; top:6px;
  width:11px; height:11px;
  border-radius:3px;
  background:linear-gradient(135deg,var(--orange-500),var(--blue-500));
}

/* ---------- code windows ---------- */
.code-window{
  background:var(--navy-800);
  border:1px solid var(--navy-600);
  border-radius:12px;
  overflow:hidden;
  box-shadow:0 20px 50px -20px rgba(0,0,0,.6);
}
.code-window.wide{ max-width:820px; margin:0 auto; }
.code-window-bar{
  display:flex;
  align-items:center;
  gap:8px;
  padding:10px 14px;
  background:var(--navy-700);
  border-bottom:1px solid var(--navy-600);
}
.wdot{ width:9px; height:9px; border-radius:50%; background:var(--navy-600); }
.wdot:nth-child(1){ background:#e8735a; }
.wdot:nth-child(2){ background:var(--orange-400); }
.wdot:nth-child(3){ background:var(--blue-300); }
.wname{
  margin-left:8px;
  font-family:var(--font-mono);
  font-size:12px;
  color:var(--text-500);
}

.code{
  margin:0;
  padding:20px 22px;
  font-family:var(--font-mono);
  font-size:14.5px;
  line-height:1.7;
  color:var(--text-100);
  overflow-x:auto;
}
.code.small{ font-size:13px; padding:16px; }
.code.big{ font-size:16px; padding:24px 26px; }

.c-kw{ color:var(--blue-300); }
.c-fn{ color:var(--orange-400); }
.c-arg{ color:var(--text-100); font-style:italic; }
.c-str{ color:#9fdc9f; }
.c-num{ color:#f2c14e; }
.c-cm{ color:var(--text-500); }
.c-pp{ color:var(--orange-400); }

/* ---------- anatomy diagram ---------- */
.anatomy{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:40px;
  align-items:center;
}
.anatomy-labels{
  display:flex;
  flex-direction:column;
  gap:16px;
}
.alabel{
  font-size:14.5px;
  color:var(--text-300);
  line-height:1.5;
  padding-left:14px;
  border-left:2px solid var(--navy-600);
}
.atag{
  display:block;
  font-family:var(--font-mono);
  font-size:12px;
  color:var(--orange-400);
  margin-bottom:3px;
}
.footnote{
  margin-top:22px;
  font-size:14.5px;
  color:var(--text-500);
}

/* ---------- process list ---------- */
.process{
  list-style:none;
  margin:8px 0 0;
  padding:0;
  display:flex;
  flex-direction:column;
  gap:16px;
}
.process li{
  display:flex;
  align-items:flex-start;
  gap:18px;
  font-size:15.5px;
  color:var(--text-300);
  line-height:1.5;
}
.process li strong{ color:var(--text-100); }
.pnum{
  flex-shrink:0;
  width:32px; height:32px;
  border-radius:9px;
  background:var(--navy-800);
  border:1px solid var(--navy-600);
  color:var(--orange-400);
  font-family:var(--font-mono);
  font-weight:600;
  display:flex; align-items:center; justify-content:center;
  font-size:14px;
}

/* ---------- mini card grid ---------- */
.card-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:18px;
  margin-top:10px;
}
.mini-card{
  background:var(--navy-800);
  border:1px solid var(--navy-600);
  border-radius:12px;
  padding:18px 20px;
}
.mini-card h3{
  font-family:var(--font-display);
  font-size:15px;
  color:var(--blue-300);
  margin:0 0 10px;
}
.mini-card pre{ margin:0; }

/* ---------- terminal ---------- */
.terminal{
  background:#081120;
  border:1px solid var(--navy-600);
  border-radius:12px;
  overflow:hidden;
}
.terminal-bar{
  padding:10px 14px;
  background:var(--navy-700);
  border-bottom:1px solid var(--navy-600);
  font-family:var(--font-mono);
  font-size:12px;
  color:var(--blue-300);
}
.term-out{
  margin:0;
  padding:20px 22px;
  font-family:var(--font-mono);
  font-size:14px;
  line-height:1.85;
  color:var(--text-300);
}
.t-in{ color:var(--orange-400); }

/* ---------- recap ---------- */
.recap-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:16px;
  margin-top:12px;
  max-width:760px;
}
.recap-card{
  background:var(--navy-800);
  border:1px solid var(--navy-600);
  border-radius:12px;
  padding:20px 22px;
  text-align:left;
}
.recap-card h3{
  font-family:var(--font-display);
  font-size:16px;
  color:var(--orange-400);
  margin:0 0 8px;
}
.recap-card p{ font-size:14px; margin:0; }

/* ---------- nav bar ---------- */
.navbar{
  flex-shrink:0;
  display:flex;
  align-items:center;
  justify-content:center;
  gap:22px;
  padding:14px;
  background:var(--navy-800);
  border-top:1px solid var(--navy-600);
}
.navbtn{
  width:36px; height:36px;
  border-radius:10px;
  border:1px solid var(--navy-600);
  background:var(--navy-700);
  color:var(--text-100);
  font-size:15px;
  cursor:pointer;
  display:flex; align-items:center; justify-content:center;
  transition:background .2s ease, border-color .2s ease, transform .15s ease;
}
.navbtn:hover{ background:var(--navy-600); border-color:var(--blue-500); }
.navbtn:active{ transform:scale(.92); }

.dots{ display:flex; gap:7px; align-items:center; }
.pdot{
  width:7px; height:7px;
  border-radius:50%;
  background:var(--navy-600);
  cursor:pointer;
  transition:background .2s ease, transform .2s ease;
}
.pdot:hover{ background:var(--blue-500); }
.pdot.active{
  background:var(--orange-500);
  transform:scale(1.35);
}

/* ---------- responsive ---------- */
@media (max-width:880px){
  .two-col, .anatomy{ grid-template-columns:1fr; gap:28px; }
  .card-grid, .recap-grid{ grid-template-columns:1fr; }
  .slide-inner{ padding:36px 24px 90px; }
  h1{ font-size:42px; }
  h2{ font-size:26px; }
  .divider h2{ font-size:32px; }
}